Erythrocyte survival time and reticulocyte levels after tocopherol depletion in man.

T HIS report, which will present only a small part of the data obtained during a current long-term study’ of the human requirement for tocopherol, will attempt to demonstrate alterations in human blood that are similar to those reported by Dinning and Day4 and Maryin et al.5 in monkeys. It will show, in support of vIarvin’s study6 on a series of animals, that in the study of the survival time of erythrocytes, it is more useful to observe 90 or 95 per cent Cr5’ survival times than the Cr5’ ‘ ‘half-life’ ‘ when the differences expected are small. The general complexity of the tocopherolpolyunsaturated fatty acid relationships should be reviewed briefly in order to set the stage for the discussion on blood components to follow. It is becoming increasingly apparent that if the diet of a growing animal is kept reasonably low in polyunsaturated fats, and if other lipid antioxidants are provided, the amounts of tocopherol needed during the early stages of life can be so small that none can be detected in the tissues even with our best methods of tocopherol analyses.79 Nevertheless, assuming that some does escape our analytic procedures, the amount is so small that we can agree that if tocopherol is needed for an enzymatic process, the amount is of an order far less than that found in our experimental