The vitamin D receptor (VDR) is a protein that binds with vitamin D on genes and regulates hundreds of functions in the human body. Research has found that the VDR significantly affects 229 genes, including genes that are associated with autoimmune conditions and cancer. Studies have also found that vitamin D receptors are located in the hair follicles and play a role in normal hair cycling.
Alopecia is a medical condition in which the immune system attacks the hair follicles, resulting in patterned hair loss. This condition has two types: alopecia areata (AA), which is characterized by inflammatory hair loss, and androgenetic alopecia (AGA), also known as male or female patterned baldness.
Vitamin D deficiency has been associated with both AA and AGA in past studies. It is hypothesized that vitamin D’s anti-inflammatory properties, and its role in epidermal cell proliferation may be responsible for its role in inflammatory and skin conditions such as AA and AGA. Additionally, AA has been linked to a mutation to the VDR gene. However, no studies to date have evaluated whether VDR levels are linked with alopecia; therefore, researchers recently sought to find out if the VDRs in the skin and blood could serve as a potential pathogenic marker for these conditions.
This study included 60 patients, 20 with AA, 20 with AGA and 20 sex-matched control patients. The researchers excluded patients based on the use of drugs which could cause hair loss such as retinoids, anticoagulants and andantithyroids. They also excluded those who were pregnant or lactating, those with a history of anemia and thyroid diseases, individuals who supplemented with vitamin D for the last 2 months or were treated with topical vitamin D analogs and patients receiving phototherapy.
Serum VDR (s.VDR) and tissue VDR (t.VDR) samples were collected from all 60 patients in the study. Here is what the researchers found:
- VDR levels and t.VDR levels were significantly lower in AA and AGA patients than in the control group (p < 0.001).
- No significant differences in s.VDR and t.VDR levels between the AA and AGA patients (p = 0.343 and 0.838, respectively).
- VDR was significantly associated with t.VDR in those with AA, AGA and controls (p < 0.001, p = 0.005, p < 0.001 respectively), indicating that serum VDR levels could be used as a less invasive form of measuring VDR.
- VDR was negatively associated with disease severity in patients with AA (p = 0.013).
The researchers concluded:
“The current study suggests an important role for VDR in the pathogenesis of AA and AGA through documenting lower serum and tissue VDR levels in AA and AGA patients in comparison with the controls.”
While the number of vitamin D receptors located in the body is determined by genetic factors, learning that you have a low VDR count could be an important diagnostic tool for prevention or management of certain conditions. It is also important to note that a low VDR count may contribute an increased risk for vitamin D deficiency. The Vitamin D Council recommends supplementing with 5,000 to 10,000 IU vitamin D3 daily to maintain a healthy vitamin D status.
While this study was small and limited by its observational design, it did suggest that VDR levels may have a pathogenic role in diagnosing AA or AGA. Further studies researching the relationship between vitamin D, VDR and alopecia are needed.
Peterson, R. & Cannell, JJ. Vitamin D receptor could play an important role in the pathogenesis of alopecia. The Vitamin D Council Blog & Newsletter, 2016.