As the cold season is upon us, and bird flu neurosis reaches fever pitch, increasing numbers of us will be looking at ways of protecting ourselves from viral invasion. One commonly used natural remedy for the prevention and treatment of infections such as cold and flu is the herb echinacea. However, earlier this year a study published in the New England Journal of Medicine found echinacea did not protect against the common cold after all. Moreover, an editorial concluded that it is, essentially, a useless anti-infection remedy, and one consumers should leave out in the cold.
The editorial's author, Dr Wallace Sampson, a cancer specialist based in California, went even further by suggesting that natural remedies, such as echinacea, are not actually worthy of study, on the basis that they are 'implausible'. The suggestion is that there is no scientific basis for the anti-infective claims made for echinacea. However, echinacea has been shown to activate immune cells, which have anti-viral action. This herb has also been shown to boost the production of a substance called interferon, which should also help the body ward off viral infections. Dr Sampson acknowledges echinacea's immune-stimulating potential, which leaves me wondering what it is about this herb's ability to ward off infection that he finds so implausible.
My personal belief is that the methods used in the study are open to considerable question. For instance, the cold virus was instilled directly into the noses of test subjects - a technique that doesn't necessarily accurately represent how we are exposed to it and acquire colds in the real world. Also, there has been criticism from some herbalists that the dose of the type of echinacea used in the study (Echinacea angustifolia) was less than a third of the accepted effective dose.
The results must also be taken in the context of the wider evidence. In 2000, a review of dozens of studies found the majority showed echinacea had positive effects in preventing and/or treating colds, and concluded that 'overall, the results suggested that some echinacea preparations may be better than placebo'.
Dr Sampson refers to this review in a way which suggests echinacea was not found to be at all beneficial. It seems his apparent distortion of the facts may have come from an ingrained scepticism of natural medicine: the last line of his editorial describes the 'alternative-medicine movement' as an 'errant social-medical trend'. Despite such cynical comments, my experience and a significant amount of evidence suggests echinacea does have the potential to provide cold comfort.
In a recent article on salt, you stated that sodium must be multiplied by 2.5 to calculate the amount of salt. Can you explain why? Also, why do manufacturers often list the sodium, rather than salt, content of foods?
Each molecule of salt is made up of sodium and chloride. About 40 per cent of salt's weight comes from sodium, the rest from chloride. To convert an amount of sodium into the equivalent amount of salt, it must therefore be multiplied by 2.5. I do not know why manufacturers often list the sodium, rather than salt, content of foods. However, I suspect some factions in the food industry believe that at least some people will confuse sodium and salt and believe a food contains far less salt than it does. The Food Standards Agency recently mounted a campaign encouraging us to eat less salt. As well as taking a harder line on permitted salt levels in processed food, I think the government should compel manufacturers to list the salt (not sodium) content. Then there would be far less risk that people will underestimate the amount of salt they are eating.
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Unduly dry eyes are a relatively common problem which can be uncomfortable, and can make wearing of contact lenses nigh on impossible. Some natural health practitioners recognise that dry eyes may be the result of a deficiency in the so-called omega-3 fats found in oily fish and some nut and seed oils. Recently, researchers in America assessed the relationship between omega-3 intake and susceptibility to dry eyes in a group of more than 32,000 women.
This study, which was published recently in the American Journal of Clinical Nutrition, found that women with the highest levels of omega-3 fats in their diets were at significantly reduced risk of suffering from dry eyes compared to those with the lowest omega-3 intakes. The results appear to support the experience of practitioners who find that supplementation with omega-3 fats can help relieve dry eyes. Flaxseed oil, which is very rich in a type of omega-3 fat known as alpha-linolenic acid, is often used for this purpose. In practice, supplementing with 1 tablespoon of flaxseed oil (liquid flaxseed oil can be found in health food stores) each day is often effective in relieving dry eyes over time, and also usually helps to combat dry skin (which often accompanies dry eyes).