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Loss of Weight
No one knows for sure what the absolute nutritional requirements are for older people. So there are no universal, age-related reference values. A decrease in nutrient reserves probably occurs in between 9 to 15 percent of older people seen in outpatient clinics, 5 to 12 percent of home-bound people with various chronic problems, 35 to 65 percent of people hospitalized for acute illness, and 25 to 60 percent of people living in institutions.
The lack of data on people who are over age 70 makes it difficult to establish separate recommended dietary allowances (called RDAs). Table 35 lists the 1989 suggested RDAs. The current RDA continues to separate old from young people at age 51 and extrapolates many of the values for the older age group from the younger group. In addition, blood levels of nutrients such as vitamin B12 may not accurately reflect the amount in the tissues, which makes it difficult to set effective treatment guidelines. Finally, nutrient requirements need to be adjusted to reflect various interactions that affect older people whether disease-nutrient, drug-nutrient, or economic-nutrient interactions.
Table 35. Recommended Nutrient Intakes for Men and Women Ages 51 Years and Older (1989)
Total energy requirements in men decrease from about 2,700 kilocalories per day at age 30 to around 2,100 kilocalories per day at age 80. About a third of this decrease is due to the decrease in metabolic rate caused by a decline in lean body mass, and the remaining twothirds of the reduced energy requirements are probably due to decreases in energy expenditures. Recent studies have suggested that approximately one-fifth of people over the age of 60 consume fewer than 1,000 calories per day. No one is sure whether this decrease in energy intake places older people at risk for nutrient deficiencies.
It's unlikely that healthy older people suffer significant protein deficiency. The decrease in lean body mass associated with aging causes a decrease in the amount of amino acids, the building blocks for proteins. This decrease reduces the body's capacity to adapt to demands for increased protein use. As a result, protein consumption should be increased during periods of metabolic stress when, for instance, there is an infection or a broken bone. Then, the intake of protein should be increased to 1 to 1.5 grams of protein per every kilogram of body weight. This means that an elderly woman weighing 50 kilograms (110 pounds) might need to eat between 50 and 75 grams of protein each day if she develops a severe infection such as pneumonia or falls and breaks a hip. In the absence of stress, protein should make up between 10 and 15 percent of the total daily diet.
Inadequate fluid intake is one of the most common causes of salt and water disorders (electrolyte disorders) in the older age group. A common cause includes metabolic stress such as an infection, which may increase fluid requirements and impair intake, causing dehydration (see page 404). In addition, there is an age-associated decrease in the thirst sensation, a very important regulator of fluid intake. Other changes occur in the secretion of hormones such as vasopressin, which are primarily concerned with water regulation. A general goal for fluid intake should be at least two liters (about two quarts) per day.
Although uncommonly seen in noninstitutionalized elderly people, individual deficiencies of vitamins and minerals may occur. They are sometimes discovered when a physician recognizes the signs and symptoms as shown in Table 36, asks specific and detailed questions about the diet, or, more commonly, analyzes blood samples for particular nutrients. This final approach assumes that nutrient levels in the blood reflect nutrient levels in the tissue, which is not always the case.
Table 36. Clinical Manifestations of Deficient Vitamins and Minerals in Older People
A much more common and serious problem is taking too much of a vitamin (hypervitaminosis). In one study, investigators found that 10 percent of elderly men were consuming ten times the RDA for vitamins C, D, E, and B-complex vitamins, and that 10 percent of women were consuming ten times the RDA for thiamin and iron. Many older people believe that such megadoses can prolong life, cure ailments, improve their ability to deal with stress, improve sexual function, and enhance the immune system. Regretfully, the truth seems just the opposite: hypervitaminosis can result in significant toxicities. Megadoses of vitamin C can produce kidney stones and gastrointestinal problems; too much vitamin A can produce fatigue and weakness, cause liver dysfunction, headache, produce high calcium in the blood, and reduce the number of circulating white blood cells; megadoses of vitamin B6 can cause significant damage to nerves in the arms and legs.
Many factors increase the risk for malnutrition in older individuals (see Table 37). Malnutrition, in turn, places older people at risk for subsequent illness, disability, and even increased mortality. With appropriate replacement of nutritional deficiencies, most if not all of these processes can be reversed. Therefore, maintaining an adequate nutritional status is a cornerstone of preventive medicine in caring for older people.
Table 37. Causes of Malnutrition in Older People
There is no readily agreed upon definition for protein energy malnutrition in elderly people. One classification system uses body measurements and blood tests to produce two categories: inadequate intake of calories and protein (marasmus) and malnutrition in response to biologic stress (low-albumin malnutrition).
In marasmus a person loses weight while maintaining a normal level of albumin in the blood. Marasmus is also characterized by decreased amounts of body fat and muscle and a mild decline in the body's immune function. This condition is more likely to occur in older people living in the community and institutionalized elderly people. It is less likely to occur in acutely ill hospitalized elderly people.
The low-albumin form of malnutrition occurs almost exclusively as a response to infection or injury and therefore is usually seen in the hospital setting. Other causes include a very low intake (when protein makes up less than 3 percent of the total calories) or liver disease, bowel disease, or kidney disease.
Physicians generally evaluate undernutrition by clinical interview, a physical examination, and specific laboratory tests. A report of weight loss is the most important information to be obtained from the interview since this finding is the strongest predictor of death one year after hospitalization for acute illness. Weight loss during a nursing home stay is also predictive of increased disability and death. Other important clues are weakness, changes in smell or taste, abdominal pain, decreased appetite, nausea, vomiting, diarrhea, constipation, difficulty swallowing, problems chewing food or in using dentures, changes in mental status, and the presence of other significant diseases. In the nursing home, diseases or conditions that occur with undernutrition include anemia, hip fracture, pressure ulcers, depression, dementing illness, and cancer. Other important items include all medications taken (both prescription and over-the-counter drugs) and any alcohol use.
Social influences include who lives at home with the person, the person's cooking facilities, the distance from the home to the store, and the person's income. In this context, a home visit by a health professional (nurse, occupational therapist, or physician) may be extremely helpful in evaluating a person's capacity to feed himself and his ability to obtain food easily. It is also important to explore the possibility of depression and impairment of mental function.
The treatment of undernutrition should begin while the underlying cause is still being investigated. It is important for older people to be able to identify foods with high nutritional value and, if necessary, to be taught to improve their shopping and food preparation techniques, and to be encouraged to make snacks of fruits and vegetables. If necessary, the person should be given actual meal support by enrollment in such programs as Meals on Wheels or Congregate-Meals. At least once a week the calorie intake should be measured, and the weight should be taken every three to seven days, with adjustments made for periods of stress. Family members and other caregivers should be encouraged to participate in the treatment.
The treatment for institutionalized or hospitalized older people is generally oriented toward stabilizing any acute disease processes, determining the amount of calories needed, and aiming for a high intake of calories, up to 35 kilocalories per kilogram of body weight (women over 50 kilograms [110 pounds] would need 1,750 kilocalories each day). Individuals taking oral supplements such as milk shakes should be encouraged to use them as snacks rather than meal substitutes, particularly in the evening. For individuals with severe malnutrition, oral supplements may not improve the clinical situation, and tube feedings or intravenous feedings may be required. Following initial treatment with tube feedings, an increase in body weight may occur. Generally, tube feedings (or intravenous feedings) should be continued until the person has gained within 10 percent of his ideal body weight based on weightadjusted tables, or until adequate oral feedings can be tolerated.
A number of court cases have concluded that feedings can be withheld or withdrawn in individuals whose previous wishes for this action were known. In addition, competent individuals may refuse intravenous or tube feedings. Difficulties arise when individuals are depressed or incompetent or refuse to eat and yet want aggressive medical interventions if the situation warrants. In the decision-making process that precedes tube placement, active participation by the older person and family members should be encouraged and respected. (See Chapter 11 for more information on ethical issues.)
Table 38. Common Causes of Weight Loss in Elderly People
A person's weight is made up of body water, lean muscle mass, and fat. Weight loss implies low lean muscle mass and loss of fat. In older people, low lean muscle mass causes weakness and difficulty in walking and performing daily activities; low bone mass increases the risk for fractures. Relatively low amounts of body fat represent no clear danger, but this condition may reflect an increased risk for protein energy malnutrition, especially in people who develop diseases that require surgery.
Some of the common causes of weight loss in elderly people are shown in Table 38. Depression, lung cancer, other malignancies, and gastrointestinal problems are the major causes of unintentional weight loss. The greatest amount of weight loss occurs with tuberculosis and thyroid disease; however, weight loss can be an important clue to any major disease in older people. Any older person unintentionally losing more than five pounds in a six-month period needs a thorough medical evaluation.
Unexplained weight loss indicates an active problem, and it is easier to interpret weight changes when many weights over a period of time are available. The availability of many such weight records in nursing homes makes it easier to determine the degree of weight loss. For people who live in the community, it's important to obtain repeated weights. Often the physician will order blood tests to check the severity of the disorder; a blood test will reveal if the person has loss of vitality (no abnormalities) or cachexia (severe abnormalities). In either case, it's crucial to determine whether the problem is due to a loss of appetite or due to a significant medical problem. It is important to look carefully at the person's psychological state, functional ability, social situation, and mental function-- it is also important to check for depression. Screening for vision and hearing loss as well as evaluating the person's ability to perform basic activities may reveal functional causes of weight loss. The person's social situation should be evaluated for clues to the cause of weight loss and for the effects of the social condition on the person's ability to deal with problems in general. Relevant social considerations include the number of immediate family members and friends who may be able to help, and determining whether there are financial or other barriers to obtaining adequate food and housing. Living alone is the most important social factor in predicting institutionalization. The elderly person who lives alone is at increased risk for medical, functional, and psychologic problems.
Weight loss is difficult to treat, and sometimes severe malnutrition occurs even when there is adequate social, functional, and psychological support. Usually, weight loss occurs when a person simply does not eat enough. Any existing medical problems such as infection, malignancy, depression, gastrointestinal disease, and medications need appropriate management. The person's optimal food intake is estimated to set appropriate goals; the advice of a dietitian can be helpful.
If the diet taken voluntarily by the person is not adequate to maintain weight, a major decision is whether to initiate additional feedings. These feedings are usually accomplished by placing a tube from the mouth or nose into the stomach. If the underlying health problem is reversible and the person agrees to it, then tube feedings are indicated. When the person is not competent to make decisions, advanced directives such as living wills can decide whether tube feedings should begin (see Chapter 11 for more on advanced directives). One approach is to establish goals with the person, such as a specific amount of weight gain or an improvement in certain blood values such as albumin. This allows a trial of a tube feeding to begin with the understanding that if there is no improvement, the feedings will be stopped. This may be especially appropriate in very old people in whom tube feedings have a high rate of complication and questionable efficacy.
The use of medications to treat weight loss has not been fully explored. The medicines of a century ago that improved appetite and caused weight gain were widely promoted, but many of them contained poisonous substances such as strychnine. If they worked at all they did so because of their effect on taste; strychnine, for example, is very bitter. Interestingly, the use of nonpoisonous bitters as appetizers continues to be popular. Appetite stimulants have not been evaluated even though investigation in this area is appealing. From time to time the use of insulin and a variety of steroids that help promote muscle growth has been advocated for people with cancer, but their efficacy remains unproven. Recently, studies of growth hormone suggest that it reverses some of the metabolic effects that are associated with aging. This treatment is very expensive and the potential benefits are not known. It seems likely, however, that growth hormone or growth hormone-like substances may be used to treat some people who have unexplained weight loss.
In the United States approximately one-fourth of white men and one-third of white women between the ages of 65 and 76 are overweight. With advancing age there tends to be an increase in upper body (abdomen) obesity compared with lower body (hips and thighs) obesity. Upper body obesity increases the risk for diabetes mellitus, high blood pressure, and heart and blood vessel disease. In elderly people, obesity increases the likelihood of high blood pressure, diabetes mellitus, decreased functional ability, pressure ulcers, and significant sleeping problems. The risk of death increases as obesity increases.
The first step in weight reduction is an exercise program, which should be started immediately for people whose body weight is 30 percent above the average. For people with diabetes mellitus, exercise is especially important if they are 10 percent over their ideal weight. Walking is popular because it encourages socialization and can be done in an indoor environment such as a shopping mall. A physical therapist can help devise an appropriate exercise program.
Food intake should not be fewer than 1,000 calories per day. Nutritional education may be helpful to the overweight person to improve food choices (low-fat, low-calorie foods). Although there is very little information on dieting in elderly people, sudden death has been associated with various weight-reduction schemes in younger people. Because of this, fad diets, such as grapefruit diets, should all be avoided. Behavioral modification or support groups may be useful for some people.