Optimal body weight
Attaining optimal body weight and proportional lean (muscle mass) to fat ratio, and minimizing visceral body fat have all been described to improve insulin resistance measures in PCOS women, improving ovulation rates and symptoms related to excess androgen production. Generally, a sensible weight loss program is indicated.
Minimise visceral fat
Visceral fat is closely linked to insulin resistance and PCOS, even in lean PCOS women. Visceral fat is the fat surrounding internal organs mainly around the abdomen. Visceral fat is harder to lose because it is deeply embedded in the body. A person can be in a healthy weight range and still have too much intra-abdominal fat around the internal organs. The liver metabolises visceral fat and releases it into the bloodstream as cholesterol. Eating more than 30% fat results in an increase of visceral fat.
The high protein diet
A study with PCOS women comparing a high protein diet (30% protein and 40% carbohydrate) led to weight loss, improvement in insulin resistance, and a degree of normalization of menstrual function. However, in the longer term the benefits of a calorie restricted versus protein diet are of equal benefit.i
Low glycemic index foods and inclusion of healthy fibre
The type of carbohydrate consumed is just as important as the amount consumed. By substituting simple carbohydrates with complex carbohydrates, and the addition of fibre to the diet, especially guar gum and Konjac-mannan; insulin resistance is improved.ii
A diet rich in polyphenols
Green tea polyphenols, have known effects on hormones. These polyphenols enable Vitamin E to be regenerated, preventing long-term cardiovascular disease in insulin resistant patients and increasing HDL (good) cholesterol levels. A polyphenol from green tea was found to bind to receptors and reduce the risk for ovarian hyperstimulation syndrome (OHSS) in PCOS patients.
Three natural polyphenols –quercetin, myricetin, and catechingallate – were found to interact directly with the glucose transporter in fat cells and muscle cells improving glucose uptake in cells.
Natural sources of polyphenols include green tea, grape skin extracts (especially red grapes, and red wine), olive oil, flaxseed, apples, onions, garlic, and soybeans. Quercetin can also be taken as a supplement.
Poly and monounsaturated fats
High fat diets lead to high levels of Free Fatty Acids (FFA) in the blood, which compounds insulin resistance and decreases muscle cell insulin sensitivity. Studies demonstrate an improvement of insulin resistance and upper body fat loss when a high monounsaturated fat diet replaced a high saturated fat diet.iii However, this beneficial effect disappeared when total fat intake exceeded 38% of total caloric intake. Examples of foods rich in monounsaturated or polyunsaturated fat include liquid oils from olives, canola, soybeans, corn, flaxseed, sunflower, and peanuts. Also, fats derived from nuts, seeds, and deep-sea fish are from the same category.
The Mediterranean diet
The “Mediterranean-style” (MS) diet consists of additional fruits, vegetables, and nuts, with an increased whole grain and olive oil intake. In one study on PCOS women 50 out of 90 patients were no longer classified as having metabolic syndrome. They also had a lower BMI, lower triglycerides, higher HDL, and less insulin resistance. This was in part attributed to a lower saturated fat intake.
Soybeans and Inositol
Whole soybeans improve lipid abnormalities in patients with insulin resistance due to their phytoestrogen content and high soluble fibre content, thus lowering LDL and increasing HDL. Diets rich in soybean content can improve glycaemic control in diabetic (type2) patients by improving insulin resistance parameters.
Dietary supplementation of inositol was evaluated in a double-blind, placebo controlled study in 281 women with PCOS. The treatment group lost weight and had more ovulations during the study period than controlled patients, although no significant differences in insulin parameters were found between the groups.
B vitamins and the Homocysteine connection
Homeocysteine (Hcy) is an intermediate formed during the breakdown of amino acids (specifically methionine). The accumulation of Hcy is due to defects in enzymatic pathways, commonly due to folic acid and vitamin B12 deficiency. Increased levels of Hcy are associated with increased insulin levels and several studies demonstrated increased Hcy levels in PCOS patients.iv
Elevated levels of Hcy are associated with vascular inflammation, atherosclerosis, increased rates of miscarriage, and poor reproductive performance. Therefore reducing elevated Hcy could improve these parameters. Strategies for reducing Hcy may include folic acid and vitamin B12 supplementation.
Supplementation of B group vitamins, especially folic acid has been shown in specific patient populations (such as smokers, diabetics, and thrombophilic patients) to lower cardiovascular risk and to improve reproductive performance, especially in hyperhomocysteinemia.
Betaine and HomoCysteine
Several studies have shown that elevated Hcy levels in insulin resistant patients may be reduced by betaine supplementation. Folic acid (as folate), by itself, and in conjunction with vitamin B12, has consistently shown Hcy-lowering effects in many studies. Betaine may enhance Hcy metabolism even when folic acid levels are insufficient and lowered insulin levels, after 1 month of folic acid (5mg per day) and vitamin B12 (0.5mg per day).
Studies in 96 insulin resistance PCOS women with a combination of vitamin B1 50mg, vitamin B12 (as cobalamin) 0.5mg, folic acid 0.4mg, and trimethyglycine (betaine) 1g per day for three infertility treatment cycles revealed significant reductions in Hcy levels.
Niacin (vitamin B3), has been documented as an effective nutritional supplement for the treatment of the dyslipidemia of metabolic syndrome. PCOS is associated with insulin resistance and male-pattern upper body fat accumulation. This obesity pattern is associated with elevated fatty acids, and niacin alleviates these high levels.
Vitamin A reduced body weight and improved glucose tolerance in mice. Diets higher in vitamin A showed an inverse relationship with insulin resistance, hence the importance of verifying normal vitamin A status in PCOS women.
Cinnamon improves insulin sensitivity, and may be of potential use in PCOS hypersecretion of androgens. Cinnamon administration prevented the development of insulin resistance at least in part by enhancing insulin signaling in skeletal muscle.
Available research suggests an association between magnesium deficiency and insulin resistance. Magnesium deficiency was a relatively common finding in both overweight adults and patients with Type 2 diabetes. A study conducted in PCOS women looked at the status of serum calcium and magnesium, and their ratio. Significantly lower serum magnesium ion and total body magnesium, and higher serum Ca²+/Mg²+ ratios were found in PCOS women.
Calcium and Vitamin D
Another study found relatively low levels of vitamin D and high parathyroid hormone. Treatment with vitamin D and calcium normalized cycles in women. Calcium supplementation (1500mg/day for 6 weeks) improved insulin sensitivity in diabetic, insulin resistant patients; these patients did not have PCOS. Vitamin D may have an anti-inflammatory role.v
Low levels of chromium lead to insulin resistance. Studies support the use of chromium-nicotinic acid complex, chromium-rich brewer’s yeast or chromium picolinate.
PCOS is a generalized systemic disease state, with insulin oxidative stress being central to the pathophysiology of the ovarian aspects of the syndrome. As such, nutritional balance in terms of oxidation-reduction is extremely important for both short-term results of infertility treatment and long-term health consequences.
Increased oxidative stress and decreased antioxidant capacity in women with PCOS could be a contributing factor to the increased risk of cardiovascular disease in addition to risk factors such as insulin resistance, hypertension, obesity and dyslipidemia.
Elevated Hcy is also associated with oxidative stress, and, as previously mentioned, is correlated with insulin resistance in PCOS patients. These studies form a logical theoretical basis for the supplementation of antioxidants to the diet of patients with insulin resistant PCOS.
Essential fatty acids
Fish oil is rich in omega-3 essential fatty acids; two active forms are eicosapentaenoic acid (EPA) and docosahexaenoic (DHA). Several studies have shown improved insulin sensitivity, decreased inflammatory markers, and improved blood lipids after EPA/DHA supplementation.
Gamma linolenic acid from borage oil or evening primrose oil, is an omega-6 fatty acid normally synthesized from linolenic acid. This fatty acid is more efficacious when administered with EPA/DHA than on its own. Gamma linolenic acid has been found to have anti-inflammatory effects, and, importantly for PCOS patients, can inhibit 5-alpha reductase, thus reducing skin dihydrotestosterone.
Alpha – lipoic acid
Alpha-lipoic acid was examined in animal and clinical studies for its ability to improve insulin sensitivity. Using a high-fructose diet model in rats, α-lipoic acid improved both insulin sensitivity and decreased oxidation parameters. In clinical studies in humans, both intravenous and oral administration of α-lipoic acid increased insulin stimulated glucose disposal (mean improvement 27% in 74 patients treated with 600-1800 mg/day for 4 weeks).
N-acetyl cysteine (NAC) is an amino acid. Administration of this compound improves insulin sensitivity and can increase glutathione (an antioxidant produced within the body). Glutathione reduces plasma homocysteine. A study investigating the effect of NAC on hormone and lipid profile and Hcy levels in insulin resistant PCOS women showed that NAC reduced Hcy levels and improve lipid profiles making it an alternative to other treatments. Another study with NAC in insulin resistance PCOS women demonstrated a significant reduction in insulin resistance, testosterone levels, and in free androgen index, when 37 PCOS patients were treated with 1800 mg/day.
The clomiphene-NAC treated group had a significantly higher ovulation rate than the clomiphene-placebo group. These studies highlight the potential of NAC in treating PCOS.
Polycystic ovary syndrome is a complicated metabolic syndrome which has insulin resistance as central to its manifestations. Nutritional status has a critical effect on the short- and long-term effects of the syndrome. Utilizing dietary recommendations and lifestyle modifications to optimize body weight and visceral fat status, both short-term fertility goals and long-term vascular health may be enhanced.
|i||Stamets K., Taylor D.S., Kunselman A., et al. (2004) A randomized trial of the effects of two types of short-term hypocaloric diets on weight loss in women with Polycystic ovary syndrome. Fertil. Steril. 81:630-637.|
|ii||Vuksan V., Sievenpiper J.L., Owen R., et al (2000) Beneficial effects of viscous dietary fiber from Konjac-mannan in subjects with insulin resistance syndrome: results of a controlled metabolic trial. Diabetes care 23: 9-14|
|iii||Walker K.Z., O’Dea K., and Johnson L. (1996) Body fat distribution andnon-insulin dependant diabetes: comparison of a fibre rich, high carbohydrate, low fat (23%) and a 35% fat diet in monounsaturated fat. Am J. Clin. Nutr. 63: 254:260.|
|iv||Schwab U., Torronen A., Toppinen L., “Betaine Supplementation decreases plasma homocysteine concentrations but does not effect body weight, body composition, or resting energy expenditure in humans subjects. Am Journal of Clinical Nutrition 76:961-967.|
|v||Thys-Jacobs S., Donovan D., Papadopoulos A., Sarrel P., and Bilezikian J.P. (1999) Vitamin D and calcium dysregulation in the polycystic ovarian syndrome. Steroids 64:430-435.|