Vitamin D supplementation may help to alleviate symptoms of depression


An extensive meta-analysis suggests that vitamin D supplementation may alleviate depressive symptoms in adults with depression. Conducted by an international team of researchers, the meta-analysis includes dozens of studies from around the world.

Depressive symptoms cause a significant disease burden worldwide. The therapeutic efficacy of current antidepressants is often insufficient, which is why further ways to alleviate the symptoms of depression have been sought, for example, from nutritional research.

Vitamin D is believed to regulate central nervous system functions the disturbances of which have been associated with depression. In addition, cross-sectional studies have observed an association between depressive symptoms and vitamin D deficiency.

However, previous meta-analyses on the effects of vitamin D supplementation on depression have been inconclusive. In a meta-analysis, results from several different studies are combined and analyzed statistically.

The new meta-analysis on the association of vitamin D supplementation with depression is the largest one published so far, including results from 41 studies from around the world.

These studies have investigated the efficacy of vitamin D in alleviating depressive symptoms in adults by randomized placebo-controlled trials in different populations.

The studies included those carried out in patients with depression, in the general population, and in people with various physical conditions.

The results of the meta-analysis show that vitamin D supplementation is more effective than a placebo in alleviating depressive symptoms in people with depression. There were major differences in the vitamin D doses used, but typically the vitamin D supplement was 50–100 micrograms per day.

“Despite the broad scope of this meta-analysis, the certainty of evidence remains low due to the heterogeneity of the populations studied and the due to the risk of bias associated with a large number of studies,” Doctoral Researcher and lead author Tuomas Mikola of the Institute of Clinical Medicine at the University of Eastern Finland says. The meta-analysis is part of Mikola’s Ph.D. thesis.

“These findings will encourage new, high-level clinical trials in patients with depression in order to shed more light on the possible role of vitamin D supplementation in the treatment of depression,” Mikola concludes.

The meta-analysis was published in Critical Reviews in Food Science and Nutrition and carried out in international collaboration between Finnish, Australian and U.S. researchers.

Vitamin D is considered to be a crucial nutrient for calcium absorption and homeostasis, thus influencing bone health and metabolism [1]. However, several investigations in the last few decades have revealed that this vitamin is associated with numerous extra-skeletal effects [2] and that it plays a pivotal role in the prevention and treatment of multiple diseases [3].

Taking this into account, the serious public health problem appeared, as vitamin D insufficiency is estimated to affect about 50% of the global population, and vitamin D deficiency affects 1 billion people, independent of their age and ethnicity [4]. This problem was addressed in a prominent meta-analysis conducted by Garland et al. [5], which demonstrated that low serum levels of 25-hydroxyvitamin D (25(OH)D) are associated with an increased rate of all-cause mortality.

This finding prompted other authors to provide recommendations to protect the global population from deficiency by increasing the recommended vitamin D intake levels [6], as well as applying fortified products and through supplementation [7].

The results of prospective clinical trials presenting the effects of vitamin D supplementation are promising, indicating that it is a valuable nutrient, especially for individuals who are unable to meet the recommended dietary intake levels and are unable to receive an adequate amount of sunlight [8].

The most important results indicated that combined supplementation with calcium and vitamin D reduces the risk of total cancer, breast cancer, and colorectal cancer, which was found in Women’s Health Initiative (WHI) [9]. Similarly, a population-based, double-blind, randomized placebo-controlled trial by Lappe et al. [10] reported that combined calcium and vitamin D supplementation reduces all-cancer risk in postmenopausal women.

At the same time, a systematic review and meta-analysis of randomized controlled trials by Jolliffe et al. [11] showed that vitamin D supplementation reduces the rate of moderate-to-severe chronic obstructive pulmonary disease (COPD) exacerbations in patients with low baseline 25(OH)D levels. Some studies indicated that vitamin D supplementation may reduce the risk of infection by SARS-CoV-2 and, thus, coronavirus-19 disease (COVID-19) and may also complement the applied treatment, but more studies are necessary to consolidate this theory [12]. Vitamin D supplementation may be needed to obtain and maintain the desirable blood levels of 25(OH)D [13], but the specific doses depend on the target group [14].

Vitamin D is found to be important not only for physical health problems but also to address various mental health issues, as suggested by some meta-analyses conducted mainly for depression. The meta-analyses by Vellekkatt and Menon [15], Shaffer et al. [16], and Spedding [17], concluded that vitamin D supplementation may effectively alleviate the symptoms of depression.

However, the results are not consistent, as the meta-analyses by Gowda et al. [18] and Li et al. [19] presented contradictory results and reported that vitamin D does not improve the symptoms of depression, which may be explained by the fact that the studies in this meta-analyses included individuals with low levels of depression symptoms and adequate baseline 25(OH)D levels [18], as well as the publications reviewed were characterized by a high risk of bias [19].

The positive effect of vitamin D supplementation was also associated with a reduction in the occurrence of negative emotions, as indicated in the meta-analysis by Cheng et al. [20], and for improvement of quality of life, as indicated in the systematic review by Hoffmann et al. [21].

Despite the fact that some systematic reviews and meta-analyses evaluated the influence of vitamin D supplementation on some aspects of mental health, namely, symptoms of depression [15,16,17,18,19], negative emotions [20], and quality of life [21], its effect on other mental health problems has not been investigated so far, although some single studies addressed this issue. Therefore, the aim of the present study was to evaluate the influence of vitamin D supplementation on mental health in healthy adults.

reference link :

Original Research: Closed access.
The effect of vitamin D supplementation on depressive symptoms in adults: A systematic review and meta‐analysis of randomized controlled trials” by Tuomas Mikola et al. Critical Reviews in Food Science and Nutrition


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