PHILADELPHIA — Giving infants vitamin D in the first year of life held no major advantage in preventing allergies, although there were trends in that direction, the large VITALITY trial showed.
Among more than 2,700 healthy breastfed babies, daily vitamin D supplementation didn’t reduce the odds of developing any food allergy by 12 months (OR 0.915, 95% CI 0.714-1.174, P=0.485).
However, vitamin D given at least 4 days a week showed a consistent trend for lower incidence of the four main allergens — peanut, egg, cow’s milk, and cashew, Kirsten Perrett, MD, PhD, of Murdoch Children’s Research Institute in Parkville, Australia, reported at the American Academy of Allergy, Asthma & Immunology annual meeting.
“This suggests, if vitamin D was adhered to at the population level, it may provide a safe and affordable strategy to confer modest protection against food allergy,” the group concluded.
Because breast milk doesn’t provide enough vitamin D for infants, supplementation is recommended in U.S. federal dietary guidelines for all babies: 400 IU per day before 12 months of age, and 600 IU from 12 to 24 months.
Australia neither recommends universal vitamin D supplementation for infants nor routinely fortifies the food chain supply, making it “uniquely placed internationally to assess the role of vitamin D in early life development,” as the researchers noted in their protocol.
Deficiency is less common in the U.S., where milk is fortified with vitamin D, noted Alkis Togias, MD, chief of the Allergy, Asthma, and Airway Biology Branch at the National Institute of Allergy and Infectious Diseases in Rockville, Maryland.
In the study, nearly 88% of the placebo-group infants were deficient (serum concentration of 25-hydroxyvitamin D ≤49 nmol/L). A recent U.S. study found 12% of 8- to 24-month-olds had levels that low, although some reports have raised concern about a resurgence of vitamin D deficiency and rickets.
Vitamin D has many roles in the body beyond just preventing rickets, and low levels have been tied to increased risk of severe asthma, although trials have not borne out a protective effect.
“There was a lot of excitement in the past about vitamin D given very early to children to prevent asthma. So there have been studies actually in the U.S. for asthma, but not for food allergy,” Togias noted.
Given the vitamin’s immunomodulatory function, Perrett’s group conducted a phase IV single-center trial in 2,739 healthy, term, breastfed infants (51% male) ages 6 to 12 weeks who were recruited at their first immunization due to not already receiving vitamin D supplementation. Among them, 89.2% had a family history of allergy, and 3.3% had a physician diagnosis of eczema at baseline.
These infants received by random assignment either vitamin D (400 IU cholecalciferol daily) or placebo until age 12 months. Adherence was fairly good, with 63.2% of participants getting their assigned drops at least 4 days a week to 12 months of age and a similar rate between groups.
The primary outcome was food allergy to at least one of 10 allergens assessed via an algorithm incorporating oral food challenge, skin prick testing, and parent-reported ingestion and reaction history.
In a “complete case” analysis of 2,101 infants breastfed for at least 6 months who were fully compliant with the randomization and achieved expected vitamin D levels, prevalence of any food allergy still didn’t show an advantage to vitamin D (13.6% vs 15.2% with placebo, OR 0.874, P=0.280).
For individual allergens in the complete case analysis, odds ratios were more supportive of a benefit for vitamin D supplementation in the following:
Peanut: 0.616 (P=0.093)Egg: 0.720 (P=0.042)Cow’s milk: 0.505 (P=0.039)Cashew: 0.352 (P=0.011)
“The study is restricted to breastfed infants because formula feeding from birth can be equivalent to vitamin D supplementation as formula contains approximately 400 IU of vitamin D/L,” the researchers noted in their protocol. “The amount of formula that infants consume by age 6 months is based on body weight and amount of solid food consumed but generally can be considered to be equivalent to the infant receiving <400 IU.”
Further analyses from the trial should provide information on eczema and bone health in later childhood — “the historical basis of widespread postnatal vitamin D supplementation, which remains essentially untested,” the VITALITY researchers noted.
