Men planning to conceive may want to reconsider high-dose antioxidant supplements, according to a new study from Texas A&M University. Researchers found that regularly consuming high doses of antioxidants like N-acetyl-L-cysteine (NAC) and selenium can negatively influence sperm DNA and potentially lead to craniofacial differences in offspring, even without impacting the father’s overall health.
Antioxidants are widely marketed for their potential health benefits, including preventing chronic diseases, treating conditions like COPD and dementia, and slowing the aging process. They are also frequently used in treatments for male infertility. However, this research, published in Frontiers in Cell and Developmental Biology, suggests a more nuanced picture.
The study, led by Dr. Michael Golding of Texas A&M’s College of Veterinary Medicine and Biomedical Sciences, involved exposing male mice to NAC and selenium – two commonly used antioxidants – for six weeks. The researchers then observed differences in the skull and facial shape of the offspring, despite the fathers showing no apparent health changes. This finding challenges the assumption that antioxidants are universally beneficial, particularly when taken in high doses.
“We know alcohol causes oxidative stress and we were looking to push back on it by adding a supplement known to lower oxidative stress,” explains Dr. Golding. “When we realized that offspring born to males that had only been given NAC were displaying skull and facial differences, it was a surprise because this molecule is universally thought to be good.”
The unexpected results prompted the team to consider the concept of balance. “If you’re taking a multivitamin to ensure that you’re in balance, but if the thing that you’re taking to ensure you’re in balance is unbalanced (the dose of antioxidants is too high), then you’re not doing a good thing,” Dr. Golding stated.
The researchers noted a striking similarity between the observed craniofacial abnormalities in the mice offspring and those seen in fetal alcohol syndrome, specifically closer-set eyes and smaller skulls. This connection suggests a potential link between high antioxidant levels and disruptions in central nervous system development.
“There’s a very commonly accepted truism in pediatric medicine that the face mirrors the brain, because the brain and the face form at the same time,” Dr. Golding explained. “When your face migrates (during gestation), it’s using cues from your brain to know where to go, and if the two things are not aligned, there’s either a delay or some kind of abnormality in brain development.” He further noted that facial abnormalities can often indicate underlying neurological issues, such as problems with impulse control, epilepsy, and other developmental concerns.
While further research is needed to determine whether these findings translate to humans, the study raises important questions about the widespread use of high-dose antioxidant supplements. The team is continuing to investigate this “unexplored frontier” to better understand the potential risks, and benefits.
The study also draws a parallel to the effects of excessive exercise. Just as too much strenuous activity can be detrimental to endurance athletes, high doses of antioxidants may impair reproductive fitness. “Sperm health is another performance metric; it’s just not one that we think about in everyday life,” Dr. Golding said. “If you’re taking a high dose antioxidant, you could be diminishing your reproductive fitness and part of the journey toward the bad outcome is going to be the effects on the offspring.”
The researchers emphasize the importance of balance when it comes to nutritional supplementation. While antioxidants play a vital role in maintaining health, exceeding recommended daily amounts – particularly when there isn’t a specific medical need – may have unintended consequences. “Think of yourself as a plant—if you stick your plant out in the sun too long, it’s going to get dehydrated. If you overwater your plant, it gets root rot. But if you have the right balance of sunshine and water, that’s when growth occurs. Health is in that domain,” Dr. Golding said.
He advises caution regarding supplements containing extremely high levels of antioxidants, including NAC, a common ingredient in multivitamins. “If your vitamins are providing 1,000% of the recommended daily amount, you should be cautious,” he said. “If you stick to the 100% range, then you should be OK.”
This research underscores the need for a more informed approach to antioxidant supplementation, particularly for men considering starting a family. While antioxidants are not inherently harmful, moderation and a balanced intake appear to be key to optimizing both individual health and the well-being of future generations.
