An Apple a Day Keeps the Cardiologist Away

appleLast week I shared with you a study suggesting that eating more  fruits and vegetables makes you happy. One reason these people  may be happier may be that they are also healthier.  For example, today’s study (Crowe et al, Am. J. Clin. Nutr., doi: 10.3945/ajcn.112.044073) shows that vegetarians have a 32% lower risk of developing heart disease.

This is a very robust study involving 45,000 health conscious volunteers from England & Scotland. Although the study did not specifically set out to enroll vegetarians, it turned out that 34% of the participants in the study were vegetarian. That was fortuitous because it gave the study high statistical power.

At entry into the study the participants were asked to fill out a food-frequency questionnaire covering everything they ate over the past 12 months. If they ate any meat, fish, eggs or dairy products over the past 12 months they were classified as non-vegetarians. Simply put, the vegetarians were a pretty dedicated bunch.

The scientists running the study followed the participants for an average of 11.6 years and measured what they called “incident heart disease”, which is defined as both deaths from heart disease and hospital admissions for heart disease for symptoms ranging from angina to an actual non-fatal heart attack.

The results were impressive. The vegetarians had a 32% lower incidence of heart disease over the next 11 years than the non-vegetarians.

Similar results have been reported in previous studies, but it was never clear whether it was the vegetarian diet or other lifestyle factors (exercise, smoking and BMI, for example) that were responsible for the decreased heart attack risk. This study was large enough so that it was possible to control for all of those lifestyle factors.

When sex, age, smoking, exercise, use of birth control or hormone replacement therapy for menopause, and pre-existing heart disease risk factors were taking into account, the decreased risk of heart disease was unaffected. As a whole the vegetarians weighed less than the non-vegetarians, but even when BMI was taken into account, the vegetarians had a 28% lower incidence of heart disease.

The reasons for the decreased heart disease risk aren’t entirely clear. The vegetarians did have lower levels of non-HDL cholesterol and blood pressure, which probably accounted for most of the decreased risk, but factors like a higher ratio of polyunsaturated to saturated fat intake might also contributed.

So what is the bottom line for you and me?

1) This is this strongest evidence yet that a vegetarian diet is beneficial. So if you are considering going vegetarian, this might be the final bit of evidence that convinces you that it is worth the effort.

2) However, if you are like most Americans, a vegetarian diet is probably a lot different than the way you are currently eating. The most recent diet survey shows that if you exclude white potatoes, potato chips and French fries, most Americans average only one cup/day of vegetables. And if you exclude fruit juices and foods like fruit roll-ups, most Americans average only ∏ cup/day of fruit. That’s a far cry from a vegetarian diet!

3) And if you are mostly vegetarian like Suzanne and me, this study doesn’t provide much guidance. We’d like to think that a semi-vegetarian diet is beneficial and there are studies suggesting that reducing consumption of red and processed meats are beneficial, but those studies are not nearly as strong as this one.

So you might be asking whether this study was enough to convince me that I want to go completely vegetarian. My answer is “probably not”. I’m a great fan of that Woody Allen quote: “Vegetarians don’t live longer. It just seems that way.”

To Your Health!
Dr. Stephen G Chaney

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