Many people feel sick or unwell after drinking wine, even in moderate amounts. These unpleasant symptoms are often incorrectly dismissed as a simple hangover or mild allergic reaction. The symptoms are not solely due to ethanol, the alcohol itself, but stem from the interaction between various naturally occurring compounds in the wine and specific sensitivities within the drinker’s body. Understanding why wine causes sickness requires looking beyond the alcohol content to the other biological compounds introduced during the winemaking process. These reactions often represent an intolerance or metabolic failure related to how the body processes these unique substances.
Primary Chemical Culprits: Histamines and Sulfites
Two chemical compounds frequently discussed as causes of adverse reactions are histamines and sulfites, each provoking distinct symptoms. Histamines are biogenic amines that occur naturally in wine, particularly in red varieties, as a byproduct of fermentation. For individuals with a histamine intolerance, their body lacks sufficient diamine oxidase (DAO), the enzyme required to break down ingested histamine. The resulting buildup of histamine in the bloodstream can trigger symptoms that resemble a mild allergy, such as facial flushing, a runny nose, nasal congestion, and headaches.
Sulfites are used by winemakers as preservatives and antioxidants to prevent spoilage. While a true sulfite allergy is extremely rare, sulfite sensitivity can cause issues, especially for people with pre-existing conditions like asthma. When sensitive individuals consume sulfites, they may experience hives, digestive problems, or a worsening of respiratory symptoms like wheezing.
The Body’s Response: Acetaldehyde and Alcohol Intolerance
A more severe and rapid reaction to wine can be traced back to the body’s inability to properly metabolize ethanol, the main alcohol component. When the liver processes ethanol, it is first converted into a highly toxic compound called acetaldehyde by the enzyme alcohol dehydrogenase (ADH). Normally, a second enzyme, aldehyde dehydrogenase 2 (ALDH2), rapidly converts this acetaldehyde into harmless acetate, which is then eliminated.
However, a genetic variation, most common in people of East Asian descent, leads to a dysfunctional ALDH2 enzyme. This ALDH2 deficiency causes acetaldehyde to accumulate quickly in the body, leading to a toxic buildup and the immediate onset of severe symptoms. This condition, often called “Asian flush syndrome,” results in intense facial flushing, severe nausea, dizziness, and heart palpitations, even after consuming a small amount of wine.
Polyphenols and Migraine Triggers: Tannins and Tyramine
For those who primarily experience headaches or migraines after drinking wine, the culprits may be specific polyphenols and another type of biogenic amine. Tannins are complex polyphenols derived from grape skins, seeds, and the oak barrels used for aging, and they impart the characteristic astringent, drying sensation in the mouth. These compounds have been implicated in triggering headaches, possibly by interfering with the body’s serotonin levels.
Another compound linked to severe headaches is tyramine, which is also a biogenic amine found in fermented foods, including red wine. Tyramine is a known trigger for migraines in sensitive people, especially those who take certain medications that inhibit the enzyme monoamine oxidase (MAO). The mechanism of tyramine-induced headaches is distinct from histamine, focusing more on its role as a vasoconstrictor and its effect on blood pressure regulation in susceptible individuals.
Identifying Your Specific Wine Sensitivity
Determining which compound is causing your discomfort is the first step toward finding a solution, as different triggers produce different symptomatic patterns. If your symptoms include rapid facial flushing, severe nausea, or an accelerated heart rate after just a few sips, your body is likely struggling with acetaldehyde due to an ALDH2 enzyme deficiency. This is a metabolic issue, not a sensitivity to the wine’s ingredients.
If your reaction is characterized by allergy-like symptoms such as nasal congestion, sneezing, or hives, you may have an intolerance to histamines or sulfites. If your primary complaint is a delayed, intense headache or a full-blown migraine, the trigger is more likely the tannins or tyramine in the wine. These compounds are often more concentrated in heavily oaked or aged red wines.