Here's why coffee drinkers can live longer

Drinking coffee may have a protective effect against an inflammatory mechanism associated with ageing and the chronic diseases that come with it. Caffeine could in particular help elderly people who suffer from cardiovascular diseases.

Cardiovascular diseases are the leading cause of death worldwide – in 2012 they represented 31% of all deaths globally. Older age is a risk factor for poor cardiovascular health, and as the world's population ages, there is a concern that rates of cardiovascular mortality will continue increasing.

This is even more worrying as no treatment exists to target and prevent age-associated cardiovascular diseases, because not enough is known about what causes the progressive health deterioration that people can go through as they become older.

In a study published in Nature Medicine, scientists from Sanford University have identified a chronic inflammatory process that occurs in some elderly adults and is associated with a heightened risk of developing cardiovascular problems. Drinking coffee could however help them live longer.

Genes and inflammation

The scientists looked at blood samples, survey data and medical and family histories collected from more than 100 participants from the Stanford-Ellison cohort, a long-term programme by the university which was established 10 years ago to study ageing.

The participants were aged between 20-30 or older than 60 and were monitored each year with blood tests, surveys and analysis of their medical histories.

Here, the scientists compared blood samples from the two age groups to identify which genes were more activated with old age. Two clusters of genes were seen as particularly interesting – activated in elderly participants, they were associated with the production of a circulating inflammatory protein called IL-1-beta.

For some of these older adults, these genes were much more activated than for others. This led to an important production of the inflammatory protein and put these individuals at risk of having high blood pressure and stiff arteries – and thus of developing cardiovascular diseases.

Experiments with mice further confirmed this link, since increased IL-1-beta production in the animals triggered massive systemic inflammation, high blood pressure and renal pressure.

A link with caffeine

Past studies have shown that coffee drinkers live longer and are less prone to cardiovascular problems than non-coffee drinkers. In this research, the scientists uncovered a connection between the age-related inflammatory process and people's caffeine consumption, which may explain why that is.

Incubating immune cells with caffeine, the researchers indeed found that caffeine's own metabolites countered the action of the circulating inflammatory proteins. Caffeine therefore appeared to prevent cardiovascular disease and to help people live longer.

"That something many people drink – and actually like to drink – might have a direct benefit came as a surprise to us," said lead author Mark Davis. "What we've shown is a correlation between caffeine consumption and longevity. And we've shown more rigorously, in laboratory tests, a very plausible mechanism for why this might be so."