Exercise and Fertility (4 of 4): Harvard Study on Diet and Fertility

Key Takeaways:

  • Experts agree that when planning an exercise regimen to optimize one’s fertility, men and women should take into account the specific effects of their diets.

  • Studies have shown that Vitamin B12, Folic acid, and Omega-3 fatty acids have positive effects on fertility, whereas diets rich in red and processed meats, sweets, and sweetened beverages have a negative impact on fertility.

  • It is difficult to know exactly what to eat for optimal fertility, but it is important to maintain a healthy and balanced diet.


 

One primary reason why people exercise, particularly as the body slows down due to the process of aging, is to lose or maintain weight. Experts generally agree that paying attention to both exercise and diet patterns is vital for achieving a target weight, but that sticking to sound nutrition habits proves far more important than putting in those extra miles or reps.

In fact, says Angela Fitch, associate director of the Weight Center at Massachusetts General Hospital, “The only way you’re going to lose weight is to be more mindful of your calories, because we are notoriously poor at estimating how many calories we consume.”

As a result, when planning an exercise regimen to optimize one’s fertility, men and women should take into account the specific effects of their diets.

New Harvard study analyzes connections

Intrigued by attention-grabbing headlines on the subject, researchers from the Harvard T.C. Chan School of Public Health and Harvard Medical School recently set out to discover possible links between fertility and diet.

They published a review of past studies in the April 2018 edition of the American Journal of Obstetrics and Gynecology, noting that publications in this area had increased significantly over the last 10 or so years – a trend that has resulted “in the identification of a few clear patterns”.

Among the chief findings, the researchers determined that women who try to become pregnant without assisted reproductive technologies such as IVF can benefit from ingesting the following nutrients and vitamins:

·       Vitamin B12

·       Folic acid

·       Healthy diets, such as the Mediterranean diet

·       Omega-3 fatty acids

At the same time, though, the researchers discovered that vitamin D, antioxidants, caffeine, soy, dairy products, and alcohol seemed to have very little if any effect on fertility. Negative effects were detected in diets including trans fats as well as diets “rich in red and processed meats, potatoes, sweets, and sweetened beverages”.

For men, researchers found that studies covering their dietary habits determined that semen quality generally improves with adherence to similarly healthy habits as described for women, though the opposite proves true for diets high in trans or saturated fats. While caffeine and alcohol appeared to have negligible effects, the researchers noted, “Importantly, semen quality is not a perfect predictor of fertility, and most studies did not actually examine the impact of paternal diet on the rate of successful pregnancies”.

Unanswered questions remain

The Harvard researchers were unable to come up with satisfactory answers to some basic questions regarding the connection between diet and fertility, including the optimal amount of servings of dietary omega-3 fatty acids; which groups of people would benefit most or least from a diet plan aimed at boosting fertility; and, the ideal amount of B12 or folic acid.

Researchers also need to direct more attention to results of other studies, three of which were published in May 2018. One, published in the journal Epidemiology, concluded that women and men who consumed sugar-sweetened beverages experienced lower fertility, though drinking fruit juice and diet soda had no impact.

Another, published in the journal Human Reproduction, found that women who ate high quantities of fast food and not much fruit needed longer periods of time to conceive than did those with healthier diets.

And a third, published in The Journal of Clinical Endocrinology & Metabolism indicates that couples who consumed greater amounts of seafood got pregnant sooner than those who rarely ate seafood. Also, most pregnant women tend to eat much less than the recommended 2 to 3 weekly servings of low-mercury fish, such as shrimp, scallops, and salmon.

Taking the optimal approach

With all of that information, it’s still difficult to know for certain what, exactly, to eat for optimal fertility, other than to maintain a healthy diet overall and to consult a physician for helpful recommendations, including so-called “preconception” information.

It’s also wise to heed the conclusions penned by Robert H. Shmerling, MD, Faculty Editor, and Alison Shmerling, MD, MPH, Contributor, Harvard Health Publishing: “[J]ust in case it’s not obvious, don’t rely on research regarding diet and fertility to prevent pregnancy. An unhealthy diet and avoiding supplemental vitamins or omega-3 fatty acids is not a form of birth control”.

In the end, proactively storing your assets before and after embarking on a diet regimen may provide the best defense against changes to your eating routines.