It is difficult to know at the present time how near to the actual intake an estimate of the vitamin B1 content of any diet is likely to be, owing to the natural variability in the chemical composition of food materials (which is known to be very wide in case of the vitamins), the comparatively small numbers of assays of vitamin B1 that have been done under identical conditions on any given food and the large number of foods for which quantitative data are lacking. Furthermore, there is increasing evidence that the loss of this vitamin in the preparation of food may be great. Munsell and Kifer 1 found a 50 per cent loss in cooking broccoli; Funnell,2 a 25 per cent loss in cooking green peas only fifteen minutes, and Rose, Vahlteich, Funnell and MacLeod,3 a 40 per cent loss in the steaming and toasting of bran to make a product for human consumption. It seemed to us of interest, therefore, to study the vitamin B1 intake of some nursery school children by an assay of composite samples of the food taken by each child.Four boys ranging in age from 40 to 55 months were selected because they were good examples of normal nursery school children and because their mothers were willing to cooperate in the collection of weighed duplicates of every item eaten for five consecutive days.One of us supervised the collection of these duplicate samples in the nursery school at noon and also went to the homes and collected the weighed samples there. If any food was eaten between meals a duplicate of this was also kept by the mother.
