XII. REQUIREMENTS AND FACTORS INFLUENCING THEM 479 



Foltz ct a/.,^' using tour nietlical students under observation in a hospital, 

 found that a daily intake of 0.2 nig. i)er 1000 eal. resulted in deheieney 

 symptoms within 8 weeks. It is their opinion that the minimum daily 

 requirement of thiamine for young adult men is from 0.33 to 0.45 mg. per 

 1000 cal. 



Keys cl a/.^-' in further studies on men with restricted intake of the 13 

 vitamins found that an intake of 0.185 mg. of thiamine per 1000 cal. (daily 

 intake 3300 cal.) was slightly less than entirely adequate. 



Glickman et al.^^ found a daily intake of 0.4 mg. per 1000 cal. entirely 

 adequate. 



In an attempt to resolve some of the differences of opinion concerning 

 the minimum human requirement for thiamine, a study was conducted by 

 Horwitt et al.^'^ under the auspices of the National Research Council. These 

 investigations showed that 0.4 mg. of thiamine (0.18 mg. per 1000 cal.) was 

 below the minimal requirement of relatively inactive men on 2200 cal. 

 daily. 



On the basis of all the evidence available, therefore, the opinion of the 

 National Research Council^ that the minimal thiamine requirement for 

 adults is 0.23 mg. or more per 1000 cal. is well founded. On this basis and 

 in order to allow a suitable factor of safety for individual variation, differ- 

 ences in tj^pe of diet, and variations in body stores, which are never large 

 and easily depleted by various stresses, an intake of 0.5 mg. of thiamine 

 per 1000 cal. is recommended by the National Research Council as a safe 

 allowance for adults at ordinary low levels of calorie intake. 



The thiamine requirement of the infant on a calorie basis is similar to 

 that of the adult. Knott et al.^^ concluded that young infants have a mini- 

 mum thiamine requirement of approximately 0.2 mg. daily, which can just 

 be met if its mother's milk contains 20 7 or more of thiamine per 100 ml. 

 They suggest that 0.4 mg. of thiamine per kilogram may be a practical 

 standard for the ordinary needs of the young infant. The average thiamine 

 content of human milk was found to be about 0.15 mg. per liter. A more 

 critical analysis showed 0.2 mg. per liter in a group of women whose infants 

 were receiving no other milk in contrast to an average of 0.09 mg. per liter 

 in the milk of women whose infants required supplementary feeding. 



" E. E. Foltz, C. J. Barborka, and A. C. Ivy, GastroenteroUxjy 2, 323 (1944). 



" A. Keys, A. Henschel, H. L. Taj'lor, O. Mickelsen, and J. Brozek, Am. J. Fhi/siol. 



144, 5 (1945). 

 " N. Glickman, R. W. Keeton, H. H. Mitchell, and M. K. Fahnestock, Am. J. 



Physiol. 146, 538 (1946). 

 " M. K. Horwitt, E. Liebert, O. Kreisler, and P. Wittman, Bull. Natt. Research 



Council {U. S.), 116 (1948). 

 ^^ Recommended Dietary Allowances, Natl. Research Council {U. S.) Reprint and 



Circ. Ser. 129 (1948). 

 69 E. M. Knott, S. C. Kleiger, F. W. Scheutz, and G. Collins, J. Pediat. 22, 43 (1943). 



