Background: Saturated fat consumption has been correlated with some cancers and cardiovascular disease. Yet, whether saturated fat is correlated with abnormal sperm parameters needs more research.

Objective: To determine the impact of dietary fat on semen parameters among 701 young Danish men without azoospermia.

Design/Methods: This was a cross-sectional study of men recruited from their military fitness exam (2008 to 2010). Three-month recall-validated 136-item food frequency questionnaire, single semen sample, and physical examination were conducted for each participant. Median age was 19 years and median body mass index (BMI) was 22.5.

Results: Men with a high intake of saturated fat had lower total sperm counts. Men in the highest quartile of saturated fat intake had a 38% significantly lower concentration and a 41% significantly lower total sperm count compared to men in the lowest quartile. There were no other significant correlations found between semen parameters and other forms of dietary fat intake.

Conclusions: Diet may be a partial explanation for the reported greater abnormalities observed in sperm counts from other studies of the general population. Reducing the intake of saturated fat may improve reproductive and overall health parameters.

Reviewer’s Comments: This is part of a continuing series of studies that suggest you are what you consume in your diet regarding certain areas of health and – to some extent – fertility. Second, this is a cross-sectional study, whether it is a semen sample or dietary questionnaire is not level 1 evidence. In fact, the correlation between food frequency questionnaires and reality is still far apart. I do not remember what I ate yesterday, let alone months ago. Yet, the beauty of a large questionnaire and this study is that these snapshots might reveal a hidden general pattern or overall behavior that can provide some answers. I found it interesting that a higher percentage of men with a very low BMI were more likely to consume more saturated fat (seems counterintuitive, right?). Yet, men consuming more saturated fat were slightly more likely to smoke, drink more alcohol, report a sexually transmitted disease, consume more overall calories, eat more omega-6 fatty acids, and probably had less muscle mass. And, although the authors did adjust for most of these parameters in their study – which they believe makes the theory of saturated fat being a marker of unhealthy overall behavior less likely – I disagree (>30% of the saturated fat was coming from cheese and dairy products). There is a pattern of behavior to suggest a less healthy lifestyle in those who consume more saturated fat, which is similar to what has been found in many prostate cancer studies and cardiovascular reviews.(Reviewer–Mark Moyad, MD, MPH).