The American Academy of Pediatrics published updated guidance on what works and what doesn't when it comes to the prevention of food allergies and other allergic conditions. The new guidelines continue to remove the introduction of what are thought to be highly allergenic foods such as peanuts, fish, and milk.

There is no precise evidence that delaying the introduction of allergenic foods such as fish, peanuts and even milk, beyond 4 to 6 months of age works in preventing food allergies on children. In addition,there is strong evidence that an early introduction of peanuts, as early as 4 months old, may prevent the development of a peanut allergy in infants.

"There is no reason to delay giving your baby foods that are thought of as allergens like peanut products, eggs or fish," Dr. Scott Sicherer, a co-author of the report, said in a statement. "These foods can be added to the diet early, just like foods that are not common allergens, like rice, fruits or vegetables."

The gastrointestinal tract is the center of a set of immune system cells, and when these cells gets a taste of the allergenic proteins in different foods, they take up the proteins and eventually become tolerant to them. Dr. David Stukus, a pediatric allergist and associate professor of pediatrics in the Division of Allergy and Immunology at Nationwide Children's Hospital, said that's true "as long as it's introduced early and in an ongoing fashion," meaning there is a span of time during the introduction of these foods to the cells may lead the body to become tolerant.

And early introduction to food, for children 4 months to 6 months of age, said Stukus, was not involved with the new guidelines.

The report also looked at whether breastfeeding protects children against wheezing, asthma, food allergies and eczema.  

Breastfeeding exlcusively for the first three to four months of an infant was found to be protective against eczema, the researchers concluded in their study. Any amount of breastfeeding beyond that time, even if the breastfeeding is not exclusive, was found to be protective against wheezing in the first two years of a child's life and asthma in the first five years and even later in their life. The report says no conclusion could be made regarding the link of breastfeeding to its effect on the prevention of food allergies.

No particular evidence was found that avoiding allergenic foods during a mother's pregnancy or during breastfeeding of an infant worked in the prevention of allergies and its reaction. Neither did the use of special hydrolyzed formulas, even in children who were at high risk of getting food allergies. 

"I really appreciated the comprehensiveness of this clinical report," said Dr. Wendy Sue Swanson, a general pediatrician and chief of digital innovation at Seattle Children's Hospital.

Swanson, who has long advocated for the early introduction of a diversity of foods in children, described feeling grateful for the study and the guidance, given the ongoing changes and results in the understanding of allergy prevention.