Use of a "Super-child'' Approach to Assess the Vitamin A Equivalence of Moringa oleifera Leaves, Develop a Compartmental Model for Vitamin A Kinetics, and Estimate Vitamin A Total Body Stores in Young Mexican Children

Background: Worldwide, an estimated 250 million children < 5 y old are vitamin A (VA) deficient. In Mexico, despite ongoing efforts to reduce VA deficiency, it remains an important public health problem; thus, food-based interventions that increase the availability and consumption of provitamin A-rich foods should be considered. Objective: The objectives were to assess the VA equivalence of H-2-labeled Moringa oleifera (MO) leaves and to estimate both total body stores (TBS) of VA and plasma retinol kinetics in young Mexican children. Methods: beta-Carotene was intrinsically labeled by growing MO plants in a (H2O)-H-2 nutrient solution. Fifteen well-nourished children (17-35 mo old) consumed pureed MO leaves (1 mg beta-carotene) and a reference dose of [C-13(10)] retinyl acetate (1 mg) in oil. Blood (2 samples/child) was collected 10 times (2 or 3 children each time) over 35 d. The bioefficacy of MO leaves was calculated from areas under the composite "super-child'' plasma isotope response curves, and MO VA equivalence was estimated through the use of these values; a compartmental model was developed to predict VA TBS and retinol kinetics through the use of composite plasma [C-13(10)] retinol data. TBS were also estimated with isotope dilution. Results: The relative bioefficacy of beta-carotene retinol activity equivalents from MO was 28%; VA equivalence was 3.3: 1 by weight (0.56 mu mol retinol: 1 mu mol beta-carotene). Kinetics of plasma retinol indicate more rapid plasma appearance and turnover and more extensive recycling in these children than are observed in adults. Model-predicted mean TBS (823 mu mol) was similar to values predicted using a retinol isotope dilution equation applied to data from 3 to 6 d after dosing (mean +/- SD: 832 +/- 176 mmol; n = 7). Conclusions: The super-child approach can be used to estimate population carotenoid bioefficacy and VA equivalence, VA status, and parameters of retinol metabolism from a composite data set. Our results provide initial estimates of retinol kinetics in well-nourished young children with adequate VA stores and demonstrate that MO leaves may be an important source of VA.