Research Articles (Centre for Nutrition)
Permanent URI for this collectionhttp://hdl.handle.net/2263/5855
Browse
Recent Submissions
Now showing 1 - 6 of 6
Item Effects of reducing phytate content in sorghum through genetic modification and fermentation on in vitro iron availability in whole grain porridges(Elsevier, 2012-03) Kruger, Johanita; Taylor, J.R.N. (John Reginald Nuttall); Oelofse, Andre; andre.oelofse@up.ac.zaImproved iron availability from sorghum porridges will benefit many malnourished communities in rural Africa, where there is a high prevalence of iron deficiency. This research compared the efficacy of reducing sorghum phytate content by genetic modification (GM) and natural lactic acid fermentation on in vitro iron availability in porridges. GM low phytate, non-tannin (38% phytate reduction) and tannin (36% phytate reduction) sorghums and their null controls were processed into thick unfermented and fermented porridges. The inhibitory effect of the tannins seemed to prevent any increase in in vitro iron availability, regardless of the level of phytate reduction. Only the additive effect of GM in combination with fermentation in reducing the phytate content appeared to cause a substantial increase in in vitro iron availability in the GM fermented porridge (30%) made from the non-tannin line, compared to the GM unfermented porridge (8.9%) or the fermented porridge (17.6%) of the control sorghum. This could be of nutritional significance.Item Selenium concentration of maize grain in South Africa and possible factors influencing the concentration(South African Society for Animal Science, 2012) Courtman, C.; Van Ryssen, J.B.J.; Oelofse, Andre; jvryssen@up.ac.zaA total of 896 maize grain samples were obtained from all the maize silos throughout South Africa (231 silos) and analysed for selenium (Se) content. This information was used to compile a regional distribution map of the Se content of maize grain in South Africa. Of the samples analysed, 94% contained below 50 μg selenium/kg DM and can thus be classified as deficient from an animal and human nutritional point of view. Maize grain in South Africa is therefore a poor source of Se for animals and humans. The geographical distribution of Se values of maize grain is consistent with that of previous studies on the Se status of herbivores in South Africa, suggesting that plants growing in most of the maize-producing areas of the country contain low concentrations of Se. However, these findings contradict those of the soil Se status in the country as reported by the Agricultural Research Council’s Institute for Soil, Water and Climate, which states that the eastern part of the maize-producing areas of the country tends to have adequate to high soil Se levels and the western areas to have low levels. These contradictory results can be explained to a large extent by the varying soil pH throughout the country. Soil pH plays a primary role in the availability of selenium to plants. Although the eastern parts of the country tend to have high Se concentration in the soil, it is not available to the maize plant owing to a low soil pH, while in the western parts of the country, where soil pH may be suitable for Se uptake by plants, there seems to be an inadequate concentration of available Se in the soil.Item The protein dispersibility index in the quality control of heat-treated full-fat soybeans : an inter-laboratory study(South African Society for Animal Science, 2011) Palic, D.; Modika, Kedibone Yvonne; Oelofse, Andre; Morey, Liesl; Coetzee, S.E.There are a number of laboratory methods that could be used to estimate the adequacy of full-fat soybean (FFSB) heat treatment. The protein despersibility index (PDI) has been claimed to have the most constant response to the heating of FFSBs. In this study, the PDI method has been subjected to an inter-laboratory test, including the participation of eight laboratories. Seven FFSB samples were processed by dry extrusion at temperatures ranging from 110 to 164 °C and analysed on the PDI. Processed FFSB samples were also assessed in a growth trial of broilers. The analysis of the FFSBs by the PDI method generated adequately-processed FFSB values of between 8.49% and 10.3%. Values above 10.3% described under-processed and below 8.49% over-processed FFSBs. The PDI method generated a good repeatability limit of 2.1%, but the reproducibility limit (7.73%) was too wide when taking into account the narrow range (8.5 – 10.3%) for adequately heat-treated FFSBs. Despite its simplicity and initial indications that it might be the best indicator of FFSB heat treatment, the PDI method did not prove that in this inter-laboratory study.Item African leafy vegetables consumed by households in the Limpopo and KwaZulu-Natal provinces in South Africa(Health and Medical Publishing Group, 2010-02) Faber, Mieke; Oelofse, Andre; Van Jaarsveld, P.J.; Wenhold, Friedeburg Anna Maria; Jansen van Rensburg, W.S.OBJECTIVES: The objectives of this study were to determine the availability of, access to and nutrition-related uses of African leafy vegetables in rural and urban households; and to determine the β-carotene content of the dominant African leafy vegetable. DESIGN: The study consisted of a qualitative explorative phase (field walks, semi-structured interviews with key informants, focus group discussions) at two rural sites; and a quantitative household survey (questionnaire) at two rural and one urban site. Amaranth leaves were analysed for β-carotene content. SETTINGS AND SUBJECTS: The household survey included households at a rural site in Limpopo province (n = 100); and a rural (n = 101) and urban (n = 391) site in KwaZulu-Natal province, South Africa. RESULTS: A variety of edible plants were identified during field walks at the two rural sites. Focus group discussions narrowed this down to ten plants at the rural Limpopo site and six at the rural KwaZulu-Natal site. The most popular leaves were amaranth (Amaranthus spp), spider plant (Cleome gynandra), wild watermelon (Citrullus lanatus) and blackjack (Bidens spinosa), consumed individually or mixed with other leaves. Rural households procured leaves mostly from the wild whereas urban households relied more on informal markets. In Limpopo, leaves were dried and stored for consumption during winter. KwaZulu-Natal households considered African leafy vegetables food for the poor. Leaves were boiled in salted water, or steamed and then fried in oil. Fried and boiled amaranth leaves contained 627 and 429 μg retinol activity equivalents/100 g respectively. CONCLUSIONS: Availability of, access to and nutrition-related uses of African leafy vegetables are context-specific, with inter- and intraprovincial rural/urban differences. Information collected during small studies within a specific area can therefore not be generalised for the overall South-African population. Amaranth can potentially contribute significantly to vitamin A requirements of nutritionally vulnerable communities.Item Primary health care facility infrastructure and services and the nutritional status of children 0 to 71 months old and their caregivers attending these facilities in four rural districts in the Eastern Cape and KwaZulu-Natal provinces, South Africa(Health and Medical Publishing Group, 2010-03) Schoeman, Serina; Smuts, C.M.; Faber, Mieke; Van Stuijvenberg, M.; Oelofse, Andre; Laubscher, J.A.; Benade, A.J.S.; Dhansay, M.A.OBJECTIVE: To assess primary health care (PHC) facility infrastructure and services, and the nutritional status of 0 to 71-month-old children and their caregivers attending PHC facilities in the Eastern Cape (EC) and KwaZulu-Natal (KZN) provinces in South Africa. DESIGN: Cross-sectional survey. SETTING: Rural districts in the EC (OR Tambo and Alfred Nzo) and KZN (Umkhanyakude and Zululand). SUBJECTS: PHC facilities and nurses (EC: n = 20; KZN: n = 20), and 0 to 71-month-old children and their caregivers (EC: n = 994; KZN: n = 992). METHODS: Structured interviewer-administered questionnaires and anthropometric survey. RESULTS: Of the 40 PHC facilities, 14 had been built or renovated after 1994. The PHC facilities had access to the following: safe drinking water (EC: 20%; KZN: 25%); electricity (EC: 45%; KZN: 85%); flush toilets (EC: 40%; KZN: 75%); and operational telephones (EC: 20%; KZN: 5%). According to more than 80% of the nurses, problems with basic resources and existing cultural practices influenced the quality of services. Home births were common (EC: 41%; KZN: 25%). Social grants were reported as a main source of income (EC: 33%; KZN: 28%). Few households reported that they had enough food at all times (EC: 15%; KZN: 7%). The reported prevalence of diarrhoea was high (EC: 34%; KZN: 38%). Undernutrition in 0 to younger than 6 month-olds was low; thereafter, however, stunting in children aged 6 to 59 months (EC: 22%; KZN: 24%) and 60 to 71 months (EC: 26%; KZN: 31%) was medium to high. Overweight and obese adults (EC: 49%; KZN: 42%) coexisted. CONCLUSION: Problems regarding infrastructure, basic resources and services adversely affected PHC service delivery and the well-being of rural people, and therefore need urgent attention.Item Linking smallholder agriculture and water to household food security and nutrition(Water Research Council, 2007-06) Wenhold, Friedeburg Anna Maria; Faber, Mieke; Van Averbeke, W.; Oelofse, Andre; Van Jaarsveld, P.; Jansen van Rensburg, W.S.; Van Heerden, I.; Slabbert, R.; friede.wenhold@up.ac.zaPromoting household food security and reducing malnutrition rates of a growing population with the same amount of water is a challenge facing South African nutritionists and agriculturalists alike. Apart from non-food related effects of agriculture in general, the crop and livestock production practices of the South African smallholder farmer may have nutritional implications, primarily when practised on residential land and resulting in home consumption. Yet, few studies have systematically investigated the impact thereof. It appears that crop diversification, gender issues and nutrition education are among the important factors that strengthen the link between agriculture and nutrition. Since food production is the most water-intensive activity in society, nutritional water productivity (i.e. nutrition per volume water) of foods and the nutritional water footprint of diets should be investigated in order to achieve a sustainable solution. This implies that both the demand for a diet consisting predominantly of water-productive plant products, as well as the supply thereof, be addressed.