Thursday, September 9, 2010

Omega-3 Margarine No Better for Heart

Margarine enriched with low doses of Omega-3 fatty acids does not appear to decrease the recurrence of cardiac events for older heart attack survivors.

A new study published last week in the New England Journal of Medicine laid out the results of the Alpha-Omega randomized trials in the Netherlands. The study gathered almost 5,000 subjects, all heart attack survivors aged 60 to 80, divided in four groups, all of which were provided with margarine. Margarine for Group A was enriched with 400 mg of fish-oil based DHA and EPA ((1/2 the AMA recommended dose), Group B had 2,000 mg of ALA from soybean oil and walnuts, Group C had all three fatty acids, while Group D received placebo margarine only. Each group participant was supposed to lather his margarine portion daily on 3 to 4 slices of bread.

The outcome was disappointing. Dr. Daan Kromhout, of Wageningen University, one of the authors of the study, reported that none of the margarines had any effect on the rate of major cardiovascular events for the general population (although diabetic patients, much more vulnerable to heart attacks, should a 50% reduced risk of negative outcomes). This conclusion appears to go against the results of numerous previous studies. Dr. Alfred Bove, of Temple University was surprised by the findings "because most of the data on omega-3 fatty acids come from epidemiologic studies and those were positive."

Several possible explanations were being proposed. Dr. Kromhout suggested that one explanation may be that, because the patients already received excellent cardiovascular treatments (most patients taking daily medicines to control cholesterol and blood pressure), the enriched margarines may not have been able to improve their health any further. Dr. Scott Wright, MD, of the Mayo Clinic in Rochester, Minn., suggested that the enrichment vehicle might have been wrong, since margarine requires patients to eat more bread, meaning possible weight gain and additional sodium intake. Some commentators, such Dr. Gregg C. Fonarow, of UCLA, mentioned the possibility that the doses simply needed to be higher: "the dosing here may have been just too low." Finally, alluding to the fact that treatment is most important immediately after the occurrence of the first cardiac event, others, such as Dr. Stephen Kopecky, of the Mayo Clinic, suggested that patients were enrolled too late after their initial heart attack: "If you wait too long, sometimes you miss that window to benefit them."

Recently, hormone therapy for post menopausal women, generally recommended to reduce cardiovascular risk, was shown by a large randomized controlled trial to actually increase that risk. The obvious concern is that Omega-3 fatty acids, one of the most popular supplements, could be facing the same situation: their efficiency so far has been primarily suggested by epidemiologic studies (i.e. post facto analysis of data, rather than randomized control trials which are the only way to truly prove causality).

Want to read more about it? Try WebMD, Medpage, AP, US News, Time, Cardiovascular Business, Business Week, Money Times, Food Consumer, Economic Times, Healthy Living, ABC News, and PhysOrg.

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