Diet and Lifestyle Management of PCOS By Hillary M. Wright, MEd, RD, LDN

Body: 

Diet and Lifestyle Management of Polycystic Ovary Syndrome: A Natural Approach to Healing a Woman's Health and Hormones
By Hillary M. Wright, MEd, RD, LDN, Author of The PCOS Diet Plan: A Natural Approach to Health for Women with Polycystic Ovary Syndrome (Ten Speed/Celestial Arts, 2010)
     

Some women have it all - excess facial hair; acne; thinning hair on the crown of the head; extra "belly fat" around the middle, instead of the butt and thighs; high blood pressure; low HDL or good cholesterol with high triglycerides (fats) in the blood; and irregular or completely absent menstrual periods.  For others, the symptoms are more subtle, limited to spotty periods, and a tendency to feel "edgy" when they go too long without eating.  But one thing these women may have in common is polycystic ovary syndrome, or PCOS, a female hormonal disorder that is known to be primary cause of infertility due to ovulation problems, but also places women with the condition at greater risk of a number of life-threatening health problems. 
  
It is estimated that PCOS affects up to 10% of all women during their reproductive years.  This figure appears to be rising with the obesity epidemic as excess weight tends to worsen PCOS.  Research also suggests that up to 30% of women have some of the symptoms of the disorder without meeting all the criteria for diagnosis (generally requires either irregular or absent periods, and signs of elevated androgens, or male-type hormones).  And with the dramatic increase in childhood obesity, which often leads to earlier onset menstruation, PCOS is already starting to show up in younger girls.  That means more years to live with the damaging health consequences of PCOS.  
 
For many women, the threat to fertility is understandably most upsetting, but equally concerning is that PCOS is a major risk factor for type 2 diabetes.  Diabetes is exploding in our population - type 2 diabetes has increased 40% in the last 10 years alone - and undiagnosed diabetes is seven times more likely in women with PCOS compared to similar age women without the condition.  In fact, without intervention, upwards of 50% of women with PCOS will develop full-blown diabetes or impaired glucose tolerance (pre-diabetes) by age 40.  Heart disease continues to be the number one killer of both women and men in the United States, and women with PCOS have four to seven times the risk of heart attack than women of the same age without PCOS. With women having children later in life, the number of women requiring fertility treatment is also on the rise, and the hormonal changes seen in PCOS stand to significantly contribute to this trend.  PCOS also increases the risk of gestational diabetes, and some research suggests that women with PCOS are three times more likely to miscarry than women without the disorder.

 

What Causes PCOS?

PCOS is a genetic condition, and much of what contributes to it is still unknown.  Research suggests that  a common underlying problem in at least 75% of cases of PCOS is a condition insulin resistance.  Scientists and health professionals know a lot about insulin resistance because, in its most advanced form, it's what causes type 2 diabetes.  Insulin is a hormone produced by the pancreas that is responsible for escorting glucose out of the blood and into the cells after you eat or drink carbohydrates.  Under normal conditions, insulin secretion is proportionate to carbohydrate intake - the more carbohydrate you eat, the more glucose is released into your blood, and the more insulin you secrete to clear it.  In insulin resistance, the cells resist insulin's cell-opening action, stimulating the pancreas to secrete additional insulin in an effort to force glucose into the cells.  Over time, this excess demand for insulin may reduce the pancreas' ability to produce insulin, ultimately leading to diabetes.  It's these higher circulating levels of insulin that are believed to have a toxic effect on the ovaries by interfering with the exquisite hormonal balance needed to nurture eggs to maturity and trigger ovulation. 

Diet and Lifestyle Factors Key to Managing PCOS.
Despite all the scary statistics about PCOS, not all the news is bad.  As a genetic condition, PCOS can't be cured, but it can be controlled.  Fortunately, insulin resistance  responds strongly to weight loss, exercise, a healthful diet, and medications (like Metformin), when necessary. Research tells us that losing as little as 5 - 7% of your weight can improve fertility and help prevent diabetes.

For most women with PCOS, the critical nutrition-related issues include weight loss; prevention of diabetes and heart disease; and emotional support around the disordered eating that is not uncommon in women with the condition (many report serious "carb-cravings" and problems with binge-eating when they get over-hungry).   Nutrition therapies targeting the underlying insulin resistance through a moderately carbohydrate-restricted diet that limits sweets and added sugars in favor of unprocessed carbohydrates, like whole grains, whole fruits (instead of juice), and low fat or non-fat dairy, show the most promise.  These high-quality carbs should also be distributed over smaller meals and snacks to reduce the post-meal glucose/insulin response.  Pairing carbohydrates with some lean protein and a little heart-healthy fats helps further slow the release of glucose into the blood, and enhances the feeling of fullness from a meal or snack (for example, snacking on a few whole grain crackers with reduced fat cheese).  Less circulating insulin produces less interference with reproductive hormones, and less strain on pancreatic function.  This diet therapy, paired with exercise (which naturally sensitizes cells to the action of insulin), is the most natural means of normalizing reproductive hormones, improving fertility and preventing diabetes. 

In my experience counseling hundreds of women with PCOS, the key to empowering them to manage their health  is helping them understand this insulin-diet-exercise connection, and how lifestyle choices may either improve, or worsen, their health and fertility.   It is estimated that 60% or more of women with PCOS are also overweight or obese, so for most women weight loss is the primary goal.  Fortunately, the same strategies that can help manage insulin resistance should also encourage weight loss, and promote overall good health. 

 

How Do We Know Diet Makes a Difference? 
For overweight or obese women with PCOS, we know that weight loss, however it is achieved, is the most powerful means of improving fertility and preventing diabetes.  But emerging research suggests where your calories are coming from may affect your success or failure in achieving a pregnancy. Let's take a look at where current research is pointing:

 

A 2007 study from the University of California-Davis of 28 women with PCOS looked at the relationship between nutrients and hormones known to be clinically important in PCOS. The women ate their usual diet and were then told to drink either 75 grams of glucose (sugar) or 75 grams of whey protein in liquid form. Blood levels of several hormones were tested in the five hours following the drink. Results showed significantly higher blood glucose and insulin levels in the hours after the glucose drink. Two-thirds of the patients with PCOS had hypoglycemia (low blood sugar) after drinking the glucose drink, and also experienced greater increases in their cortisol and DHEA levels (another hormone often elevated in PCOS). Cortisol is a stress hormone that can contribute to obesity by increasing hunger and cravings for sweets and fatty foods, and encouraging the deposit of fat in the abdomen. It also stimulates the release of glucose from the liver - raising blood glucose levels - and aggravates insulin resistance. Even more interestingly, the glucose drink suppressed levels of ghrelin, often referred to as "the hunger hormone," for shorter periods of time than the protein drink, meaning it took longer for the subjects to feel hungry after the protein drink. Although this study used protein and glucose drinks as opposed to foods high in protein and carbs, these findings support the potential benefit of including more protein in the diet. 

 

 A 2009 study from the University of California-Davis compared the effects of protein versus simple sugar on weight loss, body composition and blood levels of fasting glucose, insulin, and cholesterol levels in 24 women with PCOS. Researchers first decreased the women's diets by 700 calories overall and then added back a 250 calorie supplement of either whey protein or simple sugar, so the overall calorie reduction was 450 calories less per day. The results? The protein supplemented subjects lost more weight and more body fat, had larger decreases in total cholesterol, and higher levels of healthy HDL, or "good cholesterol." This study also provides support for the potential benefits of including more protein and limiting added sugars. 

 

A 2005 weight loss study from the University of Colorado looked at the calorie composition question a little differently, not by studying women with PCOS specifically, but rather obese non-diabetic women who had been determined to be either insulin-sensitive or insulin resistant. Again, this was a fairly small study of only 21 women ages 23 to 53. In both the insulin sensitive and insulin resistant groups, women were put on either a high carb/low fat diet or a low carb/high fat diet; both were low in calories to promote weight loss. Interestingly, in this study the type of diet that resulted in more weight loss depended on whether the woman showed signs of insulin resistance: over the 16 weeks of the study the insulin sensitive women lost more weight on the high carb diet, and the insulin resistant women lost more weight on the low carb diet. Both groups lost an average of about 13.5 pounds. Given that most women with PCOS are assumed to have some degree of insulin resistance, this study supports moderately cutting carbohydrate intake.   
What about the effect of diet and exercise on fertility?

 

In 2003, a study from the University of Milan in Italy of 33 overweight women with PCOS who either didn't ovulate or ovulated infrequently found that a 1200 calorie restricted diet and exercise had a significant effect on their rates of ovulation. Twenty-five of the 33 patients lost at least 5% of their weight.  Regular menstrual cycles returned in 72% of the patients who complied with the diet, and of the women who lost at least 5% of their weight, 40% subsequently became pregnant. It should be noted that 1200 calorie diets are very restrictive, and a more gradual approach to weight loss is generally recommended prior to pregnancy. 

One very recent 2010 study of 96 overweight and obese Clomid-resistant women with PCOS that combined a 6 week lower calorie diet and exercise intervention with a cycle of Clomid therapy found that combining these interventions resulted in a significantly higher ovulation rate.   

These are some of the more recent studies on diet and PCOS, and, as you can see, most studies to this point have had fairly few study subjects. As such, the optimal dietary treatment for PCOS is not yet clear. Large scale studies could offer some important insights into the best diet for PCOS, but for now our best bet is to go where the research suggests, avoiding any extreme approaches that could inflict any potential harm (such as diets less than 40% carbohydrate). Studies so far strongly support that eating well and exercising regularly can make a major difference.   Weight loss via any approach will benefit PCOS, from both an overall health and fertility standpoint. Weight loss decreases insulin resistance, helps regulate reproductive hormones, and enhances fertility. It also improves blood cholesterol levels, lowering "bad" LDL cholesterol and boosting "good" HDL cholesterol. Some research supports the usefulness of a higher protein diet (as opposed to high carb) because of its ability to slow carbohydrate digestion and increase the feeling of fullness after a meal or snack.  Most importantly, a moderate protein, carbohydrate-distributed diet is in no way extreme or unhealthy to follow long term, and takes into account what we know benefits overall health.

Hillary Wright is the author of The PCOS Diet Plan: A Natural Approach to Health for Women with Polycystic Ovary Syndrome (Ten Speed/Celestial Arts, 2010)

 

Hillary Wright is a registered and licensed dietitian with over 20 years experience counseling clients on diet and lifestyle change. She holds a Bachelor Degree in Human Nutrition from the University of Massachusetts at Amherst, and a Master of Education in Health Education from Boston University.  Hillary is the Director of Nutrition Counseling for the Domar Center for Mind/Body Health at Boston IVF, one of the nation's oldest and most successful fertility clinics, where she specializes in nutrition and women's health issues, and is the author of "The PCOS Diet Plan: A Natural Approach to Health for Women with Polycystic Ovary Syndrome" (Ten Speed/Random House Press). Hillary is also a nutrition writer, speaker and consultant to industry and health-related organizations. Hillary can be reached at www.pcosdiet.com. 

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