Alcohol is metabolized principally in the liver by two enzymes that act sequentially. Acetate is then metabolized by tissues outside of the liver. These individuals experience an unpleasant response to drinking alcohol, such as facial flushing, headaches, palpitations, dizziness and nausea. They also seem to have significantly higher rates of digestive tract cancers. Accordingly, ALDH2 deficiency is quantitatively the most important gene mutation potentially exposing humans to an increased risk of cancer.
Parotid glands are the main saliva-producing organs.
Located next to each ear, they are connected by a duct to the upper gingival area under the upper lip. Most people produce approximately 1.5 liters of saliva per day. Usually taken for granted until it's compromised, saliva is a clear, alkaline, semi-viscous liquid which helps both in the digestion of food as well as cleaning, helping to keep exfoliated epithelial cells, most bacteria, and food particles away from the teeth. Salaspuro's study proposes that the parotid glands are able to metabolize alcohol into acetaldehyde. Oral microflora may also produce acetaldehyde.