People often ask me why are allergies on the increase, and is it just being over diagnosed? Well the answer is no, the increased prevalence is not secondary to over- diagnosis, in fact 1 in 10 Australian babies born today will develop a food allergy. We do not know why exactly but evidence suggests it is a combination of genetic predisposition as well as environment that determines allergies.
Leading researchers at the Murdoch Institute in Melbourne hypothesize the 5 D's as likely culprits for increased allergies;
1. Diet: Studies have found that parents who delay giving their babies allergenic foods could be doing more harm than good, with a 2011 study showing the rate of egg allergy significantly increases among toddlers who are introduced to the food after 12 months of age. The research finding contributed to the changes in the National Infant Feeding Guidelines which now recommend that parents should introduce solids such as eggs around the age of six months, not after 10 months as initially directed. This is supported by new research suggesting the same for peanut.
2. Vitamin D: infants who are vitamin D deficient were three times more likely to have an egg allergy and 11 times more likely to have a peanut allergy.
3. Dogs: having a dog that lives in the home could reduce the likelihood of allergies in infants. Additionally studies have revealed having older siblings reduces a child’s likelihood of developing an allergy. This finding supports the ‘hygiene hypothesis’ which is a theory which states that the immune system needs to be exposed to appropriate stimulation during development so that it is ‘trained’ to attack things that might cause us harm (such as bacterial or viral infections) while ignoring harmless things such as foods.
4. Dirt: Another finding that supports the hygiene hypothesis is a study which found that when babies used pacifiers that had been dropped on the ground, their risk of allergy was lower.
5. Dry skin: Researchers say the findings support the hypothesis that sensitisation to food can occur through the skin and dry skin may increase the risk for infants to become sensitised to common allergenic foods.
source: MCRI May 2015