Study challenges taurine as a biomarker of aging

Research in animals and humans has suggested low levels of taurine may be a driver for aging, which has led to discussions about whether taurine is an aging biomarker. Now, a comprehensive study involving longitudinal data from humans, monkeys, and mice shows that taurine levels in the blood do not consistently decline with age, and that levels of taurine vary more by factors unique to each individual than based on aging.

These results lead the study authors – Maria Fernandez and colleagues – to conclude that "the efficacy of taurine supplementation to delay aging or broadly treat aging-related conditions may be context-dependent." The micronutrient taurine is one of the most abundant amino acids in animals and is recognized for its wide-ranging biological roles and potential health benefits. Some recent studies, including a June 2023 Research Article published in Science, have shown that taurine levels in the blood decline with age in organisms studied, and that taurine supplementation may delay this process and improve healthy lifespan. These and other results have also prompted discussions about whether taurine levels could potentially offer a blood-based biomarker for aging.

In order to qualify as a true biomarker of aging, taurine must reliably change with age across diverse populations and over time, ideally evidenced through longitudinal data. According to Fernandez and colleagues in their new paper, earlier studies – mostly based on cross-sectional data – have yielded conflicting findings about how taurine levels in the blood change with age.

Building upon this past work, Fernandez et al. conducted comprehensive longitudinal and cross-sectional analyses of taurine levels in three distinct large human cohorts, rhesus monkeys, and mice across a broad age range. They found that circulating taurine concentrations either remain stable or increase with age in healthy individuals, and that variations in taurine levels were more influenced by individual differences, diet, sex, and species than by aging itself. The findings also revealed that associations between taurine and functional indicators of health, such as muscle strength and body weight, varied depending on context and species. The findings did not consistently support a causal link between declining taurine and aging. Based on these findings, Fernandez et al. conclude that taurine is not a reliable biomarker of aging and that its potential as an anti-aging therapy is more likely context-specific rather than universal.