London - Drinking red wine boosts good bacteria in your gut, researchers have found.
They say the impact on the "gut microbiome" – which helps support the immune system and metabolism – could finally explain the beneficial effects of red wine.
A study of nearly 3 000 people, including 900 British twins, found those who drink red wine have a significantly better balance of good to bad gut bacteria.
Researchers at King’s College London analysed the impact of beer, cider, spirits and white and red wine on the gut microbiome of 916 female twins.
The balance of bacteria was significantly better in red wine drinkers. They also had lower cholesterol and were less likely to be obese.
Even among pairs of twins, who share their DNA and upbringing, if one sister preferred red wine then her gut bacteria would be significantly healthier than her sister’s.
The researchers compared their results to similar experiments in the US and Holland, involving another 2 000 people, and found the trend held true.
Red wine seemed to have a significant impact even among those who said they had a glass only once every two or three weeks. The academics believe this is down to polyphenols – defence chemicals naturally present in grapes – which they think acts as fuel for good bacteria.
Researcher Dr Caroline Le Roy, whose work is published in the Gastroenterology medical journal, said: "While we have long known of the unexplained benefits of red wine on heart health, this study shows that moderate red wine consumption is associated with greater diversity and a healthier gut microbiota that partly explain its long-debated beneficial effects on health."
An imbalance of "good" microbes compared to "bad" in the gut can lead to adverse health outcomes such as reduced immune system, weight gain or high cholesterol.
A person’s gut microbiome with a higher number of different bacterial species is considered a marker of gut health.
The team found that the gut microbiota of red wine drinkers contained a greater number of different bacterial species.
But it’s no excuse to work your way through a whole bottle. Dr Le Roy said: "Drinking red wine once every two weeks, seems to be enough to observe an effect. If you must choose one alcoholic drink today, red wine is the one to pick. However, it is still advised to consume alcohol in moderation."
Scientists said the study may pave the way for researchers to eventually extract the benefits from red wine in order to develop a medical treatment.
Professor Kim Barrett, of the University of California San Diego, said: "In the long run, this work might suggest (perhaps less pleasurable) ways to obtain the apparent health benefits of red wine consumption without drinking the wine itself, although more work would be needed to isolate and test the components of red wine that are responsible for the effects seen here."