alcohol and our microbiome

Hear from a great ambient musician, Grouper, while you read!

Chronic alcohol consumption has some really straightforward effects, such as social and direct medical issues. Today, we are going to talk about the much neglected microbiome, especially its decline in composition and diversity, caused by chronic alcohol consumption. Specifically, it can cause the gut microbiome to go from homeostasis to dysbiosis; creating toxic metabolites to digest the ingested alcohol; and destroying the intestinal lining, causing a leaky gut. For example, the Lachnospiraceae and Prevotellacea groups are affected the most, where these often-found bacteria are declining in number, causing dysbiosis.

A common toxin the body creats to digest alcohol is acetaldehyde. Alcohol is metabolized mainly by two enzymes, alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH). First, ADH metabolizes alcohol to acetaldehyde, the toxic substance we are talking about. Then, acetaldehyde is further metabolized by ALDH to another byproduct called acetate, which then is broken down into water and carbon dioxide. When acetaldehyde isn’t fully broken down, these carcinogens would stay in your gut and cause damage to the cells and tissues there. It is also worth noting that acetaldehyde is a component of tobacco, so smoking is also very unhealthy to your gut microbiome!

To investigate impacts of alcohol consumption on the microbiome leading to anxiety and depression, we need to reintroduce the gut brain axis, which is a bidirectional communication network linking your brain (nervous system) and your gut. This would connect your parts of brain where emotion is susceptible to parts of your intestine, and therefore allowing gut microbiota to influence mood and stress. Research shows microbiome imbalance due to alcoholism and decreased intestinal barrier integrity can have effects on the central nervous system leading to increases in depression and anxiety.

To explain this more clearly, we are going to use an example of liver disease caused by drinking. In liver diseases caused by alcohol use disorder, production of neuroprotective KYNA is decreased in humans with alcolhol use disorder compared to sober humans, with the production shifting to yield increase in the neurotoxic metabolite quinolinic acid (QUIN). This decreased ratio of KYNA/QUIN woudl positively correlate with fecal abundance of Faecalibacterium in our gut. Plasma levels of the KYNA produced to protect our nervous system is shown to negatively correlate with depression and alcohol craving.

To restore a healthy microbiome, prebiotic fiber supplementation after drinking would alter microbiota abundance, such as increasing serum levels of brain-derived neurotrophic factor and improved sociability. With the recent advancement is psychobiotics, young drinkers could seek a solution with coping with drinking by letting these prebiotics work on the gut brain axis mentioned before: with alterations to the gut microbiome, our brain is generally less depressive.

It is also common thing to drink lots of milk products before and after drinking. However, it is not milk that works its magic, but any food with high fat, protein or even carbohydrates, with could delay your stomach emptying, and therefore slowing down the absorption of alcohol. Some British people would deal with hangovers with a big breakfast with eggs, as eggs contain cysteine that could reduce nausea, headache, stress and anxiety; which could prevent further drinking. And from experience, if your face turns red, please stop drinking, it shows your digestive system is lacking enzymes to reduce alcohol and it could be stuck in your liver, putting more pressure on organs.