Men who drank one can of alcoholic or non-alcoholic beer a day for four weeks improved the diversity of their gut microbiome, the collection of microbes that live in the intestinal tract, contradicting increasing evidence that no alcohol at all, even in small or moderate amounts, is good for you.
The pilot study, published in the Journal of Agriculture and Food Chemistry, suggested that 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, explained the authors.
The findings indicate that a once-daily beer may benefit the gut microbiome regardless of its alcohol content, though non-alcoholic beer may still be the healthier choice, reports Medscape.
“There are many myths regarding beer,” said 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 aged 23 to 58 were randomly split into two groups. One group drank 330ml of non-alcoholic 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 faecal 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 said
Beer is rich in healthy compounds called polyphenols, which reduce inflammation and oxidative stress in the gut. This creates a favourable environment for beneficial bacteria to grow in, Faria said.
Fermented foods have also been shown to boost gut microbiome diversity, Faria noted. So the micro-organisms from beer’s fermentation may contribute as well.
These findings both fit – and contradict – previous research exploring the impact of beer on the gut microbiome. One study, in 2020, found that men and women aged 21 to 53 who consumed 350ml of non-alcoholic 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, said 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.
But non-alcoholic beer appeared to boost microbial diversity in people in both studies across the board, Nirmalkar said. For now, that means non-alcoholic beer is probably 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 said, adding that many people won’t drink non-alcoholic beer because they find the taste to be “a bit weird”.
Study details
Impact of Beer and Non-alcoholic Beer Consumption on the Gut Microbiota: A Randomised, Double-Blind, Controlled Trial
Cláudia Marques, Liliana Dinis, Inês Barreiros Mota, Juliana Morais, Shámila Ismael, José B. Pereira-Leal, Joana Cardoso, Pedro Ribeiro, Helena Beato, Mafalda Resende, Christophe Espírito Santo, Ana Paula Cortez, André Rosário, Diogo Pestana, Diana Teixeira, Ana Faria, and Conceição Calhau
Published in Journal of Agriculture and Food Chemistry on 15 June 2022
Abstract
Gut microbiota modulation might constitute a mechanism mediating the effects of beer on health. In this randomised, double-blinded, two-arm parallel trial, 22 healthy men were recruited to drink 330 mL of non-alcoholic beer (0.0% v/v) or alcoholic beer (5.2% v/v) daily during a 4-week follow-up period. Blood and faecal samples were collected before and after the intervention period. Gut microbiota was analysed by 16S rRNA gene sequencing. Drinking non-alcoholic or alcoholic beer daily for 4 weeks did not increase body weight and body fat mass and did not changed significantly serum cardiometabolic biomarkers. Non-alcoholic and alcoholic beer increased gut microbiota diversity which has been associated with positive health outcomes and tended to increase faecal alkaline phosphatase activity, a marker of intestinal barrier function. These results suggest the effects of beer on gut microbiota modulation are independent of alcohol and may be mediated by beer polyphenols.
Study 2 details
Influence of moderate beer consumption on human gut microbiota and its impact on fasting glucose and β-cell function
Fernando Hernández-Quiroza, Khemlal Nirmalkara, Loan Edel Villalobos-Floresa, Selvasankar Murugesana, Yair Cruz-Narváez, Enrique Rico-Arzate, Carlos Hoyo-Vadillo, Alejandra Chavez-Carbajala, María LuisaPizano-Záratec, Jaime García-Menaa
Published in Science Direct in June 2020
Abstract
Beer is a beverage that has been consumed worldwide for thousands of years due to social, religious, and cultural reasons; it contains polyphenolic compounds as well as phenolic acids with a potential positive effect on human health. This study aimed to explore the impact of moderate beer consumption on human health and gut microbiota diversity. Three hundred fifty-five mL of non-alcoholic beer (NAB) or alcoholic beer (AB) were consumed daily by the participants for 30 days in each study. Anthropometric measures, blood samples for biochemistry, and fecal samples for microbiota analysis were collected on Day 1 and Day 30. Microbial diversity was characterized by high-throughput sequencing of 16S rDNA libraries, and data were analyzed using the QIIME pipeline. We found that NAB and AB have effects on the composition of the gut microbiota, favouring the proliferation of Bacteroidetes with respect to Firmicutes. No increase in weight, waist, and hip parameters was observed, and the liver and lipid profile values were not modified for NAB. In addition, the consumption of NAB induced a decrease in fasting blood serum glucose and an increase in functional β cells, while, on the other hand, there was an increase in blood serum glucose and a decrease in functional β cells with the consumption of AB. In general, beer consumption neither changed anthropometric values, nor affected liver function. Although the glucose values decreased with NAB or increased with AB, they remained within the normal range. Our conclusion is that moderate consumption of NAB has a positive effect on human health via supplementation of biological active polyphenol and phenolic acids, and by enrichment of the gut microbiota diversity with beneficial bacteria, while the presence of alcohol in AB interferes with this effect. More work should be done on this topic before general conclusions are drawn.
Medscape article – A Beer a Day May Boost Your Gut Microbiome (Open access)
See more from MedicalBrief archives:
No amount of alcohol is good for the heart – World Heart Federation
Beer, spirits detrimental to visceral fat and heart, but not wine – US study
Why low and alcohol free beers could be considered health drinks
No safe level of alcohol consumption — 195-nation study