IMPORTANCE OF BALANCED DIET 



83 



rays. Caution should be used in the purchase and use 

 of the so-called sun lamps, as there are many fraudu- 

 lent products of this sort on the market. 



In the use of any sun lamp it is necessary to use 

 great precaution. While ultra-violet rays have been 

 found to be very beneficial, over exposure to them can 

 be very harmful by causing severe and dangerous 

 burns and by reducing the power of the body to fight 

 off bacterial infections. 



Vitamin B prevents the disease beri-beri. This vita- 

 min is found in a great many of our common vege- 

 tables, such as cabbage, tomatoes, and spinach. It is 

 also abundant in fresh yeast and milk. 



Beri-beri is a disease of the nervous system in which 

 the nerves become inflamed. It may result in the rigid- 

 ity of the muscles. 



Exercise. Health authorities sent to the Philippine 

 Islands following the Spanish-American War found 

 many people ill of beri-beri. An investigation revealed 

 that the diet of many of these people consisted of white 

 or polished rice from which the outside hulls had been 

 removed. It was further found that when these people 

 were fed with rice which contained the outside hulls the 

 victims improved almost at once. 



Exploring expeditions to the Arctic and Antarctic 

 regions in years past have almost always had men af- 

 flicted with beri-beri. Their diets were, for the most part, 

 made up from tinned foods and contained no fresh fruits 

 or vegetables. In his two trips to the Antarctic Admiral 

 Byrd did not hare a single man ill of beri-beri. Their 

 diet was supplied with litamins. What inference can one 



draw from the data presented by these two examples? 

 In your notebook 1 record your inferences. 



Vitamin C prevents a skin disease known as scurvy. 

 Have you ever known any person who had this dis- 

 ease? Probably not, because vitamin C is abundant 

 in green vegetables and fruits which are found in the 

 average American diet. Vitamin C is destroyed by 

 prolonged cooking. 



Milk which has been boiled or pasteurized contains 

 less of vitamin C, and therefore children fed on milk 

 that has been thus treated must have some substance 

 such as orange juice or tomato juice to supply the 

 needed vitamin. If the proper food is not provided 

 these children may develop scurvy. 



Vitamin E prevents sterility. Animals fed on diets 

 lacking vitamin E fail to produce young. It is present 

 in vegetables and especially abundant in grains. 



How should we select our food? The amount and 

 kinds of food a person should eat depend upon a 

 number of factors. An individual's activity must be 

 considered. When we indulge in strenuous physical 

 exercise or do hard manual labor, cells in the muscle 

 are used up. We need to eat foods that will build up 

 and repair cells, and for this purpose we need protein 

 foods. Substances containing carbon, oxygen, hydro- 

 gen, and nitrogen must be present in the body so that 

 new cells can be made. If you refer to the section on 

 nutrients (page 81) you will recall that proteins are 



'See workbook, p. 31. 



FOODS RICH IN VITAMINS 



