Can vitamins cause toxicity?

Vitamins are a group of unrelated chemical substances that are essential in small amounts for the regulation of normal metabolism, growth, and function of the human body. Not all of the vitamins can be synthesized in the body, and therefore, some vitamins must be obtained from an external source, such as a proper wellbalanced diet or dietary supplements.

Vitamins become a pharmacological concern when there is an imbalance in the body’s vitamin supply. Deficiency diseases can result from insufficient vitamin ingestion, irregular absorption, or impaired metabolic use of these nutrients. The ingestion or administration of excessive quantities of vitamins, also known as hypervitaminosis, may result in toxicity.

DEFICIENCY DISEASES

Medical personnel who work in affluent areas are unlikely to see large numbers of people with vitamin deficiency diseases. However, certain groups of the population are particularly at risk, such as low-income families and chronically ill patients.

The classic symptoms of any vitamin deficiency disease as observed in laboratory animals are often blurred in humans.The clinical picture is often complicated by deficiencies of other vitamins,minerals,calories, and protein and by infections and parasite infestations, which usually accompany longstanding malnutrition.

TOXIC EFFECTS

Toxic effects have been observed when large dosages of some vitamins are ingested. Generally the water-solublevitamins are less toxic, since excess quantities are usually excreted in the urine. Excessive amounts of fatsoluble vitamins, however, are stored in the body, which makes toxic levels of these vitamins easier to obtain.

NB:

Vitamins are usually classified as either fat soluble (vitamins A,D, E, and K) or water soluble (vitamins B and C). The fat-soluble vitamins are generally metabolized slowly and are stored in the liver. In contrast, the watersoluble vitamins are rapidly metabolized and are readily excreted in the urine.