A randomized, double-blind, placebo-controlled study published in the journal Nutrients, assessed the effects of omega-3 fish oil supplementation in patients with T2DM, finding that omega-3 polyunsaturated fatty acids (PUFAs) may influence the structure and function of gut bacteria.
The authors from Nanjing, China, said the results “may have significant implications for gut health and systemic inflammation, both of which are pivotal in the management of diabetes”.
How might omega-3 lower type 2 diabetes risk?
T2DM affects over 90% of people with diabetes worldwide, with a projected prevalence of 12.2% (783.2 million people) by 2045.
PUFAs—including α-linolenic acid, EPA and DHA—are known to benefit multiple health areas, and studies have shown that omega-3 PUFAs may help prevent T2DM by improving insulin signaling, reducing inflammation and influencing glucose metabolism.
Research also indicates that omega-3 PUFAs can positively impact gut microbiota, which helps restore a balanced microbiome and increase anti-inflammatory compounds like short-chain fatty acids.
Imbalances in the gut microbiome are linked to T2DM risk due to disrupted biochemical processes that lead to insulin resistance. Therefore, the researchers propose that a healthy gut microbiome can support metabolic and immune function, improving insulin sensitivity and blood glucose regulation.
Dysfunctional lipid metabolism can also play a role in T2DM, and studies have linked specific lipids, such as lysophospholipids, triacylglycerols and toxic 1-deoxyceramides with diabetes progression.
Omega-3 PUFAs can alter the diversity and abundance of gut microbiota. One study found that perilla oil rich in linolenic acid improved gut health in diabetic mice, and another dietary survey found a significant association between the level of total omega-3 PUFAs and the alpha diversity of the gut microbiome.
Fish oil supplementation for type 2 diabetes
In the three-month study, the Chinese researchers administered either a daily fish oil capsule or a placebo to two groups of 55 patients with T2DM.
Blood and fecal samples were collected at the beginning and end of the study to analyze serum lipids, glycemic parameters, gut microbiota diversity and lipidomics.
Findings indicated that fish oil-derived omega-3 PUFAs did not significantly reduce fasting plasma glucose levels compared to baseline. However, the fish oil group experienced significant reductions in serum fasting blood glucose, glycosylated hemoglobin, HOMA-IR, total cholesterol, triglycerides, LDL cholesterol and non-HDL levels compared to the placebo group after three months.
The intervention also altered glycerophospholipid metabolism and gut microbiota composition. Specifically, the fish oil group showed a significantly lower abundance of Desulfobacterota and reduced levels of Colidextribacter, Ralstonia and Klebsiella compared to the placebo group.
At the same time, levels of Limosilactobacillus, Lactobacillus and Haemophilus significantly increased. Relevant glycolipid metabolism indicators showed significant correlations with changes in serum lipid metabolites and intestinal bacterial and fungal profiles.
“Patients with type 2 diabetes may benefit from fish oil supplementation,” the researchers concluded, adding that "additional validation through large-scale population trials is imperative”.
Source: Nutrients 2024, 16(21), 3755
doi: 10.3390/nu16213755
“Improvement in Glycolipid Metabolism Parameters After Supplementing Fish Oil-Derived Omega-3 Fatty Acids Is Associated with Gut Microbiota and Lipid Metabolites in Type 2 Diabetes Mellitus.”
Authors: Xia, J. et al.