the nutritional status of - Health Systems Trust

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iron deficiency is a problem in these children. The biochemical variables of urban black primary school children are shown in Table 37. Four studies from four different provinces reported on a total of 1 975 children. Again, although mean values for the different groups were within normal reference ranges, high prevalences of low haemoglobin, serum ferritin and red blood cell folate were observed in some groups. The rural black children (Table 38) is the group most extensively studied. Data from 11 studies, covering seven of the nine provinces (KwaZulu-Natal and Free State being the exceptions) obtained from 2 326 children are summarised in Table 38. The general pattern in this group was high prevalences of low haemoglobin, ferritin, iron, vitamin A, ß- carotene, red blood cell folate, vitamin E, retinol binding protein and vitamin B6, indicating multiple micronutrient deficiencies. Interestingly, vitamin B12 concentrations were within normal ranges in all subjects where measured. In addition to the above mentioned micronutrients, calcium and vitamin D status of rural black children have been studied in some detail. Pettifor et al. (1979) compared 761 rural and urban black primary school children and found that 13.2 % of the rural children were hypocalcaemic compared with none of the urban children. Of the rural children, 41.5 % had elevated alkaline phosphatase concentrations. The authors estimated that the rural children took in only 125 mg calcium per day, compared to the 337 mg of the urban group. Van Rensburg et al. (1983) also reported a high prevalence of hypocalcaemia (35 %) in rural black subjects from the Transkei. However, in their sample, serum alkaline phosphatase concentrations were normal. Although rickets is rarely diagnosed in South Africa, the low serum calcium values are indicative of suboptimal micronutrient status in rural black children. 3.2.4 ADOLESCENTS Very little information and no recent studies on the biochemical profiles of whites, coloureds and Indians are available (Table 39). Mean concentrations of iron status variables of the Indian children were low, which is an indication of possible iron deficiency in this group. The mean values of the variables measured in urban black adolescents (Table 40) were all in the normal ranges. One study reported high prevalences (14.8 to 31.4 %) of low red blood cell folate. The rural black adolescents (Table 41) showed high prevalences of low serum phosphorus (25 %), red blood cell folate (4.2-19.3 %) haemoglobin (5-30 %), ferritin (14-20 %), and iron (26-27 %) in some groups. Clearly, the iron and folate micronutrient deficiencies seen in younger children are still present in adolescents. 3.2.5 ADULTS The data from 20 different studies, on 5 421 adult subjects from six provinces are summarised in Tables 42 and 43. Many other studies reported on lipid and lipoprotein profiles, as well as other risk factors of chronic diseases of lifestyle of adults. These were not included since many factors other than nutrition influence them. Unfortunately, no data on the nutritional status of Indian adults and very little on the other ethnic groups, especially the coloured group, could be found. Mean values of most variables fell within normal ranges. However, a small group of 20 year old white women had a 23 % prevalence of low iron status. Mean concentrations of iron status variables in both men and women of the coloured and black groups were low-normal or below normal, indicating that iron deficiency anaemia is present in many adult South Africans. The group of 100 elderly white men and women included in Table 42 is not representative of all elderly whites. They were included in the study of Kruger (1990) because they were healthy. Nevertheless, the data show that healthy elderly people have biochemical variables which are in the normal ranges for younger adults. Although vitamin B12 values were normal to high in all groups measured, one study (Johnson & Van der Westhuizen, 1989) found that 21 % of the women and 33 % of the men in a sample of 100 elderly rural blacks had low circulating vitamin B12 concentrations. 3.2.6 COMMENTS The limited number of studies which reported on the biochemical variables of nutritional status focused mainly on iron, vitamin A and folate status. A few studies gave information on other vitamins and some minerals. The biochemical data revealed high prevalences of vitamin A, iron and folate deficiencies in pre- and primary school children. These micronutrient deficiencies were also seen in adolescents and iron deficiencies were found in adult men and women. There were indications that the status of other micronutrients (vitamin B6, E and also calcium) may be low in many groups. Clearly, more information on specific micronutrients on a national level is needed, but at this stage, it seems that vitamin A, iron and folate deficiencies in many South Africans need immediate attention. 12
3.3 NUTRIENT INTAKES 3.3.1 INTRODUCTION Measurements of what people eat and analyses of their diets to obtain nutrient intakes, can give valuable information on nutritional status. Nutrient intake data can be used to evaluate the adequacy of diets, to establish nutrient goals, for food and nutrition policy decisions and to study the relationship between nutrient intakes and health and disease. There has never been a national survey of food and nutrient intakes of South Africans. However, several authors have published intake data obtained in studies throughout the country. Much of this data published between 1979 and 1994 has been combined in a meta-analysis by the South African Nutrition Survey Study group (SANSS group). The SANSS (1995) analysis consists of two sets of tables, compiled from 55 studies which met inclusion criteria regarding randomisation, numbers of subgroups, data base used for nutrient analysis and specific age and ethnic groupings. The first set (a) represents studies in which the 24-hour recall method was used and the second set (b) represents data obtained from using other dietary assessment techniques, such as food frequency questionnaires, diet histories or weighed records. In the present analysis, a third set of tables (c) are included. These were compiled from nine separate studies representing data published in 1995 and 1996, as well as a few studies that were not included in the meta-analysis, mainly because age groupings differed and no distinctions were made between the sexes. The tables are numbered and presented according to nutrients. Intakes are stratified for gender (sex), age and ethnic group and are compared with the USA recommended dietary allowances (RDA’s) of the Food and Nutrition Board (1989), as well as with the South African dietary guidelines (Health Matters Advisory Committee, 1992), where appropriate. In a few instances, WHO, British and European recommendations (Garrow & James, 1993) were also used for comparison. 3.3.2 ENERGY INTAKES Tables 44 (a), (b) and (c) give the mean energy intake of the different age and ethnic groups. Energy intakes of infants 0 to 2 years old were adequate in all population groups, but fell in 2-6 years old rural black children to between 83 and 60 % of the RDA’s. The intakes of the other groups, except for rural black children, all seem adequate. The 24-hour recall method measured low intakes in adult women, except for one group of 95 rural African women from KwaZulu-Natal which reported a mean intake of 10 148 kJ which was high compared with the RDA of 9 240 kJ. These low intakes were not supported by studies which used other assessment techniques nor by the 24-hour recall studies included in Table 44(c). The 24-hour recall method tends to give lower intake data than other methods (Bingham, 1987). However, a survey of nutrient intakes of adults in Britain in which weighed records were used, also found low mean energy intakes of 7 231 and 6 730 kJ for 35 to 49 and 60 to 64 year old women (Gregory et al., 1990). It is difficult to meet micronutrient intakes on such low energy diets. Therefore, if intakes are kept low to maintain ideal body weight, advice should be aimed at increasing activity and energy expenditure. In general, except for rural black children aged 2 to 6 years, mean energy intakes of South African groups of children, adolescents and adults from all ethnic groups seem to be adequate. 3.3.3 PROTEIN INTAKES Tables 45 (a), (b) and (c) indicate that intakes of total protein in all groups either met or exceeded recommended intakes. Figures 1 to 4 show, however, that especially in rural blacks, almost two-thirds of the protein came from plant sources. Therefore, unless legumes and grains are carefully balanced in meals, it is possible that not enough essential amino acids are taken in for protein synthesis and growth. Additionally, in low energy diets as seen in the rural black children, dietary proteins could be used as an energy source and not for protein synthesis. Steyn et al. (1992, 1993) showed that rural black children ate enough portions from the meat and cereal groups, but had inadequate intakes of milk, fruits and vegetables. Therefore, although total protein intakes exceeded the RDA’s, the quality of protein in the diets of rural black children can be improved by increased milk intakes. The diet history and food frequency methods tended to measure higher protein intakes than the 24-hour recall method. 3.3.4 FAT INTAKES Total fat intakes are given in Tables 46 (a), (b) and (c). The percentages of total energy provided by fat (calculated from the means in Tables 44 and 46 (a) and (b)) are given in Table 47. Table 47 (c) contains data from studies not included in the meta-analysis. The pattern that emerges from these tables is that rural blacks have a low-fat diet and urban blacks already follow a diet much higher in fat than the rural diet, but still more prudent than the diets 13
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Page 42 and 43: References Agenbag S, Matthée V. 1
Page 44 and 45: Coovadia HM. 1993. Overview of maln
Page 46 and 47: Ijsselmuiden CB. 1984. Nutritional
Page 48 and 49: May J, Carter M, Posel D. 1995. The
Page 50 and 51: Richter LM. 1993. Malnutrition and
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