A recent clinical trial resulted in a significant reduction in serum triglycerides among people with type 2 diabetes who were given fish oil, which contains the omega-3 fatty acids EPA and DHA, compared with a corn oil placebo. Triglycerides are the main type of fat in the body and, when elevated, contribute to the development of cardiovascular disease.

At the end of the 12-week randomized, placebo-controlled trial, triglycerides decreased by an average of 21.39% in the fish oil group, while those who received the placebo experienced an insignificant reduction. Among the various types of circulating lipids that were studied, researchers observed an enrichment in the types that contained omega-3 PUFAs. “Our results suggest that fish oil intervention not only reduced blood triglyceride levels but also impacted the composition of the serum lipidome,” Jieli Lu of Shanghai Jiao Tong University School of Medicine and colleagues wrote.

When comparing the gut microbiomes (bacteria and other microbes that colonize the gastrointestinal system) of participants who received fish oil with those who received a placebo, fish oil had limited effects, yet microbiome composition at the beginning of the study was predictive of the change to triglyceride levels that occurred in response to fish oil.

The trial included 309 men and women with type 2 diabetes and high triglycerides. One hundred forty-seven participants were given 4 grams of fish oil, and a placebo group was assigned to 4 grams of corn oil for 12 weeks. The findings were published in the January 10, 2025, issue of the journal Med.¹

"Our study demonstrates the efficacy of omega-3 fatty acids in reducing triglyceride levels in Chinese patients with type 2 diabetes and high triglycerides," the authors concluded. "These findings have important implications for the development of personalized dietary interventions to effectively manage high triglycerides and related metabolic disorders."