A popular amino acid supplement touted for focus and brain health may come with a hidden cost for men: higher blood levels of tyrosine were linked to a shorter lifespan, according to new research published in Aging-US.
The research
Scientists from the University of Hong Kong and the University of Georgia analyzed health data from more than 270,000 participants in the UK Biobank, a large long-term health database. They looked at two amino acids: phenylalanine and tyrosine. Both are found in protein-rich foods and supplements marketed for cognitive performance.
Using two statistical methods—standard observational analysis and a genetic technique called Mendelian randomization—the team aimed to determine whether amino acid levels could actually cause differences in lifespan, rather than just being correlated.
Initially, both amino acids seemed linked to higher death rates. But after adjusting for other factors, only tyrosine remained consistently associated with lifespan, and only in men. The genetic analysis estimated that elevated tyrosine levels could shorten a man's life by nearly one year. Women showed no such effect, a finding that may help explain why men generally live shorter lives than women.
Notably, phenylalanine showed no association with lifespan after accounting for tyrosine, suggesting that tyrosine itself is the key factor.
Why it matters
Tyrosine is a building block for neurotransmitters like dopamine and norepinephrine, which influence mood, attention, and motivation. That's why it's a common ingredient in focus and energy supplements. But its potential impact on longevity adds a new cautionary note.
While the exact mechanism is unknown, researchers suggest that tyrosine might affect insulin resistance or stress hormone pathways, both of which are tied to aging. More studies are needed to establish causality and understand the biology.
What you can do
If you're taking a tyrosine supplement, discuss it with your doctor, especially if you're male. Keep in mind that dietary sources—like meat, dairy, and legumes—provide tyrosine as part of a balanced diet, and supplements are not typically necessary for most people.
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Source: ScienceDaily Mind & Brain
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