Chemicals from gut bacteria improve health in old age

Molecules made by bacteria in the stomach could improve quality of life during old age, a new study has found.

Researchers proved that these molecules – known as indoles – improved the health of a variety older animals, raising hopes that they could also positively affect elderly humans.

The indoles made them more mobile and more resistant to infection and stress caused by heat. And for some, the indoles increased the amount of time they are usually fertile.

The way that elderly humans could safely consume more of chemical is not yet known but the study’s researchers are optimistic about its ability to have similar effects on humans.

A new study found that a molecule produced by gut bacterium can improve the health of old animals. Researchers are hopeful that it can do the same for humans (file photo)

The researchers – from Atlanta’s Emory University – studied mice, worms and flies. 

Study author Dr Daniel Kalman said his team wanted to figure out how to make elderly animals healthier.

The researchers were interested in the ‘healthspan’ of the animals, which is the amount of time an aging animal – or human – can resist stress and stay active.

The focus of the research was not on how to make animals live longer but instead on how to make them healthier in their old age.

‘The point of the paper is to identify this class of molecules as one we can pursue with that goal in mind,’ Dr Kalman said.

Dr Kalman’s lab proved that indoles and similar molecules made worms and mice more resistant to infection and stresses.

Researchers fed the worms bacterium that produce indoles and compared them with worms who did not receive the same bacterium.

The indoles did not change the worms’ lifespans but those that were fed the indole-producing bacterium had a better health span.

They had increased mobility, strength and resistance to stress caused by heat.


There number of bacterium in your stomach alone is higher than that of cells in your entire body.

Probiotcs are a source of good bacterium that act the same as bacterium found in your body. 

An imbalance of good and bad bacterium – which can be caused by an unhealthy diet – can lead to problems such as constipation, weight gain and diarrhea.

Foods that have probiotics include:

  • yogurts
  • cheeses
  • sauerkraut
  • kimchi

And the indoles more than doubled the usual amount of time the worms can reproduce, which jumped from five days to 12.

The study showed that fruit flies and mice that received the indoles also had improved heat resistance and mobility.

And they helped old mice – who were 28 months – maintain their activity levels and their weight.

The researchers also tested the effects of indoles on younger mice and found that indoles make the amount of time a mouse will live after being exposed to lethal radiation longer.

Dr Kalman is hopeful about what this study could mean for human longevity.

‘They probably do it in people, too,’ he said. ‘Those molecules have an effect on us and our immune system and physiology.’

He said that while they gave indoles to some of the animals they studied orally, the way to give them to older humans is still unclear.

‘We’re not there yet – that’s a rather long process,’ he said, adding that researchers do not know how to give indoles to humans safely.

But he said that research that will allow scientists to solve that problem is being planned.

‘It is the question the public should be asking,’ he said.

‘The longer you live the more frail you get. The idea [that] we can live healthier for longer – that’s a key goal.’