Background - Food and nutrition insecurity severely compromises the quality of life in farm communities in South
Africa. Although food‐based approaches are more sustainable strategies to address malnutrition,
most other strategies only target the alleviation of single micronutrients. Synergies between
nutrients demand a wider scope; food‐based strategies need to focus on improving both overall diet
quality and the well‐being of rural and urban populations. Agricultural biodiversity is crucial in such
strategies to improve food security and health. This thesis aims to investigate the effect of African
leafy vegetables (ALVs) on the alleviation of micronutrient deficiencies in school children residing in
the North West Province of South Africa.
Methods - Four focus group discussions assessed primary caregivers’ (n=29) knowledge, perceptions and use of
indigenous and traditional plants. Thereafter, the research focused on the leaves of Amaranthus
cruentus (amaranth), Cleome gynandra (spiderplant), Cucurbita maxima (pumpkin) and Vigna
unguiculata (cowpea). Sensory acceptability to children of selected ALV dishes, prepared in a
traditional way (n=98) and prepared with gravy, was assessed (n=80). The nutrient composition and
the bio‐accessibility of iron and zinc in these ALVs were determined. A randomised controlled trial to
investigate the effect of consumption of these ALVs on the iron, vitamin A en zinc status of primary
school children (grade R – grade 4) followed. Children of two rural farm schools were randomly
allocated per grade and school to receive either daily (five days/week) 300 gram cooked ALVs with
the school meal starch (N=86) or the normal school meal (N=81) for three months. Results - Caregivers were positive about using ALVs, transferring knowledge from generation to generation.
Children found dishes made with ALVs, prepared in the traditional way as well as with gravy,
acceptable in terms of colour, smell and taste. ALVs contributed 11.6 ‐ 15.8 mg iron and 1.4 ‐ 3.7 mg
zinc per meal. Amaranth‐and‐spiderplant has the highest amount of bio‐accessible iron (0.42 mg
iron). All dishes contain 0.3 mg bio‐accessible zinc. At baseline, intervention and control children
were deficient for Hb <11.5 g/dL (16.0% and 10.5%), serum ferritin <15 μg/L (16.3% and 18.5%),
serum retinol <20 μg/dL (7.0% and 2.5%) and serum zinc <65 μg/dL (75.6% and 75.3%). No
significant estimated intervention effect was found.
Conclusion - Caregivers possessed knowledge of ALVs and were positive about their use. Based on dialyzable iron
and zinc, the contribution of the ALV dishes towards dietary requirements is more substantial for
iron than zinc. The randomised controlled trial showed that ALVs unable to improve serum retinol,
serum ferritin or hemoglobin in mildly deficient children or those with low status zinc. Furthermore,
despite the low zinc status in our population, ALV consumption did not improve serum zinc
concentrations. Based on the more theoretical and indirect study results, including both caregivers’
and children’ positive image of ALVs, and the nutrient composition and iron and zinc bio‐accessibility
of the ALVs, these selected vegetables do have the potential to contribute to the micronutrient
intake of school children. However, the importance of ALVs might not necessary be to serve as a
strategy for micronutrient deficiency alleviation, but rather in the diversification of the diet in
resource‐poor settings and thereby contribute to the micronutrient intake. / PhD (Nutrition), North-West University, Potchefstroom Campus, 2014
| Identifer | oai:union.ndltd.org:NWUBOLOKA1/oai:dspace.nwu.ac.za:10394/12204 |
| Date | January 2014 |
| Creators | Van der Hoeven, Marinka |
| Source Sets | North-West University |
| Language | English |
| Detected Language | English |
| Type | Thesis |
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