Eating in Later Life

Story

Connected to · 4

regulates · 4

Vitamin B12
With age the stomach lining often wastes away and makes less acid, so the B12 in food cannot be stripped free: a review reports that more than 20% of older people are short of B12, and in more than six cases in ten it was eaten but never released from the food. Long-term use of acid-reducing medicines is also linked to low B12.
Sarcopenia
Older people's appetite shrinks and they eat less, while their muscle responds less to the protein in a meal, which is called anabolic resistance: in pooled data, older men needed about 0.40 g of protein per kilogram of body weight in a meal for muscle building to peak, against about 0.24 g in young men. So older people need enough protein, spread across every meal.
Water & Electrolytes
Thirst comes later and weaker in older people: after 24 hours without water, healthy older men had more concentrated blood and higher antidiuretic hormone, yet felt less thirsty, drank less and could not concentrate their urine as well as younger men. So older people should drink at set times rather than wait for thirst.
Vitamin D
The skin's raw material for vitamin D declines with age: in skin samples removed during surgery, skin from people in their late 70s and early 80s made less than half as much vitamin D precursor under the same ultraviolet light as skin from children and young people. Older people also go out less and show less skin, so they run short more easily.

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Why appetite shrinks with age

THE SHORT ANSWER

Part of a shrinking appetite in older people is physical: the stomach empties more slowly, the fullness signal CCK runs higher, energy needs fall, and lost weight does not easily come back by itself.

WHAT IT MEANS FOR YOU

After an illness or a few weeks of poor appetite, check whether the weight comes back.
Eating and drinking very little and suddenly confused or hard to wake: call emergency services now.

EVIDENCEGUIDE 2 · REVIEW 2 · RCT 1 · OPEN 2

READ THE ORIGINAL

Older people eat less partly because of what happens inside the body: the signals of fullness arrive earlier and louder. It is not just that their taste has become fussy. This shrinking of appetite and intake is called the anorexia of aging. It is common, but it is not an unavoidable part of getting old (Landi 2016).

At least three things change. The first is slower stomach emptying: food leaves an older stomach more slowly, and the slower it leaves, the less hungry a person feels after a meal (Clarkston 1997). The second is a stronger fullness signal: when food reaches the small intestine, the gut wall releases a fullness signal called cholecystokinin (CCK), and healthy older adults have more CCK in their blood than younger adults and feel less hungry (Johnson 2020). The third is a smaller energy need: with less muscle, the body simply burns less (Volkert 2022).

The body's ability to correct itself also weakens. In a small study, men first ate less for three weeks and then ate freely. The younger men ate more on their own and regained the weight; the older men did not (Roberts 1994). So weight lost during an illness or a few weeks of poor appetite may not come back by itself in an older person.

If an older person is eating and drinking very little and suddenly becomes confused or hard to wake, call emergency services now. The chapter When an older parent needs a doctor lists every situation that needs a doctor.

Educational content, not medical advice — consult a clinician.

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Eating in Later Life

Story

Connected to · 4

regulates · 4

Vitamin B12
With age the stomach lining often wastes away and makes less acid, so the B12 in food cannot be stripped free: a review reports that more than 20% of older people are short of B12, and in more than six cases in ten it was eaten but never released from the food. Long-term use of acid-reducing medicines is also linked to low B12.
Sarcopenia
Older people's appetite shrinks and they eat less, while their muscle responds less to the protein in a meal, which is called anabolic resistance: in pooled data, older men needed about 0.40 g of protein per kilogram of body weight in a meal for muscle building to peak, against about 0.24 g in young men. So older people need enough protein, spread across every meal.
Water & Electrolytes
Thirst comes later and weaker in older people: after 24 hours without water, healthy older men had more concentrated blood and higher antidiuretic hormone, yet felt less thirsty, drank less and could not concentrate their urine as well as younger men. So older people should drink at set times rather than wait for thirst.
Vitamin D
The skin's raw material for vitamin D declines with age: in skin samples removed during surgery, skin from people in their late 70s and early 80s made less than half as much vitamin D precursor under the same ultraviolet light as skin from children and young people. Older people also go out less and show less skin, so they run short more easily.

Read full story

Stop 1/7

Why appetite shrinks with age

THE SHORT ANSWER

Part of a shrinking appetite in older people is physical: the stomach empties more slowly, the fullness signal CCK runs higher, energy needs fall, and lost weight does not easily come back by itself.

WHAT IT MEANS FOR YOU

After an illness or a few weeks of poor appetite, check whether the weight comes back.
Eating and drinking very little and suddenly confused or hard to wake: call emergency services now.

EVIDENCEGUIDE 2 · REVIEW 2 · RCT 1 · OPEN 2

READ THE ORIGINAL

Older people eat less partly because of what happens inside the body: the signals of fullness arrive earlier and louder. It is not just that their taste has become fussy. This shrinking of appetite and intake is called the anorexia of aging. It is common, but it is not an unavoidable part of getting old (Landi 2016).

At least three things change. The first is slower stomach emptying: food leaves an older stomach more slowly, and the slower it leaves, the less hungry a person feels after a meal (Clarkston 1997). The second is a stronger fullness signal: when food reaches the small intestine, the gut wall releases a fullness signal called cholecystokinin (CCK), and healthy older adults have more CCK in their blood than younger adults and feel less hungry (Johnson 2020). The third is a smaller energy need: with less muscle, the body simply burns less (Volkert 2022).

The body's ability to correct itself also weakens. In a small study, men first ate less for three weeks and then ate freely. The younger men ate more on their own and regained the weight; the older men did not (Roberts 1994). So weight lost during an illness or a few weeks of poor appetite may not come back by itself in an older person.

If an older person is eating and drinking very little and suddenly becomes confused or hard to wake, call emergency services now. The chapter When an older parent needs a doctor lists every situation that needs a doctor.

Educational content, not medical advice — consult a clinician.