Protein-energy requirements of prepubertal school-age determined by using the nitrogen-balance response to a mixed-protein diet13 Vivien

Gattas,

Gladys

A Barrera,

ABSTRACT

Short-term

vegetable-protein

mixed

tested

in eight

96,

128,

and

male

192

S Riumaio,

nitrogen-balance

diet

healthy

160,

Jose

mg

and

to a milk-egg

children

8-10

N

kg body

-

trogen

intake)

-68.3,

digestibility

was

respectively,

all in rng N

82%

when

and the

nitrogen

intake

mixed

diet

1 50 mg

ommended rived

the chronic

of

present retention;

safety

N

-

d. 160

kg

‘

-

d’;

the

97.5%

12.5%

protein

N

ofthe

-

kg

‘

-

population -

d

are adequate are needed

gram

We

for shortto evaluate

dates

Protein

requirements,

children,

recom-

the

international suggest

dren

should

have

conducted

mixed

diets

be can

Although

considerable

there

are virtually

no studies

needs

of school-age

tional

and

international

and

infants

the

and

adjustment

of individual

young

mixed

diets

of particular relevance lations in these areas and

with

size

such

based

prevalence

ofgastrointestinal

utilization

may

be further

these conditions (5, 6). Food and nutrition programs

with

school-age

established

Nutr

l990;52:

1037-42.

that or

Printed

This because animal

issue

multiple

these

findings

and

that from

report

provided

ad-

slightly

conducted Nations

a solid

consultation ofthis

dataon pro-

committee

review

to define

their

studies

meet

major

of United

expert excellent

and

the

of the

the

protein

pub-

topic

and

quality

of

study

was

vegetable

designed

ofprepubertal

the

nitrogen-balance

diet

boys

pattern

groups

to evaluate

mixed of protein

ofthe

urban

response

by

the

to meet using

the an

to graded

of a

experimental

consumption population

capacity protein-energy

diet

of the in Chile.

levels

ofdietary

The

low

so-

shortprotein

Protein under

emphasis

on the

in many

developing

©

American

1990

I From the Instituto de Nutricion y Tecnologia de Ia Alimentos (INTA), University ofChile, Santiago, and the Department of Pediatrics and the Human Nutrition Center, University of Texas Southwestern Medical Center, Dallas. 2 Supported in part by United Nations University Research Program and FONDECYT grant. 3 Address reprint requests to R Uauy, University ofTexas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235-9063. Received December 18, 1989. Accepted for publication February 14, 1990.

is

popuprotein

infections.

in USA.

from

others

vegetable

balance

and

is derived

(1). The

and

or

Less vegetable

compromised

a heavy

follows

for chil-

We

nitrogen

diet

approach

in the

protein

sources.

the sponsorship

an

published

predominantly

acids

pro-

provided

(1).

present

cioeconomic term

support amino

oppor-

(8). This

energy

of the dietary that

y Becas, malnu-

equal

strata

protein

animal

results

on an-

of Education

favoring

under

provides

a practical

requirements

emphasis

( 1-4).

requirements.

and

C/in

that

wheat,

1985

predominantly

values

soy,

of humans ofpredominantly

a high

J

egg,

The

visible.

the dietary

the Ministry

The

198 1 FAO/WHO/UNU

diets

The

of data

weight

an undue

economic

mixed-protein

requirements

in

mixed

na-

protein

on body

as milk,

have

Am

by most

intermediate

for developing countries ofthe world consume little

been

proposes

to predict the needs ofthis age available data evaluates the ca-

protein-energy

have

of protein

(1, 2). It is assumed

digestibility

population

lished

establishing

will have

protein requirements given to the ability

to fulfill

tein-energy

of adults,

is the interpolation

adults

for body

proteins,

beef, to meet the attention has been

dealing

for the

to investigate

taken

adequately

confirmed

and

the estimation

approach

adolescents

metabolic mass will be adequate group. In addition, most of the pacity

infants

age group

and

children

that

dedicated

ofyoung The

bodies for this

from

school-age

has been

addressing

children.

recommendations derived

effort

requirements

from showing

and

following

recommendations

studies

school-age nutritionally

accessible

process

50%

for most

de Auxilio Escolar program to prevent

1940s.

that

the world

University base

early

derived

digestibility.

throughout

the protein-energy

with

across

for essential for this

lower

Introduction

the

which

KEY

allowances

from

1960s,

justment

dietary

are

(7). In Chile

the learning

follows

requirements

WORDS

they

countries

optimize

targeted are the

are tailored

for the population

1990;52: 1037-42.

mended

because

consumption

and

tunities

Am J C/in Nutr

allowance.

been they

programs

of developed

trition

‘.

rec-

d.

rather

feeding

have because

through a specialized agency, Junta has implemented a school feeding

was de-

kg’

-

but

irnal-protein

on the

protein

programs

necessarily

school

models

(ni-

diets,

retention

is 1.2 g protein

Most

nitrogen

suggested

recommendations long-term studies

ofthis

mg

nitrogen

not

vulnerable

diet.

milk-egg

These

groups,

10 d while

Apparent and

received

to cover

a CV

conclude that term nitrogen

.

Uauy

countries.

received

for

on the milk-egg balance = 0.52

mixed

for satisfactory

allowance

by using

kg’

.

for the

subjects

Mean

was

86%

They

d

-

on the mixed diet and 160 mg N - kg . d The mean regression equation was nitrogen

Ricardo

response to a protein diet was

y old.

wr’

and

boys

Downloaded from https://academic.oup.com/ajcn/article-abstract/52/6/1037/4651177 by Univ of California Library - Bioscience & Natural Res Library user on 31 July 2018

Society

for Clinical

Nutrition

1037

1038

GATTAS

characteristics

and energy

intake

of boys participating

AL

The

Age

Weight

Height

ofthe

children

of the ipation

Weight-for-

Subject

ET

istration

TABLE 1 Anthropometric in the study

height6

Caloric

intake

kg

cm

%

kca/#{149} kg’

elected

not

1

8

26.4

119.5

122

85

2

8

25.5

129.5

97

90

3

8

25.7

125.5

105

82

4

10

28.7

124.0

123

73

the

to participate

in the

recreational

facilities

Two

types

ofdiets

were

30.0

135.5

101

72

26.2

128.5

106

80

7

9

27.5

130.0

103

76

8

9

25.4

123.5

108

90

tein

.

8.8

27.4

127.0

108

81

dients

for these

1.6

4.9

Table

2. The daily energy

Percent

of median

WHO

standard

used

to estimate

equilibrium

and

Subjects

the

7.1

diet

intake

required

for

the

nitrogen

(milk

growth.

male

prepubertal

They were nonprofit

Infancia,

which

for children Santiago, project

the

Chile.

preparation

8- 10 y old were

schooling

and

neighboring

A metabolic

of diets and

children

ward

were

its relevance

and

set

up within

were

discussed

organization and board of trustees. those who had home leave every interval allowed us to complete without The

and

hemoglobin,

laboratory and

initial

advised

Energy

were

which

carefully

consumed

their

maintained

under

throughout was recorded

and

visit

of

urinalysis.

Table

are also daily to ensure all urine

under

boys

included

Children

that

they

ofa

activity

ate only

feces

were

balance

for that

calculation of the The experimental

data

period

group mean. protocol was

were

and

were

and

the

institution.

an experimental

preparations

protein

intake

nurse

a diagnosis 3 d during

and the

from

the

reviewed

and use

approved

by the

y Tecnologia of humans

executive committee which oversees the

de as

of the admin-

Downloaded from https://academic.oup.com/ajcn/article-abstract/52/6/1037/4651177 by Univ of California Library - Bioscience & Natural Res Library user on 31 July 2018

mixed-protein

-

kg’

-

d’.

The

distribution

for each

are

child

was

ingre-

given

in

calculated

evaluation of 24-h dietary energy period. Vitamin and mineral sup-

as described

dietary

in Table

allowances were

and protein

2 to meet

(RDAs)

analyzed

or exceed

(1 1). All

for their

distribution

Mixed

ingre-

protein-energy

of mixed

and milk-egg

diet

Milk-egg

19.8

milk

Powdered whole Maltose dextrin Sugar

egg

diet

39.8 29.3

-

25.0 56.6

28.4 108.6

Oil

35.4

25.4

Margarine

45.0 33.4

47.2 133.6

Cornstarch

150.0

Bread

-

30.0

Marmalade Palm syrup Instant-drink powder Bean flour Rice Mashed potatoes Beefbroth Chicken broth

-

32.5 35.0 50.0 35.5 5.2 1.0

-

150.0

Vanilla pudding flavoring aids Fooddyes Animal protein Vegetable protein

9.0

For a child

6

30.00 50.0

-

Canned pears

or fever for > 1 d,

excluded

to

g/d

-

1.7

-

0.01 28.1 (100%)

-

7.0 (25%) 2 1 . 1 (75%)t aged 8-10

y with weight

(0%)

27.4 kg, height

127.0

cm, wt/

ht 108% ofstandard; total energy 2310 kcal/d. One multivitamin-mineral supplement tablet (Laboratories Pfizer de Chile, Santiago, Chile) supplied the

following:

riboflavin, 50

ethics committee ofthe Instituto de Nutricion la Alimentos (INTA) which supervises the subjects, and by the Nacional de la Infancia,

>

what

collected.

dietitian

of a physician

age were

ofphysical

and

the care

supervision

the

included. pattern

serum

I shows

of the

the child to establish illness persisted for

the

cx-

measurement

the physician examined treatment. If the febrile

experimental Patronato

schedule. by a medical

the study (10). The presence oftemperature daily and if the febrile illness persisted

period,

from This period

count,

that

food the

the

a hematocrit,

routine

supervised

to them

after

the parent-teacher

included

data

their

for the

institution

with

characteristics

intake

to continue

was provided They

complete

anthropometric

in the study. but

the

kitchen

free

monetary

intake, that is, 0.6, 0.8, 1.0, and and a controlled reference-pro-

Ingredient

Skim

in southeast

Children were recruited 2 wk or less frequently. an experimental diet

tests,

white-blood-cell

transaminases, and

a special

No

children or the families. The ofthe children by improving

fed at I g protein

and

was given

and

for

training

areas

interfering with the child’s home children were healthy as determined

amination

selected

practical-skill

semirural

nature

were

time.

students in a boarding school operated by organization, Patronato Nacional de Ia

provides

from

egg)

diets

TABLE 2 Average composition experimental diets6

Subjects Eight

and

recommended

dients

and methods

this study. a volunteer

used:

on the basis of a prospective intake recorded over a 1 -mo

(9).

protein

Individuals at any

at the

diet fed at four levels ofprotein 1.2 g protein - kg body wt - d

plementation was

ofthe

that their particinitially contacted

Diets

9

6

was conducted.

informed

study. study

available

10

9.5

the study fully

offered for the to the welfare

5

0.8

were

in the

6

SD

where

parents

participation

compensation was study did contribute

.

school

their

study and signed consent forms stating was voluntary. Almost 50% offamilies

terminate 3’

boarding and

mg;

retinol, 2 mg;

nicotinamide,

1.5

mg;

pyridoxine,

cholecalciferol,

1 mg;

12 mg;

25

cyanocobalamin,

calcium

pantothenate,

.tg; thiamin, 2 tg;

2 mg;

CuO), 70 Lg; iodine (as KI), 50 gig; iron, 1 mg; potassium Lg; manganese (as MnCO3), 29 g; magnesium (as MgO), zinc (as ZnO), 71 g.

t Derived other

3%.

from

wheat

31%,

potato

15%, bean

1 mg;

ascorbic copper

acid, (as

(as KI), 16 108 gig; and

16%, rice

10%, and

PROTEIN TABLE

ENERGY

NEEDS

3

Anthropometric

changes

in boys

participating

in the

study6

Protein Mixed Initial Weight(kg) Height (cm) Weight-for-height (%standardt) Weight-for-age (% standard) Height-for-age (% standard)

27.4 127.0

1.2g.kg’-d’ 1.6 4.9

± ±

27.6 128.3

108±9.5 95

95

95

96 ± 2.8

95 ± 2.5

t Reference

content energy

±

1.5 5.0

± 4.0

l.0g.kg#{149}d

27.7 128.3

106±9.1

1.7

±

27.7

± 4.9

106±8.5

1.4

±

130.4

± 5.3

103±

10.1

95 ± 3.5

94 ± 3.7

90 ± 4.0

96 ± 2.8

96 ± 2.8

96 ± 2.4

95 ± 2.5

the Kjeldalh nitrogen bomb calorimetry

determination (Gallenkamp,

and for London)

12).

lasted

dietary

period

for the

10 d. The

first

5 d were

last 5 d as the true of the

subjects

protein

balance

to the

diet

design.

was

experimental

period. four

ofeach

The

sequence

provided

66%

ofcalories

At lower

protein

intakes

equivalent calories Four meals and sumed

under

from

intake The

protein

close

ofthe mixed-protein reference-protein

diet

of the

were

by

ing minimal

HCI/L. urea,

clothing

daily

before

first morning urine. daily in 2-L plastic

and

volume

and

were

con-

At the

end

the control The total

methods

that

we

8 mg N - kg Anthropometric

previously

and height triceps,

to visit periods.

d

(I , 10). measurements weight and

and

subscapular

urine

(10,

analysis

the

to

True

nitrogen

fecal

nitrogen.

losses

were

taken

made

period.

mid-upper-arm thickness.

ofthe

start

of the

kg’ - d’) and for the mixed-

-

control

for total

(milk-egg)

serum

protein,

pro-

albumin,

used

dividuals

was data,

-

et al (14)

to estimate

mean

alternatively

for a group a CV

( 1,

Committee

inThe

from the group intake required

requirement

considering

FAO/WHO/UNU

the intake.

is expected to support for this age group. The

recommendations

on the

balance by using

establishing

was derived on a nitrogen

(1

by one-

nitrogen

vs nitrogen

kg . d ‘. This value its variability (2 SD)

based

done

was analyzed

balance

mean requirement responses based

to retain 10 mg N normal growth and approach

intake

by Rand

statistics

were

(1 3). The

ofprotein

of nitrogen

descriptive

groups

(ANOVA)

suggested

estimation ofthe mean ofindividual

of in-

+ 2 SDs

derived

of 12.5%

as used

14).

gain for compatible

weight,

as

in-

blood

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the the

to each

no effects

height, study

and

than

anthropometric

are shown

2-mo period with normal

dren. Concurrently, is slightly greater diet,

at the This

Results

assigned

circumFasting

by using diet

levels

regression

the

analyzed between

of variance

approach

dividual

Mean

according

were

at the

glucose, cholesterol, triglyceride, and heand for hematocrit and white-blood-

were

graded

to

throughout

for pos-

and

ofchildren

fat

diluted

12).

experimental

completion analyzed

Comparisons

by the

nitrogen,

frozen

markers

were

vein

(0.6 g protein protein intakes

voiding

was

for total

urinary,

gluteal,

after

wear-

collections were 10 mL of 6 mol

stored

nitrogen

of each

were

collected daily, pooled and marked with auto-

red

intake,

miscellaneous

and

were period,

described

from

at the end

the was

carmine

and -

sample Feces

and

and

was analyzed

balance

was calculated

Integumental

beginning

blue

breakfast

measured,

An extra

measurements. 5 d of each

brilliant

balance

was

they

24-h urine containing

L. A sample

creatinine.

sible repeat for the last claved

of3

eating

while

upon

obtained

response

as possible.

at 0700

Complete bottles

After the volume

to a total

way

from weighed

and They

lowest . d’)

analysis

Data

fat.

Measurements were

the antecubital

ofthe . kg’

cell count.

replaced

to visit

All children

from

urea, transaminases, moglobin concentrations,

mixed-

± SD).

Parents

their made

diet

period.

from

33%

were given egg protein.

as often

tein

and

66 d. Children were permitted between experimental diet

encouraged

protein

Statistical

duration ofthe study was their homes for weekends were

drawn

consumed

dietitian.

diet study, all subjects based on milk and

were

study and at the end highest (1 .2 g protein

constant energy

calories

supervision

samples

was kept nonprotein

from carbohydrates and fat. a snack were provided daily

the

the

a latin-square

the children

carbohydrates

the

for the

by using

period,

and

for the allocation

levels

randomly dietary

diet

as adaptation

protein-intake

established

At the end

mixed-protein

considered

during an ad libitum diet for 4 d. Energy throughout the experimental diet period.

ference,

±

diet

9.

by using by using

Each

cluded

27.6

128.5

109±8.9

3.2

±

0.6g-kg-d

0.8g-kg.d

27.8 ± 1.5 127.6 ± 5.1

106±8.5

4.0

±

1.4 6.0

±

Milk-egg

diet

l.0g#{149}kg#{149}d ±

intake

SD.

6

(10,

1039

OF CHILDREN

ofdiets

nitrogen became intake. Fecai nitrogen

weight which is of chil-

of 3.0 ± 1 . 1 cm, which groups were randomly

levels could

for the group average

g (. ± SD), in this group

for the mixed-protein

be anticipated

of diet effects ANOVA.

Individual values for urinary nitrogen balance, and apparent protein

an average Because

protein-intake

ofsequence

or other variables. This lack was verified by using one-way

4. Urinary

3. The

was 300 ± 360 growth expected

they grew expected.

ofthe

indices

in Table

nitrogen, digestibility

progressively was relatively

on

on growth

anthropometry

fecal nitrogen, true are shown in Table higher with increasing constant throughout

1040

GATTAS

TABLE 4 Nitrogen balance 8-10 y old

AL

the and digestibility

of mixed

and milk-egg

diets

in boys

lower

True nitrogen balance6

Focal nitrogen

Urinary nitrogen

Apparent digestibility %

mg.kg’.ct’

Mixed diet 96 mg#{149}kg.d

three

protein-intake

1.2 g protein/kg protein

Subject

protein

was

fully

protein

intake.

protein

diet

Fecal was

with

fed at the

highest

two

digestibility

pected

because intake

87.9

34.8

-34.7

64

Estimated

true

97.3

33.9

-43.2

65

tein

for the

3

78.4

27.0

-17.4

72

4t St 6 7

62.8 78.3 70.8 83.0

26.1 22.6 25.4 23.9

-0.9 -12.9 -8.2 -18.9

73 76 73 75

8

71.3

40.1

-23.4

58

for

81.4 10.2

30.8 6.4

-24.3 12.7

68 6.6

excretion;

83.9 94.3 100.0 95.4 86.0 84.0 86.9 100.7

3 4t 51 6 7 8

I

93.3

SD

76.

33.1

3.0

74

23.5 36.9 35.2 27.7 33.5 13.6

2.2 -16.9 -10.6 6.3 2.4 9.5

82 71 72 78 74 89

28.4

-9.1 -1.5

78

28.2 8.5

of 1 g/kg ance

I

95.6

33.9

-

3

20.6

4t

97.0

32.4

22.7

78 80

St 6 7

105.6 113.2 110.5

35.2 26.4 17.5

1 1.2 12.4 24.0

78 84 89

8

83.1

33.0

35.9

99.6 12.3

29.4 7.5

23. 1 8.4

79 82

-

SD 192

122.0 106.5

36.7 47.2

25.3 30.3

81 75

24.0

21.3

21.6 29.5

-21.8 -2.9

88 89 85

All

97.1

37.7

49.2

80

7

128.2

39.3

16.5

80

maintain

8

111.3

41.7

31.0

78

117.3 15.2

37.8 7.7

28.9 11.3

80 4.3

14.2

8.0

91

28.3

15.0

82

16.7

30.7

90

4 5 6 7

31.4 24.3 17.6 21.8

16.0 23.8 12.6 19.7

80 85 89 86

8

121.1

19.3

11.6

88

I SD

113.2 9.8

21.7 6.0

17.2 7.3

86 3.9

3

N intake

-

urinary

N

- fecal N -

miscellaneous losses). t Values excluded from group

8 mg

N

.

kg

-

d

(skin

illness

bal-

elevated

urinary

intake

high-quality

4, their

mean

values.

not

deviate

do

removed period are

animal-protein

-

and kg

fever

nitrogen

in Table of the

of protein

two

with

subject, 2, was temporarily concerns; data for one

the

are

diet,

all

all except one d’. The lowest

-

expected

for age.

nitrogen

presented

had ni-

subjects

balance

subjects.

response

as

The individual plotted; the re-

5 and

in Table

had

at 1.0 g prodiet.

intake. are also

coefficients

was

ofeight

Most

on the milk-egg diet isonitrogenous mixed

relationship

nitrogen values

± 7.5

balance

are

mg N or 0.94 to the

50% of the

all had

ranging

from

statis0.69

to

et al ( 14) was used other studies in the

by Rand data with not

linear

at the

The

mean

individual

kg’

highest

-

± 0.05

The

levels

regression

within

the

range.

The

for 97.5%

be lower

(requirements a predominantly own

-

kg’

data,

(1.03

CV

lowest

protein on the

were SUN diet

observed

diet.

d’.

On

This

(25%)

the

report around

data would

Thus,

-

d’.

5%,

cover

value

the

-

kg’

indices

The

ifwe

cor-

needs

basis

of

of rec-

(1), we used the maintethe requiregroup) would

use the variability

recommended

allowance

would

-

are presented

in the

150

the safe recommended

Alternatively, the

serum

was found for 0.6 g protein and the highest SUN was

milk-egg

-

to was

to cover 97.5% ofa population vegetable mixed-protein diet

g protein

Blood biochemical changes

± 2 SDs population.

requirement balance

to satisfy

group.

ments

mean

kg

.

nance

ofthe

daily

required

68.3

-

nitrogen

g protein

intake

individuals

d’.

intake)

wt positive

of the FAO/WHO/UNU CV for nitrogen-balance

of our

Downloaded from https://academic.oup.com/ajcn/article-abstract/52/6/1037/4651177 by Univ of California Library - Bioscience & Natural Res Library user on 31 July 2018

.

protein

be 1.18 g protein

I

N body

(nitrogen

ommendation 12.5% as the

allowance for using

and

0.52

=

in mg

a 10 mg/kg

responds

#{149}d 108.7 104.6 104.6 103.9 121.8 110.8

nitrogen

was

138.7

129.8

levels

correlation

two

for

prointake

1 .2 g protein/kg,

represented

graded levels of protein for the eight subjects

The

ofintake

184.2 157.4

1

are

0.95. The linear model suggested in this analysis to compare these

3

2

markedly

the normal

significant

4t St 6

I SD Milk-egg diet 160 mg. kg

which

literature.

increasing A protein

observed at that protein intake was 8 mg Nshould be considered adequate to sustain growth

parameters

tically

4.6

level,

1 shows the individual

spective

nitrogen

in positive

in the calculation

For

affected by the linear regressions

mg.kg#{149}d

1 2

d1,

with

intercurrent

data

mean. One for parental

up to twice

Figure

36.0

had

a lower nitrogen retention tein - kg’ - d than on the

-

95.4

intake

had positive nitrogen balance retention values > 10 mg N

-

rates

apis cx-

digestibility.

diet.

significant

at lower

retention

kg

protein

their

missing.

observed

-d.

included

the group the study

trogen

79

-

results

subjects nitrogen

6.6

22.5

-

Their

of

protein

increased

apparent

were

d’

-

milk-egg

ofendogenous

improved

all subjects

the

in the

a higher

the

kg

digestibility

intake

contribution giving

subjects

not

therefore

160 mg.kg-d 2

were

increase

balance

5, had

although

results

The

-

the mixed-diet

mixed-vegetable-protein

highest

4 d. These

from from

78

9.6

the

with

when

basis

when

an apparent

mixed-protein

lower

that

4 and

>

80%

10 rng N-kg’

During subjects,

near

only

1 .0 g protein

lowest

values

nitrogen

ensured

of>

was had

levels.

increased

an incremental

0.6 to

diet

increases

1

intake

from

as the

and

On

This

ofthe

as protein

fed.

nitrogen

fed.

86% compared parent

levels

were

digestible

2

I SD 128 mg-kg.d I 2

6

ET

initial

value

in Table

urea

nitrogen

kg’ found -

was

.

d for

higher

6. Significant (SUN).

The

on the mixed1 g protein/kg than

during

PROTEIN

ENERGY

NEEDS

0

OF

the

larger

value

metabolic

40

E UI

0

20

U

increase

variability

may

change

and

We propose

be

U

-60

the 96

128

NITROGEN

160

INTAKE

192

mg/k

show

that

the

FIG 1. Individual nitrogen-balance responses to graded levels of a predominantly vegetable mixed diet; four levels of nitrogen intake were tested in eight subjects. Solid lines indicate linear regressions, dashed line corresponds to a retention of 10 mg N, and symbols represent individual subjects. Table 5 provides the parameters of the responses.

ofthe

experimental-diet

customary protein

protein

intake

for

d.

Minor

statistically

kg

-

periods.

-

bumin and globulin were total cholesterol occurred.

10 d of feeding stable normal

the

for the

is consistent

children

specific

with close

individual

creatinine

within

was

in alin serum when an

vegetable-protein in mean value

Urinary

and

the

to 2 g

changes

Significant changes values were noted

diet.

study

being

significant

predominantly rise was observed

a milk-egg

throughout

these

noted. Lower

essentially cholesterol-free was consumed. A brisk

This

the

diet after

is partly

compensated

nitrogen

balance

oftwo

upper

need

these needs

range

of

frame

of this

data.

study

provides

mendations and

data

confirming

based

older

using

age-specific

boys,

on

subjects.

the

information

It also

a predominantly

on protein

adequacy

requirements recom-

from

younger

interpolated

served

to test

vegetable

the

appropriateness

mixed-protein

diet,

diets high in animal protein, in the feeding ofschool-age The nature of this study does not permit a definite regarding the long-term adequacy of the recommended intake

but

serves

recommended term

studies

initial

months

position,

and

to fully

dietary

assess

the

indices

response

to the

linear

portion

response.

The

of the

use

rather than the pooling of data preferred approach to analyze (1,

with this

6, 14),

intake

range.

The our

data

approach

considered

protein

a safe Longer-

is controlled

on growth,

body

status.

for

represents

yet

few

levels

in

resulting

variability

is smaller defines both

studies the

than a lower

alternative

of individual

have

actually

regression

evaluated

as

derived

by using used

safe recommended variability

factors

this

suggest

potential able

ofhumans

to attain

that in lean

nitrogen body

may

the

balance

may

and

lead

growth

effects

the

dramatic

intakes in adults

TABLE 5 Parameters for individual linear vegetable mixed diet on nitrogen

be positive

altered

plasma

of The

eventually

over

time,

on 0.356

to 45% of the recommendation the other hand longer-term studies mass

time

periods

epidemiological

showed

nitrogen

short

growth.

evaluating

equilibrium

is true, episodes

short

from

et al (15) to low

nitrogen

this

with

intakes

preclude Durkin

the extra by the in-

(1).

over

because

as proposed

considerations

that

intervals

interfere

protein

growth

vanwhere

infectious

affected

not

while serves and

stressors

Although

time

expected

do

nitrogen illness

for individual

when

not

was

to low

Although

losses

despite

g/

for the (3 mo)

significant

aminotransferases

regressions of nitrogen intake from balance for eight study subjects

r

Slope

I 2

3

four

Intercept

Intake6

mgN-kf’-ct’

4 5 6 7 8 I SD

approach

allowance.

only

recovery.

short

were

balance

linear

suggest

the and

conventionally; and

not

be sufficient

This

kg, which corresponds adult age group. On

lines

submaintenance-to-maintenance the variability

febrile

This fortuitous event of nitrogen horneostasis

first

vs ni-

points has been proposed these type of data by Rand

study.

Subject

a valid

nitrogen-balance

dramatically

negative

for environmental

over

at corn-

corn-

Nevertheless,

in evaluating requirements (1, 6). The four levels tested, above and below that required for nitrogen equilibrium,

trogen-intake

protein

children.

ofprotein

nitrogen-balance

correspond

others

effects

children. answer protein

to setting

for school-age

where

biochemical

the short-term

approximation

allowance

are required

several

approach slightly

as an

protein

than

‘ .

margin

during

not

repeated

adaptation Ethical

he was of

rather

d nature

sources loss

d).

developed

-

‘

also

indicators

nitrogen

adaptive

of present

kg

the higher

in children by the

who

a safety but

-

data

for the diets

nitrogen

kg

-

as evidenced

-

by

(1, 2). Our

However,

infections

subjects

presently

mixed-vegetable-protein

(1 g protein

the

would

recommended

utilization

urinary

of a

‘

safe;

to that

that

digestibility.

may

and

in children. This

is identical

in protein with

d

-

protein

from

utilization

growth

to decreased

of school-age

reference and

their

kg

-

difference

ofour

growth

are severe

further

considered

RDAs

balance

protein

chronic

Discussion

This

.

ofcommon

mechanism

balance

may

are highly prevalent. It has been suggested during infection may be fully compensated

negative

heights.

be

digestible

by lower

to provide

creased this

diet

Council’s

1 .2 g protein the changing

and

energy

Research

intakes

occurrence

affects

ability

d

-

loss observed

protein

The

The

remained

main

fecal

the

kg

-

nitrogen

consuming to underscore any

for a fully

is derived

parable

of

conditions

stresses

of 1.2 g protein

vegetable

National

evaluated

gid

because

by FAO/WHO/UNU

recent

conditions

Real-life

environmental

that an intake

1 .0 g protein

recommended

standardized

(1 , 2, 5-8).

amount

-40

the

variability.

ofrequirements

multiple

predominantly

equivalent

-20

because to reduce

requirements

mixed

m

tend

may

0

-I

be used

studies

modify

z

1041

CHILDREN

0.93 0.95 0.90 0.69 0.95 0.94 0.83 0.92

0.62 0.72 0.48 0.37 0.38 0.57 0.38 0.65 0.52 0.14

-85.7 -103.3 -67.2 -43.5 -46.7 -68.0 -46.5 -85.1 -68.3 21.9

154 157 161 145 150 137 150 146 150 7.5

We that

Downloaded from https://academic.oup.com/ajcn/article-abstract/52/6/1037/4651177 by Univ of California Library - Bioscience & Natural Res Library user on 31 July 2018

6

Intake

necessary

to maintain

a nitrogen

balance

of 10 mg

-

kg

-

d.

1042

GATTAS

TABLE 6 Laboratory

values

in boys participating

ET

AL

in the study6 Protein Mixed Initial

Hemoglobin (gIL) Albumin (g/L) Globulin (gIL) Serum urea nitrogen (mmol/L) Glucose (mmol/L) Cholesterol (mmol/L) Triglycerides (mmol/L) SD. Groups

6

t One-way

4.3 3.9 3.63 0.52 with different

analysis

of variance

( 16, 17). The measurement correlation with nitrogen

132 45 28.80

± ±

7

±

4b

±

3.80k

superscript

letters

132 45 27.20

133 ± 7 45 ± 3b 23.80 ± 320b

different,

P

nitrogen shows the decrease

good in ni-

reutilization with increasing nitrogen intakes. The highest values were found initially before study diets were fed; this agrees with the diet history data indicating an intake before entry be-

The

highest

the

milk-egg

is four

concentration diet

times

providing

the intake

we

this

period.

terol

values

(1 8). The

were

seen

used when

effect

it reflects

plasma

while

Research

because diet

because

on total

a cholesterol

National

controlled for

intake was observed

ommended sources

is of interest

ofcholesterol

effect

retention to assess

3b

±

4#{149}10b