How a humble cuppa could help us to live longer

The health benefits of drinking tea and coffee – quite apart from the stimulating boost craved by many thanks to the presence of caffeine – also include prolonging life, Chinese scientists have found.

Both drinks are rich in a safe, non-addictive natural compound that even in modest dosages has been found to increase the age of worms up to the human equivalent of 175 years, says a new study by university researchers.

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They said they hoped their findings, published in the latest issue of The Journals of Gerontology: Series A – a peer-reviewed publication run by the Gerontological Society of America – would form the basis for developing drugs that could be used to influence the ageing process.

The chemical found in tea and coffee, called chlorogenic acid (CGA) – also found in prunes, potatoes and aubergines – is an antioxidant that takes its name from the Greek word “chlorogenic”, meaning “give rise to light green”.

CGA, which acts as an intermediator in the process of plant biosynthesis, produces a green colour when exposed to the air.

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Previous studies in recent years found that CGA, which is abundant in tea, coffee and honeysuckles, has many health benefits including improving brain performance, speeding up the healing of wounds, and reducing the risk of cancer, as well as Parkinson’s and Alzheimer’s disease. But its overall effect on ageing has remained unknown.

Professor Luo Huairong and her colleagues at the Chinese Academy of Sciences’ Kunming Institute of Botany sought to find clues by feeding CGA to C aenorhabditis elegans, a roundworm with a tiny, transparent body.

The worm has an ageing process similar to mammals and humans, but lives only two to three weeks.

This provided scientists with a convenient model to study the causes and mechanism of ageing.

On average, the study found worms fed CGA were able to live up to 25 per cent longer than those that did not receive the antioxidant.

The oldest worms lived for 35 days – the equivalent of 175 human years – and were healthier, too.

“Coffee and tea are two of the most popular drinks around the world,” the researchers wrote in the paper.

“The research on these two drinks has been revealing more and more in common from chemical components to their impacts on human health.

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The findings might serve as a starting point for developing foods with health-giving additives or pharmaceutical interventions in the ageing process, they said.

The worms fed with CGA remained physically active for longer, while their immune system was more responsive in fighting infectious diseases.

They had a higher chance of survival in the face of environmental stress, such as sudden increases in temperature and water pollution.

The best dosage of CGA was found to be 50 micromoles - a unit measuring a tiny amount of a substance. The study found that providing either too high or too low a concentration of the antioxidant would fail to produce the optimal results, but in general worms given the chemical tended to live longer than those that did not have it.

But why did it make a difference? The researchers found that CGA could manipulate the functioning of certain genes to stimulate insulin secretion and prevent the build-up of fat in an animal’s body, which is closely related to the ageing process.

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On worms with the related genes knocked out, the scientists found that CGA could not produce any life-prolonging effects.

However, the study did not answer all questions: nobody is known to have lived for 175 years by drinking tea or coffee. This is because the ageing process is influenced by many other factors such as a person’s genes, environment and life habits, including smoking.

There have also been contradictory findings in the research community. Although some scientists have found evidence suggesting that drinking tea or coffee has positive health effects, others have reported negative results, with the debate centring mainly on caffeine.

Some studies have found that caffeine can accelerated the ageing of skin, while others found it prevented skin cancer; some studies said it reduced blood pressure, while others warned it increased the risk of heart disease; some suggested caffeine helped to prevent age-related brain disease, but others alleged it damaged our nervous system.

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The uncertainty was partly a result of the addictiveness of caffeine, according to a study by the Johns Hopkins University School of Medicine in 2012. The benefits, such as an increase in work performance, could be offset by the difficulties people experienced when they went without caffeine, such as depression, irritability, anxiety and poor sleep.