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Adult protein requirements- long-term studies


13. Long-term protein-energy requirements of six young adult Korean men
14. Long-term evaluation of the adequacy of habitual diets to provide protein needs for adult Thai men
15. Long-term protein requirements of adult Filipinos consuming local diets at two levels of energy intake
16. Long-term evaluation of the capacity of a chilean mixed diet to meet the protein-energy requirements of young adult males


13. Long-term protein-energy requirements of six young adult Korean men


Jin Soon Ju

Department of Nutrition and Biochemistry Korea University, Medical College, Seoul, Republic of Korea

Objective

To evaluate the long-term metabolic response of free-living Korean subjects consuming local protein sources fed at, or slightly below, habitual intake.

Experimental Design

Environment

Subjects were free-living, but consumed diets in the metabolic unit. Temperature ranged between - 2 to 28 C Specific values during each dietary period are given in table 1.

Subjects

Six male medical students aged 23 to 25 years served as subjects. Their characteristics are described in table 2. They were "healthy" as determined by medical exam and routine clinical laboratory tests. They belonged to the Korean middle class.

Diets

The diet consisted of natural foods and was based on customary intake as identified by surveys. The composition of the diet is given in table 3. Animal protein ranged between 25 to 30 per cent of total. Three meals per day were given. A vitamin supplement was given daily to meet recommendations.

TABLE 1. Environment and Duration of the Study

Period Duration Season Outdoor Temperature Feeding
I 26 August to 17 October 1980 (51 days) Late summer to middle autumn 20-26 C (22) Local diet at metabolic unit
II 19 October to 6 December 1980 (48 days) Middle autumn to early winter - 2-20 C (14) Local diet at metabolic unit
III 4 March to 25 April 1981 (53 days) Early spring to middle spring 5 12 C (8) Local diet at metabolic unit

Three 50-day periods following the design shown in table 6 were used to test the protein-energy adequacy of the diets. Energy content was calculated from proximate composition using the Atwater factors. Protein content was calculated from N analysis of ingredients.

Measurements Taken

Urinary nitrogen excretion was measured daily. Faecal samples were pooled for the first five days of each week. N balance was computed using 5 mg N/kg for skin and miscellaneous losses. Weight was measured daily.

Results

The main results are summarized in table 4, which shows the response for each subject per period. Table 5 shows the mean response for all periods.

TABLE 3 Composition of Experimental Diets (g/day)a

Food Amount (9)
1 Rice 286-319
2 Barley 20-23
3 Noodles 2-21
4 Bread 69-109
5 Rice cake 71-88
6 Potato 45-83
7 Soy-bean curd 34-45
8 Soy-bean paste 10-16
9 Soy sauce 22-25
10 Radish pickle 6-7
11 Radish, fresh 76 99
12 Carrot 0-13
13 Spinach 38-2
14 Cabbage 0-16
15 Cucumber 0-23
16 Green pepper 0-9
17 Green onion 23-32
18 Pumpkin 0-23
19 Garlic 7-18
20 Kim-chi (seasoned vegetable) 146-156
21 Apple 86-100
22 Pear 43-57
23 Seaweed 2-3
24 Jam 29-37
25 Tomato ketchup 0-19
26 Drink, carbonated 0-24
27 Egg 23-43
28 Milk 107-154
29 Beef 33 48
30 Sausage 18-23
31 Fish, pollack 0-7
32 Card-fish 6-7
33 Fish jelly 0-17

a. "Multivitamin" Tablets (Vita-fresh Vitamin Co, Inc., Garden Grove, Calif., USA) was given once a day in addition to the diet

TABLE 4 Summary of Metabolic Response (Mean + SD)

Subject Exp. (kg) Body Weight (kg) Kcal Intake (mg/kg) N Intake (mg/kg) Unne N-out (mg/kg) Faecal N-out (mg/kg) N Balance Protein Absorption Rate (%) Range Mean Other Observations
1 I 60.34 42 + 3 196 16 129 34 25 11 36 40 79-92(87)  
II 60.59 39 2 170 11 140 + 29 23 3 5 + 30 84 89(86)  
III 62.14 39 1 183 7 135 20 23 4 19 21 84-89(87)  
2 I 54.35 48 2 230 18 165 18 43 7 17 24 79-83(81) Examination stress
II 55.00 45 2 201 18 176 25 39 7 - 23 15 74-85(81) fourth week
III 54.87 44 2 218 11 174 24 34 6 6 24 80 88(84)  
3 I 71.25 37 1 172 9 141 27 23 7 - 2 35 80-89(87) Mother hospitalized
II 71.45 34 1 150 + 6 134 17 24 5 - 15 14 82-87(84) Mother died third week
III 70.96 37 2 184 11 156 21 32 4 - 5 17 81-84(83) Fourth week Gl trouble digest.
4 I 57.94 42 3 173 12 128 24 34 8 6 22 74-85(80) Examination stress
II 57.96 41 4 204 2 169 20 48 6 - 22 28 73-82(76) fourth week
III 58.21 43 3 189 12 147 19 39 9 - 5 19 72-85(78) Cold fifth week
5 I 57.70 45 2 183 6 145 27 38 12 - 11 30 72-39(79) Examination stress
II 58.42 42 2 213 11 174 21 41 11 - 8 21 73-86(81) fourth week
III 59.41 42 2 222 11 164 24 32 6 18 233 82-88(86)  
6 I 66.73 38 + 2 156 6 128 28 33 5 - 6 20 74-82(79) Examination stress
II 65.84 38 + 1 190 8 163 17 34 + 4 - 13 4 78-85(82) Dental inflammation
III 64.57 38 + 3 200 17 160 20 38 10 - 1 + 30 69-86(81) Dental abscess third and fourth weeks

TABLE 5. Individual Mean Metabolic Response for the Three Periods

Subject N

Body Weight (kg)

Energy Intake (ma Nlkg)

Protein Intake (ma N/kg)

Urinary N-out (ma N/kg)

Faecal N-out (ma N/kg)

N Balance (ma N/kg)

Protein Digestibility (%)

3 72 3 37 1 172 9 141 27 23 7 - 2 35 87
6 67 0 38 1 190 8 151 17 34 4 1 8 81
1 60 6 39 2 170 1 1 140 29 23 3 5 30 86
4 58.0 42 3 173 12 128 28 34 8 5 22 80
5 578 42 2 213 11 174 21 41 11 -8 21 81
2 54.9 44 2 218 11 174 24 34 6 6 24 84

TABLE 6. Experimental Design

Period Dietary Condition
I (52 days) Subjects 1, 2, 3 consuming ordinary protein levels. Subjects 4, 5, 6 consuming 15 per cent less protein than in ordinary diet.
II (49 days) Subjects 1, 2. 3 consuming 15 per cent less protein than in ordinary diet. Subjects 4, 5 6 consuming ordinary protein levels
III (53 days) Protein levels for each subject were selected according to data of experimental periods I and II.

14. Long-term evaluation of the adequacy of habitual diets to provide protein needs for adult Thai men


Kraisid Tontisirin, Kallaya Thongprasert and Area Valyasevi

Faculty of Medicine, Ramathibodi Hospital and Institute of Nutrition, Mahidot University, Bangkok, Thailand

Objectives

Recently, the N-balance response method has been used to determine the protein requirements of adult Thai men. The mean + SD requirement for egg protein of the subject was 0.81 + 0.05 g/kg/day. Since this value was obtained from a short-term N-balance study in a metabolic unit under a well-defined, experimental condition, further long-term testing under free-living conditions was required. Therefore, the objective of this study was to evaluate the adequacy of the recommended level of protein intake in adult village men consuming their habitual diet for a period of three months.

Experimental Design

Environment

The entire study was conducted during the period from mid-November 1980 to the end of February 1981 at Rai-Tai village in Ubon Province, north-east Thailand. The temperatures were 25.3 0.6, 22.8 0.6, 25.4 1.2C, and 28.3 2.2C during the months of November, December, January, and February, respectively. This was the cool season.

Subjects

Twelve adult village men participated in the study. They were apparently in good health, based on medical history, physical examination, complete routine blood count, urinalysis, and chest X-ray. Stool examinations were done before the beginning of the study and at the end of each month. Any ova or parasites found were recorded.

TABLE 1. Initial Characteristics of 12 Adult Thai Village Men

Subject

Age (yrs)

Weight (kg)

Height (cm)

LMAC (cm)

LMAMC (cm)

Skin-fold Thickness (mm)

Tricep

Subscapular

1B.B. 26 58.0 159.2 27.5 23.7 12.2 13.8
2 S.B. 21 50.1 159.0 25.0 22.2 9.0 12.8
3 P.N. 26 46.6 161.7 24.7 23.2 4.6 10.8
4 S.V. 19 56.9 166.0 27.0 24.7 7.4 10.4
5 K.P. 19 55.3 170.0 25.0 23.4 5.2 9.2
6 N.T. 23 57.4 165.4 27.3 25.2 6.6 11.8
7 P.S. 24 46.2 157.8 24.2 22.6 5.0 9.8
8 S.D. 19 58.0 1650 28.0 26.0 62 10.2
9 P.T. 19 45.6 159.0 23.3 21.2 6.8 7.4
10 P.P. 21 50.5 156.4 26.9 25.1 5.6 9.4
11 S.P. 19 51.6 164.5 24.0 21.6 7.7 7.6
12 T.C. 19 54.3 165.6 25.7 21.2 7.8 10.2
Mean 21 52.5 162.5 25.7 23.5 7.0 10 3
SD 2.7 4.7 4.2 1.6 1.5 2.1 1.9

The initial characteristics of the subjects are shown in table 1. The mean age was 21.1 years, weight 52.5 kg, height 162.5 cm. left mid-arm circumference 25.7 cm, and left mid-arm muscle circumference 23.5 cm. They were quite lean, as indicated by the thin tricep and subscapular skinfold thickness values of 7.0 and 10.3 mm, respectively.

Diets

The subjects were given a five-day menu of their usual diets throughout the study. The major components of the diet consisted of sticky rice, fish, papaya salad, green leafy vegetables, bamboo shoots, and pumpkin.

Initially the diets were calculated to provide an energy intake of approximately 45 to 50 kcal/kg/day. A protein intake of 0.81 g/kg/day was provided by rice and fish, with a ratio of 70:30. However, the subjects were allowed an ad libitum rice intake, while other protein sources of the diet were controlled. Therefore, the actual mean energy intake was decreased from 62 to 51 kcal/kg/day and protein intake varied from 1.31 to 1.07 g/kp/day during the three-month study. The actual ratio of protein intake provided by rice and fish was about 80:20. Reported energy intakes correspond to net values obtained by food-bomb calorimetry minus faecal energy loss as measured by bomb calorimetry minus faecal energy loss as measured by bomb calorimetry.

TABLE 2. Diet Record of Subject B.B. from Day 1 to Day 5

  Ingredients Amount (g) Energy (kcal) Protein (g) Fat (g)
Day 1 Rice (raw) 763.0 2,783.00 44.41 4 73
Dried fish 17.7 88.26 13.92 1.37
Mixed vegetables - 103.30 3.53 0.36
Soy-bean oil 1 4.5 130.50 - 14.50
Fermented fish sauce 20.8 18.60 0.72 0.11
Total   3,124.00 62.58 21.10
Dist. (%)     8.00 6.10
Day 2 Rice (raw) 808.8 2,950.00 47.07 5.01
Dried fish 17.7 88.26 13.92 1 37
Mixed vegetables - 97.20 3.17 0.62
Soy-bean oil 14.5 130.50 - 14.50
Fermented fish sauce 20.8 18.60 0.72 0.11
Total   3,285.00 64.88 21.61
Dist. (%)     8.00 6.00
Day 3 Rice (raw) 762.6 2,781.00 44.38 4.73
Fresh fish 73.4 80.01 13.92 0.76
Mixed vegetables - 79.40 3.33 0.40
Soy-bean oil 14.5 130.50 - 14.50
Fermented fish sauce 20.8 18.60 0.72 0.11
Total   3,040.00 62.33 20.50
Dist. (%)     8.20 6.10
Day 4 Rice (raw) 778.3 2,838.00 45.30 4.83
Dried fish 17.7 88.26 13.92 1.37
Mixed vegetables - 128.50 4.52 0.41
Soy-bean oil 1 4,5 130.50 - 14 50
Fermented fish sauce 20.8 18.60 0.72 0.11
Total   3,204.00 64.46 21 22
Dist. (%)     8.00 6.00
Day 5 Rice (raw) 694.7 2,534.00 40.43 4.37
Dried fish 17.7 88.26 13.92 1.37
Mixed - 72.20 3.44 0.45
vegetables 14.5 130.50 - 14 50
Soy-bean oil        
Fermented fish sauce 20.8 18.60 0.72 0.11
Total   2,844.00 58.51 20.80
Dist. (%)     8 20 6.60

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