It's long been known that humans can overdose on calcium (mineral) and fat soluble vitamins (A, D, E, K) and some members of the water soluble B group of vitamins. Fat soluble vitamins tend to accumulate in human bodies if taken in high doses, which is difficult from normal food / diet, but much easier when taking supplements. If you take too much vitamin C, it comes out in urine, so can actually be used to increase acidity of urine, and thus treat / less chance of recurrence of urinary tract infections. Also worth noting that most people get most of their vitamin D from sunlight, and only a small proportion from food / supplements. It depends on colour of skin and location (relative to equator / poles).
There are several recorded incidents of polar explorers suffering ill health after running out of conventional food and eating only liver from huskies, polar bears, seals etc - whatever they could kill. Liver was the most palatable piece of the body, although it's strange that they would eat no muscle meat. Liver is a rich source of fat soluble vitamin A.
