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Omega-3 Supplementation Fails to Prevent Heart Disease

Oct 13, 2018
 

Author: Steve Freed, R.PH., CDE


Omega-3 supplementation fails to prevent heart disease in new study; no significant statistical differences found between patients with diabetes using supplement versus placebo.

Fish oil supplementation, namely omega-3 fatty acids, is recommended by The American Heart Association for prevention of coronary heart disease and overall cardiovascular health in the general population. Patients with diabetes are known to be at greater risk for heart disease than those without diabetes, and thus an interest in natural supplements to decrease this risk is often a topic of discussion.

In a new study published in The New England Journal of Medicine, investigators sought to examine the safety and efficacy of omega-3 fatty acid supplementation in patients with diabetes. Due to the lack of data regarding this specific topic, investigators of the present trial performed A Study of Cardiovascular Events in Diabetes (ASCEND) to assess the effects.

A total of 15,341 participants with diabetes but no evidence of cardiovascular disease upon trial entry were analyzed for results. Men and women ages 40 years and older were included in the study if they had a present diagnosis of diabetes without evidence of cardiovascular disease. Enrolled participants were randomly placed on a once-daily regimen of either 1g omega-3 fatty acid capsules or placebo containing olive oil. Every six months, each patient received a questionnaire regarding adherence, adverse events, and use of antiplatelet or anticoagulation therapy with a follow-up duration of 7.5 years.

The primary outcome for the trial was the first serious vascular event, defined as nonfatal myocardial infarction, stroke, transient ischemic attack, or vascular death. The secondary outcome was considered a composite of any serious vascular event or arterial revascularization procedure.

A total of 689 patients in the group who took omega 3’s and 712 patients in the group who took placebo experienced a serious vascular event, allowing investigators to conclude that no statistical significance was observed between the groups (p=0.55). There was also no significant difference observed in rates of death from all cause between groups. In regards to secondary outcomes, no significant difference was noted between groups for a composite of serious vascular events or revascularization.

Due to the increased risk of heart disease in patients with diabetes, prevention by any means is key in this patient population. Overall, this study showed that in patients with diabetes and no evidence of cardiovascular disease, omega-3 fatty acid supplementation failed to prevent heart disease compared to placebo. Additionally, supplementation with omega-3s also failed to prevent revascularization and death from any cause compared to placebo.

While numerous studies have shown that fish oil supplements are beneficial for preventing cardiovascular disease in the general population, it seems that the same cannot be said for those with diabetes. The verdict is still out on the best way to prevent heart disease in this specific patient population, but we can safely assume that supplementing a diet with fish oil will no better reduce the risk of CVD than a capsule of olive oil.

Practice Pearls:

  • In patients with diabetes and no history of cardiovascular disease, supplementation with omega-3 fatty acids failed to reduce the risk of cardiovascular disease compared to placebo.
  • Omega-3 fatty acid supplementation also failed to reduce the risk of revascularization and incidence of death in patients with diabetes and no CVD compared to placebo.
  • Omega-3 fatty acid supplementation should not be recommended in patients with diabetes for reduction of cardiovascular complications.

Reference:

Bowman, L. et al. (2018). Effects of n−3 Fatty Acid Supplements in Diabetes Mellitus. The New England Journal of Medicine. doi:10.1056/NEJMoa1804989