Breastfeeding protects babies against allergic hay fever

By Child Health Monitor

Background:
Many articles in CHM have dealt with the benefits of breastfeeding, and the leading article in this issue looks at links between breastfeeding and higher IQ, especially in babies born malnourished due to problems with the placenta. Breastfeeding also stimulates a baby's immune system, promotes growth and development, prevents obesity, and one other potential benefit of breastfeeding may be the prevention of allergies such as hay fever, eczema and asthma. There have been quite a few recent studies done on whether breastfeeding really does prevent allergies, but the results have been rather confusing. To deal with this, these authors undertook a systematic review of gold-standard studies that looked at whether breastfeeding prevented allergies, specifically allergic rhinitis (hay fever).

Findings:
To examine the link between breastfeeding and allergic rhinitis, these researchers first identified all the studies that had examined this issue. The types of studies they found included (1) cross-sectional studies: studies that looked at mothers and babies at a single moment in time to see how many in each breastfeeding category got hay fever, and (2) prospective studies that followed mother and baby from birth for a period to time to see how many babies in each category developed hay fever. The researchers decided only to include well-conducted prospective studies in their systematic review as these produce the best evidence. They only included studies that examined links between breastfeeding between birth and three months of age, and later hay fever in the child. Only six studies met their criteria to be included in their systematic review.

Analysing the results of all the six studies together showed that breastfeeding for the first three months of life was definitely protective against the child developing allergies such as hay fever. The protective effect was 0.74, meaning that the children who were breastfed were one-quarter less likely to develop allergic hay fever in their first years of life. If these children came from a family with a strong history of allergies, breastfeeding was less protective - these children only had a 10% reduction in risk of hay fever from breastfeeding. The authors concluded that this was definite evidence that breastfeeding for the first three months protected against at least one type of allergy, allergic rhinitis, in all children whether they had a strong family history of the problem or not. Yet more evidence that "breast is best".

Reference:
Bloch et al. Does breastfeeding protect against allergic rhinitis during childhood? A meta-analysis of prospective studies. Acta Paediatrica April 2002; 91: 275 ? 279.

Action Points:

• Breastfeeding your baby protects them against allergies such as hay fever.
• Breastfeeding for the first three months makes a child one-quarter less likely to get allergic hay fever.