Study Connects Exclusive Breastfeeding to Elevated Allergy Rates in Young Children

Infants fed only breast milk faced an 82 percent higher allergy risk in year one, 62 percent at age two, and 54 percent at age three.

Newborns who nurse exclusively typically feed 10 to 12 times daily, often every two hours from the start of one session to the next.

By DANYA SAPERSTEIN

JULY 27, 2026 07:08

Although the advantages of exclusive breastfeeding are widely recognized, fresh research reveals a connection to higher rates of childhood food allergies, prompting fresh debate on breast milk versus formula choices.

Breastfeeding offers clear upsides. The World Health Organization describes it as the ideal infant food and advises exclusive breastfeeding for the first six months. It has also been linked to better cognitive scores and fewer early asthma cases.

A team at the University of Toyama in Japan, headed by Professor Emeritus Hidekuni Inadera, examined data from the Japan Environment and Children Study to test for ties between breastfeeding and food allergies.

The researchers reviewed records from more than 88,000 mother-child pairs, dividing infants into four categories: fully formula fed for six months, breastfed for under six months, partially breastfed with formula for six months, and exclusively breastfed for six months.

Children received yearly checks through age six for parent-reported and doctor-confirmed allergies.

Exclusive Breastfeeding Shows Both Gains and Drawbacks

The analysis confirmed certain benefits. Exclusively breastfed children had a 37 percent lower asthma risk in the first year and a 19 percent lower risk in the second year.

They also showed lower chances of allergic rhinoconjunctivitis, similar to hay fever.

Yet food allergy risks rose sharply. Exclusively breastfed children had an 82 percent higher risk in year one, 62 percent at age two, and 54 percent at age three, with the added risk easing after that point.

The pattern differed by sex, showing stronger effects among boys.

Researchers noted other possible reasons for the link beyond breastfeeding itself.

Timing of Solid Food Introduction Influences Allergy Development

One factor may be the age when other foods enter the diet. Earlier studies indicate that introducing common allergens such as eggs and peanuts between four and six months can help prevent allergies.

This pattern gained attention in Israel, where peanut allergy rates are lower than among children of similar background in the United Kingdom.

A New England Journal of Medicine study highlighted that early peanut exposure, often via the snack Bamba in Israel, reduced risk when started between four and 11 months of age.