She notes that the "deficiency is especially common in older adults ... or breastfeeding women. "Unlike some of the other vitamins," advises Mason, "vitamin B12 is felt to be exceedingly safe ...

Our need for particular nutrients changes as we get older, so it’s crucial ... A good multivitamin for women over 60 should contain vitamins B12, D, and E, as well as calcium, magnesium, and ...