We’ve all been there – grabbing a drink with friends or colleagues after a long day. It’s an easy go-to for socialising, but what happens when the drinks keep flowing a little too often?
While alcohol may offer a momentary escape, researchers are starting to uncover the deeper, more troublesome effects it has on our gut health.
Dr. Ali Keshavarzian, the Director of the RUSH Center for Integrated Microbiome and Chronobiology Research in Chicago, notes that alcohol doesn’t just lead to the typical alcohol-associated diseases. It also undermines the body’s resilience, making it more vulnerable to a range of health problems.
Here’s what you should know about how alcohol can impact your gut and who is at greater risk of experiencing more serious effects.
1. Alcohol Upsets the Balance of Gut Bacteria
The first major effect alcohol has on the gut is its disruption of the microbiome, the diverse community of bacteria, viruses, and fungi that live in the intestines. These microbes usually live in harmony, working together to help the body digest food and absorb nutrients. However, heavy drinking can tip this delicate balance, favouring the growth of harmful bacteria while reducing the number of beneficial ones.
Dr. Keshavarzian explains that alcohol increases the population of pro-inflammatory bacteria, which can contribute to inflammation not only in the gut but throughout the entire body. In fact, research has linked this imbalance to serious health conditions, including obesity, type 2 diabetes, and even mental health issues like depression.
According to a study published in the Journal of Gastroenterology and Hepatology, drinking alcohol can lower the number of key beneficial bacteria, which may lead to dysbiosis, an imbalance where disease-causing bacteria take over. This is especially concerning for those with alcohol use disorder (AUD), as prolonged drinking may lead to irreversible damage to the gut microbiome.
2. Alcohol Can Damage the Gut Lining
As if disturbing the bacteria wasn’t enough, alcohol also affects the physical structure of the gut. Dr. Cynthia Hsu, an Assistant Professor in the Division of Gastroenterology at UC San Diego, explains that alcohol thins the intestinal lining, which serves as a protective barrier between your gut and the bloodstream.
Think of your gut lining as a wall built from bricks and mortar, where the bricks are the cells and the mortar holds everything together. Alcohol affects the “mortar,” causing the wall to weaken and become leaky. When this happens, harmful toxins can slip through into the bloodstream, leading to systemic inflammation and damage to other organs.
3. The Liver Also Takes a Hit
Your liver plays a vital role in processing toxins from the bloodstream, and alcohol consumption – especially when paired with a compromised gut – can overwhelm this organ. The toxins that slip through the leaky gut head straight to the liver, where they can cause long-term damage.
Alcohol-related liver disease (ARLD) is a serious condition encompassing fatty liver, alcoholic hepatitis, and cirrhosis. A study published in JAMA Open Network revealed that liver disease linked to alcohol use is one of the top causes of alcohol-related deaths, particularly among adults aged 35 to 49. The damage doesn’t stop there: the gut microbiome imbalance caused by alcohol can actually promote the growth of harmful bacteria in the liver, accelerating liver damage over time.
4. The Stomach Can Become Inflamed
Binge drinking – the kind of excessive drinking that involves five or more drinks for men or four for women – can wreak havoc on the stomach lining. This excessive alcohol intake can cause the mucus membrane that protects the stomach to become inflamed, leading to a condition called reactive gastritis.
For some, gastritis can go unnoticed, but for others, it can cause a burning or gnawing sensation in the stomach, nausea, and discomfort after eating. According to Dr. Hsu, heavy drinking can also irritate the oesophagus, leading to conditions like oesophagitis, further complicating the digestive process.
5. Even Moderate Drinking Can Have a Lasting Effect
It’s not just heavy drinkers who should worry. Even moderate alcohol consumption can have an impact, especially depending on factors like biological sex. Women for example, have less of an enzyme called alcohol dehydrogenase, which helps break down alcohol in the stomach. This means that alcohol affects women more intensely than men, even at lower levels.
For those with underlying health conditions, like fatty liver disease (now known as metabolic dysfunction–associated steatotic liver disease, or MASLD), the effects of alcohol can be more pronounced. Dr. Hsu’s research shows that even small amounts of alcohol – equivalent to just one or two drinks a day – can alter the gut microbiome of people with MASLD, making it resemble the microbiome of individuals with alcohol use disorder.
For those without underlying conditions, moderation is key. The CDC recommends no more than one drink per day for women and two drinks per day for men. These guidelines are designed to keep your gut and liver in check while allowing you to enjoy alcohol in a way that won’t cause lasting harm.
