Despite previous studies that suggested a link between low levels of vitamin D and heightened depression risk, long-term vitamin D supplementation does not protect against depression in the general adult population, according to a large, randomized clinical trial published in JAMA.
“There was no significant benefit from the supplement for this purpose. It did not prevent depression or improve mood,” said principal investigator and lead author Olivia I. Okereke, MD, of the psychiatry department at Massachusetts General Hospital in Boston.
The study spanned 18,353 men and women aged 50 years and older without depression or clinically relevant depressive symptoms: 9181 were randomized to vitamin D3 and 9172 to placebo over an average 5 years.
“One scientific issue is that you actually need a very large number of study participants to tell whether or not a treatment is helping to prevent development of depression,” Dr. Okereke said. “With nearly 20,000 people, our study was statistically powered to address this issue.”
The study revealed the incidence and recurrence of depression or clinically relevant depressive symptoms was not significantly different between participants who received vitamin D3 and participants who received placebo. Mood scores on the 8-item Patient Health Questionnaire depression scale did not significantly differ between treatment groups either.
The findings, researchers concluded, do not support the use of vitamin D3 supplementation to prevent depression in adults.
However, “it's not time to throw out your vitamin D yet though, at least not without your doctor's advice,” Dr. Okereke said.
“Vitamin D is known to be essential for bone and metabolic health,” added study senior author, JoAnn Manson, MD, DrPH, of Brigham and Women’s Hospital, Boston, Massachusetts, “but randomized trials have cast doubt on many of the other presumed benefits.”
Okereke OI, Reynolds CF III, Mischoulon D, et al. Effect of long-term vitamin D3 supplementation vs placebo on risk of depression or clinically relevant depressive symptoms and on change in mood scores: a randomized clinical trial. JAMA. 2020;324(5):471-480.