Low-fat diet with omega-3 fatty acids increases plasma insulin-like growth factor concentration in healthy postmenopausal women

Nutr Res. 2013 Jul;33(7):565-71. doi: 10.1016/j.nutres.2013.04.011. Epub 2013 May 30.


The insulin-like growth factor pathway plays a central role in the normal and abnormal growth of tissues; however, nutritional determinants of insulin-like growth factor I (IGF-I) and its binding proteins in healthy individuals are not well defined. Three test diets-high-fat diet (40% energy as fat), low-fat diet (LF; 20% energy as fat), and a diet with low fat and high omega-3 fatty acid (LFn3; 23% energy as fat)--were tested in a randomized crossover designed controlled feeding trial in healthy postmenopausal women. Plasma IGF-I, IGF binding protein-3 (IGFBP-3), insulin, glucose, and ratio of IGF-I/IGFBP-3 concentrations were measured in response to diets. Insulin sensitivity was calculated using the homeostatic model assessment of insulin resistance We hypothesized that IGF-I, insulin, and glucose concentrations would decrease and IGFBP-3 concentration would increase in response to the low-fat diets. Eight weeks of the LFn3 diet increased circulating IGF-I (P < .001) and IGFBP-3 (P = .01) and the LF diet increased IGFBP-3 (P = .04), resulting in trends toward an increased IGF-I/IGFBP-3 ratio with the LFn3 diet and a decreased IGF-I/IGFBP-3 ratio with the LF diet (P = .13 for both comparisons). No statistically significant differences were detected between treatments at baseline or 8 weeks for IGF-1, IGFBP-3, or the ratio of IGF-1/IGFBP-3. Insulin, glucose, and the homeostatic model assessment of insulin resistance were not altered by the interventions. Low-fat diet with high n-3 fatty acids may increase circulating IGF-I concentrations without adversely affecting insulin sensitivity in healthy individuals.

Keywords: Diet; Dietary fat; GH; Glucose; HOMA-IR; IGF binding protein-3; IGF binding protein-3 (IGFBP-3); IGF-I; IGFBP-3; Insulin; Insulin-like growth factor I (IGF-I); Omega-3 fatty acids; growth hormone; homeostatic model assessment–insulin resistance (fasting insulin [mUL] × fasting glucose [mmol/L] 22.5); insulin-like growth factor I.

Publication types

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

MeSH terms

  • Blood Glucose / metabolism
  • Cross-Over Studies
  • Diet*
  • Diet, Fat-Restricted
  • Diet, High-Fat
  • Dietary Fats / administration & dosage
  • Dietary Fats / pharmacology*
  • Fatty Acids, Omega-3 / pharmacology*
  • Female
  • Humans
  • Insulin / blood
  • Insulin Resistance
  • Insulin-Like Growth Factor Binding Protein 3 / blood*
  • Insulin-Like Growth Factor I / metabolism*
  • Middle Aged
  • Postmenopause
  • Reference Values


  • Blood Glucose
  • Dietary Fats
  • Fatty Acids, Omega-3
  • Insulin
  • Insulin-Like Growth Factor Binding Protein 3
  • Insulin-Like Growth Factor I