Heart-Healthy Diets Put To The Test

The summary by Jennifer Warner from WebMD Health News about the health merits of various dietsis is as succinct as one can be. It details the results of a review of diet and health disease studies by Andrew Mente, PhD, of the Population Health Research Institute and colleagues (published in the Archives of Internal Medicine):

The researchers analyzed 146 studies that looked back at the dietary habits of a particular group of individuals in relation to their risk of heart disease as well as 43 studies in which people were assigned to a diet or a comparison group to measure the effect on heart disease risk.

Researchers pooled the results of the studies and then rated the strength of evidence behind the various heart-healthy diet claims.

The final results showed only three specific dietary factors had strong evidence behind them as proven heart disease fighters:

  • Vegetable-rich diet
  • Eating nuts rich in monounsaturated fatty acids like walnuts and other nuts.
  • Following a Mediterranean-style diet high in vegetables, legumes, fruits, nuts, whole grains, cheese or yogurt, and fish

Of these, only a Mediterranean-style diet has been shown in randomized controlled studies to reduce the risk of heart disease.

meddiet2

Researchers also found strong evidence behind the negative effects of the following dietary factors on heart disease risk:

  • Following a Western-style diet high in processed meats, red meat, butter, refined grains, and high-fat dairy products
  • High-glycemic index foods
  • Trans-fatty acids

The evidence behind all other dietary factors was “too modest to be conclusive” according to researchers.

***

One should weigh the pros and cons of eating a ton of fish. Do the benefits of consuming the omega (3-6-9, whatever) fatty acids outweigh the costs to the environment? It depends on the origin of the fish, for sure. By some estimates, sea and ocean fish populations may be extinct within 50 years if our course of action remains unchanged.

Furthermore, women who are pregnant or may become pregnant (sounds like a warning label, no?) may wish to consider the possible effects of mercury consumption on their unborn children. Minamata disease is an extreme example of what can happen. Thankfully, most of us do not live by or eat from waters contaminated by the local factory’s toxic methyl mercury dumpings.

The advice to lay off the red and processed meats is further substantiated by another study.  This study tracked the eating habits of 545,563 men and women and found that Americans who ate the most red meat boosted their overall risk of death by 30% during a 10-year period compared to those who ate the least.  To be fair, eating a lot of red and processed meat was correlated with a host of other negative factors like smoking, being overweight, exercising less and eating fewer fruits and vegetables.  However, the researchers calculated that if the heavy meat-eaters reduced their intake (even with the other factors staying the same), they could prevent 11% of the deaths among men and 16% of the deaths among women.  This is a big difference considering the data on unaltered diets:

Men who were big meat eaters had a 22% increased risk of death from cancer and a 27% higher risk of cardiovascular disease compared with men who ate the least. For women, high red meat consumption raised the risk of death from cancer by 20% and the risk of heart disease by 50%, according to the study, to be published in Tuesday’s edition of Archives of Internal Medicine.

…The process of cooking (red) meat produces several carcinogenic compounds that could be contributing to the higher risk of death, the researchers said. In addition, the iron in red meat may cause oxidative damage, while the saturated fat has been linked to breast and colorectal cancer.

Tasty, eh?  Frightened meat-eaters may take comfort in the fact that eating white meat or fish did not lead to the same negative outcome.  Though, I’m not so sure about the “other white meat”…

Cartoon by Tom Toles

May 11, 2009  Tags: , ,   Posted in: Health, Science & Technology

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