The study, conducted by a research team from the University of Hong Kong, the University of Georgia, and published in the journal Aging, focused on the role of two amino acids, phenylalanine and tyrosine, in shaping human lifespan.
The results showed that high blood tyrosine levels were associated with a lower life expectancy specifically in men, indicating a different biological response between the sexes.
Phenylalanine and tyrosine are both essential components of metabolism and nerve signaling in the brain. They are naturally found in protein-rich foods such as meat, dairy, eggs, and legumes, and are also common in dietary supplements.
Tyrosine attracts particular scientific attention because the body uses it to produce neurotransmitters such as dopamine and norepinephrine, which support cognitive function, the body's stress response, and mood regulation. Therefore, tyrosine is often added to commercial products marketed to improve mental focus and stress tolerance.
To investigate the long-term effects of these amino acids, researchers analyzed data from more than 270,000 participants in the UK Biobank, using observational data and genetic techniques to assess the relationship between blood levels of these amino acids and mortality and life expectancy.
Although initial findings suggested that both amino acids might increase the risk of premature death, careful analysis showed that only tyrosine carried a strong causal relationship.
Genetic estimates suggest that men with high levels of tyrosine may lose approximately one year of their life expectancy, while the results did not show a statistically significant effect on women.
The researchers confirmed that these results remained consistent even after accounting for associated factors, including phenylalanine levels. They also noted that men tend to have higher tyrosine levels than women, which may partially explain the difference in life expectancy between the sexes.
The precise mechanisms underlying this effect are still being studied, but it is believed that the role of tyrosine in insulin resistance and the production of stress-related neurotransmitters may be contributing factors.
Although tyrosine is commonly used as a supplement to enhance cognitive function, this study raises questions about its long-term effects on aging. While the research did not directly examine supplements, its findings suggest that individuals with high tyrosine levels may benefit from dietary modifications, such as reducing protein intake, which could help lower tyrosine levels and support healthy aging.
More studies are needed to confirm these findings and explore whether dietary and lifestyle changes can safely lower tyrosine levels to promote longevity.
