What is the success rate of using diet to get pregnant?
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. In addition, according to Chavarro, "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."
There are many factors affecting fertility. "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," says Philip E. Chenette, M.D., a fertility expert in San Francisco.
What foods and behaviors should we try?
Chavarro's recommendations from his book The Fertility Diet, McGraw-Hill, 2007 are:
- Avoid trans-fats, the artery-clogging fats in many commercial products and fast foods.
- Use more unsaturated vegetable oils, such as olive oil, 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 unrefined carbohydrates rather than highly refined carbohydrates that quickly boost blood sugar and insulin.
- Drink a glass of whole milk or eat a dish of full-fat yogurt every day.
- Take a multivitamin with 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 in moderation and 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 quite lean, don't overdo it).
How does an improved diet impact fertility?
According to Chavarro, most of the dietary factors that improve fertility impact "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 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.
Eating high-quality protein also appears to be important, according to Pak H. Chung, M.D., of Cornell University, primarily because gametes are essentially proteins.
What should you NOT 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 such as shark and 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.
And according to Eve Feinberg, M.D., a fertility expert in Illinois, caffeine 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."
What about what the male eats?
"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, what about all those who become pregnant while they are eating poorly or are overweight?
"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," says Chenette.
What about multivitamins?
Most over-the-counter multivitamins are fine. "The only thing I would make sure of is that it has at least 400mcg of folic acid and 40mg of iron," 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?
It's vital. "The greatest improvement in fertility with high-impact aerobic activities is for those patients who have ovulatory dysfunction," says Feinberg.
However, be cautious. "Excessive exercise can be associated with the hypothalamic type of anovulation or 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.
Join the Discussion: Do diet and exercise really affect fertility?
Charles Stuart Platkin is an Active Expert , nutrition and public health advocate, author of the best seller Breaking the Pattern (Plume, 2005), Breaking the FAT Pattern (Plume, 2006) and Lighten Up (Penguin USA/Razorbill, 2006) and founder of Integrated Wellness Solutions. Sign up for The Diet Detective newsletter free at www.dietdetective.com.