Researchers from the University of Hong Kong in China and the University of Georgia in the United States analyzed genetic and health data from more than 270,000 people and found that men with higher levels of tyrosine in their blood tended to have a slightly shorter life expectancy.
The study focused on phenylalanine and tyrosine, two amino acids found in protein-rich foods and some supplements. Among men, higher tyrosine levels were associated with a reduction of nearly one year in life expectancy. The same association was not observed in women. Phenylalanine, meanwhile, showed no independent association with life expectancy after tyrosine levels were taken into account.
To determine whether the relationship could extend beyond a simple correlation, the researchers used a technique known as Mendelian randomization, which uses naturally occurring genetic differences to assess potential causal relationships.
The researchers said the mechanisms behind the association remain unclear. Possible explanations include a relationship with insulin resistance and brain processes involving tyrosine.
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However, the authors emphasized that the findings do not show that consuming tyrosine-containing substances reduces longevity. The study did not examine specific products or supplements.
Tyrosine is used in some supplements marketed to support mental performance. The amino acid helps the body produce dopamine, adrenaline and other brain chemicals involved in mood, concentration and the response to stress.
