The New Straits Times, September 11,1995
Q: I notice that preparations containing large doses of vitamins are easily available without prescription. Are these chemicals really free of toxic effects?
A: Vitamins have been claimed to improve health and general well being. However, vitamin deficiency is essentially rare in individuals who maintain a balanced diet.
The use of vitamins as prophylactics against certain types of disease such as arthritis, cancer, or even mental illness has been propagated by many. Yet, scientific data to prove any significant effect of vitamins in these conditions is still lacking. In fact, the taking of vitamins in excessive doses (megavitamins) can produce toxicity. However, different megavitamins give different toxic effects. For example, a single dose of one million international unit or IU of vitamin A (recommended dose is about 3,000 IU) can cause headache, vomiting, irritability and peeling of the skin. Too much of vitamin D (50,000 IU as opposed to the recommended daily allowance of 400 IU), taken over a period of many months to year, may induce weakness and bone pain.
Some poison centres in the United states have reported that vitamin toxicity is more prevalent in infants and children. This is mainly due to acute accidental poisoning by unsuspecting toddlers. In developing countries, parents overzealousness in dishing megavitamin preparations to their children appears to be the main source of toxicity.
The other group of individuals susceptible to vitamin toxicity syndromes is the elderly. These geriatrics tend to consume the readily available vitamin preparations without proper medical supervision. Excessive intake of vitamin A (e.g. 150,000 IU daily) over a period of a few years many induce liver damage.
Thus, these words of Paracelsus, the Father of Modern Toxicology, aptly describe the seemingly ironic effects of vitamins.
