Effects of Aging

A number of structural and microscopic changes occur as the liver ages. With age, the color of the liver changes from lighter to darker brown. Its size and blood flow decrease. However, liver function test results generally remain normal.

The ability of the liver to metabolize many substances decreases with age; thus, some drugs are not inactivated as quickly in older people as they are in younger people. This puts older people at risk of receiving too high of a drug dosage (see Section 2, Chapter 14) and is one reason why their dosages must be checked carefully. Also, the liver's ability to withstand stress decreases with age; thus, substances that are toxic to the liver can cause more damage in older people than in younger people. Repair of damaged liver cells is also slower in older people than in younger people.

The production and flow of bile decrease with age. This probably has no significance but may contribute to the increased risk of gallstone formation as people age.