For the problem of supplement intake, it seems that Mary was having misconception of supplement intake. People often make the mistake of assuming that because supplements are sold over the counter, they are completely safe to take, even in high doses. large doses of some vitamins or minerals have been shown to be dangerous and even toxic. For example, too much vitamin C can interfere with the body’s ability to absorb copper, a metal that’s needed by the body. Too much phosphorus can inhibit the body’s absorption of calcium. The body cannot get rid of large doses of vitamins A, D, and K and these can reach toxic levels when too much is taken.