Favorable Metabolic Effects of a Eucaloric Lower-Carbohydrate Diet in Women with PCOS

Presentation Number: OR46-5
Date of Presentation: June 18th, 2013

Barbara Ann Gower*1, Paula C Chandler-Laney2, Fernando Ovalle2, Laura Lee Thompson Goree3, Ricardo Azziz4, Renee Desmond5, Wesley Granger5, Amy Miskimon Goss6 and G. Wright Bates5
1Univ of AL at Birmingham, Birmingham, AL, 2Univ of Alabama at Birmingham, Birmingham, AL, 3The Univeristy of Alabama at Bir, Birmingham, AL, 4Georgia Regents University, Augusta, GA, 5Univ. Alabama at Birmingham, 6University of Alabama at Birmingham

Abstract

For women with polycystic ovary syndrome (PCOS), elevated insulin may exacerbate symptoms by stimulating testosterone synthesis. Diet-induced reduction in circulating insulin may be an attractive non-pharmacological treatment for this population. This study was designed to determine if a modest reduction in dietary carbohydrate (CHO) content affects β-cell responsiveness and serum testosterone concentration in women with PCOS.

Thirty women with PCOS, defined using the NIH criteria, were enrolled in a cross-over diet intervention study.  Two eucaloric (weight-maintaining) diets were administered for 8 weeks in random order, separated by a 4-week wash-out period.  One diet, the “Standard” (STD) diet, was 55% energy from CHO, 18% energy from protein, and 27% energy from fat.  The other diet, the lower-CHO diet, had a macronutrient composition of 41:19:40. Energy requirements were determined by indirect calorimetery, with an activity factor of 1.35. 

β-cell responsiveness was assessed using mathematical modeling as the C-peptide response to glucose during a liquid meal test.  Insulin sensitivity was determined using insulin and glucose values throughout the meal test.  Insulin resistance was determined as HOMA-IR.  Total testosterone was assessed by immunoassay, and the lipid profile with a clinical analyzer using standard biochemical methods.

Paired t-test indicated that the lower-CHO diet induced significant decreases in basal β-cell response (PhiB), fasting insulin, fasting glucose, HOMA-IR, and all cholesterol measures, and significant increases in insulin sensitivity and dynamic (“first phase”) β-cell response; total testosterone decreased by 24% (P=0.05).  The STD diet induced a decrease in HOMA-IR and an increase in the total cholesterol-to-HDL-C ratio.  Across all data combined, the change in testosterone was positively associated with the changes in fasting insulin, PhiB, and insulin AUC (P<0.05).

In conclusion, in women with PCOS, modest reduction in dietary CHO in the context of a weight-maintaining diet has numerous beneficial effects on the metabolic profile that may lead to a decrease in circulating testosterone.

R01HD054960, UL1RR025777, P30DK56336, P60DK079626

 

Nothing to Disclose: BAG, PCC, FO, LLTG, RA, RD, WG, AMG, GWB