Men who drink a beer a day have more diverse gut bacteria, study finds

• A study found that both alcoholic and non-alcoholic beer increased men's gut bacteria diversity.
• Drinking one beer with dinner could increase gut diversity without weight gain, the study found.

Drinking a beer a day could improve the diversity of men's gut bacteria, even if it's non-alcoholic, according to a small study.

To understand the effect of alcoholic and non alcoholic beer on the diversity of gut bacteria, researchers from Nova University Lisbon, Portugal, asked 19 healthy adult men to drink 11 oz (325 ml) of alcoholic or non-alcoholic lager with dinner every day for four weeks. The alcoholic beers contained 5.2% Alcohol by Volume, which is considered strong.

The men in the study were 35 years old on average. They drank the same amout of alcohol on average before the start of the study, and were considered to be moderate alcohol drinkers.

The study authors chose alcoholic and non-alcoholic beers that were as similar as possible, the main difference being the alcohol content. The men didn't know which type of beer they were drinking and were told not to change their dietary or exercise habits during the trial.

Blood and stool samples were collected and their gut microbiota were analyzed before and after the experiment.

The findings were published in the Journal of Agricultural and Food Chemistry.

The men had more diverse gut bacteria after drinking beer with dinner for four weeks

Researchers found not only a more diverse set of microbes across the board in the men's guts at the end of the study, but also no change in weight or BMI, and no new signs in the blood of heart or metabolism problems.

The men also had higher levels of fecal alkaline phosphatase, which is an indicator of better intestinal health, according to the authors.

The researchers said further research involving more participants is needed to back up their findings, and their study also didn't assess the effect of non-alcoholic beer on the diversity of gut bacteria in people who don't usually drink alcohol.

The study is not the first to link beer consumption with increased gut bacteria diversity, however previous research only found benefits from non-alcoholic beer.

It's thought that the polyphenols in beer and the microorganisms that result from the fermentation process are good for the gut.

A diverse gut isn't always necessarily healthy though, but it increases the likelihood of having "good" microbes, Dr. Vincent B. Young, a professor at Michigan State University's Department of Microbiology and Immunology who wasn't involved in the study, told Healthline.

Dr. Ashkan Farhadi, a gastroenterologist at MemorialCare Orange Coast Medical Center, California, who also wasn't involved in the research, told Healthline a lack in the number and diversity of gut bacteria is linked with many conditions.

"So diversity, in general, is typically a good sign, but I don't read more than that into it," he said.

Reduced gut bacteria diversity has been seen in people with heart disease and diabetes

The gut microbiome is made up of trillions of microscopic organisms that are important for digestion and overall health, Insider's Adam Barnes previously reported.

Low levels of gut bacteria diversity have been found in people with a range of conditions, including heart disease and diabetes.

When the balance of "good" and "bad" bacteria of the microbiome is disturbed, it can lead to diarrhea, constipation, gas, and stomach pain, among others. Alcohol can play a role in throwing this balance off.

Gut health-boosting foods and drinks include kimchi, sauerkraut, kefir, yogurt, miso, kombucha, and pickled vegetables.

Fermented foods can lead to bloating and gas though, so increasing your servings gradually is recommended.