Effect of Micronutrient-Fortified Milk on Zinc Intake and Plasma Concentration in Adolescent Girls

Objective: To assess the effect of dietary fortified milk with zinc and other micronutrients on zinc intake and plasma zinc content of adolescent girls.

Methods: The study included 108 schoolgirls (12–18 years old) from northwest Mexico, randomly assigned to either the control group (CG; n = 55) or the intervention group consuming a regular diet plus fortified milk (MG; n = 53). At the beginning of the study, age, weight, and height were measured. Food intake by the 24-hour recall method and plasma zinc levels assessed by absorption spectrophotometry were determined before and after 27 days of fortified milk intake.

Results: At baseline, no significant group-related differences were observed for energy, protein intake, zinc intake, and plasma zinc level (p > 0.05), and 35.2% of participant girls did not achieve their zinc requirement. After 27 days of treatment, there were no significant differences in energy and protein intake between groups (p > 0.05). Zinc intake was higher for MG than CG (16.7 ± 8.3 mg/d vs 10.5 ± 6.4 mg/d; p < 0.01), and there was a lower proportion of low zinc intake in MG than for CG (7 vs 16, respectively; p = 0.04). In addition, plasma zinc improved in the MG (116.6 ± 26.9 μg/dL, p < 0.01) compared with CG (98.5 ± 26.6 μg/dL), and it was mainly attributed to the fortified milk intake, as the main dietary zinc contributor.

Conclusion: Fortified milk intake is effective in increasing both intake and plasma zinc levels of adolescent Mexican girls; therefore, it could be an adequate strategy for zinc deficiency prevention or correction among adolescent girls.