Vitamins 101: What Every Adult Should Take Daily

The supplement market is worth more than the evidence behind most of it. That does not mean nothing works — it means the useful list is shorter than the shelf.

The short list

Vitamin D is the one with the strongest case for most adults, particularly anyone north of about 37 degrees latitude between October and March. The body makes it from sunlight it is not getting. Folate matters for anyone who might become pregnant, and it matters before conception rather than after, which is the part that gets missed. B12 matters for anyone eating little or no animal product, and deficiency is slow, quiet and neurological — not something to find out about late.

The long list, briefly

Iron only if a blood test says so. Calcium only if the diet is short of it. A multivitamin does no harm and, for most people eating reasonably, does very little good either.

What to check on a label

The amount per serving and the serving size, in that order. A bottle promising 1000% of a daily value is telling you it contains something your body will excrete.