Even in people who do not have this genetic trait, acetaldehyde dehydrogenase is often unable to fully keep up with the production of acetaldehyde during alcohol intoxication. In some circumstances, molecular function can be completely blocked by cross-linking. Cross linking is largely responsible for age-related changes in human skin that make it inflexible, wrinkled and dry. Some of the most leathery skin you will ever see is found on alcoholics who stay outdoors a lot of the time. There are many substances that can act as cross-linking agents.
Aldehydes are one class of cross-linker, of which acetaldehyde is a member.
Acetaldehyde is used in making plastics, adhesives and fabrics. The closely related chemical formaldehyde is used in insulating foams, plywood, particle board and embalming fluid. Sulfhydryl groups interact with aldehydes to render tham incapable of forming cross links. Although this is a powerful aldehyde detoxification mechanism, it is easily overwhelmed by the relatively large amounts of alcohol that are typically consumed with alcoholic beverages as compared to the amounts of alcohol and acetaldehyde that are produced through normal metabolism. Fortunately, sulfhydryl antioxidants can easily be fortified through dietary supplementation.