Effects of dietary macronutrients on the hepatic transcriptome and serum metabolome in mice

Dietary macronutrient composition influences both hepatic function and aging. Previous work suggested that longevity and hepatic gene expression levels were highly responsive to dietary protein, but almost unaffected by other macronutrients. In contrast, we found expression of 4005, 4232, and 4292 genes in the livers of mice were significantly associated with changes in dietary protein (5%-30%), fat (20%-60%), and carbohydrate (10%-75%), respectively. More genes in aging-related pathways (notably mTOR, IGF-1, and NF-kappaB) had significant correlations with dietary fat intake than protein and carbohydrate intake, and the pattern of gene expression changes in relation to dietary fat intake was in the opposite direction to the effect of graded levels of caloric restriction consistent with dietary fat having a negative impact on aging. We found 732, 808, and 995 serum metabolites were significantly correlated with dietary protein (5%-30%), fat (8.3%-80%), and carbohydrate (10%-80%) contents, respectively. Metabolomics pathway analysis revealed sphingosine-1-phosphate signaling was the significantly affected pathway by dietary fat content which has also been identified as significant changed metabolic pathway in the previous caloric restriction study. Our results suggest dietary fat has major impact on aging-related gene and metabolic pathways compared with other macronutrients.