Vitamin D Supplementation Doesn’t Guarantee a Sunny Mood
Taking Vitamin D pills doesn’t seem to improve mood or prevent depression.
Posted Aug 04, 2020
Vitamin D is often referred to colloquially as the "sunshine vitamin." Previous studies have found that not getting enough sunlight exposure is linked to lower levels of vitamin D (25-hydroxyvitamin) in the blood; having a vitamin D deficiency is also associated with a higher risk of depression later in life. In their paper (Penckofer et al., 2010), "Vitamin D and Depression: Where Is All the Sunshine?" the authors write:
"The role that vitamin D supplementation could play in the prevention and treatment of depression has not been studied and should be an important area of future research. If exercising outdoors in the sunshine, eating foods rich in vitamin D, and/or taking dietary supplements to improve vitamin D deficiency could improve one's mental well being, it would be a simple and cost-effective solution for many who are at risk for depression and possibly other mental disorders."
Anecdotally, some people who spend a lot of time indoors and can't get natural sunlight exposure on a regular basis assume that taking vitamin D supplements may be a way to stay in a "sunshiney mood" and offset depression. But, until recently, there haven't been any large-scale randomized clinical trials to test whether or not vitamin D supplementation does, in fact, reduce depression risk.
Now, the results from a large, randomized clinical trial involving 18,353 middle-age and older adults (average age = 67.5 years) show that taking vitamin D supplements does not appear to reduce depression risk or boost mood.
This study was conducted by researchers from Harvard Medical School's Massachusetts General Hospital (MGH) and Brigham and Women's Hospital. According to the authors, their study's objective was "to test the effects of vitamin D supplementation on late-life depression risk and mood scores." The findings (Okereke et al., 2020) were published on August 4 in the journal JAMA.
When the Boston-based researchers began recruiting for this study in 2012, their research question was clear: "Can long-term supplementation with vitamin D prevent depression in the general adult population?" Eight years later, we have an answer to this question: "There was no significant benefit from the [vitamin D] supplement for this purpose. It did not prevent depression or improve mood," first author and principal investigator Olivia Okereke of MGH's Psychiatry Department said in a news release.
"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," Okereke said. "With nearly 20,000 people, our study was statistically powered to address this issue."
For this study, half the participants were given a vitamin D3 (cholecalciferol) supplement for an average of five years, while the other half of the group was given a placebo for the same period. All of the participants in this study did not show any clinically-relevant depressive symptoms or signs of depression at baseline, when the study began.
Notably, during the 5-year treatment period, the researchers did not find any statistically significant difference "in the incidence and recurrence of depression or clinically relevant depressive symptoms (hazard ratio, 0.97) or for change in mood scores" between those taking vitamin D supplementation and those taking a placebo. Based on these results, the authors conclude: "These findings do not support the use of vitamin D [supplementation] in adults to prevent depression."
"It's not time to throw out your vitamin D yet though, at least not without your doctor's advice," Okereke concluded. "Some people take it for reasons other than to elevate mood." Senior author JoAnn Manson of Brigham and Women's Hospital emphasized that "vitamin D is known to be essential for bone and metabolic health." But she also noted that "randomized trials have cast doubt on many of the other presumed benefits" of taking vitamin D supplements.
Olivia I. Okereke, Charles F. Reynolds III, David Mischoulon, Grace Chang, Chirag M. Vyas, Nancy R. Cook, Alison Weinberg, Vadim Bubes, Trisha Copeland, Georgina Friedenberg, I-Min Lee, Julie E. Buring, JoAnn E. Manson. "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 (First published: August 04, 2020) DOI: 10.1001/jama.2020.10224
Sue Penckofer, Joanne Kouba, Mary Byrn, and Carol Estwing Ferrans. "Vitamin D and Depression: Where is all the Sunshine?" Issues in Mental Health Nursing (First published online: May 07, 2010) DOI: 10.3109/01612840903437657