Background: Fish oil (FO) supplements contain omega-3 fatty acids (ω-3 FAs), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), the two major components to which health benefits of FO are generally attributed.  FO supplements enriched with ω-3 FAs are prescribed to metabolic syndrome patients with severe hypertriglyceridemia to decrease their triglyceride levels. In contrary to FO’s beneficial effect on lipid metabolism, increased FO consumption is associated with an increased risk of Type 2 Diabetes (T2D). We have recently discovered that 3-carboxy-4-methyl-5-propyl-2-furanopropanoic acid (CMPF), a furan fatty acid (FuFA) metabolite, was found to be the major metabolite produced from FO consumption in humans. CMPF along with EPA and DHA are elevated in the serum of Gestational Diabetes Mellitus (GDM) patients. Elevated CMPF levels can cause beta cell dysfunction shown as impaired glucose stimulated insulin secretion (GSIS) in mice. Therefore, whether the effects of EPA and DHA at levels seen in GDM could impair glucose homeostasis and lead to the transition of GDM to T2D is yet to be determined.
Aim: The objective of this study is to determine the effects of EPA and DHA on glucose metabolism.
Method: Islets isolated from mice were treated with EPA and DHA at low and high doses for 24 hours. GSIS was then performed to determine the effects of EPA and DHA on beta cell function.  Animal models will be used to test the effect of EPA and DHA on glucose homeostasis in vivo.  Glucose tolerance test will be performed and ex-vivo GSIS will be used to determine the long-term effects of EPA and DHA on beta cell function.
Results: In vitro, mouse islets treated with EPA and DHA at lower concentrations had no difference on GSIS. In comparison, higher concentrations of EPA and DHA showed impaired GSIS indicating a dose dependent effect of FO on pancreatic beta cell function.
Discussion: The preliminary results indicate an effect of increased levels of EPA and DHA on pancreatic beta cell function that is similar to the effects seen of CMPF.  Upon conclusion, this study will provide a new prospective on our current understanding of the effects of fish oil supplements on glucose metabolism.

Identifying putative novel bioactive molecules in fish oil supplements