A high-fat eucaloric diet induces reprometabolic syndrome of obesity in normal weight women

Abstract

Objective We examined the effects of one month of a eucaloric, high-fat (48% of calories) diet (HFD) on gonadotropin secretion in normal weight women to interrogate the role of free fatty acids and insulin in mediating the relative hypogonadotropic hypogonadism of obesity. Methods Eighteen eumenorrheic women (BMI 18-25 kg/m2) were studied in the early follicular phase of the menstrual cycle before and after exposure to a HFD with frequent blood sampling for LH and FSH, followed by an assessment of pituitary sensitivity to GnRH. Mass spectrometry-based plasma metabolomic analysis was also performed. Paired testing and time series analysis were performed as appropriate. Results Mean endogenous LH (unstimulated) was significantly decreased after the HFD (4.3 ±1.0 vs 3.8 ± 1.0, P<0.01); mean unstimulated FSH was not changed. Both LH (10.1 ± 1.0 vs 7.2 ± 1.0, P<0.01), and FSH (9.5 ± 1.0 vs 8.8 ± 1.0, P<0.01) response to 75 ng/kg of GnRH were reduced after the HFD. Mean LH pulse amplitude and LH interpulse interval were unaffected by the dietary exposure. Eucaloric HFD exposure did not cause weight change. Plasma metabolomics confirmed adherence with elevation of fasting free fatty acids (especially long-chain mono-, poly- and highly-unsaturated fatty acids) by the last day of the HFD. Conclusion One-month exposure to a HFD successfully induced key reproductive and metabolic features of Reprometabolic Syndrome in normal weight women. These data suggest that dietary factors may underly the gonadotrope compromise seen in obesity related subfertility and therapeutic dietary interventions, independent of weight loss, may be possible.