Forms of malnutrition that affect children in developing countries and children’s nutritional requirements

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Zinc requirements and deficiency

Zinc is a trace mineral involved in all major human biochemical pathways (Hotz & Brown, 2004). Similar to iron requirements, the need for zinc for the growing body increases when breastfeeding ceases. Breast milk provides enough zinc for the first six months of life (Krebs, 2000). The recommended nutrient intake (RNI) for dietary zinc (mg/day) required to meet the ormative storage requirements at different zinc bioavailability for children aged one to six years is 2.4-2.9 mg/day at high bioavailability, 4.1-4.8 mg/day at medium and 8.3-9.6 mg/day at low bioavailability (WHO/FAO, 2004).
High intakes of cereal and legume foods with high phytate contents inhibit the absorption of zinc (Brown, Wuehler & Peerson, 2001). Low zinc intake, however, is not common in diets containing sufficient animal foods. Zinc deficiency is a condition that exists when the levels of zinc intake fall below the body’s requirement (Deshpande, Joshi & Giri, 2013). Zinc deficiency in children impairs immunity and increases the incidence of infections, growth failure and impaired neurobehavioral development (Brown et al., 2001). Zinc deficiency is also associated with the risk of morbidity and mortality related to diarrhoea, pneumonia and malaria in children (Caulfield & Black, 2004).
Globally, zinc deficiency is estimated at 17.3% (Wessells & Brown, 2012). Regions with the highest risk are South Asia (29.6%), closely followed by sub-Saharan Africa (25.6%). The 1999 National Food Consumption Survey in South Africa revealed inadequate zinc intake in 52–69% of all children aged one to nine years that were included in the study sample (Labadarios et al., 2000). Zinc intake was even lower in the diet of children living in rural areas. A similar observation was made in rural KwaZulu-Natal, in two to five year old children (Faber, Jogessar & Benadé, 2001). A recent study revealed a high prevalence of zinc deficiencies in preschool children aged three to five years in Vhembe district, Limpopo province (42.6%), mainly affecting girls (Motadi et al., 2015).

Vitamin A requirements and deficiency (VAD)

Vitamin A is a fat soluble vitamin whose physiological functions include maintaining good vision, cell differentiation, gene regulation and immune system functions (Gallagher, 2008). The recommended vitamin A intakes for children aged two to three and four to five years are 400 and 450 μg RE/day respectively (Joint FAO/WHO Expert Consultation on human vitamin and mineral requirements, 2004). Dietary sources include preformed sources of vitamin A which are found in animal foods such as liver and pro-vitamin A carotenoids in coloured fruits, vegetables and red palm oil. Vitamin A deficiency is diagnosed when the concentration of serum retinol falls below 0.70 mmol/l (Rice, West Jr. & Black, 2004).
In 2004, it was reported that 40% of all children under the age of five years from developing countries had a vitamin A deficiency ( UNICEF, 2004). An earlier report found that more than 70% vitamin A deficient children were in the regions of South Asia and sub-Saharan Africa (Mason, Lotfi, Dalmiya, Sethuraman & Deitchle, 2001). In 2013, the prevalence of vitamin A deficiency in South Africa was estimated at 43.6%, which had improved from the prevalence reported in the year 2005 of 63.6% (Shisana et al., 2013).

Iodine requirements and deficiency

Iodine is an important part of the thyroid hormones thyroxine (T4) and triiodothyronine (T3) (Joint FAO/WHO Expert Consultation on Human Vitamin and Mineral Requirements, 2004). The recommended iodine intake for children aged zero to 59 months is 90 μg/day (WHO/UNICEF & ICCIDD, 1996). Dietary sources of iodine include fish, seafood, kelp, drinking water and vegetables grown in iodine sufficient soil and iodated table salt (Vitti, Ross & Mulder, 2014).
Iodine deficiency is diagnosed when serum iodine levels fall below recommended levels (WHO, 2001a) resulting in the failure of the thyroid gland to synthesize enough thyroid hormone. Severe iodine deficiency leads to development of goitre and cretinism (Delange, 1994; 1996) and is the leading cause of brain damage, psychomotor retardation, intellectual impairment and mental retardation in children (Eastman & Zimmermann, 2009).
In 2002, the Eastern Mediterranean region had the highest prevalence of iodine deficiency (74%), followed by Africa (50%) (Ramakrishnan, 2002). In 2006, two million people worldwide were estimated to have inadequate iodine nutrition, with the global prevalence of iodine deficiency estimated at 35% and 43% in Africa (Allen, de Benoist, Dary & Hurrell, 2006). In 2008, it was reported that an estimated 32% school-age children had insufficient iodine intake (de Benoist, McLean, Andersson & Rogers, 2008). Of the children estimated to be iodine deficient, 73 million were living in South-East Asia and 58 million were living in Africa.

1 Introduction
1.1 Structure of the thesis
2 Literature Review
2.1 Malnutrition
2.2 Causes of malnutrition
2.2.1 Immediate causes of malnutrition
2.2.2 Underlying causes of malnutrition
2.2.3 Basic causes of malnutrition
2.3 Forms of malnutrition that affect children in developing countries and children’s nutritional requirements
2.3.1 Iron requirements and deficienc
2.3.2 Zinc requirements and deficiency
2.3.3 Vitamin A requirements and deficiency (VAD)
2.3.4 Iodine requirements and deficiency
2.3.5 Protein and energy requirements and Protein Energy Malnutrition (PEM) in children
2.3.5.1 Classification of PEM
2.4 Feeding practices and food intakes of young children
2.5 Ready-to-use therapeutic foods (RUTF)
2.6 Commercial foods for young children
2.7 Nutrition intervention strategies to combat micronutrient deficiencies
2.7.1 Micronutrient fortification
2.7.2 Micronutrient supplementation
2.7.3 Food-based dietary modification and diversification strategies
2.8 Importance of indigenous foods in rural diets
2.8.1 Sorghum
2.8.2 Cowpea
2.9 Antinutrients in sorghum and cowpea
2.9.1 Protease inhibitors
2.9.2 Phytic acid
2.9.3 Polyphenols
2.9.4 Oligosaccharides
2.9.5 Lectins (Haemagglutinins)
2.10 Traditional processing methods
2.10.1 Soaking
2.10.2 Hydrothermal processing
2.10.2.1 Boiling
2.10.2.2 Microwave cooking
2.10.3 Fermentation (lactic acid bacteria fermentation)
2.10.4 Malting and sprouting
2.10.5 Dehulling
2.11 Modern processing technologies
2.11.1 Micronisation
2.11.2 Extrusion cooking
2.12 Conclusions
3 Hypotheses and objectives
3.1 Hypothese
3.2 Objectives
4 Research
4.1 Influence of micronisation (infrared treatment) on the protein and functional quality of a ready-to-eat sorghum-cowpea African porridge for young child-feeding
4.1.1 Introduction
4.1.3 Results and discussion
4.1.3.1 Protein and lysine contents
4.1.3.2 In vitro protein digestibility (IVPD) and Protein Digestibility Corrected Amino Acid Score (PDCAAS).
4.1.3.3 Antinutrients
4.1.3.4 Hydration properties of the flour
4.1.3.5 Estimated contributions of the composite porridge meals to the protein and lysine requirements of young children
4.1.4 Conclusions
4.2 Effects of processing and addition of a cowpea leaf relish on the iron and zinc nutritive value of a ready-to-eat sorghum-cowpea porridge meal aimed at young children
5 General discussion
6 Conclusions and recommendations
7 References

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Protein, iron and zinc content and bioaccessibility of a ready-to-eat sorghum and cowpea meal developed for 2- to 5-year old African children