COOKING AND VITAMINES 



By ELLEN MARION DELF, D.Sc. (Lond.). F.L.S. 



Late J arrow Research Fellow Girton College ; Temporary Research Assistant 

 at Lister Institute, and Resident Lecturer in Botany. Westfield College, 

 University, London. 



I. Introductory. — Cooking is an art of great antiquity. In 

 the not distant future it may well become also a science. 

 The recognised objects of cooking are to improve the digesti- 

 bility and palatability without at the same time impairing 

 the food value of the substance. To this may also be added 

 that cooking often destroys bacteria and other organisms, 

 and thus lessens the danger of harmful effects in this direction. 



Until recent years it has been the custom to estimate the 

 food value of an article chiefly by its chemical nature (whether 

 protein, carbohydrate, or fatty), and also by the digestibility. 

 Thus, bacon fat, or lard, is thought to be of great value because 

 as much as 90 per cent, of the intake can be absorbed. It is 

 now known, however, that other considerations are involved, 

 one of the most important being the presence or absence of what 

 have been called accessory food factors, or vitamines. At 

 present, the biological value of a food can be determined only 

 by the assistance of experiments on subjects kept on con- 

 trolled diets. Such experiments appear to be essential to the 

 understanding of food and dietary problems. 



Vitamines are substances which are present in nearly every 

 natural foodstuff, and they are necessary, in smaller or greater 

 amount, to the growth of the young animal as well as to the 

 maintenance of health in the adult. The absolute amounts 

 required by man are not determined, but probably do not 

 differ much from those of the monkey, which, in turn, have 

 been compared with those of the guinea-pig,^ so that experi- 

 mental results with either of these animals can be used with 

 more or less accuracy in the case of man. 



Three accessory food factors, or vitamines, are at present 

 well known. These are widely distributed in natural foods, 

 and a sufficiently varied diet of food, which is not overcooked, 

 is unlikely to be deficient in any of them. Two are especially 

 concerned with growth, and have been called respectively 

 fat-soluble A and water-soluble B. In the entire absence of 

 either of these normal growth ceases. Certain diseases are 

 definitely associated with a deficiency in the diet of these 

 vitamines, especially rickets in the case of the fat-soluble, and 



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