CME Author: Charles P. Vega, MD
Released: 08/19/2010; Valid for credit through 08/19/2011
August 19, 2010 — Data from more than 84 000 women over 26 years suggest that shifting dietary protein sources away from red meat to more poultry, fish, and nuts can reduce an individual's risk of coronary heart disease [1].
Dr Adam Bernstein (Brigham and Women's Hospital, Boston, MA) and colleagues analyzed data from 26 years of follow-up from 84 136 women, aged 30 to 55 years, in the Nurses' Health Study. Their results are published online August 16, 2010 in Circulation. The patients enrolled in the study had no known cancer, diabetes mellitus, angina, myocardial infarction, stroke, or other cardiovascular disease. Their diet was tracked with a standard questionnaire every 4 years. During 26 years of follow-up, 2210 incident nonfatal infarctions and 952 deaths from coronary heart disease were reported.
A multivariable analysis of diet and traditional risk factors, like age and smoking, shows that consumption of red meat and high-fat dairy were significantly associated with an elevated risk of coronary heart disease, whereas higher intakes of poultry, fish, and nuts were significantly associated with lower risk.
A statistical model controlling for total intake of calories, cereal fiber, alcohol, trans-unsaturated fatty acids, and other potential nondietary confounding variables, shows that one serving per day of nuts was associated with a 30% lower risk of coronary disease than one serving per day of red meat. The same one-serving exchange comparison found a 13% lower risk with low-fat dairy, a 19% lower risk with poultry, and a 24% lower risk with fish.
The latest analysis from the Nurses' Health Study affirms the findings from 14 years and 16 years of follow-up, and red meat continues to be significantly related to coronary disease risk, independent of measured confounders and known intermediate outcomes.
The authors also found a link between total meat intake and coronary disease risk, likely driven by the high proportion of red meat in the total meat intake, but the strong association between red meat and coronary disease cannot be entirely explained by the intake of processed meat, because red meat remained associated with coronary disease even when processed meat was excluded. However, a recent study by Dr Renata Micha (Harvard School of Public Health, Boston) found that eating unprocessed red meat did not increase the risk of coronary heart disease or diabetes, but eating 50 g of processed meat per day was associated with a 42% higher risk of CHD and a 19% increased risk of diabetes, most likely because of the volume of sodium and other preservatives.
The authors recall that dietary iron--particularly the heme iron found in red meat--has been positively associated with myocardial infarction and fatal coronary disease in most, but not all, previous studies. The effect of heme iron on systolic blood pressure, the high sodium content of processed meats, and the compounds created by cooking red meat, such as heterocyclic amines and advanced glycation end-products, might also increase coronary risk.
Bernstein et al cite a recent meta-analysis by Dr Dariush Mozaffarian (Harvard University, Boston) and colleagues, showing that reducing saturated fat did not reduce coronary risk, but replacing saturated fats with polyunsaturated fats significantly reduced the risk of coronary heart disease.
"When major sources of protein, such as nuts and fish, are used to replace red meat, saturated fat, heme iron, and sodium decrease, whereas intake of polyunsaturated fat increases. The benefit on CHD risk of such a substitution is thus likely to be due to multiple simultaneous changes in nutrient intake," Bernstein et al conclude.
References
1. Bernstein A, Sun Q, Hu F, et al. Major dietary protein sources and risk of coronary heart disease in women. Circulation 2010; DOI:10.1161/circulationaha.109.915165. Available at http://circ.ahajournals.org/.
source : http://cme.medscape.com/viewarticle/727146?src=cmemp&uac=97984HK
regards, taniafdi ^_^
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