The effect of dietary carbohydrate on genes for fatty acid synthase and inflammatory cytokines in adipose tissues from lean and obese subjects

J Nutr Biochem. 2008 Apr;19(4):237-45. doi: 10.1016/j.jnutbio.2007.02.013. Epub 2007 Jul 6.


Background: Hepatic de novo lipogenesis (DNL) is markedly stimulated in humans by low-fat diets enriched in simple sugars. However, the dietary responsiveness of the key enzyme controlling DNL in human adipose tissue, fatty acid synthase (FAS), is uncertain.

Hypothesis: Adipose tissue mRNA for FAS is increased in lean and obese subjects when hepatic DNL is elevated by a eucaloric, low-fat, high-sugar diet.

Design: Twelve lean and seven obese volunteers were given two eucaloric diets (10% vs. 30% fat; 75% vs. 55% carbohydrate; sugar/starch 60/40) each for 2 weeks by a random-order cross-over design. FAS mRNA in abdominal and gluteal adipose tissues was compared to hepatic DNL measured in serum by isotopic and nonisotopic methods. Adipose tissue mRNA for tumor necrosis factor-alpha and IL-6, which are inflammatory cytokines that modulate DNL, was also assayed.

Results: The low-fat high-sugar diet induced a 4-fold increase in maximum hepatic DNL (P<.001) but only a 1.3-fold increase in adipose tissue FAS mRNA (P=.029) and no change in cytokine mRNA. There was a borderline significant positive correlation between changes in FAS mRNA and hepatic DNL (P=.039). Compared to lean subjects, obese subjects had lower levels of FAS mRNA and higher levels of cytokine mRNA (P<.001).

Conclusions: The results suggest that key elements of human adipose tissue DNL are less responsive to dietary carbohydrate than is hepatic DNL and may be regulated by diet-independent factors. Irrespective of diet, there is reduced expression of the FAS gene and increased expression of cytokine genes in adipose tissues of obese subjects.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adipose Tissue / metabolism*
  • Blood Glucose / metabolism
  • Body Weight / drug effects
  • Cytokines / genetics*
  • Cytokines / metabolism
  • Dietary Carbohydrates / pharmacology*
  • Fatty Acid Synthases / genetics*
  • Fatty Acid Synthases / metabolism
  • Female
  • Humans
  • Inflammation / metabolism
  • Insulin / metabolism
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Lipogenesis / genetics
  • Male
  • Obesity / metabolism*
  • Thinness / genetics
  • Thinness / metabolism*
  • Tumor Necrosis Factor-alpha / genetics
  • Tumor Necrosis Factor-alpha / metabolism


  • Blood Glucose
  • Cytokines
  • Dietary Carbohydrates
  • IL6 protein, human
  • Insulin
  • Interleukin-6
  • Tumor Necrosis Factor-alpha
  • Fatty Acid Synthases