While nursing has been shown to help prevent allergies in babies, other common practices, such as avoiding certain foods during pregnancy, using soy formula, or waiting until a baby is six months old to introduce solid foods have not shown any benefits, according to a new report published in the journal Pediatrics.

In this latest advisory, the American Academy of Pediatrics updates earlier suggestions that might have made some parents feel as if they weren’t doing enough to prevent allergies and asthma. in 2000, the group advised mothers of infants with a family history of allergies to avoid cow’s milk, eggs, fish, peanuts and tree nuts while breast-feeding. This advice has been tossed out, along with the suggestion to delay a child’s introduction to certain foods.

The only surefire advice remaining is to breast-feed. Exclusive breast-feeding for at least three months protects against wheezing in babies, but it is unclear whether it prevents asthma in older children.