A team of scientists in China said they have discovered how a type of bile known as lithocholic acid (LCA) can slow down ageing in a way similar to how calorie restriction or fasting work.
The team found that LCA, a naturally occurring acid compound in humans and animals that is produced in the liver, is a metabolite that alone can reproduce starvation effects in mice – resulting in muscle regeneration and even enhancing grip strength and running capacity.
The findings of the study, led by Xiamen University, were published in two articles in the peer-reviewed journal Nature on Thursday.
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During calorie restriction, LCA is accumulated in mammals and activates the energy sensor enzyme AMPK, a master metabolic regulator.
AMPK, which is naturally activated when glucose levels become low, is important for anti-ageing because it regulates various cellular processes, including inflammation and neurodegeneration.
To activate it without fasting is to induce a state of pseudo-starvation.
In the study, the scientists took blood serum from mice that had undergone calorie restrictions for four months and put it into mice that had not been subjected to dietary restrictions.
They found that the serum led to AMPK activation in the liver and muscle and a consistent, but not statistically significant, increase in their median lifespan.
The LCA concentration in the serum was far below the level that would cause harmful effects, such as DNA damage or tumour development, while it remained effective in activating AMPK, the researchers said.
They also administered LCA to nematode worms and fruit flies – neither of which are able to synthesise the acid naturally – and found that it activated AMPK and induced life and significant health-extending effects on the animals.
The results indicated that the researchers were able to transmit the signalling effects of LCA once administered.
LCA increased the mean lifespan of nematodes from 22 to 27 days, while in flies, it extended male lifespan from 47 to 52 days and that of females from 52 to 56 days.
Lead author Lin Shengcai, a metabolic biologist at Xiamen University, said the team was exploring the potential application of LCA pills for humans in trials.
The acid is not listed as a legal compound by China’s drug authorities for use in humans, although it exists in Niuhuang, a dried gallstone found in cows that is used in Chinese medicine. The acid could also be synthesised in laboratories.
“We will address the challenges and complexities to explore how it can be applied to humans of different ages with various health conditions, such as pregnancy, and determine the appropriate dosage,” Lin said.
“People have long sought an elixir for longevity. LCA is one possibility, as it represents one molecule in the blood of people practising calorie restriction and activates AMPK, which in turn further induces metabolite changes in the blood.”
More from South China Morning Post:
- How the Mediterranean diet helps you age well by protecting brain and body health
- How your liver keeps you healthy and how hepatitis vaccinations and a good diet can protect it
- Gastrointestinal cancers: lifestyle changes to lower risk factors you can make – it’s World Digestive Health Day
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