Text VII. Control of Colds

Many attempts have been made to prove that vitamin C (ascorbic acid) can prevent or abort colds. Many of the experiments were poorly controlled and do not stand up to scientific scrutiny. However, a few well-designed and well-conducted experiments have been done, using doses of ascorbic acid up to 3 or even 4 g per day. Most of these studies have given negative or, in a few case, marginally positive results; the latter have usually shown reduced severity and duration of colds rather than a reduction in their number, but positive results have not always been confirmed on further testing. However, ascorbic acid in moderate doses is probably relatively harmless, though gastro-intestinal symptoms (nausea and diarrhea) may occur; prolonged high dosages increase urinary excretion of oxalate and may encourage the formation of calculi. A detailed evaluation of the evidence on the efficacy and toxicity of ascorbic acid was undertaken by Dykes and Meier (1975).

Based on present knowledge of the epidemiology and spread of rhinovirus infection a few common-sense prophylactic measures can be suggested. Bronchitis and asthmatic in particular should if possible avoid close and prolonged contact with people in the acute stages of colds, particularly young children. If the manual route of infection is assumed to be significant, frequent washing of the hands and avoidance of fingering the conjuctiva or the nostril may help to reduce the rates of infection. On the other hand there is no evidence that colds are acquired by traveling on public transport.

25. Read text VIII and give the abstract of it: