Thiamine requirement of rats given a high-protein, carbohydrate-free diet

Although much light has been shed on the biochemical aspects of thiamine deficiency, the relationship between the requirement for this vitamin and the level of dietary carbohydrate remains obscure. Banerji (1941) and Banerji & Yudkin (1942) found that characteristic signs of thiamine deficiency such as convulsions did not appear in rats fed on a carbohydrate-free, high-protein diet, though other signs, such as increased excretion of bisulphite-binding substances and the ' catatorulin effect' (Gavrilescu & Peters, 1931 b ; Peters, 1936), persisted. On the basis of their results Banerji (1941) and Banerji & Yudkin (1942) suggested that, though thiamine-deficient tissues showed defective carbohydrate metabolism, convulsions (as a sign of deficiency) only appeared when carbohydrate was included in the diet, and were due to accumulation of some unknown toxic product of perverted carbohydrate metabolism. It was only when these workers (Banerji, 1940; Banerji & Yudkin, 1942) used high-fat diets that their animals thrived well, owing to the wellknown thiamine-sparing action of fat. Recently Morgan & Yudkin (1957) have put forward the view that carbohydrate might be considered as a toxic substance, whose antidote is thiamine. In view of these interesting suggestions of Yudkin and co-workers, the experiment of feeding rats on a high-protein diet in the absence of thiamine was repeated, particular attention being paid to the appearance of nervous signs of deficiency. The effects of a high-protein, carbohydrate-free diet are reported here and the pharmacological responses of thiamine-deficient tissues are reported elsewhere (Boullin, 1960).