The Mediterranean Diet For Heart Health

Written by Dr. Steve Chaney on . Posted in Mediterranean diet

Can You Cut Your Heart Disease Risk In Half?

Author: Dr. Stephen Chaney

 

what ifShould you use the Mediterranean diet for heart health?

What if…

  • You could reduce your risk of heart disease by almost 50%…and…
  • It didn’t cost you an extra penny?
  • You didn’t need to lose weight (although you would probably get even better results if you did)?
  • You didn’t need to buy a gym membership and start a workout program (although you would probably get even better results if you did)?
  • There were absolutely no side effects?
  • There were considerable side benefits like reduced risk of type 2 diabetes, high blood pressure, inflammation, and cognitive decline as you aged?

Would you be interested? I’m willing to bet if this were a TV ad, you would be on the edge of your seat. If it were a new “magic” supplement, you might be reaching for your credit card before the ad was over. If it was the latest “miracle” workout machine, you might order it right away.

However, I am not talking about a magic pill or a miracle workout machine. I’m talking about a way of eating called the Mediterranean diet. Recent headlines have claimed that the Mediterranean diet can cut heart disease risk almost in half. This would lead you to believe you could use the Mediterranean diet for heart health.  Let’s look at the evidence behind that claim.

 

How Was The Study Designed?

omega-3 lowers heart disease riskThe study behind the headlines (C-M. Kastorini et al. Atherosclerosis, 246: 87-93, 2016) enrolled 2583 adults, ages 18-89, from the region around Athens, Greece in a 10-year study beginning in 2001-2002.

At the beginning of the study and at the 5 and 10-year mark, participants completed in-depth surveys about their medical records, lifestyle, and dietary habits. These surveys were conducted by trained personnel (cardiologists, general practitioners, dietitians, and nurses). Participants with active cardiovascular disease in the first survey were excluded from the study.

The study evaluated 4 things:

  • Cardiovascular disease risk factors including obesity, high cholesterol, high triglycerides, high blood pressure, diabetes, and inflammation.
  • Adherence to the Mediterranean diet (see below).
  • Heart disease incidence based on heart attacks, stroke, angina, ischemia, cardiac arrhythmias and deaths due to heart disease.
  • Confounding variables such as age, sex, family history of heart disease, smoking, and lack of physical activity. All comparisons were corrected for these confounding variables so that they did not influence the results.

Adherence to the Mediterranean diet was based on a diet analysis scoring system called MedDietScore. The Mediterranean diet is one which emphasizes fresh fruits and vegetables, whole grains, beans, nuts, fish, olive oil, and moderate consumption of red wine.  You can see this might lead you to believe in the Mediterranean diet for heart health.

The MedDietScore gives positive points based on how often these foods are consumed. It gives negative points based on how often meats, meat products, poultry, and full-fat dairy products are consumed. For alcohol, modest consumption is considered a positive, with either no or excess alcohol consumption rating a score of 0. The composite score ranges from 0 to 55, with higher values indicating greater adherence to the Mediterranean diet.

As an aside, you might think that everyone in Greece consumes a Mediterranean diet. Unfortunately, our unhealthy Western diet and our fast foods restaurants are making inroads in the birthplace of the Mediterranean diet.

 

The Mediterranean Diet for Heart Health?

Mediterranean diet for heart healthEven after correcting for confounding variables, the study results were impressive.

  • Each 10% increase in adherence to the Mediterranean diet was associated with a 15% decreased risk of developing heart disease during the 10-year study period.
  • When they compared participants in the upper third for adherence to the Mediterranean diet to those in the lower third, their risk of developing heart disease was decreased by 47%. That’s huge.

However, the results were even more impressive when they looked at the effects of the Mediterranean diet on other risk factors for heart disease.

  • For individuals with low adherence to the Mediterranean diet, each of those risk factors (obesity, high cholesterol, high triglycerides, high blood pressure, diabetes, and inflammation) independently increased the risk of developing heart disease. These results are identical to almost every other published study looking at those risk factors.
  • However, for individuals with high adherence to the Mediterranean diet, those same risk factors had only small, non-significant effects on the risk of developing heart disease. If this finding is verified by future studies, it would suggest that adherence to a Mediterranean diet has the potential to override risk factors like obesity, diabetes, high blood pressure and elevated cholesterol.

Of course, I would not recommend that you ignore obesity and other cardiovascular risk factors and just focus on following a Mediterranean diet. I’m pretty sure you will get even better results if you get your weight, blood sugar, cholesterol, and blood pressure under control in addition to following a Mediterranean diet. Who knows, you might even reduce your risk of heart disease by 75% or more.  So, should we believe in the Mediterranean diet for heart health?

What Does This Mean For You?

If this were the only published study showing that adherence to the Mediterranean diet reduces heart disease risk I would consider it speculative. However, it is only one of several recent studies that have come to a similar conclusion. At this point in time, the evidence is strong that following a Mediterranean-type diet will reduce your heart disease risk.  The Mediterranean diet for heart health seems to be true.

That brings me back to my opening statement. Following a Mediterranean diet:

  • Won’t cost you a penny. You are just spending your food budget on healthier foods.
  • May reduce your risk of heart disease by up to 47% even if you don’t lose weight, but I recommend that you do lose weight.
  • May be as effective as exercise at reducing your heart disease risk. That statement comes from a talk given by one of the authors when he was describing the study.
  • Has no side effects. You could probably achieve a 47% reduction in heart disease using a cardiologist-approved cocktail of 3-5 drugs, but those drugs would come with significant side effects and a considerable cost for someone.
  • Will likely come with side benefits like reduced risk of type 2 diabetes, high blood pressure, inflammation, and cognitive decline.

My question to you is: Now that you know that a simple dietary change could have all those benefits and no downside, are you willing to give it a try? If so, your heart may just thank you for it.

However, I don’t mean to imply that the Mediterranean diet is the only way to reduce your heart disease risk. If your blood pressure is elevated, you might want to try the DASH diet . If you want to reduce heart disease risk and also minimize cognitive decline as you age, you might want to consider the MIND diet .

Those three diets are actually quite similar. They all emphasize fruits, vegetables, whole grains, nuts, seeds, fish, and moderate amounts of healthy fats. They all minimize refined flour, pastries, sweets, red & processed meats. You won’t find a Twinkie or a Big Mac in any of them.

The Mediterranean diet for heart health?  Sure!

The Bottom Line

 

  • A recent study suggests that adherence to a Mediterranean type diet could reduce the risk of developing heart disease by up to 47%.
  • The beneficial effect of the Mediterranean diet was so strong that it overcame other cardiovascular risk factors such as obesity, high cholesterol, high triglycerides, high blood pressure, diabetes, and inflammation.
  • This study is likely to be accurate because it is fully consistent with several other studies looking at the effect of the Mediterranean diet on heart disease risk.
  • To put it into perspective, this simple dietary change.
    • Won’t cost you a penny. You just redirect your food budget.
    • Has zero side effects. You could probably achieve a similar 47% reduction in heart disease risk with a cardiologist-approved cocktail of 3-5 drugs, but that would come with multiple side effects.
    • Has side benefits such as reduced risk of type 2 diabetes, high blood pressure, inflammation, and cognitive decline
  • However, the Mediterranean diet is not the only game in town. Other studies suggest that the DASH diet and MIND diet are also effective at reducing heart disease risk.
  • Those three diet patterns (Mediterranean, DASH & MIND) are actually quite similar. They all emphasize fruits, vegetables, whole grains, nuts, seeds, fish, and moderate amounts of healthy fats. They all minimize refined flour, pastries, sweets, red & processed meats. You won’t find a Twinkie or a Big Mac in any of them.
  • Finally, I am not suggesting that you go on the one of these diets and just throw away your heart medicines without talking to your doctor. However, I would recommend that you talk with your doctor about implementing what the National Institutes of Health calls Therapeutic Lifestyle Change. All three dietary patterns are fully consistent with the NIH-recommended Therapeutic Lifestyle Change. The NIH recommends that Therapeutic Lifestyle Change be tried before considering cholesterol lowering drugs or be used along with cholesterol lowering drugs so that drug dosage can be minimized.

 

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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Comments (2)

  • Louise Levesque

    |

    Thank you for your article on the Mediterranean Diet. I suffer from high blood pressure and high cholesterol, so I am a prime candidate for heart disease. These three diets will help me avoid heart disease. Is there anything I can change in my diet to avoid strokes?

    Reply

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Is Our Microbiome Affected By Exercise?

Posted November 6, 2018 by Dr. Steve Chaney

Microbiome Mysteries

Author: Dr. Stephen Chaney

is our microbiome affected by exerciseIn a recent post,  What is Your Microbiome and Why is it Important,  of “Health Tips From The Professor” I outlined how our microbiome, especially the bacteria that reside in our intestine, influences our health. That influence can be either good or bad depending on which species of bacteria populate our gut. I also discussed how the species of bacteria that populate our gut are influenced by what we eat and, in turn, influence how the foods we eat are metabolized.

I shared that there is an association between obesity and the species of bacteria that inhabit our gut. At present, this is a “chicken and egg” conundrum. We don’t know whether obesity influences the species of bacteria that inhabit our gut, or whether certain species of gut bacteria cause us to become obese.

Previous studies have shown that there is also an association between exercise and the species of bacteria that inhabit our gut. In particular, exercise is associated with an increase in bacteria that metabolize fiber in our diets to short chain fatty acids such as butyrate. That is potentially important because butyrate is a primary food source for intestinal mucosal cells (the cells that line the intestine). Butyrate helps those cells maintain the integrity of the gut barrier (which helps prevent things like leaky gut syndrome). It also has an anti-inflammatory effect on the immune cells that reside in the gut.

However, associations don’t prove cause and effect. We don’t know whether the differences in gut bacteria were caused by differences in diet or leanness in populations who exercised regularly and those who did not. This is what the present study (JM Allen et al, Medicine & Science In Sports & Exercise, 50: 747-757, 2018 ) was designed to clarify.  Is our microbiome affected by exercise?

 

How Was The Study Designed?

is our microbiome affected by exercise studyThis study was performed at the University of Illinois. Thirty-two previously sedentary subjects (average age = 28) were recruited for the study. Twenty of them were women and 12 were men. Prior to starting the study, the participants filled out a 7-day dietary record. They were asked to follow the same diet throughout the 12-week study. In addition, a dietitian designed a 3-day food menu based on their 7-day recall for the participants to follow prior to each fecal collection to determine species of gut bacteria.

The study included a two-week baseline when their baseline gut bacteria population was measured, and participants were tested for fitness. This was followed by a 6-week exercise intervention consisting of three supervised 30 to 60-minute moderate to vigorous exercise sessions per week. The exercise was adapted to the participant’s initial fitness level, and both the intensity and duration of exercise increased over the 6-week exercise intervention. Following the exercise intervention, all participants were instructed to maintain their diet and refrain from exercise for another 6 weeks. This was referred to as the “washout period.”

VO2max (a measure of fitness) was determined at baseline and at the end of the exercise intervention. Stool samples for determination of gut bacteria and concentrations of short-chain fatty acids were taken at baseline, at the end of the exercise intervention, and again after the washout period.

In short, this study divided participants into lean and obese categories and held diet constant. The only variable was the exercise component.

 

Is Our Microbiome Affected By Exercise?

is our microbiome affected by exercise fitnessThe results of the study were as follows:

  • Fitness, as assessed by VO2max, increased for all the participants, and the increase in fitness was comparable for both lean and obese subjects.
  • Exercise induced a change in the population of gut bacteria, and the change was comparable in lean and obese subjects.
  • Exercise increased fecal concentrations of butyrate and other short-chain fatty acids in the lean subjects, but not in obese subjects.
  • The exercise-induced changes in gut bacteria and short-chain fatty acid production were largely reversed once exercise training ceased.

The authors concluded: “These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent of diet, and contingent on the sustainment of exercise.” [Note: To be clear, the exercise-induced changes in both gut bacteria and short-chain fatty acid production were independent of diet and contingent on the sustainment of exercise. However, only the production of short-chain fatty acids was dependent on obesity status.]

 

What Does This Study Mean For You?

is our microbiome affected by exercise gut bacteriaThere are two important take home lessons from this study.

  • With respect to our gut bacteria, I have consistently told you that microbiome research is an emerging science. This is a small study, so you should regard it as the beginning of our understanding of the effect of exercise on our microbiome rather than conclusive by itself. It is consistent with previous studies showing an association between exercise and a potentially beneficial shift in the population of gut bacteria.

The strength of the study is that it shows that exercise-induced changes in beneficial gut bacteria are probably independent of diet. However, it is the first study to look at the interaction between obesity, exercise and gut bacteria, so I would interpret those results with caution until they have been replicated in subsequent studies.

  • With respect to exercise, this may be yet another reason to add regular physical activity to your healthy lifestyle program. We already know that exercise is important for cardiovascular health. We also know that exercise increases lean muscle mass which increases metabolic rate and helps prevent obesity. There is also excellent evidence that exercise improves mood and helps prevent cognitive decline as we age.

Exercise is also associated with decreased risk of colon cancer and irritable bowel disease. This effect of exercise has not received much attention because the mechanism of this effect is unclear. This study shows that exercise increases the fecal concentrations of butyrate and other short-chain fatty acids. Perhaps, this provides the mechanism for the interaction between exercise and intestinal health.

 

The Bottom Line

A recent study has reported that:

  • Exercise induces a change in the population of gut bacteria, and the change was comparable in lean and obese subjects.
  • Exercise causes an increase in the number of gut bacteria that produce butyrate and other short-chain fatty acids that are beneficial for gut health.
  • These effects are independent of diet, but do not appear to be independent of obesity because they were seen in lean subjects but not in obese subjects.
  • The exercise-induced changes in gut bacteria and short-chain fatty acid production are largely reversed once exercise training ceases.

The authors concluded: “These findings suggest that exercise training induces compositional and functional changes in the human gut microbiota that are dependent on obesity status, independent on diet, and contingent on the sustainment of exercise.”

For more details and my interpretation of the data, 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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