|Protein-Energy Requirements of Developing Countries: Evaluation of New Data (UNU, 1981, 268 p.)|
|Research papers: Protein requirements-adults, standard protocols|
|Protein requirements of young Chinese male adults for ordinary Chinese|
Table 4 and figures 1 and 2 show the nitrogen-balance data. All men were in negative nitrogen balance at an intake of 0.45 and 0.55 9 protein/kg in the mixed diets, and also at the 0.35 g level of egg protein/kg. At higher protein intakes, some subjects achieved positive nitrogen balance (figures 1 and 2).
The mean protein requirements for the mixed Chinese diet and the egg diet were 0.79 and 0.61 g/kg/day, respectively. The 97.5 per cent confidence limits for the requirements were calculated as 1.18 and 0.89 g/kg/day, respectively. The efficiency of utilization of the Chinese mixed dietary protein was 77 per cent that of the egg protein, based on relative nitrogen requirements.
TABLE 3. Composition of the Experimental Egg Diet
Levels of protein intake
|Mung bean noodles||200||200||200|
|Vitamin and mineral supplements2|
|Nutrients: Protein (gm)||21||27||33|
|Calculated calories (kcal)||2,591||2,556||2,520|
1 See footnote 1 in table 2.
2 See footnote 2 in table 2.
The actual energy intakes of the subjects in the two series of studies ranged from 38 to 46 kcal/kg. Most of the subjects spent a large part of their time in academic studies and their energy expenditure was light to moderate. When a body-weight increase of more than 0.2 kg or a decrease of more than 0.7 kg occurred, an adjustment in energy intake was made by subtraction or addition of soybean oil. Changes in body weight over the 56-day period ranged from -2.5 to +0.6 kg.
Conclusions and Comments
TABLE 4. Daily Nitrogen Balance Data1 with Chinese Mixed Diets and Egg Diets
|Nitrogen intake||Urinary nitrogen||Faecal nitrogen||Skin nitrogen||Total nitrogen loss||Nitrogen balance|
(mg/kg body weight/day)
Chinese mixed diets
|121.0±0.87||99.0± 9.12||16.7±325||5.5±1.46||121.2± 8.16||- 0.2± 7.97|
|56.3±0.74||54.8+ 8.41||13.9±2.35||8.4±3.10||77.1± 9.50||-20.8± 9.11|
|71.7±0.78||63.9± 9.76||13.1+2.39||10.5±4.28||87.4± 8.56||-15.7± 8.95|
|89.0±1.37||71.5± 7.53||14.5+2.38||6.8+2.44||92.7± 8.41||- 3.7± 7.94|
1 Mean ± S.D. of 15 subjects.
TABLE 5. Calculated Biological Value (BV), Net Protein Utilization (NPU), and True and Apparent Digestibility of the Test Dietary Proteins at Different Levels of Intake in Young Men
|Level of protein intake||BV1||NPU1||
1 Mean +S.D. (n = 15).
a,b Same letters within a column are not significantly different.
A F ratio obtained from ANOVA test is significantly lower (P<0.01) than those in egg diet series.
c-f Group means within a column followed by the same letter are significantly different: c,e, p<0,01; d,f, p<0,05.