A mother's diet and nutrition play an important role in the gestation of a healthy baby. A growing unborn child relies on its mother for vitamins, minerals, and energy, and the mother needs nutritious food to remain strong and healthy throughout pregnancy.
But what about fertility and nutrition? The American Society for Reproductive Medicine (ASRM) takes a skeptical view of the relationship between diet and fertility, saying that "there is little evidence that dietary variations such as vegetarian diets, low-fat diets, vitamin-enriched diets, antioxidants, or herbal remedies improve fertility."
While there are no guarantees that any dietary choices can make a difference, there is a growing body of scientific evidence to suggest that there may be a relationship between nutrition and fertility outcomes.
The Nurses' Health Studies
Much of what's known today about women's fertility and nutrition comes from a pair of large-scale studies of nurses in the United States and Canada. The Nurses' Health Studies (I and II) surveyed women about their health habits. The findings were published in the book The Fertility Diet (Chavarro & Willett, eds. Harvard University Press, 2009).
Many of the findings accord with recommendations for general health. Favorable fertility outcomes were associated with:
- Eating less animal protein (such as meat) and more protein from vegetable sources like nuts and legumes (beans and lentils).
- Avoiding "trans fats" found in processed foods (such as hydrogenated or partially hydrogenated vegetable oils).
- Doing physical activity
- Having a healthy body weight – a woman’s ability to ovulate is heavily impacted by her body weight. Being both overweight and underweight can impact ovulation. Women with extremely high or low body fat and weight may stop ovulating and menstruating. In addition, a researcher at the ASRM's 2013 annual conference presented evidence that if the ratio of waist size to hip size increases by 1 unit, there's the chance of conception dropping by 30 percent. She also observed a relationship between body weight and polycystic ovary syndrome (PCOS). Every increase of 1 unit of BMI corresponds to a 9 percent increase in PCOS, she said.
Surprisingly, researchers in the the Nurses' Health Study observed a correlation between drinking whole milk or eating full-fat yogurt at least once a day and better ovulatory fertility. While they found a link, it doesn't necessary mean those foods improved ovulatory fertility. It's also not a habit one would want to keep up long term.
While none of these studies definitively prove cause-and-effect relationship, and the findings should be taken with a grain of salt, there have been studies that suggest:
- Eating a Mediterranean-style diet, high in vegetables and fish and low in meats and snack foods, can improve chances of conception.
- Eating more omega-3 fatty acids before conception can improve embryo structure.
- Overweight women trying to get pregnant may be more likely to conceive and have a live birth if they lose weight in a healthy, gradual way.
What not to eat
And on the negative side:
- Drinking soda (carbonated drinks) of any kind may have a negative impact on women's fertility.
- ASRM notes that drinking more than five cups of coffee a day (or having the equivalent caffeine) has been associated with lower fertility. Even moderate amounts of caffeine could have a negative impact on fertility.
- Though the link between alcohol and fertility has not been clearly established, some studies suggest that even moderate amounts of alcohol could adversely affect fertility.
- Going on a very low-calorie diet to lose weight right before or around the time of IVF may decrease the chances of success.
- Higher concentrations of bisphenol-A (BPA) in women's urine was associated with poorer fertility outcomes. BPA is a chemical found in some plastics, such as some food containers and packaging materials, including cans. Another study, presented at the ASRM annual meeting in 2013, found no link between BPA in women and fertility outcomes. However, the researchers did find that BPA in male partners was associated with a 20 percent decrease in reproductive ability. Perhaps more alarmingly, a third study found that women with the highest concentrations of BPA in their blood (the top 25 percent) were at significantly higher risk of miscarriage.
- ASRM also cautions that mercury in seafood can negatively impact fertility.
- Women with unexplained miscarriages and repeated IVF failures may want to get tested to make sure they don't have undiagnosed celiac disease. If they do, a strict gluten-free diet may help their fertility.
- A very small study presented at the 2013 ASRM annual meeting found evidence that cinnamon might help regulate menstrual cycles. But only eight women actually received the cinnamon supplement, so further study is needed. Cinnamon can also increase the risk of kidney stones.
Updated August 2014