Hair Loss
Severe hair loss may be due to a variety of health reasons including vitamin D deficiency. Although research is limited, studies have established a link between the two in women. [11]
Alopecia areata (patchy baldness) has been linked to low levels of vitamin D. [12] Alopecia areata is an autoimmune disease that causes extreme hair loss on the head and other body parts. While alopecia areata is not directly caused by the deficiency, a study in people with the condition has shown that hair loss is more rapid and severe in those with vitamin D deficiency. [13]
Depression
Vitamin D deficiency can cause mood changes, such as depression. Depression is a mood disorder characterized by persistent feelings of sadness and loss of interest in normally joyful activities.
The relationship between depression and low vitamin D levels is yet to be fully defined. Some studies have found a link between depression and vitamin D deficiency, especially in older adults. [14] Up to 65 percent of observational studies on the subject have found a link between the two. In contrast, this link was absent in most controlled studies. [15] Still, some controlled studies have shown that vitamin D can help improve depression in deficient people. [16]
According to some researchers, the discrepancy in research findings is likely because the vitamin D dosages used in the controlled studies were low, or because many of the controlled studies did not last long enough to appreciate the effects of taking supplements. [17]