INTRODUCTION — Changes associated with normal aging increase nutritional risk for older adults. Aging is characterized by diminished organ system reserves and weakened homeostatic controls. Data from studies of acute hospitalization in older adults suggest that up to 71 percent are at nutritional risk or are malnourished [1]. Malnutrition is associated with increased mortality risk [2].
Nutritional needs of older adults are determined by multiple factors, including specific health problems and related organ system compromise; an individual's level of activity, energy expenditure, and caloric requirements; the ability to access, prepare, ingest, and digest food; and personal food preferences.
This topic will discuss assessment of nutrition in the older adult, as well as the etiology, evaluation, and treatment of weight loss, overnutrition, and specific common nutrient deficiencies. Related issues of geriatric health maintenance and nutritional assessment are discussed separately. (See "Geriatric health maintenance" and "Approach to the patient with unintentional weight loss" and "Dietary assessment in adults" and "Vitamin intake and disease prevention".)
TERMINOLOGY — Although often used interchangeably, malnutrition and undernutrition are not synonymous. Malnutrition refers to a broader concept, which, according to the World Health Organization, encompasses undernutrition as well as overweight conditions and obesity [3]. However, in this topic, malnutrition will be used synonymously with undernutrition.
DIAGNOSTIC CRITERIA FOR MALNUTRITION — The following criteria for the diagnosis of malnutrition have been recommended in a consensus statement from the Academy of Nutrition and Dietetics (Academy) and the American Society for Parenteral and Enteral Nutrition (ASPEN) in 2012 [4]:
Two or more of the following six characteristics:
●Insufficient energy intake
●Weight loss
●Loss of muscle mass
●Loss of subcutaneous fat
●Localized or generalized fluid accumulation that may mask weight loss
●Diminished functional status as measured by handgrip strength
New criteria were introduced in 2018 from the Global Leadership Initiative on Malnutrition (GLIM). The GLIM was established in order to develop a global consensus on the identification and diagnostic criteria for malnutrition to facilitate comparison of malnutrition prevalence, treatment, and outcomes [5]. The new criteria include an appreciation of the role of acute and chronic inflammation, which is not represented in the International Classifications of Diseases 10th revision (ICD-10) codes.
The diagnosis requires the combination of at least one phenotype and one etiologic criteria:
●Phenotype criteria – Non-volitional weight loss, low body mass index (BMI), or reduced muscle mass.
●Etiologic criteria – Reduced food intake or absorption, or underlying inflammation due to acute disease/injury or chronic disease.
After making the diagnosis of malnutrition, a more comprehensive assessment of nutritional status can be performed by dietitians or nutritionists, who can develop individualized care and treatment plans.
MALNUTRITION PREVALENCE — The prevalence of malnutrition in older adults is dependent upon the population studied, varying by geography, age distribution, and living situation.
●A review of results of the Mini Nutritional Assessment (MNA) across settings and countries in Europe, the United States, and South Africa found the prevalence of malnutrition among 4507 older adults (mean age 82.3, 75.2 percent female) was 22.8 percent [6]. Highest rates were in the rehabilitation setting (50.5 percent) and lowest among community dwellers (5.8 percent). Over one-third of hospitalized older adults (38.7 percent) in this study met the criteria for malnutrition.
●In a 2016 meta-analysis on malnutrition in various health care settings (mostly in Europe), including data from 240 studies and over 110,000 persons, rates of malnutrition were: outpatients, 6.0 percent (95% CI, 4.6-7.5); hospital, 22.0 percent (95% CI, 18.9-22.5); nursing homes, 17.5 percent (95% CI, 14.3-20.6); long-term care, 28.7 percent (95% CI, 21.4-36.0); rehabilitation/sub-acute care, 29.4 percent (95% CI, 21.7-36.9) [7].
SCREENING FOR NUTRITIONAL STATUS — Elements of screening include measuring weight, calculating weight loss, and utilizing screening tools.
Weight — Serial measurements of body weight offer the simplest screen for nutritional adequacy and change in nutritional status in older adults.
Obtaining periodic body weights may be challenging, particularly in frail patients. A chair or bed scale that is regularly calibrated may be needed for patients who cannot stand on an upright balance beam scale. Low body weight is defined as <80 percent of the recommended body weight (table 1).
Weight loss — Studies suggest that weight loss in older adults, especially if it is not volitional, is predictive of mortality [2,8,9]. Loss of as little as 5 percent of weight over a three-year period is associated with increased mortality among community-dwelling older adults [10].
Weight loss for those with a body mass index (BMI) below 30 likely poses a greater mortality threat to older adults than not losing weight or of having a BMI of 25 to 30 [11]. However, obesity (BMI ≥30) continues to have a negative impact on morbidity and mortality in older adults. The relative benefit of intentional weight loss in obese older adults with osteoarthritis, impaired activity tolerance, diabetes mellitus, and coronary heart disease, especially when combined with exercise, is becoming increasingly apparent [12-14].
Weight loss is considered to be clinically significant with the following parameters [15]:
●≥2 percent decrease of baseline body weight in one month
●≥5 percent decrease in three months, or
●≥10 percent in six months
In the long-term care setting, a clinically significant weight-loss episode is defined by the long-term care Minimum Data Set (MDS) as loss of 5 percent of usual body weight in 30 days, or 10 percent in six months [16].
Screening tools — A number of screening tools have been developed for identifying older adults at risk for poor nutrition. The two screening tools in the highest quartile for sensitivity (>83 percent) and specificity (>90 percent) were the MNA (SF) and the MST [17]. The MNA is used most often by nutritionists. The most commonly used screening tools include those listed below:
●The Nutritional Risk Screening (NRS) 2002 has two components: a screening assessment for undernutrition and an estimate for disease severity. Undernutrition is estimated with three variables: BMI, percent recent weight loss, and change in food intake [18]. Disease severity ranges from a score of zero (for those with chronic illnesses or a hip fracture) to three (for those in the intensive care unit [ICU] with an APACHE score of 10). In hospitalized patients, the NRS 2002 showed a sensitivity of 39 to 70 percent and a specificity of 83 to 93 percent when compared with the Mini Nutritional Assessment and the Subjective Global Assessment [17].
●The Simplified Nutrition Assessment Questionnaire (SNAQ), a four-item screener, was tested in community-dwelling older adults and long-term care residents [19]. In those populations, it had a sensitivity and specificity of 81.3 and 76.4, and 88.2 and 83.5 percent, respectively, for identification of older persons at risk for 5 and 10 percent weight loss, respectively (figure 1).
●SCREEN II (Seniors in the Community: Risk Evaluation for Eating and Nutrition) is a 17-item tool that assesses nutritional risk by evaluating food intake, physiological barriers to eating (difficulty with chewing or swallowing), weight change, and social/functional barriers to eating. The tool has excellent sensitivity and specificity, as well as interrater and test/retest reliability [20]. An eight-question abbreviated version of SCREEN II is also available [21].
●The Malnutrition Universal Screening Tool (MUST) incorporates BMI, weight loss in three to six months, and anorexia for five days due to disease. When neither height nor weight is available, the midarm circumference and subjective assessment of physical characteristics, such as very thin, can be used instead. It is commonly used in the United Kingdom and is particularly sensitive for recognition of protein energy undernutrition in hospitalized patients [22].
●The Malnutrition Screening Tool (MST) was developed for use in acutely hospitalized patients and also validated for use in cancer patients (average age 57 to 60 years, range 15 to 89) [23]. It asks two simple questions: "Have you been eating poorly because of a decreased appetite?" and "Have you lost weight recently without trying?" The sensitivity of the MST in hospitalized patients ranges from 74 to 100 percent with a specificity of 76 to 93 percent when compared with the Subjective Global Assessment.
●The Mini Nutritional Assessment (MNA) consists of a global assessment and subjective perception of health, as well as questions specific to diet, and a series of body measurements [24]. It has been widely validated and is predictive of poor outcomes [25-27]. The Mini Nutritional Assessment-Short Form (MNA-SF) uses six questions from the full MNA and can substitute calf circumference if BMI is not available. A validation study demonstrated good sensitivity compared with the full MNA [28].
MALNUTRITION — Compared with younger adults, undernutrition in older individuals is both more common and may have greater impact on outcomes, including physical function [29], health care utilization [30], and length of stay for surgical hospitalizations [31,32]. Inadequate energy intake is common in hospitalized older adults, with increased risk associated with poor appetite, higher body mass index (BMI), diagnosis of infection or cancer, delirium, and need for assistance with feeding [33]. Some studies suggest that older adults are less able to adapt to underfeeding. One study found that, following a period of experimental underfeeding, older adults experienced less frequent hunger than younger adults and did not regain the total amount of weight they had lost when allowed to consume food freely for six months while, on average, younger adults regained all their lost weight [34]. By contrast, a similar study did not demonstrate age differences in ad libitum intake, anthropometric indices, gastric emptying rate, and cholecystokinin levels in blood after a period of underfeeding and then consumption of food freely [35].
The lack of ability to compensate for periods of low food intake due to illness or other difficulties can result in long-term, persistent weight changes, especially when combined with social, medical, or psychological factors that can negatively impact body weight.
Involuntary weight loss may be driven by a variety of factors, including:
●Inadequate dietary intake
●Appetite loss (anorexia)
●Disuse or muscle atrophy (sarcopenia)
●Inflammatory effects of disease (cachexia)
or a combination of these factors.
Inadequate dietary intake — There are multiple causes of weight loss due to inadequate nutrient intake. These include social (eg, poverty, isolation), psychological (eg, depression, dementia), medical (eg, edentulism, dysphagia), and pharmacologic issues.
Social factors — Social factors contributing to weight loss include:
●Increased likelihood of isolation at mealtimes. One-third of persons over 65 and one-half over 85 live alone, which typically decreases food enjoyment and calorie intake. Several studies have demonstrated that older adults who eat in the presence of others consume more than those who eat alone [36,37].
●Financial limitations affecting food acquisition. A greater proportion of older adults live near the poverty line, compared with the general population. Individuals with fixed incomes may use money previously spent on food for medications and other needed items.
Medical and psychiatric factors — The most important medical and psychiatric causes of weight loss in older adults are malignancy and depression.
●Malignancy was identified as the cause for weight loss in 9 percent of older patients in a study of medical outpatients, and was second to depression as the most frequent identifiable cause of undernutrition [38]. In another study of unexplained weight loss in 45 ambulatory older adults, the most common identified cause for weight loss was depression (18 percent), again followed by malignancy (16 percent) [39]. A third report found cancer, predominantly of the gastrointestinal tract, as a cause of weight loss in 36 percent of the 154 patients evaluated [40].
●Depression and dysphoria are common in older adults and often remain unrecognized and undertreated. Depression is an important cause of weight loss in the subacute care and nursing home settings, as well as in older patients in the community. In a chart review of 1017 medical outpatients, for example, depression was the cause of weight loss in 30 percent of the older patients, compared with only 15 percent in younger patients [38]. (See "Diagnosis and management of late-life unipolar depression".)
Dysphagia is present in approximately 7 to 10 percent of the older adult population [41] and has a negative effect on energy intake [42]. Dysphagia occurs in approximately one-half of patients with acute first-ever stroke [43] or with Parkinson disease [44]. Oropharyngeal dysphagia may occur due to stroke, Parkinson disease, amyotrophic lateral sclerosis, Zenker's diverticula, and other motility or structural disorders. Esophageal dysphagia can be due to motility problems (eg, achalasia, diffuse esophageal spasm, scleroderma) and structural issues. (See "Approach to the evaluation of dysphagia in adults".)
Other important medical etiologies to consider include:
●Endocrine disorders (hyperthyroidism, new onset diabetes mellitus)
●End-organ disease (congestive heart failure, end-stage kidney disease, chronic obstructive pulmonary disease, hepatic failure)
●Gastrointestinal disorders (celiac disease, ischemic bowel, inflammatory bowel disease, pancreatic insufficiency, peptic ulcer disease, gastroesophageal reflux disease)
Infections (tuberculosis)
●Rheumatologic disorders (polymyalgia rheumatica, rheumatoid arthritis)
●Neurologic conditions (Parkinson disease, chronic pain)
●Alzheimer disease (especially among those with behavioral and psychological symptoms) [45]
●Drug or alcohol dependence
●Medication side effects (digoxin, opioids, serotonin-reuptake inhibitors, diuretics, and topiramate)
Additionally, medical or dental conditions in older adults may impair the ability to eat. Paralysis from stroke, severe arthritis, hand tremors, and dementia may lead to routine need for feeding assistance from others.
Chewing difficulty and oral pain puts older adults at risk for poor intake. In a study of noninstitutionalized older adults, being edentulous doubled the risk for significant weight loss over a one-year period, after adjusting for sex, income, age, and baseline weight [46]. In a separate analysis of 992 older adults in the Laussane 65+ cohort study, those with oral pain and chewing problems had higher odds of being frail; oral pain was also associated with weight loss and low hand grip [47].
Physiologic factors — Physiologic factors associated with weight loss include age-related decrease in taste and smell sensitivity, delayed gastric emptying, early satiety, and impairment in the regulation of food intake.
●Age raises the threshold for odor detection and lowers perceived odor intensity [48]. The number of taste buds remains constant, but thresholds for recognition of salt and other specific tastes increase. Impaired taste and smell likely alter the cephalic phase of digestion, affecting learned associations between the taste and smell of food with signals involved in meal initiation, volume of food intake, and meal termination.
●Decrease in the rate of gastric emptying in older adults may result in prolonged antral distension with reduced hunger and increased satiety [49].
●Aging may influence production of, and/or central nervous system sensitivity to, several digestive hormones thought to be involved in satiety. Glucagon, glucagon-like peptide-1 (GLP-1), cholecystokinin (CCK), leptin, and ghrelin are peripheral satiety signals and appear to be less well-detected by the brain with increased age [50].
●Causes of impaired regulation of food intake include decreased stimulatory effects of neurotransmitters involved in appetite (eg, opioids, neuropeptide Y, the orexins and ghrelin) and increased sensitivity to the inhibitory effects of corticotropin-releasing factor, serotonin, and cholecystokinin.
Anorexia — Anorexia, the decrease in appetite, in older adults is influenced by multiple physiological changes. Food intake gradually diminishes with age [51]. Much of the intake reduction in early old age is an appropriate response to decreased energy needs due to reduced physical activity, decreased resting energy expenditure (REE), and/or loss of lean body mass.
Changes in taste and smell lead to a decreased desire to eat and early satiety develops with age, related to gastrointestinal changes and gastric hormone changes, as discussed above. (See 'Physiologic factors' above.)
Appetite regulation is further affected by illness, drugs, dementia, and mood disorders. In 292 older adults from assisted living facilities or senior centers, fair to poor emotional well-being was most closely associated with poor appetite (odds ratio [OR] 5.60, 95% CI 2.60-12.07) [52]. In a study of 526 older Italians, the prevalence of anorexia was 21 percent and was more common in those living in institutional settings, with impairment of Instrumental Activities of Daily Living (IADL) and fewer residual teeth [51].
Cachexia — Cachexia has been defined as a "complex metabolic syndrome associated with underlying illness, and characterized by loss of muscle with or without loss of fat mass" [53]. It is associated with increased morbidity. Anorexia, inflammation, insulin resistance, and increased muscle protein breakdown are frequently associated with cachexia.
Cachexia is distinct from starvation, age-related loss of muscle mass (see 'Sarcopenia' below), or psychiatric, intestinal, or endocrinologic causes of weight loss. Cachexia involves many dysregulated pathways, leading to an imbalance between catabolism and anabolism. Because of the presence of underlying inflammation and catabolism, cachexia often is resistant to nutritional intervention. Despite the evidence supporting inflammation as an essential mechanism for cachexia, antiinflammatory medications or drugs targeting cytokines have not demonstrated beneficial effects [54]. Potential drugs such as thalidomide, selective cyclooxygenase (COX) inhibitors, w3-fatty acids like eicosapentaenoic acid, and anti-tumor necrosis factor (TNF) agents have shown variable efficacy in treating cachexia [54]. The cause of cachexia is multifactorial, and thus treatment should be multimodal, including the use of a combination of an appetite stimulant and an agent promoting muscle protein synthesis [55].
Cachexia usually occurs in the setting of underlying illness involving a cytokine-mediated response. Such illnesses include cancer, end-stage kidney disease, chronic pulmonary disease, heart failure, rheumatoid arthritis, and acquired immunodeficiency syndrome (AIDS).
Proinflammatory cytokines commonly involved in cachexia include interleukin (IL)-1, IL-6, and TNF-alpha (TNF-a) [56,57]. These cytokines promote myofibrillar breakdown by activating the ubiquitin proteasome pathway. In addition, release of cortisol and adrenergic hormones stimulated by cytokines can increase fat oxidation, fat atrophy, insulin resistance, hypermetabolism, and fatigue [55].
In a study of older Framingham Heart Study participants, levels of insulin-like growth factor (IGF)-1 and muscle mass decreased, whereas IL-6 levels increased, with age [58]. These changes appear to occur even in the absence of overt disease, suggesting that a subclinical inflammatory process may be part of normal aging. Although elevated proinflammatory cytokines (especially IL-1, IL-6 and TNF-a) are commonly seen in older adults, levels are higher in those with cachexia.
Sarcopenia — Sarcopenia is a syndrome characterized by the loss of muscle mass, strength, and performance [59-61]. Low muscle mass is defined as a decrease in appendicular muscle mass two standard deviations below the mean for young healthy adults [62], and is usually measured by DEXA or bio-electrical impedance in clinical practice. Unlike cachexia, sarcopenia does not require the presence of an underlying illness. Also, whereas most people with cachexia are sarcopenic, most sarcopenic individuals are not considered cachectic [63]. Sarcopenia is associated with increased rates of functional impairment, disability, falls, and mortality [64]. The causes of sarcopenia are multifactorial and can include disuse, changing endocrine function, chronic diseases, inflammation, insulin resistance, and nutritional deficiencies [61].
Sarcopenia was identified in 53 to 57 percent of men, and 43 to 60 percent of women, over the age of 80 in one study [65]. Loss of muscle mass, accompanied by decreased muscle strength, can occur in overweight individuals (sarcopenic-obese), as well as in normal and underweight individuals.
Causes of sarcopenia include endocrine changes, activation of proinflammatory cytokines, reduced alpha motor units in the spinal cord, decreased physical activity, and suboptimal protein intake.
●Reductions in testosterone and estrogen that accompany aging appear to accelerate the development of sarcopenia [66]. Relative deficiencies of estrogen and testosterone contribute to muscle catabolism and promotion of catabolic cytokines such as IL-1 and IL-6 [34]. Furthermore, testosterone inhibits myostatin, stimulates myoblast, and increases satellite cells within muscle. Testosterone replacement may increase muscle mass, but studies have not demonstrated similar benefit for estrogen replacement [67-69]. Selective androgen receptor modulators (SARM), such as enobosarm, are a promising potential treatment for sarcopenia. A phase II trial of enobosarm in healthy older adults led to increases in lean body mass and improvement in stair climbing [70].
●Insulin resistance increases with age. Insulin inhibits muscle breakdown and the reduction of insulin action on muscle may contribute to muscle catabolism [71].
●Physical activity declines with age. In the United States, 28 to 34 percent of adults aged 65 to 74 and 35 to 44 percent of adults ages 75 or older are inactive [72]. Inactivity exacerbates ongoing muscle loss [73] and increases proportion of body fat mass [74].
●Inadequate protein intake can also contribute to sarcopenia and decreased function. A prospective cohort study found that adults aged 70 to 79 with protein intake ≤0.8 g/kg/day (the Recommended Dietary Allowance [RDA]) were at greater risk of developing mobility limitations over six years of follow-up than those with protein intake ≥1.0 g/kg/day [75].
EVALUATION OF WEIGHT LOSS — Recommendations vary on the degree of weight loss, and the period of time for weight loss, that should prompt clinical investigation. One commonly accepted definition for clinically important weight loss is loss of 4 to 5 percent of total body weight over 6 to 12 months [2]. Unintentional weight loss should lead to clinical concern regardless of whether the patient is overweight at baseline. Whether or not intentional weight loss is of concern remains a matter of some speculation.
Initial evaluation — The following steps are suggested in the initial evaluation of an older person who is noted to have lost weight, or for whom concern is raised about weight loss by the patient, family members, or caregivers.
●Document the weight loss. While it is important to note objective evidence of weight loss from recorded serial weights over time, this information is often not available.
Body fat and lean muscle mass may be estimated using bioelectrical impedance or anthropometric measures such as mean upper arm circumference (MUAC) or mid-arm circumference. MUAC measures the circumference of the left upper arm at the mid-point between the tip of the shoulder and the tip of the elbow (olecranon process and the acromion). MUAC of less than 22 cm for women and 23 cm for men are suggestive of chronic energy deficiency. Although suggestive of malnutrition, it is unclear whether MUAC predicts mortality and morbidity. The MUST screening tool uses mid-arm circumference measures.
Bioelectrical impedance measures are available for use with wheelchair- and bedbound patients, although bioelectrical impedance is significantly influenced by hydration status.
●Evaluate appetite and dietary intake. Determining if there has been a change in hunger and satiety may provide more clinically revealing information than performing a formal dietary recall. Patients should be questioned regarding appetite, their dietary intake in relation to their usual pattern, the number of meals they consume per day, portion size, snacks between meals, if and when they feel full during their meal, and whether the patient likes what they are eating. The Subjective Global Assessment (SGA), Mini Nutritional Assessment (MNA), and Simplified Nutritional Appetite Questionnaire (SNAQ) all evaluate aspects of dietary intake in this way (see 'Screening tools' above). A more formal dietary intake assessment can be obtained with a dietetic consult.
●Perform a complete history, including oral symptoms, and physical examination, including a complete oral examination. As a baseline, we suggest laboratory evaluation for evidence of metabolic or inflammatory disease, to include a basic chemistry profile including glucose and electrolytes, thyroid-stimulating hormone (TSH), complete blood count (CBC), and C-reactive protein (CRP) if cachexia is suspected. Chest and plain abdomen radiographs may be considered. Although studies describing the causes of involuntary weight loss have routinely performed chest radiographs and abdominal films, there is no clear evidence of their value. Order additional studies based on suspicion of underlying disease from the patient's history and examination.
Those with no localizing findings and with normal complete blood count, biochemical profile, or chest and plain abdomen radiographs have been considered by some to have isolated involuntary weight loss [76]. In one series, a little more than one-third of patients were ultimately diagnosed with a malignancy. Multivariate analysis found the strongest predictors of neoplasm in the setting of isolated involuntary weight loss were age >80 years, white blood cell count >12,000/mm3, serum albumin <3.5 g/dL, serum alkaline phosphatase > 300 IU/L, and serum lactate dehydrogenase (LDH) >500 IU/L. These authors recommend CBC, erythrocyte sedimentation rate (ESR), serum albumin, liver function studies, LDH, and abdominal ultrasound.
Subsequent evaluation — There are no clear guidelines for how to proceed in the assessment of a patient with weight loss and negative initial findings. The diagnostic yield of a thoracic/abdominal/pelvic computed tomography (CT) examination to assess for occult or metastatic malignant disease has not been determined. Incidental findings are common, the studies are costly, and may be inappropriate in patients who are frail or who have multiple comorbidities.
●In the absence of evidence-based recommendations, we suggest ordering a thoracic/abdominal/pelvic CT scan with and without contrast for the patient with significant ongoing weight loss. Magnetic resonance imaging (MRI) may be ordered as an alternative when intravenous (IV) contrast cannot be administered, assuming there are no contraindications; patients with chronic kidney failure should not be given gadolinium. (See "Nephrogenic systemic fibrosis/nephrogenic fibrosing dermopathy in advanced kidney disease".)
●Upper gastrointestinal endoscopy is indicated for patients with early satiety.
●Colonoscopy is not indicated in the evaluation of weight loss unless the patient simultaneously has signs of gastrointestinal blood loss, as colon cancer does not usually induce weight loss or cachexia unless there is obstruction or extensive metastases [77,78].
TREATMENT OF WEIGHT LOSS — When an underlying cause of weight loss is identified, such as depression, a medical illness, or inability to chew food, it is obviously important to treat the condition. In addition, nutritional repletion should be provided to restore the patient to a target weight, with recognition that weight correction in the older population is less readily accomplished than in younger people.
The Council for Nutritional Clinical Strategies in Long-Term Care has developed an evidence-based approach to nutritional surveillance and management for patients in long-term care [79]. Treatment recommendations are based on common reversible causes of malnutrition, as described by the acronym "MEALS ON WHEELS" (table 2). Likewise, the American Academy of Home Care Physicians has developed guidelines for unintended weight loss in home care patients [80].
Data from studies of acute hospitalization in older patients suggest that up to 71 percent are at nutritional risk or are malnourished [1]. One randomized trial found that individualized nutritional management by a dietitian (involving one visit during hospitalization and three home visits subsequent to discharge) resulted in improved scores on the Mini Nutritional Assessment (MNA) and higher albumin levels in the intervention group, compared with controls [81]. Decreased mortality rates at six months were also found (3.8 versus 11.6 percent for intervention and controls respectively), although high study dropout rates and issues with randomization allocation may have impacted this finding.
Calorie and protein requirements — Calorie needs (the estimated energy requirement [EER]) can be calculated in older adults using the following equations [82]:
●For women: 354.1 – (6.91 x age [y]) + PAC x (9.36 x weight [kg] + 726 x height [m]).
●For men: 661.8 – (9.53 x age [y]) + PAC x (15.91 x weight [kg] + 539.6 x height [m]).
The Physical Activity Coefficient (PAC) is determined as follows:
●Sedentary PAC = 1.0
●Low activity PAC = 1.12
●Active PAC = 1.27
●Very active PAC = 1.45
Protein needs do not appear to change significantly with age, although studies evaluating protein intake in older adults have shown wide variation in optimal protein requirements. A meta-analysis of data from 19 studies of nitrogen balance in older adults found no significant effect of age on the amount of protein required per kilogram of body weight [83].
The Institute of Medicine has determined that the Recommended Dietary Allowance (RDA) for protein for adults 51 years of age and older is 0.80 g/kg body weight/day [84]. However, subsequent studies indicate that protein intake above 0.08 g/kg body weight/day is protective of appendicular lean mass and preservation of handgrip strength and decreases the risk of functional disability [85-87].
Inadequate food intake — If the patient's food intake is inadequate:
●Lift dietary restrictions whenever possible. In one study, undernutrition (average weight loss >1 pound per month, serum albumin <3.5 g/dL) was associated with dietary restrictions [88]. Fifty-nine percent of the patients with weight loss and 75.2 percent of those with hypoalbuminemia were on some type of dietary restriction.
In older, nutritionally high-risk adults with diabetes, regular monitoring of blood glucose and adjustment of medication is preferable to dietary restriction or even a "no concentrated sweets" prescription. The short-term substitution of a regular diet for a diabetic diet increased calorie consumption and did not cause gross deterioration of glycemic control in a study of chronic care patients with type 2 diabetes [89].
●Make sure that feeding or shopping assistance is available, if appropriate. In a crossover controlled trial of feeding assistance in nursing home residents at risk of weight loss, those in the intervention group showed a significant increase in daily caloric intake and either maintained or gained weight, whereas those in the control group lost weight. Feeding assistance was resource-intensive and required an average 37 more minutes of staff time per meal [90]. Social work support may be important if inadequate finances are contributing to poor intake.
●Assure that meals and foods meet individual tastes. Suggest offering foods that fit the patient's ethnic or regional preferences.
●Consider ways to supplement the patient's diet. Increase the nutrient density of food. For example, increase protein content by adding milk powder, whey protein (found in many health food stores), egg whites, or tofu. Increase fat content by adding olive oil (or other "good fat") in preparation of sauces, fresh or cooked vegetables, and grains or pasta. If weight does not improve, offer daytime snacks between meals.
●Give a daily multivitamin and mineral supplement until the cause of inadequate intake is determined.
●Consider a liquid dietary supplement. (See 'Nutritional supplements' below.)
Nutritional supplements — A meta-analysis evaluated 55 randomized trials of nutritional supplements containing protein and energy to prevent malnutrition in older, high-risk patients [80]. Studies were generally judged to be of poor quality, due to lack of blinding and intent to treat analysis. The trials evaluated supplements providing between 175 and 1000 additional kcal/day and between 10 and 36 grams protein/day. Most subjects (45 percent) were hospitalized for stroke; 16 percent were community-based and 10 percent were in long-term care facilities.
Nutritional supplementation resulted in modest improvement in percentage weight change (weighted mean difference 1.75 percent, 95% CI 1.2 to 2.3), with slightly greater weight increase in patients at home or in long-term care. Overall mortality was reduced in the groups receiving nutritional supplement, compared with control, but there was no mortality impact for patients living at home, and no improvement in functional status. The greatest mortality impact was found in hospitalized undernourished patients who were 75 years or older and who received supplements with higher calorie content. Complication rates were lower for hospitalized patients who received supplementation, but there was no change in hospital length of stay.
In another meta-analysis, there was some evidence that volitional nutrient support (VNS) improved survival among malnourished geriatric patients [91]. Findings were significant for low-quality trials; two high-quality trials found benefit for VNS in this population, but the difference from control did not reach statistical significance. In a systematic review including 32 trials for a total of 4137 older adults, multi-nutrient supplements improved chair rise time and handgrip strength [92].
A randomized crossover trial of amino acid supplements in 41 sarcopenic older adults demonstrated increases in whole-body lean mass at 6 and 12 months. This study also demonstrated that supplementation led to improved nutrition as reflected by Mini Nutritional Assessment (MNA) scores, improved albumin levels, decreased scores for depression measured by the Geriatric Depression Scale (GDS), and better hand grip strength [93]. More studies are needed in the sarcopenic geriatric population before amino acid supplementation can be generally recommended in clinical practice [94].
Appetite stimulants — Use of appetite stimulants (orexigenics) may be considered, but with caution. There are few studies of use of these medications in the older population with weight loss and failure to thrive. There is inadequate information to determine the appropriate use of orexigenics in older adults with cachexia. If used, they should be used as a trial and evaluated for any benefit before continuing stimulants. The complex interplay between inflammation, catabolism, and nutritional substrate in cachexia demands multimodal interventions that address all three elements.
Megestrol acetate — Megestrol acetate, a progestational agent, has been shown to yield weight gain in patients with anorexia and cachexia. Megestrol acetate has demonstrated some weight gain and improved appetite in patients with cancer or acquired immunodeficiency syndrome (AIDS) cachexia [95-97].
In a randomized trial, megestrol acetate 800 mg daily for 12 weeks improved appetite and sense of wellbeing in a group of nursing home residents. However, weight gain was not found to be significant (>4 lbs) until three months after treatment [98]. Weight gain was more prominent in residents with elevated cytokine concentrations.
There are significant adverse effects of megestrol acetate. Patients should be monitored for edema and worsening of congestive heart failure, impaired function of the corticoadrenal axis [99], deep venous thrombosis [100], and muscle weakness. The use of megestrol in older adult nursing home residents has been associated with increase in all-cause mortality without increase in weight [101]. Due to these adverse effects, the 2015 Beer’s criteria list megestrol acetate as potentially inappropriate for patients 65 years and older [102]. We suggest that this medication should only be considered in older adults with cancer or AIDS cachexia for a limited trial to stimulate appetite.
Dronabinol — Dronabinol has been shown to improve appetite in patients with AIDS [103]; it was not as effective as megestrol in patients with advanced cancer [104]. Dronabinol has not been well-studied in older adults [105,106], although one nonrandomized trial showed that dronabinol may be useful for anorexia, weight gain, and behavior problems in patients with advanced Alzheimer disease who were refusing food [105]. Dronabinol has significant central nervous system side effects, limiting its use for most older adult populations.
Mirtazapine — Mirtazapine, an antidepressant that leads to more weight gain than selective serotonin reuptake inhibitor (SSRI) antidepressants, is commonly used for management of depression and weight loss in older adults. However, few studies have been specifically performed to evaluate its impact on weight among older adults with weight loss. Two studies in nursing home residents did not show conclusive benefit for mirtazapine over other non-tricyclic antidepressants [107,108]. However, a retrospective study in patients with Alzheimer disease and weight loss found that patients treated with mirtazapine for three months gained an average of 2 kg compared with baseline [109].
Ghrelin mimetics (growth hormone secretagogues) — Ghrelin is an endogenous growth hormone secretagogues (GHS) that has been shown to stimulate appetite and increase fat-free mass. Two randomized trials of GHS in healthy older adults demonstrated increases in lean mass (average gain of 1.6 kg), and improvements in strength and function compared with placebo [110,111]. One trial of capromorelin also found a gain in functional abilities (eg, tandem gait distance and stair-climbing) [110]. Further trials are necessary to assess the benefit and safety of GHS in the treatment of older adults with sarcopenia, cachexia, or weight loss. Adverse effects of ghrelin mimetics include hyperglycemia, dizziness, and nausea.
OVERNUTRITION — The National Heart, Lung, and Blood Institute clinical guidelines define overweight as a body mass index (BMI) of 25 to 29.9 and obesity as a BMI of 30 or greater [112,113]. For older adults, BMI and weight may not be reliable indicators of overweight or obesity in older populations, where normal weight may reflect loss of muscle mass rather than decreased adiposity. There is no consensus on the best method of measurement of obesity in older patients [114].
For the population as a whole, higher body weights are associated with increase in all-cause mortality, as well as morbidity related to hypertension, dyslipidemia, type 2 diabetes, coronary heart disease, stroke, gallbladder disease, osteoarthritis, sleep apnea and respiratory problems, and endometrial, breast, prostate, and colon cancers.
However, several studies suggest that the relationship of overweight or obesity to mortality declines over time [115]:
●Data from the Longitudinal Study of Aging found that a relatively high BMI (30 to 35 for women and 27 to 30 for men) was associated with minimal excess risk for mortality in adults older than 70 years of age [116].
●A longitudinal study of over 500,000 adults in the United States found a decrease in the association of obesity with cardiovascular disease mortality over time [117].
●Data from several other long-term observational studies, including the Cardiovascular Health Study [118,119], the Medicare Current Beneficiary Surveys [120], and the National Long Term Care Survey [121] have also found that being overweight does not increase mortality risk for people age 65 years and older.
A few studies suggest that being overweight as an older adult is associated with increased mortality:
●In a study of men 60 to 79 years in the United Kingdom, mortality was not increased for overweight or obese participants as defined by BMI [122]. However, mortality risk was increased with increasing waist circumference and with BMI, when data were corrected for differences in mid-arm muscle circumference. These findings suggest that cardiorespiratory fitness and muscle mass may play an important role in the relationship between BMI and mortality.
●Another report found a U-shaped pattern in women ≥65 years of age, comparing mortality across weight quintiles, with lower mortality for women in the middle 3 quintiles [123]. A J-shaped pattern for BMI and mortality was demonstrated in another study of adults, predominantly men, over age 60 [124]. In this study, BMI in the overweight range was protective.
Although the mortality risk of obesity may lessen with age, there are still metabolic and functional benefits to weight loss in obese older adults. Increasing obesity in older adults is associated with new or worsening disability [120], and weight loss can improve physical function, blood glucose and cholesterol levels, and quality of life [125,126]. Recommendations to lose weight should be individualized to the risk profile of particular patients. Those who are experiencing significant adverse effects associated with obesity (such as pain from osteoarthritis, obstructive sleep apnea, poor mobility, and falls) should be encouraged to pursue cautious weight loss. Few randomized controlled clinical trials have shown that diet and exercise combination can lead to successful weight loss and improve cardiometabolic risk factors and physical function for obesity older adults without adverse effects [14,127,128], but only in the context of regular exercise and appropriate calcium and vitamin D supplementation. Negative outcomes associated with weight loss in overweight older adults include loss of muscle mass and decrease in bone mineral density; both of these may be mitigated with regular exercise and vitamin D supplementation [129-132].
Sarcopenic obesity is a combination of age-related muscle atrophy and increase in adiposity, and this condition have been associated with increased mortality rate and greater risk for falls and cognitive impairment [133,134]. Several clinical trials of high-protein weight-loss diets have demonstrated success in weight loss while preserving lean mass and function [135,136]. Porter Starr et al randomized 67 obese older adults (BMI mean 36.9 ± 6.3) to normal weight loss diet and high-protein weight-loss diet for six months. Both groups lost significant weight loss, but the high-protein diet group improved their Short Physical Performance Battery score compared with the control group [137].
MICRONUTRIENT DEFICIENCIES IN OLDER ADULTS
Vitamin B12 deficiency — The prevalence of B12 deficiency in older adults ranges between 10 and 20 percent [138]. Some persons with low normal serum B12 levels may in fact be deficient, with resultant neurologic, psychological, or hematologic disease [139]. The diagnosis may need to be made by measurement of methyl malonic acid, which is elevated with B12 deficiency. (See "Clinical manifestations and diagnosis of vitamin B12 and folate deficiency".)
In the past, a majority of B12 deficiencies were thought to result from intrinsic factor deficiency. It is now known that approximately 15 percent of older adults (>60 years) poorly absorb protein-bound B12 [140]. This is a result of malabsorption of the food-protein-B12 complex in the stomach, related to gastric achlorhydria and often associated with atrophic gastritis [140]. This may be consequent to current or past Helicobacter pylori infection.
Concern had been raised that folate fortification of foods may mask macrocytic anemia in those with vitamin B12 deficiency. However, a study using National Health and Nutrition Examination Survey (NHANES) data for older adults in the post-folate fortification years found that those with B12 deficiency and higher folate levels were more likely to be anemic and to have cognitive impairment than patients with normal folate levels [141].
Given the high prevalence of B12 deficiency and the ease and safety of treatment, some have advocated routinely screening adults over the age of 65 with a serum vitamin B12 assay [142]. However, this policy has not been endorsed in formal screening guidelines for the geriatric population.
Patients with B12 deficiency can generally be treated with oral B12 and may benefit from increasing the intake of B12 in food [143]. Because B12 malabsorption is common in older adults, with potentially significant effects of vitamin B12 deficiency on the nervous system, individuals >51 years of age should take supplements containing vitamin B12, or eat fortified food products. It is prudent to advocate a daily intake of 10 to 15 mcg [144]. For food cobalamin malabsorption-induced B12 deficiency, ongoing therapy with 1000 mcg per day of oral crystalline cyanocobalamin may correct serum vitamin B12 levels and yield adequate hematological responses [145].
Vitamin D deficiency — Lack of sun exposure, impaired skin synthesis of pre-vitamin D, and decreased hydroxylation in the kidney with advancing age contribute to marginal vitamin D status in many older adults [146]. In addition, dietary vitamin D intake is often low in older subjects. It has been estimated that approximately one-half of older women consume less than 137 international units/day of vitamin D from food, and nearly one-quarter consume less than 65 units/day [147]. However, the US Preventive Services Task Force (USPSTF) concluded that screening for vitamin D levels in asymptomatic adults to improve health outcomes lacks sufficient evidence [148]. A large trial, VITAL (Vitamin D and Omega A-3 Trial), is underway to investigate the efficacy of vitamin D supplementation on the prevention of cancer and cardiovascular diseases [149].
Inadequate vitamin D status has been linked with muscle weakness, functional impairment, depression, and increased risk of falls and fractures [150-152]. An observational study in a large integrated health care system found an association between low vitamin D and increased prevalence of diabetes, hypertension, hyperlipidemia, and peripheral vascular disease [153]. A meta-analysis found an association between low vitamin D levels and increased all-cause mortality as well as cardiovascular disease-related mortality and cancer mortality [154]. Lower serum 25-hydroxyvitamin D concentrations in older persons have also been associated with a greater risk of future nursing home admission [155]. Patients with vitamin D insufficiency may also have relative hypocalcemia and high serum parathyroid hormone (PTH) concentrations; this secondary hyperparathyroidism can be attenuated by the administration of vitamin D supplements [156-158]. Some studies have indicated an association between low vitamin D and certain cancers, such as colorectal cancer [159].
Many older adults will have low levels of serum of 25-hydroxyvitamin D levels (<20 ng/mL or 50 nmol/L). Older individuals at higher risk for vitamin D deficiency include those who are institutionalized, homebound, have limited sun exposure, obesity, dark skin, osteoporosis, or malabsorption. Monitoring of serum levels of 25-hydroxyvitamin D (25-OHD) is recommended for those at high risk, with the goal of achieving levels ≥30 ng/mL. Testing at three to four months following initiation of vitamin D supplements, if needed, should be done to assure that the target has been achieved. (See "Vitamin D deficiency in adults: Definition, clinical manifestations, and treatment".)
A combination of exercise and vitamin D supplementation is associated with increase in muscle mass and improvement in function among older adults living in a community [160,161]. Therefore, increased consumption of dietary sources of vitamin D should be encouraged in all older adults. In 2010, the Institute of Medicine (IOM) released a report on dietary intake requirements for calcium and vitamin D for normal healthy persons [162]. The Recommended Dietary Allowance (RDA) of vitamin D for adults through age 70 years is 600 IU, with the RDA increasing to 800 IU after age 71. (See "Overview of vitamin D", section on 'Requirements'.)
Vitamin D supplementation with cholecalciferol (vitamin D3) in doses of 600 to 800 IU daily is suggested for individuals with serum 25OHD level in the range of 20 to 30 ng/mL. Some individuals may need higher doses. Regimens for vitamin D supplementation for those with serum 25OHD levels <20 ng/mL are discussed separately. (See "Vitamin D deficiency in adults: Definition, clinical manifestations, and treatment", section on 'Dosing'.)
Inadequate intake of calcium — Calcium nutrition is strongly influenced by age. The efficiency of calcium absorption from the gastrointestinal tract decreases significantly after age 60. Individuals between 70 and 90 years of age absorb approximately one-third less calcium than do younger adults. Osteoporosis affects more than 10 million people in the United States and causes more than 1.5 million fractures within that population each year [163].
Given the impact of calcium deficiency on cortical bone loss, the adequate intake reference value for Ca for those >51 years of age was increased from 800 (1989 RDA) to 1200 mg/day. Food sources of calcium and available calcium supplements are shown in tables (table 3 and table 4).
Multivitamin supplementation — Whether multivitamin (MVI) supplementation should be routinely recommended to older adults remains a source of some controversy and confusion. Many older adults use MVI supplements. In the 1999 to 2000 National Health and Nutrition Examination Survey (NHANES), 35 percent of adults in the United States used multivitamin-multimineral supplements (MVM) and older adults were more likely than younger groups to use them (odds ratio [OR] 1.7, 95% CI 1.3-2.2) [164]. In a longitudinal cohort study of predominantly White older women, the use of dietary supplements increased significantly between 1986 and 2004 (from 63 to 85 percent of women reporting use of at least one supplement daily) [165].
MVM supplementation has been recommended for older adults who are more likely to have compromised nutritional status (such as those in the long-term care setting), to help achieve recommended intakes of certain micronutrients [166]. Available evidence, however, provides only weak support for this practice:
●In a study of 263 older adults attending senior centers, nutrient intake was estimated from dietary recalls and reported use of MVM supplementation [167]. Subjects who reported taking MVM were calculated to have improved intakes of vitamins E, D, B6, folic acid, and calcium but were likely to exceed the Tolerable Upper Limit for niacin, folic acid, and vitamin A.
●In a study of 4384 adults 51 years of age and older, supplements improved the nutrient intake of older adults. After accounting for the contribution of supplements, 80 percent or more of users met the estimated average requirement (EAR) for vitamins A, B6, B12, C, and E as well as for folate, iron, and zinc, but not for magnesium. However, some supplement users, particularly men, exceeded Tolerable Upper Intake Levels for iron and zinc and a small percentage of women exceeded the Tolerable Upper Intake Level for vitamin A [168].
●A few studies have suggested that MVM might reduce the incidence of infections, and upper respiratory tract infections in particular. In a systematic review of eight randomized trials of multivitamins and mineral supplements primarily involving older adults, three studies found that MVM reduced the number of days spent with infection by 17.5 (95% CI 11-24), but analysis of four studies showed no impact on the infection rate [169]. In an 18-month randomized trial involving 763 institutionalized older adults from 21 long-term care facilities, there was no statistically significant difference in the rate of infections in the supplement and placebo groups [170].
●In a cohort study of 38,772 older women followed for over 20 years with a mean age of 61.6 at baseline, supplementation with daily multivitamins was associated with a small increase in total mortality (hazard ratio [HR] 1.06, 95% CI 1.02-1.10) [165].
Therefore, routine supplementation with multivitamins and minerals is not indicated to reduce infections in frail older adults and is likely not beneficial unless it is clear that the older adult is not meeting his or her micronutrient needs due to low overall intake. The 2006 National Institutes of Health (NIH) Consensus Conference on the use of MVM found evidence insufficient to recommend for or against the use of MVMs to prevent chronic disease for the United States population in general [171].
SOCIETY GUIDELINE LINKS — Links to society and government-sponsored guidelines from selected countries and regions around the world are provided separately. (See "Society guideline links: Healthy diet in adults".)
INFORMATION FOR PATIENTS — UpToDate offers two types of patient education materials, "The Basics" and "Beyond the Basics." The Basics patient education pieces are written in plain language, at the 5th to 6th grade reading level, and they answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials. Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are written at the 10th to 12th grade reading level and are best for patients who want in-depth information and are comfortable with some medical jargon.
Here are the patient education articles that are relevant to this topic. We encourage you to print or e-mail these topics to your patients. (You can also locate patient education articles on a variety of subjects by searching on "patient info" and the keyword(s) of interest.)
●Basics topics (see "Patient education: Vitamin B12 deficiency and folate deficiency (The Basics)")
SUMMARY AND RECOMMENDATIONS
●Involuntary weight loss – The involuntary loss of more than 5 to 10 percent of an older person's usual weight during one year is an important clinical sign associated with increased risk for mortality. Weight loss should thus be met with concern and prompt a search for the cause. (See 'Introduction' above.)
●Causes of involuntary weight loss – Involuntary weight loss is generally related to one or a combination of four conditions: inadequate dietary intake, appetite loss (anorexia), muscle atrophy (sarcopenia), or inflammatory effects of disease (cachexia). (See 'Weight loss' above.)
•Inadequate dietary intake may relate to social, psychological, medical, and physiologic issues. Depression is the most prevalent associated condition in several studies, with cancer as the second most common cause. (See 'Inadequate dietary intake' above.)
•Proinflammatory cytokines are common in older adults and are particularly elevated in patients with cachexia. Sarcopenia is often related to a reduction in testosterone and estrogen and increase in insulin resistance. (See 'Cachexia' above and 'Sarcopenia' above.)
●Evaluation – Evaluation of weight loss should include serial weight measurements, dietary or appetite assessment, history, physical examination, and screening laboratory studies (complete blood count [CBC], chemistry profile, thyroid studies). Additional studies should be based on findings of the initial evaluation and may include upper gastrointestinal endoscopy for patients with early satiety or thoracic/abdominal/pelvic computed tomography (CT) scan for patients with unexplained ongoing weight loss. (See 'Evaluation of weight loss' above.)
●Treatment – Treatment should be directed at the underlying cause (ie, treatment for depression) as well as dietary modification. Nutritional restrictions should be lifted; patients with diabetes may do well with a regular diet and adequate monitoring. High-calorie foods should be provided.
We suggest providing oral nutritional supplementation for patients who do not regain weight with adjustments in meal preparation and diet (Grade 2B). We suggest not treating patients with appetite stimulants (megestrol acetate or dronabinol) due to marginal benefit and potential side effects (Grade 2B). (See 'Nutritional supplements' above and 'Appetite stimulants' above.)
●Overnutrition - Mortality risk in people over age 70 is not significantly impacted by an elevated body mass index (BMI) in the 25.0 to 29.9 range. Advice regarding weight loss for the overweight older person should be tailored to the individual, assessing the impact of excess weight on their quality of life, and should include the need for regular exercise. (See 'Overnutrition' above.)
●Micronutrient deficiencies
•Vitamin B12 deficiency – Vitamin B12 deficiency affects approximately 15 percent of people >60 years in the United States and most commonly relates to malabsorption of food-protein-B12 complexes. Oral B12 supplements, 1000 mcg daily, can usually correct B12 deficiency in the older adult. Daily intake of B12 10 to 15 mcg, by supplement or fortified products in the diet, is recommended for individuals >50 years. (See 'Vitamin B12 deficiency' above.)
•Vitamin D and calcium deficiency – Vitamin D deficiency is also common in the older population. Vitamin D supplements or fortified foods should supply 600 to 800 IU of vitamin D per day for older adults. Additionally, 1200 mg/day of elemental calcium should be provided daily. (See 'Vitamin D deficiency' above and 'Inadequate intake of calcium' above.)
