RESUMEN
BACKGROUND: There is limited randomized controlled trial evidence to support the association between vitamin D deficiency and anemia risk, highlighting the necessity for further investigations into the role of vitamin D in influencing iron status. OBJECTIVE: The aim of this study was to determine the effect of vitamin D3-fortified fruit drink consumption (4,000 IU) on vitamin D and iron status biomarkers among iron-deficient women (serum ferritin of <20 µg/L [to convert µg/L ferritin to ng/mL, multiply by 1]). DESIGN: An 8-week double-blind randomized controlled trial was conducted. SUBJECTS/SETTING: A total of 45 healthy, nonpregnant, nonlactating subjects aged 18 through 40 years (mean [SD] 25.3 [4.6] years) were included in the study, excluding those who donated blood 6 months prior, regularly consumed nutritional supplements, or had gastrointestinal or iron metabolic disorders. INTERVENTION: Subjects were randomly assigned to receive either vitamin D3-fortified fruit drink or a placebo. MAIN OUTCOME MEASURES: Measurements of 25-hydroxyvitamin D (25[OH]D), serum ferritin, high-sensitivity C-reactive protein, and full blood count concentrations were obtained at baseline, interim, and post intervention. STATISTICAL ANALYSES: A mixed model, repeated measures analysis of variance was used to analyze the intervention effect. RESULTS: Attrition rate for the study was 13%, with 6 dropouts, and 39 subjects completed the study. Daily consumption of vitamin D3-fortified fruit drink in the intervention group resulted in significant increases in 25(OH)D and serum ferritin concentrations compared with the placebo group. The intervention group showed significantly higher mean (SD) changes (Δ) in both 25(OH)D (Δ 76.4 [30.2] nmol/L [to convert nmol/L 25(OH)D to ng/mL, multiply by .4] vs Δ -1.3 [10.7] nmol/L; P = .001) and serum ferritin concentrations (Δ 2.2 [4.2] µg/L vs Δ -0.3 [3.4] µg/L; P = .048) between baseline and post intervention. The other iron status biomarkers were not affected by the intervention. CONCLUSIONS: Our study found that daily vitamin D3-fortified fruit drink supplementation for 8 weeks effectively improved 25(OH)D and iron stores, indicated by increased serum ferritin concentrations, in iron-deficient women. Further research is needed to evaluate its safety, efficacy, feasibility, and optimal food fortification in diverse populations.
RESUMEN
BACKGROUND: In recent years, emerging evidence has highlighted the role of vitamin D as an iron absorption enhancer by suppressing hepcidin concentration, albeit with an unclear underlying mechanism. Dietary-based approach in improving iron status has been widely practised, however, there is a scarcity in randomized controlled trials (RCT) to elucidate the effect of vitamin D-fortified juice on iron status recovery. Therefore, this study aims to investigate the effect of an 8-week vitamin D3-fortified fruit juice supplementation on iron status indicators in childbearing-aged women with marginally low iron stores. METHODS: In a placebo-controlled, double-blind, RCT, a total of 120 women aged between 19-40 with serum ferritin < 20 µg/l and fulfilled the eligibility criteria will be randomized into consuming either vitamin D3-fortified fruit juices containing 4000 IU (100 mcg) (vitamin D) or placebo-fruit juices (placebo) daily for eight weeks. At every 4-week interval, 10 ml fasting blood sample, information on dietary habit and anthropometric measurement will be collected. A mixed model repeated-measures analysis of variance will be performed to determine the effect of the intervention and the interaction with time points for all iron and vitamin D status blood biomarkers. DISCUSSION: Vitamin D supplementation in food fortification as a novel iron absorption enhancer might be a future and relevant alternative management of iron deficiency as opposed to the oral iron therapy that has poor adherence. TRIAL REGISTRATION: Clinicaltrials.gov: registration number NCT04618289, registration date October 28, 2020, protocol ID JKEUPM-2020-033.