Abstract
Constituents of beri-beri-producing diets, borderline diets, and protective diets given by Braddon and others were analysed for vitamin B1 content by Cowgill. He used a long series of assays published by numerous investigators and calculated the various units and percentage values as milligram equivalents of a yeast powder. He thus obtained approximate vitamin B1 values for these diets. He showed that these values, together with the incidence of beri-beri, justified the application to man of a formula obtained experimentally and gave an indication of man's minimum requirement of the vitamin.
In this paper the vitamin B1 value of the same diets has been obtained from direct assays against the International Standard of the constituent foods, raw or cooked, as usually eaten. These are in good agreement with the values drawn from the less direct calculation, and indicate that man's minimum requirement may vary according to weight and food intake between 200 and 500 units daily.
The desirable level of B1 intake for adults and children has been studied by analysing in the same way a series of diets recommended by public bodies or by dietitians in England and America. Adults on good diets consume 450 to 750 units daily. High vitamin diets may contain about 1,500 units.
Diets recommended for children show relatively higher levels than those for adults, that of a child aged 4 years having nearly 400 units and that of a child aged 11 years having about 650.