Adiponectin is a hormone, which has numerous beneficial effects on metabolic process such as glucose regulation and inflammation. Long-term studies conducted in humans have shown that higher levels of adiponectin are associated with lower risks of type 2 diabetes.
The meta-analysis reviewed and analyzed results from 14 randomized, placebo-controlled clinical trials. In total, 682 subjects were treated with fish oil, and 641 were given placebos – most commonly olive and sunflower oils. In those taking fish oil adiponectin levels increased by 0.37 ug/mL. The results also suggested the effect of fish oil on adiponectin differed substantially across the trials, suggesting that fish oil supplementation may have stronger influence on adiponectin in some populations and weaker effects in others.
Investigators working on the present study scoured multiple databases throughout June of 2012 to identify randomized controlled trials (RCTs) using fish oil supplementation or isocaloric fishmeal feeding that evaluated adiponectin as an outcome. Of the 110 studies found, only 14 RCTs met the inclusion criteria. In total, 682 subjects were treated with fish oil, whereas, 641 subjects were given placebo.
Effect estimates were pooled using inverse-variance weighted, random effects meta-analysis. Results revealed that fish oil increased adiponectin by 0.37 mcg/mL.
According to one of the researchers, Jason Wu, it is still unclear whether fish oil influences glucose metabolism and development of type 2 diabetes. However, Wu states, "Results from our study suggest that higher intake of fish oil may moderately increase blood levels of adiponectin, and these results support potential benefits of fish oil consumption on glucose control and fat cell metabolism."
Effect of Fish Oil on Circulating Adiponectin:The Endocrine Society’s Journal of Clinical Endocrinology & Metabolism (JCEM).