You (and your sperm) are what you eat

October 20, 2011Carole No Comments »

We’ve all heard the expression, “You are what you eat”, meaning that good dietary habits will positively influence how you look and feel overall. But did you expect that the food you eat might have an effect on your sperm? Two new studies presented at this week’s American Society for the Study of Reproduction (ASRM)’s annual meeting suggests just that. Audrey J. Gaskins, a doctoral student at the Harvard School of Public Health’s department of nutrition, and her colleagues queried 188 men between the ages of 18 and 22 about their dietary habits. The men’s questionnaire responses were used to categorize their diets as  either “Western”  or “Prudent”. Western diets were defined as high in red meat, refined carbs, sweets and energy drinks. Prudent diets were high in  fish, fruit, vegetables, legumes and whole grains. Semen analysis was performed to look at the men’s motility (sperm movement), concentration and morphology (the shape of sperm). This study showed that motility was negatively effected by the Western diet.  This finding persisted even when other confounding factors like body mas index and smoking were factored in. So if  you want Olympic swimming sperm, eat your legumes!

In my previous IVF program, we published a similar study looking at the effect of various lifestyle factors on sperm which included smoking and body mass index (BMI). We wanted to use a functional sperm assay (hyaluronan binding) as our measurement of sperm quality. Sperm bind to naturally occurring hyaluronan (a high molecular weight glycosaminoglycan) on the cells surrounding the freshly ovulated egg and this pre-fertilization cellular interaction is important to successful fertilization. Sperm acquire this ability to bind hyaluronan in the final stage of maturation and this binding ability is a characteristic of sperm that successfully fertilize eggs. This hyaluronan binding ability can be tested by challenging sperm to bind to glass slides pre-coated with hyaluronan. The higher percentage of sperm that have this binding ability in the ejaculate, the more likely the man is to be fertile. We used this slide test as an indicator of sperm quality. Interestingly, we found that both tobacco use and abnormally high body mass index were associated with  a tendency to perform more poorly in the binding test. Obesity has  been associated with reduced fertility in both men and women.

The second ASRM study looking at diet and sperm quality was presented by Dr. Jorge Chavarro, an assistant professor of nutrition and epidemiology at the Harvard School of Public Health. You may know Chavarro from his work analyzing the Nurses Study to examine the effects of lifestyle (including diet) on female fertility which he turned into a popular infertility book, The Fertility Diet. I blogged about his research in a previous post, “Fertility Diet: Can nutrition affect fertility?“. Chavarro’s study  of just under 100 men revealed that men who eat diets that contain a relatively high amount of trans fat had lower sperm concentration then men with diets lower in trans fat. Interestingly, the increased dietary trans fat resulted in increased trans fat found in their sperm and semen. His study found a negative effect of  trans-fat intake on sperm concentration but not on sperm motility or morphology.

Although both these sperm studies are small, the results are consistent with our general understanding that the food we eat affects how well the human body works. Why would we expect our reproductive organs and cells to be unaffected by dietary and lifestyle factors? If you need one more good reason to take good care of your physical self, protecting your fertility can be added to the list.

© 2011, Carole. All rights reserved.

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