Alzheimer’s

Do Omega-3s Reduce Cognitive Decline?

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Should You Supplement With Omega-3s?

Author: Dr. Stephen Chaney 

Cognitive-DeclineDo omega-3s reduce cognitive decline, or is this another nutrition myth?

There is certainly good reason to believe that the long chain omega-3s EPA and DHA are good for brain health.

  • DHA is an essential part of the membrane that coats our neurons. As such, it is a major component of our brains and plays an important role in its structural integrity.
  • While EPA is not found in the brain it reduces inflammation and improves blood flow to the brain, both of which are important for brain health.

But the role of DHA and EPA in reducing cognitive decline remains controversial. Some studies strongly support their role in slowing cognitive decline while other studies find no effect.

So, the question remains, “Do omega-3s reduce cognitive decline or not?”

The study (B-Z Wei et al, American Journal of Clinical Nutrition, 117: 1096-1109, 2023) I will review today was designed to answer that question.

This study supports the hypothesis that omega-3s, especially DHA and EPA, reduce cognitive decline and Alzheimer’s disease. But it also raises several questions that need to be resolved by future studies.

Why Is The Effect Of Omega-3s On Cognitive Decline Controversial?

ArgumentWhy is it so difficult to come up with definitive answers about whether omega-3s reduce cognitive decline? It is probably because the relationship between omega-3s and brain health is complex. For example:

  • Because omega-3’s beneficial effects are widely publicized, many people are already consuming adequate amounts of omega-3s. A supplement study that does not measure the omega-3 status of participants at the beginning of the study and does not focus on participants with inadequate omega-3 status is doomed to failure.
  • Omega-3s may benefit older people more than younger people. A study that is not large enough to measure the effect of omega-3s on both groups is doomed to failure.
  • The APOE ɛ4 genotype is associated with an increased risk of cognitive decline and Alzheimer’s. Some studies suggest omega-3s are more beneficial for people with the APOE ɛ4 genotype, while other studies come to the opposite conclusion. This is a critical variable that needs to be resolved.
  • The ability of DHA to cross the blood-brain barrier and accumulate in our brain may be influenced by our genetics, especially our APOE ɛ4 status, and adequate levels of other nutrients, especially B vitamins. Unless studies are large enough to separate out these variables, they are doomed to failure. This study suggests accumulation of DHA in the brain is a critical variable that needs to be resolved.
  • Multiple studies suggest that higher doses of omega-3s are more effective at reducing cognitive decline than low doses of omega-3s. This study confirms that effect and identifies a threshold dose that is needed to provide measurable benefits. Studies providing supplemental omega-3s at doses below that threshold are likely to fail. And meta-analyses that combine low dose studies with high dose studies are also likely to come up empty.
  • Finally, people who take omega-3s for years are likely to benefit more than those who take omega-3s for just a few months. Again, this study confirms that effect, which means that studies involving short-term supplementation with omega-3s are likely to fail. And meta-analyses that combine short-term and long-term studies are likely to come up empty.

With so many potential pitfalls, it is easy to understand why many studies come up empty, and the effect of omega-3s on cognitive decline remains controversial.

How Was This Study Done?

clinical studyThis study consisted of two parts:

Part 1 used data from the Alzheimer’s Disease Neuroimaging Initiative (ADNI). The ADNI study is a multicenter study designed to develop clinical, imaging, genetic, and biochemical markers for early detection and tracking of Alzheimer’s Disease.

Participants undergo standardized neuroimaging, psychological assessments, in-person interviews for medical history, and cognitive evaluations on entry into the study and at the end of the study.

This study followed a cohort of 1135 participants (average age = 73, 46% females) without dementia at entry into the study for 6 years.

Omega-3 supplement use was determined based on a questionnaire at the beginning of the study. Participants who used omega-3 supplements for over a year were considered omega-3 users. They were further divided into medium-term users (1-9 years) and long-term users (>10 years).

Alzheimer’s Disease was diagnosed by neurologists based on brain scans, cognitive scores, and the ability to live independently.

Part 2 was a meta-analysis of 31 studies with 103,651 participants. The studies included in the meta-analysis all:

  • Measured the relationship of omega-3 intake with the risk of Alzheimer’s Disease, all-cause dementia, or cognitive decline.
  • Were cohort studies (studies that follow a group of people over time) or case control studies (studies that compare people who develop a disease with those who do not).
  • Provided risk estimates or data that could be used to calculate risk.
  • Were original publications, not reviews or meta-analyses.

Do Omega-3s Reduce Cognitive Decline?

omega 3 supplementsThe results from Part 1 (data from the ADNI study) were as follows:

  • Omega-3 supplement users had a 37% lower risk of developing Alzheimer’s Disease than non-users.
  • Long-term (>10 years) omega-3 supplement users fared even better. They had a 64% lower risk of developing Alzheimer’s Disease than non-users.
  • When they broke the results for long-term omega-3 supplement users into subgroups:
    • Males (67% risk reduction) benefitted more than females (50% risk reduction).
    • People over 65 (65% risk reduction) benefited more than those under 65 (22% risk reduction).
    • People with the APOE ɛ4 genotype (71% risk reduction) benefitted more than those who were APOE ɛ4 negative (55% risk reduction).

The results from Part 2 (data from the meta-analysis) were as follows:

  • Dietary omega-3 intake lowered the risk of cognitive decline by 9%.
    • People with the APOE ɛ4 genotype fared better (17% risk reduction).
    • Their data suggested that a threshold of 1 gm/day omega-3s was needed before significant risk reduction was seen.
  • Dietary DHA intake lowered the risk of dementia by 27% and Alzheimer’s Disease by 24%.
  • Each 100 mg/day increase in DHA and EPA was associated with a significant reduction in the risk of cognitive decline (8% for DHA and 9.9% for EPA).

The authors concluded that,

1) “Long-term omega-3 supplementation may reduce risk of Alzheimer’s Disease; and

2) Dietary omega-3 fatty acid intake, especially DHA, may lower risk of dementia or cognitive decline…

3) However, further investigation is needed to understand the gene environment interactions involved in…[these effects of omega-3 fatty acids].”

Should You Supplement With Omega-3s?

QuestionsThis study provides strong support for the hypothesis that omega-3 supplementation reduces the risk of cognitive decline, dementia, and Alzheimer’s Disease as we age. It also suggests that a dose of 1 gram/day may be needed to obtain a significant benefit.

However, it also highlights the difficulty in designing definitive experiments to test this hypothesis. This study shows that gender, age, genetics (especially the APOE ɛ4 genotype), type of omega-3s, dosage, and duration of supplementation all exert a significant influence on the effect of omega-3s on cognitive decline.

It is extremely difficult to design a study that optimizes all these variables, which almost guarantees that the effect of omega-3s on cognitive decline will remain controversial for the foreseeable future.

However, omega-3s lower blood pressure, lower triglycerides, reduce inflammation and are heart-healthy. And the threshold for all these effects is around 1 gram/day or more. If omega-3s also reduce cognitive decline, you can consider that a side-benefit.

The Bottom Line 

The role of omega-3s in reducing cognitive decline remains controversial. Some studies strongly support their role in slowing cognitive decline while other studies find no effect.

So, the question remains, “Do omega-3s reduce cognitive decline or not?”

A recent study was designed to answer that question. Among other things the study showed:

  • Omega-3 supplement users had a 37% lower risk of developing Alzheimer’s Disease than non-users.
  • Long-term (>10 years) omega-3 supplement users fared even better. They had a 64% lower risk of developing Alzheimer’s Disease than non-users.
  • Dietary DHA intake lowered the risk of dementia by 27% and Alzheimer’s Disease by 24%.
  • Each 100 mg/day increase in DHA and EPA was associated with a significant reduction in the risk of cognitive decline (8% for DHA and 9.9% for EPA).
  • The threshold for observing a significant effect of omega-3s on cognitive decline was around 1 gram/day.

This study provides strong support for the hypothesis that omega-3 supplementation reduces the risk of cognitive decline, dementia, and Alzheimer’s Disease as we age. It also suggests that a dose of 1 gram/day may be needed to obtain a significant benefit.

However, it also highlights the difficulty in designing definitive experiments to test this hypothesis. This study shows that gender, age, genetics (especially the APOE ɛ4 genotype), type of omega-3s, dosage, and duration of supplementation all exert a significant influence on the effect of omega-3s on cognitive decline.

It is extremely difficult to design a study that optimizes all these variables, which almost guarantees that the effect of omega-3s on cognitive decline will remain controversial for the foreseeable future.

However, omega-3s lower blood pressure, lower triglycerides, reduce inflammation and are heart-healthy. And the threshold for all these effects is around 1 gram/day or more. If omega-3s also reduce cognitive decline, you can consider that a side-benefit.

For more information on this study read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

 ___________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 

 

Does Hormone Replacement Therapy Cause Dementia?

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The Dark Side Of Hormone Replacement Therapy

Author: Dr. Stephen Chaney 

When I was still teaching, a physician and I were co-directors of one of the first courses medical students took at UNC. In his opening lecture to these brand-new medical students, one of his pearls of wisdom was the statement, “The only safe drug is a new drug.”

After a pause to let the students think about it, he followed up with, “That’s because the side effects haven’t been discovered yet.”

He would then go on to explain that every drug must go through rigorous clinical trials, and some side effects are discovered then. But some of the most serious side effects aren’t discovered until years later after 100’s of thousands of patients had used the drugs.

Hormone replacement therapy is a perfect example of this principle. Hormone replacement therapy was first introduced in the 1960s. At first it seemed to be an almost miraculous solution to menopausal symptoms.

Millions of women were overjoyed. After all, menopause symptoms can make life miserable. They include:

  • Hot flashes
  • Night sweats
  • Sleep disturbances
  • Mood swings
  • Depression
  • Anxiety
  • Forgetfulness
  • Food cravings
  • Tiredness

Just to name a few. While only 25% of women experience severe symptoms, why would anyone want to experience any of these symptoms?

And doctors were only too happy to oblige. Why not? The known side effects were mild. Why should any woman experience menopause symptoms?

But that was before the dark side of hormone replacement therapy started to emerge.

The Dark Side Of Hormone Replacement Therapy

Darth VaderThe popularity of hormone replacement therapy peaked in the 1990s. It was around that time that reports started to emerge suggesting that hormone replacement therapy increased the risk of heart disease and breast cancer. Those risks were confirmed in a major study called the Woman’s Health Initiative that was published in 2002.

That study caused a major shift in how the medical community regarded hormone replacement therapy. Within a few years doctors shifted from recommending hormone replacement therapy for every woman with menopausal symptoms to recommending it only in cases where the symptoms were debilitating and only for the shortest possible time.

The effect on women’s health was huge. In fact, switching from universal hormone replacement therapy to targeted hormone replacement therapy remains the single most effective public health measure for reducing the incidence of breast cancer. It is more effective than any of new drugs and measures to improve breast cancer screening since then.

I wish I could tell you that was the end of the story. But recent studies have suggested that hormone replacement therapy also increases the risk of dementia. Unfortunately, most of those studies have had flaws, so the link between hormone replacement therapy and dementia has remained controversial – until now.

The study (N Pourhadi et al, British Medical Journal, 382, e072770, 2023) I will describe today was designed to provide a more definitive test of this hypothesis.

How Was This Study Done?

clinical studyThis was done in Denmark and used the Danish health registries. As Americans, you might not be aware of what a rich resource those health registries are. One advantage of socialized medicine is that every aspect of your health is tracked and recorded from cradle to grave.

[I’m not sure I would be comfortable with our government knowing that much about me, but it is a treasure-trove of information if you want to conduct a study like this one.]

The authors used the Danish National Health registries to:

  • Identify all Danish women aged 50-60 who had no incidence of dementia and were not on hormone replacement therapy as of January 1, 2000.
  • Identify 5589 women (1.8% of the population) from this group who were diagnosed with dementia between January 1, 2000 and December 31, 2018 and match them with 55,890 controls who remained dementia-free through the end of 2018.
  • Using the National Prescription registry, they were able to track which women used hormone-replacement therapy, what kind of therapy it was (there are several variations of hormone replacement therapy), and how long they remained on hormone replacement therapy.

The average age at which hormone replacement therapy began was 53, and the average duration of use was 3.8 years. The average age of a dementia diagnosis was 70.

Does Hormone Replacement Therapy Cause Dementia?

Dementia-WomanWhen the authors compared women who used an estrogen-progestin combination hormone replacement therapy (the most common kind) with women who never used hormone replacement therapy, the hormone replacement therapy users were:

  • 24% more likely to develop dementia of any kind.
  • 21% more likely to develop late-onset dementia.
  • 22% more likely to develop Alzheimer’s disease.

Longer duration of hormone replacement use was associated with an increased risk of dementia. The increased risk of dementia was:

  • 21% for ≤ 1 year duration.
  • 39% for 8-12 years duration.
  • 74% for > 12 years duration.

The age at which hormone replacement therapy was begun had a slight effect on dementia risk. The increased risk of dementia was:

  • 26% when it was started at age 45-50.
  • 21% when it was started at age 51-60.

Finally, other forms of hormone replacement therapy such as progestin only therapy and vaginal estrogen treatment did not have a statistically significant effect on dementia risk. But it was not clear whether this was due to a smaller sample size or whether it was a true null effect.

The authors concluded, “Menopausal hormone replacement therapy was positively associated with the development of all cause dementia and Alzheimer’s disease, even in women who received treatment at the age of 55 years or younger.”

The Pros And Cons Of This Study

pros and consThe pros are obvious. This was a large, well-designed study. And its use of the Danish National Health registry and National Prescription registry allowed it to address the dementia risk of hormone replacement therapy in a comprehensive manner.

The cons are also obvious. This was an observational study. It can only show associations, not prove cause and effect. [I should note that it would be impossible to do a double-blind study to prove cause and effect. The size of the population group and the length of time required would make that kind of study unworkable.]

As I have said in previous issues of “Health Tips From the Professor”, the Achilles heel of observational studies is the possibility that a confounding variable (something else about the women who developed dementia) was the true cause of the observed outcome (in this case, increased dementia risk).

The authors did an excellent job of identifying known confounding variables that might have contributed to dementia and statistically correcting for them. However, the authors identified one potential confounding variable I would not have thought of.

In the words of the authors, “Further studies are warranted to determine whether these findings represent an actual effect of menopausal hormone therapy on dementia risk, or whether they reflect an underlying predisposition in women in need of these treatments.”

In case you need a translation, the authors are saying that it is possible that certain women have an underlying disease state or genetic predisposition that makes them very sensitive to menopausal symptoms (which increases the likelihood that they would receive hormone replacement therapy to reduce their symptoms) and increases their risk of dementia. In that case, it would be the underlying medical condition or genetic predisposition that was responsible for the increased dementia risk, not the hormone replacement therapy.”

I consider that unlikely, but it does warrant future studies.

Is Hormone Replacement Therapy Right For You?

Questioning WomanUltimately, this is your decision. But this is a decision you should make with your health care provider.

It is clear that hormone replacement therapy increases your risk of heart disease, breast cancer, and may increase your risk of dementia.

In part, your decision depends on the severity of your symptoms and your willingness to accept the risks associated with alleviating those symptoms.

But your health care provider can also help you consider family history and unrelated health conditions that may also increase your risk of these diseases. If your underlying disease risk is low, would you be more willing or less willing to accept the risks associated with hormone replacement therapy? Again, this is your decision.

And, if you decide to proceed with hormone replacement therapy, your health care provider can recommend the type of therapy and length of therapy that will minimize your risks.

The Bottom Line 

Several recent studies have suggested that hormone replacement therapy may increase the risk of dementia, but this has remained controversial.

In this issue of “Health Tips From the Professor” I share a very large, well designed study that supports the link between hormone replacement therapy and dementia.

When the authors of this study compared women who had used hormone replacement therapy with women who never used hormone replacement therapy, the hormone replacement therapy users were:

  • 24% more likely to develop dementia of any kind.
  • 21% more likely to develop late-onset dementia.
  • 22% more likely to develop Alzheimer’s disease.

The authors concluded, “Menopausal hormone replacement therapy was positively associated with the development of all cause dementia and Alzheimer’s disease, even in women who received treatment at the age of 55 years or younger.”

For more information on the strengths and weaknesses of this study and a discussion of whether hormone replacement therapy might be right for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

___________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 

Should Athletes Be Taking Omega-3s?

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Can Omega-3s Protect Your Brain?

Author: Dr. Stephen Chaney 

Contact sports like football and soccer can be an athlete’s ticket to fame and fortune. That is a powerful motivator. But many elite athletes in contact sports pay a terrible price after their playing days are over.

Repeated head trauma can lead to a condition called Chronic Trauma Encephalopathy or CTE. In CTE, a protein called Tau forms clumps that spread through the brain, killing brain cells. Eventually, this can lead to irrational behavior and/or early-onset Alzheimer’s, which is, indeed, a terrible price to pay for their brief moment in the spotlight.

The NCAA is aware of the damaging effects of repeated head trauma and are experimenting with rule changes and improvements to protective head gear to reduce it. But, given the pressures of college teams to win at all costs, it will be impossible to completely eliminate head trauma from contact sports.

So, it is important to ask, “What else we can do?” Several studies have suggested that omega-3s may mitigate the damaging effect of repeated head trauma. For example:

  • The omega-3s DHA and EPA are metabolized to molecules called resolvins and protectins, which protect brain tissue from oxidative stress and help restore damaged brain tissue.
  • DHA and EPA also reduce the inflammation associated with brain injury, so the brain can heal faster.
  • DHA and EPA boost the level of a protein called BDNF in the brain. It helps trigger the production of new brain cells, which also aids in the recovery from brain injury.
  • Finally, some medical clinics have reported that high dose omega-3s help speed the recovery from severe head trauma.
  • This is concerning because omega-3s are largely missing from the diet of college athletes.

This raises the question, “Should athletes be taking omega-3s?”omega 3 supplements

The kinds of studies mentioned above suggest that DHA and EPA might help protect athletes from the damaging effects of repeated head trauma, but it is difficult to prove:

  • If a patient comes into a clinic with severe brain trauma, the symptoms are obvious. And if omega-3s speed recovery it will become apparent in weeks or months. This effect is easy to measure.
  • On the other hand, the effects of repeated, minor head trauma on a highly trained athlete are often not apparent until decades later. Therefore, any protective effects of omega-3s would also not become apparent for decades. Clinical studies don’t last that long.

Because of this, current research focuses on markers of brain damage such as neurofilament light chain or Nf-L. Nf-L is a neuronal protein that is released into the bloodstream by dying neurons. It is widely considered to be an early marker for neurodegenerative diseases such as those seen in former college football players. Previous studies have shown:

  • Nf-L blood levels increase during the season for NCAA-level college football players.
  • College football players have a very low omega-3 index, a measure of omega-3 status.
  • DHA supplementation reduces Nf-L levels in college football players.

With this in mind, the authors of this study (JL Heileson et al, Journal of the International Society of Sports Nutrition 18:65, 2021) looked at the effect of a high-dose, comprehensive omega-3 supplement on Nf-L levels in the blood of NCAA football players during the playing season.

How Was This Study Done?

clinical studyVolunteers from two geographically distinct NCAA football teams were recruited for this study. One team (n=31) was given a daily high-dose omega-3 supplement providing 2,000 mg of DHA, 560 mg of EPA, and 320 mg of DPA starting during pre-season (fall) practices and continuing through the entire season. Compliance with the supplement regimen was 93%.

Volunteers from the other team (n=35) received no supplements and served as a control.

Participants from both teams were advised which foods were high in omega-3s and were asked to limit servings to no more than 2 per week for the duration of the study.

Players were excluded from the study if they:

  • Were on long-term (>20 days) anti-inflammatory therapy.
  • Were using fish oil supplements.
  • Ate more than two servings of fish per week.
  • Were on medications to control blood pressure or blood lipid levels.

Blood samples were drawn 7 days before pre-season practice, at the end of pre-season practice, 3 times during the season, and at the end of the season (a total of 6 blood draws).

The blood samples were analyzed for Nf-L, a marker of brain injury, and Omega-3 Index, a measure of omega-3 status.

Should Athletes Be Taking Omega-3s?

As I stated above, compliance with the supplementation regimen was excellent (93%) and this was reflected in the blood levels of long-chain omega-3s. Between the first and last blood sample drawn:

  • DHA and EPA levels increased 2-fold.
  • DPA levels, on the other hand, decreased slightly.
    • This suggests that the beneficial effects of omega-3 supplementation were primarily due to DHA and EPA. I will discuss the implications of this below.
  • The omega-3 index increased from 4.3%, which is considered poor, to 7.4%, which is considered near optimal.

The effect of omega-3 supplementation on Nf-L levels was striking:

  • In the control team (no supplementation) Nf-L levels increased 1.5-fold during the pre-season practices and remained elevated throughout the regular season.
  • In the team receiving omega-3 supplementation there was no significant increase in Nf-L levels.

The authors of the study concluded, “These findings suggest a…neuroprotective effect of combined EPA+DPA+DHA omega-3 fatty acid supplementation in American-style football athletes.”

The authors went on to say, “Similar elevations of Nf-L have been reported with RHI [repeated head injuries] in other contact sport athletes. These data suggest that those other contact sports athletes may also benefit from omega-3 supplementation…”

So, let’s return to the original question, “Should athletes be taking omega-3s?” Here is my take on the study:

  • The conclusions of the authors are appropriately cautious. This study shows that omega-3 supplementation reduces an indicator of possible brain damage (Nf-L), but the actual symptoms of brain damage don’t appear for decades.
    • Therefore, this study suggests, but doesn’t prove, that omega-3 supplementation may reduce Chronic Trauma Encephalopathy (CTE) for athletes who competed in contact sports during their college years.
  • This study used an omega-3 supplement containing EPA, DHA, and DPA. It resulted in an increase in EPA and DHA levels, but not DPA levels. Thus, there is no evidence that the DPA portion of the supplement was needed. I recommend a supplement with a 4:1 ratio of DHA to EPA for brain health.
  • This study did not establish an optimal dose of omega-3s. Until more information is available, I would recommend around 2,000 mg of DHA and 500 mg of EPA for athletes in contact sports, but the optimal dose may be lower or higher.

Can Omega-3s Protect Your Brain?

If you are not a college athlete competing in contact sports (which would include most of us), you are probably wondering what this means for you. Here are my thoughts.

As Benjamin Franklin said, “An ounce of prevention is worth a pound of cure.”

  • You never know when you may suffer unexpected head trauma. It could be a car accident. It could be a fall. You might be playing a friendly game of softball and get hit in the head by a foul ball. You get the point.
  • And the best time to make sure you have enough omega-3s (specifically DHA + EPA) in your brain is before the trauma occurs.

But how much DHA + EPA is enough? This is where it gets confusing.

  • Recommendations range from 500 mg/day to 3,000 mg/day depending on whether the goal is to reduce death from heart disease, lower blood pressure, or lower triglycerides.
  • This study used 2,500 mg/day to reduce a marker of brain damage in college athletes, but we don’t know whether that is optimal.
  • Finally, these numbers are averages, and none of us are average. We all utilize omega-3s from supplements with different efficiencies.

My recommendation is to use the Omega-3 Index as a gauge. It tells us how much DHA + EPA we have actually accumulated in our tissues.

  • An Omega-3 Index of 8% is considered optimal for heart health, and this study suggests it might be optimal for brain health as well.
  • So, my recommendation is to get your Omega-3 Index measured at 6-month intervals until you have determined the amount of supplemental DHA + EPA you need to attain and maintain an 8% Omega-3 Index.
  • Based on this study, I would recommend a high-purity supplement with an ~4:1 ratio of DHA to EPA if your primary goal is brain health. But other studies suggest that an EPA to DHA ratio of 3:2 may be optimal for heart health.

In short:

  • While the evidence is not definitive, this study suggests that it might be prudent to have accumulated enough DHA and EPA in your neural tissue to help reduce the complications of unexpected brain trauma.
  • This study also suggests that you may wish to aim for an Omega-3 Index of 8%.
    • An Omega-3 Index of 8% likely has side benefits. There is also evidence that it may reduce the rate of cognitive decline as you age, help protect your heart, and reduce inflammation.
  • The ratio of DHA to EPA in the supplement you choose may be different for brain health and heart health. If you are equally interested in brain and heart health, just be sure your supplement provides both DHA and EPA.

The Bottom Line 

Repeated head injuries are a major concern for NCAA football players and college athletes in other contact sports. That’s because repeated head injuries during their playing years are associated with a degenerative brain condition called Chronic Trauma Encephalopathy or CTE, which can lead to irrational behavior and/or early-onset Alzheimer’s.

A recent study looked at the effect of a high-dose, comprehensive omega-3 supplement on Nf-L, a marker of brain injury, in NCAA football players during the playing season. Two teams were selected.

  • In the team receiving no omega-3s, Nf-L increased 1.5-fold during preseason practice and remained elevated throughout the playing season.
  • In the team receiving omega-3 supplementation there was no significant increase in Nf-L levels.

The authors of the study concluded, “These findings suggest a…neuroprotective effect of… omega-3 fatty acid supplementation in American-style football athletes.”

The authors went on to say, “Similar elevations of Nf-L have been reported with RHI [repeated head injuries] in other contact sport athletes. These data suggest that those other contact sports athletes may also benefit from omega-3 supplementation…”

For more information on this study and what it means for all of us who are not college athletes, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

 ____________________________________________________________________________

My posts and “Health Tips From the Professor” articles carefully avoid claims about any brand of supplement or manufacturer of supplements. However, I am often asked by representatives of supplement companies if they can share them with their customers.

My answer is, “Yes, as long as you share only the article without any additions or alterations. In particular, you should avoid adding any mention of your company or your company’s products. If you were to do that, you could be making what the FTC and FDA consider a “misleading health claim” that could result in legal action against you and the company you represent.

For more detail about FTC regulations for health claims, see this link.

https://www.ftc.gov/business-guidance/resources/health-products-compliance-guidance

 

 

Can Lifestyle Overcome Bad Genes?

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Lifestyle, Genetics, And Dementia Risk 

Author: Dr. Stephen Chaney 

Cognitive-DeclineAlzheimer’s disease and other forms of dementia are among the most feared diseases of aging. What use is it to have a healthy body, a loving family, and a successful career if you can’t remember any of it? You should be able to enjoy your Golden years, not see them slip through your fingers.

If you have a family history of dementia or have sent your DNA off for testing and learned you are genetically predisposed to dementia, you are probably worried.

Perhaps the scariest thing about Alzheimer’s is that the medical community has no answers. There are no drugs to prevent or cure Alzheimer’s and brain transplants are out of the question. Some medical professionals will tell you nothing can be done, but is that true?

Before I answer that question let me share a fictional story because it provides a clue. In 1997, when I was still a relatively young scientist, I saw a film called GAATACA. [If you are looking for an entertaining film to watch, it is still available on some streaming services.]

This film envisioned a future society in which parents had their sperm and eggs sequenced so that their children would be genetically perfect. In that society the term “love child” had been redefined as a child who had been conceived without prior DNA sequencing.

The hero of this film was, of course, a love child. He was born with a genetic predisposition for heart disease. He was considered inferior, a second-class citizen of this future world.

Without giving away the plot of the film (I don’t want to spoil the enjoyment for you if you are thinking of watching it), he overcame his genetic inferiority. With a strict regimen of diet and physical fitness he became stronger and healthier than many of his genetically perfect peers.

This is when I first began to realize that our genes do not have to determine our destiny. We have the power to overcome bad genetics. We also have the power to undermine good genetics.

With that in mind, let’s return to Alzheimer’s. Studies have suggested that a healthy lifestyle can help reduce your risk of developing Alzheimer’s and other forms of dementia. But what about genetics? Will a healthy lifestyle only reduce your risk of dementia if your genetic risk is low, or will it be equally effective when your genetic risk is high? Can lifestyle overcome genetics?

The current study (A Tin et al, Neurology, 99: e154-e163, 2022) was designed to answer these questions.

How Was This Study Done?

clinical studyThis study included 11,561 participants from the Atherosclerosis Risk In Communities (ARIC) study. The ARIC study recruited middle-aged adults (average age of 54) from both urban and rural areas of the United States and followed them for 26 years. The participants were 57% female and 53% white.

Simply put, the study was designed to look at the effect of a healthy lifestyle on the genetic risk of developing dementia.

A healthy lifestyle was defined based on something called “Life’s Simple 7” (LS7) score.

  • The LS7 score was developed by the American Heart Association to define the effect of lifestyle on the risk of developing heart disease. However, it works equally well for defining the effect of lifestyle on risk of developing dementia.
  • The LS7 score consists of 7 modifiable health factors.
    • The factors are diet, physical activity, BMI (a measure of obesity), smoking, total cholesterol, blood pressure, and fasting blood glucose.
  • The data for deriving the LS7 scores were derived from data gathered from each participant when they enrolled in the ARIC study.
    • Diet was assessed by a 66-item food frequency questionnaire.
    • Physical activity and smoking were assessed in separate questionnaires.
    • BMI, blood pressure, total cholesterol, and fasting blood glucose were measured during a visit to a designated clinic at the beginning of the study.
  • Each modifiable health factor was separated into 3 categories (ideal, intermediate, and poor) and the highest score was assigned to the ideal category. The LS7 score was the sum of the scores from all 7 modifiable health factors.

Genetic risk of developing dementia was defined based on something called “The Genetic Risk Score” (GRS).

  • We have known for years that individuals of European descent who have the APOE ɛ4 gene variant have a 2 to 5-fold increased lifetime risk of developing dementia.
  • In recent years scientists have discovered several additional gene variants that increase the risk of dementia.
  • These have been combined with APOE ɛ4 to create a Genetic Risk Score for dementia.
  • The Genetic Risk Score for each participant was determined by DNA sequencing at the beginning of the study, with the highest score indicating the greatest risk for developing dementia.

The onset and severity of dementia were determined based on 7 clinic visits during the study.

  • Questionnaires were administered at each visit to assess self-reported dementia symptoms.
  • Cognitive tests were administered at visits 2 and 4.
  • Detailed cognitive and functional assessments were conducted at visits 5, 6, and 7.
  • The data were reviewed by an expert committee of physicians and neuropsychologists to determine dementia status.

Lifestyle, Genetics, And Dementia Risk

DNA TestingAt the end of the 26-year study:

  • When participants with the highest Genetic Risk Scores were compared to those with the lowest Genetic Risk Scores:
    • European American participants were 2.7-fold more likely to develop dementia.
    • African American participants were 1.55-fold more likely to develop dementia.
  • When participants with the highest LS7 (healthy lifestyle) scores were compared to those with the lowest LS7 scores:
    • European American participants were 40% less likely to develop dementia.
    • African American participants were 17% less likely to develop dementia.
    • A healthy lifestyle decreased the risk of developing dementia to a comparable extent at all levels of genetic risk for dementia.

The authors concluded, “Higher LS7 scores [a measure of a healthy lifestyle] are largely associated with a lower risk of incident dementia across strata of genetic risk [at all levels of genetic risk], supporting the use of LS7 [a healthy lifestyle] for maintaining brain health and offsetting genetic risk. More studies with larger study populations are needed…”

I should briefly comment on why African Americans were less responsive to both genetic risk and a healthy lifestyle than European Americans. The reasons for these discrepancies are not known, but:

  • There are socioeconomic factors and health disparities that increase the risk of dementia that are not included in the LS7 score.
  • A recent study has identified genetic risk factors for dementia that are unique to African Americans that are not included in the genetic risk score used in this study.

Can Lifestyle Overcome Bad Genes?

Dr. James Watson, who was co-discoverer of the DNA double helix and was heavily involved in the sequencing of the human genome, asked that he not be told about his risk of developing Alzheimer’s when his own DNA was sequenced in the early 2000’s. His reasoning was, “Why know the risk if you can’t change it?”

If the study I discussed today is true, you can modify the risk. Your genes don’t have to be your destiny. But is it true?

There is good reason to believe it might be true. Multiple studies have shown that each of the health factors included in LS7 score reduce the risk of developing dementia. However, most of those studies have not looked at the interaction between a healthy lifestyle and genetic risk.

Fortunately, there is another recent study that looked at the interaction between a healthy lifestyle and genetic risk of developing dementia.

  • This study used a different database (The UK Biobank study which enrolled 500,000 participants) and different criteria for defining a healthy lifestyle (diet, physical activity, smoking, and alcohol use).

However, the conclusions of this study were very similar:

  • People at high genetic risk were almost twice as likely to develop dementia as those at low genetic risk.
  • A healthy lifestyle decreased the risk of developing dementia by about 40% for both people at high genetic risk and for people at low genetic risk.

But this study went one step further than the study I discussed in this article. The British study reported that:

  • People at low genetic risk and an unhealthy lifestyle (the typical American) were just as likely to develop dementia as people at high genetic risk and a healthy lifestyle.

In other words, bad genetics does not doom you to Alzheimer’s and dementia. A healthy lifestyle can cut your risk almost in half. Conversely, good genetics is not a “Get Out of Jail Free” card. You can squander the advantage of good genetics with an unhealthy lifestyle.

And, just like the hero of the movie I discuss at the beginning of this article, a healthy lifestyle may be able to overcome bad genes and make you just as healthy (with respect to the risk of developing dementia) as people with good genes and an unhealthy lifestyle – which includes most Americans.

The Bottom Line 

Alzheimer’s disease and other forms of dementia are among the most feared diseases of aging. What use is it to have a healthy body, a loving family, and a successful career if you can’t remember any of it?

If you have a family history of dementia or have sent your DNA off for testing and learned you are genetically predisposed to dementia, you are probably worried.

Perhaps the scariest thing about Alzheimer’s is that the medical community has no answers. There are no drugs to prevent or cure Alzheimer’s and brain transplants are out of the question. Some medical professionals will tell you nothing can be done, but is that true?

Studies have suggested that a healthy lifestyle can help reduce your risk of developing Alzheimer’s and other forms of dementia. But what about genetics? Will a healthy lifestyle only reduce your risk of dementia if your genetic risk is low, or will it be equally effective when your genetic risk is high? Can lifestyle overcome genetics?

A recent study was designed to answer these questions. It found:

  • When participants with the highest Genetic Risk Scores were compared to those with the lowest Genetic Risk Scores:
    • They were 1.5 to 2.7-fold more likely to develop dementia.
  • When participants with the highest LS7 (healthy lifestyle) scores were compared to those with the lowest LS7 scores:
    • They were 17% to 40% less likely to develop dementia.
  • A healthy lifestyle decreased the risk of developing dementia to a comparable extent at all levels of genetic risk for dementia.

The authors concluded, “Higher LS7 scores [a measure of a healthy lifestyle] are largely associated with a lower risk of incident dementia across strata of genetic risk [at all levels of genetic risk], supporting the use of LS7 [a healthy lifestyle] for maintaining brain health and offsetting genetic risk. More studies with larger study populations are needed…”

This, and other studies discussed in this issue of “Health Tips For The Professor” suggest that your genes don’t have to determine your destiny. You can overcome bad genes with a healthy lifestyle.

For more details on this study, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Can Diet Protect Your Mind?

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Which Diet Is Best?

Author: Dr. Stephen Chaney 

can diet prevent alzheimer'sAlzheimer’s is a scary disease. There is so much to look forward to in our golden years. We want to enjoy the fruits of our years of hard work. We want to enjoy our grandkids and perhaps even our great grandkids. More importantly, we want to be able to pass on our accumulated experiences and wisdom to future generations.

Alzheimer’s and other forms of dementia have the potential to rob us of everything that makes life worth living. What is the use of having a healthy body, family, and fortune if we can’t even recognize the people around us?

Alzheimer’s and other forms of dementia don’t happen overnight. The first symptoms of cognitive decline are things like forgetting names, where you left things, what you did last week. For most people it just keeps getting worse.

Can diet protect your mind? Recent studies have given us a ray of hope. For example, several meta-analyses have shown that adherence to the Mediterranean diet was associated with a 25-48% lower risk of cognitive decline and dementia.

However, there were several limitations to the studies included in these meta-analyses. For example:

  • For most of the studies the diet was assessed only at the beginning of the study. We have no idea whether the participants followed the same diet throughout the study. This means, we cannot answer questions like:
    • What is the effect of long-term adherence to a healthy diet?
    • Can you reduce your risk of cognitive decline if you switch from an unhealthy diet to a healthy diet?
  • These studies focused primarily on the Mediterranean diet. This leaves the question:
    • What about other healthy diets? Is there something unique about the Mediterranean diet, or do other healthy diets also reduce the risk of cognitive decline?

This study (C Yuan et al, American Journal of Clinical Nutrition, 115: 232-243, 2022) was designed to answer those questions.

How Was The Study Done?

clinical studyThe investigators utilized data from The Nurse’s Health Study. They followed 49,493 female nurses for 30 years from 1984 to 2014. The average age of the nurses in 1984 was 48 years, and none of them had symptoms of cognitive decline at the beginning of the study.

The nurse’s diets were analyzed in 1984, 1986, and every 4 years afterwards until 2006. Diets were not analyzed during the last 8 years of the study to eliminate something called “reverse causation”. Simply put, the investigators were trying to eliminate the possibility that participants in the study might change their diet because they were starting to notice symptoms of cognitive decline.

The data from the dietary analyses were used to calculate adherence to 3 different healthy diets:

  • The Mediterranean diet.
  • The DASH diet. The DASH diet was designed to reduce the risk of high blood pressure. But you can think of it as an Americanized version of the Mediterranean diet.
  • The diet recommended by the USDA. Adherence to this diet is evaluated by something called the Alternative Healthy Eating Index or AHEI.

Adherence to each diet was calculated by giving a positive score to foods that were recommended for the diet and a negative score for foods that were not recommended for the diet. For more details, read the article.

In 2012 and 2014 the nurses were asked to fill out questionnaires self-assessing the early stages of cognitive decline. They were asked if they had more trouble than usual:

  • Remembering recent events or remembering a short list of items like a grocery list (measuring memory).
  • Understanding things, following spoken instructions, following a group conversation, or following a plot in a TV program (measuring executive function).
  • Remembering things from one second to the next (measuring attention).
  • Finding ways around familiar streets (measuring visuospatial skills).

The extent of cognitive decline was calculated based on the number of yes answers to these questions.

Can Diet Protect Your Mind?

Vegan FoodsHere is what the investigators found when they analyzed the data:

At the beginning of the study in 1984 there were 49,493 female nurses with an average age of 48. None of them had symptoms of cognitive decline.

  • By 2012-2014 (average age = 76-78) 46.9% of them had cognitive decline and 12.3% of them had severe cognitive decline.

Using the data on dietary intake and the rating systems specific to each of the diets studied, the investigators divided the participants into thirds based on their adherence to each diet. The investigators then used these data to answer two important questions that no previous study had answered:

#1: What is the effect of long-term adherence to a healthy diet? To answer this question the investigators averaged the dietary data obtained every 4 years between 1984 and 2006 to obtain cumulative average scores for adherence to each diet. When the investigators compared participants with the highest adherence to various healthy diets for 30 years to participants with the lowest adherence to those diets, the risk of developing severe cognitive decline was decreased by:

  • 40% for the Mediterranean diet.
  • 32% for the DASH diet.
  • 20% for the USDA-recommended healthy diet (as measured by the AHEI score).

#2: Can you reduce your risk of cognitive decline if you switch from an unhealthy diet to a healthy diet? To answer this question, the investigators looked at participants who started with the lowest adherence to each diet and improved to the highest adherence by the end of the study. This study showed that improving from an unhealthy diet to a healthy diet over 30 years decreased the risk of developing severe cognitive decline by:

  • 20% for the Mediterranean diet.
  • 25% for the DASH diet.

There were a few other significant observations from this study.

  • The inverse association between healthy diets and risk of cognitive decline was greater for nurses who had high blood pressure.
    • This is an important finding because high blood pressure increases the risk of cognitive decline.
  • The inverse association between healthy diets and risk of cognitive decline was also greater for nurses who did not have the APOE-ɛ4 gene.
    • This illustrates the interaction of diet and genetics. The APOE-ɛ4 gene increases the risk of cognitive decline. Healthy diets reduced the risk of cognitive decline in nurse with the APOE-ɛ4 gene but not to the same extent as for nurses without the gene.

This study did not investigate the mechanism by which healthy diets reduced the risk of cognitive decline, but the investigators speculated it might be because these diets:

  • Were anti-inflammatory.
  • Supported the growth of healthy gut bacteria.

The investigators concluded, “Our findings support the beneficial roles of long-term adherence to the [Mediterranean, DASH, and USDA] dietary patterns for maintaining cognition in women…Further, among those with initially relatively low-quality diets, improvement in diet quality was associated with a lower likelihood of developing severe cognitive decline. These findings indicate that improvements in diet quality in midlife and later may have a role in maintenance of cognitive function among women.”

Which Diet Is Best?

Mediterranean Diet FoodsIn a sense this is a trick question. That’s because this study did not put the participants on different diets. It simply analyzed the diets the women were eating in different ways. And while the algorithms they were using were diet-specific, there was tremendous overlap between them. For more specifics on the algorithms used to estimate adherence to each diet, read the article.

That is why the investigators concluded that all three diets they analyzed reduced the risk of cognitive decline rather than highlighting a specific diet. However, based on this and numerous previous studies the evidence is strongest for the Mediterranean and DASH diets.

And I would be remiss if I didn’t also mention the MIND diet. While it was not included in this study, the MIND diet:

  • Was specifically designed to reduce cognitive decline.
  • Can be thought of as a combination of the Mediterranean and DASH diets.
  • Includes data from studies on the mind-benefits of individual foods. For example, it recommends berries rather than all fruits.

The MIND diet has not been as extensively studied as the Mediterranean and DASH diets, but there is some evidence that it may be more effective at reducing cognitive decline than either the Mediterranean or DASH diets alone.

Which Foods Are Best?

AwardThe authors of this study felt it was more important to focus on foods rather than diets. This is a better approach because we eat foods rather than diets. With that in mind they analyzed their data to identify the foods that prevented cognitive decline and the foods increased cognitive decline. This is what they found:

  • Fruits, fruit juices, vegetables, fish, nuts, legumes, low-fat dairy, and omega-3 fatty acids (fish oil) reduced the risk of cognitive decline.
  • Red and processed meats, omega-6 fatty acids (most vegetable oils), and trans fats increased the risk of cognitive decline.

While this study did not specifically look at the effect of processed foods on cognitive decline, diets high in the mind-healthy foods listed above are generally low in sodas, sweets, and highly processed foods.

What Does This Study Mean For You?

Question MarkThe question, “Can diet protect your mind”, is not a new one. Several previous studies have suggested that healthy diets reduce the risk of cognitive decline, but this study breaks new ground. It shows for the first time that:

  • Long-term adherence to a healthy diet can reduce your risk of cognitive decline by up to 40%.
    • This was a 30-year study, so we aren’t talking about “diet” in the traditional sense. We aren’t talking about short-term diets to drop a few pounds. We are talking about a life-long change in the foods we eat.
  • If you currently have a lousy diet, it’s not too late to change. You can reduce your risk of cognitive decline by switching to a healthier diet.
    • This is perhaps the best news to come out of this study.

Based on current evidence, the best diets for protecting against cognitive decline appear to be the Mediterranean, DASH, and MIND diets.

And if you don’t like restrictive diets, my advice is to:

  • Eat more fruits, fruit juices, vegetables, fish, nuts, legumes, low-fat dairy, and omega-3 fatty acids (fish oil).
  • Eat less red and processed meats, omega-6 fatty acids (most vegetable oils), and trans fats.
  • Eat more plant foods and less animal foods.
  • Eat more whole foods and less sodas, sweets, and processed foods.

And, of course, a holistic approach is always best. Other lifestyle factors that help reduce your risk of cognitive decline include:

  • Regular exercise.
  • Weight control.
  • Socialization.
  • Memory training (mental exercises).

The Bottom Line 

Alzheimer’s is a scary disease. What is the use of having a healthy body, family, and fortune if we can’t even recognize the people around us?

A recent study looked at the effect of diet on cognitive decline in women. The study started with middle-aged women (average age = 48) and followed them for 30 years. The investigators then used these data to answer two important questions that no previous study had answered:

#1: What is the effect of long-term adherence to a healthy diet? When the investigators compared participants with the highest adherence to various healthy diets for 30 years to participants with the lowest adherence to those diets, the risk of developing severe cognitive decline was decreased by:

  • 40% for the Mediterranean diet.
  • 32% for the DASH diet.
  • 20% for the USDA recommendations for a healthy diet.

#2: Can you reduce your risk of cognitive decline if you switch from an unhealthy diet to a healthy diet? This study showed that improving from an unhealthy diet to a healthy diet over 30 years decreased the risk of developing severe cognitive decline by:

  • 20% for the Mediterranean diet.
  • 25% for the DASH diet.

The investigators concluded, “Our findings support the beneficial roles of long-term adherence to the [Mediterranean, DASH, and USDA] dietary patterns for maintaining cognition in women…Further, among those with initially relatively low-quality diets, improvement in diet quality was associated with a lower likelihood of developing severe cognitive decline. These findings indicate that improvements in diet quality in midlife and later may have a role in maintenance of cognitive function among women.”

For more details on the study, which diets, and which foods are best for protecting your mind, and what this study means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

Does Olive Oil Help You Live Longer?

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Which Fat Is Healthiest?

Author: Dr. Stephen Chaney

If you believe the headlines, olive oil is a superfood. It is often described as the star of the Mediterranean diet. It is referred to as the healthiest of dietary fats. Is this true, or is it hype?

Olive oil’s resume is impressive:

  • It is rich in monounsaturated fatty acids, which…
    • Are less susceptible to oxidation than polyunsaturated oils.
    • Make our arteries more flexible, which lowers blood pressure.
    • Lower LDL-cholesterol levels, which reduces the risk of heart disease.
  • Extra-virgin olive oil contains phytonutrients and tocopherols (various forms of vitamin E), which…
    • Have anti-inflammatory properties.
    • Improve insulin sensitivity and blood sugar control.
  • Olive oil consumption is also associated with healthier gut bacteria, but it is not clear whether this is due to olive oil or to the fact that a Mediterranean diet is also richer in fresh fruits, vegetables, and whole grains.

Several recent studies have shown that olive oil consumption is associated with a lower risk of heart disease. However, these studies were conducted in Mediterranean countries where the average intake of olive oil (3 tablespoons/day) is much greater than in the United States (0.3 tablespoons/day).

The current study (M Guasch-Ferré et al, Journal of the American College of Cardiology, 79: 101-112, 2022) was designed to test whether:

  • The amount of olive oil Americans consume decreases the risk of heart disease.
  • Whether olive oil consumption had benefits beyond a reduction in heart disease risk.

How Was This Study Done? 

Clinical StudyThis study combined data from 60,582 women enrolled in the Nurses’ Health Study and 31,801 men enrolled in the Health Professionals Follow-Up Study). The participants:

  • Were free of heart disease and diabetes at the start of the study.
  • Were 56 at the start of the study with an average BMI of 25.6 (Individuals with BMIs in the 25-30 range are considered overweight, so they were at the lowest end of the overweight range).

The Nurses’ Health Study and Health Professional Follow-Up Study are both association studies, meaning they looked at the association between olive oil consumption and health outcomes. They cannot directly prove cause and effect. However, they are very strong association studies because:

  • Every 2 years, participants filled out a questionnaire that updated information on their body weight, smoking status, physical activity, medications, multivitamin use, and physician-diagnosed diseases.
  • Every 4 years, participants filled out a comprehensive food frequency questionnaire.
  • In other words, this study did not just rely on the participant’s lifestyle, dietary intake, and health at the beginning of the study, as so many association studies do. It tracked how each of these variables changed over time.

The participants were followed for an average of 28 years and their average olive oil intake over those 28 years was correlated with all-cause mortality and mortality due to specific diseases.

  • Deaths were identified from state vital statistics, the National Death index, reports by next of kin, or reports by postal authorities.
  • Causes of death were determined by physician review of medical records, medical reports, autopsy reports, or death certificates.

Does Olive Oil Help You Live Longer?

During the 28 years of this study:

  • Olive oil consumption in the United States increased from an average of ~1/3 teaspoon/day to ~1/3 tablespoon/day.
  • Margarine consumption decreased from 12 g/day to ~4 g/day.
  • The consumption of all other fats and oils remained about the same.

As I mentioned above, olive oil consumption was averaged over the life of the study for each individual. When the investigators compared people consuming the highest amount of olive oil (>0.5 tablespoon/day) with people consuming the least olive oil (0 to 1 teaspoon/day):

  • Mortality from all causes was decreased by 35% for the group consuming the most olive oil.

However, the group consuming the most olive oil also was more physically active, had a healthier diet, and consumed more fruits and vegetables than the group who consumed the least olive oil.

  • After correcting for all those factors, mortality from all causes was decreased by 19% for the group consuming the most olive oil.

The authors concluded, “We found that greater consumption of olive oil was associated with lower risk of total…mortality… Our results support current dietary recommendations to increase the intake of olive oil…to improve overall health and longevity.” (I will fill in the blanks in this statement once I have covered other aspects of this study)

The authors also said, “Of note, our study showed that benefits of olive oil can be observed even when consumed in lower amounts than in Mediterranean countries.”

Are There Other Benefits From Olive Oil Consumption?

Mediterranean dietThe study didn’t stop there. The investigators also looked at the effect of olive oil consumption on the major killer diseases in the United States and other developed countries. When they compared the effect of olive oil consumption on cause-specific mortality, they found that the group who consumed the most olive oil reduced their risk of dying from:

  • Cardiovascular disease by 19%.
  • Cancer by 17%
  • Respiratory disease by 18%.
  • Neurodegenerative disease (cognitive decline and Alzheimer’s disease) by 29%.
    • The reduction in neurodegenerative disease was much greater for women (34% decrease) than for men (19% decrease).

With this information I can fill in one of the blanks in the author’s conclusions: “We found that greater consumption of olive oil was associated with lower risk of total and cause-specific mortality… Our results support current dietary recommendations to increase the intake of olive oil…to improve overall health and longevity.”

Which Fats Are Healthiest?

Good Fat vs Bad FatThe sample size was large enough and the dietary information complete enough for the investigators to also estimate the effect of substituting olive oil for other dietary fats and oils.

They found that every ¾ tablespoon of olive oil substituted for an equivalent amount of:

  • Margarine decreased total mortality by 13%.
  • Butter decreased total mortality by 14%.
  • Mayonnaise deceased total mortality by 19%
  • Dairy fat decreased total mortality by 13%.
    • The same beneficial effects of substituting olive oil for other fats were seen for cause-specific mortality (cardiovascular disease, cancer, respiratory disease, and neurodegenerative disease).
    • There was a linear dose-response. This means that substituting twice as much olive oil for other dietary fats doubled the beneficial effects on total and cause-specific mortality.
  • However, substituting olive oil for polyunsaturated vegetable oils had no effect on total and cause-specific mortality.

Now I can fill in the remaining blanks in the author’s conclusion: “We found that greater consumption of olive oil was associated with lower risk of total and cause-specific mortality. Replacing other types of fat, such as margarine, butter, mayonnaise, and dairy fat, with olive oil was also associated with a lower risk of mortality. Our results support current dietary recommendations to increase the intake of olive oil and other unsaturated vegetable oils in place of other fats to improve overall health and longevity.”

What Does This Study Mean For Us?

ConfusionAs I said above, this is an association study, and association studies do not prove cause and effect. However:

1) This is a very strong association study because:

    • It is a very large study (92,383 participants).
    • It followed the participants over a long time (28 years).
    • It utilized a very precise dietary analysis.
    • Most importantly, it tracked the participant’s lifestyle, dietary intake, and health at regular intervals throughout the study. Most association studies only measure these variables at the beginning of the study. They have no idea how they change over time.

2) This study is consistent with several previous studies showing that olive oil consumption decreases the risk of dying from heart disease.

3) This study draws on its large population size and precise dietary analysis to strengthen and extend the previous studies. For example:

    • The study showed that increased olive oil consumption also reduced total mortality and mortality due to cancer, respiratory disease, and neurodegenerative disease.
    • The study measured the effect of substituting olive oil for other common dietary fats.
    • The study showed that increased olive oil consumption in the context of the American diet was beneficial.

I should point out that the headlines you have seen about this study may be misleading.

  • While the headlines may have depicted olive oil as a superfood, this study did not find evidence that olive oil was more beneficial than other unsaturated vegetable oils. Again, this is consistent with many previous studies showing that substituting vegetable oils for other dietary fats reduces the risk of multiple diseases.
  • The headlines focused on the benefits of increasing olive oil consumption. However, they neglected the data showing that increasing olive oil (and other vegetable oils) was even more beneficial (35% reduction in total mortality) in the context of a healthy diet – one with increased intake of fruits, vegetables, whole grains, nuts, legumes, and long-chain omega-3s and decreased intake of red & processed meats, sodium, and trans fats.

So, my recommendation is to follow a whole food, primarily plant-based diet and substitute extra-virgin olive oil and cold pressed vegetable oils for some of the animal fats in your diet.

Some vegan enthusiasts recommend a very low-fat whole food plant-based diet. They point to studies showing that such diets can actually reverse atherosclerosis. However:

  • Those studies are very small.
  • The overall diet used in those studies is a very healthy plant-based diet.
  • The studies did not include a control group following the same diet with olive oil or other vegetable oils added to it, so there is no comparison of a healthy vegan diet with and without vegetable oils.

If you have read my book, “Slaying the Food Myths”, you know that my recommendations encompass a variety of whole food, primarily plant-based diets ranging all the way from very-low fat vegan diets to Mediterranean and DASH diets. Choose the one that best fits your food preferences and the one you will be most able to stick with long term. You will be healthier, and you may live longer.

The Bottom Line

A recent study looked at the effect of olive oil consumption on the risk dying from all causes and from heart disease, cancer, respiratory disease, and neurodegenerative diseases. When the study compared people consuming the highest amount of olive oil (>0.5 tablespoon/day) with people consuming the least olive oil (0 to 1 teaspoon/day):

  • Mortality from all causes was decreased by 19% for the group consuming the most olive oil.

They also found that the group who consumed the most olive oil reduced their risk of dying from:

  • Cardiovascular disease by 19%.
  • Cancer by 17%
  • Respiratory disease by 18%.
  • Neurodegenerative disease (cognitive decline and Alzheimer’s disease) by 29%.

They also found that every ¾ tablespoon of olive oil substituted for an equivalent amount of:

  • Margarine decreased total mortality by 13%.
  • Butter decreased total mortality by 14%.
  • Mayonnaise deceased total mortality by 19%
  • Dairy fat decreased total mortality by 13%.
  • However, substituting olive oil for polyunsaturated vegetable oils had no effect on total and cause-specific mortality.

The authors concluded, “We found that greater consumption of olive oil was associated with lower risk of total and cause-specific mortality. Replacing other types of fat, such as margarine, butter, mayonnaise, and dairy fat, with olive oil was also associated with a lower risk of mortality. Our results support current dietary recommendations to increase the intake of olive oil and other unsaturated vegetable oils in place of other fats to improve overall health and longevity.”

For more details and a summary of what this study means for you, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Can Your Diet Cause You To Lose Your Mind?

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What Is A Mind-Healthy Lifestyle? 

Author: Dr. Stephen Chaney

Cognitive-DeclineMost of us look forward to our golden years – that mystical time when we will be free from the workday pressures and have more time to spend with friends and family doing the things we love.

But cognitive decline can cast a dark cloud over those expectations.

  • By the age of 65, 11% of adults suffer from some degree of cognitive impairment.
  • And by the age of 80 the percentage of adults suffering from cognitive impairment has increased to 26-30%, depending on which study you cite.

The results of cognitive decline can be devastating.

  • First you start to lose the cherished memories of a lifetime.
  • Then comes confusion and an inability to perform basic tasks and participate in your favorite activities.
  • Eventually you may reach a stage where you no longer recognize the ones you love.

In short, cognitive decline can rob you of everything that makes you you.

The causes of cognitive decline are complex, but recent studies have pointed to the role of chronic inflammation in cognitive decline. If that is true, it is a good news – bad news situation.

  • The bad news is:
    • Some increase in chronic inflammation appears to be an inevitable consequence of aging.
    • Chronic inflammation can be caused by certain diseases that are beyond our control.
    • Chronic inflammation can be triggered by viral or bacterial infections.
  • The good news is that chronic inflammation is also controlled by your diet and lifestyle. For example, as I said above, chronic inflammation is often triggered by a viral infection, but whether the inflammation is mild or severe is strongly influenced by diet and lifestyle.

In this issue of “Health Tips From the Professor” I share a study (S Charisis et al, Neurology, In Press, November 10, 2021) showing that diets high in inflammatory foods increase the risk of dementia. Then, I answer 3 important questions.

  • Can your diet cause you to lose your mind?
  • What is a mind-healthy diet?
  • What is a mind-healthy lifestyle?

How Was This Study Done?

Clinical StudyThe data for this study were taken from the first three years of the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD), a study designed to look at the effect of diet on dementia and other neuropsychiatric conditions in the Greek population.

There were 1059 participants (40% male, average age = 75 at the beginning of the study) in this study. At the beginning of the study the participants completed a food frequency questionnaire administered by a trained dietitian. The foods were broken down into individual nutrients using the USDA Food Composition tables adapted for foods in the Greek diet.

The diet of each participant was then rated on a 15-point scale ranging from pro-inflammatory to anti-inflammatory based on something called the Diet Inflammation Index (DII).

Simply put, the DII is a validated assessment tool based on the effect of food nutrients on 6 inflammatory biomarkers found in the blood (IL-1β, IL-4, IL-6, IL-10, TNF-α, and CRP). Nutrients that decrease these markers are considered anti-inflammatory. Nutrients that increase these inflammatory biomarkers are considered pro-inflammatory.

For example, anti-inflammatory nutrients include:

  • Carotenoids and flavonoids (found in fruits and vegetables).
  • Omega-3 polyunsaturated fatty acids (found in cold-water fish, walnuts, flaxseeds, and chia seeds).
  • Monounsaturated fatty acids (found in olive, avocado, and peanut oils).
  • Fiber (found in minimally processed plant foods).
  • Antioxidants, most B vitamins, and vitamin D.
  • Magnesium and zinc.
  • Garlic, onions, most herbs & spices.

Pro-inflammatory nutrients include:

  • Refined carbohydrates.
  • Cholesterol.
  • Total fat.
  • Saturated fats.
  • Trans fats.

The participants were followed for 3 years, and all new diagnoses of dementia were recorded. The diagnoses were confirmed by a panel of neurologists and neuropsychologists.

Can Your Diet Cause You To Lose Your Mind?

Forgetful Old ManAs described above, the diet of each participant in the study was rated on a 15-point DII (Diet Inflammatory Index) scale ranging from pro-inflammatory to anti-inflammatory. The association of the DII score of the participant’s diets with the onset of dementia was evaluated in two ways.

  • Each one-point increase from an anti-inflammatory diet to a pro-inflammatory diet was associated with a 21% increase in the risk for dementia.
  • In other words, even small changes in your diet can have a significant impact on your risk of developing dementia.

The investigators then divided the participants into three equal-sized groups based on the DII score of their diets.

  • The group with the highest DII scores were 3 times more likely to develop dementia than the group with the lowest DII scores.
  • In other words, a major change in your diet can have a major effect on your risk of developing dementia.

The authors concluded, “In the present study, higher DII scores (indicating greater pro-inflammatory diet potential) were associated with an increased risk for incident dementia [newly diagnosed dementia]. These findings may avail the development of primary dementia strategies through tailored and precise dietary interventions.”

What Is A Mind-Healthy Diet?

Vegan FoodsThis and other studies show that an anti-inflammatory diet is good for the mind. It helps protect us from cognitive decline and dementia. But what does an anti-inflammatory diet look like?

One hint comes from analyzing the diets of participants in this study:

  • Those with the lowest DII scores (most-anti-inflammatory diets) consumed 20 servings of fruit, 19 servings of vegetables, 4 servings of beans or other legumes, and 11 servings of coffee or tea each week. That’s almost 3 servings of fruit and 3 servings of vegetables every day!
  • Those with the highest DII scores (most pro-inflammatory diets) consumed only half as many fruits, vegetables, and legumes.
  • In short, a diet rich in fruits, vegetables, and legumes is a good start.

I have described anti-inflammatory diets in more detail in a previous issue of “Health Tips From the Professor.” Let me summarize that article briefly.

Anti-inflammatory foods include:

  • Colorful fruits and vegetables.
  • Whole grains.
  • Beans and other legumes.
  • Nuts, olive oil, avocados, and other sources of monounsaturated fats.
  • Fatty fish and other sources of omega-3 fatty acids.
  • Herbs and spices.

Pro-inflammatory foods include:

  • Refined carbohydrates, sodas, and sugary foods.
  • Foods high in saturated fats including fatty and processed meats, butter, and high fat dairy products.
  • Foods high in trans fats.
  • French fries, fried chicken, and other fried foods.
  • Foods you are allergic or sensitive food. For example, gluten containing foods are pro-inflammatory only if you are sensitive to gluten.

If your goal is to reduce chronic inflammation and keep your mind sharp as a tack as you age, you should eat more anti-inflammatory foods and less pro-inflammatory foods.

Of course, we don’t just eat random foods, we follow dietary patterns. It should be apparent from what I have Mediterranean Diet Foodscovered above that whole food, primarily plant-based diets are anti-inflammatory. This is true for diets ranging from vegan through semi-vegetarian, to the Mediterranean, DASH, and MIND diets.

All these diets are anti-inflammatory and likely protect the brain from cognitive decline. However, the best evidence for brain protection is for the Mediterranean, DASH, and MIND diets.

  • The Mediterranean and DASH diets have been shown to prevent cognitive decline in multiple studies.
  • The MIND diet is a combination the Mediterranean and DASH diets that was specifically designed to prevent cognitive decline. It has been shown to cut the risk of developing Alzheimer’s disease in half.

What Is A Mind-Healthy Lifestyle?

Diet is just one aspect of a holistic approach for reducing cognitive decline as we age. Other important factors include:

  • Reduce excess body weight.
  • Exercise regularly.
  • Get adequate sleep.
  • Reduce and/or manage stress.
  • Eliminate smoking and reduce alcohol consumption.
  • Socialize with friends and family who support you. Numerous studies have shown that a strong support network reduces dementia risk in the elderly.
  • Keep your brain active. Work crossword puzzles. Learn new things. An active brain is forced to lay down new neural pathways.

The Bottom Line 

Recent studies have suggested that chronic inflammation increases the risk of cognitive decline and dementia as we age. Some causes of chronic inflammation are beyond our control, but others, such as diet, we can control.

Recently, a precise scoring system called the Diet Inflammatory Index (DII) has been developed. This scoring system allows studies to look at the correlation between the inflammatory potential of the diet and cognitive decline.

A recent study enrolled 1,000 participants with an average age of 75 in a 3-year study to determine the impact of diet on cognitive decline. The association of the DII score of the participant’s diets with the onset of dementia was evaluated in two ways.

  • Each one-point increase from an anti-inflammatory diet to a pro-inflammatory diet was associated with a 21% increase in the risk for dementia.
  • In other words, even small changes in your diet can have a significant impact on your risk of developing dementia.

The investigators then divided the participants into three equal-sized groups based on the DII score of their diets.

  • The group with the highest DII scores were 3 times more likely to develop dementia than the group with the lowest DII scores.
  • In other words, a major change in your diet can have a major effect on your risk of developing dementia.

The authors concluded, “In the present study, higher DII scores (indicating greater pro-inflammatory diet potential) were associated with an increased risk for incident dementia [newly diagnosed dementia]. These findings may avail the development of primary dementia strategies through tailored and precise dietary interventions.”

For more details and a description of mind-healthy diets and a mind-healthy lifestyle read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure or prevent any disease.

Do Processed Foods Increase Your Risk Of Diabetes?

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Why Do We Keep Eating Processed Foods?

Fast Food DangersUnless you are Rip Van Winkle and have been asleep for the past 20 years you probably know that the highly processed foods in the typical American diet are bad for your health. But perhaps you didn’t realize just how bad they were.

But first, let’s start with a bit of perspective. Scientists like to be precise. Even healthy foods go through some processing.

  • The oatmeal you ate this morning was either steel-cut or ground. That is processing.
  • The almond butter you put on your whole grain toast this morning was made by roasting and grinding. That is processing.

So, scientists have developed the term “ultra-processed food” to describe the worst of the worse. In short, ultra-processed foods:

  • Usually go through several physical and chemical processes, such as extruding, molding, prefrying, and hydrogenation that can lead to the formation of toxic contaminants. One example you may have heard about recently would be acrylamide in French fries.
  • Typically contain ingredients of no or little nutritive value, such as refined sugar, hydrogenated oils, emulsifiers, artificial sweeteners, thickening agents, and artificial colors. Some of these ingredients have been linked to cancer, heart disease, and premature death.
  • Have long shelf-lives because of added preservatives. This allows migration of chemicals such as bisphenol A from the packaging materials into the food.

Examples of ultra-processed foods include:

  • Sodas
  • Chips
  • Candy and packages of cookies or crackers
  • Most breakfast cereals
  • Boxed cake, cookie, and pancake mix
  • Chicken nuggets and fish sticks
  • Fast food burgers
  • Hot dogs and other processed meats
  • Infant formula
  • Instant noodles
  • Most store-bought ice cream
  • Flavored yogurt

In short, ultra-processed foods include sodas and the junk and convenience foods Americans hold so dear. Even things like infant formula and flavored yogurt make the list.

Evidence of the ill effects of ultra-processed foods on our health is becoming overwhelming. In previous issues of “Health Tips From the Professor” I have shared recent studies that have shown that heavy consumption of ultra-processed foods is linked to increased risk of obesity and cancer. Other studies have linked ultra-processed food consumption with increased risk of depression, heart disease, and premature death.

In this issue of “Health Tips From the Professor” I:

  • Ask the important question, “If we know these foods are so bad for us, why do we still keep eating them?”

How Was The Study Done?

Clinical StudyThe data from this study were taken from an ongoing study in France (the NutriNet-Sante study) looking at associations between nutrition and health. This study began enrolling French adults 18 and older in 2009.

This is a web-based study. Participants are prompted to go to a dedicated website and fill out questionnaires related to things like sex, age, height, weight, smoking status, physical activity, health status, and diet.

With respect to diet, participants filled out a series of 3 nonconsecutive 24-hour dietary records at the time of enrollment and every 6 months. This is a particularly strong feature of this study. Many studies of this type only analyze participant’s diets at the beginning of the study. Those studies have no way of knowing how the participant’s diets may have changed during the study.

Diagnosis of type 2 diabetes for study participants was obtained from the French centralized health records.

The study enrolled 104,708 participants, 20% men and 80% women, and followed them for an average of 6 years. The average age of the participants was 43 years.

Do Processed Foods Increase Your Risk Of Diabetes?

High Blood SugarIn this study the range of ultra-processed foods in the French diet ranged from 7% to 27% (average = 17%). High intake of ultra-processed foods was associated with:

  • Younger participants. Simply put, young people were more likely to drink sodas and eat junk food than older adults.
  • Increased caloric intake. Ultra-processed foods have a higher caloric density than whole, unprocessed foods.
  • No surprise here. Previous studies have shown that ultra-processed food consumption increases the risk of obesity.
  • Poorer diet quality. Again, no surprise. Junk foods tend to crowd healthier foods out of the dirt. Specifically, ultra-processed food consumption was associated with:
    • Higher intake of sugar and salt.
    • Lower intake of fiber.
    • Higher intake of sugary drinks, red and processed meats.
    • Lower intake of whole grains, yogurt, nuts, fruits, and vegetables.

However, even after statistically correcting for all these factors, there was a significant association between ultra-processed food consumption and the onset of type 2 diabetes in the 6-year follow-up period.

  • There was a linear relation between ultra-processed food consumption and the development of type 2 diabetes. Simply put, the more ultra-processed food the participants consumed the more likely they were to be diagnosed with type 2 diabetes.
  • There was a 15% increased risk of developing type 2 diabetes for every 10% increase in ultra-processed food consumption.

The authors concluded:

“In this large observational prospective study, a higher proportion of ultra-processed food in the diet was associated with a higher risk of type 2 diabetes. Even though these results need to be confirmed in other populations and settings, they provide evidence to support efforts by public health authorities to recommend limiting ultra-processed food consumption.”

What Does This Study Mean For You?

Questioning WomanYou might be tempted to say that a 15% increase in the risk of developing diabetes is a small price to pay for continuing to eat the foods you enjoy. However, you should be alarmed by this study. Here is why.

The French diet is much healthier than the American. Remember that ultra-processed foods only comprised 17% of the French Diet. In contrast, a recent survey found that:

  • Ultra-processed foods make up 58% of the average American’s diet.
  • Ultra-processed foods account for 90% of the added sugar in our diet.

It is no wonder that obesity and diabetes are reaching epidemic proportions in our country.

You might also be tempted to think that you can just take some medications and live with type 2 diabetes. However, you should think of type 2 diabetes as a gateway disease. It increases your risk of heart disease, high blood pressure, Alzheimer’s disease, kidney damage, and neuropathy, just to name a few. These are diseases that make your life miserable and ultimately kill you.

More importantly, type 2 diabetes is completely reversible if you catch it early enough. Just lose some weight, exercise more, give up the ultra-processed foods, and eat a healthy diet. I recommend a whole food, primarily plant-based diet.

Why Do We Keep Eating Processed Foods?

Fast FoodsWe all know that ultra-processed foods are bad for us. Study after study show that they make us sick. They kill us prematurely. And, unlike most topics in the field of nutrition, this is not controversial.

For example, there have been lots of bizarre diets that have come and gone over the years. There have been books written on “The Steak Lover’s Diet” and “The Drinking Man’s Diet”. But nobody has written a book on “The Junk Food Lover’s Diet”. It simply would not be believable.

So why do we Americans keep eating such unhealthy foods. Part of the answer is physiological. A preference for sweet, salty, and fatty foods is hardwired into our brain. That’s because they had great survival value in prehistoric times.

If we think back to the time when we were hunters and gatherers:

  • Fruits are healthy foods. They are a great source of antioxidants, phytonutrients, and fiber, but there were no orchards or grocery stores back then. We had to search for fruits in the wild. Our desire for sweet tasting foods provided the motivation to seek them out.
  • Game was seasonal and sometimes scarce. We had to be prepared to go for days or weeks without eating except for the leaves and roots we could gather. Our bodies are designed to store fat as the primary energy source to get us through the lean times. Our preference for fatty foods encouraged us to store as much fat as possible in times of plenty so we would be prepared for times of scarcity.
  • If we fast forward to our early recorded history, salt was scarce. It was worth its weight in gold. Yet some salt is essential for life. Our preference for salty foods encouraged us to search out supplies of salt.

Unfortunately, the food industry has weaponized these food preferences to create the ultra-processed foods we know today. Their ads entice us by associating these foods with youth and good times. And ultra-processed foods have become ubiquitous. There are fast food restaurants on almost every street corner and shopping mall in the country.

Fortunately, we do not have to let the food industry destroy our health. We can retrain our taste buds to appreciate the sweetness of fresh fruits and vegetables. We can substitute healthy fats for the kinds of fat found in most ultra-processed foods. We can also retrain our taste buds to appreciate herbs and spices with just a pinch of salt.

The Bottom Line

Ultra-processed foods, such as sodas, junk foods, and convenience foods have become the biggest food group in the American diet. A recent study found:

  • Ultra-processed foods make up 58% of the average American’s diet.
  • Ultra-processed foods account for 90% of the added sugar in our diet.

That is scary because ultra-processed foods are deadly. Previous studies have shown that consumption of ultra-processed foods is linked to obesity, heart disease, cancer, and Alzheimer’s disease.

The study discussed this week looked at the association between ultra-processed food consumption and type 2 diabetes. It showed:

  • There was a linear relation between ultra-processed food consumption and the development of type 2 diabetes. Simply put, the more ultra-processed food the participants consumed the more likely they were to be diagnosed with type 2 diabetes.
  • There was a 15% increased risk of developing type 2 diabetes for every 10% increase in ultra-processed food consumption.

You might be tempted to think that you can just take some medications and live with type 2 diabetes. However, you should think of type 2 diabetes as a gateway disease. It increases your risk of heart disease, high blood pressure, Alzheimer’s disease, kidney damage, and neuropathy, just to name a few. This are diseases that make your life miserable and ultimately kill you.

More importantly, type 2 diabetes is completely reversible if you catch it early enough. Just lose some weight, exercise more, give up the ultra-processed foods, and eat a healthy diet. I recommend a whole food, primarily plant-based diet.

For more details and a discussion of why Americans continue to eat ultra-processed food even though we know it is bad for us, read the article above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

How Much DHA Is Needed To Prevent Alzheimer’s

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What Are We Missing?

Cognitive-DeclineWe are an aging population. As such, issues like cognitive decline, dementia, and Alzheimer’s Disease are of increasing concern. After all, what is the good of reaching your “Golden Years” with a healthy body if you lose your mind?

The ability of the omega-3 fatty acids DHA and EPA to reduce the risk of cognitive decline, dementia, and Alzheimer’s Disease is controversial. Some studies say yes. Others say no.

When studies are conflicting most experts simply conclude the treatment is unproven. I am sympathetic to that viewpoint, but I first like to ask the questions: “Why are the studies conflicting? What are we missing?”

I start by evaluating the strengths and weaknesses of the individual studies.

  • If the studies claiming the treatment works are weak, I am content to “join the chorus” and consider the treatment unproven.
  • If the studies claiming the treatment doesn’t work are weak, I am a strong advocate for more well-designed studies before we conclude that the treatment doesn’t work.
  • If both the “pro” and “con” studies are strong, I want to ask, “What are we missing?”

This is the situation with studies asking whether DHA reduces the risk of Alzheimer’s Disease and other forms of cognitive decline as we age.

  • Association studies show that greater intake and higher blood levels of the omega-3 fatty acids EPA and DHA are associated with lower risk of Alzheimer’s Disease.
  • However, most placebo-controlled clinical trials with either DHA alone or DHA + EPA have come up negative. Of course, one can always argue that most of the placebo-controlled clinical trials were too short or too small to show a statistically significant effect. But, my question remains, “What else are we missing?”

One recent study has provided an interesting clue. The authors of the study postulated that B vitamins were required to deliver omega-3 fatty acids to the brain, and their study showed that omega-3 fatty acids were only effective at decreasing the risk of cognitive decline in subjects who also had optimal B vitamin status.

In other words, this study suggested that studies on the effect of omega-3 supplementation and risk of developing Alzheimer’s are doomed to failure if a significant percentage of the subjects have sub-optimal B vitamin status.

The authors of the current study ( IC Arellanes et al, EBioMedicine, doi.org/10.1016/j.ebiom.2020.102883) proposed two additional hypotheses for the negative results of previous clinical trials and designed an experiment to test their hypotheses. Their hypotheses were:

  • Uptake of DHA and EPA by the brain is very inefficient, and previous studies have not used sufficient doses of DHA or DHA plus EPA to see a significant effect on cognitive impairment.
  • The APOE4 gene further decreases the uptake of DHA and EPA by the brain.

Before I describe how the study was done, I should probably provide some context by describing how DHA and EPA reach the brain and the role of the apoE protein in the process. It’s time for my favorite topic: “Biochemistry 101”.

Biochemistry 101: What Does The ApoE Protein Do?

ProfessorIf you have ever tried to mix oil and water, it should come as no surprise to you that fats, including DHA and EPA, and cholesterol are not water soluble. That leaves our bodies with a dilemma. How do they get the fat and cholesterol we eat to pass through our bloodstream and get to our cells, where they are needed?

Our body’s solution is to incorporate the fat and cholesterol into particles called lipoproteins. Lipoprotein particles sequester the fat and cholesterol in their interior and surround them with water soluble phospholipids and proteins. Lipoproteins allow our bodies to transport fat and cholesterol through our bloodstream to the tissues that need them.

The next question, of course, is how the lipoproteins know which cells need the fat and cholesterol. This is where apoproteins like apoE come into play. We can think of the apoE protein as a zip code that directs lipoproteins to cells with an apoE receptor.

Our nervous system contains lots of apoE receptors, and binding of the apoE protein to its receptor is instrumental in the delivery of DHA, EPA, and cholesterol to our nervous system.

DHA and cholesterol are both important for brain health. That is because they are major components of the myelin sheath that wraps around our neurons and protects them. EPA may also be important for brain health because its anti-inflammatory effects are thought to prevent the accumulation of the amyloid plaques that are the hallmark of late-onset Alzheimer’s Disease.

There are three major versions of the APOE gene, APOE2, APOE3, and APOE4. Each of them plays slightly different roles in our body. However, it is the APOE4 version that is of interest to us. About 25% of us have the APOE4 version of the APOE gene and it increases our risk of developing Alzheimer’s Disease by a factor of two.

We do not know why this is, but one hypothesis is that lipoproteins with the apoE4 protein have more difficultly delivering much needed DHA, EPA, and cholesterol to the brain. This is one of the hypotheses that the authors set out to study.

How Was The Study Done?

Clinical StudyThere are two things you should know about this study.

  • This was a pilot study designed to test the author’s hypotheses and allow them to choose the correct dose of DHA to use for a subsequent study designed to test whether high-dose DHA can reduce the risk of developing Alzheimer’s Disease.
  • This was a very small study. That’s because the only way to determine how much DHA and EPA reaches the nervous tissue is to perform a lumbar puncture and obtain cerebrospinal fluid at baseline and again at the end of the study. Lumbar punctures are both painful and a bit risky. They were lucky to find 26 individuals who consented to the lumbar punctures.

This was a double-blind, placebo controlled clinical study.

  • Half the subjects were given 2,152 mg/day of DHA for 6 months, and half were given a daily placebo consisting of corn and soybean oil for 6 months.
  • Because previous studies have suggested that B vitamins were important for DHA and EPA uptake by nervous tissue, all subjects received a B vitamin supplement.
  • Levels of DHA and EPA were measured in both plasma and cerebrospinal fluid at baseline and again at the end of 6 months. Note: The subjects were only supplemented with DHA. The investigators were relying on the body’s ability to convert DHA into EPA.
  • All subjects were screened for APOE4

Other important characteristics of the study subjects were:

  • Average age was 69. They were 80% female.
  • All of them had a close family member who had previously been diagnosed with dementia, but none of them had been diagnosed with cognitive impairment at the time of entry into the study.
  • Around 45% of them had the APOE4 version of the APOE.

In other words, none of them currently had dementia, but most were at high risk of developing dementia.

How Much DHA Is Needed To Prevent Alzheimer’s?

fish and fish oilAfter 6 months of supplementing with over 2,000 mg/day of DHA:

  • DHA levels in the blood had increased by 200%.
  • However, DHA levels in cerebrospinal fluid had increased by only 28%.
  • Moreover, DHA levels in cerebrospinal fluid were 40% lower in subjects who had the APOE4 gene compared to subjects with the APOE2 and APOE3

EPA levels in cerebrospinal fluid averaged about 15-fold lower than DHA levels. When they looked at the effect of DHA supplementation on EPA levels.

  • EPA levels in plasma had increased by 50%.
  • EPA levels in cerebrospinal fluid had increased by 43%.
  • EPA levels in cerebrospinal fluid were 3-fold lower in subjects who had the APOE4 gene compared to subjects with the APOE2 and APOE3

The authors concluded:

“We observed only a modest (28%) increase in cerebrospinal fluid DHA levels with 2152 mg per day of DHA supplementation. This finding has implications for past clinical trials that have used lower doses (e.g. 1 g daily of DHA supplements or less) and were overwhelmingly negative. Using lower doses of omega-3 supplements may have resulted in limited omega-3 brain delivery.”

“Another aspect affecting the response to DHA supplementation is APOE4 status. Subjects with the APOE4 gene showed lower DHA levels and significantly lower EPA levels than subjects with other APOE genes”.

“In summary, our study suggests that higher doses of omega-3 fatty acids (2 or more g of DHA) are needed to ensure adequate brain delivery, particularly in APOE4 carriers…Past low dose (1 g per day or less) omega-3 supplementation trials in dementia prevention may not have provided adequate brain levels to fully evaluate the efficacy of omega-3 supplementation on cognitive outcomes.”

Based on the results from this study the authors are currently testing the effect of B vitamins and high dose DHA supplementation on cerebrospinal fluid fatty acid levels, brain imaging, and cognitive outcomes in a larger ongoing clinical trial.

What Does This Study Mean For You?

Questioning ManThe ability of the omega-3 fatty acids DHA and EPA to reduce the risk of cognitive decline, dementia, and Alzheimer’s Disease is confusing. Studies disagree.

In situations like this, most experts dismiss the hypothesis as “unproven”. However, I like to ask, “What are we missing?”

One recent study provided a clue. It suggested that omega-3s and B vitamins were interdependent. We need both to reduce cognitive decline. However, that might not be the complete answer.

This study gave both DHA and B vitamins to subjects and discovered another interesting clue. The study suggests we may not have been giving subjects enough omega-3s to see a significant effect on cognitive decline.

Let me start by saying this study did not test whether or not DHA supplementation prevents cognitive decline, dementia, and Alzheimer’s Disease. Nor does it tell us how much DHA is needed to prevent Alzheimer’s Disease, other than to show that anything less than 2 g per day is likely to be inadequate. 

However, the study did make two important advances:

#1: It showed just how difficult it is to deliver adequate amounts of DHA and EPA to the brain. This is important because it shows:

  • Most previous studies have not used high enough doses of DHA or DHA plus EPA to evaluate the effect of omega-3 fatty acids on cognitive decline. Those studies were not simply negative. They were doomed to failure. The studies were worthless.
  • That means we should stop saying that the ability of omega-3s to prevent cognitive decline and diseases like Alzheimer’s is unproven. Instead, we should say that hypothesis has not adequately been tested.
  • That also means future studies of the ability of DHA to reduce the risk of cognitive decline, dementia, and/or Alzheimer’s will need to use much higher doses or a better delivery system to get adequate amounts of DHA and EPA into the brain.

#2: It showed that the APOE4 gene significantly decreases the ability of the brain to accumulate DHA and EPA. This has several important implications.

  • Because both DHA and EPA are vital for brain health, this may explain why the APOE4 gene increases the risk of Alzheimer’s Disease.
  • It also means those at highest risk for Alzheimer’s Disease are the ones who are most likely to have difficulties accumulating DHA and EPA in their brain.
  • Once again, it means future studies of the ability of supplemental DHA to reduce the risk of Alzheimer’s Disease will need to use much higher doses of DHA.

The Bottom Line

We are an aging population. As such, issues like cognitive decline, dementia, and Alzheimer’s Disease are of increasing concern. After all, what is the good of reaching your “Golden Years” with a healthy body if you lose your mind?

The ability of the omega-3 fatty acids DHA and EPA to reduce the risk of cognitive decline, dementia, and Alzheimer’s Disease is controversial.

  • Association studies show that greater intake and higher blood levels of the omega-3 fatty acids EPA and DHA are associated with lower risk of Alzheimer’s Disease.
  • However, most placebo-controlled clinical trials with either DHA alone or DHA + EPA have come up negative.

In situations like this, most experts dismiss the hypothesis as “unproven”. However, I like to ask, “What are we missing?”

One recent study provided a clue. It suggested that omega-3s and B vitamins were interdependent. We need optimal amounts of both to reduce dementia. However, that might not be the complete answer.

This study gave both DHA and B vitamins to participants and discovered another interesting clue. The study suggests we may not have been giving subjects enough omega-3s to see a significant effect on cognitive decline.

The authors of the study hypothesized:

  • Uptake of DHA and EPA by the brain is very inefficient, and previous studies have not used sufficient doses of DHA or DHA plus EPA to see a significant effect on cognitive impairment.
  • The APOE4 gene, which is known to increase the risk of Alzheimer’s Disease, further decreases the uptake of DHA and EPA by the brain.

Their study confirmed their hypotheses and made two important advancements:

#1: It showed just how difficult it is to deliver adequate amounts of DHA and EPA to the brain. This is important because it shows:

  • Most previous studies have not used high enough doses of DHA or DHA plus EPA to evaluate the effect of omega-3 fatty acids on cognitive decline. Those studies were not simply negative. They were doomed to failure. The studies were worthless.
  • That means we should stop saying that the ability of omega-3s to prevent cognitive decline and diseases like Alzheimer’s is unproven. Instead, we should say that hypothesis has not adequately been tested.
  • That also means future studies of the ability of DHA to reduce the risk of cognitive decline, dementia, and/or Alzheimer’s will need to use much higher doses or a better delivery system to get adequate amounts of DHA and EPA into the brain.

#2: It showed that the APOE4 gene significantly decreases the ability of the brain to accumulate DHA and EPA. This has several important implications.

  • Because both DHA and EPA are vital for brain health, this may explain why the APOE4 gene increases the risk of Alzheimer’s Disease.
  • It also means those at highest risk for Alzheimer’s Disease are the ones who are most likely to have difficulties accumulating DHA and EPA in their brain.
  • Once again, it means future studies of the ability of supplemental DHA to reduce the risk of Alzheimer’s Disease will need to use much higher doses of DHA.

Based on the results from this study the authors are currently testing the effect of B vitamins and high dose DHA supplementation on DHA and EPA levels in the brain, brain imaging, and cognitive outcomes in a larger ongoing clinical trial.

For more details, read the article above. For a better understanding of the roles of DHA, EPA, and the APOE gene in brain health, you may want to read my “Biochemistry 101” section above.

These statements have not been evaluated by the Food and Drug Administration. This information is not intended to diagnose, treat, cure, or prevent any disease.

 

Health Tips From The Professor