Q My sister has had little luck in getting pregnant. Is there any truth to the book "Fertility Diet?" — F.G., Winterville

A Dr. Walt Willett and his colleagues are sharing another insight from their long standing Nurse's Health Study in this new book. I am all for promoting healthy weight and healthy diets to women of child-bearing age and this book may be right for some women. Paige Clark, a third year medical student, accepted the challenge of answering your question. By the way, I often ask Dr. Janice Daugherty from ECU's Department of Family Medicine to ensure the medical aspects of my column are correct. She made some helpful suggestions. But, here is what Paige Clark learned.

A new book, "Fertility Diet" written by Harvard researchers Jorge Chavarro, Walter Willett, and Patrick Skerrett, claims that a diet rich in high fiber, low-glycemic carbohydrates, monounsaturated fats, and vegetable protein increases fertility outcomes in women with ovulatory disorder infertility. Without going into all the details, let me state that only about 1 in 12 women who have difficulty getting pregnant experience this type of infertility. As part of the Nurses' Health Study, the investigators looked at the behaviors of 17,544 women with no history of infertility as they tried to become pregnant over an 8-year period. The women provided a dietary history and information on physical activity, height and weight. Dr. Willett and colleagues developed a "fertility diet" based on foods that appeared to decrease the infertility rates observed in these women. They were probably considering that up to 1 in 10 women has some irregularity in ovulation associated with a condition called Polycystic Ovarian Syndrome or PCOS. Women with PCOS are more likely to have irregular menstrual periods, be overweight and develop Type 2 diabetes. The Fertility Diet is quite similar to the dietary recommendations for patients with insulin resistance or Type 2 diabetes.

The authors recommend eating "slow carbs". They suggest eating slowly digested carbohydrates that are rich in dietary fiber like fruit, vegetables, brown rice, pasta, and dark bread rather than easily digested carbohydrates like white bread, potatoes, and sugared sodas to increase a woman's fertility chances. These researchers argue that the easily digested carbohydrates have a higher glycemic load, and raise the body's insulin level too high, which will inevitably disrupt the hormone balance needed for ovulation and reproduction. We certainly know that women who are overweight have more difficulty getting pregnant than their normal weight counterparts. And, typically women who are overweight drink more sodas and eat more simple carbohydrates.

As far as fat intake is concerned, the authors recommend balancing your fat intake. Their study found that women who had as little as 4 grams of trans fat per day in the place of more healthful unsaturated fat were found to have a decreased fertility rate. This is equal to the amount found in 2 tablespoons of margarine, 1 medium order of fast food french fries, or 1 doughnut. Choosing to use monounsaturated fats such as canola or olive oil in place of highly saturated fats is a better choice and might improve your chances of becoming pregnant. Read the Nutrition Facts on foods to avoid trans fats. But remember, it is not possible to avoid all trans fats, as some occur naturally in food.

The book suggests that having a higher intake of vegetable protein, found in beans and nuts, and a lower intake of animal protein seemed to be another way women could improve fertility chances. The authors suggested adding one serving a day of beans, peas, nuts, tofu or soybeans. A daily serving of red meat, chicken, or turkey was associated with a 1/3 increase in ovulatory infertility.

Dr. Willett is well known for his "Eat, Drink and Be Healthy" book. Perhaps the biggest deviation from other diets developed by Dr. Willett is the recommendation about dairy intake. The most fascinating finding of the study was that 1 to 2 servings a day of whole milk and foods made from whole milk (full-fat yogurt, cottage cheese, and ice-cream) may offer some protection against ovulatory infertility.

The reason the authors gave was that removing fat from milk changes the hormone content of the milk and therefore may interfere with normal ovulation cycles. Of course, the authors recommend only consuming whole milk while trying to get pregnant, or weight gain will become an issue. Otherwise they recommend only one serving a day of skimmed milk, cheese or yogurt, or a calcium supplement.

Now you may be thinking, "Will this diet help me get pregnant?" The authors realize that this diet is not a cure for infertility. They feel that it may enhance the chances of becoming pregnant, while also decreasing the risk of heart disease, stroke and diabetes. However, one should not rely solely on this method to become pregnant.

If you are hoping to conceive, be aware that there are certain things women who could become pregnant need to do. For example, be sure to get at least 800 mg of folic acid each day to decrease the likelihood of neural tube defects.

The March of Dimes and other health organizations suggest the easiest way to do this is to take a daily multiple vitamin.

Make an appointment for pre-conceptual counseling with your family doctor. He or she will advise you on the steps you can take to improve your chances of a successful pregnancy and a healthy baby, including recommendations for the best diet based on your individual needs.

Professor Kathy Kolasa, a registered dietitian and Ph.D., works with the Family Medicine Center, Brody School of Medicine at ECU. Contact her at kolasaka@ecu.edu, or C/O The Daily Reflector, P.O. Box 1967, Greenville, NC 27835.