Related Experiment Videos
Volunteers who are able to donate blood frequently without becoming anemic provide a unique opportunity to observe iron balance under conditions of controlled blood loss. The 88 men and 88 women studied had given a mean of 17 donations (range 10-24) over 4 years. Twenty-seven percent of men and 45 percent of women took iron-containing supplements. In these "superdonors," estimated iron loss averaged 3.8 mg/day in men, 3.4 mg/day in menstruating women and 3.0 mg/day in nonmenstruating women. Dietary iron consumption estimated from the dietary history averaged 17 mg/day for men and 13 mg/day for women; in general, the superdonors consumed a superior diet. Sixty-three percent of the unsupplemented individuals had ferritin values less than 20 micrograms/l. Assuming that stores were constant, these individuals would have to absorb 25 percent of their dietary iron to meet total iron loss. Supplemented men and women taking an average of 24 and 34 mg of additional iron per day, respectively, showed relatively little difference in iron balance from unsupplemented individuals; 58 percent had serum ferritin values of less than 20 micrograms/l, and 28 percent were equal to or less than 12 micrograms/l. The low level of absorption (6-9%) in supplemented individuals suggests that the iron availability of iron-containing preparations ingested may have been poor.
Volunteers who are able to donate blood frequently without becoming anemic provide a unique opportunity to observe iron balance under conditions of controlled blood loss. The 88 men and 88 women studied had given a mean of 17 donations (range 10-24) over 4 years. Twenty-seven percent of men and 45 percent of women took iron-containing supplements. In these "superdonors," estimated iron loss averaged 3.8 mg/day in men, 3.4 mg/day in menstruating women and 3.0 mg/day in nonmenstruating women. Dietary iron consumption estimated from the dietary history averaged 17 mg/day for men and 13 mg/day for women; in general, the superdonors consumed a superior diet. Sixty-three percent of the unsupplemented individuals had ferritin values less than 20 micrograms/l. Assuming that stores were constant, these individuals would have to absorb 25 percent of their dietary iron to meet total iron loss. Supplemented men and women taking an average of 24 and 34 mg of additional iron per day, respectively, showed relatively little difference in iron balance from unsupplemented individuals; 58 percent had serum ferritin values of less than 20 micrograms/l, and 28 percent were equal to or less than 12 micrograms/l. The low level of absorption (6-9%) in supplemented individuals suggests that the iron availability of iron-containing preparations ingested may have been poor.