Vitamin requirements
Specific vitamin requirements vary widely and are influenced by the fact that many vitamins have positive or negative interactions amongst them. Vitamins can therefore never be considered in isolation but better as a whole programme. Fat soluble vitamins, for example, must be fed in correct ratios as they all compete for intestinal absorption. Water soluble vitamins are also regulators of the intermediary metabolism of protein, fats and carbohydrates (energy) and a lack of any one can increase the need for the others.