The effect of three dietary fibers on zinc, copper, and magnesium utilization by adolescent boys was studied. The 21-day study was divided into a 2-day introductory nitrogen depletion period, a 3-day adjustment period, and a four 4-day randomly arranged experimental period. During the four experimental periods, the eight adolescent male subjects received a basal diet plus 14.2 g supplements of cellulose, hemicellulose, or pectin. All subjects received all experimental diets. Zinc, copper, and magnesium contents of food, urine and blood serum were measured by atomic absorption spectrophotometry. Relatively small changes in urinary excretion or in blood serum contents of these minerals were found that could be attributed to dietary fiber supplementation. Statistically significant changes in fecal mineral loss were demonstrated. While receiving the basal diet alone or plus hemicellulose, cellulose, or pectin, mean fecal zinc contents (milligrams per subject per day) were 9.64, 13.32, 10.26, and 9.63, respectively; mean fecal copper contents (milligrams per subject per day) were 3.78, 5.04, 4.07, and 3.91, respectively; and mean fecal magnesium contents (milligrams per subject per day) were 303.71, 379.20, 325.69, and 278.48, respectively.

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The objective was to determine the effect of cellulose supplementation of a nutritionally complete, liquid formula diet on fecal fiber composition, cellulose digestion, and gastrointestinal tract motility in healthy human adults. The liquid formula product was supplemented with 0, 20, 30 or 40g cellulose/subject/day. Dry fecal weights increased with increasing levels of cellulose; however, moisture content of wet stools tended to decrease. Approximately 76% of the cellulose supplements were recovered in the stools as cellulose. While fecal transit times tended to decrease and number of defecations per period tended to increase with increasing levels of cellulose,. stools at high levels of cellulose were abnormal in appearance and several subjects experienced problems with elimination.

The objective of the study was to determine the effects of green tea, black tea and decaffeinated black tea consumption on urinary and fecal excretions and whole blood and blood serum concentrations of polyphenols. The 56 day study was divided into four randomly arranged experimental periods of 14 days each during which the 10 healthy adult subjects consumed a laboratory controlled, constant, measured diet based on ordinary foods. During separate periods, subjects received no tea, green tea, regular black tea or decaffeinated black tea beverages at the three daily meals. Subjects made complete collections of urine and stools throughout the study and fasting blood samples were drawn at the beginning of the study and at the end of each experimental period. Polyphenols contained in urine, feces, whole blood, blood serums, food and tea were analyzed by the spectrophotometry method of Wah Lau et al. (1989). Green tea consumption resulted in highest intakes in greatest fecal and urinary excretions, highest retentions, and high whole blood concentrations of polyphenols followed by effects of regular black tea, decaffeinated black tea and no tea treatments. These results indicate that polyphenols from tea are at least partly absorbable. Hence, both positive and negative effects of dietary polyphenol may occur internal to the body proper and not only as effects within the intestines.

Total sulfur-containing amino acids have been found to be the first limiting amino acid in several foods in comparison with human amino acid requirements. Addition of methionine in appropriate amounts to these foods might be expected to improve protein value. Economically, DL-methionine would be preferable to L-methionine for this purpose. However, the comparative tuilization of L- DL-, and D-methionine is unclear. The objective of the current project was to compare the effectiveness of L-, DL-, and D-methionine supplementation of diets based on a food product known to be low in methionine value for human subjects. "Instant" oatmeal was fed to adult subjects to provide 4.0 g of nitrogen/day. In randomly arranged periods, these diets were supplemented with L-, DL-, or D-methionine at two levels (0.58 and 1.16 g of methionine/day). An unsupplemented diet was used in a control period. Diets were adequate in vitamins, minerals, and energy. Mean nitrogen balances of subjects while receiving the L-methionine supplements at the 0.58 and 1.16 g levels were minus0.10 and +0.06 g of nitrogen, respectively. At similar levels of DL-methionine supplementation, nitrogen balances were minus0.12 and minus0.15 g of nitrogen, respectively, and minus0.24 and minus0.18 g of nitrogen with D-methionine supplementation. The mean nitrogen balance when no supplement was used was minus0.22 g of nitrogen. Thus, D-methionine is seemingly poorly utilized by the human. Urinary methionine excretion data supported these results.