IX. REQUIREMENTS AND FACTORS INFLUENCING THEM 573 



Ay prex'iously stated (p. 5-13), the average tlaily intake for atlult man 

 appears to be al)Oiit 14 to 19 mg. of (/-a-tocopherol. On the basis of tocoph- 

 erol analyses of foods it has been estimated^^ that on diets considered 

 low, average, and iiigh in vitamin E there would b(> ))i()\'idc(l, respccti\'ely, 

 1, 4, and 10 mg. of tv-toco[)herol for infants; 4, 10, and 20 mg. for children; 

 5, 15, and 35 mg. for adults; and 3, 10, and 15 mg. for aged persons. When 

 eonsidei'ation is given to losses due to storage, cooking, inactivation in the 

 gut, and fecal excretion, the latter representing l)y far tlie major loss, the 

 total available for metabolic utilization and storage might be reduced by 

 one-third more; this would give a net absorption of approximately 5 to 7 

 mg. of d-a-tocopherol dail}' for an average adult whose dail}' intake amounts 

 to about 20 mg. per day. The extent to which requirements vary with age 

 is not known. One might expect that, in terms of milligrams of tocoph- 

 erol per kilogram of body weight, the reciuirements during infancy and 

 childhood would be greater than during adult life. This would be in 

 keeping with the evidence of slow acquisition of body storage stores during 

 cliildhood and adolescence.^^' -^ It is not clear whether lowered tissue stor- 

 age observed in old age^^- ^^ represents diminished dietarj'^ intake or in- 

 creased needs to compensate for the generally lowered oxidative state of 

 bodj' tissues. On the experimental side, there is evidence of increased re- 

 quirements for reproductive function as age progresses. 



The requirements for vitamins are influenced by much the same condi- 

 tions which necessitate increased intake of vitamin A; namely, conditions 

 which chronicallj^ impair the absorption of fats from the gastrointestinal 

 tract. It seems reasonable to assume also that those factors which have 

 been shown to accentuate deficiency manifestations in animals, most of 

 which can be considered to represent types of metabolic stress (excess in- 

 take of unsaturated fats, low protein intake, ingestion of chemical sub- 

 stances such as o-cresyl phosphate or silver nitrate), can be regarded as 

 potentially capable of increasing human requirements as well. 



" K. C. D. Hickman, Record Chem. Prog. 9, 104 (1948). 



" K. E. Mason, M. Y. Dju, and L. J. Filer, Jr., Federation Proc. 11, 449 (1952). 

 , 2' K. E. Mason and M. Y. Dju, Nutrition Stjmp. Ser., National Vitamin Foundation, 

 New York!, 1 (1953). 



