Carb Intake, Sperm Count Association Explored

At last, an answer to the question, "Why can't the Chinese reproduce?"

Rice is carbohydrate.

As carbohydrate intake and dietary glycemic load increase, sperm concentration decreases, according to research presented here at the American Society for Reproductive Medicine (ASRM) 68th Annual Meeting.

Researchers analyzed data on 189 men 18 to 22 years of age who were enrolled in the Rochester Young Men's Study, conducted at the University of Rochester in New York, in 2009 and 2010.

The men's diets were assessed with a validated food frequency questionnaire, and semen samples were analyzed for sperm concentration, motility, and morphology.

The participants (82% white) had a mean body mass index (BMI) of 25.3 kg/m² and were highly physically active, spending an average of 11 hours per week on moderate to vigorous physical activity.

On average, about 50% of the men's diets was made up of carbohydrates.

After adjustment for factors such as total energy intake, age, abstinence time, BMI, smoking status, and the intake of protein, caffeine, and alcohol, the steady decline in sperm concentration was consistent with increasing quartiles of total carbohydrate intake (P for trend = .08): 49 million/mL (95% confidence interval [CI], 31 to 74) in the lowest quartile, followed by 47 million/mL (95% CI, 32 to 70), 37 million/mL (95% CI, 25 to 55), and 35 million/mL (95% CI, 23 to 51) in the highest quartile.

There was also an association between dietary glycemic load, which reflects the amount and quality of carbohydrates in the diet, and reduced sperm concentration (P for trend = .04). Adjusted sperm concentrations, from lowest to highest glycemic load, were 59 million/mL (95% CI, 39 to 91), 37 million/mL (95% CI, 26 to 55), 43 million/mL (95% CI, 29 to 62), and 32 million/mL (95% CI, 22 to 48).

Sperm motility was not associated with carbohydrate intake or with dietary glycemic load, and neither was morphology.

According to lead author Jorge E. Chavarro, MD, from the Department of Nutrition at Harvard Medical School in Boston, Massachusetts, data on the nature of dietary influences on sperm concentration, in general, are lacking.

Little is known about how diet and other modifiable lifestyle factors affect human fertility, but "it has been shown very consistently that being overweight or obese is strongly related to poor semen quality," he told Medscape Medical News.

"We also know that many of the systemic effects of obesity, such as chronic low-grade inflammation and insulin resistance, can be elicited by the composition of diet, independent of body weight," Dr. Chavarro explained. "With this in mind, we wanted to know if one aspect of diet, namely carbohydrate intake, was related to semen quality," he said.

Stupid.