New research shows that many older people, some vegans and types of vegetarian, have a deficiency of vitamin B12.

B12 is found mainly in animal products: meat, fish, dairy and eggs. It is necessary for a variety of functions. A shortage of it has been implicated in Alzheimer’s disease.

While solid animal products can supply plenty of the nutrient, milk is said to be the better source. Up to 60 percent is absorbed by the body.

Anyone on a diet restricting meat and animal foods should drink two glasses of milk daily — skimmed milk is fine for this purpose.

The alternative is to take a good supplement that supplies more than the stated daily requirement because of the absorption factor.