Do omega-3s help prevent type 2 diabetes?
Type 2 Diabetes: Help from Omega-3 EPA and DHA?
High concentrations of Omega-3 in serum may protect against type 2 diabetes. In middle-aged men, high consumption of fish rich in polyunsaturated fatty acids, especially EPA (eicosapentaenoic acid), DHA (docosahexaenoic acid), and DPA (docosapentaenoic acid), appears to be associated with about a 30% reduction in the risk of developing the disease.
These data come from a study conducted at the University of Eastern Finland in Kuopio (Finland), as part of an epidemiological research project started in 1980. The work, published in the journal Diabetes Care, sheds new light on the association between fish consumption and diabetes risk.
Omega-3 and Type 2 Diabetes: An Unclear Link
Fish oil is rich in Omega-3, particularly DHA, EPA, DPA, and to a lesser extent ALA (alpha-linolenic acid), mainly found in seed oils. These molecules have several functions in the body and are known for their presence in cell membranes, for maintaining their integrity, and for their anti-inflammatory action. Omega-3s are also capable of lowering plasma triglyceride levels, reducing cardiovascular risk. These properties have suggested in recent years that Omega-3s might counteract the onset of type 2 diabetes. This is the most common form of diabetes and is characterized by poor response to insulin. One of the main predisposing factors for diabetes is overweight. However, the link between Omega-3 and diabetic pathology is quite contradictory. Some studies report evidence of the protective role of these polyunsaturated fatty acids, while others do not confirm the association. On the other hand, it has been confirmed that weight control, physical exercise, and linoleic acid intake are factors that reduce the risk of type 2 diabetes.
The Protective Action of DHA, EPA, and DPA
Researchers involved 2,212 healthy Finnish men, aged between 42 and 60 years at the start of the study (1984-1989). The serum concentrations of DHA, EPA, DPA, and ALA were analyzed for each subject. Additionally, mercury concentration—a metal that easily accumulates in fish and can modify the effects of Omega-3 in humans—was determined through hair analysis. During the follow-up period of about 19 years, 422 men developed type 2 diabetes. Dividing subjects into four groups based on four ranges of Omega-3 concentration, researchers observed that for men who had higher intake of EPA + DHA + DPA, the risk of developing diabetes was 33% lower compared to those with the lowest concentration. No associations were evident between diabetes onset and concentrations of ALA, EPA + DHA, or mercury.
Omega-3, varied diet, and exercise to prevent diabetes
According to the researchers, the observed effects may be due to Omega-3s’ ability to reduce adiposity, hypertension, and inflammation, all risk factors for type 2 diabetes. They probably also act on lipid and glucose metabolism. The results of this study thus confirm that a diet rich in fish high in Omega-3, such as salmon, sardines, anchovies, and herring, can help prevent diabetes, along with a proper lifestyle characterized by exercise, weight control, and good nutrition.
Source: Virtanen JK, Mursu J, Voutilainen S, Uusitupa M, Tuomainen TP. “Serum omega-3 polyunsaturated fatty acids and risk of incident type 2 diabetes in men: the Kuopio Ischemic Heart Disease Risk Factor Study.” Diabetes Care. 2014 Jan;37(1):189-96. doi: 10.2337/dc13-1504.
