Micronutrient supplementation of young stunted Beninese children: effects on appetite and growth performance

Linear growth retardation (stunting) still has a high prevalence rate in developing countries (ACC/SCN, 2000). In the republic of Benin reported prevalence rates range from 25% to 40%. In malnourished children it is quite common to observe a combination of multiple micronutrient deficiency, loss of appetite and growth retardation. However, possible interactions between these parameters are not yet adequately mapped.The research presented in this thesis was performed to examine whether micronutrient supplementation may improve appetite and growth in young stunted children. We have performed three micronutrient supplementation studies on stunted children in southern Benin and we have measured effects on appetite and growth performance. In order to be able to assess appetite, an appropriate measuring procedure for appetite had to be developed.For measuring appetite in humans there is no standard, but the habitual daily energy intake is usually considered to be the most appropriate proxy for appetite. However, the common methods to assess habitual daily energy intake are quite invasive and time consuming, and therefore perhaps not appropriate for a quick assessment of young children's appetite. To develop an appropriate appetite measurement tool which can be applied in young Beninese children, we have carried out four trials on a total of 109 children, 18-30 months of age (Chapter 3). Ad libitum intakes of test foods (a maize porridge or rice) served after an overnight fast according to standardized offering procedures were measured on three days. The reproducibility (as coefficient of variation) of the appetite test as calculated from the triplicate measurements was 40% for the maize porridge ('aklui') and 25% for rice ('riz-au-gras'). Habitual breakfast and daily food intake were measured during three consecutive days. Energy intake from the maize porridge was positively and significantly associated with the daily energy intake (n=38, r=0.41, p < 0.05) and with the energy intake from breakfast (r=0.52, p < 0.01). Correlations for the rice test food were less pronounced and non-significant. We conclude that the ad libitum energy intake from a culturally appropriate and well-accepted food as maize porridge can be considered a valid estimate of appetite, provided a standardized procedure is used. If the appetite test is applied in intervention studies it may be necessary to perform the test in duplicate or triplicate (like we did) to perform statistical tests with sufficient power.The first intervention study was carried out to assess the impact of iron supplementation alone or in combination with a deworming treatment on the growth performance of 3-5 year old children (Chapter 2). A total of 177 children were selected from low-income households in a rural area in southern Benin and were allocated to one of four treatments: iron (60 mg elemental iron/day) + albendazole (200 mg/day for 3 consecutive days, at start of study and after one month), iron + albendazole-placebo, albendazole + iron-placebo or placebos. The group of children can be considered as stunted (58% had height-for-age Z-score < -2) and anemic (76% had Hb < 110 g/L), but not as wasted (2% had weight-for-height Z-score < -2). After three months of intervention the blood hemoglobin level in the iron-treated children was significantly increased by 5 g/L (p=0.032) when compared with the levels of the placebo children. There were no significant effects of iron and deworming treatment on growth performance. As expected, Ascaris lumbricoides and hookworm infections decreased significantly in albendazole-treated subjects (p < 0.05). A food consumption survey, performed after the supplementation period was finished, revealed that the overall diet of the children should be considered as marginal. Therefore, we hypothesised that the absence of positive intervention effects on growth performance might be due to a multiple micronutrient deficiency.Therefore, we have studied the effect of a multivitamin-multimineral supplementation on appetite and growth (Chapter 4). A placebo-controlled study was performed in which 101 stunted children (height-for-age Z-score < -2), aged 17-32 months, received either a multivitamin-multimineral supplement (VITALIA-tablets, containing 11 vitamins and 8 minerals) or a placebo. The tablets were given daily to the children for 6 weeks. Knee-heel length, length, weight, arm circumference and appetite were assessed three times before and three times after supplementation. Growth was also assessed 4 months after the intervention. Appetite was assessed using the appetite test procedure as described in Chapter 3 and knee-heel length was assessed using knemometry. Each test day, morbidity data and the mother's report on the child's appetite throughout the preceding day were recorded. We hypothesised that a 6-week supplementation would improve appetite of the children by 25%. However, no significant effects on appetite and growth could be detected. We hypothesised that this lack of effect in the present study might be associated with the high burden of helminth infections and the high level of iron deficiency. Perhaps, the iron content of the multivitamin-multimineral supplement had not been sufficient to compensate the iron deficiency or beneficial effects can only be obtained when the worm load is under control.Therefore, the aim of the third intervention study was to assess whether a combination of a multivitamin-multimineral supplement and an iron supplement would improve appetite and growth of 18-30 months old stunted and anemic Beninese children, provided that their wormload would be under control (Chapter 5). Hundred and fifty stunted (height-for-age Z-score < -2) and anemic children (Hb < 110 g/L) were selected and randomly assigned to one of four treatments: multivitamin-multimineral + iron, multivitamin-multimineral + placebo, placebo + placebo, and placebo + iron. Supplements were provided daily for 6 weeks and intake of tablets was supervised. The multivitamin-multimineral supplements were VITALIA-tablets (11 vitamins + 10 minerals) and iron was given as ferrous fumarate tablets (66 mg iron/tablet). A week before supplementation and during the last week of supplementation, all children received a deworming treatment. Each child was treated with 600 mg of mebendazole (200 mg per day during 3 consecutive days). Appetite, knee-heel length, dietary intake and morbidity status were assessed before and after supplementation. Length, weight, arm circumference and hemoglobin were assessed before, just after supplementation and 4 months after the intervention. Appetite was assessed by the validated appetite test using 'riz-au-gras' as test food. Dietary intakes were assessed during 3 consecutive days by means of the observed weighed record method. As expected, the iron-supplemented groups did show a significant improvement of blood hemoglobin level, but supplementation with iron or the multivitamin-multimineral supplement did not improve appetite or growth performance, despite the deworming treatment. The lack of improvement is difficult to explain. One of the explanations might be that micronutrients are only effective if the diet contains enough protein and energy. The dietary data indeed suggest that the overall quality of the children's diet was not appropriate and that most of the children suffer from a chronic protein-energy malnutrition. An other explanation might be that the duration of supplementation (6 weeks) had been too short to observe a meaningful improvement of appetite and growth. We suggest that future studies on appetite and growth performance should use a combined energy-protein-micronutrient supplement and that the supplementation duration should be sufficiently long for correcting the energy-protein-micronutrient deficiency.