Vitamins are substances that are essential for normal metabolism. Humans cannot synthesize any vitamins in the body except some vitamin D in the skin and nicotamine from tryptophan. Lack of particular vitamin may lead to a specific deficiency syndrome a) Primary (inadequate diet) b)Secondary due to failure of absorption (intestinal obstruction or chronic diarrhoea or resection of intestine) or to increased metabolic need (growth, pregnancy, lactation and hyperthyroidism )
Food is the best source of vitamins and minerals. Some people think that sub-clinical vitamin deficiency causes much of chronic ill health and are liable to infections. Excess vitamins are harmful. Most of the times the doctors prescribe vitamins as supplement to drugs,which are not required.
The British Medical Council says that most people “obtain sufficient quantities of vitamins in their diet, and it is therefore unnecessary in most cases to take additional vitamins in the form of supplements”.
The American Medical assosiation issued a statement pointing out that: “ Healthy childrens and adults should obtain nutrient intakes from dietary sources.Meeting nutrient needs by choosing a variety of foods in moderation ,rather than by supplementation,reduce the potential risk for both nutrient deficiencies and nutrient excess.” The manufacturing companies make a huge profit by promoting them as health supplements ,growth promoters,memory boosters,appetizers,skin conditioners and so on.
Vitamin aUses: Vitamin A was the first fat-soluble vitamin identified (in 1913). Vitamin A comprises the preformed retinoids, plus the precursor forms, the provitamin A carotenoids . Vision, Immunity,Growth and development of tissues. Skin, hair, nails, and shields the skin from the harmful effects of the suns UV rays; and protects the membranes of brain cells.RDA for vit A- 1,000 retinol eq for man and 800 retinol eq for womenDeficiency: Night blindeness ,Xerophthalmia,keratomalacia.
Misuses Mothers administering large amounts of fish liver oils to their children in the belief that it was good for them. Misguided pregnant health enthusiastic may take enough self prescribed supplements to hazards a fetus. Toxic effects occur with prolonged high intake (in children 25000-5ooooo IU daily) Chronic signs- painful tender swellings on the long bones, Anorexia, skin lesions, hair loss, itching, hepatosplenomegaly, pappillodema,bleeding, weight loss and general malaise Overdose may also cause outer layer of skin to peel The Teratology Society advices that supplements should not exceed 8000 IU (2400 micro-grams) per day
VITAMIN C(ascorbic acid ) Works as an antioxidant ,is needed for the manufacture of neurotransmitters and cell structures, Helps preserve the elasticity of the skin and capillaries, Protects The lungs by preventing oxygen from converting into peroxides, Against bacteria and viruses, against heart and blood diseases, The body against the effects of pollutants (particularly the metals lead, mercury, and aluminum) and chemical toxins (such as formaldehyde, organic solvents, and pesticides). Reduces anxiety, and aids in restful sleep boosts the immune system, Helps wounds heal faster, helps the intestine absorb iron, Lowers blood cholesterol,. Additionally, vitamin C, a natural antihistamine, increases alertness and mental functioning, may help safeguard against and reduce the symptoms of colds and flu. Deficiency : Scurvy. RDA- 60 -70 mg.
Toxicity With too high a dose, diarrhea, dizziness, gastritis, headaches, light- headedness, nausea, and vomiting can occur, though these may be just temporary. Rare symptoms include abdominal pain and anemia. Daily dosages above 500 mg/day may deplete the level of copper in the blood of males. Women taking 2000 mg or more a day may experience fertility problems; individuals taking 2000 mg or more a day may lower the resistance of their white blood cells to fight one common form of bacteria, Those taking 3000 mg or more a day may experience reduced levels of the amino acid cysteine in the blood. Dosages above 4000 mg/day can increase kidney stone formation . Chewable vitamin C can lead to severe dental erosion
VITAMIN Dergocalciferol d2cholecalciferol D3 The best-known function of active vitamin D is to help regulate blood levels of calcium and phosphorous. Vitamin D increases absorption of these minerals from the gastrointestinal (GI) tract. In combination with parathyroid hormone, it enhances their reabsorption from the kidneys and their mobilization from bones into the blood. Vitamin D helps maintain calcium levels even if dietary intakes are not optimal. Deficiency: Rickets, Osteomalacia RDA- 200IU
Toxicity: Malaise, drowsiness, nausea, abdominal pain, thirst, constipation and loss of appetite. Long term effect – ectopic calcification anywhere in the body, renal damage, renal calculi. Prolonged use in infants can cause mental and physical retardation, kidney failure and death. Dangerous to exceed 10,000 units daily vit D in an adult more than 12 weeks. Vit D supplements should be avoided in individuals especially infants and children. Should not exceed 400 units a day.
VITAMIN B 12(cobalamin)Anti –pernicious anemia vitamin Encourages RNA and DNA synthesis in nerve cells, Its needed for the transportation and storage of folic acid. Helps stabilize the brains metabolism of carbohydrates and proteins and its synthesis of myelin in the nerves . Plays an indirect role in making choline available for the synthesis of neurotransmitters, protects against stress and fatigue (promotes the release of energy in foods), Its an essential growth factor needed for healthy brain and nerve function. RDA- 3µg for adults , 0.5 -1.5µg/day children. Deficiency- pernicious anemia, neuronal degeneration.
Toxicity Allergies to this vitamin are rare, and reactions (the symptoms for which include acne, eczema, and a swelling or crusting of skin around the lips) usually occur with injections, rather than tablets. Rare side effects consist of itchy skin, wheezing, and diarrhea. Life-threatening symptoms, usually resulting from overdose, consist of faintness (from anaphylaxis), hives, itching, and rash.
Vitamin B6 (Pyridoxine) Protects against stress and is needed by the brain for transporting and metabolizing amino acids to develop various neurotransmitters (such as norepinephrine, serotonin, and dopamine) needed for mental energy and memory. The vitamin also helps the immune system by producing antibodies and red blood cells. Necessary for the proper functioning of the thymus, spleen, and sexual organs. RDA- 2-2.2 mg/ day
TOXICITY Large dose of vit b6 cause severe nerve damage. Two B vitamins that should be avoided are vitamin B15(pangamic acid) and vitamin b17 (laetrile) Laetrile contains 6% cyanide by weight , and has caused chronic cyanide poisoning and death. Too much B-6 in the body can result in night restlessness a vivid dream recall. More than 200 mg/day cause peripheral neuropathy Doses higher than 500 mg/day may be toxic, leading to serious central nervous system problems, pain in the arms and legs, a numbness or tingling in the hands and feet, clumsiness, loss of balance, and difficulty in walking. High doses of B-6 can lead to increased susceptibility to cadmium toxicity, cause peripheral neuropathy
VITAMIN E (tocopherol)anti-sterility vitamin Vitamin E is a strong antioxidant, especially when taken in conjunction with selenium. It also strengthens the immune system; enhances the ability of brain cells to use oxygen; Increases the ability of cells to make energy; helps preserve the lung function of elderly people; And it may slow the ageing process by protecting the skin and brain cells (which have high percentages of fat compared to the rest of the bodys cells) from free radicals (as people age, their ability to absorb E decreases). RDA- 10mg for man, 8 mg for women.
Misuse No known toxicity up to 3200 IU, though it should not be taken by those who are allergic to vitamin E. It can elevate blood pressure when first taken, so those with high blood pressure or heart disease should not take more than 200 IU vitamin E may cause blood clots if taken in doses above 800 lU/day. symptoms are dizziness, and headaches. It may also cause abdominal pain, diarrhea, fever, hives, chapped lips, muscle aches, nausea, upset stomach, fatigue, weakness, and blurred vision, though these are rare. Allergies can also occur when vitamin E is used in skin preparations, but these are extremely rare.
VITAMIN K phylloquinone K1 Menaquinone k2 Menadione K3 Vitamin K helps in the activation of seven blood-clotting- factor proteins that participate in a series of reactions to form a clot that eventually stops the flow of blood. Vitamin K also participates in the activation of bone proteins, which greatly enhances their calcium-binding properties. Low levels of circulating vitamin K have been associated with low bone-mineral density. Thus, an adequate intake of vitamin K may help protect against hip fractures RDA-70-140µg/day
Misuses Prolonged consumption of megadoses of vitamin K (menadione) results in anemia, which is a reduced level of red blood cells in the bloodstream. When large doses of menadione are given to infants, they result in the deposit of pigments in the brain, nerve damage, the destruction of red blood cells (hemolysis), and death. A daily injection of 10 mg of menadione into an infant for three days can kill the child. This tragic fact was discovered during the early days of vitamin research, when newborn infants were injected with menadione to prevent a disease known as hemorrhagic disease of the newborn. Today, a different form of vitamin K is used to protect infants against this disease.
MARKETS Smith Kline Beecham advertised for Zevit : a multivitamin a long list of indications“………mood alteration, loss of libido, infertility, impotence, lethargy, depression” Abbott advertised its multivitamin with zinc as a product that “ helps promote proper growth in children, helps increase energy and vitality” Promoting vitamins as growth stimulants is a practice that is both misleading and unethical. In 1992 ,UK, three vitamin manufacturer- seven seas, Raw Power, Larkhall lab- were all prosecuted for claiming that their vitamin products could increase children ’s intelligence
Pharmax promoted its Effico Tonic as “pick-me-up” to “build up your appetite, restore your vitality, and allow you to enjoy life to full again” In most countries , the market is littered with ineffective products, with irrational combinations or formulations, or with high dose vitamins posing an un necessary threat to health and an additional financial burden.
Conclusion Do not mislead: Vitamins may be required to supplement an inadequate diet but never to complement it. Vitamins provide a profitable market for the pharmaceutical industry ,and a rent in the consumer’s wallet.
REFERENCES Multivitamins : Use or Misuse?Lt Col AS Menon*, Brig AS Narula+, Lt Col AG Mathur#MJAFI 2008; 64 : 263-267. Handbook of Vitamins and Hormones R.J. Kutsky, New York: Van Nostrand-Reinbold, 1973. http://www.healthline.com AMERICAN ACADEMY OF PEDIATRICS Committee on Nutrition Vol. 107 No. 5 May 2001 Rock Cheryl L. Multivitamin – Multimineral supplements:who use them. Am J Clin Nutr 2007;85(suppl):2775-95. Goodman and Gilman’s The Pharmacological Bas Hillman, RS. Hematopoietic agents: Growth factors, Minerals,and Vitamins: The Vitamin B Complex and Ascorbic Acid. In:Hardman JG, Limbird LE, Gilman AG, editors. Goodman and Gilman’s The Pharmacological Basis of therapeutics.10th edition.McGraw Hill, 2001.1487-517. Biochemistry iii edition by Dr.U.Satyanarayana and Dr.U.Chakrapani