Antithiamine factor

Thiamine status is influenced by the diet and by a variety of other factors, including its bioavailability in food products, ethanol consumption, the presence of antithiamine factors in the diet as well as folate and protein status. Ingested thiamine is fairly well absorbed, rapidly converted to phosphorylated forms, stored poorly, and excreted in the urine in a variety of hydrolyzed and oxidized products (TanPhaichitr et al., 1999). 

ANTITHIAMIN FACTORS IN FOOD. Certain raw fish and seafood—particularly carp, herring, clams, and shrimp— contain the enzyme thiaminase, which inactivates the thiamin molecule by splitting it into two parts. This effect has been seen in mink and fox fed 10 to 25% levels of certain raw fish, giving rise to a thiamin deficiency disease known as Chastek paralysis. This action can be prevented by cooking the fish prior to feeding, thereby destroying the thiaminase. Of course, humans seldom eat sufficient thiaminase-contain-ing raw fish or seafood to produce a thiamin deficiency. 

Fukuoka, M. Chemical and Toxicological Studies on Bracken Fern, Pteridium aqui-linum var. latiusculum. VI. Isolation of 5-0-Caffeoylshikimic Acid as an Antithiamine Factor. Chem. Pharm. Bull. (Japan) 30, 3219 (1982). 

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