One paper, presented by Molla (paper 29), was specifically designed to deal with the effect of infections on protein energy requirements of children in Bangladesh. This study examined, in a hospital setting, the food intake and nitrogen balance in children with diarrheal disease of different etiologies (cholera, rotavirus, pathogenic Escherichia coli (ETEC), and Shigella). Energy absorption during the acute state of the disease was 81, 55, 88, and 68 percent of intake, respectively. Nitrogen absoprtion dropped to 42, 45, 58, and 41 percent, depending on the etiology of the diarrhea. Children were allowed to eat as much as they wanted of their customary diet and were accompanied by their mothers or family. Food intake dropped to 70 percent of recommended levels during the first week of diarrheal disease. Absorption of nitrogen and fat ranged from 40 to 80 percent; carbohydrate absorption was least affected.
Follow-up studies performed two weeks later showed that most patients had increased food intake to meet or exceed current recommendations, and intestinal absorption had become normal. However, children affected with rotavirus diarrhea continued to show impaired nitrogen absorption for up to 8 weeks after the acute episode.
Nitrogen balance studies showed that with continued unrestricted food intake 52 percent of the patients with cholera, 25 percent with diarrhea due to rotavirus, 54 percent with ETEC, and 33 percent with Shigella were in positive balance.
In the long-term study by Torun (paper 23), several children suffered 12 episodes of mild infections, during which a tendency to decrease food intake was observed together with increase in urinary nitrogen excretion, weight loss, or a decrease in rate of weight gain.
A study by Espinoza et al. (paper 30) explored the effect of fiber on nutrient digestibility. Subjects were fed 0.8 g of egg protein with either 6 or 20 g of structured fiber. Significant increases occurred in stool weight, nitrogen, and fat content with a concomitant decline in urinary N that compensated so that N balance was maintained.
It would be important to differentiate whether faecal nitrogen increased because of an alteration in absoprtion of ingested nitrogen, or to an alteration in colonic flora producing an increased loss of endogenous nitrogen, or a combination of the two. The study also included measurements of fiber constituents. Digestibility of fiber was 37 percent and 56 percent at low and high fiber intake, respectively.
Bressani (paper 31) reported data on the effect of the polyphenol content of beans on protein digestibility. There was a significant increase in faecal N loss when polyphenols were added to the diet.
Additional data on obligatory N losses in village and college men were reported by Atinmo from Nigeria (paper 32). Mean daily urinary N loss after stabilization was 43.5 and 43.9 mg N/kg for college and village subjects, respectively. These values are slightly higher than those reported by Uauy et al. (12) or the ones used by the FAO/WHO 1973 report. However, mean daily faecal nitrogen was 21.8 in the village men and 18.3 mg N/kg for the college students. These values are much higher than the 12 mg N used by the FAO/WHO 1971 expert committee, which was derived from studies in developed countries. The diet given in these studies was based on local foods that contained minor amounts of animal protein totalling 15 mg N/kg/day, rather than the refined food traditionally used in these types of studies that provide less than 2 mg N/kg.
Scrimshaw described the work of Vysotsky (paper 33) of the USSR that yielded valuable comparative information on obligatory N losses. Urinary N loss while consuming a protein-free diet was 2.5 g/day, which is similar to other reported data.
Rand and Zacharias (paper 34) presented prospective data on the adolescent growth of 338 healthy girls of Newton, Mass., U.S.A. Height measurements were taken monthly, and velocities estimated from a fitting of the data expressed as gain per year starting at 6 years of age and ending at 18 years. These results show the variability of prepubertal linear growth as well as of that observed during the growth spurt. Adolescent linear growth also varies significantly among individuals in relation to a specific age in which peak velocity is reached. For example, at age 15 the 25th percentile of the linear growth velocity is 0.3 cm/year, the median is 0.8 cm/year, the 75th percentile is 1.6, and the 95th percentile is 4.2 cm/year. Thus, variability in height gain in normal adolescent populations may be up to 5 times the median value. The implication of growth rate variability in defining protein-energy requirements was discussed.
A paper on protein energy needs during the acute stage of recovery from malnutrition in infants by del Rio et al. presented and discussed in the M.I.T. 1980 meeting is included in this publication (paper 35). This research found that recovery from serious protein-calorie malnutrition, as judged by weight of arm, was more rapid in infants receiving 17% protein calories than in those receiving 11% protein calories.
