Final answer:
An increased body water is not a common change in body composition of healthy older adults. Aging typically involves a decrease in lean body mass, an increase in redistributed fatty tissue, and decreased bone mineral mass.
Step-by-step explanation:
The question asks which of the following is not a common change in the body composition of healthy older adults. The options given are increased body water, decreased bone mineral mass, decreased lean body mass, and redistributed fatty tissue. It is well-documented that as part of the aging process, there tends to be a decrease in lean body mass, an increase in fat mass (with a redistribution of this fatty tissue), and a decrease in bone mineral mass, leading to conditions like osteoporosis. However, an increase in body water is not a common change associated with aging. Actually, the total body water tends to decrease, which can affect the distribution of water-soluble medications in older people.
Therefore, the correct answer to the student's question is option 1: Increased body water. This does not commonly occur in healthy older adults as a change in body composition.