Cover Image
close this bookProtein-Energy Requirements of Developing Countries: Evaluation of New Data (UNU, 1981, 268 p.)
close this folderObligatory and integumental nitrogen losses - children
close this folderObligatory nitrogen losses and factorial calculations of protein requirements of pre-school children
View the document(introduction...)
View the documentObjectives
View the documentExperimental details
View the documentSummary of the main results
View the documentConclusions

Experimental details

1. Subjects

a. Five children, all males, of mixed Maya and Caucasian descent (Lading).
b. Chronological age: 24 5 months (range: 17 to 31). Height-age: 16 5 months (range: 10 to 23).
c. All had been treated for severe, oedematous protein-energy malnutrition (kwashiorkor and marasmickwashiorkorl. They had recovered fully at least one month before beginning the studies, based on clinical, anthropometric, and biochemical criteria (plasma proteins, non-essential/essential amino acid ratio, haematological indices, urinary creatinine excretion, and creatinine-height index [CHI] ).
d. Weight: 10.66 1.14 kg (range: 8.82 to 11.96). Height: 79.8 4.9 cm (range: 72.9 to 86.4). Weight-for-height, percentage of expected: 98 1 per cent (range: 96 to 100 per cent). CHI: 0.95 0.07 (range: 0.89 to 1.04).
e. Intestinal parasites: Two children had asymptomatic giardiasis. One of them also had a light infestation with Trichuris trichiura (one or two eggs per microscopic slide preparation). They were not treated before the study.
f. All children were healthy throughout the study.

2. Study Environment
INCAP's Clinical Centre in Guatemala City, 1,500 m above sea level. Temperature: 18 to 24 C. Relative humidity: 40 to 50 per cent.

3. Physical Activity
Since no child had diarrhoea and defecation habits were known by the nurses, the children were confined to metabolic beds only part of the day. During most of the day they moved freely in the Clinical Centre and outdoor playing grounds wearing urine-collection bags, except for those children who were toilet-trained. They participated in games that involved climbing ramps, walking uphill, and tossing balls.

4. Duration of the Study
Four children were studied simultaneously for nine days. A fifth child was studied five months later for seven days.

5. Diet

  1. A nitrogen-free, liquid formula was prepared with the following ingredients (g/kg/day): cornstarch 2.5; sugar 15.2; cottonseed oil 3.3; mineral mixture (NaCI, KCI, Na2HPO4, CaCO3, mg SO4) 0.6; water to make a final weight of 80 g/kg/day.
  2. The liquid formulas were cooked for 10 to 20 minutes. They were free of fibre, and vegetable oil provided 30 per cent of the energy.
  3. The diet, which provided 100 kcal/kg/day, was divided into five isoenergetic meals and fed at threehour intervals. It was supplemented with vitamins, iron, iodine, zinc, and manganese. Additional water was offered ad libitum.
  4. Prior to the study, the children consumed milk-based liquid formulas for several days.

6. Indicators and Measurements

  1. Urine was collected at 23- to 25-hour intervals, and the volume was corrected mathematically to correspond to a 24-hour period. Faeces were not collected during the first day of the study. Beginning on the second day, carmine red and brilliant blue were given alternately as markers with breakfast every two days. Faeces were collected between markers as 48-hour pools. They were dried at 80 C and homogenized.
  2. Urinary and faecal aliquots were digested, and their nitrogen contents were determined by a microKjeldahl technique using selenium (Se) as a catalyst. Diet aliquots were analysed in the same way to ensure the absence of nitrogen. Tryptophan standards were analysed simultaneously.
  3. Body weight was measured daily before breakfast.