A thinning stomach lining stops prising B12 out of your food
About 6 percent of over-60s are outright deficient and roughly 20 percent sit in the marginal band. The usual cause at that age is not a meat-free diet but food-bound malabsorption.
What the study found
After 60 the problem is usually absorption, not what you eat
About 6 percent of over-60s in US and UK surveys are outright deficient, and roughly 20 percent sit in the marginal band. The usual cause at that age is not a meat-free diet but food-bound malabsorption: a thinning stomach lining stops prising B12 loose from the protein it arrives in.
The caveat · The 148 cut-off is itself disputed
The survey figures were reviewed in 2009 and predate current fortification and supplement habits. The 148 pmol/L line between deficient and marginal is itself contested, and moving it moves both percentages. The review was written to argue for fortifying flour, a stated policy position.