By eating a wide variety of foods, the full range of thirteen vitamins (and other essential
is most likely to be obtained. Humans are omnivorous and have difficulty in managing
nutritionally on a restricted range of foods.
Vitamin supplements should be used only:
1. by individuals at high risk for nutrient deficiency, which usually means two or more of the following situations apply:
2. where there is an inborn error of metabolism which is responsive to a particular nutrient.
3. where the nutrient is useful as a medication in a concentration which is not achievable in food. These situations are few, for example, niacin (nicotinic acid) in the treatment of high blood fats (including cholesterol).
4. when there is a definite deficiency - in this situation a starting dose higher than the RDls
(Recommended Daily Intakes) may be necessary.
In most situations, the amount of vitamins used as supplements should be about the level
RDls. Unfortunately there are few such preparations available.
Vitamin supplements should be used for the shortest possible time in case long-term side effects or toxicity should arise. A problem of this type is seen with pyridoxine (vitamin B-6) where damage to the nerve fibres which relay sensation can occur.