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Young male gym users are largely unaware of the risks of their lifestyle on their fertility, a new study shows.

New results from a survey of 152 gym enthusiasts, published in Reproductive BioMedicine Online found that men were largely unaware of the risks to their fertility from aspects of gym lifestyle including protein supplements, which can contain high levels of estrogen, used by 79% of male respondents.

When questioned about their concern about fertility, more than half (52%) of male participants said that they had thought about their fertility before. However, only 14% of men who took part had considered how gym routines or supplement use might impact on fertility.

Further data shows that there was a significant difference in responses about whether the benefits of gym routines and supplements were more important to them than fertility, with 38% disagreeing and 28% agreeing. Female participants meanwhile were more aware of the impact of gym lifestyle on male fertility.

... there is a significant lack of awareness of male reproductive health in the young adult population we surveyed.

Dr Meurig Gallagher

Dr Meurig Gallagher from the University of Birmingham and lead author of the study said:

“Being healthy and having a healthy lifestyle is a good thing. In the context of male fertility, the concern is over the increasing use of protein supplements. The main concern is the high levels of the female hormone estrogen that comes from both whey and soy protein supplements. Too much female hormone can cause problems with the amount and quality of sperm that a man can produce. Many protein supplements that can be bought have been found to be contaminated by anabolic steroids, which can cause reduced sperm count, shrunken testicles, and erectile dysfunction amongst other things.

“Infertility is a problem of increasing concern, affecting 1 in 6 people worldwide according to the World Health Organisation. Globally, there is limited understanding of the fact that men contribute to half of these cases of infertility.

“The major finding from this study is that there is a significant lack of awareness of male reproductive health in the young adult population we surveyed. While people were aware of the problems associated with anabolic steroid use, very few understood that gym protein supplementation can have negative effects.

Not only a 'female issue'

Professor Jackson Kirkman-Brown from the University of Birmingham and author of the paper said:

“We found that men are genuinely curious about their fertility when prompted, but that they don’t think about it on their own – likely because societally people still think of fertility as a ‘female issue’ and (incorrectly) believe that men’s fertility doesn’t change throughout their lifetimes.”

“It’s important that people don’t see this as a reason not to be healthy or get exercise – but people should try and educate themselves about any form of supplementation they take, whether that is protein, vitamins or anything else.

"In general, most data would suggest it's better to eat unconcentrated natural food sources of protein, as these are also less likely to be contaminated at a high level with any environmental pollutants. For example, if you are eating a routine diet, roast chicken would be a good source of protein as opposed to a concentrated protein bar or shake.”