While overweight or obese people often have high insulin levels and insulin resistance or metabolic syndrome, women with PCOS who are not obese can nevertheless have insulin resistance and metabolic syndrome. So abnormalities in blood sugar metabolism may contribute to PCOS development. Diet quality and nutritional needs are no doubt involved. High insulin levels may suppress ovulation, cause drops in blood sugar, increase risk of weight gain, and affect sex-hormone ratios. There is evidence that high insulin levels can promote high androgen levels and that high androgen levels can promote insulin resistance. The question is “which came first, the chicken or the egg?” -it can be difficult to know. Insulin might stimulate androgen production because 10 ovaries have insulin receptors. 2) insulin decreases the serum level of sex hormone binding globulin (SHBG), the primary protein that carries estradiol or testosterone to cell membrane receptors in target tissues. When SHBG levels decrease, more unbound testosterone is allowed to circulate, amplifying its effects. 30 insulin-like growth factors (IGF) may stimulate production of androgens and growth of the ovaries. IGFs are proteins with similarities to insulin. among the many factors that may cause IGF-1 variations are excess stress, nutritional needs, excess weight, low estrogen, and xenobiotic intake. IGF-1 may work with luteinizing hormone (LH) and insulin to produce androgen hormones. Insulin reduces levels of the primary binding protein for IGF (IGVBP-1), making more IGF available. 4) Insulin may affect the anterior pituitary by increasing LH, creating a relative decline in follicle stimulating hormone (FSH) which leads to ovarian tissue thickening and increasing androgen production. 5) elevation of androstenedione and DHEA (dehydroepiandrosterone, an adrenal hormone with about one fifth the potency of androsterone, and androgen product) can have androgen-producing effects. Many women with PCOS have a significant increase in adrenal androgen levels in addition to increased ovary levels. The adrenal component may be more prevalent in younger and leaner women.
Long term of oral contraceptives (a common medical treatment for PCOS) can contribute to insulin resistance. Reduced levels of nutrients such as glutathione, vitamin C and vitamin E plus GST (glutathione-S-transferase) enzyme have been found in non-obese women with PCOS and are unrelated to insulin status. A number of other nutrient deficiencies are found in women with the syndrome. Obviously, many components can contribute to PCOS. there is evidence that environmental factors can play a role. some research, for example, indicates that exposure to bisphenol A (BPA), a chemical used in plastics and linings of food cans and known to be a hormone disruptor, could be a contributing cause. Blood levels of BPA were more than 30% higher in overweight women with PCOS and nearly 60% higher in lean women with the syndrome compared with a control group. As BPA levels increases, so did concentrations of testosterone and androstenedione. There is also an association between BPA levels and insulin resistance. BPA is being replaced by other chemicals, but they are turning out to be just as bad or even worse. Excessive stress triggers stress hormones, especially cortisol, which place glucose stores on “red alert” for the fight, flight, or freeze response. High insulin levels tend to increase cortisol levels so a woman’s body may be flooded with both insulin and cortisol.
Therefore, possible basic causes of PCOS include: 1) Excess weight gain. 2) Insulin resistance. 3) Ovarian dysfunction (low estrogens and high androgens). 4) Adrenal dysfunction. 5) Hypothalamic-pituitary axis dysfunction (elevated LH and lower FSH). 6) environmental factors (including exposure to toxins such as hormone disruptors). All of these can benefit from nutritional and other lifestyle improvements.
Nutrition News and Views, May/June 2015, Vol. 19, No. 3
by Judith A. DeCava, CNC, LNC