the only cure for severe dioxin poisoning could be eating food meant for dieters. Eating snacks containing a fat substitute called Olestra can speed up the removal of dioxins and polychlorinated biphenyls ( pcb s ) from the body.

Michael MacLachlan of the Baltic Sea Research Institute near Rostock, Germany, and his colleagues are now using this treatment on two women suffering from severe dioxin poisoning.

Dioxins and pcb s are stored in body fat. Once there, it takes seven years for half the dose of the chemicals to be cleared from the body. Olestra, which the researchers believe can clear the chemicals much faster, is made by the us -based pharmaceutical firm Procter & Gamble. It tastes like fat but passes straight through the gut. Dioxins can leave the body by diffusing from body fat to fats in the blood and from there into the intestine, where they are excreted as faeces ( New Scientist , Vol 164, No 2209).

MacLachlan's team reasoned that Olestra in the gut would absorb dioxins and create steeper concentration gradient between the gut and the blood, speeding up the removal of dioxins. They tested this by feeding people three 30-gramme packets of Olestra potato chips a day and measuring the amount of dioxins and pcb s in their faeces. Depending on the particular type of dioxin or pcb , Olestra can increase excretion up to eleven times. As 40 per cent of all dioxins normally leave via the gut, MacLachlan estimates that the snacks more than double the overall rate of elimination of the toxins.

Last year, two Austrian women were hospitalised with severe pimples and blackheads of chloracne, a symptom of dioxin poisoning. One of them had the highest recorded blood levels of tcdd , the most toxic type of dioxin. Doctors tried the Olestra treatment on them. Consumption of up to 90 grammes of crisps a day, increased the rate at which the women excreted dioxin. But though chloracne in one of them improved, it remained unchanged in the patient who was more severely poisoned.