Our bodies don't make a lot of vitamins; some, like C & D, we don't make any of, so we must get them from outside sources like food or supplements (sunshine in the case of D - when that's safe, of course). Some supplements we do make naturally.

However, if there's a medical need to take some, whether we're not manufacturing them, not enough of them, aren't processing them sufficiently.... Whatever the reason, if we need more to address some particular issue (like PN) then IMO the risk of not taking them outweighs the risk of suppression.

Some people (like type 1 diabetics) are going to need supplementation for life. Our bodies make R-Lipoic Acid, and it's essential for life. I may be making enough of it to survive, but if taking more helps my PN symptoms, I'm going to take it - for however long I need to - including for life.

Everyones' dietary needs change as they age; and everyone ages/changes at different rates. I view the vitamins & supplements I take as part of my diet - like food. If I stop eating something, and become deficient in it, it doesn't matter to me if it's a vitamin, or supplement, or protein, or carbohydrates, or water, etc. I need all of these things to keep myself alive and well (as possible). :rolleyes:

Doc

There are many things in the food we eat.

I find that comments like " I only eat once a day" says to me the person is possibly lacking in many things.

For example... this came up on another post:
Glycine. This is an amino acid that is present in root veggies like beets. Glycine is necessary for many biochemical functions in the body. It provides a methyl group to methylation reactions. If you cannot synthesize it yourself, you suffer and depend on food sources.

Other important things in food are
choline (eggs)
methionine (animal protein)
sulfur containing amino acids
and there are more, but I am not going to search them
now, because of a time constraint.

So it is not just vitamins and minerals, which ARE important, but the other nutrients in foods we depend on.