ASCEND: omega-3 supplements in people with diabetes

What does the research say?

In a large UK trial of adults with diabetes but no heart disease, a standard 1 g daily omega-3 supplement did not reduce heart attacks or strokes compared with an olive oil placebo.

The science

Participants were randomised to 1 g a day of omega-3 fatty acids (EPA and DHA) or olive oil capsules and followed for over seven years.

Serious vascular events occurred in 8.9% of the omega-3 group and 9.2% of the placebo group, which was not a significant difference. There was a small reduction in vascular deaths, but as a secondary finding it needs confirming.

Key findings

• No significant reduction in serious vascular events with 1 g/day omega-3.
• A possible small reduction in vascular deaths (secondary outcome).
• No safety concerns at this dose.

Limitations

• Tested a low-dose supplement, not oily fish.
• Only people with diabetes and no known heart disease were included.
• Olive oil as a placebo may itself have small effects.

References

1. ASCEND Study Collaborative Group; Bowman L, Mafham M, et al. Effects of n−3 fatty acid supplements in diabetes mellitus. N Engl J Med. 2018;379(16):1540–1550. doi.org/10.1056/NEJMoa1804989