Not a nutty idea
It may be possible to reduce the sensitivity of those allergic to peanuts
“MAY contain nuts” appears so often in the ingredients lists of processed foods that it might seem to most people to have the warning value of the boy who cried “wolf” in Aesop’s fable. Allergy to nuts, particularly to peanuts (strictly legumes, not nuts), is not, however, to be treated lightly. The anaphylactic shock provoked is always nasty and can, if the swelling obstructs someone’s airways, kill.
Youngsters who have peanut allergy, and their parents, may therefore be interested in a study by Andrew Clark and Pamela Ewan of Cambridge University Hospitals, which is reported in this week’s Lancet. This suggests that the immune system (whose adverse reaction causes anaphylaxis) can be trained to become less sensitive to peanuts, to the point where accidental exposure to small amounts of them will cause no harm.
The two researchers made this discovery by recruiting 100 peanut-sensitive youngsters aged between seven and 16 and asking half of them to eat increasing amounts of peanut protein daily, up to 800mg (roughly equivalent to five peanuts) for 26 weeks, and the other half to continue avoiding foods containing them for the same period. That done, they were tested to see how much peanut protein they could tolerate. Those in the second group were then asked to behave as the first group had done for another 26 weeks, and tested again.
In the first group, 84% of participants could eventually tolerate nibbling the equivalent of five peanuts a day. No member of the control group could do likewise until after receiving similar treatment, when 91% could. In addition, 62% of the first group were unaffected by ingesting a single 1,400mg dose of peanut protein—a large amount, unlikely to be scoffed by accident. And 54% of the second group were able to do so once they, too, had undergone the experimental regimen.
This is not, the researchers emphasise, an experiment that anyone should attempt at home. Even under medical supervision adverse reactions occurred. Most were mild, but one person had to be treated twice with adrenalin—and, not surprisingly, then withdrew from the study. But if this approach can be turned into a medical protocol (and particularly if it proves possible to work out in advance who is likely to benefit from it), it might prove to be a way to reduce the number of those who have to pussyfoot through life’s more exotic menus, and actually do need to worry about the ingredient warnings which inspire others to joke.
This article appeared in the Science & technology section of the print edition under the headline "Not a nutty idea"
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