Omega-3 fact check: Helpful or hopeless?

In a recent study, researchers found that omega-3 fatty acids don’t prevent cardiovascular events, but authors of another study published at the same time concluded that omega-3s do reduce cardiovascular risk. So, do omega-3s work for the heart or don’t they?

Meanwhile, other researchers recently published findings—some positive, some negative—about omega-3s for longevity, dry eye, anxiety, and even premature birth. It’s hard to keep track of it all. Here’s an update on some of the latest research to help sort out the confusion.

Cardiovascular disease

Observational studies have linked higher intake of omega-3 fatty acids with lower risks for cardiovascular disease, but large clinical trials on the matter are sparse. So, in the randomized, double-blind, placebo-controlled Vitamin D and Omega-3 Trial (VITAL), researchers studied whether omega-3 fatty acids could prevent cardiovascular events.

The VITAL trial investigated a daily dose of omega-3s (1-g fish-oil capsule containing 840 mg of omega-3 fatty acids: 460-mg eicosapentaenoic acid [EPA] and 380-mg docosahexaenoic acid [DHA]) among 25,871 older adults. After an average follow-up of about 5 years, the researchers concluded that people who took omega-3s didn’t have a significantly lower incidence of major cardiovascular events (heart attack, stroke, or death from cardiovascular causes) compared with people taking placebo.

However, in the same issue of TheNew England Journal of Medicine, different researchers reported the results of another study of more than 8,000 adults, the Reduction of Cardiovascular Events with Icosapent Ethyl-Intervention Trial(REDUCE-IT), in which participants who took an omega-3 supplement had a 25% reduced risk of major ischemic events—including cardiovascular death, heart attack, stroke, coronary revascularization, and unstable angina.

But there were two big differences between the trials. The first was the cohort of participants. Participants in the VITAL trial represented the general population, while the REDUCE-IT trial included only patients with cardiovascular disease who had high triglyceride levels and were already taking statins.

The second big difference between the trials was the type and dose of omega-3 fatty acids. The VITAL trial used a combination EPA/DHA omega-3 supplement (available as Lovaza^® and as a generic), which is the dose recommended by the American Heart Association for cardioprotection. The REDUCE-IT trial used a supplement consisting of only EPA omega-3 fatty acid in ethyl-ester form (available as Vascepa^®) dosed 2 g twice daily.

So, whether omega-3s help heart health may depend on both the pill and the patient.

Longevity

In a study involving 2,622 older adults (mean age, 74.4 years) from the Cardiovascular Health Study cohort, researchers reported that a higher level of circulating omega-3 fatty acids from seafood was associated with a higher likelihood of healthy aging.

“We found that older adults who had higher levels of omega-3 from seafood were more likely to live longer and healthier lives,” according to lead study author Heidi Lai, PhD, Friedman School of Nutrition Science and Policy, Tufts University, Boston, MA.

Because this was an observational study, correlation doesn’t confer causation. Still, Dr. Lai and coauthors concluded that their findings support guidelines recommending that older adults increase their dietary consumption of omega-3 fatty acids through seafood. The investigators didn’t ask specifically about omega-3 supplements.

The VITAL trial was funded by the National Institutes of Health. The REDUCE-IT trial was funded by Amarin Pharma. Omega-3 research on the Cardiovascular Health Study cohort was supported by the National Heart, Lung, and Blood Institute.