"Lose weight and still drink wine! It's good for your gut and keeps you slim," reports the sun.
Like many titles "too good to be true", the story is more complicated than that.
The researchers examined the self-reported drinking habits of 916 binoculars in the UK and cross-checked their results with similar groups in the United States and Belgium.
They also evaluated microorganisms, such as bacteria, living in women's intestines. A more diverse population of intestinal microorganisms has been associated with better intestinal health.
They discovered that women who drank red wine had more diverse intestinal microorganisms.
They also noted that women who drank red wine tended to have lower body mass index (BMI), which their analyzes suggested could be related to the effect on intestinal microorganisms.
The researchers hypothesized that the chemicals called polyphenols found in red wine could create favorable conditions for a greater diversity of intestinal microorganisms.
But because of the type of study it is, it is not possible to say whether red wine was the cause of bowel diversity or lower BMI.
Other factors may have been involved, such as the overall lifestyle of women. Researchers have tried to adapt to the impact of certain factors, but it is difficult to eliminate them completely.
Drinking red wine is not recommended as a way to lose weight. And this study also did not prove that it could help the health of your intestines.
As researchers have explained, any potential beneficial effect on red wine consumption could possibly be achieved by drinking only one glass of red wine every 2 weeks.
Drinking regularly more than the recommended limits (14 units of alcohol per week) can expose you to a range of long-term health problems, such as liver disease and cancer.
Learn more about the risks of drinking too much alcohol
Where does the story come from?
The researchers who conducted the study belonged to King & # 39; s College London and the Rega Institute for Medical Research in Belgium.
The study was published in the peer-reviewed journal Gastroenterology, although at the time of writing this document, it is not available on their website.
We reviewed a version available to the media, which may differ from the published final version and not include additional material.
As might be expected, some British media have jumped on the link between red wine and weight.
Although the study does not show that red wine causes a lower BMI, the headlines indicate that red wine "helps drinkers to avoid obesity" (Mail Online), "is healthier for the belly and the figure "(The Times) or" can help you stay slim "(the sun).
BBC News reports were more balanced.
What kind of research was this?
This was a cross-sectional study of women who had previously participated in twin research.
Twins are often recruited for studies to evaluate the relative impact of genetics and the environment on people's health.
Cross-sectional studies provide insight into time of different factors, such as alcohol consumption, intestinal composition of microorganisms and BMI.
But they do not show how these can change over time, nor how they are related.
What does the research involve?
The researchers analyzed information on women who had participated in 3 separate twin studies before.
In these studies, women reported their alcohol consumption in food frequency questionnaires.
They reported how many drinks they drank in an average month of:
- beer or cider
- Red wine
- White wine
- any alcohol (total)
The researchers calculated the biodiversity of intestinal microorganisms of the female population, presumably from stool samples, although this information was not reported in the main research paper.
The researchers examined whether the consumption of different types of alcohol was related to the intestinal diversity of microorganisms.
They adjusted the numbers to account for women:
- healthy eating (an index derived from responses to food frequency questionnaires)
- family structure
They also looked at whether the diversity of intestinal microorganisms could affect the relationship between women's alcohol consumption and BMI, fasting blood glucose, insulin, total cholesterol , LDL ("bad") and HDL ("good").
The researchers initially examined data from 916 British women.
For the analyzes where they found a link, they were then repeated in 2 other groups of women from the United States (904 women) and Belgium (1,104 women).
What were the basic results?
The consumption of red wine was related to the diversity of intestinal microorganisms, with more frequent consumption linked to greater diversity.
Even those who rarely drank red wine appeared to have a greater diversity of intestinal bacteria.
Red wine drinkers had more diversity of intestinal bacteria than those who did not drink red wine.
This was observed in the three groups of women (British, American and Belgian).
White wine (which contains fewer chemicals called polyphenols) was also related to the diversity of intestinal microorganisms, but less strongly than red wine.
Other types of alcohol were not related to the diversity of intestinal microorganisms.
But the researchers said that "the frequency of red wine consumption accounted for only a modest proportion" of the diversity between individuals.
The link was mainly observed for 3 types of microorganisms.
The researchers said that red wine consumption was linked to lower BMI, and statistical tests suggested that this could partly be explained by the intestinal diversity of microorganisms in the British and American groups, but not in the Belgian group.
But these figures were not included in the version of the document we received, so we can not comment on them in detail.
For example, we do not know what difference there was between BMI of women who drank red wine and those who did not drink it.
How did the researchers interpret the results?
The researchers said, "We have demonstrated that red wine consumption is positively associated with" the diversity of intestinal microorganisms, and that "our findings suggest that even a rare intake may be sufficient" to increase diversity.
They added: "We have also shown that this can contribute to some of the health benefits of moderate red wine consumption, although not yet debated, such as improving cholesterol metabolism or reducing fatness. . [body fat]. "
When a title seems too good to be true, it is usually the case. Nothing in this study suggests that people should start drinking red wine to lose weight.
The potential effect of the diet on intestinal microorganisms is a new and interesting area of science.
This study provides new evidence on a possible effect of the substances present in red wine on the growth of microorganisms in the intestine and suggests that this could affect the functioning of the body.
But the study has several limitations. Because it's transversal, it only shows us a snapshot in time.
We do not know how intestinal microorganisms, BMI or women's red wine consumption have changed over time.
This means that we can not say if any of these factors could directly influence each other.
As this was an observational study, we do not know if red wine was causing differences in BMI or intestinal microorganisms.
Other factors may have been involved, such as the general lifestyle of women.
Researchers have tried to adapt to the impact of certain factors, but it is difficult to eliminate them completely.
In addition, the study relied on women's reports of the amount of alcohol they drank. People often underestimate their consumption of alcohol.
We know that there is a big drawback to the consumption of alcohol, especially in excess. There is no "safe" level of alcohol, but consuming less than 14 units of alcohol a week is considered low risk.
Drinking regularly more than that increases the risk of several types of cancer, stroke, heart disease, liver disease, brain damage and nervous system problems.
For people who like a glass of red wine on occasion and drink less than 14 units a week, this study suggests that they may have a more diverse intestinal flora.
But there is no reason to start drinking red wine in hopes of improving bowel health or losing weight. The study does not provide enough evidence.
Learn more about alcohol units and how to drink within the recommended limits
Analysis by Bazian
Published by the NHS website
Links to titles
The sun, August 28, 2019
BBC News, August 28, 2019
ITV News, August 28, 2019
Mail Online, August 28, 2019
The Times (subscription required), August 28, 2019
Links to science
Gastroenterology. Posted August 28, 2019