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close this bookProtein-Energy Requirements of Developing Countries: Evaluation of New Data (UNU, 1981, 268 p.)
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close this folderA note on energy utilization and its efficiency
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close this folderCapacity of the Chilean mixed diet to meet the protein and energy requirements of young adult males
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close this folderProtein requirements for young Colombian adults consuming local diets containing primarily animal or vegetable protein
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close this folderProtein requirements of young Chinese male adults for ordinary Chinese
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close this folderProtein requirements of young male adults with a rural Mexican diet
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close this folderThe evaluation of soy protein isolate alone and in combination with fish in adult Japanese men
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close this folderProtein requirements of adult Thai males
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close this folderEvaluation of the nutritive value of a rice-and-bean-based diet for agricultural migrant workers in Brazil
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close this folderProtein requirements-adults, other protocols
close this folderProtein quality of rice-and-bean diets with or without protein and energy supplements to estimate protein requirements in young adult humans
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close this folderProtein needs of young adult men fed common beans (phaseolus vulgaris) in combination with starch, plantain, maize, or rice
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close this folderObligatory nitrogen losses-adults
close this folderObligatory urinary and faecal nitrogen losses in young Chilean men fed two levels of dietary energy intake
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close this folderProtein absorption of adult men with intestinal helminthic parasites
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close this folderAbsorptive capacity of adult Guatemalan rural males living under different conditions of sanitation
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close this folderStudies of energy intakes, expenditures, and requirements in China
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close this folderObligatory and integumental nitrogen losses - children
close this folderObligatory nitrogen losses and factorial calculations of protein requirements of pre-school children
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close this folderIntegumental nitrogen losses of pre-school children with different levels and sources of dietary protein intake
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View the documentThe protein requirements of normal infants at the age of about one year: maintenance nitrogen requirements and obligatory nitrogen losses
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close this folderProtein requirements of Filipino children 20 to 29 months old consuming local diets
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close this folderProtein requirements of pre-school children: milk and soybean protein isolate
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close this folderCapacity of habitual Guatemalan diets to satisfy protein requirements of pre-school children with adequate dietary energy intakes
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close this folderEnergy requirements of pre-school children and effects of varying energy intakes on protein metabolism
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close this folderRecommended dietary energy intakes for the first six months of life
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close this folderProtein-energy requirements-adults
close this folderInterrelationships between effects of protein and energy intakes on nitrogen utilization in adult men
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close this folderRecommended dietary amounts of energy for pregnancy and lactation in the United Kingdom
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Summary of main results

1. Food Intake
Although there were differences among children, on a group basis food intake did not differ significantly from week to week. Febrile episodes were usually accompanied by anorexia, resulting in diminished food intakes. In most cases these episodes were followed by a transient increase above the food intake preceding the illness.

2. Growth
Table 4 and figure 1 show the anthropometric changes. a. Weight: One child (402) did not gain weight and two (401, 410) gained at a rate slower than the 0.45 to 0.50 g/kg/day expected for healthy children of the same height-age. In contrast, two children (404,405) gained weight at more than twice that rate. b. Height: Five children grew at the expected rate of 0.30 to 0.34 mm/day. The other six children grew more (0.43 to 0.64 mm/day). This resulted in some catch-up growth, as shown in figure 2. c. Weight-for-height: Maximum individual changes were + 3 per cent. There were no changes on a group basis. d. Other anthropometric measurements: A small decrease in tricipital skin-fold thickness resulted in a slight increment of lean arm diameter, since there were no changes in arm circumference.

3. Protein Intake, Digestibility, and Balance
Figure 3 and table 5 give the individual and group data. Protein intake accounted for 8.8 1.1 per cent of the net dietary energy. Mean protein intakes were high (1.75 0.22 g/kg/day), and apparent digestibilities were about 72 5 per cent, greater in period I than 11 by 3 per cent. "True" digestibilities were about 7 per cent higher than apparent digestibilities. The average amount of protein "truly" absorbed was 1.46 0.17 g/kg/day.

TABLE 4. Average Values and Rates of Change in Anthropometric Measurements and CHI of 11 Children during Periods I and II

Average values Period I Period II Mean of I and II Paired t
I vs. II a
Weight (kg) 11.98 0.80*b 12.12 0.89 12.05 0.83 2.367
Height (cm) 84.5 4.3* 85.7 4.3 85.14.2 6.120
Weight-for-height 1%)c 994 1005 994 0.810
Arm circumference (cm) 16.10.8 16.00.9 16.0 0.8 0.088
Lean arm diameter (cm)d 42.9 1.5* 43.61.6 43.2 1.6 3.169
Subcutaneous skin-fold thicknessese 17,63.1* 16.53.2 17.0 3.1 2.300
CHI (units)f 800.13 0.820.12 0.82 0.12 1.847
Rates of change  
Weight (g/day) 10.6 8.7 3,7 6.4 7.28.2 1,987
Weight (g/kg/day) 0.870.70 0.290,54 0.580.68 1.955
Height (mm/day) 0.41 0.16 0.46 0.23 0.43 0.12 0.565
Lean arm diameter (mm/day) 0.02 0.04 0.02 0,04 0.02 0.02 0.140
Subcutaneous skin-fold thicknesses (mm/day) - 0.01 0.06 - 0.04 0.03 - 0.03 0.04 1.342
CHI [units/Period) 0.035 0.103 0,011 0.106 0.023 0.103 0.812

a For 10 degrees of freedom p<0.05 = 2.228 and p<0.01 = 3.169.
b Mean standard deviation,
c Weight expected for height: 100 per cent = 50th percentile of Boston standards.
d Corrected for subcutaneous skin-fold thickness.
e Sum of 3 sites: tricipital, subscapular, and paraumbilical.
f Creatinine-height index calculated from urine excreted on days without meat ingestion.
g Weight changes calculated by- individual regression analyses over 28 days. All other changes by individual differences between days 0 and 28 [Period 1) and between days 28 and 56 (period 11).
* Mean values of the two periods differ (see paired t value),



FIG. 1. Cumulative Anthropometric Changes-Periods I and II (11 children)



FIG. 2. Curves of Height Growth



FIG. 3. Nitrogen Balance Study

 

TABLE 5. Metabolic Balance Studies and Energy Expenditures in Periods I and II

 

(11 Children) a

 

Period I

Period II

Mean of I and IIb

Paired t I vs IIb

Protein        
Protein intakec (g/kg/day)

1.85 0.19 d

1.85 0.25

1.85 0.22

0.183

Apparent digestibility (%)

73.6 4.6*

70.6 4.7

72.1 4.8

3.100

"True" digestibility e (%)

80.4 4.6*

77.4 4.7

78.9 4.8

 
Nitrogen balance f (mg/kg/day) 98.0 20.6

82.3 20.6

90.2 2.16

1.905

 
p% g (% energy)

8.6 0.9

8.9 1.3

8.8 1.1

1.847

Energy  
Gross intakeh (kcal/kg/day)

93.6 4.6

90.9 4.8

92.3 4.8

1.415

Apparent absorption, (%)

91.9 1.6

91.2 1.7

91.6 + 1.6

1.326

Net intakei (kcal/kg/day)

85.9 4.3

83.2 4.8

84.6 4.7

1.383

Total energy expanditure j (kcal/kg/day)

76.6 8.6

73.0 6.3

74.8 7.6

2.188

Energy balancek (kcal/kg/day)

8.2 10.1

9.7 6.2

9,0 8.2

0.589

Basal energy expenditure,  
(kcal/kg/hr)

-

-

1.33 0.25

-

(kcal/m /fur)

-

-

54.2 5.4

-

a. Balance data and digestibilities calculated from intakes and excrete collected seven times at 4-day intervals in each 28-day period.
b. For 10 degrees of freedom p.<0.05 = 2.228 and p<0.01 - 3.169.
c. Protein = nitrogen (Kjeldahl) x 6.25.
d. Mean standard deviation.
e. "True" digestibility calculated assuming obligatory faecal nitrogen loss of 20mg/kg/day.
f. Nitrogen balance [apparent) = intake —urinary excretion —faecal excretion. No allowance made for sweat and other insensible losses.
g. P% = proportion of dietary energy derived from proteins = (protein intake, g x 4) + net energy intake x 100.
h. Gross energy intake determined by bomb calorimetry of the foods ingested.
i. Net energy intake = gross intake—faecal energy (bomb calorimetry).
j. Total energy expenditure calculated from heart rate and the corresponding heart rate—energy expenditure relationship during 14 hours of the day 16 a.m. to 8 p.m.) and from basal energy expenditure during 10 hours (8 p.m. to 6 a.m.)
k. Energy balance = net intake —urinary losses 15 kcal/g urinary nitrogen) -- sweat losses 18 kcal/g sweat nitrogen = approximately 0.1 kcal/kg/day)—total energy expenditure.
* Mean values of the two periods differ (see t value).

Apparent nitrogen balance was also high. All children retained at least twice the amount estimated for normal growth and to compensate for insensible losses (about 15 plus 9 mg N/kg/day, respectively).

Figure 3 indicates that only two children (405, 411) had protein intakes below the population estimates given in table 1. Their P%'s were also the lowest in the group, and their apparent digestibilities were near the group mean. Child 405 had the lowest nitrogen balance and child 411 retained 70.5 mg N/kg/day in period 11 when his intake. was only 1.36 9 protein/kg/day. Neither child had clinical signs of protein deficiency, both grew well, and their CHI, haemoglobin concentrations, and other biochemical measurements did not differ from the group. Child 404 had the highest food and protein intakes and the highest P% of the group. He had a high faecal output and his apparent nitrogen digestibility was 64 per cent in both periods of the study. As a result of this, he absorbed 1.46 9 protein/kg/day in the two periods and his nitrogen balance was only 53.1 mg N/kg/day in period 11; in period I it was 92.3 mg N/kg/day.

4. Basal and Total Energy Expenditure
Each child's basal energy expenditure varied little throughout the study. Therefore, each child's mean value was used to compute his total energy expenditure. Table 5 shows the group's basal expenditure. Child 414 was higher than the rest, with 67.2 kcal/m2/hr (2.88 kcal/kg/hr). Basal expenditure varied among the other children from 47.7 to 58.4 kcal/m2/hr (2.11 to 2.65 kcal/kg/hr). These values agree with those of similar children measured by the same method.

Figure 4 shows the range of individual total daily energy expenditures. The average daily energy expenditure did not vary between periods and the medical and nursing staff did not notice changes in the pattern or duration of the children's physical activity, except when they were ill.

5. Energy Intake, Absorption, and Balance
Figure 4 and table 5 give the individual and group data. Gross intakes during the days of excrete collection ranged from 85 to 100 kcal/kg/day. These were to a certain extent independent of total food intake during period 1, since the energy density of each child's diet was adjusted when the preceding week's intake was not between 87 and 97 kcal/kg/day. Apparent absorptions had a low coefficient of variability (1.7 per cent), and, except for child 414 who absorbed 88.6 per cent of the energy ingested, ranged from 91 to 94 per cent. Net energy intakes were, on the average, 8.4 per cent lower than gross intakes.

The estimates of urinary and sweat energy losses varied from 0.8 to 1.1 kcal/kg/day. Total daily energy expenditures and the energy balance results coincided with those from another study with similar children and equivalent dietary energy intakes. The energy balance ranged between-7.6 and 24.6 kcal/kg/day in period 1, and between -4.8 and 21.2 kcal/kg/day in period 11 (see figure 4).



FIG. 4. Energy Expenditure and Balance Studies

TABLE 6. Blood Chemistry and Haematology during Periods I and II

   

Days on the study

   

0

18

36

54

Packed red cell volume %

36 2*

35 2**

37 1

37 2

Haemoglobin g/dl

12.4 0.8

12.2 07

12.40.6

12.3 0.6

Plasma proteins g/dl

7.2 0.4

7.0 0.4

7.1 0.3

6.8 0.4 t

Serum albumin g/dl

3.8 0.6

4.1 0.6

3.8 0.4

3.7 0.7

Serum amino acid ratio non-essential/essential  

1.68 0.44

1.61 0.40

1.38 0.31

1.42 0.35

* Mean + standard deviation, n = 11.
** Lower than on days 36 and 54. F (3,40) = 3.072, p < 0.05, L.S.D. = 2.
t Lower than initial (day 0) values, student's paired t = 3.253, p < 0.01

6. Haematological and Biochemical Analyses
Table 6 gives the results of the analyses performed on blood, serum, and plasma. Analyses of variance indicated a small, transient decrease in packed red blood cell volume on day 18 (p < 0.05). The analysis of variance did not show differences among the other haematological and biochemical determinations. However, the paired comparison of initial and final values indicated decrease in total plasma protein concentration (p < 0.01 ) not accompanied by a decrease in albumin concentration.