Chronic obstructive pulmonary disease (COPD) is a crippling combination of chronic bronchitis and emphysema. If you have it, you’re worn out by a constant cough, phlegm, shortness of breath and chest tightness. The symptoms can be managed (though never cured) by breathing exercises and physical therapy, bronchodilator and corticosteroid drugs and—worst-case scenario—being hooked up to an oxygen tank. And every so often, symptoms will flare up to an extreme.

Breakthrough news: If you or a loved one is a COPD sufferer, taking supplements of a certain essential nutrient can significantly reduce your risk of flare-ups.


Researchers from Queen Mary University of London expanded on a small study that looked at vitamin D deficiency and supplementation in people with COPD and confirmed the earlier findings—vitamin D supplements reduced risk of flare-ups.

The current study recruited 240 patients with COPD from across Britain and conducted a full-fledged placebo-controlled study.

The researchers first tested these patients’ current vitamin D levels to keep track of who was low, normal or high. Then, about half the participants were treated with a 3-milligram dose (120,000 IU) of vitamin D, taken in the form of oral drops given every two months for a year. (This is a very large megadose of the vitamin that is, basically, only used in research studies and in people with severely low vitamin D levels. The average person should never take this amount of the vitamin on his or her own.) The other participants were given a placebo.

The results: Supplementation reduced the risk of COPD flares by 43% in patients who had borderline-to-low vitamin D levels to begin with (blood levels of less than 50 nanomoles per liter [nmol/L]) but did not do much for patients who already had normal or high levels of the vitamin (blood levels of 50 nmol/L or greater). But most people with COPD do have low levels of vitamin D or outright vitamin D deficiencies. In this study, 87% had insufficient-to-deficient levels.

The researchers are not yet sure exactly how vitamin D helps stop COPD flare-ups, but they think it might have to do with the vitamin’s protective antimicrobial and anti-inflammatory properties. COPD flares often are caused by either infections or irritation of the respiratory system (from exposure to cigarette smoke or other pollutants, for example). Vitamin D likely helps the immune system fend off these onslaughts.


Although no serious side effects were attributed to vitamin D in the study, more D was not better. In fact, patients who already had vitamin D blood levels of 100 nmol/L or greater were slightly more susceptible to flares. So, even though the large majority of people with COPD are low in D and could use a supplement, don’t just start taking it on your own. Instead, speak to your doctor about having a blood test to know exactly what your vitamin D level is before starting a supplement.

Having too much vitamin D  in your system is dangerous. It can cause itchy skin, calcium buildup in the arteries, daytime sleepiness, headaches, heart rhythm abnormalities, muscle pain, stomach issues, kidney stones, and high blood pressure.

If your vitamin D level is very low, your doctor may prescribe a very large dose of D that you take, for example, once a week or once a month—as the patients in this study did. But this is definitely not a regimen that anyone should do on his or her own without close medical supervision for the reasons explained above.

More than likely, your levels are just a bit low, and your doctor will recommend a high-quality daily supplement in a dosage that is right for you. The recommended daily allowance of vitamin D for people who are one to 70 years of age is 600 IU, and it’s 800 IU for people 71 and older…but up to 4,000 IU per day has been considered safe by the US National Academy of Sciences Institute of Medicine.