Allergies in the Breastfed Infant

By Mary Bibb, BA, IBCLC

Allergic (atopic) conditions have complicated causes involving both genetic and environmental factors. Scientists say that if a child has one atopic parent, there is a 29% chance that child will develop allergies. If both parents are atopic, there is a 47% chance the child will develop allergies. Some studies put these genetic risks even higher!

What can parents do to reduce the risk of allergies and help their children enjoy the best health? The evidence is clear that 6 months of exclusive breastfeeding makes a difference. In one long-running study, a group of children were observed for 17 years. They were divided into 3 groups: babies who were breastfed for less than 1 month or not at all, babies breastfed for 1-6 months, and babies who continued to receive some breastmilk past 6 months. The babies who were breastfed the longest had less eczema as well as fewer food and respiratory allergies.  While not a guarantee that a child will be allergy free, the protection provided by breastfeeding lasted throughout childhood and the teen years.

Researchers have looked at other steps parents can take. It is very important to keep cigarette smoke out of the house.  It makes sense for mothers to have a balanced diet, with a variety of foods eaten in moderation. 

In at-risk families, where the parents have food allergies, removing common allergenic foods such as eggs or dairy from the mother’s diet during pregnancy and lactation may reduce conditions such as eczema, wheezing, and other respiratory symptoms in the baby. And, if a baby is diagnosed with Cow’s Milk Protein Intolerance, the mother can eliminate all cows’ milk and dairy products from her diet and still continue to breastfeed her baby.  Cow's milk protein allergy has been linked with colic in some infants, along with other symptoms such as flecks of blood in the stools.  However, new research suggests that cow milk allergy is less common than previously believed.  Trial removal of dairy products for 2-3 weeks to see if symptoms improve should be followed by a cow milk challenge (where dairy is re-introduced into the mother's diet).  This should be medically supervised and will tell whether improvements are because of the elimination. Putting mothers on food eliminations diets is stressful and should be avoided unless clearly required.  Other things besides allergy can cause colic and blood in the stools, for  example, infections.

Experts no longer give out lists of foods to be avoided while breastfeeding, but it makes sense to avoid foods or medications known to cause problems in family members. If Daddy breaks out in hives when he eats strawberries, Mom should avoid strawberries in her diet when she is pregnant or nursing. There is good evidence that peanut protein can get to the baby before birth and through breastmilk. Because peanut allergies can provoke anaphylactic reactions (a kind of extreme allergic reaction that can cause difficulty breathing and may be life threatening) mothers who have family members with asthma or known peanut allergies should avoid eating peanut products during pregnancy and lactation.

Parents should talk with their doctor if the baby is wheezing, has rashes, frequent colds, or blood in the bowel movements. Tests can help indicate if the problem is related to an allergy. Human milk contains immune factors, anti-inflammatory factors, and the perfect nutrition to help your baby grow. This is important protection for the allergic infant, who may face more risk of illness.


Arvola T. et al. Rectal Bleeding in Infancy:  Clinical, Allergological, and Microbiological Examination, Pediatrics 2006; 117(4):e760-768.

Goldman,A: Anti-inflammatory Properties of Human Milk, Acta Paediatr Scand 1986;        75:689-695.

Karunasekera K, Jayasinghe J, Alwis L: Risk Factors of Childhood Asthma: A Sri Lankan Study, J Trop Pediatrics 2001; 47:142-145.

Saarinen U, Kajossari M: Breastfeeding as prophylaxis against atopic disease: prospective follow-up study until 17 years old, Lancet 1995; 346:1065-69.

Vadas P, Wan Y, Burkes W, et al: Detection of Peanut Allergens in Breast Milk of Lactating Women, JAMA 2001; 285:1745-1748.


See also topics on Colic and Colitis (links)

Reviewed by Barbara Wilson-Clay, BS, IBCLC