Can vitamin D deficiency cause hair loss?

Vitamin D deficiency is unavoidable in certain situations. Through our daily diet we can only take in a very low amount of vitamin D, since most foods contain none, or very little, vitamin D. These include meats, fatty fish and some cereals. Instead, our body synthesizes vitamin D with the help of sunlight. This means that in areas where the amount of sunshine is low, a vitamin D deficient state develops, at least during the autumn and winter months.

Routine blood tests generally do not include a vitamin D level measurement. Due to the lack of diagnosis, even pathological cases can develop. In fact, around the world, approximately 1 billion people are estimated to have very low concentrations of this vital vitamin in their bodies. 

The connection between vitamin D and hair loss

There are some nutrients that, if missing from our diet in the long term, can cause hair loss. These include B vitamins, proteins and omega-3 fatty acids. But vitamin D also plays an important role. 

Vitamin D helps maintain the health of teeth and bones, and is also responsible for hair growth. If our vitamin D level is low, it has a negative effect on hair growth. The exact mechanism behind this is not yet fully understood.

Alopecia Areata and Vitamin D Level - What Does Science Say?

A scientific research study published in 2014 in the British Journal of Dermatology examined the connection involving vitamin D levels in the blood of patients suffering from alopecia areata.

Alopecia areata is an autoimmune condition that causes inflammation of the hair follicles while the hair cycle is in its anagen, or growth, phase. This is what causes the hair to fall out at an abnormal rate.

This study found that patients suffering from alopecia areata had significantly lower vitamin D levels than the control group not affected by hair loss. It was also shown that those most affected by hair loss had the lowest vitamin D values. 

The authors of the study noted that patients with alopecia areata should be tested for vitamin D levels and should receive vitamin D supplementation if a deficiency occurs.

Another study in 2013 specifically examined the relationship between vitamin D levels and hair loss in women. The women included in the study either had age-related hair loss or were affected by telogen effluvium. Telogen effluvium is a common condition that involves thinning of the hair. It occurs when too many hair follicles enter the telogen, or resting, phase. When too many hair follicles are in the resting phase instead of growing, it results in hair loss.

This study found a connection between low vitamin D levels and excessive hair loss. It also established that measuring vitamin D levels and taking vitamin D supplements should be standard practice in the treatment of female hair loss. 

Why does vitamin D affect hair loss?

What is the connection between vitamin D and hair loss? The authors of one piece of research believe they have found a possible answer to the problem. In the study conducted in 2016, blood was not the only thing taken to test vitamin D levels. In patients with alopecia areata, as well as androgenetic alopecia, also known as male-pattern baldness, small biopsies were also taken from the scalp skin. 

Researchers looked for the presence of vitamin D receptors in keratinocytes, the dominant cells making up the epidermis, which are responsible for the growth and development of hair follicles. Vitamin D receptors are tiny markers found on the surface of these cells that signal to vitamin D molecules that the cell needs vitamin D. 

The study found that in those affected by hair loss, the concentration of vitamin D receptors was significantly lower. This proves that a deficiency in vitamin D can cause hair loss.

Symptoms of vitamin D deficiency

The following symptoms can occur with a low vitamin D level: 

•  Bone pain and aches that may predispose to fractures and breaks
•  Non-specific muscle pain and weakness
•  Slow wound healing
•  Weakening of the immune system
•  Feeling of fatigue, lack of energy and irritability
•  Depression
•  Itchy skin
•  Hair Loss