Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
Meta-Analysis
. 2020 Feb 3;19(1):11.
doi: 10.1186/s12937-020-0526-3.

The effect of vitamin D supplementation on hemoglobin concentration: a systematic review and meta-analysis

Seyed Mostafa Arabi  1 , Golnaz Ranjbar  1 , Leila Sadat Bahrami  1 , Mohammadreza Vafa  2 , Abdolreza Norouzy  3
Affiliations
Meta-Analysis

The effect of vitamin D supplementation on hemoglobin concentration: a systematic review and meta-analysis

Seyed Mostafa Arabi et al. Nutr J. .

Erratum in

Abstract

Aims: The purpose of this review was to investigate the effect of vitamin D supplements on hemoglobin concentration in subjects aged 17.5-68 years old; using randomized controlled trials (RCTs).

Methods: Relevant RCT studies were identified from January 2000 to January 2019 by using MeSH terms in PubMed, Embase, Cochrane Library, Clinical trials, Scopus databases and gray literature. The studies were reviewed systematically, and quality assessments were evaluated by the guidelines of the Cochrane risk of bias. The effect of vitamin D supplements (n = 14) on hemoglobin concentration was considered as primary outcome, while its effects on the levels of ferritin, transferrin saturation and iron status were derived as secondary outcomes. In total, 1385 subjects with age range of 17.5 to 68 years old were examined for 3 h to 6 months; Mean (standard deviation) or median interquartile changes in the hemoglobin concentration in each treatment group was recorded for meta-analysis.

Results: Fourteen RCTs met the inclusion criteria. Current study findings propose that vitamin D supplementation leads to a non-significant reduction in hemoglobin levels in subjects (17.5-68 years old) [std. mean difference (SMD): 0.01; 95% CI: - 0.28, 0.29; P = 0.95], also it has no significant effect on ferritin concentrations [std. mean difference (SMD): -0.01; 95% CI: [- 0.20, 0.18; P = 0.91]. However, vitamin D supplementation demonstrated positive effects on transferrin saturation [mean difference (MD): 1.54; 95% CI: 0.31, 2.76; P = 0.01] and iron status [std. mean difference (SMD): 0.24; 95% CI: - 0.09, 0.39; P = 0.002].

Conclusion: Current review concluded that supplementation with vitamin D had no significant effect on hemoglobin and ferritin levels while positive effects on transferrin saturation and iron status were observed. Further clinical studies are required to determine the actual effect of this intervention on hemoglobin levels.

Keywords: Anemia; Hemoglobin; Iron status; RCT; Vitamin D.

PubMed Disclaimer

Conflict of interest statement

The authors declare that they have no competing interests.

Figures

Fig. 1
Fig. 1
PRISMA flow-diagram of the study selection process
Fig. 2
Fig. 2
Forest plot showing results of a meta-analysis on the effects of vitamin D supplementation on hemoglobin. Data were reported as SMDs with 95% CIs. (Toxqui study at 4, 8, 12 and 16 weeks after intervention, Panwar study at 1, 4 and 6 weeks after supplementation)
Fig. 3
Fig. 3
Forest plot showing results of a meta-analysis on the effects of vitamin D supplementation on ferritin. Data were reported as SMDs with 95% CIs. (Toxqui study at 4, 8, 12 and 16 weeks after intervention, Panwar study at 1, 4 and 6 weeks after supplementation)
Fig. 4
Fig. 4
Forest plot showing results of a meta-analysis on the effects of vitamin D supplementation on transferrin saturation. Data were reported as MDs with 95% CIs. (Toxqui study at 4, 8, 12 and 16 weeks after intervention, Panwar study at 1, 4 and 6 weeks after supplementation)
Fig. 5
Fig. 5
Forest plot showing results of a meta-analysis on the effects of vitamin D supplementation on iron levels. Data were reported as SMDs with 95% CIs. (Toxqui study at 4, 8, 12 and 16 weeks after intervention, Panwar study at 1, 4 and 6 weeks after supplementation)
See this image and copyright information in PMC

Comment in

References

    1. De Benoist B, McLean E, Egli I, Cogswell M. Worldwide prevalence of anaemia 1993-2005. WHO global database on anaemia Geneva, Switzerland: World Health Organization; 2008. Nutr Clin Pract. 2008;23(2):128–141. doi: 10.1177/0884533608314536. - DOI - PubMed
    1. Kassebaum NJ, Jasrasaria R, Naghavi M, Wulf SK, Johns N, Lozano R, et al. A systematic analysis of global anemia burden from 1990 to 2010. Blood. 2014;123(5):615–624. doi: 10.1182/blood-2013-06-508325. - DOI - PMC - PubMed
    1. Zimmermann MB, Hurrell RF. Nutritional iron deficiency. Lancet. 2007;370(9586):511–520. doi: 10.1016/S0140-6736(07)61235-5. - DOI - PubMed
    1. Clark SF. Iron deficiency anemia: diagnosis and management. Curr Opin Gastroenterol. 2009;25(2):122–128. doi: 10.1097/MOG.0b013e32831ef1cd. - DOI - PubMed
    1. Hershko C, Hoffbrand AV, Keret D, Souroujon M, Maschler I, Monselise Y, et al. Role of autoimmune gastritis, Helicobacter pylori and celiac disease in refractory or unexplained iron deficiency anemia. Haematologica. 2005;90(5):585–595. - PubMed