MINERALS IN NUTRITION 23 



IV. THE EFFECT OF KELP AND MINERAL SUPPLEMENTS 



ON ATHEROSCLEROSIS IN RABBITS INDUCED 



BY FEEDING CHOLESTEROL 



By Helen S. Mitchell, Mildred F. Goldfaden, and Gertrude J. Hadro 

 Department of Home Economics Nutrition 



Nutritional problems of middle age, particularly those related to degen- 

 erative diseases, have received far less attention than those of infancy and 

 early childhood. The man or woman of fifty or sixty is faced with 

 thoughts of arthritis, hardening of the arteries, high blood pressure, can- 

 cer, or heart trouble — diseases for which there are no known cures, no 

 antitoxins, no specific remedies. If it could be shown that an excess or 

 a deficiency of one particular food component initiates or aggravates such 

 a disease, a program of prevention would be possible. If feeding experi- 

 ments with animals can furnish information in this direction, the science 

 of nutrition may come to assume as great importance in middle age as it 

 has for the childhood years. 



Atherosclerosis (hardening of the arteries) is a disease that alTects first 

 the large artery leading directly from the heart (called the aorta), and 

 later the smaller arteries of the body. In spite of numerous theories, its 

 cause is not known. Is it inevitable or preventable? The structure of 

 the arteries changes as they pass from the aorta into smaller branches. 

 In all these vessels there is a lining membrane composed of a single layer 

 of flattened cells which ofifers a smooth surface for the flow of blood and 

 protects the blood against contact with other body tissues. 



The earliest recognizable changes in the human aorta at the beginning 

 of the disease are slightly elevated flattened, yellowish streaks which may 

 develop throughout the entire aorta as the disease progresses. These 

 elevated patches stand out like solidified drops of paraffin. 



In the experimental form of atherosclerosis discussed in this paper, it 

 is evident that something besides aging is happening to the tissues to 

 cause the observed injury. There is interference with the normal func- 

 tioning of the walls, probably because the cells themselves are being in- 

 jured. The feeding of cholesterol or feeds containing cholesterol to rab- 

 bits has become an effective means of producing an atherosclerosis that 

 is very much like the human disease and that does not occur spontane- 

 ously in these animals. This condition is associated with an increase in 

 the cholesterol content of the blood and with a general accumulation of 

 fatty substance known as lipemia. In rabbits the arch of the aorta and the 

 areas around the opening of the arterial branches are the first sites of 

 injury. A progressive increase in the number and size of the lesions 

 follows. The spots appear as elevations of a white, grayish white, or yel- 

 lowish color. They vary greatly in size, the smallest looking like dots or 

 tiny streaks, while the larger ones range in size up to continuous streaks 

 of considerable magnitude. Sometimes there is calcification in the later 

 stages. 



Iodine has long been used in treating atherosclerosis, without exact 

 knowledge of its action. It has therefore been used in an attempt to 

 inhibit the occurrence or course of the experimental disease in animals. 



