Not getting enough vitamin D can weaken bones, teeth, and muscles by interfering with calcium absorption. Lack of the vitamin has also been implicated in dementia and an increased risk of colorectal cancer. Now there's another reason to avoid a serious D deficiency: it can make respiratory tract infections much worse, according to a new study.

Severe vitamin D deficiency is associated with a higher rate of hospitalization for respiratory tract infections such as bronchitis and pneumonia, according to a new study led by the University of Surrey.

Severe vitamin D deficiency is associated with a higher rate of hospitalization for respiratory tract infections such as bronchitis and pneumonia, according to a new study led by the University of Surrey.