You love beer, but does your microbiome? Here’s what you need to know (and how to benefit from your pint).
Beer. It’s a well-loved beverage - it has its own celebratory day (June 15th in case you were wondering) and there’s even a word to describe the fear of an empty beer glass - cenosillicaphobia. Try saying that after a beer or two.
Thought to have originated in Mesopotamia (an ancient region in the Mediterranean) beer is one of, if not the oldest recipe known to man, and was used as a form of currency by the Ancient Egyptians. Amusingly, beer was once favoured over water, since drinking water was often contaminated and considered unsafe.
Beer and microbes
Beer is made from cereal grains - usually barley - plus water, hops (a flower which provides stability and flavour) and yeast - a type of fungi. During the beer making process, the yeasts consume the sugars in the grain, transforming them into alcohol and carbon dioxide - the former is responsible for the intoxicating effects of beer, and the latter is what makes beer bubbly.
This process - yeasts transforming sugars into alcohol and carbon dioxide - is a type of fermentation. If you’re interested in gut health you’ve probably heard that fermented foods have potential benefits for your gut. So does this mean beer is good for your gut?
Alcohol and your gut
When considering the effects of beer on gut health, we need to consider two things - both its alcoholic and non-alcoholic components.
First, let’s consider the alcoholic part. Alcohol affects the activity of the muscles in your gut, increasing motility (movement), which can trigger loose stools. This is in part what’s responsible for the phenomenon known as DADS - or day after drinking stools.
Some types of alcohol (including beer) also stimulate acid production in the stomach, leading to heartburn. Drinking lots of alcohol affects gut permeability too - in short it can cause the ‘doormen’ lining your gut to become a little lax. Though only temporary, this may affect immune function. Then there’s your ‘biome. Studies show that drinking lots of alcohol can suppress the levels of beneficial bacteria in your gut, which isn’t a good thing, as a diverse mix of beneficial bacteria seems important for your overall health.
It’s also worth bearing in mind the food that typically accompanies a few pints. An after-work beer which escalates into a last orders session can easily transform a well-intentioned healthy stir fry into a burger and fries on the way home - which offers little in the way of nutrition for your gut bugs.
Hands up for polyphenols
Happily, the non-alcoholic components of beer are more favourable. Beer is a source of polyphenols, naturally occurring compounds in plant foods that feed the beneficial microbes in your gut. The levels of polyphenols are determined by the type of grain used and the production method, but some researchers think that artisan and darker beers may have more benefits, as they contain higher levels of polyphenols.
In a study published earlier this year, researchers looked at the impact of drinking beer on gut microbiota in healthy volunteers. For 30 days, participants drank either 355ml (a small bottle) of alcoholic or non-alcoholic beer daily, with blood and faecal samples collected at day 1 and day 30. Results showed that the non-alcoholic beer resulted in an increase in the numbers of beneficial bacteria in the gut, which was not seen with the alcoholic beer. The results suggest that whilst beer polyphenols seem to have a positive impact on gut bacteria, the presence of alcohol seems to interfere with the effects.
More recently, British researchers looking into the effects of alcohol on the gut microbiome reported that whilst red wine drinkers have more diverse microbiomes, beer wasn’t found to have a significant effect either way.
The take home
So, what can we learn? Thanks to its polyphenol content, beer may have some positive effects on the ‘biome - but we need more research to learn if the alcoholic components counteract the potential benefits on the ecosystem in your gut.
Until then, moderation is your best bet - especially when we consider the broader effects of alcohol on gut health. What is moderation you ask? Good question. In the UK, low risk drinking is termed as 14 units a week - one pint of 4% beer being equivalent to about 2.3 units. This means the recommended maximum is equivalent to 6 pints per week. Spreading these out and opting for several drink-free days a week is also recommended, as is teaming your beer with food, rather than drinking on an empty stomach.
And, if it’s polyphenols you’re looking for, choose darker or artisan beers, opt for a non-alcoholic beer, or switch up your beer for a glass of red wine to get maximum benefits. Cheers!
References
Hernández-Quiroz, F., Nirmalkar, K., Villalobos-Flores, L. E., Murugesan, S., Cruz-Narváez, Y., Rico-Arzate, E., … García-Mena, J. (2019). Influence of moderate beer consumption on human gut microbiota and its impact on fasting glucose and β-cell function. Alcohol. https://doi.org/10.1016/j.alcohol.2019.05.006
Engen, P. A., Green, S. J., Voigt, R. M., Forsyth, C. B., & Keshavarzian, A. (2015). The gastrointestinal microbiome: Alcohol effects on the composition of intestinal microbiota. Alcohol Research: Current Reviews, 37(2).
Purohit, V., Bode, J. C., Bode, C., Brenner, D. A., Choudhry, M. A., Hamilton, F., … Turner, J. R. (2008). Alcohol, intestinal bacterial growth, intestinal permeability to endotoxin, and medical consequences: Summary of a symposium. Alcohol, 42(5), 349–361. https://doi.org/10.1016/j.alcohol.2008.03.131
Kings College London. (2019). Red wine benefits linked to better gut health; study finds. Retrieved November 4, 2019, from https://www.kcl.ac.uk/news/red-wine-benefits-linked-to-better-gut-health-study-finds
