It might seem unorthodox, but feeding peanuts to infants at risk of an allergic reaction could actually safeguard them.

Mounting evidence suggests that gradually introducing bits of peanut protein, such as peanut butter diluted with hot water, to high-risk babies as young as 4 months old might help them develop immunity. (Whole peanuts, however, are a choking hazard and should not be fed to babies and toddlers.)

The latest research, published in the New England Journal of Medicine, found most children who consume peanuts at an early age will remain allergy-free, even if they stop eating peanuts by age 6.

Now, the National Institutes of Health is proposing new guidelines recommending some children be fed peanut-containing foods — about 6 to 7 grams over three or more feedings — as early as age 4 to 6 months. The recommendation applies to children who are at high-risk because they already have severe eczema, egg allergy or both.

“In my gut it’s counterintuitive,” said Louise Larsen, of Westminster, Calif.

Larsen strained to ensure her daughter, now 19, never ate or touched the legumes again after a peanut butter and jelly sandwich sent her into anaphylactic shock, a life-threatening allergic reaction, at 15 months old.

But, Larsen added, “I do believe in science.”

Food allergies appear to be increasingly common — they now affect about 1.4 percent of U.S. children, according to a 2010 study by food allergists with Mount Sinai School of Medicine in New York. That figure is up from less than 0.5 percent in 1999.

There are a handful of theories for the rise — such as the one that says children are not being exposed to as many germs so their immune systems have changed — but no definitive explanation.

For some, eating cross-contaminated food or even consuming traces of peanuts, which can lurk undetected on countertops and on people’s hands, can be life threatening. The consequences aren’t always so severe — sometimes exposure results in hives.

Parents were once advised to delay introduction of peanuts into their children’s diets to avoid a dangerous reaction. But, for some, that thinking has shifted.

“If you delay too long, you have a higher risk of developing a peanut allergy,” said Dr. David Fleischer, an allergy specialist at Children’s Hospital Colorado who helped write the NIH guidelines.

However, the recommendations, which aren’t yet final, say those at highest risk should first get a skin prick test exposing them to a small amount of the allergen. Depending on how allergic the child is, the feeding might be best supervised or avoided.

The proposed guidelines draw upon the results of a clinical trial in the United Kingdom, published last spring. Known as the LEAP trial, it involved 640 infants with severe eczema, egg allergy, or both. They were divided into two groups, one with families avoiding peanuts and another with children fed peanut butter weekly for five years. Nearly 14 percent of those who avoided peanuts became allergic, compared to 2 percent of those who didn’t.

Research published in the journal this month built upon the LEAP study. This time, every participant avoided eating peanuts for one year. After that 12-month hiatus, 4.8 percent of participants who had been exposed to peanuts as infants developed allergies compared to 18.6 percent from the original avoidance group of infants, researchers said.

Pediatricians who specialize in allergies say the findings are promising.

“This study is something we’ve been waiting a long time for,” said Dr. Wan-Yin Chan of CHOC Children’s Hospital.

The evidence validates how Chan approached peanuts with her own two girls, now 3 and 6, who had eczema as babies. She fed them peanut butter before they each turned 1. It was controversial at the time, Chan said, so she never recommended it to her patients. But she will soon, now that increasing evidence and new guidelines suggest it’s not only safe but beneficial, she said.