For decades parents have been told to delay feeding their children certain foods they could be allergic to, including peanuts, eggs, wheat, and milk. But recent studies suggest exposing at-risk children to potential allergens as infants might actually prevent them from developing an allergy.
One such study is a follow-up to groundbreaking research published this year, which suggested feeding peanut-containing foods to babies protects them from developing an allergy through at least age 5, and that protection remained with the youngsters even when they stopped eating peanut-containing foods for a year.
According to the study authors, 4 years of exposure to peanut-containing foods is sufficient to prevent an allergy in high-risk children.
A second new study suggests this early prevention strategy might also work with eggs. These researchers found allergies to peanuts and eggs were less common in young children who started eating those foods at 3 months of age than in children who received only breast milk during infancy.
Statistics from the U.S. Centers for Disease Control and Prevention (CDC) show food allergies are increasing among children. In fact they increased 50% between 1997 and 2011. Scientists aren’t sure why this is the case, but there are numerous possible culprits.
Scientists believe the Western Diet has made people more susceptible to developing allergies and other illnesses. Researchers base this theory on studies showing a substantial difference in the gut bacteria of children from various parts of the world.
One such study compared the gut bacteria from 15 children in Florence Italy to gut bacteria in 14 children living in a rural African village in Burkina Faso. The Italian children ate a diet high in sugar, animal-fat, and calorie-dense foods, whereas the African children were mainly vegetarians, as their community produces its own food. 
Researchers found the gut microbes of the European children showed far less biodiversity than the gut microbes of the African children.
Another theory says children in developed countries simply aren’t exposed to enough bacteria. In the West, children are exposed to controlled infectious diseases, thanks to proper sanitation and clean water. This is a good thing, but not all bacteria are evil organisms to be feared. Children in poor countries regularly die from illnesses that can be easily cured in the West, but they don’t have obesity, food allergies, asthma, gastrointestinal diseases, or autoimmune diseases. 
It could be that parents merely wait too long to expose their children to certain foods. In an effort to prevent their child having a severe allergic reaction, they inadvertently set him or her up for allergies in the future.
The results from last year’s study led to new draft guidance issued recently by the National Institute of Allergy and Infectious Diseases. The institute now recommends giving at-risk children peanut-containing foods as young as 4-6 months of age. Infants at risk are those with severe skin rashes or egg allergies. Allergy tests are recommended beforehand.
The institute will issue final guidelines following a 45-day comment period.
Dr. Gary Wong, a Hong Kong pediatrician who wrote an editorial in the online edition of the New England Journal of Medicine that accompanied the new studies, said:
“Evidence is really building up. It appears early introduction would be better off than avoidance.”