Pediatric Nutrition in Practice

42 van Goudoever

Protein Requirement

The protein requirement is defined as the mini-
mum intake of high-quality dietary protein (see
Protein Quality) that will provide the means for
maintaining an appropriate body composition
and will permit growth at a normal rate for age,
assuming an energy balance and normal physical
activity.

Expression of Requirement

The protein requirement is expressed as the esti-
mated average requirement (EAR) or the average
requirement of the population. Due to lack of
conclusive data from empirical studies, the EAR
is calculated by a factorial method which includes
(1) the requirement for maintenance, estimated
from nitrogen balance studies in children, and (2)
the requirement for growth, estimated from rates
of protein deposition which are derived from
body composition analysis [4, 5] and the efficien-
cy of protein utilization for each age group.
The recommended dietary allowance (RDA)
is the safe level of intake which will satisfy the
protein needs of nearly all individuals (97.5%) in
the population. The RDA for protein is the EAR

• 2 times the standard deviation of the EAR of
  each age group.

Protein Requirements for Infants and
Children

Infants: 0–6 Months
Human milk is the optimal source of nutrients
for normal, full-term infants throughout the
first year of life and is recommended as the sole
nutritional source for infants during the first 4–6
months of life. The recommended intakes of
protein are based on an adequate intake (AI)
that reflects the mean protein intake of infants
fed human milk. For infants 0–6 months of age,

the average milk intake is 0.78 liters per day and

the average protein content of human milk is

11.7 g/l. Therefore, the AI of protein for infants

0–6 months of age is 9.1 g/day or 1.52 g/kg per

day.

Infants: 7–12 Months

During the second 6 months of life, solid foods

become a more important part of the diet of in-

fants and add a significant amount of protein to

the diet. The recommendation is for continued

feeding of human milk for infants through 9–12

months of age with appropriate introduction of

solid foods. The EAR and RDA are 1.0 and 1.2 g

protein/kg body weight per day, respectively ( ta-

ble 2 ).

Children: 1–18 Years

Protein requirements for older children are cal-

culated and recommended based on life stage

groups representing different velocities of growth

and endocrine status: toddlers (1–3 years), early

childhood (4–8 years), puberty (9–13 years) and

adolescence (14–18 years; table  2 ). During these

stages, there is a continuing but slow decline in

protein needs relative to weight. The EAR deter-

mined by the factorial method is set at the average

for boys and girls in each age group except ado-

lescence ( table 2 ).

Ta b l e 1. Indispensable, conditionally indispensable and

dispensable amino acids for humans

Indispensable Conditionally

indispensable

Dispensable

Histidine Arginine Alanine

Isoleucine Cysteine Aspartic acid

Leucine Glutamine Asparagine

Lysine Glycine Glutamic acid

Methionine Proline Serine

Phenylalanine Tyrosine

Threonine

Tryptophan

Valine

Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 41–45

DOI: 10.1159/000367868