The Basics of the Fertility Diet

Infertility is an issue that impacts many women and families who are trying to conceive, and for some, making dietary changes is part of their overall plan to support and improve their ability to conceive. The Fertility Diet is intended to increase a woman’s chance of ovulation through changes in eating patterns and physical activity.

Though there are many reasons why someone might struggle to conceive, the Fertility Diet is meant to address ovulatory infertility specifically—a condition in which a woman does not ovulate and therefore is unable to conceive. Ovulatory dysfunction can occur when a woman has irregular, infrequent (defined as fewer than nine per year) menstrual periods, or when she does not ovulate at all. Normally, one ovary in an adult woman of childbearing age releases one egg each month, which may be fertilized if it comes into contact with sperm. While there are different kinds of ovulatory dysfunction, women struggling with infertility often experience a dysfunction in which their ovaries do not release one egg each month.

So, if you or someone you know is struggling with infertility, is the Fertility Diet right for you?

Guidelines for the Fertility Diet

The Fertility Diet is based on a book published by Harvard professors in the late 2000s that primarily explains data from the Nurses’ Health Study (a prospective cohort study) on the impact of food intake and, to a lesser degree, other lifestyle variables on infertility due to ovulatory dysfunction.

The Fertility Diet outlines ten key diet and exercise changes women can make to increase their chances of ovulation, outlined below:

• Avoid trans fats.
• Use more unsaturated vegetable oils, such as olive oil and canola oil.
• Eat more plant-based protein, like beans and nuts, and less animal protein.
• Choose whole grains and high-fiber foods when possible.
• Consume milk fat every day.
• Take a multivitamin with folic acid.
• Get plenty of iron from fruits, vegetables, beans, and supplements, but less from red meat.
• Be mindful of what you drink. Drink water most of the time.
• Aim for a healthy weight.
• Start a daily exercise plan.

The Fertility Diet and Your Health

A dietary pattern consistent with the recommendations put forth by the U.S. Dietary Guidelines for Americans (DGA) has been associated with improved fertility in women and higher semen quality in men. The DGA emphasize the importance of consuming whole grains, monounsaturated or polyunsaturated oils, vegetables, fruits, and fish—which you’ll notice are similar to the recommendations put forth by the guidelines for the Fertility Diet.

But what does research say about the Fertility Diet? The Nurses’ Health Study, published by a team of Harvard researchers in 2007, found that women with ovulatory infertility who followed the prescribed eating pattern outlined for the Fertility Diet had a 66% lower risk of ovulatory infertility and a 27% reduced risk of infertility from other causes than women who didn’t follow the diet closely. (See this resource about the difference between absolute and relative risk.)

Moreover, a recent narrative review summarizing current scientific evidence on associations between dietary intake and fertility concurs that diets high in unsaturated fats, whole grains, vegetables, and fish have been associated with improved fertility in both women and men. While current evidence on the role of consuming dairy, alcohol, and caffeine is inconsistent, high consumption of saturated fats and sugar have been associated with poorer fertility outcomes in women and men.

Limitations

The Nurses’ Health Study is a prospective cohort study. In a prospective cohort study, subjects are identified based on exposure status prior to the development of the disease or condition of interest, and the outcome is measured over time. Prospective studies cannot determine a causal relationship between the exposure and a health outcome. In contrast, randomized controlled trials can provide evidence for a causal relationship. While randomized controlled trials have examined the connection between certain foods or supplements and fertility, no randomized controlled trials have been conducted on the guidelines put forth by those in the Fertility Diet book.

The Fertility Diet: The Bottom Line

While it may seem like a unique dietary approach at first glance, the Fertility Diet recommendations are similar to the DGA. In other words, a healthy and balanced diet and regular physical activity in general may, in addition to improving overall well-being, increase one’s chances of ovulating, thereby increasing the chance of pregnancy. However, it’s important to remember that this diet is based on the results of a prospective cohort study, which does not prove cause and effect. Additionally—and we cannot overstate the nuance here—this diet is specifically meant to address ovulatory dysfunction, but there are many reasons people may struggle to conceive. If you are experiencing difficulty with your fertility, be sure to consult your general practitioner or OBGYN about a referral to a board-certified fertility doctor who can help you explore options for treatment.