Low Vitamin D and Depression Linked in Large Study
You may be familiar with the debate, which has been going on for years: do low levels of vitamin D cause or contribute to depression? While many small studies have provided conflicting results, a new large study of more than 12,000 people links low vitamin D with depression.
A vitamin D and depression link is important
Before you dash to the store to stock up on vitamin D supplements, Dr. E Sherwood Brown, the study’s senior author and professor of psychiatry at UT Southwestern Medical Center, noted that despite the importance of their findings, “we don’t have enough information yet to recommend going out and taking supplements.”
That being said, Brown and his colleagues, some of whom are with The Cooper Institute in Dallas, came to some other conclusions after evaluating the results of data from nearly 12,600 individuals, based on their findings.
Among those findings:
- Higher levels of vitamin D were associated with a significantly lower risk of current depression, especially among people with a history of depression
- Low levels of vitamin D were seen in individuals who had depressive symptoms, especially those who had a history of depression
Together these findings indicate that it may be helpful for healthcare providers to screen depressed patients for vitamin D levels, as well as screen for depression in people who have low levels of the vitamin.
Previous studies on vitamin D and depression
Although the authors of this current study did not determine the impact of taking vitamin D supplements or eating foods rich in vitamin D on depressive symptoms, a few other studies have done so, but with mixed results.
A University of Massachusetts study, for example, evaluated 81,189 members of the Women’s Health Initiative Observational Study who were 50 to 79 years when the study began. The investigators gathered information on food intake and supplement use and reported that overall, their findings supported a “potential inverse association of vitamin D, primarily from food sources, and depressive symptoms in postmenopausal women.”
A recent Australian study explored the impact of vitamin D supplementation on older women to prevent depressive symptoms. The participants were given either 500,000 IU vitamin D3 or placebo every autumn/winter for 3 to 5 consecutive years.
Overall, there were no significant differences in mental health or depressive symptoms between the two groups, even though vitamin D levels were 41% higher in the supplemented group compared with the placebo group after the women received their annual dose.
The current study on vitamin D
The new findings by researchers at UT Southwestern and The Cooper Institute provide more support for a link between low vitamin D levels and depression. Yet exactly what does this relationship mean?
- Do low vitamin D levels contribute to depressive symptoms?
- Does depression itself contribute to or cause lower vitamin D levels?
- Does vitamin D have an impact on neurotransmitters, such as serotonin, which has a major role in mood?
These are questions for which experts have not yet found answers. For now, however, it appears there is an association between low vitamin D and depression.
Vitamin D levels are often measured as part of a routine physical examination, and low vitamin D is recognized as a risk factor for many medical conditions, ranging from autoimmune diseases to heart problems, osteoporosis, and diabetes, among others. Depression may be yet one more item to add to the list.
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Hoang MT, Defina LF, Willis BL, Leonard DS, Weiner MF, Brown ES. Association between low serum 25-hydroxyvitamin D and depression in a large sample of healthy adults: the Cooper Center longitudinal study. Mayo Clin Proc 2011 Nov; 86(11): 1050-55
Sanders KM, Stuart AL, Williamson EJ, Jacka FN, Dodd S, Nicholson G, Berk M. Annual high-dose vitamin D3 and mental well-being: randomized controlled trial. Br J Psychiatry 2011 May; 198(5): 357-64