Alcohol intolerance can cause immediate, unpleasant reactions after you drink alcohol. The most common signs and symptoms of alcohol intolerance are stuffy nose and skin flushing. Alcohol intolerance is caused by a genetic condition in which the body is unable to break down alcohol efficiently. The only way to prevent alcohol intolerance reactions is to avoid alcohol.
The commonest abnormal reaction to alcohol is seen in persons from an oriental background, who get flushing, increased heart rate, and symptoms of reduced blood pressure. This is sometimes referred to as 'oriental flushing syndrome'. Approximately 50% of Chinese, Japanese, and Koreans are deficient in ALDH, and this has been reported to be protective against the development of alcoholism.
When we consume food, with the exception of a few, is first broken down by enzymes produced by our body to become fully absorbed. Otherwise, our body may react. Alcohol, once consumed is able to enter our blood straight away; however, an enzyme produced by the liver, called Aldehyde Dehydrogenase (ALDH) breaks it down into vinegar (acetic acid).