A review of previously published studies suggests that vegetable and nut intake and a Mediterranean dietary pattern appear to be associated with a lower risk for heart disease, according to a report published in the April 13 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. However, intake of trans-fatty acids and foods with a high glycemic index may be harmful to heart health.
"The relationship between dietary factors and coronary heart disease has been a major focus of health research for almost half a century," the authors write as background information in the article. Although "a wealth of literature" has been published on the topic, "the strength of the evidence supporting valid associations has not been evaluated systematically in a single investigation."
Andrew Mente, Ph.D., of the Population Health Research Institute, and colleagues conducted a systematic search for articles investigating dietary factors in relation to heart disease published between 1950 and June 2007. A total of 146 prospective cohort studies (looking back on the habits of a particular group of individuals) and 43 randomized controlled trials (where participants are randomly assigned to a dietary intervention or a control group) were identified and included in the systematic review.
The Mediterranean diet looks beneficial. No surprise there. Vegetables, nuts, and foods with low glycemic index are good for you.
When the researchers pooled the study results and applied a predefined algorithm, "we identified strong evidence of a causal relationship for protective factors, including intake of vegetables, nuts and monounsaturated fatty acids and Mediterranean, prudent and high-quality dietary patterns, and harmful factors, including intake of trans–fatty acids and foods with a high glycemic index or load and a western dietary pattern," they write. "Among these dietary exposures, however, only a Mediterranean dietary pattern has been studied in randomized controlled trials and significantly associated with coronary heart disease."
In addition, modest relationships were found supporting a causal relationship between intake of several other foods and vitamins and heart disease risk, including fish, omega-3 fatty acids from marine sources, folate, whole grains, alcohol, fruits, fiber and dietary vitamins E and C and beta carotene. Weak evidence also supported causal relationships between vitamin E and ascorbic acid supplements, saturated and polyunsaturated fatty acids and total fats, alpha-linoleic acid, meat, eggs and milk.
No one food shows a strong causal relationship. You have to get a lot of things right or a lot of things wrong to push you firmly toward lower or higher disease risk. Where to start? Find out what are the low and high glycemic index foods. I lowered my own average food glycemic index by changing rice brands (Uncle Ben's Converted is one of the more surefire ways to shift to lower glycemic index foods - and they ought to pay me to say that ;)) and eating more beans and vegetables.
|Share |||Randall Parker, 2009 April 13 11:05 PM Aging Diet Heart Studies|