October 2, 2014

expert reaction to alcohol consumption and sperm and semen quality

A paper on the effect of alcohol consumption and aspects of fertility has been published in the BMJ Open. The researchers found that sperm levels and quality were particularly reduced in men consuming above the recommended guidelines for intake of alcohol.

Dr Allan Pacey, Senior Lecturer in Andrology, University of Sheffield, said:

“Men and their partners who are trying to start a family are understandably concerned to know if aspects of their lifestyle are detrimental to sperm production and male fertility. However, with regard to alcohol consumption and semen quality the data has been conflicting, with some reports suggesting evidence of harm and others showing no effect.  As far as I am aware, we also don’t currently know by what biological mechanism alcohol consumption could reduce semen quality, so more research is needed.

“The UK 2013 NICE Fertility guideline (CG156) suggest that doctors should discuss alcohol consumption with men who are concerned about their fertility and suggests that: “Men should be informed that alcohol consumption within the Department of Health’s recommendations of 3 to 4 units per day for men is unlikely to affect their semen quality” (recommendation 18). This equates to 21 to 28 units per week. Therefore, the conclusions of the paper by Professor Jensen are broadly consistent with this recommendation: the relationship between alcohol consumption and poor semen quality was most apparent in men who drank 25 or more units in the week prior to semen analysis, which is right in the middle of DH’s recommendations if drunk steadily over the week rather than in one go.

“The men in this study were healthy volunteers with no history of infertility and so an important question is whether the same relationship is also true for men who are struggling to conceive. In 2012 I co-authored a paper that investigated the alcohol consumption of almost 2,500 men in infertile partnerships (Povey et al., 2012 Human Reproduction 29: 2799 – 2806) and this found no relationship with alcohol consumption and semen quality, even in the heaviest of drinkers. Taken together, our 2012 study and the new study by Jensen suggest that for all men (infertile or not) drinking alcohol within recommended guidelines probably has little effect on semen quality. Therefore, there is no need for men who want to start a family to become t-total, or for doctors to recommend that.

“However, binge drinking is quite different, and it is possible that consuming more than the recommended daily allowance of alcohol (>5 units) as a one off, or on a regular basis, could affect semen quality differently compared to men who spread their alcohol consumption more evenly over a week. The 2013 NICE Fertility guidelines recommend “Men should be informed that excessive alcohol intake is detrimental to semen quality” (recommendation 19) and in my opinion this would seem sensible advice. However, Professor Jensen’s paper found no strong evidence that binge drinking on its own was linked to poor semen quality. In my opinion, this should not be seen as a green light for men to have guilt-free benders once in a while as Jensen points out that men who drank heavily or who were more frequent binge drinkers, were also more likely to be smokers, drink more caffeine and were more likely to have had a sexually transmitted infection or fever. And we know all of these can decrease semen quality in one way or another regardless of how much alcohol is consumed.”

Prof Darren Griffin, Professor of Genetics, University of Kent, said:

“It is always difficult to draw firm conclusions from this data given the many variables involved and 1221 males is not an especially large sample size. It comes as no surprise that excessive alcohol intake might have an adverse effect on semen quality and ultimately fertility. However the extent to which this data means that men in any of the groups are any more or less likely to father children (which is really where the real concern lies) is a far more complicated question. The authors do some clever statistical transformations to arrive at their conclusions however, notably, some of the least favourable parameters appear, at least in this data set, to be in men that abstain from alcohol completely. What I’m not seeing in the paper is a massive dip in the factors measured associated with alcohol intake however it should be noted that “binge drinking” is defined as 5 units (2-2.5 pints) in one session.  Perhaps greater effects would be seen in the heaviest of drinkers i.e. those who drink a lot and regularly. Maintaining a good standard of health, including responsible drinking, extends to our reproductive health and we don’t really know whether the heavier drinkers were also those with less healthy lifestyle overall. I would like to see more studies in this area.”

Prof Chris Barratt, Professor of Reproductive Medicine, University of Dundee, said:

“This is an important study as the experiment used a relatively large number of men, standardised semen assessments and quality questionnaire.  As mentioned in the discussion there are conflicting data on semen quality and alcohol consumption but the strengths of this study are a big plus, however this study doesn’t prove that drinking alcohol causes the observed differences in sperm and semen.

“I think the main message of this paper is clear – high levels of alcohol intake do appear to be associated with changes in sperm and semen that may affect fertility, but it is interesting to note that men who didn’t drink any alcohol at all also had reduced semen quality – this was not commented on in the paper but needs further research.”

Dr Jackson Kirkman-Brown, Reader in Human Reproductive Science, University of Birmingham, said:

“The authors present an interesting study, with probably the most reliable findings to date on alcohol and sperm quality, due to the number of healthy young men involved and survey details taken. A real strength is that these were unselected young men turning up for mandatory medicals so they were not there to ask a ‘fertility’ question. The paper reinforces the message that a healthy lifestyle is important for your sperm quality wherever it starts out and particularly highlights for the first time that one-off binge drinking can have serious effects on sperm that will take longer than your hangover to recover from. This paper finds obvious changes in the ability of sperm to swim and their external appearance – it is worth noting that there are likely to be more severe changes in the genetic quality of the sperm which cannot be observed by the simple tests undertaken by these authors, meaning the overall effect of excessive alcohol consumption is likely to be greater rather than less than they have observed.”

Prof Sheena Lewis, Professor of Reproductive Medicine, Queens University Belfast, said:

“This is a large well-designed study of 1221 healthy young men who were just undergoing a routine semen analysis as part of a mens’ health check prior to military service.  Unlike previous studies where men may have underestimated their typical weekly intake, this study asked recruits to report their alcohol intake daily.

“The results are compelling. Men who drank around 5 units a week had reduced sperm counts and impaired sperm quality. This alcohol damage was even more pronounced in men who drank more than 25 units a week.

“If this is the effect that alcohol can have on these young men, men trying for a family may be wise to reduce their alcohol intake before and during their fertility treatment.”

Dr David Miller, Reader in Molecular Andrology, University of Leeds, said:

“Excessive drinking  is an increasing worry for health professionals, particularly those concerned with the rising incidence of liver disease in young people. However, this study suggests that it’s not only the liver that we should be worried about.

“The study’s authors asked a large group of young male Danish conscripts, more than 1200, about their drinking habits prior to obtaining  semen samples from them and  found that the more alcohol these men claimed to have consumed, the poorer their fertility appeared, measured  in terms of sperm count, concentration and appearance.

“The authors freely admit that it is hard to dissociate the suggested cause (excessive alcohol consumption) from the effects of lifestyle choices that may  coincidentally include excessive drinking but may also lead to lower fertility even among those who do not drink excessively. Although the authors present no evidence that these observed effects will necessarily lead to lower fecundity in the men concerned, studies aimed at assessing the impact of alcohol consumption on reproductive success or otherwise must surely follow.”

‘Habitual alcohol consumption associated with reduced semen quality and changes in reproductive hormones; a cross-sectional study among 1221 young Danish men’ by Tina Kold Jensen et al. published in BMJ Open on Thursday 2 October 2014.  

Declared interests

None declared