While nutritional medicine has enjoyed growing acceptance among doctors over the last decade or so, factions in the medical establishment remain sceptical about the health benefits of naturally oriented approaches. In 'Detox Diets Provide Empty Promises', an article in last month's Food Technology, a doctor and a scientist from the US take a cynical view of the notion that detox diets can enhance health and well-being. They argue that such diets are irrational and unscientific, and leave us with the impression that those touting such internal cleansing methods are engaged in what amounts to a dirty business.
While there is a lack of scientific evidence for detox diets, this comes as no surprise, as such diets have not been subjected to formal study. They are based on the principle that the body can suffer from excesses of internal pollution, the sources of which include the breakdown products of food and toxins that are ingested, inhaled and absorbed through the skin. The conventional view, and the stance taken in the Food Technology article, is that within hours of gaining access to the body, toxic substances are neutralised through the lungs, liver and kidneys.
This theory assumes that the body has unlimited capacity to cope with pollutants. Yet if this were the case, we could all quaff arsenic. The fact is that there is potential for levels of toxic substances to exceed the body's ability to deal with them. This opens up the possibility that we may harbour levels of toxic substances which compromise well-being. In practice, excesses of internal toxicity seem to manifest as issues such as fatigue, spots and bad breath.
Diets designed to deal with toxicity emphasise nutritious foods believed to be easily assimilated by the body (eg fruit and vegetables, preferably organic), coupled with plenty of water. Over the years, I have heard countless glowing reports of the well-being improvements such diets seem to induce. Curiously, the detox-diet detractors writing in Food Technology do not dispute these benefits, but attempt to explain them through alternative mechanisms including improved hydration and a reduced intake of alcohol and caffeine - all things that would be expected to assist the detoxification process.
Also, while they condemn detox diets as unscientific, they do not quote one single piece of evidence from the scientific literature that supports their views. One wonders where the science is in that.
While a number of nutritional factors is likely to be fuelling the rise in childhood obesity in the UK, one specific foodstuff that has been singled out for attention with respect to this is soft drinks. Previous research has found, for instance, that for each serving of soft drink consumed by a child each day, risk of obesity increases by a whopping 60 per cent.
Also, evidence suggests that even modest reductions in soft-drink consumption will reduce the risk of obesity considerably. This and other evidence was recently reviewed in the Journal of Pediatrics in America. Its negative conclusions about the likely impact soft drinks have on childhood weight have been followed by renewed calls for stricter policing of the consumption of these drinks by youngsters.
One potentially effective way to help curb soft-drink consumption by children would be to ban such beverages on school premises. Those who feel strongly about this issue may feel sufficiently motivated to raise this matter with their children's schools, local education authorities and MPs.
Two years ago I started exercising for a few hours, three times a week. But now I seem more prone to catching colds. Why is this, and what can I do about it?
Studies show that exercise can suppress immune function and therefore increase susceptibility to infection. Prolonged and/ or strenuous exercise is more likely to do this, so it may help to exercise more frequently for a shorter period of time and at lower intensity.
Avoid exercise during an infection, as the transient suppression of the immune system that exercise induces is likely to prolong infection. Immune function is dependent on nutrients including iron, zinc, vitamins A and E, and some B vitamins. I'm not aware of research that has looked at the effects of nutritional supplementation on immune function in those who exercise. Yet there is some evidence that taking a multivitamin and mineral each day may be useful for reducing infection risk. Also, my experience in practice is that nutritional supplementation in those engaged in regular, strenuous exercise does seem to help keep them infection-free.
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