Serum fatty acid composition and insulin resistance are independently associated with liver fat markers in elderly men

To investigate the relationships of serum fatty acid (FA) composition and estimated desaturase activities with the liver fat marker alanine aminotransferase (ALT).546 Swedish elderly men of a population-based cohort participated in this cross-sectional study. FA composition was assessed in serum cholesterol esters to determine dietary fat quality (e.g. linoleic) and desaturation products (e.g. dihomo-gamma-linolenic acid). Desaturase indices, including stearoyl coenzymeA desaturase-1 (SCD-1), were calculated by FA product-to-precursor ratios.In linear regression analyses adjusting for lifestyle, abdominal obesity and insulin sensitivity, the dietary biomarker linoleic acid (n-6), but not n-3 FAs, was inversely related to ALT. Desaturation products including palmitoleic, oleic, gamma-linolenic and dihomo-gamma-linolenic acids, and Delta6-desaturase and SCD-1 indices were directly related to ALT (all p0.05). After further adjustment for factors previously linked to fatty liver (i.e. serum lipids, adiponectin concentrations), SCD-1 index (p=0.004) and insulin resistance (p0.0001) were independent determinants of ALT activity, whereas waist circumference, triglycerides, non-esterified FA and adiponectin were not.A low dietary intake of linoleic acid and elevated SCD-1 index may contribute to higher ALT activity in elderly men, even independently of obesity and insulin resistance.