Gentlemen, you may want to hold the bacon. A new study suggests that eating a high-fat diet may be associated with lower sperm quality.
The study, published online in the European journal Human Reproduction, found that men who ate diets higher in saturated fat had lower sperm counts and concentration than men who consumed less fat. But men who consumed more omega-3 fatty acids — healthy fats found in fish and plant oils — had better formed sperm.
Researchers looked at 99 American men in their mid-30s who were participating in an ongoing study on fertility and environment, at the Massachusetts General Hospital Fertility Center. From December 2006 to August 2010, the researchers questioned the men about their diet and analyzed their semen samples.
The men were divided into three groups based on their total fat intake. The men in highest third of fat consumption (at least 37% of their total calories) had a 43% lower sperm count and 38% lower sperm concentration than the men with the lowest fat intake.
Saturated fats appear to be the star culprit behind poor sperm quality in this study. Men who consumed the most saturated fat (at least 13% of their daily calories) had a 35% lower total sperm count and a 38% lower sperm concentration than the men consuming the lowest levels.
Men who ate the most omega-3 fatty acids, however, had more correctly formed sperm.
According to Dr. Richard Sharpe of the Medical Research Council’s Human Reproductive Sciences Unit at the University of Edinburgh, for normal functionality, sperm depend on their plasma membrane, which is mainly composed of fats. “It is therefore not unreasonable to imagine that the type of fats in the diet may affect sperm membrane fat composition which, in turn, may affect sperm function. To an extent, we are what we eat,” he said in an email statement. Dr. Sharpe is the deputy editor of Human Reproduction and is unaffiliated with the study.
“Diets containing higher amounts of omega-3 fat and lower amounts of saturated fat are associated with favorable semen quality parameters and may be beneficial to male reproductive health,” says study author Dr. Jill Attaman, assistant professor of obstetrics and gynecology at Dartmouth Medical School. “Although these findings need to be reproduced, adapting these nutritional modifications may not only be beneficial for reproductive health but for global general health as well. Given the impact infertility has worldwide, many men as well as couples may benefit from such lifestyle changes.”
The new study has its limits. For starters, the researchers acknowledge that the study sample was small and 71% of the participants were overweight or obese. Although previous research has associated obesity with poor sperm quality, the researchers were able to control for this factor. “We were able to isolate the independent effects of fat intake from those of obesity using statistical models,” said Dr. Attaman in a statement. “The frequency of overweight and obesity among men in this study does not differ much from that among men in the general population in the U.S.A.”
Since it is the first study reporting a relationship between dietary fat and semen quality, the study authors stress the need for further research.
But, men, there’s no shortage of health reasons to adopt a lower-fat diet now. “It is common sense to recommend that men adopt such a diet. If this should also improve their sperm concentration and quality, then it is icing on the cake,” said Dr. Sharpe.