Led by Vijay Yadav from Columbia University in New York, the researchers also conducted a trial that found that older mice (the equivalent of 60 in human years) receiving taurine supplementation for one year were healthier in almost every way compared to their unsupplemented counterparts.
In female mice, taurine supplementation suppressed age-associated weight gain in female mice (even in “menopausal” mice), increased energy expenditure, increased bone mass, improved muscle endurance and strength, reduced depression-like and anxious behaviors, reduced insulin resistance, and promoted a younger-looking immune system, among other benefits.
“Not only did we find that the animals lived longer, we also found that they’re living healthier lives,” said Yadav.
Attention
The study has garnered a lot of attention in the mainstream media, with headlines such as:
Common energy drink ingredient taurine ‘may slow ageing process’ (The Guardian); Is taurine the ‘elixir of life’? Maybe, if you’re a worm, mouse or monkey (CNN); Can Taurine, Found in Energy Drinks, Slow Down Aging? (The New York Times); and Can Taurine Slow Aging? Here's What the Latest Science Says (Time).
Taurine is an amino sulfonic acid that occurs naturally in meat and fish. We can also produce it enzymatically in our bodies from cysteine. Scientists have already reported that taurine plays a role in building bone, and taurine levels are correlated with immune function, obesity, and nervous system functions.
“We realized that if taurine is regulating all these processes that decline with age, maybe taurine levels in the bloodstream affect overall health and lifespan,” said Yadav.
Analysis of blood samples taken from mice, monkeys, and people revealed that taurine abundance decreases substantially with age. For example, taurine levels in 60-year-old humans were only about one-third of those found in 5-year-olds.
Yadav and his co-workers then performed a large trial with middle-aged lab mice (about 45 years old in people terms) and fed them either taurine or a control solution for the rest of their lives. This revealed that the lifespan of taurine-fed animals increased by 12% in females and 10% in males. This would translate to about seven to eight years for humans.
These findings were repeated in subsequent studies with monkeys. In those experiments, six months of taurine supplements was associated with less weight gain, lower fasting blood glucose and markers of liver damage, increased bone density in the spine and legs, and improved the health of their immune systems.
Commenting on the potential mechanism(s) of action, the researchers noted that the compound was found to decrease the number of “zombie cells” (old cells that should die but instead linger and release harmful substances), increased survival after telomerase deficiency, increased the number of stem cells present in some tissues (which can help tissues heal after injury), improved the performance of mitochondria, reduced DNA damage, and improved the cells‘ ability to sense nutrients.
Translation to humans?
The big question now is whether such benefits would extend to humans. This remains unanswered, but the researchers did conduct two experiments to support taurine’s potential in humans.
In the first study, the researchers explored the relationship between taurine levels and approximately 50 health parameters in 12,000 European adults aged 60 and over. This data revealed that, in general, people with higher taurine levels were healthier, with lower incidence of type 2 diabetes, obesity, hypertension, and levels of inflammation.
“These are associations, which do not establish causation,” said Yadav, “but the results are consistent with the possibility that taurine deficiency contributes to human aging.”
The researchers also examined if taurine levels would respond to exercise by measuring levels before and after a variety of male athletes and sedentary individuals finished a strenuous cycling workout. This study revealed a significant increase in taurine among all groups of athletes (sprinters, endurance runners, and natural bodybuilders) and sedentary individuals.
“No matter the individual, all had increased taurine levels after exercise, which suggests that some of the health benefits of exercise may come from an increase in taurine,” said Yadav.
While randomized clinical trials are currently underway to assess the efficacy of taurine in obesity, none are designed to measure a wide range of health parameters.
While drugs such as metformin, rapamycin, and NAD analogs are being considered for testing in anti-aging clinical trials, Yadav said that taurine should be added to this list.
“And it has some advantages: Taurine is naturally produced in our bodies, it can be obtained naturally in the diet, it has no known toxic effects (although it’s rarely used in concentrations used ), and it can be boosted by exercise,” he said.
“Taurine abundance goes down with age, so restoring taurine to a youthful level in old age may be a promising anti-aging strategy.”
Caution
In an accompanying perspective in Science, Joseph McGaunn and Joseph Baur from the University of Pennsylvania noted, “A key issue for any longevity intervention is whether it causes calorie restriction (which can extend life span) or acts through independent mechanisms. Singh et al. found that taurine supplementation did not affect food intake in mice but nonetheless caused a small decrease in body weight, indicating a calorie deficit.
“Energy expenditure was higher in taurine-treated mice and intestinal transit time was accelerated, although it is not clear if nutrient absorption was decreased. The change in intestinal behavior is intriguing, because taurine is conjugated to bile acids to form bile salts, which facilitate uptake of dietary lipids. It will be crucial to control for the effects of taurine on body composition and nutrient uptake in future studies.”
They also sounded a note of caution about extrapolating the results to humans.
“Whether taurine supplementation influences human longevity is also unknown,” they noted. “Taurine can act as a γ-aminobutyric acid type A (GABA-A) and/or glycine receptor agonist to promote neuronal inhibition. Whether this might play a role in the beneficial effects of taurine on anxiety and memory in mice, observed by Singh et al., or might have less desirable effects on neurotransmission remains unclear.”
They also noted that while the new study reported benefits for taurine on bone health, other studies in mice have reported detrimental effects on bone microstructure.
“A singular focus on increasing dietary taurine risks driving poor nutritional choices, because plant-rich diets are associated with human health and longevity,” wrote McGaunn and Baur. “Thus, like any intervention, taurine supplementation with the aim of improving human health and longevity should be approached with caution.”
Source: Science
2023, Volume 380, Issue 6649, doi: 10.1126/science.abn92
“Taurine deficiency as a driver of aging”
Authors: P. Singh, et al.
