The role breastfeeding plays in preventing allergies and asthma in children is unclear.

Studies undertaken since the 1980s have provided conflicting information about whether breastfeeding is more likely or less likely to protect infants from developing these conditions.

For instance, a Swedish study found that exclusive breastfeeding during the first four months of life reduces an infant’s likelihood of having asthma. Meanwhile, a New Zealand study found that breastfeeding may double the eventual risk of asthma and allergies for a child. It is possible that breastfeeding may protect a child against allergies and asthma during the early years, but may increase the likelihood of developing these conditions later.

What is beyond dispute is that breastfeeding offers many benefits for children (and mothers) apart from allergy/asthma protection. For this reason, most experts continue to strongly urge new mothers to breastfeed their babies exclusively for at least the first six months of life. Some recommend at least partial breastfeeding for up to one year.