Geriatric nutrition.

The aging process alters body composition so that nutritional status changes as we get older. The aging process shows interindividual variability in its rate of development. Determinants of the rates of aging of systems and tissues are largely genetic. Premature aging of cells and tissues is due to genetic factors and to long-term exposure to physical or chemical environments that cause irreversible tissue damage. Whereas maximal lifespan is fixed for us all, individuals vary in life expectancy both because of variability in the risk of genetic disease which shortens life and because of variable capability for avoidance of those factors in our environment which cause early aging. Early aging as well as geriatric disease foreshorten life, but both can be prevented to some extent by diet or by diet and exercise. Diseases that can be nutritionally prevented, giving us a greater chance of achieving our genetically determined lifespans, include nutritional deficiency states and chronic diet-related diseases such as non-insulin-dependent diabetes, hypertension, coronary artery disease, and cancer. Disabilities resulting from these diseases and from degenerative arthritis are also subject to modulation by diet. The nutritional requirements of the elderly are mostly similar to those of younger people. Elderly usually need fewer calories and similar nutrient intakes compared with those of younger people. Elderly with higher needs for specific nutrients include homebound or institutionalized people who lack sunlight exposure and therefore require more vitamin D. Nutritional requirements to promote longer life expectancy and freedom from disabilities that result from chronic disease include restriction of food energy and fat. Nutritional assessment of the elderly is aimed at identifying not only the presence of deficiency states but also states of nutrient excess and chronic diet-related diseases. There are certain problems in carrying out nutritional assessment in the elderly, but techniques are now available which make valid assessment possible even in the oldest old. Those who live longest have less genetic risk of premature aging, but as a result of native intelligence, education, coping skills, and higher socioeconomic status, they also have a greater likelihood of eating a diet that best meets their long-term nutritional needs. Those most at risk for developing malnutrition as they get older are those who lack food access because of poverty, because of disability resulting from chronic geriatric disease, or because of a combination of these factors. Malnutrition is found in elderly in our society who live in their own homes if they are indigent, isolated, and homebound because of disability.(ABSTRACT TRUNCATED AT 400 WORDS)