title: Low-fat diet with omega-3 fatty acids increases plasma insulin-like growth factor concentration in healthy postmenopausal women.
abstract: 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.
authors.affiliation: Department of Food Science and Nutrition, Minneapolis, MN, USA.
authors.forename: Lindsay R
authors.initials: LR
authors.lastname: Young
authors.forename: Mindy S
authors.initials: MS
authors.lastname: Kurzer
authors.forename: William
authors.initials: W
authors.lastname: Thomas
authors.forename: J Bruce
authors.initials: JB
authors.lastname: Redmon
authors.forename: Susan K
authors.initials: SK
authors.lastname: Raatz
mesh_terms: D001786:Blood Glucose / Q000378:metabolism; D018592:Cross-Over Studies; D004032:Diet; D018752:Diet, Fat-Restricted; D059305:Diet, High-Fat; D004041:Dietary Fats / Q000008:administration & dosage / Q000494:pharmacology*; D015525:Fatty Acids, Omega-3 / Q000494:pharmacology*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D007333:Insulin Resistance; D018972:Insulin-Like Growth Factor Binding Protein 3 / Q000097:blood*; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008875:Middle Aged; D017698:Postmenopause; D012016:Reference Values
chemical_list: D001786:Blood Glucose; D004041:Dietary Fats; D015525:Fatty Acids, Omega-3; D007328:Insulin; D018972:Insulin-Like Growth Factor Binding Protein 3; D007334:Insulin-Like Growth Factor I
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