Effect of Whey Protein on Insulin Sensitivity and Glucose Metabolism in Women with and Without Polycystic Ovary Syndrome (PCOS)

This study focuses on the metabolic effects of whey protein isolate (WPI) supplementation glucose and insulin metabolism in women with and without Polycystic Ovary Syndrome (PCOS). Affecting up to 20% of post-puberty aged females around the world, PCOS is identified by three main symptoms: increased levels of androgens, irregular cycles, and the presence of ovarian cysts. Women with PCOS tend to be insulin resistant and have faulty insulin signaling. We hypothesize that because WPI has been seen to increase insulin sensitivity in type 2 diabetic populations, it will attenuate blood glucose and insulin levels and in women with PCOS. 15 women with PCOS and 14 women without PCOS (CON) underwent four 150-min oral glucose tolerance tests (OGTT): (i) baseline (no protein), (ii) Day 20 (iii) and Day 40 of WPI preload. Daily, participants consumed 35 g WPI 30 min before glucose load on test days. Plasma levels of glucose and insulin were assessed using a Biolis 24i chemistry analyzer. Additionally, variations in gene expression levels of glucose metabolism regulators, e.g., GLUT-4, were analyzed in 3T3-L1 cells under normal and PCOS-simulated conditions using qt-PCR before and after WPI supplementation. At baseline, both PCOS and CON women had similar fasting glucose levels (107.2 ± 19.54 and 101.14 ± 11.03 respectively). After 20 days of WPI supplementation, fasting glucose increased (103.75 ± 0.5 and 117.25 ± 9.60) but was attenuated by Day 40 (91.5 ± 0.71 and 94.5 ± 0.71). Furthermore, the baseline levels of GLUT-4 expression between women with PCOS (2.698 ± 0.145) and CON (2.188, ± 0.062) were not statistically different. Levels of gene expression post-supplementation with WPI are in the process of being measured. And lastly, plasma insulin levels are in the progress of being measured for both populations before and after supplementation. Preliminary analysis indicates that upon WPI supplementation, both groups glucose levels increased after 20 days, but was then attenuated by Day 40, with a slightly greater effect in the PCOS group compared to CON. Overall, our data indicates that WPI may be a potential dietary approach to better managing the symptoms of PCOS. Glanbia Nutritionals, Human Nutrition Research Funds, and Texas Woman's University.