There is no evidence that delaying the introduction of allergy-causing foods into a child's diet can prevent allergies at a later stage, a major food science conference in Dublin heard today.
Traditionally, the advice to weaning mothers has been to defer the introduction of allergenic foods like fish, soya and nuts to avoid "over-sensitising" the child, especially if parents fear the infant is at risk of developing allergies.
However, Dr Clare Mills, of the UK’s Institute of Food Research, said there was simply “no hard data” to suggest the early or late introduction of certain foods can prevent allergies.
The UK Food Standards Agency was recently forced to withdraw its advice to parents on the introduction of such foods for want of evidence either way, and this pattern was being followed in other countries, she said.
Dr Mills is co-ordinating one of the biggest international studies ever undertaken into food allergies, involving 55 data-collecting centres across 25 countries in Europe, Asia and Africa.
In an address to the annual conference of the European Federation of Food Science and Technology (EFFoST) in the Burlington Hotel, she said the incidence of food allergies in children and adults had increased dramatically in recent decades.
But the pattern and prevalence of allergies, even across industrialised countries, varied significantly, she said.
“What we found won’t make it easy to pinpoint which foods carry the biggest risk, as the risk for individual foods varies from country to country,” said Dr Mills. "For example, shrimp is an important allergen in Iceland but we found no cases in Bulgaria.
“On the wider picture, we found that food allergy overall is lower in southeast Europe than the northwest and lower still in India. Rates in Hong Kong were much higher.”
Dr Mills said there was still a dearth of knowledge regarding what specifically caused allergies but several hypotheses were being investigated, including the impact of nutrition during pregnancy, weaning practices and genetic predisposition.
In Ireland and Britain, the biggest problem foods were peanuts and, in infants, cow’s milk and eggs while in Mediterranean countries like Greece fish and shrimp were more problematic.
Scientists needed to study the relationship between patterns of consumption and incidences of allergies before the causes could be pinned down.
Improvements in food labelling had helped allergic consumers to avoid manufactured products that contain their problem food but there was still a problem with assessing the risk from foods made on common processing lines, Dr Mills said.
