One reason doctors say that vitamin pills dont help a lot, is that there is no where to store the vitamins.
Does it get stored in fat ? it seems that fatty foods and meat provide vitamins. carnivores get vitamins…
So perhaps your beauty sleep is a real thing, as perhaps with the intestines depleated of glucose/energy, the body starts breaking down fat, releasing energy AND vitamins.
A small dose may be stored in the time before the kidney wipes it away.
However strong vitamin pills are a waste, as the kidneys just send the extra level of vitamins to the bladder before the body can make a better use of them (and before they can be stored in fat or in the liver. eg dogs liver are full of vitamin A… perhaps ready for the time they get sick by eating diseased raw meat … vitamin A shot released and so immune system on full… )