Nutrition Noteworthy

Facial flushing is a common hypersensitivity reaction that may be observed in many Asians following low to moderate alcohol consumption. Flushing can be accompanied by other symptoms such as tachycardia, nausea, and dizziness. Recent studies have shown that this flushing reaction is due to the presence of ALDH2*2, an inactive allele for the alcohol dehydrogenase gene found in approximately 50% of Asians. Aldehyde dehydrogenase (ALDH) is an important enzyme in alcohol metabolism, and deficiency of that enzyme causes the accumulation of acetaldehyde. It is suggested that acetaldehyde mediates the flushing reaction by directly inducing mast cell release of histamine, although increased levels of catecholamines and IgE antibodies against acetaldehyde-protein adducts may play a role as well. Studies also demonstrate that carriers of the ALDH2*2 allele tend to consume lower amounts of alcohol and have lower incidences of alcohol abuse than non-carriers. These findings may explain the reduced frequency of alcoholism and alcohol consumption among Asians relative to Caucasians and other non-Asian minorities, groups in which the ALDH2*2 allele is rare.