Trials and studies by previous researchers have shown that dietary supplements of certain fatty acids of marine and plant origin protect the body against heart diseases. Researchers in the Netherlands examined whether such protection is offered in older patients with a history of heart attacks. It was found that low-dose supplementation with these fatty acids does not prevent occurrence of key heart-related conditions in such individuals. The researchers found that a small amount of EPA-DHA had no impact on the rate of major cardiovascular events in people who previously had a heart attack.
Different research studies have shown that n-3 fatty acids in one’s diet protect against cardiovascular diseases. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are n-3 fatty acids of marine origin, while alpha-linolenic acid (ALA) is plant-derived. Both types are reported to offer protection from diseases of the heart and the blood vessels. A previous study reported that the marine fatty acids reduced the rate of death from coronary heart disease by 20%, while another study reported a 36% drop. This study investigated whether these dietary elements offer protection in older people who have a history of heart attacks and who are on specific drugs.
- From 32 hospitals in the Netherlands, a total of 4,837 men and women between 60 and 80 years of age were recruited. All the study subjects, of which 78% were men, had suffered heart attacks before the beginning of the study and were on specific heart drugs.
- Every participant was randomly asked to consume as a dietary supplement, one of the following four different kinds of margarines: 1) without any n-3 fatty acids, 2) with marine fatty acids, 3) with plant-derived fatty acids and 4) with both kinds of fatty acids. Participants did not know the type of margarine they were consuming. They used these margarines daily for 40 months.
- The level of cholesterol and fatty acids in the blood, heart rate and blood pressure of the participants were recorded periodically.
- The study was terminated when each individual developed a heart condition requiring intervention.
- Of the 4,837 participants, 671 (13.9%) had a major heart-related incident causing termination of the study.
- There was not much difference with respect to the number of cardiovascular incidents between the subgroups, based on the type of margarine consumed.
- However, ALA supplementation showed a slight reduction (9%) in the number of major heart-related incidents in general and a more significant reduction (27%) in the sub-group of women.
The findings of this study are in contrast to previous research which showed that addition of the n-3 fatty acids to diets provided protection against heart disease. One reason for this could be that young populations were investigated in past studies while this study recruited older people who had had heart attacks. The participants were also receiving advanced drugs for treatment of their heart conditions, which may have had a protective effect, thus reducing the protective effects, if any, of the n-3 fatty acids.
Development of atherosclerotic plaque in blood vessels produces blockage and interference in blood circulation, causing high blood pressure, coronary artery narrowing and heart attacks. N-3 fatty acids prevent formation of hard atheromatous plaques. They also prevent occurrence of irregular heartbeats. Therefore, these fatty acids are labeled as protective agents for the heart. However, according to this study, “low dose supplementation with EPA-DHA or ALA did not significantly reduce the rate of major cardiovascular events among patients who had had a [heart attack] and who were receiving state-of-the-art…therapy.” Regarding ALA and women specifically, it was noted that there were not as many heart-related incidents among women who received ALA compared to women who took a placebo.
For More Information:
N-3 Fatty Acids and Cardiovascular Events after Heart Attack
The New England Journal of Medicine, August 2010
By Daan Kromhout, PhD; Erik J. Giltay, PhD
From the Wageningen University, Wageningen, the Netherlands, and Leiden University Medical Center, Leiden, the Netherlands