Protein Supplements May Pose Male Infertility Risks

Most men are unaware of the possible risks of taking protein supplements to gain muscle, according to a study.

Although a male factor accounts for up to half of infertility cases, men's reproductive health is neglected by policies around the world. The lack of societal awareness and education surrounding men's infertility are among the key contributors to the ongoing male reproductive health crisis.

A new study published in Reproductive Biomedicine Online suggests that men may be unaware of possible infertility risks posed by certain sports and consumption of protein supplements.

The findings on these risks, however, remain conflicting, and more research is needed to better understand the effects of a gym lifestyle on male fertility.

Most men are unaware of the risks

The researchers surveyed 153 students at the University of Birmingham, most of whom were 18 to 25.

Male participants exercised six to nine hours a week on average, and 79% reported using or having used protein supplements primarily to gain muscle mass.

While more than half (52%) of the male participants said they had thought about their fertility before, only 14% reported previously thinking about the consequences of gym routines and supplementation on their fertility.

Most (76%) of male respondents said they would change their behavior if they knew it had a long-term impact on their fertility. Only 41% would change their routines if the impact was short-term.

What risks does the gym lifestyle pose?

Previous research has associated weightlifting, cycling, and physical strength exercises with reduced sperm quality. However, other studies indicated that cycling and weightlifting may positively affect male fertility and link physical inactivity with poorer sperm quality.

About 56% of gym-goers in the United States use dietary supplements as part of their gym routine, with protein powder being the most common.

There are concerns about high concentrations of the female hormone estrogen and its plant equivalent phytoestrogens/isoflavones in whey and soy protein supplements.

The evidence of their adverse effects on male infertility, however, is scarce. Meanwhile, studies suggest that phytoestrogen supplements may help reduce blood pressure, cholesterol levels, and inflammation and help control blood sugar.

A small 2019 study associated stopping protein supplementation with a 2.6-fold increase in sperm concentration in subfertile men. However, an earlier study suggested that the semen parameters in healthy adult males were not significantly altered after two months of eating a high or low soy isoflavone protein isolate diet.

Men should not be discouraged from exercising

The study does not prove that certain types of exercise and protein supplementation cause male infertility; it just shows that many men are unaware of possible risks.

The findings should not discourage men from engaging in physical activity, as it helps to reduce the risk of coronary heart disease and stroke, type 2 diabetes, several cancers, and early death in both men and women.

Moreover, exercising may help men to maintain a healthy body weight. Studies have associated obesity with a lower testosterone level, poorer sperm quality, and reduced fertility.

Adults need 150 minutes of moderate-intensity physical activity and two days of muscle-strengthening activity a week, according to the Physical Activity Guidelines for Americans.

The study authors call for educational awareness campaigns targeted at young, gym-going men to improve awareness that actions like smoking or protein supplement use can have long-term impacts on their fertility.