DR. DAVID K. SHEFRIN
POLYCYSTIC OVARY SYNDROME (PCOS) AND LOW CARBOHYDRATE DIET
Polycystic ovary syndrome (PCOS) is a complex, multi-faceted syndrome characterized clinically by high levels of androgen hormones (such as testosterone), high levels of insulin, lower abdominal obesity, acne, masculine hair growth patterns, and menstrual irregularities. A review of some of the scientific literature regarding PCOS suggests that one effective strategy for ameliorating the symptoms of PCOS may indeed be a low carbohydrate diet that tightly controls blood glucose and insulin levels.
While the underlying reason is still not entirely clear, research shows that women with PCOS develop very significant insulin resistance, meaning that their tissues become less sensitive to the message insulin sends to them to take glucose from the blood and move it into tissues to be used for energy. There is recent evidence suggesting that, in fact, women with PCOS may have a defect in the normal pattern of cell signaling that takes place when insulin binds to the receptors of cells. In any case, a scenario of reduced insulin sensitivity is also characteristic of type II diabetes mellitus, and indeed there is research suggesting that women with PCOS are at a significantly increased risk of developing type II diabetes. High levels of insulin resistance in patients with PCO are also associated with low levels of HDL-cholesterol, the ‘good cholesterol’, and might help explain part of the increased risk patients with PCO have of cardiovascular disease. Other contributing factors to this increased risk of cardiovascular disease in patients with PCO may be chronic inflammation, as evidenced by increased levels of the inflammatory marker C-reactive protein, and increased levels of oxidative stress.
Another important aspect of high blood insulin levels is the relationship between high insulin and the lowered levels of sex hormone binding globulin (SHBG) it may cause. SHBG is the protein made by the body to help remove estrogens and testosterone from the circulation, limiting the effects of these powerful hormones. Both high blood glucose levels and high blood insulin levels are associated with decreased levels of SHBG, and both insulin and insulin-like growth factor have been shown to down regulate the liver cells’ production of SHBG. In one study of women with and without PCOS placed on a low calorie diet, both groups of women showed more than doubled amounts of SHBG, decreased insulin, and also importantly for women with PCOS, a decrease in testosterone. A similar protocol, when carried out for 6-7 months also resulted in more normalized menstrual cycles and increased fertility.
There is a lot to learn from research done in the area of glucose control with patients of PCOS, and though some studies emphasize pharmaceutical prescriptions over the effects of a low carbohydrate diet, they do illustrate how effective glucose control can be in the treatment of patients with PCOS. For example, a recent study has shown that women with PCOS who are treated with metformin, a drug used to decrease liver glucose production and possibly increase insulin receptor sensitivity, saw somewhat decreased levels of androgen production. When this approach was combined with a high protein-low carbohydrate diet in teenage women with PCOS, 10 of 11 subjects resumed a normal menstrual cycle, on average after 10.5 months of treatment. In addition, other markers of PCOS were improved, with increased estrogen and progesterone, a trend toward decreased testosterone, and decreased total cholesterol.
In another study acarbose, a medication that slows the release of glucose from the gastrointestinal tract to the body, was given to patients with PCOS. After three months of treatment the patients with PCOS showed a significant reduction of hirsutism (male patterns of hair growth) and acne. The patients also experienced a lower release of insulin in response to a glucose challenge, a reduction in the levels of the androgen hormones testosterone and androstenedione, an increase in SHBG, and 8 of the 30 patients with PCOS began to have regular menstrual cycles.
While pharmaceutical approaches, alone or combined with a low carbohydrate diet are certainly helpful, it is also important to emphasize the benefit that may be obtained exclusively by following a diet low in refined carbohydrate. This is ultimately the strategy that is the least expensive and teaches the patient that they have the ability, to a large extent, to maintain their health by choices made in daily living. In this light, the results of an Italian study, the DIANA study, are especially interesting.
While this study did not use a study group of women diagnosed with PCOS (though some of the women in the study may also have been women with PCOS), the study’s subjects were 104 women with the highest levels of testosterone out of 312 women screened. Thus, like women diagnosed with PCOS, these subjects tended to high androgen levels. The treatment group of the study received a highly controlled diet rich in whole grain cereals, seeds (such as flax), berries, cruciferous vegetables, and other vegetables. They also increased their amounts of fish, seaweed, and olive-oil intake, while consuming greater quantities of legumes and soy products. Meat, eggs, and dairy were only consumed once a week and refined carbohydrates, such as white bread, processed white flour and sucrose were discouraged. After eighteen weeks, the subjects with this modified diet showed a 25% increase in SHBG, a 19.5% decrease in testosterone, and a significant decrease in the amount of insulin released in response to a glucose challenge, compared to controls. The diet in the intervention group also accounted for a loss of about 7.7lbs, which may have actually been the most important factor in the reduction of testosterone.
In short, given the prevalence of high insulin levels in women with PCOS and the reduction in androgen levels that accompany glucose and insulin control, it is very reasonable to focus on controlling glucose and insulin as a clinical strategy in treating women with PCOS. While some pharmaceutical interventions, such as metformin and acarbose are helpful in this regard, the basis of the approach is best based upon sound dietary choices that substantially restrict refined carbohydrates, include high quality protein, and provide omega-three and monounsaturated fatty acids.
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