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Vitamin B12 for adults 65 and over
Four micrograms a day, the same as any adult. This is the clearest case on the site where the published number is not the problem: an older adult can eat far more than 4 micrograms a day and still become deficient, because the absorption machinery fails before the diet does.
Nota de la EFSA en esta fila:el número no cambia; la absorción a menudo sí
Son valores de referencia poblacionales publicados, no un diagnóstico ni una receta. Una ingesta de referencia describe lo que cubre a un grupo sano; no puede decir su propio estado, y ninguna página puede. El embarazo, la enfermedad crónica, los medicamentos y la malabsorción cambian el cuadro: lleve esas preguntas a un médico, una matrona, un farmacéutico o un dietista.
The absorption problem, step by step
B12 in food is bound to protein. Stomach acid and pepsin have to release it; intrinsic factor made by the stomach lining has to bind it; and a specific receptor in the last part of the small intestine has to absorb the complex. Three steps, each of which can fail with age.
Atrophic gastritis — thinning of the stomach lining, with reduced acid and reduced intrinsic factor — becomes more common with age, and it breaks the first two steps. The result is food-bound B12 malabsorption: the vitamin is on the plate and does not get in. Pernicious anaemia, an autoimmune destruction of the intrinsic factor mechanism, does the same thing more completely.
Which is why free B12 often works when food does not
B12 in a supplement or in a fortified food is not bound to food protein, so it does not need the acid-and-pepsin step. That is the mechanism behind the common recommendation that older adults get part of their B12 from fortified foods or a supplement rather than relying on meat and dairy alone.
Where intrinsic factor itself is the problem, high-dose oral B12 can still work, because a small percentage crosses the gut wall by passive diffusion independently of the receptor. Injections remain the standard route in pernicious anaemia. Both are clinical decisions.
Medicines that make it more likely
Long-term metformin reduces B12 absorption and B12 levels are commonly monitored in people taking it. Long-term proton pump inhibitors and H2 blockers reduce stomach acid and so reduce the release of food-bound B12. Neither is a reason to stop a medicine on the strength of a web page — they are reasons to have B12 checked if symptoms appear.
Why catching it early matters most in this group
B12 deficiency causes a large-cell anaemia and a separate neurological syndrome: numbness and tingling in the feet and hands, unsteadiness, and cognitive and mood changes. In an older person those symptoms are easy to attribute to ageing, and the nerve damage can become permanent if the deficiency runs long enough.
It is also one of the reversible contributors to cognitive symptoms, which is why B12 is a standard test in that assessment. Unexplained tiredness, tingling, unsteadiness or memory change deserve a blood test rather than a supplement bought on a hunch.
Cómo se compara esto con cada otro grupo
| Grupo | Valor de referencia | Tipo | Nota |
|---|---|---|---|
| Hombres 19-50 | 4 µg | AI | |
| Mujeres 19-50 | 4 µg | AI | |
| Hombres 51 y más | 4 µg | AI | |
| Mujeres 51 y más | 4 µg | AI | |
| Adultos 65 y más | 4 µg | AI | el número no cambia; la absorción a menudo sí |
| Embarazo | 4.5 µg | AI | |
| Lactancia | 5 µg | AI |
Comida ordinaria frente athe 4 µgcifra paraadultos 65 y más
Lo alto de esta lista:Veal liver, 59.9 µg in a 100g ración (una ración pequeña) — 1 496% of the 4 µgcifra paraadultos 65 y más. Una ración cubre el día entero por sí sola.
| Alimento | Ración ordinaria | Por ración | Parte del día |
|---|---|---|---|
| Veal liver | una ración pequeña, 100 g | 59.9 µg | 1 496% |
| Mackerel | un filete, 120 g | 22.8 µg | 570% |
| Canned sockeye salmon | media lata, 100 g | 5.5 µg | 138% |
| Sardines | media lata, 60 g | 5.36 µg | 134% |
| Trout | un filete, 120 g | 4.93 µg | 123% |
| Salmon | un filete, 120 g | 3.66 µg | 92% |
| Liverwurst spread | en una rebanada de pan, 25 g | 3.37 µg | 84% |
| Ground beef | una ración, 120 g | 3.28 µg | 82% |
| Canned tuna | una lata pequeña, escurrida, 100 g | 2.55 µg | 64% |
| Cod | un filete, 130 g | 1.36 µg | 34% |
| Greek yogurt | un tarrito pequeño, 150 g | 1.12 µg | 28% |
| 2% milk | un vaso, 200 g | 1.06 µg | 27% |
Los tamaños de ración son raciones domésticas ordinarias elegidas para esta tabla, no raciones de referencia oficiales, y la lista corta es editorial: alimentos cotidianos de esta región en vez de las entradas más altas por 100 g de la base.Una clasificación cruda por 100 g la encabezarían hierbas secas, polvos de bebida y cereales de desayuno fortificados, lo que responde a otra pregunta.Los datos de composición son estadounidenses, así que donde la práctica de fortificación de EE. UU. difiere de la europea la fila lleva una daga y el motivo.La clasificación completa por 100 g de un nutriente la publica la sección de datos de alimentos de este sitio.
Todo el nutriente, no solo este grupo
The Vitamina B12página de ingesta de referencia lleva la tabla completa de edad y sexo, el nivel superior y lo que significa el tipo de valor.
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Fuentes:valores de referencia dietéticos de la EFSA · Reglamento (UE) n.º 1169/2011, anexo XIII · USDA FoodData Central SR Legacy (composición de alimentos) · EFSA scientific opinion on dietary reference values for cobalamin, vitamin B12 (2015) · Reglamento (UE) n.º 1169/2011, anexo XIII· comprobado2026-09-06
Preguntas frecuentes
How much vitamin B12 do older adults need?
EFSA adequate intake is 4 micrograms a day, the same at every adult age. What changes with age is absorption, not the requirement.
Why do older adults become B12 deficient on a normal diet?
Because releasing B12 from food requires stomach acid and intrinsic factor, and both decline with atrophic gastritis, which becomes commoner with age. Fortified foods and supplements bypass that step.
Should older adults take a B12 supplement?
Guidance commonly suggests getting part of the intake from fortified foods or a supplement rather than food alone, because those forms do not need the acid step. Diagnosis and treatment of an actual deficiency belong with a clinician.
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