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close this bookProtein-Energy Requirements of Developing Countries: Evaluation of New Data (UNU, 1981, 268 p.)
close this folderNitrogen absorption-adults
close this folderAbsorptive capacity of adult Guatemalan rural males living under different conditions of sanitation
View the document(introduction...)
View the documentObjectives
View the documentExperimental details
View the documentSummary of main results
View the documentConclusions


The results indicate that adult men from rural areas of a developing country who live under conditions of poor sanitation, without appropriate use of potable water, and who eat diets largely based on corn and black beans with some animal protein and low fat (about 11 per cent of total energy intake) have apparent absorptions of the order of 90 per cent of total energy, 75 to 80 per cent of protein, and 75 to 85 per cent of fat. It is also evident that these men's absorptive capacity improves after they have lived for two years in environments with better sanitation and have modified their hygiene habits through education. Their apparent absorptions become about 93 per cent of total energy, 85 per cent of protein, and 90 per cent of fat.

If we assume faecal obligatory losses of 12 to 14 mg N/kg/day, the "true" nitrogen digestibilities would be about 5 per cent higher than apparent digestibilities.

The diets used in this study were typical of the region, although their protein content (P% about 13.6 ) and the contribution made by protein of animal origin (about 34 per cent of total protein) were higher than those in the diets of most men of similar ethnic, cultural, and socioeconomic conditions in other parts of the country. It is conceivable that protein absorption may be somewhat lower in the latter, whose diets have a P% closer to 10 than 13, with animal proteins contributing only 20 to 25 per cent to the total.

The results obtained also indicate that future research studies involving measurements of absorptive capacity in rural subjects should allow about five days of dietary adaptation before starting the metabolic-balance studies.


These studies were done as part of a project carried out jointly by the University of North Carolina and INCAP with the economic support of the US Agency for International Development. The United Nations University contributed support for the last stages of data analysis.