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The hospital's Director of Allergy and Immunology is Dr Mimi Tang, and she says it's now clear that this policy of avoiding certain foods hasn't worked.
Mimi Tang: It seemed sensible at the time, expert groups internationally were recommending it, but it really has subsequently transpired (and this is what happens of course in research, is you discover new things that change your thinking, and this is important), but we have now understood better that to develop tolerance, one must be exposed to the antigen in the first place. So to become tolerant to a food, surely we have to have been exposed to it, otherwise how do we learn not to react to it?
Ian Townsend: This new research is revealing how complex our immune system is, and exposing how wrong we were to try to manipulate it without knowing what we were doing.
Mimi Tang: There is this shift in thinking amongst experts in the field that, you're right, maybe delaying the introduction makes it worse, not better. I take that back: delaying foods does not prevent allergy; I don't know that it makes it worse, there is no good evidence that it makes it worse, but it certainly doesn't make it better, so why would you do it?
Ian Townsend: This is a pretty big shift in thinking, and the reasons haven't been explained very well in Australia yet. Your local GP is probably reluctant to give any advice at all now.
We're talking about allergies so severe, that a small amount of nut, prawn, or egg, can cause an anaphylactic shock, or anaphylaxis. Advising people to avoid nuts was easy. Withdrawing that advice, though, is a minefield.
At Princess Margaret Hospital in Perth, Professor Susan Prescott is one of the people who's now working on the delicate process of what to tell parents they should now be doing.
Susan Prescott: I think in the next year or two, you're going to hear that the current recommendations for avoiding foods and delaying the introduction of solid foods in infancy and avoiding things like eggs, milk and so forth, and peanut in young children, is going to be changed so that we are not going to be any more recommending the delayed exposure to these foods. The earlier, maybe the better.
..... Mimi Tang: Importantly, some emerging data suggests that there might be a window of opportunity between four and seven months when you're actually very good at developing tolerance to foods. So your natural body's tendency is when you eat a food to not react to it. You learn not to react to it, you learn to be tolerant of it. And it seems that there is a window period between age four to seven months where foods introduced at that time, particularly if under the cover of breastfeeding, you are very likely to be able to be tolerant to it. It's the optimal time to develop tolerance against foods.
Then there was something in the New Scientist that I can't find.
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Just one percent of the children -- 16 kids -- developed wheat allergies. But the study revealed that children who were first exposed to cereals (wheat, barley, rye and oats) after six months were 3.8 times more likely to have developed an allergy than those who first ate cereals earlier.
The risk of wheat allergy also went up by 1.6 times if the child was exposed to rice cereal after 6 months of age and by nearly four times if a parent or sibling had asthma, eczema, or hives, the researchers found.
Of course, it could be that families who are aware of allergies because of a family history waited longer anyway, and their children may have developed the allergy regardless.
