breastfeeding newbornSeventeen seems to be the magic number to best protect a baby against the development of food allergies. A recent British study found that babies who are fed only breast milk until at least 17 weeks old are less likely to develop food allergies by age 2.

The study involved 1,140 babies born between January 2006 and October 2007. Each mother kept a baby-feeding diary for the first year. The diary included how long (or if) a baby was nursed, when or if cow’s milk was introduced to its diet, and when solid foods were introduced.

By age 2, 41 of these babies had developed medically diagnosed food allergies. An additional 82 babies were selected to serve as a control group, matching the allergic babies in factors that included age, birth weight, length of gestation, and mothers’ allergies.

The study, published in the medical journal, Pediatrics, indicates: 

  • Infants who developed food allergies were less likely to be feeding on breast milk when cow’s milk proteins were introduced into their diets.
  • Those feeding on solids at 16 weeks or younger were more likely to develop food allergies.

When breastfeeding continued while cow’s milk was introduced, food allergies were less likely to develop.

Breast milk seems to strengthen the child’s immune system in ways other baby foods cannot. The early introduction of solid foods seems to have an immunologically diminishing effect.

Kate EC Grimshaw urges parents to “Don’t introduce solids until 17 weeks.” Grimshaw, a nutritionist at England’s University of Southampton, is the study’s lead author.

Grimshaw says waiting even longer to introduce solid foods is perfectly fine but it’s important that, at whatever age solids are introduced, breastfeeding continues. When breastfeeding is not an option, the recommendation to wait at least 17 weeks before introducing solid foods still stands.

The American Academy of Pediatrics recommends similar guidelines for allergy prevention. It recommends breastfeeding for one year or longer, and an introduction of solid foods between 4 and 6 months of age but not sooner, and complementary feeding of breast milk and solids until the child is 1 year old or older. The European Society of Pediatric Gastroenterology, Hepatology and Nutrition offers the same recommendations.

Children who experience food allergies are more prone to develop other autoimmune disorders such as asthma, respiratory allergies, and a form of eczema known as atopic dermatitis.


  1. Grimshaw, Kate EC, Ph.D., RD, et al. “Introduction of Complementary Foods and the Relationship to Food Allergy (abstract).” Pediatrics. The American Academy of Pediatrics. Nov 18, 2013. Web. Dec 11, 2013.
  2. Food Allergies in Children.” Allergist. American College of Allergy, Asthma and Immunology. n.d. Web. Dec 11, 2013.