Posts Tagged ‘sperm quality’

Modest Alcohol Consumption Lowers Semen Quality

Drinking modest amounts of alcohol may affect the sperm quality of young men, according to a new study.

“Young men should try to avoid habitual alcohol intake of more than 5 units weekly and especially more than 25 units weekly, which may be beneficial not only for their general health but their semen quality as well,” said Tina Kold Jensen, Professor of Research at the Department of Environmental Medicine, University of Southern Denmark, Copenhagen, Denmark.

One unit of alcohol was defined as the equivalent to 1 beer, 1 glass of wine, or 1 shot of alcohol.

“We also found that increasing alcohol consumption the week preceding the visit was associated with changes in reproductive hormones, especially a significant increase in serum free testosterone and reduction in sex hormone binding globulin,” Dr. Jensen said.

HEALTHY YOUNG MEN AND THEIR ALCOHOL

This appears to be the first study among healthy young men with detailed information on alcohol intake.

Dr. Jensen said, “Previous studies have not found adverse effects of low alcohol intake (more than 5 units per week), however, they only assessed average intake.

We assessed daily intake the week preceding the semen delivery.”

She added: “We think we found a strong association because we asked the men about intake last week and then extrapolated to a normal week.

We know that normal sperm take 3 months to mature.

Normal consumption is a better marker than just last week’s consumption.”

STUDY RESULTS

The cross-sectional, population-based study asked 1221 men to fill out a questionnaire on whether the previous week was a “normal” week of alcohol consumption and then studied the 553 who stated that it was.

These men, age 18 to 28 years, all had undergone a medical examination between 2008 and 2012 to assess their fitness for military service, which is compulsory in Denmark.

Sperm concentration, total sperm count, and percentage of spermatozoa with normal morphology were negatively associated with increasing habitual alcohol intake.

This association was observed in men reporting at least 5 units in a typical week but was most pronounced for men with a typical intake of more than 25 units per week.

Men who had a typical weekly intake of more than 40 units had a 33% reduction in sperm concentration compared with men who had an intake of 1 to 5 units per week.

Binge drinking was not independently associated with semen quality.

“We do not know how much of a direct effect on semen quality was due to the adverse effect of alcohol on spermatogenesis, but we adjusted for other lifestyle factors, such as smoking, diet, and exercise,” said Dr. Jensen.

“But it may be a certain lifestyle associated with alcohol intake that is harmful to semen quality.”

The researchers think that even moderate alcohol consumption could be a contributing factor in the low sperm counts reported among young men.

Whether semen quality is restored if alcohol intake is reduced remains to be seen, they stated.

The researchers reported their results in the October 2, 2014 issue of the British Medical Journal Open.

Obese, Overweight Men Have Inferior Semen

Men who are overweight or obese have lower sperm counts and lower ejaculate volumes, according to the results of the first study to make this association in men who were trying to conceive, but who did not have known infertility.

“Our study provides further data showing the link between being overweight and sperm quality,” said lead author Dr. Michael Eisenberg of Stanford University School of Medicine.

“Most prior studies examined infertile men only, while our study examines all men who were trying to conceive.

Moreover, we looked at both body mass index (BMI) as well as waist circumference to determine the relationship with sperm production.”

Dr. Eisenberg and colleagues examined data from the Longitudinal Investigation of Fertility and the Environment Study, a population-based, prospective cohort of more than 500 couples attempting to conceive in Texas and Michigan.

They analyzed data from 468 men, mean age 32, the majority of whom (82%) were overweight or obese.

More than half said they participated in physical activity less than once a week.

Fewer than 10% had a low sperm count.

The researchers reported their results online on December 4, 2013 in the journal Human Reproduction.

When the researchers examined semen parameters, they found that ejaculate volume declined with increasing BMI and waist circumference.

Similarly, the total sperm count showed a linear decline with waist circumference.

A man in the normal BMI range had an ejaculate volume of 3.3 mL, compared with 2.8 mL for men who were severely obese.

Men with the largest waists, more than 40 inches, had about 22% lower total sperm count compared with men who had waist measurements under 37 inches.

The percentage of men with abnormal volume, concentration, and total sperm increased with increasing body size.

There was no significant relationship seen between body size and other fertility factors, including semen concentration, motility, vitality, morphology, or DNA fragmentation index.

“Body size as measured by BMI or waist circumference is negatively associated with semen parameters, with little influence of physical activity,” Dr. Eisenberg noted.

The Heavier Man, The Lower the Sperm Count

The heavier the man, the higher the chances of a low sperm count, he suggested.

“I think bringing attention to another adverse outcome of obesity is important,” Dr. Eisenberg said.

“Men need to know that in addition to health aspects, obesity may also impair reproductive goals.”

It’s still unknown what a reduction in body weight does to the sperm counts of men starting with a low sperm count, Dr. Eisenberg noted.

“We don’t have a good answer at this point,” he said.

“However, we do know that weight loss helps overall health, so at a minimum we can expect a health benefit for an overweight man who loses weight.”

Dr. Eisenberg stated that primary care physicians need to “bring awareness to this relationship.

This may provide another motivation for men to change lifestyle habits, knowing that it can impact fertility.”

In addition, as men discuss plans for starting a family, this study can provide important information as to who may be at risk for impaired fertility, he noted.