Aging Physiology & Nutritional Needs Flashcards

Which age-related change is the primary reason resting energy expenditure declines in older adults?

Answer: Loss of fat-free mass

Resting energy expenditure falls mainly because metabolically active lean tissue is lost with age.

Atrophic gastritis in older adults most directly impairs absorption of which nutrient from food?

Answer: Protein-bound vitamin B12

Low gastric acid and pepsin prevent release of B12 from food proteins, while crystalline B12 is still absorbed.

The RDA for vitamin D for adults over 70 years is:

Answer: 800 IU/day

The IOM set the RDA at 800 IU (20 mcg) per day for adults older than 70.

An 82-year-old resident rarely asks for water and has rising serum sodium. Which physiologic change best explains this?

Answer: Blunted thirst sensation

Older adults have diminished thirst perception, raising risk of hypernatremic dehydration.

Total body water in older adults compared with younger adults is generally:

Answer: Lower, due in part to loss of lean mass

Muscle holds much more water than fat, so lean tissue loss lowers total body water.

Which hormone change contributes to the 'anorexia of aging'?

Answer: Elevated basal CCK and reduced ghrelin responsiveness

Higher CCK increases satiety and reduced ghrelin response lowers hunger in older adults.

The RDA for vitamin B6 increases after age 50 to which amount for men?

Answer: 1.7 mg/day

Men over 50 need 1.7 mg/day and women over 50 need 1.5 mg/day of vitamin B6.