Vitamins C Ascorbic acid functions and dosage - Food Sources and Deficiency of Vitamins C

   
Vitamin C is necessary for normal growth and development. Ascorbic acid is derived from glucose via the uronic acid pathway. The enzyme L-gulonolactone oxidase responsible for the conversion of gulonolactone to ascorbic acid is absent in primates making ascorbic acid required in the diet.

Food Sources of Vitamin C

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

Herbs that contain vitamin C include alfalfa, burdock root, cayenne, chickweed, eyebright, fennel seed, fenugreek, hops, horsetail, kelp, peppermint, mullein, nettle, oat straw, paprika, parsley, pine needle, plantain, raspberry leaf, red clover, rose hips, skullcap, violet leaves, yarrow, and yellow dock.

Functions of Vitamin C

Vitamin C promotes healthy teeth and gums, helps in the absorption of iron, aids in the maintenance of normal connective tissue, and promotes wound healing. It also helps the body's immune system. The active form of vitamin C is ascorbate acid itself. The main function of ascorbate is as a reducing agent in a number of different reactions. Vitamin C has the potential to reduce cytochromes a and c of the respiratory chain as well as molecular oxygen. Esterified vitamin C enters the bloodstream and tissues four times faster than standard forms of vitamin C because it moves into the blood cells more efficiently and also stays in the body tissues longer.

The most important reaction requiring ascorbate as a cofactor is the hydroxylation of proline residues in collagen. Vitamin C is, therefore, required for the maintenance of normal connective tissue as well as for wound healing since synthesis of connective tissue is the first event in wound tissue remodeling. Vitamin C also is necessary for bone remodeling due to the presence of collagen in the organic matrix of bones. Several other metabolic reactions require vitamin C as a cofactor. These include the catabolism of tyrosine and the synthesis of epinephrine from tyrosine and the synthesis of the bile acids. It is also believed that vitamin C is involved in the process of steroidogenesis since the adrenal cortex contains high levels of vitamin C which are depleted upon adrenocorticotropic hormone (ACTH) stimulation of the gland.

Dosage

The current recommended dietary intake for vitamin C is 90 mg for men and 75 mg for women (add an extra 35 mg for smokers). There's no good evidence that megadoses of vitamin C improve health. As the evidence continues to unfold, 200 to 300 mg of vitamin C a day appears to be a good target. This is easy to hit with a good diet and a standard multivitamin. Excellent food sources of vitamin C are citrus fruits or citrus juices, berries, green and red peppers, tomatoes, broccoli, and spinach. Many breakfast cereals are also fortified with vitamin C.

What are the deficiency symptoms of vitamin C?

Deficiency in vitamin C leads to the disease scurvy due to the role of the vitamin in the post-translational modification of collagens. Scurvy is characterized by easily bruised skin, muscle fatigue, soft swollen gums, decreased wound healing and hemorrhaging, osteoporosis, and anemia. Vitamin C is readily absorbed and so the primary cause of vitamin C deficiency is poor diet and/or an increased requirement. May lead to soft & bleeding gums, swollen or painful joints, slow-healing wounds & fractures, bruising, nosebleeds, tooth decay, loss of appetite, muscular weakness, skin hemorrhages, capillary weakness, anemia, impaired digestion.

Overdosage signs of vitamin C

Signs of an overdose may include headache, increased urination, flushed face, nausea or vomiting, lower abdominal cramps, diarrhea. May feel like the flu or common cold. Injectable forms may result in dizziness or fainting. Discontinue vitamin and consult doctor immediately. Toxicity does not normally occur, since vitamin C is water soluble and is regularly excreted by the body. Recent studies have shown, however, that excessive doses of vitamin C (many times more than the recommended amount) can lead to toxicity.

How to Store the Vitamin C?

Heat and/or moisture may alter the vitamin. Refrigeration is recommended.

Vitamin C Deficiency

Scurvy - Caused due to Vitamin C Deficiency








 

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