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Baby Supplements, Asthma, Allergy Linked

May 5, 2003 -- Giving vitamin supplements to infants just might increase their risk of developing asthma or food allergies, according to a study reported at a major pediatric conference. The findings could help explain an epidemic of allergies and asthma among children in the United States, but more research is needed to confirm the association.

The study, presented at the 2003 Pediatric Academic Societies meeting in Seattle, followed more than 8,000 infants from birth to age three. The link between vitamin supplements and allergies and asthma was strongest for formula-fed African-American children, who were almost twice as likely to develop food allergies and one-and-a-half times as likely to develop asthma if they were given vitamins during their first six months.

The study comes just a month after the American Academy of Pediatrics (AAP) recommended vitamin D supplements for infants. The group noted that vitamin D deficiency is a particular problem for breastfed infants, because breast milk contains little of the vitamin. Vitamin D is needed for the absorption of calcium to develop strong bones.

"We certainly are not saying that the AAP recommendation should not be followed," says Josh Milner, MD, researcher of the new study. "This research is very preliminary, and we absolutely need more studies to find out if this association holds up. A lot more questions have to be answered before we can even begin to consider clinical recommendations."

Within the last few decades, asthma rates in children have more than doubled in the United States. It is estimated that almost 5 million children under the age of 18 suffer from asthma and 8% of children under the age of six have food allergies.

Milner and colleagues at Washington's Children's National Medical Center studied children born in 1988 for their first three years. Risk factors known to be associated with the development of asthma and food allergies were recorded, as was race and whether the infants were breast- or bottle-fed.

Among the 8,285 children, 11% developed asthma and 5% developed food allergies by the age of 3. Factors identified as increasing the risk for asthma included being male, having a smoker in the house, attending daycare, premature birth, being African-American, bottle-feeding, and low income. The risk of food allergies was higher in children who attended daycare and were breastfed.

When all these factors were controlled for, supplements use in the first six months was linked to a higher risk of asthma in African-American babies who did not breastfeed. Early supplements use was associated with a higher risk for food allergies in all races. Taking vitamins after infancy did not affect asthma risk and it is unclear whether it influenced food allergy risk.

Pediatric asthma and allergy specialist Marc Rothenberg, MD, PhD, calls the early study intriguing, and says the possible link between vitamin supplements and these disorders of the immune system deserves further study. But he says it is not yet clear if the association suggested in the study is real or can be explained by other factors not considered by the researchers.

He also questioned the value of an asthma study that followed children for only the first three years of life, because he says asthma is difficult to diagnose in very young children. Rothenberg is director of allergy research at Cincinnati Children's Hospital Medical Center.

"Given the epidemic of asthma and allergies, this is an important question to ask," he tells WebMD. But I don't think this study provides many answers."