Vitamin D is understood to be one of the most important nutrients required for the body to function optimally and for an individual to be healthy.
A deficiency in this essential vitamin can have many negative consequences, and it has even been linked to hair loss directly and indirectly.
The negative impact of a vitamin D deficiency on the body can lead to conditions that cause hair loss as a secondary symptom, and there is evidence to suggest that vitamin D is directly involved in supporting the process of hair growth and hair follicle health.
In this post, you’ll learn the exact role that vitamin D plays in the body and, more specifically, in hair growth. You’ll also learn how you can tell if you suffer from this deficiency, which populations are most at risk, and how you can increase vitamin levels.
An Introduction to Vitamin D
Vitamin D is a group of fat-soluble vitamins that plays a role in many biological processes.
Perhaps its greatest role is that which increases intestinal absorption of other nutrients, such as calcium, magnesium, and phosphate (1). But this vitamin also has other roles, including modulation of cell growth, regulation of neuromuscular and immune function, and reduction of inflammation (2).
Interestingly, vitamin D is the only nutrient that your body (more specifically, your skin) can synthesize as a result of sunlight exposure (3).
The Impact of Vitamin D Deficiency on the Body
The daily recommended dietary allowance for Vitamin D varies by gender, age, and condition (4).
When levels of vitamin D drop these values, the body may begin to experience a deficiency and symptoms may begin to develop.
Depending on the extent of the deficiency, there can be a variety of mild to severe symptoms. These include (5):
- Fatigue and tiredness
- General aches and pains
- Overall weakness
- High blood pressure
- Depressed feelings
- Excessive perspiration
Prolonged deficiency can even lead to osteopenia and osteroporosis (6).
But that’s not all.
There are an array of other illnesses and conditions which have been linked (either directly, or indirectly) with vitamin D deficiency:
- Alzheimer’s disease/Dementia: The results of a study published in Neurology confirm a substantially increased risk for individuals with a deficiency to develop dementia or Alzheimer’s later in life (7).
- Erectile dysfunction: A study from the Journal of Sexual Medicine showed that a large proportion of men with ED had a deficiency in vitamin D (8).
- Schizophrenia: An article from the National Institutes of Health found a strong association between schizophrenia and low levels of vitamin D (9).
- Cardiac conditions: There may be a link with severe vitamin D deficiency and heart disease according to recent research (10).
Who’s At the Greatest Risk of Vitamin D Deficiency?
This deficiency is one of the most common in the world with more than one billion people affected (11). However, there are populations which are at a greater risk of developing this deficiency than others.
Older adults and breastfed infants are the two populations with the highest risk factors (12).
Other at-risk populations include people with dark skin, people with limited sun exposure, those with Inflammatory Bowel Disease (IBD), and people who are obese or who have undergone gastric bypass surgery (13, 14).
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Vitamin D and Hair Loss: The Link
The implications of a vitamin D deficiency can be severe. But did you know that such a deficiency may also play a role in hair loss?
Vitamin D plays an important role in the differentiation and proliferation of keratinocytes (15). Researchers from the University of Texas and sought to further understand the role of vitamin D in the process of anagen initiation as it relates to hair growth (16).
While the authors determine that the vitamin does play a significant role in the process of hair cycling, they suggest that more research is required on the potential regulation of vitamin D to successfully treat hair disorders.
But how exactly does it contribute to hair growth?
As mentioned, vitamin D is known to contribute to the proliferation of keratinocytes. One way in which it is known to do so is by its induction of keratinocyte growth factor.
Earlier studies available from the US National Library of Medicine determined that the use of keratinocyte growth factor promoted the survival of the hair follicle, which further supports the role of vitamin D in hair growth (17).
Another role vitamin D may play in hair loss is discussed in research from the Turkish Journal of Medical Science that measures the effects of hereditary vitamin D receptor deficiency on an individual’s hair growth (18).
This research determines that maintaining sufficient vitamin D levels in the blood reduces the likelihood of experiencing the effects of telogen effluvium. The study found that individuals that qualified for a diagnosis of telogen effluvium also showed a statistically significant difference in low levels of vitamin D in the blood.
Telogen effluvium is identified as a very common cause of diffuse hair loss by the Journal of Clinical & Diagnostic Research (19).
This condition is considered to be a period of hair loss following a triggering event, however there is the potential for chronic telogen effluvium to occur.
The resulting condition includes thinning hair, brittle and unhealthy hair, as well as hair that is easily dislodged from the scalp.
Vitamin D plays a significant role in supporting the physical processes related to hair growth, and it’s more directly involved through the development of keratinocytes.
If a body is dealing with a vitamin D deficiency, any one of these important processes might be interrupted and lead to issues of thinning hair and hair loss.
How You Can Increase Vitamin D Levels
The National Institutes of Health recommends ensuring healthy levels of vitamin D though the combination of diet, exposure to sunlight, and (if necessary) supplementation (20).
The human body is able to absorb vitamin D through skin that is exposed to sunlight or artificial sources of ultraviolet B (UVB) radiation. There are a variety of factors that impact the amount of vitamin D that can be obtained through UVB exposure including:
- The time of year
- The time of day
- The length of the day
- The angle of the sun
- Cloud cover
- Skin melanin content
- The use of sunscreen
Also there is evidence that sunlight can cause release of nitric oxide from the skin (21). Nitric oxide is a vasodilator which can reduce blood pressure and in the scalp may improve blood supply.
So while the absorption of vitamin D and the release of nitric oxide does occur with UV exposure, the dangers of UVB exposure should be taken into consideration (22). This is why it’s also a good idea to consider adding more foods high in vitamin D to your diet.
Foods High in Vitamin D
You can easily add these foods to your diet, and this will reduce your need for direct sun exposure (which comes with its own risks) and supplementation.
Vitamin D Supplements
It’s best to focus on increasing your dietary intake of vitamin D, though it can sometimes be difficult to hit your daily recommended value. In this case, you may want to consider a supplement.
This may also be particularly helpful during the winter months, or for those populations listed above who are at an increased risk of deficiency.
However, prior to adding a vitamin D supplement to your routine you should speak with your physician.
There is enough available evidence to suggest that a vitamin D deficiency can have significant negative impact on the body, including hair thinning and loss. And while it’s not likely that a deficiency in this nutrient is the only reason for your hair loss, it may be a significant contributing factor.
Maintaining a healthy diet rich in vitamin D and getting a safe amount of sunlight will help ensure optimal levels, but some people may require the use of available vitamin D supplements.
If you are experiencing hair loss, it may be best to consult with a medical professional about testing for – and potentially managing – a nutrient deficiency.