New federal guidelines issued Thursday recommend exposing babies to peanuts early on to prevent the development of a dangerous allergy to the food. In a turnaround, the National Institutes of Health says landmark research has found that allowing babies to eat peanut-containing items before their first birthday dramatically lowers their chances of becoming allergic to the nut later on. The guidelines specify that various risk factors determine whether exposures at different ages may be more effective at preventing the allergy. Officials are also quick to point out that these guidelines require a checkup before anything is tried at home. “We’re on the cusp of hopefully being able to prevent a large number of cases of peanut allergy,” said Matthew Greenhawt, a member of the NIH panel that penned the new guidelines.