Introduction to Human Nutrition

272 Introduction to Human Nutrition

Table 10.7 illustrates these general trends with data
from the 1995 Australian National Nutrition Survey.
Twelve per cent of men and 21% of women in this
survey were identifi ed as LERs. The median energy
intake in non-LERs was approximately 6% higher in
men and 10% higher in women than for all men and
women, and vitamin and mineral intake approxi-
mately 5–10% higher in non-LER men and 6–15%
higher in non-LER women. Differences of this order
of magnitude are important in the context of the
assessment of dietary adequacy.
Relatively few studies have reported on differences
in foods eaten, but there appears to be a general ten-
dency for LERs to report more foods such as meat,
fi sh, vegetables, salads, and fruit, and fewer cakes,
biscuits, sugar, confectionery, and fats.

10.8 Assessment of dietary adequacy

Methods for evaluating dietary adequacy are described
in Chapter 7. This section simply draws attention to
the limitations of these methods.
The fi rst limitation is that the evaluation of nutri-
ent intake can provide only an estimate of the risk of
nutrient inadequacy for a population or an indivi-
dual. None of the methods can identify the specifi c
individuals who have a nutrient defi ciency. Individu-
als with a nutrient defi ciency or excess can be identi-
fi ed only on the basis of biochemical or clinical
measures of nutritional status.

The second limitation is that all estimates of

dietary adequacy/inadequacy obtained by compari-

son with reference values for nutrient requirements

depend on how the estimate is derived (see

Chapter 7).

However, irrespective of the approach that is used

to assess dietary adequacy, unless the extent of under-

reporting is known and taken into account, the pro-

portion of individuals at risk of inadequacy will be

overestimated. While it may become possible to dis-

tinguish more reliably in population-based studies

valid from invalid reports of dietary intake, this still

does not enable population-based estimates of inad-

equacy to be made unless those who provide valid

intakes are also representative of the population as a

whole. All the evidence available to date suggests that

this is highly unlikely.

When the principal objective of a dietary survey is

to identify the proportion of the population who may

have inadequate intakes of energy and nutrients, it is

essential that the dietary intake information is inter-

preted in the light of appropriate biological measures

of nutritional status.

10.9 Assessing food intake

Nutritionists usually analyze dietary intake data by

converting the information on food intake into nutri-

ent intake using relevant food composition databases.

This approach simplifi es the process of analysis and

enables the resulting data to be compared with energy

and nutrient requirements (see Chapter 7). Describing

food intake in terms of foods rather than nutrients

presents two practical diffi culties that do not exist

when food intake is analyzed in terms of nutrients.

First, the variety of foods consumed is much greater

than the range of nutrients for which food composi-

tion data are available. Second, while essentially all

individuals in a group contribute to nutrient intake

data, not all individuals contribute food data for all

foods, i.e., not all individuals are “consumers” of the

same foods.

There are, however, several uses for which informa-

tion on food intake is more relevant or for which

information on food intake is needed in conjunction

with data on nutrient intake. For example, food regu-

latory authorities and agencies concerned with food

safety and nutritional surveillance require data on the

Table 10.7 Nutrient intakes in low energy reporting (LER) and non-LER
adults in the 1995 Australian National Nutrition Survey

Nutrient LER
(n = 1291)

Non-LER

(n = 9451)

Total

(n = 10 851)

Energy (MJ) 4.62 10.19 9.24
Protein (g/MJ) 11.0 9.8 9.9
Fat (g/MJ) 8.1 9.0 9.0
Starch (g/MJ) 15.9 14.9 15.0
Sugars (g/MJ) 12.9 12.4 12.4
Vitamin (μg/MJ) 159 122 127
Ribofl avin (mg/MJ) 0.26 0.22 0.23
Folate (μg/MJ) 37 28 29
Vitamin C (mg/MJ) 19 13 13
Calcium (mg/MJ) 106 90 92
Iron (mg/MJ) 1.8 1.5 1.5

Data used from the Australian Bureau of Statistics (abs.gov.au) (ABS,
1998).