A new randomized controlled trial published in the Journal of Clinical Diagnostic Research found that vitamin D supplementation significantly improved stroke outcome.
Stroke is the second leading cause of death worldwide and the number one cause of serious, long-term disability in the United States. An estimated 15 million people worldwide suffer a stroke each year.
Ischemic stroke accounts for about 87 percent of all stroke cases. Ischemic strokes occur when a blood clot blocks a blood vessel in the brain, preventing blood from flowing to the brain. Within minutes, brain cells begin to die.
Research has found that vitamin D deficiency is associated with ischemic stroke along with contributing factors, such as hypertension, heart disease and diabetes. Furthermore, a study found that ischemic stroke patients with the highest vitamin D levels had better functional outcomes at three months than those with the lowest vitamin D levels.
Although research has shown an association between vitamin D deficiency and stroke, studies have not evaluated the effects of vitamin D supplementation in ischemic stroke patients. Therefore, researchers from India recently conducted a randomized controlled trial to test the hypothesis that vitamin D supplementation leads to improved functional outcome in ischemic stroke patients compared with ischemic stroke patients receiving only conventional treatment.
A total of 66 ischemic stroke patients with vitamin D levels below 30 ng/ml were enrolled into the study, with average vitamin D levels of 18.2 ng/ml. All patients were between the ages of 50 and 80 years old.
Half of the patients received only conventional treatment. The other half received one 6 lac IU cholecalciferol (vitamin D3) injection along with conventional treatment. The researchers chose to use one vitamin D injection opposed to oral supplementation to avoid problems of compliance. A prior study found that 6 lac IU cholecalciferol injections led to vitamin D sufficiency in previously deficient individuals.
The researchers used the long term Scandinavian Stroke Scale (SSS) to assess the severity of ischemic stroke before and after three months. The long term SSS evaluates motor function, orientation and language. Low scores suggest more severe ischemic stroke.
The researchers found that the average SSS score improved by 6.39 points in the patients who received vitamin D; whereas, the average SSS score only improved by 2.50 points in those who did not receive vitamin D (p < 0.001). This indicated that vitamin D significantly improved stroke recovery.
The researchers concluded,
“Vitamin D is a potential risk factor for stroke and vitamin D supplementation has better outcome in ischemic stroke patients with vitamin D deficiency.”
They went on to state,
“Screening for vitamin D status is essential in ischemic stroke patients and supplementation [should] be done to maintain vitamin D at normal levels.”
The study possessed a few limitations. First, the study used one intramuscular dose of vitamin D. Response to cholecalciferol injections is not uniform in patients, which can result in improper doses being administered. Furthermore, the researchers did not assess vitamin D levels after the patients received the injection; therefore, we cannot be certain that all patients achieved vitamin D sufficiency. The Vitamin D Council recommends daily vitamin D supplementation to closely mimic the daily sun exposure that our ancestors received.
Another study limitation was the relatively small sample size. Lastly, although the study followed a randomized controlled trial design (the gold standard of research), the control group did not receive a placebo pill. Therefore, some of the benefits experienced by the vitamin D group may have been caused by the placebo effect. Nevertheless, the study presented strong findings that elicit further randomized controlled trials.
Tovey, A. & Cannell, JJ. Vitamin D may aid in recovery from stroke. The Vitamin D Council Blog & Newsletter, May, 2017.