Addition of vitamin D to asthma treatment has limited benefits and it does not help in controlling symptoms of the breathing disorder, a new study finds.
Vitamin D deficiency has been linked to a host of illnesses like Osteoporosis, cancer, heart diseases, obesity, diabetes, high blood pressure and asthma. Previous studies have found that low levels of vitamin D in asthma patients puts them at a higher risk of incurring severe lung damages. Hence, a team of researchers conducted a study to see whether the addition of vitamin D supplements to asthma treatments could do any good. They were disappointed to find that vitamin D supplements offered limited benefits.
"Previous studies suggested that if you have asthma and low levels of vitamin D in the blood, you have worse lung function, more asthma attacks and more emergency room visits than asthma patients with higher vitamin D levels," said Mario Castro, lead author of the study, in a press statement. "This is the first randomized controlled trial to investigate whether taking vitamin D supplements can improve asthma control."
For the new study, researchers examined the medical reports of 408 adult patients from nine major U.S. medical centers. All the patients were diagnosed with mild to moderate asthma and had vitamin D deficiency. Vitamin D level below 30 is considered abnormal and the patients had an average of 18 nanograms per milliliter of blood. Researchers also noted that all patients took an inhaled steroid daily to control their asthma, and all had rescue inhalers in the event of an asthma attack.
The patients were divided into two groups. The treatment group received a loading dose of 100,000 international units of vitamin D3 followed by daily doses of 4,000 units, while the placebo group received identical looking but inactive vitamin D capsule. Researchers didn't observe any difference in asthma control between the participants of both groups. There was also no major difference in the number of treatment failures requiring patients to take more medication. Researchers also noted no difference in the number of asthma attacks or in their need for emergency care.
However, researchers did find that the treatment group was able to reduce the amount of inhaled steroid they took daily to control their asthma.
"The difference was small - 15 micrograms of steroid per day - but statistically significant," said Castro, who treats patients at Barnes-Jewish Hospital. "Over the long term, even that small amount may have an important impact on reducing side effects of inhaled steroids. Although inhaled steroids work very well in controlling asthma, patients don't like them because they cause weight gain and increase the risk of diabetes and high blood pressure. Anything we can do to reduce the amount they need is important."
Researchers also said that despite taking large doses of vitamin D supplements, not all patients were able to achieve the required level of the nutrient. At the end of the study, 18 percent of patients belonging to the treatment group still had vitamin D levels below 30. Those that did achieve the required level had a 40 percent decrease in treatment failure.
"We're encouraged by this result, but we have to be careful," Castro said. "Our study was designed to look at the entire group that received vitamin D supplements, not just those who achieved higher levels of vitamin D in the blood. We need more studies looking at this question. But I am paying attention to vitamin D levels in my patients.
Many of the previously touted benefits of vitamin D have been questioned lately. A study conducted in March this year noted that the vitamin is not effective in reducing depression risks, debunking previous beliefs. Another study found no concrete evidence to suggest that vitamin D supplements are effective in preventing accidental falls in older people.
In January this year, University of Auckland researchers released a controversial report suggesting healthy people may not benefit as much from Vitamin D as it doesn't have a significant effect on preventing heart attacks, stroke, cancer or bone fractures in such people.
In another report, the U.S. National Cancer Institute noted that its studies conducted on the effects of vitamin D on cancer may not be completely accurate because studying a person's blood vitamin level at a single point in time, as many studies do, may not give an accurate picture of his or her true levels. Moreover, many studies don't use high enough doses to see the benefits.
Despite this, various studies and health experts continue to vouch for the health benefits of vitamin D and how it can help in keeping serious health issues at bay. Very recently, Northwestern University researchers said that vitamin D can help reduce the risk of aggressive prostate cancer in men.
The current study was funded by the National Heart, Lung and Blood Institute (NHLBI) of the National Institute of Health. Findings were published online in the journal JAMA.
