What would you consider the success rate of using diet to help you get pregnant?
According to Philip E. Chenette, M.D., a reproductive endocrinologist and fertility expert based in San Francisco, “Overall, the contribution of diet to fertility is about 10 percent for the average U.S. citizen. There are many factors affecting fertility: quality of the egg and sperm, #health of the uterus and fallopian tubes, frequency of intercourse and effectiveness of ovulation, to name a few. Diet influences some of these, particularly egg and sperm health and ovulation, but there are many other factors at work, such as prior injury or infection, age and its strong influence on egg number and quality, and anatomic abnormalities of the uterus and fallopian tubes — problems that cannot be addressed with diet. In some individuals, diet risk to fertility is much higher, such as high-intensity athletes, women with anorexia, and alcohol abusers.”
In fact, the Nurses’ Health study showed that those who did not follow a healthy diet were six times more likely to experience infertility related to ovulation than women who did. “You can never be younger than your chronological age. However, by maintaining bad habits, such as smoking, high-fat diets or lack of exercise, one can accelerate the aging process and may have a worse fertility potential than would be expected based on age alone,” says Eve Feinberg, M.D., a fertility expert in Illinois.
According to Chavarro, aside from a lower risk of experiencing infertility caused by ovulatory factors, “Following healthier dietary and lifestyle habits was also related to decreased odds of experiencing infertility due to other causes, such as endometriosis, although not as strongly as for ovulatory disorder infertility.”
What foods and behaviors should we be following?
Dr. Chavarro’s recommendations (from his book The Fertility Diet, McGraw-Hill, 2007) are:
- Avoid trans-fats, the artery-clogging fats found in many commercial products and fast foods.
- Use more unsaturated vegetable oils, such as olive and canola oils, and cut back on saturated fat from red meat and other sources.
- Eat more vegetable protein, like beans and nuts, and less animal protein.
- Choose whole grains and other sources of unrefined carbohydrates rather than highly refined carbohydrates that quickly boost blood sugar and insulin.
- Drink a glass of whole milk or have a small dish of ice cream or full-fat yogurt every day; temporarily trade in skim milk and low- or no-fat for full-fat dairy products.
- Take a multivitamin that contains folic acid and other B vitamins.
- Get plenty of iron from fruits, vegetables, beans and supplements (not from red meat).
- Drink coffee, tea and alcohol only in moderation — but skip sugared sodas.
- If you are overweight, lose 5 to 10 percent of your body weight.
- Start a daily exercise plan (if you are already lean, don’t overdo exercise).
How does an improved diet impact fertility?
According to Chavarro, most of the dietary factors that improve fertility advance “the body’s ability to respond to insulin, which in turn improves ovulatory function, either by reducing the amount of glucose in the bloodstream after a meal (e.g., favoring low-glycemic carbs), by improving the ability of muscles to respond to insulin (e.g., increasing physical activity) or even by affecting the expression levels of genes known to affect insulin sensitivity (e.g., avoiding trans-fats).”
Folic acid and iron are “both very important in DNA replication and in the maturation of the egg prior to ovulation, and folic acid may improve the response of the ovary to follicle-stimulating hormone,” adds Chavarro.
The only dietary factor relating to fertility for which Chavarro cannot provide a clear explanation is the positive effect of high-fat dairy. “The relation could be due to high-fat dairy products carrying over some of the pregnancy hormones of cows in enough quantities to influence reproductive function in people consuming them,” he says.
And according to Pak H. Chung, M.D., of the Center for Reproductive Medicine and Infertility, Weill Medical College of Cornell University, “Proteins are the most important entity in diet for fertility, as gametes are essentially proteins. I tell patients to pay attention to consuming high-quality proteins in their diet, such as dairy products, plant proteins, etc.”
What would you encourage women NOT to consume?
“Alcohol, because of its effects on folic acid; high-fat and trans-fat foods (because of effects on ovulation and long-term health); potentially toxic seafood (shark, tuna); raw dairy products (because of rare infectious diseases); and simple carbohydrates such as cakes and doughnuts (because they have no nutritional value and stimulate insulin),” says Chenette, the San Francisco fertility expert.
And according to Feinberg, caffeine intake has been associated with decreased uterine blood flow. “This, in turn, may prevent implantation of a developing embryo. Ideally, it is best to avoid caffeine in the pre-conception period. Additionally, there have been some studies linking high caffeine intake (over 300 milligrams a day) to increased risk of miscarriage and low birth-weight babies.”
What about what the male eats; does that have an impact?
“Men, capable of producing a million sperm per hour, have a huge fertility reserve. It is possible, with severe dietary indiscretion, to cause problems with sperm production, though this is unusual. There is data to indicate that antioxidants [glutathione and cryptoxanthin] are helpful for sperm production, but their effects are minimal,” says Chenette. The primary offender for male fertility is alcohol, he adds. “The ability of this non-nutritional carbohydrate to get into every cell in the body and interfere with folate metabolism, as well as the typical junk-food diet that accompanies its use, are negatives. It interferes with male erectile performance,” says Chenette.
If diet is so important to fertility, what about all those who become pregnant while they are eating poorly, are overweight, or are not exercising, and who have generally unhealthy habits?
“A young woman with healthy eggs can conceive and deliver a child in the face of a poor diet, since the egg has such resiliency. An older woman with marginal eggs must take advantage of every practical measure to optimize her egg quality. In cases of a severely poor diet, it is certainly possible, even in an otherwise healthy woman, to induce miscarriage, preterm labor, birth defects and fetal demise. Every obstetrician has seen this happen and can tell a story of an affected patient and pregnancy,” says Chenette.
What about multivitamins?
Most multivitamins available over the counter are fine. “The only thing I would make sure of is that the multivitamin has at least 400 mcg of folic acid and 40 mg of iron, as most prenatal multivitamins do,” says Chavarro. Supplementation with DHA (Docosahexaenoic acid — an essential fatty acid) may also be beneficial. “This is one area where it is important to note that more is not better. High doses of vitamins and minerals can be toxic,” says Feinberg.
How important is exercise on a scale of 1 (lowest importance) to 10 (highest importance)?
Exercise is a vital addition to fertility therapy. “The greatest improvement in fertility with exercise is for those patients who have ovulatory dysfunction as a primary diagnosis. In this population of patients, I would say exercise is a ‘10’ and would definitely recommend running, spinning or other high-impact aerobic activities that burn calories and aid in weight loss. For all others, I would say that exercise is a ‘7,’ a vital part of life in achieving health and wellness,” says Feinberg.
However, be cautious. “Excessive exercise can be associated with the hypothalamic type of anovulation [not ovulating]. Runners, for instance, have a lower tendency to have regular ovulation. I tell patients who ovulate on a regular basis not to intensify their exercise routine if they desire fertility,” adds Chung.
What are some other important factors that influence fertility?
Severe stress is clearly detrimental to fertility. “Stress has been associated with anovulation and irregular menses,” says Pak. In fact, studies of prisoners indicate poor fertility parameters under periods of stress. And studies of the earthquake survivors of Kobe, Japan, show poor fertility, particularly in those who suffered close family losses. “The best advice is to seek pregnancy with a healthy mind and body, to work to eliminate stress that prevents focus and decision-making with regard to the problems of fertility, and to work to optimize the relationship that will care for the pregnancy and baby after delivery. We encourage mind-body approaches, stress reduction, acupuncture and a holistic approach to optimizing your biologic health,” says Chenette.