Science Update

New Review Demonstrates the Effect of Fish Oil on Adiponectin and Leptin Levels

Insulin resistance is caused by an impairment of insulin’s actions on glucose, protein, and fat metabolism, which is associated with adipose tissue. Excessive visceral and subcutaneous fat causes adipocyte dysfunction, which leads to inflammation, and as a result, this causes a decrease in adiponectin levels and an increase in leptin levels.

Adiponectin is a protein hormone that mediates numerous metabolic processes, such as glucose regulation, insulin sensitivity, and inflammation mitigation. It has an inverse relationship with insulin resistance, dyslipidemia, obesity, and cardiovascular disease.

Typically, all immune cells contain leptin receptors indicating their role in the immune response. Leptin has been shown to facilitate the production of pro-inflammatory cytokines, which have been associated with chronic systemic inflammation in aging.

According to a new review published in Nutrition Research, the researchers investigated the effects of omega-3 fatty acids on adiponectin and leptin levels. This review consisted of 31 studies that involved 12 to 1,081 participants. Twenty-nine studies used parallel designs and the remaining studies used a crossover design with a 2 × 2 factorial design. Double blinding occurred in 53% of the studies. Five studies were single-blinded. Nine studies did not implement blinding. The research team included all studies on omega-3 fatty acid supplementation that reported leptin, adiponectin, or a leptin-to-adiponectin ratio.

As a result, 18 studies demonstrated higher adiponectin levels or lower leptin levels from omega-3 fatty acid supplementation with nine of the studies indicating statistically significant differences. Supplementation doses and duration varied among the studies. In nine studies, significantly higher adiponectin levels or lower leptin levels were reported with an omega-3 fatty acid dosage of 520 mg to 4.2 grams per day between 4 and 24 weeks in duration.

Essential fatty acids should be included in our diets and consumed for overall health, but most individuals with insulin resistance are deficient in them. Fish oils may help improve insulin sensitivity and support a normal inflammatory response. Other dietary supplements shown to be effective for affecting adiponectin and inflammation include tocotrienols, curcumin, and quercetin.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS

Source: Rausch J, Gillespie S, Orchard T, Tan A, McDaniel JC. Systematic review of marine-derived omega-3 fatty acid supplementation effects on leptin, adiponectin, and the leptin-to-adiponectin ratio. Nutr Res. 2020;85:135-152.