458 THIAMINE 



It is a remarkable fact that the meat of pigs is very rich in thiamine. 

 Pork is one of the richest sources of thiamine. Lean pork contains nearly 

 1 mg. of thiamine per 100 g. Fish on the whole contains somewhat less 

 thiamine than beef, but the difference is not very large. In eggs, most of 

 the thiamine is in the yolk ; the thiamine content of fresh yolk is about 300 

 7 per 100 g. 



/. Milk 



Taking into account the fact that the amount of dry matter in fresh 

 cow's milk is only 13 %, the thiamine content, about 45 j per 100 g., is 

 fairly good. Human milk contains only one-third as much thiamine as 

 cow's milk. Part of the thiamine in human milk is in the form of pyro- 

 phosphate and of orthophosphate.'" 



Kon (in Reading, England) estimated the influence of pasteurization and 

 sterilization on cow's milk that is used for feeding infants. Pasteurization 

 of the milk reduces the thiamine content about 10 %, and the more drastic 

 sterilization procedures may destroy 30% or more." If we compare the 

 content of this sterilized milk with the recommendation of the Food and 

 Nutrition Board of the American National Research Council for infants, 

 we see that the margin of safety for thiamine in the sterilized milk used 

 as an infant food is small. On the other hand, in breast milk the thiamine 

 content is still lower. Holt et al.,^^ who themselves estimated the thiamine 

 requirement of infants, draw attention to this fact. They suppose that 

 perhaps in infants fed with breast milk part of the required thiamine is 

 synthesized by the microflora in the gut. 



Fortunately most infant foods are acidified (by churning or by the addi- 

 tion of an acid), and in these preparations the thiamine is much more stable. 



B. OCCURRENCE OF NATURAL ANTITHIAMINES 

 AND THIAMINASES IN FOODS 



Not so much is known about natural antithiamines in food. There is 

 quite a literature, however, on thiaminases. The first indications of a harm- 

 ful influence from the consumption of fresh-water fish were found on a 

 silver fox farm of a Mr. Chastek. These foxes developed a paralj'^sis that 

 was afterward called the Chastek paralysis. Green et al}^' ^* demonstrated 

 that this disease arises in foxes on a diet containing 10 % or more of fresh 



1" S. de Jong, Enzymologia 10, 253 (1942). 



'1 S. K. Kon, Brit. Med. Bull. 5, 170 (1947). 



'2 L. Emmett Holt, Jr., R. L. Nemir, S. E. Snyderman, A. A. Alhanese, K. C. Ketron, 



L. P. Guy, and R. Carretero, J. Nutrition 37, 53 (1949). 

 " R. G. Green, W. E. Carlson, and C. A. Evans, /. Nutrition 21, 243 (1941). 

 " R. G. Green, W. E. Carlson, and C. A. Evans, /. Nutrition 23, 165 (1942). 



