Effect of Vitamin D supplementation and fortification strategies on serum Vitamin D levels: A systematic review and meta-analysis

Abstract

Background: Meta-analyses on effect of vitamin D intake of both vitamin D interventions (supplementation and fortification) on vitamin D status are lacking. Aim and Objectives: This study aimed to evaluate the effect of consuming Vitamin D fortified products and Vitamin D supplements on improving serum 25-hydroxyvitamin D in healthy people. Material and Methods: A systematic search was performed in three databases, including PubMed/Medline, Scopus, and Web of Science up to January 2024. The randomized controlled trials that compared the usage of Vitamin D supplements and Vitamin D-fortified products on levels of serum 25-hydroxyvitamin D were eligible for inclusion in this study. Studies that provided insufficient outcomes were excluded. Results: Meta-analysis was conducted using a random-effect model. Subgroup analysis was used to identify the sources of heterogeneity. The initial search strategy yielded 1,747 studies. After removing duplicates, a total number of six eligible articles were included in the meta analysis. Both Vitamin D supplementation [WMD: 35.67; 95% CI: (25.52, 45.82); P < 0.001; (I = 96.4%, P < heterogeneity 0.001) and Vitamin D fortification [WMD: 34.84; 95% CI: (25.91, 43.78); P < 0.001; (I = 98.4%, P < 0.001)] heterogeneity significantly increased serum 25-hydroxyvitamin D levels. The results did not change based on the study location, duration, type of vehicle, dose of the fortification, gender, and number of participants' subgroups. Conclusion: Both Vitamin D fortification and Vitamin D supplementation can significantly increase 25-hydroxyvitamin D concentration. Policymakers might use these findings to tackle Vitamin D deficiency through supplementation and food fortification strategy.

Keywords

• vitamin d
• deficiency
• supplementation
• food fortification
• meta-analysis