TUESDAY, July 6, 2004 (HealthDayNews) -- Early use of multivitamins, a staple in the diets of more than half of all American toddlers, may boost the risk of asthma and allergies, a new study claims.
But it's too soon for parents to change anything unless their doctor advises it, stressed study author Dr. Joshua D. Milner, a clinical fellow at the National Institute of Allergy and Infectious Diseases at the National Institutes of Health. A report on the finding appears in the July issue of Pediatrics.
Milner and his colleagues evaluated more than 8,000 children, using data collected from the National Center for Health Statistics' 1988 National Maternal-Infant Health Survey and the 1991 Longitudinal Follow-Up of the same children.
The mothers of the children described whether they had given their children vitamins at an early age, and whether their kids were diagnosed with a food allergy or asthma.
By the age of 3, 851 kids, 10 percent of those studied, were diagnosed with asthmas. By age 3, 396 kids, or 4.9 percent of those studied, were diagnosed with food allergies.
In those kids who were formula-fed and took vitamins before 6 months of age, there was "about a 70 percent increased risk" for a food allergy, compared to kids who were formula-fed but not given multivitamins, Milner said.
For black infants, whether formula-fed or not, there was about a 30 percent increased risk for asthma at age 3 if they took multivitamin before 6 months of age, Milner added.
"Caucasian children had no increased risk for asthma, and breast-fed infants -- breast-fed at all -- did not have an increased risk for food allergies," Milner said.
The researchers could not explain why the asthma risk was stronger for black infants, but they speculated that doctors for some reason may be more likely to diagnose asthma in black infants.
Formula-fed infants may be more at risk for food allergies when they also take a multivitamin because of the higher amount of vitamin D found in formula, they also speculated.
"We have shown an association that may or may not be causal," Milner said. "There could be another reason for the finding."
"Certain vitamins have direct effects on the immune system and can push it in certain directions," he added. "Vitamins A and D can push the immune system in allergic directions; vitamins E and C have been shown in test tubes to push you away from the allergic direction. This doesn't mean if you take vitamin D you will get an allergy."
More than 50 percent of toddlers are given multivitamins, Milner estimated, and about 30 percent to 50 percent of infants take them. For children in general, he said, there is no official recommendation from the American Academy of Pediatrics.
However, the academy did recommend last year that healthy infants during the first two months of life along with children and adolescents should receive 200 international units (IUs) a vitamin D a day to prevent rickets, a skeletal deformity associated with insufficient levels of vitamin D.
Milner said, "The message for parents is they should not do anything differently than what their doctor says right now."
Another expert had mixed feelings about the new study.
"It is a fascinating study, although it has, I am afraid, the potential for a lot more concern than it warrants," said Dr. Dennis Ownby, section chief of Allergy and Immunology in the Department of Pediatrics at the Medical College of Georgia in Augusta. "As with any study like this, it's important to consider the risks and benefits in totality."
"For those who need supplements, the risk of rickets is real and is, in my opinion, a far worse problem than asthma," said Ownby, who noted that many children diagnosed early in life with asthma often outgrow it by age 6 or so.
"This article does highlight the concern of many health professionals, and especially pediatricians, that often parents get the idea that if a little vitamin is good, more is better. Vitamins, especially vitamin D, do have toxic effects..."
He echoed Milner's advice, that parents consult their pediatrician for guidance on vitamin use.
More information
For information on vitamin D supplementation, visit the American Academy of Pediatrics.
