Popular brain supplement linked to shorter lifespan in men

A brain-boosting nutrient may sharpen your mind but knock years off your life.Research suggests the popular supplement ingredient, widely touted for improving focus and cognitive performance, may have a surprising downside when it comes to longevity.Scientists found that men with higher levels of the substance in their blood tended to have shorter lifespans — but women don’t appear to pay the same price.In the study, scientists from the University of Hong Kong and the University of Georgia analyzed health and genetic information from more than 270,000 people in the UK Biobank. The researchers were focusing on two amino acids — phenylalanine and tyrosine — and whether they might play a role in aging.Both are essential building blocks for proteins, but tyrosine also helps the body make dopamine, adrenaline and other brain chemicals involved in mood, focus and stress response.Phenylalanine, meanwhile, is converted into tyrosine in the body.

Both amino acids occur naturally in protein-packed foods and are also commonly found in dietary supplements.To investigate whether the nutrients play a role in longevity, the researchers first looked at participants’ blood levels and compared them with their mortality and predicted lifespan.They then used a genetic testing method called Mendelian randomization, which involves looking at natural genetic differences between people to help determine whether one factor might actually cause another.The team found that men with more tyrosine in their blood appeared to have shorter lifespans — with elevated levels associated with nearly a year shaved off their lives.Women, however, didn’t appear to have the same link.

“Phenylalanine showed no association with lifespan in either men or women after controlling for tyrosine,” the study authors wrote.Researchers don’t yet fully understand why higher tyrosine levels might be linked to shorter lifespans in men, but they have a few ideas.One involves insulin resistance, a ...