Are Nuts Good For Your Heart?

Which Nuts Are Best?

Last week I shared an important study about the benefits of replacing some of the animal protein in your diet with plant protein from whole grains. In case you have forgotten, the study showed replacing just 15 grams of the animal protein in your diet with an equivalent amount of protein from whole grains significantly decreased the risk of premature death from cardiovascular disease, stroke, and from all causes.

This was an important study because whole grains have been maligned in recent years. Low carb diets, keto diets, paleo diets, and low-lectin diets all recommend cutting whole grains out of your diet. Dr. Strangelove and his friends have been telling us to avoid whole grains, and too many Americans have been doing just that.

The study I shared last week reminds us that whole grains are good for our hearts. They are a great source of antioxidants, B vitamins, minerals, and phytonutrients. More importantly, they contain a unique type of fiber called resistant starch that supports the growth of heart-healthy gut bacteria. There are a few other foods that are a good source of resistant starch, but they are also on Dr. Strangelove’s “naughty list” of foods to avoid.

Unfortunately, you might have come away from last week’s article thinking that other plant protein sources, like beans, legumes, nuts, and seeds, weren’t important for reducing your risk of heart disease. However, the fact that they didn’t reduce the risk of premature death from heart disease in that study was likely an artifact of the way the study was designed.

The study asked what happens when you change 15 grams of the protein in your diet from red meat protein to different kinds of plant protein. That question was easy to answer for grains because they are a major source of protein in the American diet. However, Americans don’t get enough protein from either beans and legumes or nuts and seeds to provide a statistically valid answer to that question.

To correct any misconceptions from last week’s article I thought it might be valuable to review a study (M Guasch-Ferré et al, Journal Of The American Journal Of Cardiology, 70: 2519-2532) from a few years ago that looked at the effect of nut consumption on the risk of heart disease.

How Was The Study Done?

Clinical StudyThis study started by combining the data from three major clinical trials:

  • The first Nurse’s Health Study, which ran from 1980 to 2012,
  • The second Nurse’s Health Study, which ran from 1991-2013, and
  • The Health Professional’s Follow-Up Study, which ran from 1986-2012.

These studies combined enrolled 169,310 women and 41,526 men and followed them for an average of 32 years. All the participants were free of heart disease and cancer at the time they were enrolled. The design of these studies was extraordinary.

  • A detailed food frequency questionnaire was administered every 4 years. This allowed the investigators to calculate cumulative averages of all dietary variables, including nuts. This assured that the effects of nut consumption and diet represented the participant’s average diet over the 32-year duration of the study, not just their diet when they entered the study.
  • Participants also filled out questionnaires that captured information on disease diagnosis, disease risk factors, medicines taken, weight, and lifestyle characteristics every 2 years with follow-up rates >90%. This allowed the investigators to measure the onset of heart disease for each participant during the study. More importantly, 32 years is long enough to measure the onset of diseases like heart disease, which requires decades to develop.
  • The primary endpoint of the study was “cardiovascular disease”, which the investigators defined as fatal and non-fatal heart attacks, fatal and non-fatal strokes, and deaths from all types of heart disease. During this study, 14,136 participants developed cardiovascular disease. This was a large enough number for a detailed statistical analysis of the data.
  • Secondary endpoints were heart disease (fatal and non-fatal heart attacks) and stroke (fatal and non-fatal strokes).

Are Nuts Good For Your Heart?

strong heartWhen the authors compared people who consumed 5 or more one ounce servings of nuts per week with people who never or almost never consumed nuts, they found that nut consumption decreased:

  • Cardiovascular disease by 14%.
  • Heart attacks by 20%.
  • Strokes by a non-significant 2%.

This part of the study merely confirms what other studies have shown. What makes this study unique is that it identifies the relative heart health benefits of different kinds of nuts.

Which Nuts Are Best?

Nuts are an excellent source of vitamins, minerals, phytonutrients, and fiber. But what makes them particularly heart healthy is the healthy fats they provide.

  • Peanuts (which are actually legumes rather than true nuts) are rich in monounsaturated fats.
  • Tree nuts in general are an excellent source of polyunsaturated fats.

    Walnuts
  • Walnuts are particularly rich in omega-3 polyunsaturated fats.

When they looked at individual nuts:

  • Consuming a serving of peanuts (35 peanuts) 2 or more times per week decreased:
    • Cardiovascular disease by 13%.
    • Heart attacks by 15%.
    • Stroke by 10%.
    • Peanut butter had no effect on cardiovascular outcomes, probably because many commercial brands of peanut butter add saturated fats to reduce separation of the oil and make their product creamier.
  • Consuming a serving of tree nuts (12-15 nuts) 2 or more times per week decreased:
    • Cardiovascular disease by 15%.
    • Heart attacks by 23%.
  • Consuming a serving of walnuts (14 walnut halves) one or more times per week decreased:
    • Cardiovascular disease by 19%.
    • Heart attacks by 21%.
    • Stroke by 17%.

In case you missed it, walnuts were the superstars of the nut family. One serving/week of walnuts was more effective than two or more servings/week of peanuts or other tree nuts at reducing the risk of heart attacks, stroke, and overall cardiovascular disease. This is probably because walnuts are a particularly good source of omega-3 fats.

[Professor’s note: I include a serving of walnuts with my breakfast every morning.]

The authors concluded: “Findings from 3 large prospective cohort studies indicate that frequent intake of nuts, tree nuts, peanuts, and walnuts was associated with a lower risk of cardiovascular disease, independently from other cardiovascular risk, lifestyle, and dietary factors. Our findings support recommendations of increasing the intake of a variety of nuts as part of healthy dietary patterns to reduce the risk of chronic diseases in the general population.”

What Does This Study Mean For You?

Questioning WomanI have consistently shared the evidence that primarily plant-based diets are associated with the best long-term health outcomes, especially when we look at chronic diseases like heart disease, diabetes, and cancer.

I have also consistently shared the message that “We have 5 food groups for a reason”. All 5 food groups are part of a healthy diet.

Unfortunately, Dr. Strangelove and his friends have been telling us that whole grains are bad for us. We should eliminate them from our diet. And too many Americans have been following that advice. That’s why last week’s “Health Tips From the Professor” article reviewed the evidence for heart health benefits from whole grain consumption.

The situation with nuts and seeds is a little different. Most people recognize them as healthy. They just don’t eat enough of them. That’s why this week’s article emphasized the heart health benefits from nut consumption. Here is the take home message I hope you get from this article:

  • Two or more servings/week of peanuts or tree nuts significantly reduces your risk of heart attack, stroke, and other cardiovascular diseases.
  • Walnuts are the superstars of the nut family. One serving/week of walnuts (14 walnut halves) was more effective at reducing the risk of heart attack, stroke, and other cardiovascular diseases than two or more servings/week of the other nuts.
  • This study was based on unprocessed nuts. Nuts coated with salt, sugar, or chocolate probably don’t qualify as heart healthy.
  • Processed foods made from nuts also may not be heart healthy. For example, peanut butter had no effect at decreasing heart disease risk in this study.

Finally, in closing I want to revisit my statement that “We have 5 food groups for a reason”.

  • The studies I shared this week and last week show that whole grains and nuts are important components of a heart healthy diet. But it doesn’t stop there.
  • All plant food groups are part of a heart healthy diet. In previous issues of “Health Tips From the Professor” I have shared studies showing beans, fruits, and vegetables are all important components of a heart healthy diet.
  • I have also shared recent studies showing that adding small amounts of eggs and dairy may make a vegetarian diet more heart healthy.
  • Finally, I have shared a study showing that small amounts of red meat can be heart healthy in the context of a primarily plant-based diet such as the Mediterranean diet.

Of course, we are talking about whole food diets. If you include sodas and highly processed foods in the diet, all bets are off.

The Bottom Line

I have consistently shared the evidence that primarily plant-based diets are associated with the best long-term health outcomes, especially when we look at chronic diseases like heart disease, diabetes, and cancer.

I have also consistently shared the message that “We have 5 food groups for a reason”. All 5 food groups are part of a healthy diet.

Unfortunately, Dr. Strangelove and his friends have been telling us that whole grains are bad for us. We should eliminate them from our diet. And too many Americans have been following that advice. That’s why last week’s “Health Tips From the Professor” article reviewed the evidence for heart health benefits from whole grain consumption.

The situation with nuts and seeds is a little different. Most people recognize them as healthy. They just don’t eat enough of them. That’s why this week’s article emphasized the heart health benefits of nut consumption. Here is the take home message I hope you get from this article:

  • Two or more servings/week of peanuts or tree nuts significantly reduces your risk of heart attack, stroke, and other cardiovascular diseases.
  • Walnuts are the superstars of the nut family. One serving/week of walnuts (14 walnut halves) was more effective at reducing the risk of heart attack, stroke, and other cardiovascular diseases than two or more servings/week of the other nuts.
  • This study was based on unprocessed nuts. Nuts coated with salt, sugar, or chocolate probably don’t qualify as heart healthy.
  • Processed foods made from nuts also may not be heart healthy. For example, peanut butter had no effect at decreasing heart disease risk in this study.

Finally, in closing I want to revisit my statement that “We have 5 food groups for a reason”.

  • The studies I shared this week and last week show that whole grains and nuts are important components of a heart healthy diet. But it doesn’t stop there.
  • All plant food groups are part of a heart healthy diet. In previous issues of “Health Tips From the Professor” I have shared studies showing beans, fruits, and vegetables are all important components of a heart healthy diet.
  • I have also shared recent studies showing that adding small amounts of eggs and dairy may make a vegetarian diet more heart healthy.
  • Finally, I have shared a study showing that small amounts of red meat can be heart healthy in the context of a primarily plant-based diet such as the Mediterranean diet.

Of course, we are talking about whole food diets. If you include sodas and highly processed foods in the diet, all bets are off.

For more details, 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 You Improve Your Healthspan?

Can You Live Healthier, Longer?

Ever since Ponce de Leon led an expedition to the Florida coast in 1513, we have been searching for the mythical “Fountain Of Youth”. What does that myth mean?

Supposedly, just by immersing yourself in that fountain you would be made younger. You would experience all the exuberance and health you enjoyed when you were young. There have been many snake oil remedies over the years that have promised that. They were all frauds.

But what if you had it in your power to live longer and to retain your youthful health for most of those extra years. The ability to live healthier longer is something that scientists call “healthspan”. But you can think of it as your personal “Fountain Of Youth”.

Where are we as a nation? Americans ranked 53rd in the world for life expectancy. We have the life expectancy of a third-world country. We are in sore need of a “Fountain Of Youth”.

That is why I decided to share two recent studies from the prestigious Harvard T.H. Chan School of Public Health with you today.

How Were The Studies Done?

Clinical StudyThese studies started by combining the data from two major clinical trials:

  • The Nurse’s Health Study, which ran from 1980 to 2014.
  • The Health Professional’s Follow-Up Study, which ran from 1986-2014.

These two clinical trials enrolled 78,865 women and 42,354 men and followed them for an average of 34 years. During this time there were 42,167 deaths. All the participants were free of heart disease, type 2 diabetes, and cancer at the time they were enrolled. Furthermore, the design of these clinical trials was extraordinary.

  • A detailed food frequency questionnaire was administered every 2-4 years. This allowed the investigators to calculate cumulative averages of all dietary variables.
  • Participants also filled out questionnaires that captured information on disease diagnosis every 2 years with follow-up rates >90%. This allowed the investigators to measure the onset of disease for each participant during the study. More importantly, 34 years is long enough to measure the onset of diseases like heart disease, diabetes, and cancer – diseases that require decades to develop.
  • The questionnaires also captured information on medicines taken and lifestyle characteristics such as body weight, exercise, smoking and alcohol use.
  • For analysis of diet quality, the investigators use something called the “Alternative Healthy Eating Index”. [The original Healthy Eating Index was developed about 10 years ago based on the 2010 “Dietary Guidelines for Americans”. Those guidelines have since been updated, and the “Alternative Healthy Eating Index” is based on the updated guidelines.] You can calculate your own Alternative Healthy Eating Index below, so you can see what is involved.
  • Finally, the investigators included five lifestyle-related factors – diet, smoking, physical activity, alcohol consumption, and BMI (a measure of obesity) – in their estimation of a healthy lifestyle. Based on the best available evidence, they defined “low-risk” in each of these categories. Study participants were assigned 1 point for each low-risk category they achieved. Simply put, if they were low risk in all 5 categories, they received a score of 5. If they were low risk in none of the categories, they received a score of 0.
  • Low risk for each of these categories was defined as follows:
    • Low risk for a healthy diet was defined as those who scored in the top 40% in the Alternative Healthy Eating Index.
    • Low risk for smoking was defined as never smoking.
    • Low risk for physical activity was defined as 30 minutes/day of moderate or vigorous activities.
    • Low risk for alcohol was defined as 0.5-1 drinks/day for women and 0.5-2 drinks/day for men.
    • Low risk for weight was defined as a BMI in the healthy range (18.5-24.9 kg/m2).

Can You Live Healthier Longer?

Older Couple Running Along BeachThe investigators compared participants who scored as low risk in all 5 categories with participants who scored as low risk in 0 categories (which would be typical for many Americans). For the purpose of simplicity, I will refer to people who scored as low risk in 5 categories as having a “healthy lifestyle” and those who scored as low risk in 0 categories as having an “unhealthy lifestyle”.

The results of the first study were:

  • Women who had had a healthy lifestyle lived 14 years longer than women with an unhealthy lifestyle (estimated life expectancy of 93 versus 79).
  • Men who had a healthy lifestyle lived 12 years longer than men with an unhealthy lifestyle (estimated life expectancy was 87 versus 75).
  • It was not necessary to achieve a perfect lifestyle. Life expectancy increased in a linear fashion for each low-risk lifestyle behavior achieved.

The authors of the study concluded: “Adopting a healthy lifestyle could substantially reduce premature mortality and prolong life expectancy in US adults. Our findings suggest that the gap in life expectancy between the US and other developed countries could be narrowed by improving lifestyle factors.”

The results of the second study were:

  • Women who had a healthy lifestyle lived 11 years longer free of diabetes, heart disease, and cancer than women who had an unhealthy lifestyle (estimated disease-free life expectancy of 85 years versus 74 years).
  • Men who had a healthy lifestyle lived 8 years longer free of diabetes, heart disease, and cancer than men who had an unhealthy lifestyle (estimated disease-free life expectancy of 81 years versus 73 years).
  • Again, disease-free life expectancy increased in a linear fashion for each low-risk lifestyle behavior achieved.

The authors concluded: “Adherence to a healthy lifestyle at mid-life [They started their analysis at age 50] is associated with a longer life expectancy free of major chronic diseases. Our findings suggest that promotion of a healthy lifestyle would help reduce healthcare burdens through lowering the risk of developing multiple chronic diseases, including cancer, cardiovascular disease, and diabetes, and extending disease-free life expectancy.”

Can You Improve Your Healthspan?

Questioning ManI posed the question at the beginning of this article, “Can you improve your healthspan?” These two studies showed that you can improve both your life expectancy and your disease-free life expectancy. So, the answer to the original question appears to be, “Yes, you can improve your healthspan. You can create your personal “Fountain of Youth.”

However, as a nation we appear to be moving in the wrong direction. The percentage of US adults adhering to a healthy lifestyle has decreased from 15% in 1988-1992 to 8% in 2001-2006.

The clinical trials that these studies drew their data from were very well designed, so these are strong studies. However, like all scientific studies, they have some weaknesses, namely:

  • They looked at the association of a healthy lifestyle with life expectancy and disease-free life expectancy. Like all association studies, they cannot prove cause and effect.
  • The clinical trials they drew their data with included mostly Caucasian health professionals. The results may differ with different ethnic groups.
  • These studies did not look at the effect of a healthy lifestyle on the onset of Alzheimer’s disease and other forms of dementia. However, other studies have shown that people who were low risk for each of the 5 lifestyle factors (diet, exercise, body weight, smoking, and alcohol use) individually have a reduced risk of developing Alzheimer’s and/or dementia.

Finally, I know you have some questions, and I have answers.

Question: What about supplementation? Will it also improve my healthspan?

Answer: When the investigators analyzed the data, they found that those with the healthiest lifestyles were also more likely to be taking a multivitamin. So, they attempted to statistically eliminate any effect of supplement use on the outcomes. That means these studies cannot answer that question.

However, if you calculate your Alternate Healthy Eating Index below, you will see that most of us fall short of perfection. Supplementation can fill in the gaps.

Question: I cannot imagine myself reaching perfection in all 5 lifestyle categories? Should I even try to achieve low risk in one or two categories?

Answer: The good news is that there was a linear increase in both life expectancy and disease-free life expectancy as people went from low-risk in one category to low-risk in all 5 categories. I would encourage you to try and achieve low risk status in as many categories as possible, but very few of us, including me, achieve perfection in all 5 categories.

Question: I am past 50 already. Is it too late for me to improve my healthspan?

Answer: Diet and some of the other lifestyle behaviors were remarkably constant over 34 years in both the Nurse’s Health Study and the Health Professional’s Follow-Up Study. That means that the lifespan and healthspan benefits reported in these studies probably resulted from adhering to a healthy lifestyle for most of their adult years.

However, it is never too late to start improving your lifestyle. You may not achieve the full benefits described in these studies, but you still can add years and disease-free years to your life.

How To Calculate Your Alternative Healthy Eating Index

You can calculate your own Alternative Healthy Eating Index score by simply adding up the points you score for each food category below.

Vegetables

Count 2 points for each serving you eat per day (up to 5 servings).

One serving = 1 cup green leafy vegetables or ½ cup for all other vegetables.

Do not count white potatoes or processed vegetables like French fries or kale chips.

Fruits

Count 2½ points for each serving you eat per day (up to 4 servings).

One serving = 1 piece of fruit or ½ cup of berries.

          (do not count fruit juice or fruit incorporated into desserts or pastries). 

Whole Grains

Count 2 points for each serving you eat per day (up to 5 servings).

One serving = ½ cup whole-grain rice, bulgur and other whole grains, cereal, and pasta or 1 slice of bread.

(For processed foods like pasta and bread, the label must say 100% whole grain).

Sugary Drinks and Fruit Juice

Count 10 points if you drink 0 servings per week.

Count 5 points for 3-4 servings per week (½ serving per day).

Count 0 points for 7 or more servings per week (≥1 serving per day).

One serving = 8 oz. fruit juice, sugary soda, sweetened tea, coffee drink, energy drink, or sports drink.

Nuts, Seeds and Beans

Count 10 points if you eat 7 or more servings per week (≥1 serving per day).

Count 5 points for 3-4 servings per week (½ serving per day).

Count 0 points for 0 servings per week.

One serving = 1 oz. nuts or seeds, 1 Tbs. peanut butter, ½ cup beans, 3½ oz. tofu.

Red and Processed Meat

Count 10 points if you eat 0 servings per week.

Count 7 points for 3-4 servings per week (½ serving per day).

Count 3 points for 3 servings per week (1 serving per day).

Count 0 points for ≥1½ servings per day.

One serving = 1½ oz. processed meats (bacon, ham, sausage, hot dogs, deli meat)

          Or 4 oz. red meat (steak, hamburger, pork chops, lamb chops, etc.)

Seafood

Count 10 points if you eat 2 servings per week.

Count 5 points for 1 serving per week.

Count 0 points for 0 servings per week.

1 serving = 4 oz.

Now that you have your total, the scoring system is:

  • 41 or higher is excellent
  • 37-40 is good
  • 33-36 is average (remember that it is average to be sick in this country)
  • 28-32 is below average
  • Below 28 is poor

Finally, for the purposes of these two studies, a score of 37 or higher was considered low risk.

The Bottom Line

Two recent studies have developed a healthy lifestyle score based on diet, exercise, body weight, smoking, and alcohol use. When they compared the effect of lifestyle on both lifespan (life expectancy) and healthspan (disease-free life expectancy), they reported:

  • Women who had had a healthy lifestyle lived 14 years longer than women with an unhealthy lifestyle.
  • Men who had a healthy lifestyle lived 12 years longer than men with an unhealthy lifestyle.
  • Women who had a healthy lifestyle lived 11 years longer free of diabetes, heart disease, and cancer than women had an unhealthy lifestyle.
  • Men who had a healthy lifestyle lived 8 years longer free of diabetes, heart disease, and cancer than men who had an unhealthy lifestyle.
  • It is not necessary to achieve a perfect lifestyle. Lifespan and healthspan increased in a linear fashion for each low-risk lifestyle behavior (diet, exercise, body weight, smoking, and alcohol use) achieved.
  • These studies did not evaluate whether supplement use also affects healthspan.
    • However, if you calculate your diet with the Alternate Healthy Eating Index they use (see above), you will see that most of us fall short of perfection. Supplementation can fill in the gaps.

The authors concluded: “Our findings suggest that promotion of a healthy lifestyle would help reduce healthcare burdens through lowering the risk of developing multiple chronic diseases, including cancer, cardiovascular disease, and diabetes, and extending disease-free life expectancy.”

For more details, including how to calculate whether you are low risk in each of the 5 lifestyle categories, 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.

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