Figure 1. A paradigm for how adequate vitamin D status in pregnancy and in early life may prevent the development of asthma and allergies.

Vitamin D has been shown to affect in utero lung growth and development. Since the lung continues to develop post-natally, this vitamin D effect likely persists through this period. This paradigm also accounts for the effects of vitamin D on the developing immune system, on innate immune responses, and the anti-inflammatory effects. Reprinted with permission from Litonjua²⁶.