the nutritional status of - Health Systems Trust

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
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