Taking vitamin D supplements in pregnancy can positively change the immune response of the newborn baby, which could help to protect against respiratory infections and asthma, says a study.

"The majority of all asthma cases are diagnosed in early childhood implying that the origin of the disease stems in foetal and early life," said lead researcher Catherine Hawrylowicz from King's College London.The team of researchers looked at the effect that taking a supplement of 4,400 IU (International Unit) vitamin D3 per day during the second and third trimesters of pregnancy versus the recommended daily intake (RDI) of 400 IU/day, had on the immune system of the newborn.

The study published in the Journal of Allergy and Clinical Immunology showed that higher vitamin D levels in pregnancy may improve the immune response of the newborn baby.Given the evidence for strong immune responses in early life being associated with decreased development of asthma, the team believes the effect will likely lead to improved respiratory health in childhood.

"Studies to date that have investigated links between vitamin D and immunity in the baby have been observational. For the first time, we have shown that higher Vitamin D levels in pregnancy can effectively alter the immune response of the newborn baby, which could help to protect the child from developing asthma," Hawrylowicz said.