Effect of an improved complementary food on nutrition of Zambian infants
Background: Infant growth faltering is common in developing countries. A major cause is inappropriate feeding practices and poor quality complementary foods with low energy density and deficiency in micronutrients and which may displace breast milk. The impact of micronutrient fortification of complementary foods or adding a-amylase to increase energy density on growth of infants from middle income urban populations in developing countries has been inadequately studied. Objectives: To assess current complementary feeding practices, develop and test the acceptability and effect of amylase-treated-fortified complementary blends named Chilenje Baby Mix (CBM) on growth and haemoglobin concentration of infants from a middle income community in Lusaka, Zambia. Design: Three-stage study comprising assessment of, 1) current complementary feeding practices, 2) acceptability of amylase-treated-fortified complementary food and, 3) the effect of the complementary food on growth, haemoglobin concentration and breast milk intake of 9-month old infants in a randomized controlled trial. Methods: Current complementary feeding practices were assessed by qualitative (focus group discussions, interviews and home observations) and quantitative methods. Acceptability to mothers of roasted maize-beans-groundnuts- bambaranuts porridge recipes was assessed prior to the industrial production of a- amylase-treated-fortified blends. Infants were randomized to receive a fortified blend with (CBMA) or without amylase (CBM) from 6-9 months of age. Anthropometric measurements, dietary intake and morbidity were determined monthly. Non-intervention infants were measured at 9 months of age. Breast milk intake was determined by deuterium oxide dilution method in a non-random subset of infants at 9 months. Results: Mothers had wide knowledge on optimal infant feeding, but actual practices were constrained by food cost and time availability, a-amylase enhanced porridge acceptability and caused 1000-fold reduction in porridge viscosity. The developed blend cost half as much as the average price of commercially complementary foods in the market. Mean weight gain between 6 and 9 months was 1.0 (SD 0.6) kg, 0.9 (SD 0.6) kg and 0.9 (SD 0.5) kg for infants in the CBM, CBMA and control groups, respectively (p = 0.54). Mean length at 9 months was 71.8 (SD 2.5) cm, 71.3 (SD 1.5) cm and 70.9 (SD 2.4) cm for infants in the CBM, CBMA and control groups, respectively (p = 0.06) infants in CBM had significantly greater length (p = 0.04) than infants in the control group by least square differences. Infants in both CBM and CBMA had significantly greater biceps (p = 0.02), subscapular (p < 0.001) and suprailiac skinfolds (< 0.001) and percent fat mass (p = 0.01) than infants in the control group. Infants in both CBM and CBMA had significantly greater haemoglobin concentration (p = 0.03) than infants in the control group 104 (SD 12) g/L, 103 (SD 12) g/L and 98 (SD 14) g/L for CBM, CBMA and control groups, respectively . The mean breast milk intake was 614 (SD 271) g/day, 635 (SD 193) g/day and 653 (SD 221) g/day (p = 0.87) and the mean energy intakes from breast milk and complementary foods represented 116%, 112% and 115% of the RDA for infants in CBM, CBMA and control groups, respectively. Infants in both CBM and CBMA had significantly greater intakes of calcium (p = 0.01), iron (p < 0.001), zinc (p < 0.001), vitamin A (p = 0.01), vitamin C (p < 0.001), thiamine (p = 0.03) and riboflavin (p = 0.02) than infants in the control group. Conclusion A cheap and acceptable industrially processed fortified complementary blend was developed. The porridge blend resulted in moderate improvement in infant length, but had more obvious improvement in haemoglobin concentration without adverse effect on breast milk intake. This blend may be used to improve micronutrient status and health of infants in middle income urban communities in developing countries.