Does Olive Oil Help You Live Longer?

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?

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.

How Much DHA Is Needed To Prevent Alzheimer’s

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.

 

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