Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: Dietary Guidelines Adherence and Healthy Body Weight Maintenance Title: Low fat diet with omega-3 fatty acids increases plasma insulin-like growth factor concentration in healthy postmenopausal women

Authors
item Young, Lindsay -
item Kurzer, Mindy -
item Redmon, J. -
item Raatz, Susan
item Thomas, William -

Submitted to: Nutrition Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 29, 2013
Publication Date: July 7, 2013
Repository URL: http://handle.nal.usda.gov/10113/58096
Citation: Young, L.R., Kurzer, M.S., Redmon, J.B., Raatz, S.K., Thomas, W. 2013. Low fat diet with omega-3 fatty acids increases plasma insulin-like growth factor concentration in healthy postmenopausal women. Nutrition Research. 33:565-571.

Interpretive Summary: The insulin-like growth factor pathway is involved in the normal and abnormal growth of tissues. However, the role of nutrition in its regulation in normal individuals is not well-defined. The purpose of this study was to determine the effects of three test diets with varying types and amounts of dietary fat on circulating IGF-I, IGF binding protein-3 (IGFBP-3), insulin and glucose concentrations. Three test diets: high fat diet (HF; 40% energy as fat), low fat diet (LF; 20% energy as fat) and low fat, high omega-3 fatty acids diet (LFn3; 23% energy as fat) were tested in a randomized cross-over designed controlled dietary feeding trial in healthy postmenopausal women. Plasma IGF-I, IGFBP-3, insulin, glucose and ratio of IGF-I:IGFBP-3 concentrations were measured in response to the diets. 8 weeks of the LFn3 diet increased circulating IGF-I (P < 0.001) and IGFBP-3 (P = 0.01) and the LF diet increased IGFBP-3 (P = 0.04) resulting in trends towards an increased IGF-I:IGFBP-3 ratio with the LFn3 diet and a decreased IGF-I:IGFBP-3 ratio with the LF diet (P = 0.13 for both comparisons). Low fat diet with a high percentage of n-3 fatty acids may increase circulating IGF-I concentrations.

Technical Abstract: The insulin-like growth factor pathway plays a central role in the normal and abnormal growth of tissues; however, the nutritional determinants of insulin-like growth factor I (IGF-I) and its binding proteins in normal individuals are not well-defined. The purpose of this study was to determine the effects of three test diets with varying types and amounts of dietary fat on circulating IGF-I, IGF binding protein-3 (IGFBP-3), insulin and glucose concentrations. Design Three test diets: high fat diet (HF; 40% energy as fat), low fat diet (LF; 20% energy as fat) and low fat, high omega-3 fatty acids diet (LFn3; 23% energy as fat) were tested in a randomized cross-over designed controlled dietary feeding trial in healthy postmenopausal women. Plasma IGF-I, IGFBP-3, insulin, glucose and ratio of IGF-I:IGFBP-3 concentrations were measured in response to the diets. Insulin sensitivity was calculated using the homeostatic model assessment of insulin resistance (HOMA-IR). Results 8 weeks of the LFn3 diet increased circulating IGF-I (P < 0.001) and IGFBP-3 (P = 0.01) and the LF diet increased IGFBP-3 (P = 0.04) resulting in trends towards an increased IGF-I:IGFBP-3 ratio with the LFn3 diet and a decreased IGF-I:IGFBP-3 ratio with the LF diet (P = 0.13 for both comparisons). No statistically significant differences were detected between treatments at baseline or 8 weeks for IGF-I, IGFBP-3 or IGFBP-3. Insulin, glucose and HOMA-IR were not altered by the interventions. Conclusions Low fat diet with a high percentage of n-3 fatty acids may increase circulating IGF-I concentrations without adversely affecting insulin sensitivity in healthy individuals.

Last Modified: 4/16/2014
Footer Content Back to Top of Page