This post is part of our “AAFA Explains” series looking at complementary and alternative medicine aimed at asthma and allergies. The Asthma and Allergy Foundation of America (AAFA) wants to guide you as you decide between choices that may be “likely safe” or “potentially unsafe.”

In the past few years, researchers have found several possible links to health conditions and vitamin D deficiency. Most Americans have a deficiency. And those with asthma are more likely to be vitamin D deficient.

In a recent study¹, researchers looked at data from the National Health and Nutrition Examination Survey. They compared the vitamin D levels, current asthma diagnoses and lung function of about 11,000 children and more than 24,000 adults. After reviewing the data, researchers found that low levels of vitamin D were related to asthma diagnoses in children and adults. Low levels of vitamin D were also related to reduced lung function.

With all the benefits vitamin D is thought to have, can it help your asthma? Here’s what you need to know.

What Is Asthma?

Asthma is a chronic disease that causes airways to become inflamed (swollen), making it hard to breathe. There is no cure for asthma. People with asthma manage their disease by:

• Avoiding triggers
• Taking prescribed medicines
• Treating asthma episodes
  
  

Common symptoms of asthma are coughing, shortness of breath, wheezing and chest tightness. Asthma may lead to a medical emergency. If symptoms do not improve after following your Asthma Action Plan, call your asthma care provider or 911 right away. If you do not have an Asthma Action Plan, ask your asthma care provider so you know what to do and when to call for help.

What Is Vitamin D?

Vitamin D is an important vitamin that helps your body absorb calcium. It is often called the “sunshine vitamin.” Being out in the sun helps human skin make vitamin D.

What Does Science Say About Vitamin D and Asthma?

Research shows an important relationship between vitamin D deficiency and poor bone health. Scientists believe vitamin D may impact other areas of health, including asthma. According to research, vitamin D has antibacterial, antiviral and anti-inflammatory activity which might lower the risk of asthma attacks caused by respiratory infections.²

Here is a recent analysis of multiple studies that support the link between vitamin D and asthma:

Vitamin D for the Management of Asthma³

Researchers compared the results of nine studies. Seven included 435 children and two included 658 adults. They concluded that vitamin D is:

• Likely to reduce both the risk of asthma attack and health care use. But these findings were generally limited to only those with mild or moderate asthma. It also only looked at those with lower baseline vitamin D levels.
• Children and people with frequent severe asthma attacks were under-represented. More primary trials are needed to see if vitamin D can reduce the risk of severe asthma attacks in these groups.
  
  

What Does This Mean for People With Asthma?

If you have asthma, you may want to speak with your asthma care provider about checking your vitamin D levels. If you are deficient, talk to your provider to see if it might be worth trying a supplement.

Vitamin D is NOT an asthma treatment and NEVER replaces your prescription medicine. It will not make your lungs function better or treat day-to-day asthma symptoms. If you and your doctor decide you should take a vitamin D supplement, you must also take your prescribed asthma medicine. You should not take vitamin D with certain medicines, so talk to your doctor or pharmacist. Read package inserts to make sure there aren’t any interactions.

Scientists need to conduct more studies about vitamin D’s effects on children.

Is Vitamin D Safe?

Yes, in the appropriate dose. Ask your doctor about what amount is right for you and your health.

References
1. Han, Y., Forno, E., Celedón, J. (2016). Vitamin D Insufficiency and Asthma in a US Nationwide Study. The Journal of Allergy and Clinical Immunology: In Practice.
2. (Cochrane Database Syst Rev. 2016 Sep 5;9:CD011511. Vitamin D for the management of asthma. Martineau AR¹, Cates CJ, Urashima M, Jensen M, Griffiths AP, Nurmatov U, Sheikh A, Griffiths CJ.)
3. Martineau A.R., Cates C.J., Urashima M., Jensen, M., Griffiths, A.P., Nurmatov, U., Sheikh, A., Griffiths, C.J. (2016). Vitamin D for the management of asthma. Cochrane Library.

Medical Review April 2018.