10 Alcohol Intolerance Symptoms To Be Aware of

It feels like a bizarre time warp. You take a few sips of wine, a shot of tequila, or gulp down a beer, and your body responds with a full-out protest: instead of feeling mellow, you turn bright red, feel uncomfortably hot, and get that thumping, rapid heartbeat. What is this? A freakishly early hangover? No way — that’s not due for at least another few hours. You might chalk it up to a bad day or a sensitive stomach, but the real reason could be hiding in plain sight: alcohol intolerance.

We all know that drinking too much can leave us feeling less than stellar, but when that “ick” comes on after just a drink or two, it means there’s something deeper going on. Let's unpack the ten common symptoms of this condition and explore some ways we can manage it. 

What Causes Alcohol Intolerance?

Simply put, alcohol intolerance is the body’s adverse reaction to alcohol. While facial flushing, nausea, headaches, a stuffy nose, and itchiness are the most common symptoms, low blood pressure, high heart rate, diarrhea, hot flashes, and shortness of breath are typical as well. It's largely a genetic issue, caused by an inability to metabolize alcohol properly. The culprit? An enzyme called aldehyde dehydrogenase (ALDH), which (normally) works together with another enzyme — alcohol dehydrogenase — to metabolize alcohol in the liver.

When everything is functioning as it should, alcohol dehydrogenase breaks down alcohol into a substance called acetaldehyde — a highly reactive, toxic compound that's a main player in causing hangover symptoms and is more toxic than alcohol itself. Next, aldehyde dehydrogenase quickly steps in and converts the toxin into a harmless substance called acetic acid, a compound similar to vinegar. Once formed, acetic acid becomes a metabolic substrate: the body uses it for energy and expels the byproducts easily, without any harmful effects.

However, a problem arises when there's a deficiency or malfunction of ALDH, the enzyme involved in these conversion processes. When ALDH doesn't function properly (or when its levels are lower than normal due to genetic factors), acetaldehyde doesn't get converted into acetic acid efficiently. As a result, it accumulates in the bloodstream, leading to a range of unpleasant symptoms we identify as alcohol intolerance.

Acetaldehyde can irritate and inflame the lining of the stomach and intestines, which might exacerbate gastritis — causing nausea, vomiting, or stomach pain. In some people, an accumulation of acetaldehyde stimulates the release of histamines, causing symptoms similar to allergic reactions, such as itching, congestion, and difficulty breathing.

At elevated levels, acetaldehyde can affect the brain and nervous system, potentially causing mood changes, memory gaps, and impaired motor functions. Chronic exposure to elevated levels of acetaldehyde has even been linked to an increased risk of certain cancers, especially esophageal cancer.

A Tale of Four Booze Mishaps

Before diving deeper into alcohol intolerance, let’s discuss the differences among four alcohol-related issues that can have overlapping symptoms (many of which are linked to alcohol metabolism). They can be easy to confuse, but these issues aren’t quite identical:

Spot the Symptoms

Now, let’s explore the ten most common symptoms of alcohol intolerance, which can affect various body systems but stem from the same trigger — the inability to process alcohol effectively.

Symptom 1: Nausea 

Wrestling with nausea after just a drink or two? You might be dealing with alcohol intolerance. The body processes alcohol in the liver using enzymes that convert it to other compounds. However, the buildup of one compound, acetaldehyde, can lead to nausea in those with alcohol intolerance. 

Moreover, alcohol causes inflammation and irritation of the stomach lining. This inflammation — known as gastritis — can result in discomfort, pain, nausea, and, in severe cases, vomiting. The higher the alcohol content in a drink, the greater the likelihood and severity of nausea.

Symptom 2: Flushing of the Skin

Notice your skin getting red after a sip of Merlot? This flushing can also be one of the first signs of alcohol intolerance. Once again, it’s the result of acetaldehyde accumulation, which dilates our blood vessels. This reaction is highly prevalent in people of East Asian descent, with approximately 36% of Japanese, Chinese, and Korean populations experiencing this flush response. However, it's important to remember that alcohol intolerance isn't exclusive to any particular ethnicity — in fact, as many as 540 million people around the world have a genetic ALDH2 deficiency that results in face flushing. That’s roughly 8% of the entire population!

Facial flushing can be an uncomfortable and embarrassing reaction to alcohol, but it's also a helpful indicator of alcohol intolerance. It's the body's way of signaling that it's struggling to process alcohol. So while the alcohol-induced blush might seem like a mere cosmetic concern, it's a window into the body's internal processes and potential health risks. 

When it comes to this particular symptom, a risk that’s most concerning is the possible link to cancer of the esophagus. A 2017 study found a correlation between the two, suggesting that face flushing might be a warning sign of being at higher risk for the disease.

Symptom 3: Rapid Heartbeat. 

Ever had a racing heartbeat that comes out of nowhere after having a few sips? It could be another sign of alcohol intolerance. Once again, the main culprit is acetaldehyde, which has been linked to blood vessel dilation due to changes in heart rate. Rising acetaldehyde levels throw off the electrical signals in the heart, leading to an increased heart rate (tachycardia). Elevated acetaldehyde can also induce palpitations — the fluttering sensation that feels like skipped beats or forceful thumping.

While acetaldehyde plays a significant role in alcohol-induced tachycardia, it's not the sole player. Alcohol itself has a direct effect on the heart and blood vessels by triggering the release of stress hormones such as adrenaline, which stimulates the heart to beat faster. Additionally, dehydration caused by alcohol can concentrate the blood, making the heart work harder to pump it and resulting in an increased heart rate.

Symptom 4: Runny or Stuffy Nose. 

Some people might find their nose blocked or running after drinking alcohol. This is because alcohol can cause the blood vessels inside the nose to swell, producing more mucus and causing symptoms similar to a cold or allergic rhinitis. This symptom of alcohol intolerance is especially common with wine.

Symptom 5: Headaches. 

Headaches are one of the most reported symptoms of alcohol intolerance. Alcohol triggers blood vessels in our brain to expand, leading to an all-too-familiar pounding pain. Dehydration caused by alcohol also contributes to these headaches.

Symptom 6: Lowered Blood Pressure. 

While many people know that long-term alcohol use can raise blood pressure, in the short term — and particularly in cases of alcohol intolerance — blood pressure can actually drop. This can lead to dizziness or even fainting.

It's essential to recognize symptoms associated with a sudden drop in blood pressure after drinking. In addition to dizziness, these might include blurred vision, nausea, fatigue, and lack of concentration caused by a decrease in blood flow to the brain.

Symptom 7: Diarrhea. 

Alcohol speeds up digestion, causing the muscles in the intestines to contract more often and leading to diarrhea. Moreover, alcohol can lead to an inflammatory response in the gut, which can exacerbate the effect.

Certain types of alcohol may be more likely to cause diarrhea than others. For instance, high-sugar drinks can pull water from the intestines, leading to loose stools. Beverages high in caffeine — such as certain liqueurs or mixers — can stimulate muscle contractions in the intestines, increasing the speed of digestion.

Symptom 8: Hot Flashes. 

A sudden feeling of warmth can indicate the body's inability to process alcohol. This effect can occur due to alcohol’s vasodilatory effect, making the skin feel unusually warm for a time.

This sensation might be accompanied by sweating as the body attempts to cool itself down, and it can be followed by chills as the effects of the alcohol wear off. Certain types of alcohol —such as red wine — may be more likely to cause hot flashes than others due to chemicals that affect the body's ability to regulate temperature.

Symptom 9: Shortness of Breath. 

In some cases, alcohol intolerance can cause the body to release histamines, similar to what happens in an allergic reaction. This response can lead to inflamed airways and difficulty breathing.

If you or someone you know experiences difficulty breathing after consuming alcohol, seek immediate medical attention. This symptom should always be taken seriously, as it can quickly escalate. 

Symptom 10: Itchy Skin, Eyes, Nose, or Mouth. 

Less intense than shortness of breath, these other classic signs of an allergic reaction can occur with alcohol intolerance due to histamine release in response to certain components found in alcoholic beverages. Histamine is a compound involved in immune responses, leading to the classic symptoms of allergies: itching, redness, and swelling in the eyes, nose, and mouth. Itchiness can also be accompanied by other allergic reactions — rashes or hives, swelling (especially around the eyes, lips, or the entire face), watery eyes, sneezing, or nasal congestion.

Some people are allergic to specific ingredients found in some alcoholic beverages. For instance, wines and beers often contain sulfites, preservatives that can trigger allergy-like symptoms.

Steps for Managing Alcohol Intolerance

If you think you might have alcohol intolerance, the first step is to speak with a healthcare professional. They can provide guidance and run any necessary tests to rule out other conditions.

From there, we can take a number of steps to mitigate symptoms and navigate social situations with grace and ease.

• Reduce Alcohol Intake. The most obvious (but sometimes most challenging!) step is to reduce your alcohol intake. Every little difference counts, so cut down a bit at a time.
• Hydrate. Alternating between alcoholic drinks and water can help mitigate symptoms and reduce the overall amount of alcohol consumed.
• Choose Wisely. Some alcoholic beverages may trigger symptoms more than others. You might find, for example, that while beer sets off symptoms, wine does not. It's a process of trial and error to find out what works best for your body. Take note of reactions as they arise, and adjust your order accordingly.
• Eat First. Having food in your stomach can help slow the absorption of alcohol. Let's not drink on an empty stomach! Also, if you do choose to drink, keep in mind that eating certain foods before drinking can help us absorb and metabolize alcohol. For example, foods rich in fructose, like honey or apples, can do the trick.
• Listen to Your Body. Every body is unique, and it's vital that you listen to yours. If you notice a certain symptom flaring up, take it as a sign to slow down or call it quits for the evening.
• Get curious. Consider attending workshops or seminars that focus on understanding and managing alcohol intolerance — knowledge is power! Engaging in community forums online can also provide support, shared experiences, and new coping techniques.
• Find Support. If cutting back or quitting is difficult, remember that help is available. From support groups to therapy or online communities, there are many resources to lean on. We at Reframe would be happy to help!

Adventure Awaits

Being aware of alcohol intolerance and its symptoms lets us make informed decisions about our alcohol consumption. We're all striving to live our healthiest, happiest lives — and knowing what's going on in our bodies is a big part of that journey. 

But it’s not just about identifying what our bodies can’t handle — it’s a fresh perspective on understanding our unique constitutions. In many ways, this newfound knowledge is like receiving a personalized roadmap to a more vibrant, energized, and joyful life.

Understanding our body’s signals opens doors to new experiences, tastes, and adventures. Maybe it’s sipping on alcohol-free cocktails that surprise our palate, attending fun mocktail mixers, or even just relishing the clarity and energy of an alcohol-free evening out with friends.

The beauty of this awareness is that it empowers us to make choices that enhance our well-being, while still cherishing those festive, celebratory moments. Recognizing the signs of alcohol intolerance is not a limitation! It’s an invitation to a world of expanded possibilities. It’s all about celebrating life in a way that resonates with our truest selves.