the nutritional status of - Health Systems Trust

3.3.18 NIACIN INTAKES
Niacin (vitamin B3) deficiency may develop in individuals who follow a maize based diet or with an impaired
absorption of the amino acid, tryptophan, which is a precursor for niacin. Tables 63 (a) and (b) indicate that mean
intakes of niacin of all groups were adequate. Intakes varied between 70 and 140 % of the RDA. However,
Dannhauser et al. (1996) (Table 63(c)) reported low intakes in rural black children from the Free State. Some groups
took in less than 67 % of the RDA. These results illustrate that, although mean intakes of groups stratified for age
and gender may be adequate, intakes of a specific group may be deficient. Therefore, although there may not be
a national deficiency problem with a specific nutrient, there may be a regional one, as seems to be the case for
niacin.
3.3.19 VITAMIN B6 INTAKES
Tables 64 (a), (b) and (c) give mean vitamin B6 (pyridoxine) intakes. In Table 65 the mean intakes are expressed as
a percentage of the RDA. Fourteen of the 27 groups, mainly black, coloured and Indian, had intakes less than 67 %
of the RDA. Vitamin B6 intake reflects the variety in the diet since this vitamin is found in several foods from both
animal and plant origin. Clearly, many South Africans lack variety in their diet.
3.3.20 FOLATE INTAKES
Tables 66 (a), (b) and (c) show the mean folate intakes of the different age and gender groups while Table 67
compares intakes of females in µg with different recommendations. From these tables it seems that Indian and
rural black women of child bearing age have low mean folate intakes. Unfortunately, no data for pregnant and
lactating women could be found. In addition to its protective effect against macrocytic anaemia, folate also protects
the foetus against neural tube defects. The low intakes of rural black and Indian women are, therefore, of concern
and should be addressed in nutrition programmes.
3.3.21 VITAMIN B12 INTAKES
From Tables 68 (a), (b) and (c) it is clear that vitamin B12 intakes were more than adequate in all groups measured.
The main reason is probably the adequate to high intakes of foods from animal origin. However, in a remote rural
area in Venda, subjects who followed a plant food-based diet, had normal to high blood levels of vitamin B12
(Vorster et al., 1994). This suggests that microbial production of B12, either in fermented foods and beverages, or in
the human colon, contributes to vitamin B12 “intakes”. It therefore seems that, at present, on a population level,
vitamin B12 status is sufficient. However, it is possible that individuals or specific groups, such as vegetarians or
the poorest of the poor, could have low intakes and low B12 status because of insufficient intakes of animal foods.
3.3.22 VITAMIN C INTAKES
Table 69 (a) shows that vitamin C or ascorbic acid intakes, when measured by the 24-hour recall method, were
inadequate in most of the black and Indian groups and in coloured girls aged 11 to 15.9 years. Data obtained by
other methods, showed adequate intakes (Table 69 (b)), except for rural black children aged 2 to 5.9 years who took
in 69 % of their RDA. The study of Dannhauser et al., (1996) on rural black infants and children under 6 years of
age in the Free State (Table 69 (c)) confirmed these low intakes. Vitamin C is the water soluble antioxidant provided
by fresh fruits and vegetables. The RDA’s are based on its anti-scurvy properties and early turnover studies (Food
and Nutrition Board, 1989). Taking the antioxidant properties into account, the RDA for smokers has been increased
from 60 to 100 mg per day. It is not known at what level of intake vitamin C will protect against chronic diseases
of lifestyle such as cancer, but it will probably be at higher levels than the existing RDA’s. Therefore, the low intake
of many South Africans is a matter of concern. These results emphasise the importance of increasing fruit and
vegetable intake of all South Africans.
3.3.23 VITAMIN A INTAKES
Tables 70 (a), (b) and (c) summarise vitamin A intakes of the different groups. Intakes measured by the 24-hour
recall method were low in 9 of the 20 groups, ranging from 37 to 86 % of the RDA’s. Data obtained by other
methods showed adequate intakes in most groups with black children being the exception.
Measurements and evaluation of vitamin A (retinol) intakes, are important. In addition to its essential functions in
normal growth and eyesight, vitamin A status is necessary for children to survive the consequences of respiratory
and gastrointestinal infections (reviewed by McLaren et al., 1993). There is no doubt that a high prevalence of
vitamin A deficiency among children in developing countries is a serious public health problem (Grant, 1994;
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