Reports of peanut allergies have increased more than three-fold among U.S. children in the last 20 years, Anvari and colleagues note in JAMA Pediatrics. During this time, feeding guidelines have moved away from telling parents to avoid introducing some foods that can cause allergies until kids are 2 or 3 years old, and stopped telling women to avoid peanuts when they're pregnant or nursing. But many recommendations still stop short of urging parents to give babies eggs and peanuts early in life. For the current analysis, researchers summarized research published since 2008, when the American Academy of Pediatrics (AAP) revised its guidelines for peanut introduction to note there's no evidence to suggest waiting longer than six months could reduce the risk for allergies to this food.

After these guidelines and other similar recommendations came out, a shift in thinking about peanuts came courtesy of a study of 640 babies in the U.K. who were already at high risk for nut allergies because they had eczema or an egg allergy already, researchers note. This U.K. experiment compared the effects of giving some babies a 6-gram dose of peanut each week to strict peanut avoidance in children over a five-year period. All of the kids in the study got skin tests to determine if they developed a peanut allergy. At age 5, about 14 percent of the kids who avoided nuts had a peanut allergy compared with roughly 2 percent of the children who got an early taste of this food. Based on these results, some proposed guidelines may be shifting toward early introduction of peanuts even in babies with a history of other allergies, the authors note.

But when these high risk babies get that first taste of peanuts, they should have it in a clinical setting with lab tests to check for allergic reactions before parents offer peanuts to children at home, the researchers point out. This study had some limitations, including a lack of data on how much peanuts babies could have at one time or how long they might need to continue eating nuts on a regular basis to protect against allergies. It's also unclear what risks babies might face if they got a taste of peanuts then stopped eating them.

Still, guidelines in development from the National Institute of Allergy and Infectious Diseases are expected to come out soon and recommend that all kids get their first taste of peanuts around 4 to 6 months of age as long as they have tried some other foods first, said Dr. Matthew Greenhawt, a food researcher at the University of Colorado School of Medicine who wasn't involved in the current analysis. "Guidance regarding when to introduce peanut into the diet of an infant is changing, based on new research that shows that early introduction around 4 to 6 months of life, after a few other foods have been introduced into the infant's diet, is associated with a significantly reduced risk of such infants developing peanut allergy," Greenhawt added by email. "This is an amazing opportunity to help potentially reduce the number of cases of peanut allergy."

Babies, however, should stick to nut butters and pastes, said Dr. Robert Boyle, a pediatric allergy researcher at Imperial College London who wasn't involved in the current analysis." Whole nuts are not advised for babies or children up to the age of 3, due to the risk of choking," Boyle added by email.

Source: JAMA Pediatrics, November, 2016

Dr. Kenneth Backman of Allergy & Asthma Care of Fairfield County comments:"The past year has brought a great deal of new information about food allergy. It is now clear that infants at high risk of food allergy, such as those with severe eczema or known egg allergy, benefit from early introduction of peanut. As more studies are performed, we will learn more about when to introduce which foods. For now, it is clear that high risk infants should be tested for peanut, and if testing is negative, peanut should be introduced before age 1."