Ascorbic Acid - Vitamin C

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Ascorbic acid is a simple sugar.  It is a white crystalline substance, stable, when dry, in air and light.  It is very soluble in water and easily oxidised in alkaline solution and on exposure to heat, light and traces of metals especially copper.  It is fairly stable in cold acid solution.

Physiological Action
Ascorbic acid is necessary for the proper formation of the intracellular ground substance of matrix that binds together the cells in such tissues as capillaries, bones, teeth and connective tissues.

Ascorbic acid is necessary for the formation of collagen of connective tissue.

Similarly in bones and teeth, lack of osteoid tissue and dentine prevent further development and in capillaries lack of intracellular cement in their walls can lead to rupture and thus haemorrhages.

Besides helping to produce and maintain collagen, ascorbic acid protects against infections and promotes the absorption or iron.  Like Vitamin E, ascorbic acid acts as an antioxidant for water soluble substances and is important in the production of thyroxine, the hormone that regulates the basal metabolic rate and body temperature.

The normal human body when fully saturated with the vitamin contains about 5 gms.  Perhaps 30 mgs are in the adrenal glands, 200 mgs in the extracellular fluids and the rest is distributed in varying concentrations throughout the cells of the body.

Deficiency
Most of the symptoms of scurvy can be attributed to the breakdown of collagen in the absence of ascorbic acid, loss of appetite, growth cessation, tenderness to touch, bleeding gums, loose teeth, swollen ankles and wrists, and tiny haemorrhages in the skin.

One symptom, anaemia, which is not always present in scurvy, is the vitamin's role in the absorption and utilisation of iron.  Deficiency is rare these days, but can occur in bottle fed infants if the formula is not supplemented with Vitamin C.

Dietary Sources
Citrus fruits, currants, berries and fully grown green vegetables are the richest sources.  Root vegetables and potatoes contain smaller amounts and the best animal sources are liver and other organ meats.  Ascorbic acid can be lost from foods when excess water and cooking temperatures are involved.

Recommended Minimum Dietary Intakes

• Infants 30 milligrams
• 0.6 months 25 mg
• 7-12 months 30 mg
• Children 30-50 milligrams (under 15 years: 30 mg)
• Adults 30 milligrams 16-18 years: 30 mg
• Pregnancy 60 milligrams
• Lactation 75 milligrams