Omega-3 supplements may not protect a patient from heart disease or vascular events, according to a meta-analysis published in JAMA Cardiology.
Consumption of omega-3 fatty acids found in fish has been reported to lower the risk of death from coronary heart disease (CHD) in observational studies, according to Theingi Aung, MBBS, and colleagues—but randomized trials of omega-3 supplements have produced varying results.
Aung et al. pulled data from 10 randomized studies containing 77,917 participants (61.4 percent men; average age 64 at baseline) lasting an average of 4.4 years.
Compared to control groups, individuals taking supplements had risk reductions of 7 percent for CHD death, 3 percent for nonfatal myocardial infarction and 4 percent for any CHD events. However, none of the associations reached statistical significance.
“The results provide no support for current recommendations to use omega-3 fatty acid supplements for the prevention of fatal coronary heart disease or any cardiovascular disease in people who have or (are) at high risk of developing cardiovascular disease,” the researchers wrote.
Aung and colleagues said it is unclear what caused the conflicting results in the individual trials. Different inclusion criteria for prior diseases, concomitant statin use and differing secondary prevention treatments are potential explanations, they wrote.
Professional societies also differ in their guidelines regarding omega-3 fatty acid supplements, the authors noted.
“The 2016 European Society of Cardiology and European Atherosclerosis Society guidelines for prevention of cardiovascular disease indicated that it is debatable whether omega-3 FAs may exert a protective effect, and the 2016 guidelines on the management of dyslipidemia indicated that more evidence on the efficacy of omega-3 FA supplements for prevention of clinical outcomes is needed to justify their prescription,” Aung and coauthors wrote. “In contrast, the American Heart Association recommended that the use of omega-3 FAs for prevention of CHD is probably justified in individuals with prior CHD and those with heart failure and reduced ejection fractions.”
The dosing of the supplements ranged from 226 to 1,800 milligrams per day in the meta-analysis. Ongoing trials are evaluating whether higher doses (3 to 4 grams/day) impact the risk of vascular events.