Saturated fat stimulates obesity and hepatic steatosis and affects gut microbiota composition by an enhanced overflow of dietary fat to the distal intestine

Am J Physiol Gastrointest Liver Physiol. 2012 Sep 1;303(5):G589-99. doi: 10.1152/ajpgi.00488.2011. Epub 2012 Jun 14.

Abstract

We studied the effect of dietary fat type, varying in polyunsaturated-to-saturated fatty acid ratios (P/S), on development of metabolic syndrome. C57Bl/6J mice were fed purified high-fat diets (45E% fat) containing palm oil (HF-PO; P/S 0.4), olive oil (HF-OO; P/S 1.1), or safflower oil (HF-SO; P/S 7.8) for 8 wk. A low-fat palm oil diet (LF-PO; 10E% fat) was used as a reference. Additionally, we analyzed diet-induced changes in gut microbiota composition and mucosal gene expression. The HF-PO diet induced a higher body weight gain and liver triglyceride content compared with the HF-OO, HF-SO, or LF-PO diet. In the intestine, the HF-PO diet reduced microbial diversity and increased the Firmicutes-to-Bacteroidetes ratio. Although this fits a typical obesity profile, our data clearly indicate that an overflow of the HF-PO diet to the distal intestine, rather than obesity itself, is the main trigger for these gut microbiota changes. A HF-PO diet-induced elevation of lipid metabolism-related genes in the distal small intestine confirmed the overflow of palm oil to the distal intestine. Some of these lipid metabolism-related genes were previously already associated with the metabolic syndrome. In conclusion, our data indicate that saturated fat (HF-PO) has a more stimulatory effect on weight gain and hepatic lipid accumulation than unsaturated fat (HF-OO and HF-SO). The overflow of fat to the distal intestine on the HF-PO diet induced changes in gut microbiota composition and mucosal gene expression. We speculate that both are directly or indirectly contributive to the saturated fat-induced development of obesity and hepatic steatosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Dietary Fats / pharmacology*
  • Fatty Acids / pharmacology*
  • Fatty Liver / genetics
  • Fatty Liver / metabolism*
  • Gene Expression / drug effects
  • Intestinal Mucosa / metabolism
  • Intestines / drug effects*
  • Intestines / microbiology
  • Liver / metabolism
  • Metabolic Syndrome / genetics
  • Metabolic Syndrome / metabolism*
  • Metagenome
  • Mice
  • Mice, Inbred C57BL
  • Obesity / genetics
  • Obesity / metabolism*

Substances

  • Dietary Fats
  • Fatty Acids