Nutritional regulation of hepatic de novo lipogenesis in humans.

PURPOSE OF REVIEW: De novo lipogenesis (DNL) is a metabolic process occurring mainly within the liver, in humans. Insulin is a primary signal for promoting DNL; thus, nutritional state is a key determinant for upregulation of the pathway. However, the effects of dietary macronutrient composition on hepatic DNL remain unclear. Nor is it clear if a nutrition-induced increase in DNL results in accumulation of intra-hepatic triglyceride (IHTG); a mechanism often proposed for pathological IHTG. Here, we review the latest evidence surrounding the nutritional regulation of hepatic DNL. RECENT FINDINGS: The role of carbohydrate intake on hepatic DNL regulation has been well studied, with only limited data on the effects of fats and proteins. Overall, increasing carbohydrate intake typically results in an upregulation of DNL, with fructose being more lipogenic than glucose. For fat, it appears that an increased intake of n-3 polyunsaturated fatty acids downregulates DNL, whilst, in contrast, an increased dietary protein intake may upregulate DNL. SUMMARY: Although DNL is upregulated with high-carbohydrate or mixed-macronutrient meal consumption, the effects of fat and protein remain unclear. Additionally, the effects of different phenotypes (including sex, age, ethnicity, and menopause status) in combination with different diets (enriched in different macronutrients) on hepatic DNL requires elucidation.