Vitamin C (ascorbic acid) has a central role in cell metabolism and helps to prevent infection and repair injury. It also aids absorption of Iron. Deficiency results in the bleeding gums and bruised, dry skin of scurvy. Extra Vitamin C may be required by the elderly, heavy smokers and drinkers, women taking the contraceptive pill, and those on other medications such as aspirin, antibiotics or steroids.
Most fruit and vegetables - preferably raw; milk, liver and kidney and new potatoes.
Powder, soluble tablets, pills. It is probably best to give a natural Vitamin C which usually comes from Acerola cherries. Synthetic ones are usually described as ascorbic acid. Natural Vitamin C preparations usually also contain bioflavonoids, thought to be necessary for its proper functioning. A form of bioflavonoids (oxyrutin) is available on prescription only for varicose veins.
Children 25-30 mg
Women 35-40 mg
Pregnant women 45-55 mg
Lactating mothers 65-70 mg
Men 35-40 mg
Maximum dose on or under 500 mg a day.
See your medical doctor if you are taking it as a supplement. It may react with drugs such as PAS, salycilates, amphetamines, anti-depressants and Warfarin. Over 50 g a day there is shown to be an increase in the excretion of Calcium, Iron and Manganese in the urine, with reduced availability of Zinc, Copper and increased uric acid and oxalic acid excretion; this may cause kidney stones in susceptible individuals. Therapeutically, Vitamin C is given in increasing doses until onset of Diarrhoea, and then cut back.. You should avoid Vitamin C supplementation if you suffer from glucose-6-dehydrogenase deficiency (an inborn error of metabolism).
Taking Vitamin C with the Pill can increase availability of oestrogen, and so convert a low contraceptive pill into a high dose one. Take 500 mg/day or less if on the Pill.
N.B. If you suddenly stop supplementation of large doses of Vitamin C, it may precipitate scurvy, so gradually cut it down over a period of a few weeks. Suddenly stopping supplementation has also been reported to cause sleeplessness, sore tongue, constipation, diarrhoea, canker sores, pain on passing urine, reduced fertility in women, and abortion in large doses (over 6 g).
* for explanation, please see Introduction to Nutritional Supplements