This intestinal flora study was a part of the Akakura Study, which was carried out to determine the cadmium (Cd) absorption rate from ordinary diets in humans by comparing Cd content in the diet with that in the feces and urine. This report describes the composition and changes of intestinal bacterial flora among young Japanese females living together in the same dormitory and eating the same Cd-controlled diets. Subjects consumed the same menus designed by a dietician for two weeks. Before and after the study, subjects completed a profile of mood states (POMS) questionnaire to ascertain stress levels. Fecal samples were collected and the flora analyzed at three points during the study. The mean wet and dry weights of feces per day were 98.6 g (74.2-136.7) and 21.0 g (16.3-25.4), respectively. The total number of bacteria did not change significantly during the study period.
Bacteroidaceae, Eubacterium, Bifidobacterium, Enterobacteriaceae, Streptococcus and
Lactobacillus were recovered from all subjects, while
Bacillus and
Peptococcaceae were obtained from about half of them. The major components were
Bacteroidaceae, Eubacterium, and
Bifidobacterium. The next common species were Enterobacteriaceae,
Streptococcus, and
Peptococcaceae,
Lactobacillus, and
Clostridium other than
C. perfringens. C. perfringens, yeast and
Megasphaera were present rarely or occasionally. As a stress level, mean POMS fatigue and depression scores were unchanged throughout the study, the vigor score increased and the tension-anxiety score decreased compared to those before starting the study. There were no significant differences in the composition of fecal flora among individual subjects. The total number of bacteria tended to decrease over time, but the change was not statistically significant. The proportions of
Bifidobacterium and
Bacteroidaceae tended to increase.
Lactobacillus also tended to decrease in all participants, and it was not related to the removal of milk and yogurt from the diet. It is not clear what part of the diet caused these differences.
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