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Vitamin C- Benefits, Deficiency Symptoms And Food Sources

Alternative names :- Ascorbic acid

James Lind, a British naval surgeon, in the first clinical trial ever performed, demonstrated in the eighteenth century that citrus fruit juices prevented and cured scurvy, which was till then a scourge among sailors. The experimental study of vitamin C started with the production of scurvy in guinea pigs by Holst and Frolich. It was fortunate that they worked on guinea pig because it is now known that these animals and primates do not synthesize their own vitamin C.

SzentGyorgi isolated a substance from orange juice, cabbage, and the suprarenal glands which was identified as hexuronic acid; but its antiscorbutic properties were not apparent till Waugh and King showed that hexuronic acid was identical with vitamin C, which they had isolated from lemon juice.

Storage

The total body pool is about 2-3 g. When the body content exceeds 4 g, the excess is quickly excreted. The concentration of ascorbic acid in the tissues appears to be related to metabolic activity. It is present in descending order of concentration in the adrenal glands (55 mg per 100 g), brain, pancreas, spleen, and heart muscle.

Benefits and functions of Vitamin C

Vitamin C is a reducing substance and forms part of the tissue enzyme system concerned with oxidation and reduction. Vitamin C helps conversion of proline to hydroxyproline; the latter helps the formation of collagen. If the collagen is defective, the cells are not bound together, so that tissues such as bone matrix, teeth, and the lining of blood vessels are not properly formed.

Ascorbic acid is also necessary for the formation of osteoblasts and red blood cells, and has an antioxidant effect-it removes (scavenges) free radicals, and thus decreases the damage caused by oxidant products. Free radicals attack fats, proteins, enzymes, and DNA to produce diseases including cancer. Free radicals of oxygen and nitrogen are acted upon by ascorbic acid, an action enhanced by vitamin E.The free radicals in cigarette smoke are scavenged by ascorbate in fluids lining the respiratory tract. Smoking one cigarette consumes 0.8 mg ascorbic acid. The recommended dietary allowance for smokers is therefore 100 mg, and for non smokers, 60 mg.

Vitamin C is needed for healthy gums, to help protect against infection, and assisting with clearing up infections and is thought to enhance the immune system and help reduce cholesterol levels, high blood pressure and preventing arteriosclerosis.

Recommended dosage of Vitamin C

The recommended requirements vary from 30 to 100 mg a day. A British study showed that supplying 10 mg per day prevented clinical scurvy in adults. The committee, allowing a margin of safety, recommended 30 mg per day as the total requirement.

Deficiency symptoms of Vitamin C

Lack of Vitamin C in the daily diet leads to a disease called scurvy , a form of avitaminosis that is characterized by:

• loose teeth
• superficial bleeding
• fragility of blood vessels
• poor healing
• compromised immunity
• mild anemia

It is eventually fatal, and was a common condition among sailors and during winter. Scurvy is now very rare in industrialized countries. It should not be confused with "subclinical scurvy" or "chronic scurvy", both high-dose advocate terms for the normal human condition of blood levels lower than those typical among mammals.

Food sources of Vitamin C

Food sources of vitamin C are green leafy vegetables, berries, citrus fruits, guavas, tomatoes, melons, papayas etc.

Toxicity

Vitamin C is probably the most controversial vitamin in terms of views on the benefits and risks of high doses. For most people vitamin C has low toxicity and high intakes are tolerated. For others, however, doses above 1 g/day can cause nausea, abdominal cramps, diarrhea, and kidney stones. As vitamin C is important for iron absorption, excess vitamin C can also cause iron overload.