Manganese Metabolism in College Women

Abstract

Manganese metabolism was studied in 9 healthy college women ranging in age from 18 to 21 years. A basal diet supplied subjects with adequate amounts of all essential nutrients. To provide additional food energy for those subjects whose requirements exceeded the amount included in the basal diet, certain foods were allowed ad libitum, and a record kept of their consumption. The study consisted of eight 5-day periods, with one post-experimental day, making a total of 41 days. Composites of the basal diet and of the fecal and urine specimens for each 5-day period were analyzed for manganese. The ad libitum foods also were sampled and analyzed. The results of the analyses showed that the basal diet provided a mean daily intake of 3.16 mg of manganese with some variation from period to period. The manganese intake for the 9 subjects, (basal diet plus ad libitum foods) was 3.70 mg per day. The results of the analyses of the urine and fecal specimens gave a mean daily manganese excretion for all subjects of 2.17 mg, of which 91% was in the feces. The mean daily retention of the subjects was 1.54 mg or 41% of the intake. Manganese intakes and retentions also were computed for the subjects on the basis of body weight. The mean daily intake was 0.068 mg per kg (range, 0.049 to 0.084 mg) and the mean retention, 0.028 mg per kg (range, 0.023 to 0.035 mg). For these subjects manganese retention was significantly related to intake, based on the data for the 5-day periods. The regression coefficient also was computed on these data. A linear relationship between intake and retention was observed. It is possible that intake levels higher than those used in this study would have resulted in greater retentions.