Effects of vitamin D supplementation in endometriosis: a systematic review

Abstract

Background There is a growing body of human, animal and in vitro studies on vitamin D (vit D) substitution in endometriosis. The aim of this systematic review is to critically appraise and qualitatively synthesize the results of the available studies that examine the supplementation of vit D for endometriosis treatment. Methods A systematic search of the literature was conducted in four electronic databases (Medline, Cochrane, Scopus, Embase) and grey literature for original research articles on humans, animals and in vitro models published in any language. Results Four human studies, four animal studies and four in vitro studies were included. Quantitative synthesis of human studies showed no significant effect of vit D intake for dysmenorrhea (2 studies, 44 vit D vs 44 placebo, mean -0.71, 95% CI -1.94, 0.51) and non-cyclic pelvic pain (2 studies, 42 vit D vs 38 placebo, mean 0.34, 95% CI -0.02, 0.71). Regarding reproductive outcomes in women with endometriosis after in vitro fertilization, the only available study showed no differences between women taking vit D and women taking placebo. Three of the four included animal studies showed regression of endometriotic implants when treated with vit D. The in vitro studies demonstrated that vit D decreases invasion and proliferation of endometriotic lesions without affecting apoptosis. Conclusions Although in vitro and animal studies suggest regression of the endometriotic implants and decrease of invasion and proliferation after vit D supplementation, this was not reflected in the results of the meta-analysis, which showed no benefit of vit D supplementation in patients with endometriosis and dysmenorrhea or non-cyclic pelvic pain as well as on the outcome of IVF treatment. However, given the heterogeneity and the diversity of the available studies, more research is required to shed light on the role of vit D supplementation in women with endometriosis.

The Role of Selected Dietary Factors in the Development and Course of Endometriosis

“…There are, however, studies that do not support the above reports [128,129]. Further, data on the regression of endometriosis with vitamin D still need to be more conclusive because significant differences are observed in the results obtained in cell studies and animal models compared to the effects of vitamin D use by women [130,131]. The results of a case-control study by Buggio et al [132] did not confirm an association between serum 25-hydroxyvitamin D levels and the different phenotypes of endometriosis.…”

Vitamin Effects in Primary Dysmenorrhea

“…We note, however, that these animal models have been used in experimental procedures involving other supplements such as essential oils [62]. Interestingly, animal models of endometriosis have been investigated thoroughly, in terms of vitamin effects, revealing positive results in alleviating symptoms following the administration of Vit D [63]. Considering the fact that endometriosis is the most common cause of secondary dysmenorrhea [64], it can be strongly hypothesized that Vit D administration may also have beneficial effects on primary dysmenorrhea.…”

Endometriosis – a painful disease

“…In addition, although dietary approaches are quite commonly recommended for EAP, there is little evidence to support these. Interestingly, a recent systematic review of the effects of vitamin D supplementation in endometriosis found that whilst in animal and in-vitro trials, there was a regression in lesions, this did not translate to a reduction in pain scores in clinical studies [37]. It will be interesting to see how other supplements, similarly, informed by robust basic science, translate to clinical effect (e.g.…”