Taurine is not a reliable biomarker of aging, according to research that runs counter to suggestions that supplementation could be an easy way to improve longevity.
The findings, in the journal Science, dispute earlier studies indicating levels of the amino acid decline with age and its potential as an anti-aging therapy.
The study revealed that circulating levels of taurine did not decline with age in three mammalian species, including humans, across the adult lifespan and, in fact, increased among women.
Differences between individuals were also generally greater than the longitudinal changes across lifespan, limiting its utility as a biomarker of aging.
Furthermore, the association between taurine levels and functional measures of health status depended on the context in which they were studied—such as the age, species, or group. This undermined the idea that reduced circulating concentrations promoted an aging phenotype.
“The reality is that at the current state of our knowledge there is no supplemental or supplement that truly improve longevity or health,” researcher Luigi Ferrucci, MD, PhD, from the National Institute on Aging in Baltimore, told a press briefing.
He added: “I’ve been a practicing physician for a long time, and you know my recommendation when people ask me about supplements is, try to have a balanced diet.”
Taurine serves numerous critical biological roles, the researchers note. It is involved in the conjugation of bile acids, cellular redox, osmoregulation, membrane stabilization, and modulation of calcium signaling.
Taurine supplementation has particularly been linked with potential benefits against oxidative stress and inflammation, in the regulation of glucose, and cholesterol homeostasis and for improving physical performance, although clinical trials have remained inconclusive.
Nonetheless, trials on taurine supplementation have shown a positive effect on cardiovascular diseases, some but not all markers of metabolic disease, and mixed results for markers of physical performance.
Studies have also indicated that taurine levels decrease with age, and that supplementation could improve both lifespan and healthspan—the duration lived without chronic disease or disability.
Ferrucci and colleagues assessed circulating taurine levels in mice, nonhuman primates and three distinct cohorts of healthy humans in a study that involved repeated measurements in the same individuals.
The results revealed a complex picture that showed large variations in circulating levels between individuals, with taurine levels increasing as women aged and no clear association of taurine concentrations with measures of health status.
“On the basis of these findings, we conclude that low circulating taurine concentrations are unlikely to serve as a good biomarker of aging,” the researchers concluded.
“Moreover, we surmise that the efficacy of taurine supplementation to delay aging or broadly treat aging-related conditions may be context dependent.”
