Can vitamin D deficiency cause hair loss?

The development of vitamin D deficiency is unavoidable in certain situations. With our daily diet we can take in only a very small amount of vitamin D, since most foods contain none or very little. Such foods include meats, fatty fish and some grains. 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 in the autumn and winter months.

Routine blood tests usually do not include a vitamin D level measurement. Because of the lack of diagnosis, even pathological cases can develop. In fact, it is estimated that around 1 billion people worldwide have a very low concentration of this vital vitamin in their body.

The link between vitamin D and hair loss

There are some nutrients which, 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 it is also responsible for hair growth. If our vitamin D level is low, it has a negative effect on hair growth. The exact mechanism of this is not yet fully understood.

Alopecia areata and vitamin D levels – what does science say?

A scientific study published in the British Journal of Dermatology in 2014 examined the relationship between the vitamin D levels in the blood of patients with alopecia areata.

Alopecia areata is an autoimmune condition that results in inflammation of the hair follicles when the hair cycle is in its anagen, or growth, stage. This causes the hair to fall out at an unnatural rate.

This study found that patients with alopecia areata had far 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 deficient state occurs.

Another study in 2013 examined the relationship between vitamin D levels and hair loss specifically 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. If too many hair follicles are in the resting phase rather than growing, hair loss results.

This study found a connection between low vitamin D levels and excessive hair loss. It also concluded that measuring vitamin D levels and taking vitamin D supplements should be standard 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 study believe they have found a possible answer to the question. In the research carried out in 2016, they did not only take blood to test vitamin D levels. In patients with alopecia areata, as well as in those with androgenetic alopecia, also known as male pattern baldness, a small biopsy was taken from the skin of the scalp.

They looked for the presence of vitamin D receptors in keratinocytes, the dominant cells forming the epidermis, which are responsible for the growth and development of hair follicles. Vitamin D receptors are tiny markers 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 shows that vitamin D deficiency can cause hair loss.

Symptoms of vitamin D deficiency

The following symptoms may be experienced with low vitamin D levels:

• Bone pain and aches, with a tendency to bone 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