Diet and polycystic ovary syndrome. (Nutrition and Disease).
Author/s: Martha McKittrick
As nutrition educators, it is likely that we have encountered a patient with polycystic ovary syndrome (PCOS) whether or not we were aware of it. Up to 10% of all women have PCOS. The complaints of obesity and/or dyslipidemia may be what prompt the patient to seek nutritional counseling. Approximately 50% to 60% of women with PCOS are obese (1,2) and 60% have dyslipidemia (high triglycerides and low high-density lipoprotein [HDL] levels). (3) Nutrition educators must be aware of the important role that diet and lifestyle counseling play in working with women with PCOS. The purpose of this article is threefold–to provide basic background information on PCOS, to discuss the role of insulin resistance in PCOS, and to provide practical lifestyle and dietary guidelines for the management of the woman with PCOS.
What Is Polycystic Ovary Syndrome?
PCOS is a complex hormonal disturbance that affects the entire body and has numerous implications for general health and well-being. It is the most common cause of infertility and, if left untreated, can lead to increased risk of heart disease and diabetes. Three key features characterize PCOS: (1) the presence of hyperandrogenism (excess male hormones), (2) chronic anovulation (infrequent or absent menstrual periods), and (3) exclusion of other etiologies that can mimic the syndrome (ie, congenital or nonclassical adrenal hyperplasia). (1)
PCOS is not a disease but rather a syndrome. A syndrome is defined as a group of symptoms and physical findings. The 3 most common symptoms of PCOS are irregular periods, hirsutism (excess body and facial hair), and obesity. Other symptoms include alopecia (thinning hair) and acne. In addition to the hormonal and clinical changes associated with this condition, vaginal ultrasound may show enlarged or normal sized ovaries with multiple small cysts (polycystic appearing ovaries [PAO]). However, a woman does not have to have PAO to have PCOS because not all women with PCOS exhibit all of the symptoms.
The exact etiology of PCOS is not known. Dr Walter Futterweit, Clinical Professor of Medicine in the Division of Endocrinology at The Mount Sinai School of Medicine in New York City, has been working with women with PCOS for the past 25 years. He believes the following characteristics are involved in PCOS:
* There is a strong genetic tendency for PCOS. Those affected often have both male and female relatives with adult-onset diabetes, obesity, elevated blood triglycerides, high blood pressure and female relatives with infertility, hirsutism, and menstrual problems.
* Insulin resistance and compensatory hyperinsulinemia play a role in the majority of patients. There is increasing data that hyperinsulinemia produces the hyperandrogenism of PCOS by increasing ovarian androgen production. (4-6)
* Normal ovarian function relies on appropriate signals from two hormones secreted from the pituitary gland–follicle stimulating hormone (FSH) and luteinizing hormone (LH). In PCOS, there is hyperstimulation of pituitary LH. The high levels of LH and insulin stimulate the ovary to produce excess male androgens. Obesity magnifies this effect.
* Intrinsic enzymatic abnormalities have been demonstrated in the ovaries as well as the adrenal glands, which are a significant factor in the syndrome.
* The higher centers in the brain may also be implicated in the characteristics of the syndrome. Both hypothalamic and pituitary dysfunction have been reported.
Treatment of Polycystic Ovary Syndrome
Traditional treatments of PCOS have been aimed toward the individual symptoms. Because the immediate culprit in the patient’s endocrine symptoms (ie, hirsutism, irregular periods) stem from elevated levels of androgens, the patient is often treated with anti-androgen medications (birth control pills, spironolactone, and occasionally finasteride, etc). However, since insulin resistance and hyperinsulinemia are a major underlying factor in PCOS for many women, treatment may also be aimed at lowering elevated insulin levels. (1,4-6) Both weight loss and exercise have been proven to lower insulin levels, thereby leading to a decrease in androgens and an improvement of symptoms. The nutrition counselor can therefore play a key role in the treatment of PCOS by providing guidance in the areas of weight loss and exercise. It has been also been demonstrated that insulin-sensitizing agents (ISA), such as metformin, can ameliorate hyperandrogenism by reduction of ovarian enzyme activity that results in male hormone production. (4,5) However, experts stress that ISA should not be a reflex treatment for all women with PCOS. More research is needed in this area to define the role of ISA.
Although insulin resistance is not the only causative factor in PCOS, it has been proved to be an important one for the majority of women. The rest of this article explores the role that insulin resistance plays in PCOS. The role of weight loss, diet, and exercise and their effects on insulin levels are also discussed.
Insulin Resistance in Polycystic Ovary Syndrome
Insulin resistance is a term that is used to describe the resistance of the cells to the action of the pancreatic hormone insulin. When the cells are resistant to the action of insulin, glucose is not removed from the blood stream to the cells where it can be used for energy. The compensatory mechanism for insulin resistance is for the pancreas to oversecrete insulin–the state known as hyperinsulinemia.
The exact mechanism of insulin resistance in PCOS is unclear. One theory is that the muscle and fat cells of a woman with PCOS are insulin resistant, whereas other types of cells and organs remain sensitive to insulin. As a result, the pituitary and ovaries of a patient who is insulin resistant may be stimulated by higher levels of insulin. The consequences cause elevated hormone levels of androgens and LH. (2,7) This state is called selective resistance. It is believed that up to 80% of women with PCOS are insulin resistant. (2) Studies have proved that women both who are lean and who are overweight can be insulin resistant. However, the insulin resistance is exacerbated in obesity. (1,7)
Potential Complications of Polycystic Ovary Syndrome
Aside from menstrual dysfunction, possible infertility, and skin and scalp manifestations, women with PCOS have a high prevalence of more serious metabolic and cardiovascular risk factors. There are numerous data indicating that insulin resistance and hyperinsulinemia not only potentiate androgen excess but also may lead to an increased incidence of other disorders, including impaired glucose tolerance (or type 2 diabetes), high triglycerides, low blood HDL cholesterol, hypertension, and atherosclerosis. This cluster of disorders is similar to the syndrome called “syndrome X.” (5,6)
Dr Gerald Reavan coined the term syndrome X in 1988. Syndrome X is characterized by high levels of insulin and represents a major cause of coronary heart disease. The risk factors for syndrome X include impaired glucose tolerance, elevated triglycerides, low HDL, slow clearance of fat from the blood, elevated blood pressure, increased small dense low-density lipoprotein (LDL), and increased clotting. It is believed that women with PCOS may have similar risk factors due to presence of hyperinsulinemia.
It is now known that PCOS is not just a gynecologic disorder, but rather it is a metabolic-cardiovascular disorder that affects multiple systems whose pathogenic element is insulin resistance and/or hyperinsulinemia. It is important that women with PCOS be educated on its potential long-term health effects and be guided toward changing their lifestyles to reduce their risk factors.
Factors Affecting Insulin Resistance
Obesity is associated with an increase in insulin resistance and is present in 50% to 60% of women with PCOS. Many women with PCOS have had a weight problem for most of their lives, whereas others report a sudden weight gain for no apparent reason. With PCOS, there is an increased tendency for central distribution of fat. (1) Such an increased waist-to-hip ratio has an even greater effect on exacerbating insulin resistance than less localized obesity. (7)
Why do women with PCOS have an increased prevalence of obesity? The exact answer is unclear; however, there are several possible explanations. Dr Futterweit believes that these women have a more difficult time losing weight compared with women without PCOS, possibly due to increased carbohydrate cravings. Carbohydrate cravings and hunger are common in women with PCOS and may result from, at least in part, high levels of insulin. In addition, it is not uncommon to see women with PCOS with depression and low self-esteem, which can contribute to emotional eating as well as decreased exercise, both of which can lead to weight gain and/or difficulty losing weight.
It is controversial as to whether high insulin levels increase body weight. Although there is no concrete evidence, Dr Futterweit believes that high insulin levels play a role in weight gain because he sees a strong correlation between degree of insulin resistance and degree of obesity. Dr Samuel Thatcher, author of Polycystic Ovary Syndrome: The Hidden Epidemic, also believes that excess insulin can contribute to weight gain. In his book he explains that insulin not only promotes storage of fat and glycogen but also retards the breakdown of fat (lipolysis) and glycogen (gluconeogenesis). This has an effect of conserving energy and can lead to weight gain.
Other experts, including Dr Reaven, disagree. His studies do not show evidence that insulin resistance leads to obesity. He believes that if insulin is not working properly (insulin resistance), then glucose cannot be deposited into cells. If anything, weight loss, not weight gain, would occur. (8)
Whatever the reason for the increased prevalence of obesity, experts believe that weight loss is the first line of defense in the treatment of PCOS. (5) Studies show that losing 5% to 10% of weight is associated with decreased androgen levels, frequent improvement in menstrual regularity and skin appearance, and decreased hyperinsulinemia. (1) Insulin resistance is reduced within a few days after instituting a hypocaloric diet, even before much weight loss has occurred. (9)
As nutrition educators, we know that losing weight and keeping it off is a difficult task. In my experience, it is even more difficult for the woman with PCOS, whether due to the insulin resistance, carbohydrate cravings, emotional eating, or other factors. It is common to see a woman with PCOS struggling to lose even a few pounds. It is important that we be patient and supportive in our counseling sessions and focus on setting small goals. Remind the patient with PCOS that losing 5% to 10% of her body weight will most likely bring about a decrease in her symptoms.
Exercise plays a very important role in improving insulin sensitivity in skeletal muscle and fat tissue, thereby reducing insulin levels. Studies on patients who exercise demonstrate that muscle contractions accelerate transportation of glucose into the cells. (10) This factor lasts for several days after the exercise. However, the exercise must be performed on a regular basis; otherwise, the favorable effects are quickly lost. (7) It appears that both resistance training and aerobic exercise will decrease insulin resistance. (11,12) Exercise can decrease insulin resistance even in the absence of weight loss. (8) Aside from increasing insulin sensitivity, other health benefits of regular exercise include lowering blood pressure, lowering triglyceride levels, increasing HDL levels, lowering fasting blood glucose levels, and decreasing stress. In addition, exercise burns calories and preserves and/or build lean mass, which aids in weight loss as well as increases the chances for keeping off the weight.
Despite the obvious benefits of exercise, the majority of people do not exercise enough to positively affect their health. It is likely that women with PCOS who are overweight exercise even less due to associated physical discomforts or embarrassment from their weight or other symptoms. Rochelle Rice, founder of In Fitness and In Health in New York City, specializes in fitness for women who are overweight. She believes that too often there is a mentality among the overweight that exercise has to be intense and/or occur in a gym to provide benefits. This attitude keeps many women who are overweight from exercising. Instead, Rochelle recommends the focus be placed on helping the overweight women increase her overall movement and finding a physical activity that she finds enjoyable, such as walking, bowling, social dancing, or pool exercises, instead of forcing her to conform to an “ideal” program. The nutrition educator must be aware of the barriers to exercise for the women who is overweight and be creative in helping her to find an activity that she will be comfortable with.
In summary, exercise is key in helping to increase insulin sensitivity and promote weight loss. The ideal fitness program is one that includes both a resistance and an aerobic component. However, the priority is helping the women with PCOS to find a physical activity that she enjoys, and most important, one to which she will adhere.
Weight loss is vital if obesity is present. What is not agreed upon is the composition of the diet. Is the reduction of calories the only consideration, or is the nutrient distribution of the diet important as well? There have not, as yet, been many studies on diet and PCOS. Most of the studies done have been on diet and insulin resistance. It does appear that insulin sensitivity can be influenced by diet. Because the majority of women with PCOS are insulin resistant it is logical to recommend a diet that improves insulin sensitivity in addition to promoting weight loss. The lipid profile of the patient should also play a role in deciding the nutrient composition of the diet.
The typical low-fat high-carbohydrate diet may not be the best choice for an insulin-resistant woman with PCOS. High intakes of carbohydrate, especially refined carbohydrate, will cause the body to secrete more insulin to maintain glucose homeostasis. The increased production of insulin will only worsen the existing condition of hyperinsulinemia. Because hyperinsulinemia is believed to be at the root of the symptoms in PCOS, a more appropriate diet would be one that does not cause excess production of insulin.
As discussed, the majority of women with PCOS have elevated triglycerides and low HDL levels. The increased secretion of insulin in response to a low-fat high-carbohydrate diet will exacerbate the dyslipidemia. (13) High levels of insulin cause the liver to increase production of very low-density lipoproteins (VLDL), which will increase triglyceride levels. High triglyceride levels are associated with decreased HDL levels. In addition to raising triglycerides and lowering HDL levels in some individuals, high-carbohydrate/low-fat diets have been proved to increase the number of small dense LDL particles, another risk factor for heart disease.
Saturated fat and trans fats can increase risk of heart disease by raising LDL cholesterol. Because women with PCOS are believed to be at an increased risk of heart disease, it is recommended that saturated and trans fats be limited in the diet. As mentioned, it is not recommended to replace saturated fat with carbohydrates because this will only increase insulin levels and worsen the dyslipidemia. Aside from the effect on LDL cholesterol, some studies have demonstrated that saturated and trans fats exacerbate insulin resistance. (14-16)
Overall Recommendations on Macronutrients. It is generally agreed upon that a woman with PCOS who is insulin resistant should substitute unsaturated fat for saturated and trans fats and avoid very low-fat/high-carbohydrate diets. However, not all experts agree on the exact macronutrient breakdown of the diet.
Dr Reaven recommends a diet that is 45% carbohydrate, 40% fat (5% to 10% of calories from saturated fat), and 15% protein in his book Syndrome X: Overcoming the Silent Killer That Can Give You a Heart Attack. His research reveals that this is the ideal diet to decrease insulin resistance. However, he also believes that weight loss and exercise take priority over diet composition. The American Heart Association (AHA) generally recommends a diet with less than 30% fat. However, the 2000 AHA Dietary Guidelines also state that there may be some benefits for patients who are insulin resistant to follow a diet that reduces saturated fat while increasing the intake of unsaturated fat rather than carbohydrates, as long as an ideal body weight is attained and maintained. (17)
Brenda Bryan, RD, LDN, who works with Dr Samuel Thatcher, specializes in counseling women with PCOS. Her approach is not necessarily a low-carbohydrate diet but a moderate-carbohydrate diet based on the US Department of Agriculture (USDA) food group pyramid that emphasizes lower glycemic carbohydrates, whole grains, fruits, and vegetables. She also encourages lean protein foods at meals, along with “heart-healthy” fat to lower the glycemic index and promote satiety. She works with women who are overweight and reports having success in weight loss because she has a moderate and realistic approach to which her patients can better adhere.
Role of the Nutrition Counselor
The role of the nutrition counselor is three-fold–to educate the woman on PCOS, including the role of insulin resistance as well as the potential long-term complications; to assist her in planning meals and snacks that can help decrease food cravings and promote weight loss; and finally, to provide a support system and open ear for her frustrations.
Education is important for women with PCOS. The majority of women whom I counsel have never received a detailed education on what PCOS actually is. They also need to understand the potential long-term health risks associated with PCOS and learn how their food choices can affect these risks. They are empowered once they realize that they may be able to improve their symptoms through weight loss, exercise, and a low glycemic index diet.
Many women with PCOS have a lifelong history of dieting and have distorted views of what comprises a healthy diet. It is common to find women who are fat phobic and base their diets on carbohydrates–usually “on-the-run” refined carbohydrates. These women must be educated about the potential hazards of very low-fat high-carbohydrate diets increasing insulin levels. The nutrition counselor should educate them on the effects of various foods on blood glucose and how to select lower glycemic index carbohydrates. On the opposite side of the spectrum, other women have heard “carbs make you fat” and have an aversion to eating carbohydrates. Their diets tend to be high in protein and fat, especially saturated fats. Again, education is needed to improve the nutritional content of the diet.
MEAL PLANNING FOR WEIGHT LOSS AND TO DECREASE CRAVINGS
It is important that the nutrition counselor tailor the diet to the individual as opposed to adopting a “one-size-fits-all” approach. The patient’s lifestyle, food preferences, preparation abilities, snack habits, cravings, etc, should all be considered when developing a dietary plan. Hillary Wright, MEd, RD, specializes in working with women with PCOS at the Harvard-Vanguard Medical Associates in Boston, Mass. She finds that most of her patients experience frequent carbohydrate cravings as well as mood swings in response to high intakes of carbohydrates, especially refined carbohydrates. She finds that adding protein and fat to meals, substituting whole grains for refined grains, and increasing the overall fiber content of the diet, usually leads to decreased carbohydrate cravings as well as improved mood. This will increase the chances of adherence to the meal plan and weight loss. Hillary also stresses the importance of smaller more frequent meals to increase energy levels and keep hunger in check.
It is important to help women find meals and snacks that are satisfying both physically and psychologically. When working with patients, stress the importance of listening to how her body feels after eating various meals or individual foods. For example, does a nonfat yogurt or an apple as a snack satisfy her or does it set off cravings? If it is not satisfying, she may be better off having a higher fat snack, such as natural peanut butter on whole grain crackers. Is a bowl of whole-grain cereal topped with berries satisfying for breakfast? If it triggers more hunger or cravings, then a higher fat, lower carbohydrate breakfast, such as an omelet made with 1 egg, 3 egg whites, and an ounce of soy cheese with a slice of whole grain toast may be a better alternative. Nutrition educators must be open-minded to the idea that a low-fat high-carbohydrate diet may not be the best approach for a woman with PCOS. Tailoring the diet to the individual and having the patient listen to her body are the two helpful steps toward finding an eating plan that will be successful in promoting weight loss.
PCOS can have a significant effect on a woman’s well-being, self-esteem, and body image. A woman may feel stressed regarding her weight, hair, and skin changes. Dr Kevin Kelly is a psychiatrist who practices in New York City and works with women with PCOS. He sees additional areas of stress that evolve around infertility issues, distortion of sexual activity, and disturbance of the female identity. Many women with PCOS are also dealing with the physiologic effects of hormones and medications that can include irritability, tearfulness, and mood swings.
Many women with PCOS have had their symptoms ignored for years and have never received the proper diagnosis or treatment. Many patients have intense anger at having had their symptoms ignored for so many years. Chances are that a woman was admonished by her physician because of her difficulties in losing weight and told just to be more disciplined and eat less. The patient with PCOS can benefit the most from a nutrition counselor who provides a supportive environment during the counseling sessions and takes the time to listen to her feelings. It can be helpful to address stress and emotional eating in the sessions. The patient can also be referred to a local support group or chat room (http://www.PCcSupport.org or http://www.obgyn.net/PCOS/PCOS.asp). Women with PCOS often find comfort knowing that they are not alone. The nutrition counselor should be aware that depression and eating disorders are common in PCOS. If it is deemed appropriate, these patients should be referred to a psychotherapist.
Lifestyle Recommendations for Polycystic Ovary Syndrome
In summary, lifestyle recommendations for PCOS include the following:
* No one diet works for everyone. Each diet must be tailored to suit the individual
* The first priority is weight loss. Even losing 5% to 10% of body weight will help decrease symptoms of PCOS. This is much more important than the macronutrient composition of the diet.
* Exercise helps decrease insulin resistance, promote weight loss, and improve self-esteem as well as overall health. The ideal program includes an aerobic and resistance training component.
* Identify problem behaviors and work on making permanent behavior changes. Make small changes one at a time. Food records can help identify problem behaviors.
* Do not think of this as a short-term diet but rather a healthy eating plan to be followed for the long-term.
* A hypocaloric diet must be adhered to if weight loss is to occur. All calories count–whether from protein, fat, or carbohydrate. This must be emphasized because it is common to see women who feel they can eat unlimited amounts of protein and fat-rich foods as long as they keep their carbohydrate intake low.
* Consume a balanced diet that contains carbohydrates, fats, and proteins. Although the exact macronutrient composition of the diet has yet to be agreed upon, it has been suggested that the diet contain 45% to 50% carbohydrates, 15% to 20% protein, and up to 35% fat (5% to 10% of calories from saturated fat).
* Select lower glycemic index carbohydrates over high glycemic index or refined carbohydrates. For example, select whole-grain breads and cereals over refined breads and cereals and select fruit over fruit juice.
* Adding fat and protein to meals can help increase satiety value, control carbohydrate cravings, and lower the glycemic response of the meal. For example, even though the caloric content is similar, a breakfast consisting of an egg substitute (or egg whites) with 1 oz of low-fat cheese and 2 slices of whole-grain toast may be a better choice than a 4 oz bagel with all fruit spread.
* Limit saturated fats (ie, butter, whole milk dairy, meats, poultry) and trans fats (ie, stick margarine, fried foods, and many prepared foods such a cookies and cakes) because these fats may increase risk of heart disease by elevating LDL cholesterol. Substitute unsaturated fats (ie, olive oil and other vegetable oils, nuts and nut butters) for saturated and trans fats.
* Include omega 3 fats, a polyunsaturated fat found in fatty fish, canola oil, leafy greens, and walnuts, in the diet to decrease risk of heart disease.
* Suggested vitamin/mineral supplements: calcium 1000-1500 mg (if the woman is unable to consume enough calcium from the diet) and multivitamin with minerals at Recommended Dietary Allowance levels.
* Avoid those foods that trigger cravings or buy these foods in individual sized portions (ie, sorbet pops versus pints of sorbet)
* Avoid smoking because it increases risk of heart disease and lung cancer as well as exacerbates insulin resistance.
In conclusion, diet, exercise, and weight loss have been proved to play major roles in the treatment of PCOS. The ideal diet for PCOS is one that promotes weight loss and then weight maintenance. The exact macronutrient breakdown of the diet is not agreed upon. However, the majority of women with PCOS may benefit from a low glycemic index diet. This diet, along with weight loss and exercise, may lower insulin levels, thereby leading to a decrease in androgens and an improvement of symptoms. In addition, a low glycemic diet can improve the dyslipidemia associated with PCOS. Finally, many women report decreased carbohydrate cravings and increased energy levels on a low glycemic index diet. However, it is important that each patient be assessed on an individual basis and be provided with a total care plan that fits her specific needs.
Recommended Web Sites
* http://www.healthology.com/focus_index.asp?b=healthology (articles and Web casts on PCOS)
Factors that increase insulin resistance:
* Physical inactivity
* High carbohydrate intake
* Very low-fat diets
* Certain medications
Benefits of exercise:
* Increases insulin sensitivity
* Decreases blood pressure
* Raises HDL cholesterol
* Burns calories
* Increases lean mass
* Aids in stress management
* Lowers fasting glucose
* Decreases triglycerides
(1.) Futterweit W. Polycystic ovary syndrome: what you should know. Available at: http://www.heahhology.com/focus_article. asp?f=women&c=women_PCOS. Accessed October 25, 2001.
(2.) Thatcher S. Polycystic Ovarian Syndrome: The Hidden Epidemic. Indianapolis, Ind: Perspective Press; 2000.
(3.) Legro R. Family, fat and fitness: an update on the PCOS families study. Presented at: Seminar PCOSupport Conference; June 7-9, 2001; King of Prussia, Pa.
(4.) Perloe M. Polycystic ovary syndrome … treatment with insulin lowering medications. Paper presented at: Seminar PCOSupport Conference; June 7-9, 2001; King of Prussia, Pa.
(5.) Nestler JE. Insulin resistance effects on sex hormones and ovulation in the polycystic ovary syndrome. In: Reaven, GM, Laws A, eds. Insulin Resistance: The Metabolic Syndrome Syndrome. Totowa, NJ: Humana Press; 1999:347-365.
(6.) Kidson W. Polycystic ovary syndrome: a new direction in treatment. Med J Aust. 1998;537-540.
(7.) Corbald A. Insulin resistance in PCOS. Paper presented at: Seminar PCOSupport International Conference; June 1-3, 2000; San Diego.
(8.) Jacobson M, ed. Syndrome X: the risks of high insulin. Center Sci Publ Inter Nutr Action Health Lett. 2000;27(2):3-8.
(9.) American Diabetes Association. Consensus development conference of insulin resistance. Diabetes Care. 1997;21(2):310.
(10.) Gasser GA. An exercise physiologist’s perspective. The role of insulin resistance in diabetes treatment. On Cutting Edge: Diabetes Care Educ Newslett. 1997;18(6):25.
(11.) Fluckey JD, Hickey MS, Brambrink JK, Hart KK, Alexander K, Craig BW. Effects of resistance training of glucose tolerance in normal and glucose-intolerant subjects. J Appl Physiol. 1994;77:1087-1092.
(12.) Wallace MB, Mills BD, Browning CL. Effects of cross training on markers of insulin resistance/hyperinsulinemia. Med Sci Sports Exer. 1997;29:1170-1175.
(13.) Coulston AM. Insulin resistance: its role in health and disease and implications for management. Hershey Foods Corp Top Nutr. 1997;6:1-10.
(14.) Riccardo G, Rivellese A. Dietary treatment of the metabolic syndrome–the optimal diet. Br J Nutr. 2000;83(suppl 1):S143-S148.
(15.) Lovejoy JC. Dietary fatty acids and insulin resistance. Curr Atheroscler Rep. 1999;1(3):215-220.
(16.) Vessby B, Unsitupa M, Hermansen K, et al. Substituting dietary saturated fat for monounsaturated fat impairs insulin sensitivity in healthy men and women: The KANWU Study. Diabetologia. 2001;44(3):312-319.
(17.) Nutrition Committee of the American Heart Association, AHA Dietary Guidelines. Circulation. 2000;102:2284-2299.
From The New York Presbyterian Hospital.
Corresponding author: Martha McKittrick, RD, CDN, CDE, 436 E 69th St, New York, NY 10021 (e-mail: email@example.com).
Martha McKittrick, RD, CDN, CDE, specializes in weight control, hyperlipidemia, polycystic ovarian syndrome, and diabetes. She has been on staff at The New York Presbyterian Hospital for the past 17 years. She also counsels clients privately and is a consultant to physicians, corporations, and health clubs. She is on the medical advisory board for the Polycystic Ovarian Syndrome Association (PCOSA) and is on the editorial advisory board for PCOS Pavilion of OBGYN.NET. She has lectured on diet and PCOS at the PCOSA conferences in San Diego, New York, and Philadelphia.
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