Purpose of review: The Δ5 desaturase (D5D) and Δ6 desaturase (D6D) are key enzymes in the metabolism of polyunsaturated fatty acids. This review aims to summarize recent advances towards understanding the relation of the activities of D5D and D6D to the development of type 2 diabetes.
Recent findings: Prospective studies that investigated fatty acid product-to-precursor ratios in blood as estimates of desaturase activity reported a clear inverse relation of D5D activity and a strong direct relation of D6D activity to diabetes incidence. Due to the prospective design and comprehensive confounder adjustment in these studies, confounding and reverse causation are unlikely explanations for these findings. Furthermore, studies on genetic variation in the FADS1 and FADS2 genes, which encode D5D and D6D, also point to an influence of D5D and D6D activity on glucose metabolism. The inverse relation of D5D activity and the direct relation of D6D activity to diabetes risk have been corroborated by a Mendelian randomization approach recently.
Summary: These recent studies suggest an important role of D5D and D6D activities for the development of type 2 diabetes. Factors which influence the activities of these desaturases are likely to be of public health relevance.