Infants who take multivitamins may be at a greater risk of developing asthma and food allergies, according to a new study out of the US, which appears to conflict with evidence linking low levels of antioxidant vitamins to higher risk of asthma.
Incidence of asthma has been climbing steadily in the Western world and is the most common long term condition in the UK today, according to the National Asthma Campaign. It is thought that a modern lifestyle, including pollution and hygiene, contributes to the risk of developing asthma, and diet could also play a role in this, believe some scientists.
Researchers from the Children's National Medical Center in Washington studied data from more than 8,000 children and found an association between early infant multivitamin intake and asthma among black infants.
They also found an association between early infant multivitamin intake and food allergies in formula-fed infants and an increased risk of food allergies among all children given multivitamins at age three.
The scientists believe vitamins may cause cell changes that increase the odds of an allergic reaction, but say as yet there is no proof this is the case.
Writing in this month's issue of Pediatrics (vol 114, no 1, pp 27-32), the researchers say: "Early vitamin supplementation is associated with increased risk for asthma in black children and food allergies in exclusively formula-fed children. Additional study is warranted to examine which components most strongly contribute to this risk."
A study published earlier this year found that higher levels of the antioxidants beta-carotene and vitamin C, and the trace mineral selenium, were associated with a lower risk of asthma in young Americans.