Effects of vitamin D supplementation on neuroplasticity in older adults: a double-blinded, placebo-controlled randomised trial
Low-Dose Vitamin D Prevents Muscular Atrophy and Reduces Falls and Hip Fractures in Women after Stroke
The negative article here:
But the trial, published in JAMA Cardiology, is also not the last word on the subject and leaves open the possibility that vitamin D may be found beneficial in the future for cardiovascular disease or other indications.
After 3.3 years of follow-up, cardiovascular disease occurred in 11.8% of participants in the vitamin D group and in 11.5% in the placebo group. The results were similar in the important subgroups of participants with vitamin D deficiency at baseline and in those with previous cardiovascular disease.
The study used higher overall doses than used in many previous studies, which had been criticized for this potential weakness. A random sample of 438 participants in the study showed that 25(OH)D levels were 20 ng/mL higher in the treatment group, reaching optimal levels as suggested by observational studies. The authors acknowledged that there are questions whether the monthly dosing of vitamin D results in persistent increases in vitamin D levels.
Erin Michos (Johns Hopkins) commented that “the evidence supports that generally healthy people should not take vitamin and mineral supplementation for CVD prevention, and that includes Vitamin D.” She said the large on-going VITAL study, with more than 25,000 participants, will provide much more clarity on the effects of vitamin D supplements on heart disease, cancer, and other endpoints. But Michos said she suspects that VITAL will also be a negative trial, “especially since vitamin D deficiency was not an enrollment criteria. That likely will be the end of the era of enthusiasm for use of vitamin D for preventing all chronic ills.”
“I am a strong believer that IF supplementation might help anyone (and that is a big if), it likely would be only among individuals with deficiency,” said Michos. “MORE IS NOT BETTER, and people with adequate vitamin D stores do not need supplementation.” She pointed out that, although there was no signal of benefit in the group with low vitamin D levels at baseline, the trial was not powered to detect differences. She speculated that supplements might also be found helpful in people with severe vitamin D deficiencies, such as below 15 ng/mL.