Recent Advances in Nutrition and Metabolism

Abstract

depending in some cases upon the method and in others upon the definition of lean body mass. For example, quite different results are obtained if the fat in the parenchymal cells is considered a part of lean body mass rather than included with fat depots. This and other problems remain to be worked out. NUTRITION, AGING, AND CHRONIC DISEASEThe separation of the process of senescence from the chronic diseases which so often occur in old age, such as diabetes, diseases of the heart and arteries, cancer, and the arthritides, is indeed difficult and has attracted some attention. § It is now common knowledge that many of these "degenerative diseases" are related to dis¬ turbances of nutrition, and, in fact, they may be prevented in some instances and treated in others by special nutritional means. To what extent senescence itself may be altered or its onset delayed by careful attention to nutrition is quite unknown, but the problem is being attacked.As one would expect, there is a definite increase in fat content of the body with age. This is particularly noticeable in women. The increase in fat is not simply additive but is associated with a decline in muscle mass. This was true of a group of middle-aged white-collar workers studied by Brozek.16 Two groups of these persons were selected. Those in the first group were accustomed to regular physical exercise, whereas the others had always led a more sedentary existence. They were matched for age and height. It was found that the active persons were heavier than those of the sedentary group, but the excess weight was due to an increase in lean body mass and not to fat. This suggests that the decline in lean body mass with advancing years is to some extent "disuse atrophy." Some hope is thus offered for the prevention of the loss of muscle tissue in the aged.A number of recent books concerned with aging have appeared. An excellent study of nearly 8,000 persons over 61 years of age has been published by Monroe,21 which emphasizes medical complications, including nutritional disturb¬ ances. Stieglitz, Portis, and King | | examined 133 persons between the ages of 60 and 83, with particular respect to nutrition and the gastrointestinal tract. Included in their studies were not only the usual history and physical examination but also hématologie studies, gastric analysis, dextrose-tolerance tests, electrocardiograms, basal metabolic rates, and roentgen examinations of the gastrointestinal tract. A discussion of the psychological aspects of aging and the treatment, including the diet therapy, psychotherapy, and general medical management is given. The diffi-\ s=s\ References 14 and 15. \ m=par \ References 22 and 23.