Pediatric Nutrition in Practice

Nutrient Intake Values: Concepts and Applications 31

1

determine the relative turnover of polyunsaturat-
ed fatty acids [7].
The establishment of NIV for infants, chil-
dren and adolescents is further hampered by se-
vere limitations to the available scientific data ob-
tained from healthy children [8]. This is unfortu-
nate because infants, children and adolescents
have relatively large nutrient needs due to their
growth and development, and adequate substrate
supply is of utmost importance to support their
short- and long-term health, well-being and per-
formance [5]. Current reference values for nutri-
ent intakes vary considerably (see Annex 4.3),
partly due the limitations to the available scien-
tific database and partly due to major differences
in underlying concepts, definitions and termi-
nology [8].
Due to a lack of adequate scientific studies,
NIV for children are often based on observed nu-
trient intakes of groups of children in apparent
good health. However, this approach is weak, be-
cause it assumes that the subjects are in good

health and are achieving their full genetic poten-

tial and that their diets are quantitatively and

qualitatively appropriate and free from adverse

long-term effects. The concerns with respect to

this approach are strengthened by the recent evi-

dence on the long-term effects of early nutrition

on metabolic programming and the subsequent

risk of hypertension, obesity, diabetes mellitus

and cardiovascular disease in adult life [9–11].

The derivation of NIV from observed intakes

is a standard approach for infants during the first

6 months of life, when the intakes of breastfed

babies are considered an appropriate guide to op-

timal nutritional supply. However, this approach

has major limitations because the actual metabo-

lizable substrate intakes of breastfed infants are

not well determined. The volume of milk con-

sumed varies between about 550 and 1,100 ml/

day, and milk composition differs between wom-

en and with changes during the course of lacta-

tion, during the day and even during a single

feeding. Moreover, the bioavailability of sub-

Population reference

intake (PRI)

Average nutrient

requirement (ANR)

estimated median

of distribution

~97.5th percentile

or mean + 1.96 SD Upper nutrient

level (UNL)

highest level of daily nutrient

Frequency intake that poses no risk

Increasing nutrient intake

Fig. 1. Conceptual basis for NIV.

Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 29–33
DOI: 10.1159/000369234