Washington (AFP)

Researchers have compared the effects of red wine on the intestinal flora to those of other alcohols and believe they have isolated a positive impact, according to a study published Wednesday that adds to several on the effects of red wine on health.

Scientists at King's College London studied 916 twins in the UK, including their reported consumption of beer, wine, cider and spirits, to determine possible differences in the diversity of gastrointestinal microbes (the microbiota), whose balance is crucial for the body.

Bacterial diversity was better in women who consumed relatively more red wine, while no positive association was found among other types of alcohol drinkers. A minor effect has been observed with white wine.

"The greater the diversity, the better it is for us, to prevent diseases and better metabolize food," says AFP principal author Caroline Le Roy, who notes that her study, published by the journal Gastroenterology, replicates in the real world results found in labs and on animals.

An imbalance between good and bad germs can in turn affect the immune system or be associated with weight gain or increased cholesterol.

- Alcohol remains bad -

This type of study is far from perfect. First because correlation does not mean causality. It is possible that other factors invisible to researchers have affected the microbiota of wine drinkers. Perhaps the good intestinal flora is due to other behavior or other ingredients not taken into account by the study.

Ideally, two large groups of people should be taken and one half of them randomly chosen to drink wine. But it is ethically complicated, since drinking alcohol is generally bad for health: alcohol is linked to 200 diseases, including mental problems, cardiovascular diseases and cirrhosis.

It is also almost impossible to measure the totality of what an individual eats and drinks. This still limits studies that claim to have an effect on the health of a single ingredient or type of diet.

That said, the researchers tried to strengthen their results by confirming them in two additional groups, a thousand participants in the United States and the Netherlands, as well as in another group of British twins.

The advantage of studying twins is that any differences observed are probably related to their environment, since they are genetically identical and have generally grown up in the same medium.

The study is to be considered in a set. Several others have previously shown various effects of a component of wine, polyphenols, coming from the skin of grapes.

For Nik Sharma, a neuroscientist at University College London, who did not participate in this study, work was likely to continue, perhaps on mice "to understand the underlying mechanisms".

But he praised a "serious" work, whose validity is reinforced by the use of twins and twins.

This should not be interpreted as a call to drink wine.

Fruits, vegetables, hazelnuts, chocolate and other foods are rich in polyphenols.

"You do not have to drink red wine, and you do not have to start drinking it if you do not drink," says Caroline Le Roy.

© 2019 AFP