It's true that some of the better lab ranges don't even have an upper number. They recognize that there is no such thing as too much, but there is a big problem with too little.

The body definitely needs its protein, other B vitamins, E, iron, etc., in order to function as well as it can, and it drawns on extra resources when attempting to repair.

So, it is a very good idea to cover all safe and reasonable nutrients if not absolutely sure they are getting through in the diet. For example, if a person malabsorbs iron (likely that there is some level of malabsorption of iron if B12 is being malabsorbed), then that person (after testing of ferritin) might do well to take iron. Iron is one of those things likely to be drawn on heavily for repairs. But it should never be taken without testing.

Not everyone needs B12. Absolutely. Those with symptoms, who might benefit, are lucky that only too little is damaging.

rose