Meta Analysis Finds Omega-3s May Not Lower Cardiac Risk, CRN Discounts Findings

The findings "do not justify the use of omega-3 as a structured intervention in everyday clinical practice or guidelines supporting dietary omega-3 polyunsaturated fatty acid administration," the researchers reported in the Sept. 12 issue of the Journal of the American Medical Association.

12 Sep 2012 --- Omega-3 polyunsaturated fatty acid supplementation does not appear to reduce the risk of cardiovascular or cerebrovascular events, a meta-analysis showed.

In pooled results from 20 randomized trials including more than 68,000 patients, supplementation did not reduce the risks of all-cause mortality, cardiac death, sudden death, myocardial infarction (MI), or stroke, according to Moses Elisaf, MD, PhD, of the University Hospital of Ioannina in Greece, and colleagues.

The findings "do not justify the use of omega-3 as a structured intervention in everyday clinical practice or guidelines supporting dietary omega-3 polyunsaturated fatty acid administration," the researchers reported in the Sept. 12 issue of the Journal of the American Medical Association.

"Randomized evidence will continue to accumulate in the field, yet an individual patient data meta-analysis would be more appropriate to refine possible associations related to, among others, dose, adherence, baseline intake, and cardiovascular disease risk group," they wrote.

In response to the meta-analysis, the Council for Responsible Nutrition (CRN), the leading trade association representing the dietary supplement industry, issued the following statement:
Statement by Duffy MacKay N.D., vice president, scientific and regulatory affairs, CRN: “Consumers should not discount the many proven benefits of omega-3 fatty acids in all stages of life.  There is extensive scientific evidence demonstrating the importance of omega-3 fats during pregnancy/lactation, breastfeeding and childhood.  Furthermore, omega-3 fats have a role in maintaining the health of adults as well as in the prevention of age-related chronic diseases (e.g., cardiovascular disease and cognitive decline). This study does not change the current recommendations by authoritative bodies such as the World Health Organization, American Heart Association and the U.S. National Academies of Science, who recommend adequate consumption of omega-3 fats.”

“Our main concern is that the results of this meta-analysis will be taken out of context.  The attraction of doing a meta-analysis is to combine comparable smaller clinical studies to assess whether similarities in the combined results exist. The problem is that this meta-analysis combined studies that were not comparable in their design (e.g., studies on healthy individuals were combined with those targeting diseased individuals), which makes the results more skew. Second, omega-3 fatty acids are vital nutrients and not drugs.  Many of the studies included in the meta-analysis were conducted on diseased individuals already undergoing treatment with one or more drugs (e.g., statins), which may mask the less potent and more long-term effects of omega-3 fats.  Along these lines, the researchers apparently did not examine within each individual study included in the meta-analysis whether individuals in the placebo group were sufficient or insufficient in their dietary intake omega-3 fats.  Without that information, they could not have controlled for this variable. In this regard, studies on drugs are far simpler than those of nutrients (the treatment group gets the drug and the placebo group does not); with nutrients, if participants in the control group already have a diet sufficient in that substance, then it will be that much harder to demonstrate any benefit among the treatment participants. It is impossible for five researchers to control the diet of almost 70,000 patients over several years (particularly as a retrospective meta-analysis), as omega-3 fats are widespread throughout a variety of foods.”

“In conclusion, consumers should not be swayed by these results. While people should be eating a diet high in fatty fish which contain these nutrients, the reality is that people are simply not doing this. Omega-3 supplements serve as an affordable, convenient and safe way to obtain omega-3 fatty acids and the array of health benefits they offer.”