Polycystic ovary syndrome (PCOS) is among the most common conditions experienced by women of reproductive age. Most commonly identified by high levels of androgens, insulin resistance, hyperinsulinemia, and long and/or irregular menstrual cycles, PCOS devastates a women’s physical, psychological, and emotional stability. It frequently is associated with infertility, cystic acne, obesity, hair loss, facial hair, and heavy bleeding during menstruation.

The etiology of PCOS is elusive and although we know of various contributing components, its exact cause in a given individual can be difficult to identify. However, as research evolves it has become increasingly clear that one of the primary etiologies of PCOS, leading to some of the most severe symptoms of the condition, is hyperinsulinemia (measured as fasting insulin >10μU/mL). Contrary to past understanding, PCOS is not a condition that only afflicts obese women with type 2 diabetes, although these are strong risk factors for PCOS and often, abdominal obesity is associated with symptom severity. While it is this population that perhaps helped uncover the association between insulin and sex hormones, there is a growing number of lean women who are also suffering from PCOS. In fact, nearly 50 percent of all women with PCOS are normal weight.

In all cases of PCOS, hyperinsulinemia stimulates an increase in gonadotrophin-releasing hormone (GnRH), reverses LH/FSH ratio (typically seen in a 1:1 ratio, but often >2:1 in PCOS), increases the production of testosterone, and decreases the production of sex hormone-binding globulin (SHBG). Interestingly, studies do show differences in endocrine measurements between obese and lean women with PCOS. In a study of 1269 patients with PCOS, in which 19 were underweight and 375 were lean, those who were of the lowest weight and BMI showed significantly higher postprandial insulin secretion after glucose intake in the oral glucose tolerance test.

Traditionally, hyperinsulinemia in PCOS has been managed with pharmaceuticals such as metformin, pioglitazone, statin drugs (to address the hyperlipidemia common in PCOS), and oral contraceptives; however, dietary changes and nutraceuticals can offer effective management of insulin and while improving overall health.

Low carb diets such as the ketogenic diet are one way to effectively lower fasting insulin levels, but rarely are low carb therapeutic diets presented as options to those with PCOS. A systematic review of the effects of low carb diets on fertility hormones included trials using ketogenic diets of less than 20 grams of carbohydrate per day with ad libitum energy intake, a very low energy diet with 34% carbohydrates, prescriptive energy-restricted diets with 40% carbohydrates, and 45% carbohydrate diets with an energy deficit. All diets resulted in significant improvements in fasting insulin, testosterone, and SHBG, and 40 percent of the women on the ketogenic diet became pregnant – a hugely successful clinical outcome for those with PCOS.

In a randomized controlled intervention study, 60 women with PCOS consumed either a conventional hypocaloric diet in which 15% of daily energy came from protein or a modified hypocaloric diet with a high-protein, low-glycemic load in which 30% of daily energy came from protein. After 12 weeks, mean testosterone decreased in both groups, but only the high-protein, low-glycemic-load diet resulted in a significant reduction of insulin and inflammatory markers (C-reactive protein). An 8-week prospective study using a low starch/low dairy diet in 10 women with PCOS, resulted in reductions of fasting insulin and body weight related to changes in both fasting and postprandial carbohydrate and fat oxidation. Finally, a ketogenic diet (<20 grams of carbohydrates) was employed in a 6-month pilot study seeking to determine its effects on hyperinsulinemia in women with PCOS and resulted in significant improvements in free testosterone, the LH/FSH ratio, and fasting insulin.

In addition to a low carb diet, inositol has emerged as one of few nutraceuticals with a successful track record when used to improve hyperinsulinemia and other hormonal imbalances associated with PCOS. Though technically a sugar alcohol, inositol is a component of cell membranes and help maintain structural integrity and intracellular signaling. It is also involved in the metabolism, transport, and breakdown of glucose, as well as its conversion to glycogen. And not surprisingly, it plays a role in the insulin-signaling pathways, helping to also encourage cellular uptake of glucose. Some studies have suggested that women with PCOS also have a deficiency of inositol since supplementation seems to improve ovarian function and other aspects of PCOS. Myo-inositol seems to improve metabolic markers well, whereas D-chiro-inositol focuses more on reducing hyperandrogenism. Both forms are helpful in rebalancing the hormones profile of PCOS.

Not only is PCOS a potentially devasting health condition that affects a women’s physical, emotional, and psychological health, but it resides as a member of yet a larger (and growing) class of health problems related to hormonal and metabolic imbalances. The good news is that this rising group of health conditions respond well to simple diet and lifestyle changes.