efficacy of food fortification with vitamin d in iranian adults: a systematic review and meta-analysis

There are a number of reports showing high prevalence of hypovitaminosis d across iran. the objective of this study was to evaluate whether food fortification with vitamin d has the potential to increase serum 25(oh)d concentrations in iranian people. medline, pubmed, embase, and the cochrane central register of controlled trials were searched for randomized controlled clinical trials involvingiranian participants to assess the effect of fortified food either with vitamin d2 or d3 (with or without calcium) versus control on serum 25(oh)d concentrations. four studies used dairy products as a food source and bread was used in one experiment. the daily dose of vitamin d3, 1000 and 2000 iu, and the duration of administration ranged from 8 to 12 weeks. the moderate heterogeneity was detected across the included studies (p<0.00001; i^2=55%).using a random effects analysis (n=193), the efficacy effect was 34.6nmol/l (95% ci: 28.6, 40.8). the present meta-analysis showed that food fortification with vitamin d could be an effective tool to prevent and control hypovitaminosis d and iranian population will most probably benefit from the vitamin d fortification as a national policy.