Does Lack of Vitamin D Cause Asthma?

by John Bottrell Health Professional

Surely we know the sun supplies us with an ample supply of vitamin D, the sunshine vitamin.
So is it possible lack of sun exposure may cause asthma, or make it more severe?
We shall investigate the evidence.

John Grever, in his post "Vitamin D Deficiency Linked to Asthma Severity," at Medpage Today reports that most researchers agree that we get little vitamin D from our diets, so we rely on the sun for our vitamin D supply.

However, poor diet can also result in low levels of vitamin D, as the vitamin can be obtained by the intake of dairy products such as cheese and milk, fatty fish, fish oils, and fortified foods like cereal., "Vitamin D Levels Linked to Asthma Severity," reports that 90 percent of our vitamin D "is produced by the body in resonse to sun exposure." This is why it's called the sunshine vitamin.

So, possible causes of low Vitamin D are:

  • Lack of exposure to the sun

  • Sunscreen use

  • Inadequate dietary intake

  • Increased time spent indoors (a modern dilemma)

Clifford Basset in his Fox News report, "Can Vitamin D Improve Lung Function, in Asthma?" reports that researchers evaluating five decades of studies learned that as many as a third of all children and adolescents in the U.S have low vitamin D levels, and this deficiency is more common in western nations like the U.S. and Europe.

The Journal of Allergy and Clinical Immunology, "Is vitamin D deficiency to blame for the asthma epidemic?" (November 2007, 120, 5, page 1031), reports on one study that links low vitamin D levels in pregnant mothers with a 40 percent greater risk of their children developing asthma.

Researches surmise that vitamin D is essential for adequate development of the immune system. Since asthma is a condition caused by an overactive immune system, the link is evident.

The Daily News and Analysis, "Lack of Vitamin D linked to airway changes in children with asthma," reports on a study that shows a link between low vitamin D and worsening lung function and the need for an increased need for systemic steroids.

The theory here is that lack of vitamin D causes the muscles lining the air passages of the lungs (bronchioles) to become enlarged or inflammed.

Healthsout reporter Steven Reinberg, in his post "Too Little Vitamin D May Worsen Asthma," reports on a study that shows low levels of vitamin D nearly doubled the inflammatory response. This resulted in worse asthma and asthma less responsive to steroids in people with insufficient vitamin D levels.

He writes that researchers evaluating the report surmise that low levels of vitamin D increases "production of the pro-inflammatory cytokine, TNF-alpha.
This raises the possibility that low low vitamin D levels are tied to increased inflammation of the airways."

On a similar note, Jonathan Corren, "Asthma Phenotypes and Endotypes, An Evolving Paradigm for Classification," explains that vitamin D may regulate immune cell response to corticosteroids.
So ack of the vitamin may prevent corticosteroid therapy from being effective.
The inability to treat with this top-line asthma medicine may cause Severe Asthma.

The American Journal of Respiratory and Critical Care Medicine, "Serum Vitamin D Levels and markers of Severity of Childhood Asthma in Costa Rica," (2009, vol. 179, pages 765-771) also reports on a study that linked vitamin D insufficiency with severe or worsening asthma.

The study also shows that vitamin D supplementation may help get vitamin D levels back to normal, and this helps get asthma back under control.

Yet other researchers believe that your body doesn't get enough vitamin D from supplementation to make up for insufficient vitamin D due to lack of exposure to sunlight.

Many asthma experts now classify Vitamin D Deficiency as an asthma subtype. This allows researchers to tailor treatment guidelines specifically for these patients.

One treatment option, obviously, may be Vitamin D supplementation. Since the efficacy of this is still unknown, and since low vitamin D may result in steroid resistance, aggressive treatment with alternative medicines may also be required.

Finding what medicine works best may be a matter of trial and error, and it may take some time.
It will also require working closely with a physician, and being very compliant with treatment regimes.

Other experts believe the vitamin D and Asthma link is a mere coincidence.
They site that asthmatics are more likely to spend time indoors.
They also site that a low vitamin D may simply coincide with other vitamins, minerals, processes or elements that are essential for proper immune function.

Regardless, there is definitely a link between asthma and vitamin D. Whether or not the vitamin actually causes or triggers asthma is still open to debate, and further studies will be needed.
What do you think?

John Bottrell
Meet Our Writer
John Bottrell

John Bottrell is a registered Respiratory Therapist. He wrote for HealthCentral as a health professional for Asthma and Chronic Obstructive Pulmonary Disease (COPD).