There are several class of vitamins each with unique chemical properties and with important biological roles to human body system. Commonly, classification of these vitamins may vary according to structural chemical composition, biological role and its solubility (fat soluble or water soluble). But whatever the biological role may it serve to human system vitamins are essential biomolecules which sustain homeostasis to organ system physiology as enzymes especially in enhancing the performance of the immune system. With this fact, it is now a norm that vitamin intake supplementation in daily basis must be considered to ensure health wellness especially those who suffer from diseases and illness; actually there are specific intake doses to each vitamin types both to water and fat soluble, if taken excessively beyond the normal dose, it will cause toxicity to organ system hence can lead to paralysis or death is some worst case. For this purpose, only selected vitamins will be viewed in terms to harmful effects that it may cause due to overdose, as well as the right dose that a normal individual must take daily; and these vitamins are C, B complex, A and E.
Vitamin C (ascorbic acid), is a water soluble types which plays numerous essential roles to human organ system especially in metabolic reactions and enhancement of the immune system. The recommended daily intake of ascorbic acid depends by age and sex; such in the United States, adult males should take 90mg per day while for adult female 75mg per day and the tolerable upper intake level for both adult male and female 2,000mg per day. The toxicity of ascorbic acid overdose may vary according to subject age, but the most common manifestation of ascorbic acid overdose and side effects are indigestion, skin rashes, headache, disturbed sleep, nausea, and vomiting if severe.
Vitamin B complex, this type is of water soluble comes into many types (B1, B2, B3, B5, B7, B9, and B12) each with unique biological function, and plays crucial role to human organ system especially in the enhancement of the immune system, nervous system, and metabolism. The recommended daily intake of B complex may vary from types, so far the established recommendation for B3 (niacin) is 35mg/day; while for B6 (pyridoxine) is 100mg/day; and B9 (folic acid) is 1mg/day. B complex toxicity may vary, but the most common manifestation is nausea, vomiting, liver toxicity, skin rashes, and blured vision.
Vitamin A (retinol) is a essential biomolecule has numerous metabolic functions which includes vision (formation of retinal), gene transcription, haematopoiesis (blood cell production), antioxidant activity, skin health and many more. The recommended daily intake of retinol may vary according to subject age and sex. For adult males, the recommended daily intake is 900µg and upper limit of 3000µg; for adult female, is 700µg and upper limit of 3000µg. While for children age 1-3, the recommended dose is 300µg and upper limit is 400µg. Overdose of retinol can cause some adverse effects to organ system depending on the amount taken excessively; among the common effects to organ system of retinol overdose is renal failure, liver toxicity, anorexia (reduced appetite), blurry vision, vomiting, hair loss, altered mental health, muscle and abdominal pain, irritability, and drying of skin; actually there are numerous manifestations of retinol overdose from acute to chronic other than stated.
Vitamin E (tocopherol) is a fat soluble vitamin, its function to the organ system generally is very essential especially in protecting the cell as an antioxidant. The recommended daily intake of tocopherol for adult male and female is 15mg/day; while depending on the age, daily recommended intake of tocopherol generally vary. In relationship, there is no findings regarding the toxicity of tocopherol overdose to human organ system; but there are several ongoing studies are now progressing towards this path to identify the effects of vitamin E overdose to human health.