Omega-3 supplements “should not be encouraged” for prevention or treatment of type 2 diabetes, with a review finding no convincing evidence that upping intake affects the risk of developing diabetes.

Researchers say previous studies have suggested omega-3, omega-6, and total polyunsaturated fatty acids may protect against type 2 diabetes, but the data has been inconclusive.

There have also been questions raised about the effect of the fatty acids on glucose metabolism.

“No convincing evidence suggests that altering intakes of long-chain omega-3, alpha-linolenic acid, omega-6 or total PUFA [polyunsaturated fatty acid] intakes alters glucose metabolism or risk of diabetes,” the University of East Anglia researchers wrote in the BMJ.