Chapter 1 Nutrition in Older Adults: An Overview

(34). The contribution of medications to this problem must be fully explored. Certain analgesics (especially narcotics), antidepressants, antihistamines, calcium channel blockers, anti-parkinsonism drugs, and high doses of iron and calcium contribute to constipation. Other factors that may increase the chances of consti- pation include mechanical obstructions, metabolic dis- orders, neurological diseases, dehydration, and inadequate fiber. Lifestyle changes such as increased fluid and fiber intake, encouragement to toilet after eating, and regular exercise are cornerstones of treat- ment but are inconsistently utilized. Unfortunately, laxatives continue to be used daily by 10% to 18% of community-dwelling older adults and 74% of nursing facility residents (34), in part because of limited fluid and dietary fiber intake, decreased activity, fear of incontinence, and, often, poor dietary choices. Fiber supplements should not be used in people who are immobile or who are consis- tently unable to consume an adequate amount of fluid (35). Management of diarrhea also requires careful attention to hydration as well as to electrolyte replace- ment and infection control to decrease its incidence and recurrence (36).

Inflammation

“Inflammation is increasingly identified as an import- ant underlying factor that increases risk for malnutri- tion and that may contribute to suboptimal response to nutrition intervention and increased risk of mortality” (37). Inflammatory processes and vascular dysfunction appear to be associated with the pathogenesis of age-associated neurodegenerative diseases, such as age-associated memory loss, mild cognitive impair- ment, Parkinson’s disease, and Alzheimer’s disease (38,39). Selected phospholipids, L-carnitine, omega-3 fatty acids, omega-6 essential fatty acids, vitamin E, citicoline, folic acid, vitamin B-12, and thiamin may exert a protective effect on age-related behavioral defi- cits, possibly through their role as antioxidants or mod- ulators of cellular function. Diets rich in these nutrients (38,39) and supplements (40), especially low-dose sup- plements (38,39) for those unable to consume adequate diets, may be considered. Botanicals, particularly those rich in polyphenols that exhibit anti-inflammatory and/ or antioxidant properties, may have potential for the prevention/treatment of cognitive impairment (40). In many cases, it is not possible to diagnose nutri- tional deficiency by clinical history and physical exam alone. “Infection is the primary cause of death in one- third of individuals aged 65 years and older and is a contributor to death for many others. Infection also has a marked impact on morbidity in older adults, exacer- bating underlying illnesses and initiating functional

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decline.” However, increased rates of infection in the respiratory, urinary, and genital tracts and impaired cognition, demonstrated by deficits in short-term memory, reduced ability for abstract tasks, and limited attention span, suggest that subtle, subclinical deficits may be present. Impaired immune function has also been observed at excessive levels of nutrient intake (41). Thus, recommendations regarding supplements of single nutrients or nutrient combinations, with few exceptions, are difficult to make at this time. Effects of aging on the immune system are not uniform among individuals. In the future, it is anticipated that testing will be able to identify key biomarkers and establish simple laboratory tests to define each person’s aging profile. Even so, whatever standard of care is ulti- mately adopted for stimulating immunity, the emphasis should not necessarily be placed on increasing life span. Rather, the aim should be to increase health span, defined as years of healthy living (42).

BODY COMPOSITION AND BODY MASS INDEX

Up to 10% of community-dwelling and homebound older adults, between 23% and 56% of hospitalized older adults, and up to 21% of nursing home older adults are diagnosed with incidence of protein-energy malnutrition (43). Protein-energy malnutrition with or without catabolic diseases will lead to loss of lean body mass, which can result in weakness, gait and balance disorders, falls and fractures, functional decline, insulin insensitivity, and an increase in morbidity and mortal- ity (43,44).

Body weight and lean body mass (LBM) decrease as age advances. Older adults exhibit an increase in the percentage of body fat and greater visceral fat stores, even though total weight declines (8). The standard definitions for optimal body mass index (BMI) for US adults (greater than 18.5 to less than 25) are not supported by the amount of evidence in populations 65 years and older. Most evidence suggests that the BMI associ- ated with maximum life expectancy increases with age and varies by race (45-47). According to the Centers for Medicare & Medicaid Services (CMS) standards for universal weight screening, a weight falling within the range of greater than 23 to less than 30 kg/m2

is acceptable for those 65 years and

older. Those whose weight falls outside of these norms should have a care plan identified to address the underweight or overweight. Weight should be measured every six months at minimum (48). Another measure of LBM is the creatinine height index (CHI), which has been used to assess nutritional status in older adults. Creatinine is formed irreversibly