A new powdered peanut product is the first food item allowed to claim it may reduce peanut allergies in infants, though parents of susceptible babies are urged to consult a doctor before trying it. The product, called Hello, Peanut, can be mixed into puréed baby food to expose infants to peanuts starting around five months old.

The Food and Drug Administration allowed the new item, developed by a physician, to make the claim just months after the nation’s top allergy experts reversed longstanding advice on preventing peanut allergies, dropping recommendations to withhold all peanut-containing foods in early childhood in favor of early, frequent exposure, starting with peanut powder or extract for infants beginning to eat solid food. The label warns that evidence is limited.

While many foods like whole grains, nuts and supplements carry qualified health claims stating that they may reduce the risk of diseases like cancer or heart disease, this is the first time a food product label will be allowed to make a qualified claim that it reduces the risk of an allergy, officials said. A qualified claim means there is evidence supporting the claim, but it is not conclusive.

“This is a very important claim for us to allow to be incorporated into food labels,” said Dr. Scott Gottlieb, the commissioner of the F.D.A. “The guidelines for how to approach allergens in children are changing, the science is changing, and it’s important for parents to know.”