A common amino acid found in protein-rich foods and many brain health supplements may have an unexpected connection to longevity, according to new research.
Scientists reporting in magazines Aging-United States We investigated whether two amino acids, phenylalanine and tyrosine, affect human longevity (lifespan). Their findings suggest that high levels of tyrosine in the blood are associated with shorter life expectancy in men, raising new questions about the role this nutrient plays in aging.
The research was conducted by Jie V. Zhao, Yitang Sun, Junmeng Zhang, and Kaixiong Ye from the University of Hong Kong and the University of Georgia.
What are phenylalanine and tyrosine?
Amino acids are often described as the building blocks of proteins. The body uses them to create and repair tissues, produce enzymes, and support a myriad of biological functions.
Phenylalanine and tyrosine are two amino acids that help regulate metabolism and brain activity. They occur naturally in many foods, especially meat, fish, eggs, dairy products, and other protein-rich sources. They are also available as dietary supplements marketed for energy, focus, and cognitive performance.
Tyrosine is especially noteworthy because it helps the body produce neurotransmitters such as dopamine, noradrenaline, and epinephrine. These chemical messengers play important roles in mood, attention, motivation, memory, and the body’s response to stress.
These functions have made tyrosine of increasing interest among researchers studying aging, brain health, and longevity.
Analysis of research involving over 270,000 people
To investigate whether these amino acids influence longevity, researchers analyzed health and genetic information from more than 270,000 participants enrolled in the UK Biobank, one of the world’s largest long-term health databases.
The team used two complementary approaches. First, they examined the observed relationship between amino acid levels and mortality. They also used a technique called Mendelian randomization. This is a genetic technique that helps scientists determine whether an observed association reflects a causal relationship rather than simple chance.
This combination allowed the researchers to go beyond correlation and obtain stronger evidence as to whether amino acid levels directly affect lifespan.
Tyrosine stands out as a potential longevity risk
At first glance, both phenylalanine and tyrosine appeared to be associated with an increased risk of death. However, after more detailed analysis considering additional factors, only tyrosine continued to show a consistent relationship with longevity.
The findings suggested that elevated tyrosine levels may contribute to shorter life expectancy in men.
Based on genetic analysis, researchers estimated that elevated tyrosine levels could shorten a man’s lifespan by nearly a year.
The same pattern was not found for women. This study found no significant association between tyrosine levels and longevity among female participants.
The researchers also noted that men generally have higher tyrosine levels than women, which may help explain some of the long-observed differences in life expectancy between men and women.
“After controlling for tyrosine, phenylalanine showed no association with longevity in either men or women.”
Why does tyrosine affect aging?
Scientists still don’t know exactly how tyrosine affects longevity, but several possibilities have emerged.
One possible explanation has to do with insulin resistance, a condition in which the body’s cells become less responsive to insulin. Insulin resistance is associated with a variety of age-related health problems, including type 2 diabetes, cardiovascular disease, and metabolic disorders.
Tyrosine can also affect the production of neurotransmitters involved in the body’s stress response. Over time, disruptions to these systems can impact long-term health and aging.
Researchers believe hormone-related pathways may also play a role. These biological pathways may function differently in men and women, which may help explain why the apparent longevity effects were observed only in men.
What does this mean for supplements?
Tyrosine is frequently sold as a supplement to support concentration, mental performance, and alertness, especially in stressful situations.
But new findings suggest there may be more to the story when considering long-term health.
Importantly, the researchers did not directly investigate tyrosine supplements or test whether taking tyrosine supplements shortened lifespan. Instead, the study focused on blood levels of naturally occurring amino acids and how those levels are associated with longevity.
As a result, the results of this study should not be interpreted as evidence that tyrosine supplements are harmful. Nevertheless, they suggest that elevated tyrosine levels may be worth further investigation.
Researchers note that dietary strategies such as reducing overall protein intake may help lower tyrosine levels. Future research will be needed to determine whether such approaches can safely improve healthy aging and longevity.
further research is needed
This study provides some of the strongest evidence to date linking tyrosine and longevity, but many questions remain unanswered.
Scientists need to confirm their findings in larger populations to better understand the biological mechanisms involved. Researchers also want to know whether diet, lifestyle changes, or other interventions could safely lower tyrosine levels and promote healthier aging.
So far, the study highlights an interesting possibility. A nutrient best known for supporting brain chemistry may also have an unexpected connection to human longevity.
