According to a study published in the Journal of Allergy and Clinical Immunology, early childhood vitamin D deficiency may increase the risk of asthma, respiratory tract infections, and allergies. To investigate this association, researchers tracked a group of children—all at high-risk of developing allergies—for their first ten years of life. They measured the children’s vitamin D levels and tested them for asthma, allergies, and respiratory tract infections at six months old and at one, two, three, four, five, and ten years old. Analyzing this data, the researchers found that:

• Children who were repeatedly found to be vitamin D-deficient had a higher risk of developing asthma, eczema, or other allergies by age ten.
• Vitamin D deficiency at six months old was associated with two markers of heightened asthma risk: a higher chance of carrying bacteria in the upper airways, and a younger age at the time of their first lower respiratory infection that included fever.

This study was the first to track this relationship from birth to age ten, and shows compelling evidence of a vitamin D deficiency–asthma risk association. More research is needed, however, to understand how different forms of vitamin D could affect asthma risk. As for where to get vitamin D, sun exposure stimulates the body to make it itself, but it may not be enough for those living in areas with low sunlight intensity for much of the year. In addition, staying inside, covering up while outside, and using sunscreen all diminish your body's ability to make vitamin D. Other ways to get vitamin D include eating fatty fish, such as salmon and tuna, and fortified foods such as milk, orange juice, and yoghurt. A vitamin D supplement is another option, although it’s always a good idea to speak with your child’s paediatrician before giving them any new supplements.

Source: Journal of Allergy and Clinical Immunology