Can a beer a day keep the doctor away? That’s what new research from Portugal suggests.

In a pilot study in the Journal of Agriculture and Food Chemistry, men who drank one can of alcoholic or nonalcoholic lager a day for four weeks improved the diversity of their gut microbiome, the collection of microbes that live in the intestinal tract.

A more diverse gut microbiome is linked to a lower risk of heart disease, diabetes, and severe COVID. So by promoting bacterial diversity, beer may help prevent these outcomes, the study suggests.diab

The findings stand out amid increasing evidence that no level of alcohol, even in small or moderate amounts, is good for you. This study indicates that a once-daily beer may benefit the gut microbiome regardless of its alcohol content, though nonalcoholic beer may still be the healthier choice.

“There are a lot of myths regarding beer,” says study author Ana Faria, PhD, a clinical nutritionist at NOVA Medical School in Lisbon. “We think it is important to know the impact of moderate consumption of this beverage.”

Giving New Meaning to “Beer Gut”

In this double-blind trial, 22 healthy men ages 23 to 58 were randomly split into two groups. One group drank 11 ounces of nonalcoholic lager every day for four weeks, while the other drank lager with 5.2% alcohol (comparable to Budweiser).

At the end of the four weeks, analyses of blood and fecal samples revealed an increase in more than 20 types of helpful bacteria in the men’s digestive tracts in both groups. Neither group saw significant changes in body weight, body fat, or cardiometabolic biomarkers such as blood sugar or LDL cholesterol, the researchers report.

Beer is rich in healthy compounds called polyphenols, which reduce inflammation and oxidative stress in the gut. This creates a favorable environment for beneficial bacteria to grow in, Faria explains.

What’s more, fermented foods have been shown to boost gut microbiome diversity, Faria notes. So the micro-organisms from beer’s fermentation may contribute as well.

So Is Beer a Health Food Now?

These findings both fit – and contradict – previous research exploring the impact of beer on the gut microbiome. One study, in the journal Alcohol in 2020, found that men and women ages 21 to 53 who consumed 12 ounces of nonalcoholic beer a day for 30 days saw an increase in gut microbiome diversity. However, a separate group who drank beer with 4.9% alcohol did not see the same improvement.

Why the different results between the two studies? It might come down to differences in the study participants, explains Khemlal Nirmalkar, PhD, an author on the 2020 study and a microbiologist at the University of Arizona.

While the 2020 study included men and women in Mexico, the 2022 study involved only “healthy men” in Portugal. Gut microbiome changes can be influenced by gender and body mass index, other research has found. And the fact that participants resided in different communities may also have had an impact, the Portuguese researchers noted in a press statement.

But nonalcoholic beer appeared to boost microbial diversity in people in both studies across the board, Nirmalkar notes. For now, that means nonalcoholic beer is likely the better bet for gut health, though more research is needed.

“There definitely should be more studies in this field with different beers and different alcoholic contents,” Nirmalkar says, noting that many people won’t drink nonalcoholic beer because they find the taste to be “a bit weird.”

Sources

Journal of Agriculture and Food Chemistry (2022). “Impact of beer and nonalcoholic beer consumption on the gut microbiota: a randomized, double-blind, controlled trial.” https://pubs.acs.org/doi/10.1021/acs.jafc.2c00587

Alcohol. (2020). “Influence of moderate beer consumption on human gut microbiota and its impact on fasting glucose and β-cell function.” https://doi.org/10.1016/j.alcohol.2019.05.006

Ana Faria, PhD, clinical nutritionist at NOVA Medical School, Lisbon, Portugal

Khemlal Nirmalkar, PhD, microbiologist at the University of Arizona