Manufactured complementary foods for infant and young child feeding in Asia: micronutrient adequacy and improvement
Introduction: The complementary diets of infants and young children in Asia often contain inadequate levels of the problem micronutrients - iron, zinc, and calcium, and sometimes, high levels of phytate which inhibit the absorption of these micronutrients. As a result, the World Health Organization (WHO) recommends the consumption of fortified complementary foods. However, to date, no studies have assessed the nutrient adequacy or quality of manufactured complementary foods currently sold in Asia. The aims of this study were to assess the adequacy of the iron, zinc, and calcium content of some manufactured complementary foods currently sold in Asia, and to establish appropriate levels of fortification for these micronutrients in selected cereal-based manufactured complementary foods sold in three Asian countries – the Philippines, Mongolia, and Cambodia. Methods: A market sample of 33 commercially available, cereal-based manufactured complementary foods, were collected from Indonesia, the Philippines, Thailand, China, and Mongolia. The iron, zinc, and calcium content of the manufactured complementary foods were analysed using atomic absorption spectrophotometry, and the phytate content (based on hexa- and penta-inositol phosphate) was measured using high-performance liquid chromatography. The micronutrient adequacy of the manufactured complementary foods were assessed through comparison with the WHO estimated needs for iron, zinc, and calcium, assuming that breast-fed infants aged 9-11 mos consume 50 g per day (dry weight). The potential bioavailability of iron, zinc, and calcium in the complementary foods was estimated by a comparison with the recommended phytate-to-mineral molar ratios. Appropriate fortification levels of cereal-based manufactured complementary foods using WHO guidelines were determined for infants and toddlers aged 9 to 36 months from the Philippines, and toddlers aged 12 to 36 months from Mongolia, and Cambodia. Observed nutrient intake distributions for children from each respective country were transformed to usual intakes using the programme PC-SIDE, adjusting for within-subject variation based on intake data from two days during the 2003 National Nutrition Survey of the Philippines. Appropriate levels of fortification were determined using two methods recommended by WHO: the IOM conventional approach (EAR cut-point method for zinc and calcium, and full probability approach for iron), and the WHO alternative approach. Results: Although 85% of the manufactured complementary foods analysed were fortified, none met the estimated needs for breastfed infants aged 9-11 months for all three problem micronutrients. However, nine met the estimated needs for calcium alone. Furthermore, 76% of the manufactured complementary foods had a phytate-to-iron molar ratio above the level said to be indicative of satisfactory iron bioavailability. Derivation of fortification levels using the IOM conventional approach yielded much higher levels of fortification than those estimated using the WHO alternative approach (i.e. 6.5 – 9.8 mg vs 0 – 4 mg of iron per day, and 318 – 389 mg vs 5 – 256 mg of calcium per day). However, the IOM conventional approach plans for a low prevalence (i.e. 2-3%) of inadequate intakes of micronutrients, whereas the WHO alternative approach plans fortification levels at the estimated average requirement (i.e. 50% of the population have inadequate intakes). No additional zinc as a fortificant appear to be required in the three populations studied, as determined by both the IOM conventional and the WHO alternative approach. Conclusion: These results highlight the urgent need to fortify manufactured complementary foods at appropriate levels of absorbable micronutrients. Simpler, informed guidelines for the fortification of cereal-based complementary foods are required to inform policy and regulation at the government level, and to help manufacturers produce manufactured complementary foods that are adequately fortified with bioavailable micronutrients.
Advisor: Gibson, Rosalind
Degree Name: Master of Science
Degree Discipline: Human Nutrition
Publisher: University of Otago
Keywords: Complementary food; Asia; infant; nutrient adequacy
Research Type: Thesis