Paula Goodyer July 03, 2012
What to put in the lunch box? ... conflicting allergy advice has parents bewildered. Photo: Marina Oliphant
Hands up: what's the most common food allergy in children? If (like me) you guessed peanuts, you'd be wrong. Egg allergy is the number one food allergy, says Associate Professor Debbie Palmer of the School of Paediatrics and Child Health at the University of Western Australia, but it has an advantage that peanuts don't – it's generally short lived. While egg allergies often disappear by school age, peanut allergy can be forever – only around 20 per cent of children grow out of it.
With food allergy on the rise – it's three times more common than it was a generation ago - researchers are looking for ways to stem the tide. Until recently the advice on preventing food allergy has been to avoid giving babies potentially allergenic foods early. Now the pendulum is swinging the other way and a strong contender for allergy protection is introducing babies earlier rather than later to foods that cause most childhood food allergy - eggs, cow's milk, peanuts, tree nuts, soy, wheat, fish and shellfish, says Palmer.
With eggs, for instance, the advice from the 2003 guidelines from Australia's National Health and Medical Research Council and still used by some health professionals, is to introduce yolk at eight months and egg white at 12 months. But some studies have found that introducing egg and other foods that cause allergy before nine months may help prevent allergies, says Palmer.
"The thinking is that introducing these foods early helps babies develop a tolerance and the allergy prevention advice from the Australasian Society for Clinical Immunology and Allergy is to introduce solids from four to six months of age."
But this recommendation from medical allergy specialists clashes with the new NH&MRC guidelines for feeding babies – still in draft form – that recommends giving babies breast milk alone for the first six months. As Palmer points out, this advice originates from the World Health Organisation and is aimed at preventing infection in babies – a problem that's less common in developed countries like Australia where allergy is more of an issue.
So what's a bewildered parent to do?
"The best advice is to keep breastfeeding for at least six months and use your intuition about introducing solids after four months if the baby seems ready to try them," she says.
As for eating in pregnancy, it's a similar story - don't shun common allergy foods like peanuts.
"Even when women have a food allergy themselves, they should only avoid the food they're allergic to. There's now more emphasis on mothers getting enough vitamin D, vitamin E and zinc. These nutrients are important for the immune system of both mothers and babies - it may be that getting enough of them can help prevent allergy," explains Palmer who's part of a research team looking at whether giving vitamin D to babies lowers their risk of allergies.
Although it's still not certain, vitamin D may be important for helping to prevent asthma too, she adds. In contrast to many European countries, Australian babies aren't routinely given vitamin D supplements - it's been assumed they get plenty of sunlight to make enough of the vitamin themselves.
"But even in Perth we find some pregnant women are low in vitamin D. In Australia our practices around sunlight exposure have changed – you now see babies with wraps over their prams to protect them from the sun, for instance. "
What about supplements of omega 3 fats, probiotics or prebiotics – can they help prevent allergies?
"Research in Perth found that giving omega-3 fats directly to young babies didn't make a difference, but Adelaide researchers found that the babies of women who took omega-3 supplements in pregnancy were less likely to have egg sensitisation (meaning they had a lower risk of egg allergy), and, to a lesser extent, less likely to have eczema," she says. "With probiotics and prebiotics, there's no strong evidence for mothers or babies – but they won't do any harm."
Has food allergy been a problem for your kids?