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close this bookProtein-Energy Requirements of Developing Countries: Evaluation of New Data (UNU, 1981, 268 p.)
close this folderProtein requirements-children
close this folderProtein requirements of Filipino children 20 to 29 months old consuming local diets
View the document(introduction...)
View the documentObjective
View the documentExperimental details
View the documentSummary of main results
View the documentConclusions and comments

Experimental details

1. Subjects
Two sets of, respectively, three and four Filipino boys, 18 to 26 months old, were recruited from welfare institutions. During the first month of confinement in the metabolic unit of the Food and Nutrition Research Institute in Manila, their weights were adjusted to at least less than 10 per cent of their normal weight for height. Their characteristics are given in table 1. Five boys were mildly undernourished, i.e., they were 10 per cent below the ideal weight for their age, based on Philippine standards. They also had low weight for their heights. All children were 2.7 to 14.4 cm below the ideal height for their age. Two boys had light infestations of Trichuris trichiura (800 to 900 ova/al and very light infestations of Ascaris lumbricoides (2,200 to 2,400 ova/g).

2. Study Environment
The children lived in a metabolic unit in Manila throughout the study.

TABLE 1. Characteristics of the Subjects

Subjects

Age (months)

Body wt. (kg)

Ht. (cm)

Hgb. g/100 mg

Hct. vol. %

Serum albumin g/100 ml

Vit. A mcg/ 100 ml

Classification by wt.

R.A.*

26

10.3

82.5

       

1

A.C.

18

8.9

77.4

       

M.C.

20

8.7

73.6

       

G.L.

26

11.6

83.1

10.2

32

-

12

J.M

20

8.9

77

12.1

36

2.89

39

C.S.

23

12.3

86.5

14.5

42

3.01

16

N

R.A., Jr.**

24

10.3

82.3

11.5

36

3.23

24

* Ascaris lumbricoides 2,200/g; Trichuris trichiura 900/g.
** Ascaris lumbricoides 2,400/g; Trichuris trichiura 800/g.
1 Degree of undernourishment: 1° = - 10 per cent underweight.
2 N - normal.

TABLE 2. Diet Composition per 100 kcal

Food Grams Food Grams
Rice 14.0 Squash 2.5
Spanish makerel 3.1 Banana or 3.0
Sweet potato 5.0 Papaya 6.0
Bottle gourd 5.0 Coconut-corn oil 31.0
Sponge gourd 2.5 Sugar 1.7

3. Duration of the Study
Fifty-seven days for three children who ate six levels of dietary protein, and 47 days for four children who ate five levels of protein.

4. Diets
Diets were based on rice, fish, vegetables, and fruits habitually consumed in the Philippines (see table 2). The diets were calculated to provide 110 keel/kg body weight/day, based on the observed amount of energy consumed ad libitum during the first month of confinement in the metabolic unit. A blend of 50:50 coconut oil and corn oil provided 30 per cent of the energy intake. Three meals and two snacks were served during the day.

Vitamin and mineral supplements were provided each day: Vitamin A (3,000 I.U.) 0.9 mg; vitamin D2 (400 I.U.) 10 mcg; vitamin C 50 mg; thiamine 1.5 mg; riboflavin 1.2 mg; pyridoxine 1 mg; vitamin B 12 3 mcg; nixinamide 10 mg; iron 3 mg; iodine 75 mcg; calcium 40 mg; phosphorus 43 mg; magnesium 3 mg; manganese 0.5 mg; zinc 3.071 mg; choline 5 mg; dexpanthenol 5 mg; and inositol 5 mg. In addition, two teaspoons of Cetrin were given daily. Each 30 ml contains 250 mg vitamin C. Water was maintained at 80 ml/kg body weight/day.

Three children were fed six levels of protein, starting with 2.0 g/kg body weight/day and gradually decreasing to 1.75, 1.5, 1.25, 1, and 0.75 9. The other four children were given five protein levels starting at 1.75 g/kg/day. One-third of the dietary protein was provided by fish. Adjustment in protein level was done by replacing protein calories with starchy roots, fruits, or rice noodles (mung bean starch). Each dietary protein level was fed for seven days with a three-day break of ad libitum feeding between two consecutive experimental levels.

5. Indicators and Measurements
a. Nitrogen balance: Apparent nitrogen balance was calculated during the last four days of each seven-day period. Daily urines, two-day pooled faecal specimens, and dietary aliquots were analysed using a macro-Kjeldahl method. Apparent nitrogen absorption was calculated from dietary and faecal nitrogen. Biological value was calculated by dividing the percentage of nitrogen retained by the apparent absorption.

b. Protein requirements: An allowance of 10 mg N/kg/day was made for integumental and miscellaneous nitrogen losses to calculate the true nitrogen balance. The group's mean nitrogen requirement was calculated as the zero-balance intercept from the regression equation of true nitrogen balance (Y) on nitrogen intake (X), pooling all data points. The safe level of protein intake was calculated from the upper 95 per cent confidence band.

c. Urinary creatinine and urea nitrogen: These were determined by Folin's method and by a modified Van Slyke and Cullen method, respectively.

d. Anthropometry: Body weights were taken daily every morning before breakfast, post-voiding, with minimal clothing. The following measurements were obtained on day 0 and day 10 of each dietary period: height; arm, waist, chest, and head circumferences; and tricipital and subscapular skin-fold thicknesses.