Does what you eat affect your fertility?
Q. Does what you eat affect your fertility?
A. Scientists know more about how diet affects the fertility of livestock animals than they know about how it affects humans; relatively few studies have examined whether what we eat affects our chances of conceiving. So far, the evidence supports eating for overall good health.
Jorge Chavarro, a researcher at the Harvard School of Public Health and coauthor of “The Fertility Diet,’’ led the largest study to date that addresses the question, following more than 18,000 women in the Nurses Health Study who were trying to conceive. The study considered whether those who experienced ovulatory infertility — a common cause of infertility in women — had different diets than those who successfully conceived.
“It so happened that the majority of dietary factors that appear to be beneficial for fertility are also factors that are known to be heart healthy,’’ Chavarro says. They include eating slowly digested carbohydrates like whole grains, avoiding trans fats, and eating more proteins from plants than from animals.
The only evidence that contradicted advice for general health was that consuming a moderate amount of full-fat dairy products was associated with successful conception, while consuming skim and low-fat milk was associated with infertility. Chavarro cautions that the intake is modest — a glass of whole milk per day, or a cup of ice cream per week, and anyone adding full-fat dairy to their diet should compensate for the additional calories.
A small study in the Netherlands, published in March, found that couples undergoing fertility treatments were more likely to conceive if the woman followed a Mediterranean diet, which emphasizes vegetables, vegetable oils, and fish. Chavarro says that getting enough iron and folic acid also seems to be important for fertility. Women can get adequate levels of both by taking a daily prenatal vitamin. Less is known about diet and male infertility, but a handful of studies have found that folic acid is also important for sperm quality in men.
The clearest way that diet can affect fertility is through body weight. Women who are extremely lean, or are overweight or obese, have more difficulty conceiving, and overweight men seem to be less fertile as well.