Adipose tissue α-linolenic acid is inversely associated with insulin resistance in adults

Background: There is emerging evidence of the beneficial effects of n-3 (omega-3) fatty acids (FAs) on cardiometabolic risk factors. Nevertheless, not much is known about the association between adipose tissue alpha-linolenic acid (ALA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) and insulin resistance. Objective: We determined the association between adipose tissue n-3 FAs (total n-3 FAs, ALA, and EPA plus DHA) and insulin resistance in healthy adults. Design: In this cross-sectional study, multivariable analyses were used to assess the association between adipose tissue FAs (ALA, EPA plus DHA, and total n-3 FAs) and the homeostasis model assessment of insulin resistance (HOMA-IR) in a subset of adult participants (n = 716; mean age: 58 y) from the Adventist Health Study-2 (AHS-2) cohort. Results: Compared with the lowest tertile, the third tertile (beta = -0.13; 95% CI: -0.24, -0.01) of adipose tissue ALA was inversely associated with the HOMA-IR. When stratified by waist circumference, ALA continued to be inversely associated [third tertile: beta = -0.17 (95% CI: -0.31, -0.02)] with the HOMA-IR in subjects with a waist circumference <= 88 cm in women or <= 102 cm in men but not in those with a larger waist circumference. No significant association was noted between adipose tissue EPA plus DHA and HOMA-IR. Conclusions: Higher adipose tissue ALA was inversely associated with insulin resistance in this cohort of healthy adult men and women. This finding appears to be more pronounced in individuals with a normal waist circumference.