Nutrition in the exercising elderly.

During the past two decades, an enormous increase has occurred in the number of older individuals engaged in regular exercise and recreational and competitive athletics. A large percentage of these individuals are participating in exercise for the benefits that fitness has on decreasing all-cause mortality and increasing physiologic functioning, whereas others are competing in senior and masters-level events and are focused on performance. 11 , 103 With this growing number of older individuals participating in regular exercise and athletic competition, the nutritional requirements of this population need to be appropriately addressed. Recommendations for nutrition in older athletes should focus on both the nutrient requirements for increasing age and the nutrient needs for exercising. Many physiologic changes occur with age that affect an individual's nutritional need. First, decreased appetite and food intake are affected by a decreased sensitivity to taste and smell, poor dental health, and a lost sense of thirst. The gastrointestinal tract functions less efficiently because of decreases in acidity, reduced production of specific digestive factors and enzymes, and delayed gastric emptying time. The liver, gall bladder, and immune system may also function less efficiently. Low-fat, low-cholesterol, and low-sodium diets are recommended for those with cardiovascular health problems. Functionally, a loss of bone density, lean tissue, and type II muscle fibers and an increase in fat and collagen within the muscle tissue occur. Finally, approximately 85% of the elderly population suffers from some type of chronic degenerative disease, and potential drug-nutrient interactions may affect the digestion, absorption, and utilization of several nutrients. 61 With respect to the nutrient requirements that accompany these age-related changes, recommended dietary allowances (RDAs) are given to define “the level of intake of essential nutrients that, on the basis of scientific knowledge, are judged by the Food and Nutrition Board to be adequate to meet the known nutrient needs of practically all healthy persons” 95 ; however, the data used to determine the RDAs often did not include athletes or regularly exercising individuals in their studies, or the exercise status of the subjects was not reported. Furthermore, the oldest age group for which many recommendations are given is over 51 years. This is a very broad age range during which several metabolic and physiologic changes occur that require different nutrient needs. Only recently have new RDAs been reported for 51 to 70 years and, for several nutrients, greater than 70 years. 57a , 152a Thus, the RDAs may not be an accurate means of evaluating the nutritional needs of older athletes. The new RDAs include current concepts about the role of nutrients in long-term health, but again, these values have not been set for all nutrients. 57a , 152a Finally, recommendations need to encompass aspects of nutrition that affect athletic performance on a day-to-day basis. This article reviews the present knowledge of each of the macronutrients and micronutrients that are affected by aging and exercise (Table 1) .