Calcium and vitamin D intakes in children: a randomized controlled trial

BACKGROUND Calcium (Ca(2+)) and vitamin D (VitD) play an important role in child health. We evaluated the daily intake of Ca(2+) and VitD in healthy children. Moreover, we demonstrate the efficacy of Ca(2+) and VitD supplementation. METHODS Daily Ca(2+) and VitD intake was evaluated in consecutive healthy children through a validated questionnaire. Subjects with <70% of dietary reference intakes (DRIs) of Ca(2+) and VitD were invited to participate in a prospective randomized trial with 2 groups of nutritional intervention: Group 1, dietary counseling aiming to optimize daily Ca(2+) and VitD intake plus administration of a commercially available Ca(2+) and VitD supplementation product; Group 2, dietary counseling alone. At the enrollment (T0) and after 4 months (T1) serum 25(OH) Vitamin D levels were assessed. RESULTS We evaluated 150 healthy children (male 50%, mean age 10 years); at baseline a low VitD intake was observed in all subjects (median 0.79 μg/die, IQR 1.78; range 0.01-5.02); this condition was associated with Ca(2+) intake <70% of the DRIs in 82 subjects (55%). At baseline serum 25(OH)D levels were low (<30 ng/ml) in all study subjects and after 4 months of nutritional intervention, a normalization of serum 25(OH)D levels (≥30 ng/ml) was observed in all children in Group 1 and in only one subject in Group 2 [Group 1: T1 33.8 ng/ml (IQR 2.5) vs Group 2: T1 24.5 ng/ml (IQR 5.2), p <0.001]. CONCLUSIONS Adequate Ca(2+) and VitD intakes are difficult to obtain through dietary counseling alone in pediatric subjects. Oral supplementation with of Ca(2+) and VitD is a reliable strategy to prevent this condition. TRIAL REGISTRATION The study was registered in Clinical Trials Protocol Registration System (ID number: NCT01638494).