ANTI-OXIDANT VITAMIN
Introduction: The antioxidant vitamin (B- carotene, vitamin- C and vitamin E) is one of the most exciting areas of nutrition research in the past few years. There has been a surge of interest in these nutrients in the past few years, as more and more studies have shown that anti-oxidants may protect against today's most prevalent degenerative diseases, including coronary heart diseases and other forms of atherosclerosis, certain cancers, cataracts rheumatoid arthritis, Parkinson’s diseases, lung diseases and perhaps the aging process itself.
The new findings on antioxidant vitamins are so compelling that they have led nutrition authorities to reexamine their views on the role of vitamins in the diet and on the criteria used to establish dietary recommendations. In short the latest observation of the researchers is- "Vitamins are no longer be regarded as mere fertilizer for depleted soil or as treatment for a few clinical deficiency syndromes, but rather as essential ingredients in many complex metabolic reactions, all of which most function at some optimal level in order to maintain health and longevity in the fragile miracle we call life."
WHAT IS OXIDATION ?
Oxidation is the act of oxidizing or state of being oxidized. Chemically it consists in the increase of positive charges on an atom or the loss of negative charges. Univalent oxidation indicates loss of one electron. Divalent oxidation indicates loss of two electrons.
WHAT IS OXIDANT ?
Oxidant is defined as the electron acceptor in an oxidation-reduction (redox) reaction. Antioxidant is defined as the electron non acceptor in an oxidation-reduction (redox) reaction.
WHAT IS ANTIOXIDANT ?
Any substance which, when present in relatively low concentrations, can delay or inhibit oxidation. Oxidation, a form of deterioration resulting from chemical reactions involving oxygen, causes the rusting of metal, the crumbling of rubber, and the rancidity of butter and fats. Accumulating scientific evidence suggests that antioxidants may also play an important role in wide variety of degenerative diseases.
Nutrients with antioxidant activity include vitamin- C, vitamin- F, the vitamin A precursor B-carotene, and several other carotenoids, some of which do not have vitamin A activity.
WHAT IS BETA CAROTENE ?
The major vitamin- A precursor found in plant foods. Unlike vitamin- A itself, Beta carotene is an effective antioxidant. Thus, it may have functions in the body independent of its vitamin activity.
The fat soluble nutrient Beta-carotene is none of the most efficient quenchers of singlet oxgen known in nature; in vitro, one molecule can deactivate about 1000 singlet oxygen molecules. Other types of carotenoids are also found in foods and in the body,and many of these also act as antioxidants.
The best food sources of Beta carotene are deep yellow/ orange vegetables (such as carrots, sweet potatoes, and winter squash), yellow / orange non citrus fruits (such as apricots and cantaloupes), and dark green leafy vegetables (such as spinach and broccoli).
WHAT ARE CAROTENOIDS ?
A group of pigments ranging in color from fed to yellow that are found in plant foods, and also found in insects, birds and other plant-eating animal species including humans. There are more than 670 naturally-occuring carotenoids in nature, many of which are biologically important in antioxidant activity. Some carotenoids are precursors of vitamin A. Beta carotene has the highest vitamin activity of any of the carotenoids and is one of the most widely distributed in nature.
WHAT IS THE RDA OF BETA CAROTENE ?
Beta Carotene has no separate RDA from that for Vitamin A. The RDA for vitamn A for Women is 4000 fU and for Men is 50001.U.
WHAT ARE THE RISKS OF BETA CAROTENE ?
Beta carotene is mainly non-toxic, because the body's own systems convey it into vitamin A only as needed.
WHAT IS VITAMIN- C ?
Ascorbic acid. This water -soluble substance is considered the most important antioxidant in extra-cellular fluids. It is also necessary for hydroxylation reactions involved in the synthesis of collagen and other important biochemical reactions. It has many intracellular activities as well. It also reinforces the antioxidant effect of vitamin- E by regenerating the active form of vitamin- E after it has reacted with a free radical-
WHAT ARE THE FOOD SORCES OF VITAMIN- C ?
Good food sources of vitamin C include citrus fruits, strawberries, cantaloupe, and a variety of vegetables including tomatoes, green leafy vegetables, and vegetables in the cabage family, such as broccoli, Brussels sprouts, and cauliflower. Some vitamin C is lost when vegetables are cooked.
WHAT IS THE RDA OF VITAMIN- C ?
The recommended Daily Allowance of Vitamin C for women and men are 60 mg. During pregnancy the RDA is 70 mg.
WHAT ARE THE BENEFITS AND RISKS OF VITAMIN- C ?
The established benefits are to prevent scurvy, loose teeth. Vitamin C may help reduce the risk of cancer and heart diseases, retards macular degeneration in the eyes of the elderly.
RISKS:
Massive daily doses- l000mg can cause diarrhea and nausea.
WHAT IS VITAMIN- E ?
Vitamin- E is the collective name for eight different tocopherols and tocotrienols. Vitamin E is the major lipid-soluble antioxidant in all cellular membranes.
WHAT IS THE RDA OF VITAMIN- E ?
The Recommended Daily Allowance of Vitamin- E for Women is 12 I.U. and for Men is 15 I.U. In pregnancy the RDA is 301.U.
WHAT ARE THE FOOD SOURCES OF VITAMIN- E ?
The best food sources of vitamin E are vegetable oils, cold pressed seed oils, and wheat germ, safflower oils and sunflower oils. Smaller amounts are in foods like peaches and prunes. However, other foods that contain smaller amounts of the vitamin contribute substantial amounts of it to the diet, because people eat them in larger amounts. These significant sources include meat/ poultry/ fish, fruits, and vegetables.
WHAT ARE THE BENEFITS AND RISKS OF VITAMIN- E ?
Vitamin E, protects the polyunsaturated fatty acids in blood lipoproteins against peroxidation. Vitamin E reacts with a variety of free radicals, particularly the peroxyl radical, and quenches singlet oxygen. Large doses of this antioxidant may protect against heart diseases and certain cancers. Studies show it could also help treat arthritis and some skin conditions. It may prevent spinal-cord damage in patients with cystic fibrosis.
RISKS:
Vitamin E is safe at 100 times the RDA.
HOW ANT1OXIDANTS WORK?
Scientists believe that compounds like vitamin A, C and E Known as antioxidants may help thwart many common diseases by taming harmful molecules known as free radicals.
1. A normal oxygen atom has four pairs of electrons. The bodies natural metabolism can rob the atom of and electron. It is now a free radical, which tries to replace the lost electron by raiding other molecules.
2. When the free radical takes an electron from a molecule in a cell wall, a new free radical is created and a chain reaction begins.
HOW DO OUR BODIES PROTECT OURSELVES AGAINST FREE RAD1CALS ?
One of the body's first lines of defense is a system of enzymes, such as glutathione peroxidase and superoxide dismutase, which react with peroxides and free radicals and inactivate them. Since certain essential minerals, including selenium, copper manganese, and zinc, are components of these protective enzymes, mineral deficiencies can hamper the body's enzymatic defenses. A second line of defense is antioxidants, which stabilize free radicals and quench singlet oxygen, a highly reactive form of oxygen. Some antioxidants, such as glutathione and uric acid, are produced by normal metabolism. Other are nutrients which can not be synthesized in the body and therefore must be obtained from the diet.
ARE FREE RADICALS ALWAYS HARMFUL?
Free radicals are not always harmful. For example, germ killing cells called phagocytes use free radicals to kill some strains of disease-causing bacteria. However, in many other instances, free radicals are more harmful than helpful. There are least 50 diseases in which a role of free radicals has been suggested.
There are at least 50 diseases in which a role of free radicals has been suggested. These are :
BRAIN:
*Parkinson's disease Neurotoxins. *Vitamin E deficiencies. *Hypertensive cerebrovascular injury *Aluminum overload. *Allergic encephalomyelitis *Potentiation of traumatic injury
EYE:
*Photic retinopathy *Ocular hemorrhage *Degenerative retinal damage. *Retinopathy *AGING
RED BLOOD CELLS:
*Falconi's aneamia *Sickle cell anemia *Favism *Malaria *Protoporphyrin photo-oxidation
CANCER:
*INFLAMMATORY- IMMUNE INJURY *Rheumatoid arthritis Golmerulonephritis *Autoimmune diseases Vasculitis (hepatitis B virus) *ALCOHOL
HEART AND CARD1OVASCULAR SYSTEM:
*Atherosclerosis. *Adriamycin cardiotoxicity. *Keshan disease (selenium deficiency) Alcohol cardiomyopathy.
KIDNEY:
Metat ion-mediated nephrotoxicity.* Aminoglycoside nephrotoxicity. * Autoimmune nephrotic syndromes
GASTROINTESTINAL TRACT:
*NSAI drug induced GI tract lesions Oral iron poisoning. *Endotoxin injury *Diabetogenic action of alloxan. halogenated hydrocarbon liver injury. Free fatty acid induced pancreatitis
LUNG:
*Bronchopulmonay dysplasia- *Mineral dust pneumoconiosis. *Bleomycin toxicity. *Hypoxia. *Cigarette smoke effect. *Emphysema.
*Adult respiratory distress syndrome. *Oxidant pollutants (Ozone, SO2, NO2)
IRON OVERLOAD:
*Nutritional deficiencies *Thalassemia and other chronic anemia with multiple blood transfusions Dietary iron overload *Idiopathic hemochromatosis *ISCHEMIA -REPERFUS1ON *Stroke/ myocardial infarction *Organ transplantation.
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