According to a recent US study, taking vitamin D doesn’t keep knee pain from getting worse or slow the loss of cartilage for people with osteoarthritis.
Researchers from Tufts Medical Center in Boston randomly assigned 156 patients with knee osteoarthritis to take 2,000 IU vitamin D/daily or a placebo for 2 years. For some patients, the vitamin D doses increased to as high as 8,000 IU in order to raise vitamin D levels above 36 ng/ml.
The authors report the mean vitamin D blood level rose in the treatment group from 22.7 to 38.5 ng/ml, compared with 21.9 to 24.7 ng/ml in the placebo group.
On a 0-20 point pain scale, researchers found that people taking vitamin D saw a 2.3 point decrease over the two year study, compared to a 1.5 point decrease among those taking placebos. Knee cartilage volume, often used as a marker for osteoarthritis progression, was also similar between the two groups.
Robert Heaney, MD, a leading scientist in the vitamin D field, was not surprised by the study results.
“It’s almost certain that vitamin D’s effects are different from person to person. It’s very important for some people, but may not make any difference for others,” he told Reuters Health.
Heaney pointed out that it’s worth continuing the research since vitamin D may have other health benefits.