Most people are now familiar with the idea that vitamin C may help protect against and mitigate the symptoms of the common cold, although this theory is by no means universally accepted by orthodox medical opinion. But there's now evidence that supplements of vitamin E may also play a role in reducing the incidence of infection; leading some commentators to propose that combined supplements of vitamins C and E may be highly effective both as prevention and treatment.

Various recent research studies have suggested that supplementation with 200 IU of vitamin E, or 1,000 mg of vitamin C may reduce the incidence of colds by between 20 and 25%, although double-blind/placebo experiments have not always been able to confirm these results. But even if one remains sceptical about the value of vitamins E and C as weapons for combatting the common cold specifically, there's no doubt that both are highly important in ensuring the optimal health of the immune system in general, and can therefore only be of value in warding off the worst effects of this annoying, albeit usually minor illness.

And there's particularly good evidence that vitamin E functions as a general immune system booster, preserving vital red blood cells and stimulating the body's production of natural antibodies, effects which have been shown to be particularly pronounced and important in the over 60s, whose immune systems are commonly beginning to function less effectively than those of younger people.

Moreover, vitamins C and E are probably the body's two most important anti-oxidants, liquid and fat-soluble respectively, and crucial in protecting against the free radical damage to cells and tissue which left unchecked can lead to premature signs of ageing, and even the degenerative diseases which cause much of the misery associated with advancing years. So for their anti-oxidant functions alone it would be more than worthwhile to ensure an abundant supply of both of these vitamins.

When considering supplementation with vitamin E it is important to look for the tocopherol form, usually d-alpha tocopherol, which most closely replicates the naturally occurring form of the vitamin in foods such as wheatgerm, dairy produce oily fish and certain nuts and seeds.

As is well known, by far the best food sources of vitamin C are fresh fruits and vegetables, especially citrus fruits and juices. But to obtain the kind of intakes generally recommended for optimal health and the prevention of colds and other infections, which most nutritional therapists set at least 1,000 mg (1gram) per day, it is probably necessary to supplement. Fortunately, ascorbate, the manufactured form of vitamin C, is highly effective, particularly when combined with the plant bioflavonoids with which vitamin C is commonly found in nature. Such supplements are readily available.

Vitamin C appears to be non-toxic in almost any quantity which could plausibly be ingested, the only reported side effect being diarrhea, and even this has been observed only in cases where tens of grams have been consumed on a daily basis. Somewhat more caution needs to be exercised in the case of vitamin E because of its fat solubility. But even here, however, supplementary doses of several thousand IU per day ' far in excess of the normally recommended therapeutic dose of around 400 IU, appear to be very safe. The only likely contra-indication arises because of vitamin E's action as an anti-coagulant, meaning that it should not be taken before surgey or when taking any presecibed blood thinning medication.

As always in matters of nutrition, however, it is crucial to adopt a holistic approach. And both vitamins E and C will require the presence of an abundant supply of all the vitamins and minerals required by the body if they are to do their work effectively. Even orthodox opinion, therefore, whilst ordinarily inclined to cast doubt upon the therapeutic claims of nutritional therapists, commonly recommends a comprehensive multi-vitamin and multi-mineral suppplement as a valuable element in a daily regime for optimal health.