Fitness Club

A new study of the cardiovascular benefit from using omega-3 enriched margarine in patients who previously suffered heart attacks turned up disappointing results, but its design may have been flawed.

The study, conducted over a period of 3 1/2 years by researchers in the Netherlands, concluded that the rate of cardiovascular problems, including resulting deaths, was substantially the same, whether the participants were consuming additional low doses of omega-3 fatty acids in their diet or not.

The 4,800 participants were mostly men, aged 60 to 80. All were taking medications during the study period to regulate blood pressure and cholesterol levels, as well as guard against clotting.

Daan Kromhout of the division of human nutrition at Wageningen University presented the findings Sunday at the European Society of Cardiology Congress in Stockholm.

Although at face value the study may seem to suggest that omega-3 supplementation provides no heart-health advantage, that conclusion might not be warranted, for several reasons. The amount of supplementation provided may have been too little. The patients consumed an average of 18.8 grams of margarine per day, which gave them an average of 226 milligrams of eicosapentaenoic acid (EPA) combined with 150 milligrams of docosahexaenoic acid (DHA), both derived from fish; and/or 1.9 grams of alpha-linolenic acid (ALA), found in plants. These amounts are considered "low dose." Heart patients are often advised to take 1,000 milligrams of omega-3 daily.The supplementation may have been provided too late for most of the study participants. Several years had intervened between the time many of them experienced their heart attacks and the beginning of the study. However, it is the period immediately following a cardiac event when a patient is most vulnerable.Some of the patients did seem to benefit from the supplementation. There was a "borderline significant reduction" in major heart events among women who consumed ALA, as well as among diabetics in the study. The supplementation appeared to protect against ventricular arrhythmia-related events, the researchers said. Unlike taking an omega-3 supplement in pill form, the study required patients to consume margarine, so a secondary food was required -- and that typically was bread. The study did not account for the possible negative effects of weight gain or increased blood pressure from eating extra bread, critics have noted. The strength of the patients' heart-protective medications may have overshadowed any potential benefit from the low-dose supplementation.The study was conducted among a population that typically consumes a lot of fish, which naturally provides omega-3. Supplementation might be of greater benefit to people who eat more meat and less fish (typical in the US).The study was not designed to consider the potential heart benefits of omega-3 supplementation among a general population of individuals who had never had a heart attack or other serious cardiovascular problems.

It's likely that more research is warranted to provide a clearer picture of the relationship between supplementation with omega-3 fatty acids and heart health.