A Finnish study involving 2,189 healthy men aged 42-60 found that over 19 years, 417 men (19%) were diagnosed with type 2 diabetes. Those with high omega-6 polyunsaturated fatty acid concentrations in their blood were 46% less likely to develop diabetes. When analyzed, it turned out that this association depended on linoleic and arachidonic acid concentrations only; high serum gamma-linolenic and dihomo-γ-linolenic acid concentrations were linked to a higher risk.
The serum linoleic acid concentration is determined by the person's diet, and the main sources of linoleic acid are vegetable oils, nuts and seeds. Arachidonic acid is present in meat and eggs; however, the human body can also make arachidonic acid from linoleic acid.
Gamma-linolenic acid and dihomo-γ-linolenic acid are mainly formed in the human body from linoleic acid, but their concentrations in serum are very low.
Linoleic acid is the most common omega-6 fatty acid, and has been linked to a reduced risk of cardiovascular diseases as well as type 2 diabetes.
Teymoor Yary, Sari Voutilainen, Tomi-Pekka Tuomainen, Anu Ruusunen, Tarja Nurmi, Jyrki K Virtanen 2016. Serum n-6 polyunsaturated fatty acids, delta-5- and delta-6-desaturase activities and risk of incident type 2 diabetes in men: The Kuopio Ischaemic Heart Disease Risk Factor Study. American Journal of Clinical Nutrition, Published online March 24, 2016 http://ajcn.nutrition.org/content/early/2016/03/23/ajcn.115.128629.abstract