Alexander A Kalimbira

Dietary mineral supplies in Africa

Dietary micronutrient deficiencies (MNDs) are widespread, yet their prevalence can be difficult to assess. Here, we estimate MND risks due to inadequate intakes for seven minerals in Africa using food supply and composition data, and consider the potential of food-based and agricultural interventions. Food Balance Sheets (FBSs) for 46 countries were integrated with food composition data to estimate per capita supply of calcium (Ca), copper (Cu), iron (Fe), iodine (I), magnesium (Mg), selenium (Se) and zinc (Zn), and also phytate. Deficiency risks were quantified using an estimated average requirement (EAR) ‘cut-point’ approach. Deficiency risks are highest for Ca (54% of the population), followed by Zn (40%), Se (28%) and I (19%, after accounting for iodized salt consumption). The risk of Cu (1%) and Mg (<1%) deficiency are low. Deficiency risks are generally lower in the north and west of Africa. Multiple MND risks are high in many countries. The population-weighted mean phytate supply is 2770 mg capita−1 day−1. Deficiency risks for Fe are lower than expected (5%). However, ‘cut-point’ approaches for Fe are sensitive to assumptions regarding requirements; e.g. estimates of Fe deficiency risks are 43% under very low bioavailability scenarios consistent with high-phytate, low-animal protein diets. Fertilization and breeding strategies could greatly reduce certain MNDs. For example, meeting harvestplus breeding targets for Zn would reduce dietary Zn deficiency risk by 90% based on supply data. Dietary diversification or direct fortification is likely to be needed to address Ca deficiency risks.

Soil-type influences human selenium status and underlies widespread selenium deficiency risks in Malawi

Selenium (Se) is an essential human micronutrient with critical roles in immune functioning and antioxidant defence. Estimates of dietary Se intakes and status are scarce for Africa although crop surveys indicate deficiency is probably widespread in Malawi. Here we show that Se deficiency is likely endemic in Malawi based on the Se status of adults consuming food from contrasting soil types. These data are consistent with food balance sheets and composition tables revealing that >80% of the Malawi population is at risk of dietary Se inadequacy. Risk of dietary Se inadequacy is >60% in seven other countries in Southern Africa, and 22% across Africa as a whole. Given that most Malawi soils cannot supply sufficient Se to crops for adequate human nutrition, the cost and benefits of interventions to alleviate Se deficiency should be determined; for example, Se-enriched nitrogen fertilisers could be adopted as in Finland.

A high prevalence of zinc- but not iron-deficiency among women in rural Malawi:a cross-sectional study

BACKGROUND Zinc deficiency is often associated with nutritional iron deficiency (ID), and may be exacerbated by low selenium status. AIM To investigate risk of iron and zinc deficiency in women with contrasting selenium status. METHODS In a cross-sectional study, 1-day diet composites and blood samples were collected from self-selected Malawian women aged 18-50 years from low- (Zombwe) (n=60) and high-plant-available soil selenium (Mikalango) (n=60) districts. Diets were analyzed for trace elements and blood for biomarkers. RESULTS Zinc deficiency (>90 %) was greater than ID anemia (6 %), or ID (5 %), attributed to diets low in zinc (median 5.7 mg/day) with high phytate:zinc molar ratios (20.0), but high in iron (21.0 mg/day) from soil contaminant iron. Zombwe compared to Mikalango women had lower (p<0.05) intakes of selenium (6.5 vs. 55.3 µg/day), zinc (4.8 vs. 6.4 mg/day), iron (16.6 vs. 29.6 mg/day), lower plasma selenium (0.72 vs. 1.60 µmol/L), and higher body iron (5.3 vs. 3.8 mg/kg), although plasma zinc was similar (8.60 vs. 8.87 µmol/L). Body iron and plasma zinc were positive determinants of hemoglobin. CONCLUSION Risk of zinc deficiency was higher than ID and was shown not to be associated with selenium status. Plasma zinc was almost as important as body iron as a hemoglobin determinant.

Inventory on the dietary assessment tools available and needed in africa: a prerequisite for setting up a common methodological research infrastructure for nutritional surveillance, research, and prevention of diet-related non-communicable diseases

abstract Objective: To carry out an inventory on the availability, challenges, and needs of dietary assessment (DA) methods in Africa as a pre-requisite to provide evidence, and set directions (strategies) for implementing common dietary methods and support web-research infrastructure across countries. Methods: The inventory was performed within the framework of the “Africas Study on Physical Activity and Dietary Assessment Methods” (AS-PADAM) project. It involves international institutional and African networks. An inventory questionnaire was developed and disseminated through the networks. Eighteen countries responded to the dietary inventory questionnaire. Results: Various DA tools were reported in Africa; 24-Hour Dietary Recall and Food Frequency Questionnaire were the most commonly used tools. Few tools were validated and tested for reliability. Face-to-face interview was the common method of administration. No computerized software or other new (web) technologies were reported. No tools were standardized across countries. Conclusions: The lack of comparable DA methods across represented countries is a major obstacle to implement comprehensive and joint nutrition-related programmes for surveillance, programme evaluation, research, and prevention. There is a need to develop new or adapt existing DA methods across countries by employing related research infrastructure that has been validated and standardized in other settings, with the view to standardizing methods for wider use.

Iodine source apportionment in the Malawian diet

The aim of this study was to characterise nutritional-I status in Malawi. Dietary-I intakes were assessed using new datasets of crop, fish, salt and water-I concentrations, while I status was assessed for 60 women living on each of calcareous and non-calcareous soils as defined by urinary iodine concentration (UIC). Iodine concentration in staple foods was low, with median concentrations of 0.01 mg kg−1 in maize grain, 0.008 mg kg−1 in roots and tubers, but 0.155 mg kg−1 in leafy vegetables. Freshwater fish is a good source of dietary-I with a median concentration of 0.51 mg kg−1. Mean Malawian dietary-Iodine intake from food, excluding salt, was just 7.8 μg d−1 compared to an adult requirement of 150 μg d−1. Despite low dietary-I intake from food, median UICs were 203 μg L−1 with only 12% defined as I deficient whilst 21% exhibited excessive I intake. Iodised salt is likely to be the main source of dietary I intake in Malawi; thus, I nutrition mainly depends on the usage and concentration of I in iodised salt. Drinking water could be a significant source of I in some areas, providing up to 108 μg d−1 based on consumption of 2 L d−1.

Weight gain, physical activity and dietary changes during the seven months of first-year university life in Malawi

Abstract Objective: The objective of the study was to assess weight gain, physical activity and dietary changes during the first year of university life in Malawi. Setting: The setting was Bunda College of Agriculture, University of Malawi. Subjects: The subjects were first-year students (n = 47) enrolled for the 2008/2009 academic year. Method: A prospective cohort study was carried out, with repeated measures (November 2008 and June 2009). It included residential and nonresidential students. Data were collected using self-administered structured questionnaires. Weight, height and mid-upper-arm circumference were measured. Results: There was a significant difference in mean weight gain between female (7.1 ± 3.2 kg, n = 26) and male students (9.6 ± 3.5 kg, n = 21) (p-value = 0.013). Overall, within the first year of university life, the students gained 8.5 ± 3.6 kg (p-value < 0.001), and a modest but significant height of 0.2 cm (p-value = 0.04). Body mass index (kg/m2) increased from 20.7 ± 3.2 to 23.9 ± 3.2 (p-value < 0.001). At the baseline, in general, the students lived sedentary lives, with 6.6 hours spent resting, 2.1 hours engaged in light activities, and 0.9 hours engaged in heavy activities. No significant changes were observed at the end of the study. Daily consumption of wheat products, meat and meat products, sugar, milk and milk products and margarine increased, while that of other foods such as fish, and fruits and vegetables declined. Conclusion: Unprecedented freshman weight gain was observed in this study. Transition to university life in Malawi might be the beginning of poor dietary and lifestyle changes. If not restrained, these could elevate the risk of lifestyle diseases in people who have attained tertiary education and who are important to national development.

The impact of an integrated community-based micronutrient and health programme on stunting in Malawian preschool children

OBJECTIVE To assess the impact of the 1996-2005 integrated community-based micronutrient and health (MICAH) programme on linear growth retardation (stunting) in Malawian preschool children living in rural areas. DESIGN Prospective study of three large-scale cross-sectional surveys conducted in 1996, 2000 and 2004 in MICAH and Comparison populations. SETTING Rural areas in Malawi. SUBJECTS Preschool children (6.0-59.9 months) from randomly selected households (474 from the 1996 baseline survey; 1264 from 2000 MICAH areas; 1500 from 2000 Comparison areas; 1959 from 2004 MICAH areas; and 1008 from 2004 Comparison areas), who responded to a household questionnaire, were weighed and measured using standard protocols. RESULTS At the baseline in 1996, the prevalence of stunting (60.2 %) was very high. By 2000, the prevalence of stunting had declined to 50.6 % and 56.0 % (chi2 = 7.8, P = 0.005) in MICAH and Comparison areas, respectively. In 2004, the prevalence of stunting did not differ significantly between MICAH and Comparison areas (43.0 % v. 45.1 %; chi2 = 1.11, P = 0.3). Severe stunting affected 34.7 % of children at baseline, which declined to 15.8 % and 17.1 % (chi2 = 0.86, P = 0.4) in MICAH and Comparison areas, respectively, by 2004. Regional variations existed, with proportionately fewer children from the Northern region being stunted compared to their Central and Southern region counterparts. CONCLUSION Given the length of implementation, wide-scale coverage and positive impact on child growth in Phase I (1996-2000), the MICAH programme is a potential model for combating linear growth retardation in rural areas in Malawi, although the catch-up improvement in Comparison areas during Phase II (2000-2004) cannot be adequately explained.

The impact of an integrated community-based micronutrient and health programme on anaemia in non-pregnant Malawian women

OBJECTIVE To assess the impact of an integrated community-based micronutrient and health (MICAH) programme on anaemia (Hb < 120 g/l) among non-pregnant rural Malawian women aged 15-49 years from communities that participated in the 1996-2005 MICAH programme. DESIGN Prospective study of two large-scale cross-sectional surveys conducted in 2000 and 2004 as part of programme evaluation in MICAH and Comparison areas. SETTING Rural areas across Malawi. The MICAH programme implemented a comprehensive package of interventions to reduce anaemia, based on a broad range on direct and indirect causes in Malawi. The project approaches included: Fe supplementation; dietary diversification and modification; food fortification; and strengthening primary health care. PARTICIPANTS Non-pregnant women of childbearing age (15-49 years old, n 5422), from randomly selected households that responded to a household questionnaire, had their Hb measured from finger-prick blood samples using the HemoCue. RESULTS In 2000, there was no significant difference in Hb concentration between MICAH and Comparison areas (mean (SE): 117.4 (0.4) v. 116.8 (0.5) g/l, P > 0.05) and the corresponding prevalence of anaemia (53.5 % v. 52.9 %, P > 0.05). By 2004, Hb concentration had increased significantly in MICAH but not in Comparison areas (mean (SE): 121.0 (0.4) v. 115.7 (0.6) g/l, P < 0.001), and the prevalence of anaemia had declined significantly in MICAH areas (53.5 % to 44.1 %, chi2 = 28.2, P < 0.0001) but not in Comparison areas (52.8 % to 54.0 %, chi2 = 0.3, P = 0.6). CONCLUSIONS The MICAH programme was an effective public health nutrition programme that was associated with significant reductions in the prevalence of anaemia among non-pregnant rural Malawian women.

The difficulty of assessing night blindness in Malawi: Language barriers

To the Editor: For a long time vitamin A deficiency (VAD) has been recognised as a public health problem in Malawi, primarily on the basis of localised studies. However, a national micronutrient survey conducted in 20012 showed that the prevalence of VAD (serum retinol < 20 mg/dl3) was 59.2% in preschool children and 57.4% in non-pregnant women of reproductive age, clearly indicating a very serious public health problem

Reduced Morbidity Motivated Adoption of Infant and Young Child Feeding Practices after Nutrition Education Intervention in Rural Malawi

ABSTRACT This study assessed caregivers’ knowledge and practices and factors that influence the adoption of improved infant and young child feeding (IYCF) practices after nutrition education in Kasungu and Mzimba districts among 198 caregivers. Mixed-methods convergent-parallel design, including knowledge tests, focus group discussions, and in-depth interviews in the intervention areas, was used to collect quantitative and qualitative data. Data were analyzed using count regression and content analysis, which showed that knowledge increased among caregivers after nutrition education. The knowledge about diet diversification for young children as well as about hygienic practices when preparing food and during feeding improved in addition. Enhanced health among children motivated caregivers to apply improved IYCF practices. The study was based on the caregivers’ reports. Long-term effects of exposure to nutrition education are unknown. However, the nutrition education that focused on the child’s health benefits motivated mothers to adopt improved IYCF practices.