Aging is a process that occurs throughout life. Its impact, however, is often ignored until adulthood. Progressive changes in body composition, sensory perception, functional status and physiologic functioning occur at all ages. The rate of change is strongly influenced by the genetic background and life experiences of the individual .
Older adults display wide individual variations in aging processes and thus in nutritional needs and concerns. Maximizing and maintaining adult potential becomes the major health care objective. The nutritional care goal is to provide education and support to achieve this objective as decreases in metabolic needs, declining activity levels, illness, infirmity, economic hardship, loss of social support systems, and other variables mandate adjustments in food intake.
Each older adult should be viewed as a unique individual. Chronological age and functional capacity do not directly correlate. Diversity increases with age . Provision of quality nutritional care requires the regular, systematic, longitudinal assessment of each older individual as well as a nutritional care plan based on specific needs identified. The least restrictive regimen possible should be implemented.
Dietary Considerations for the Older Adult
The DRIs divide the adult population older than 50 years into 2 life-stage groups: 51 through 70 years and older than 70 years . DRIs for calcium and related nutrients (phosphorus, magnesium, vitamin D, and fluoride), and for folate and B vitamins (thiamin, riboflavin, niacin, vitamins B6 and B12, panthothenic acid, biotin, and choline) have been established .
Taste and smell dysfunction tends to begin at around 60 years of age and becomes more severe in persons over 70. Two thirds of persons over 75 years of age are edentulous. More sweet flavorings or salty foods may be required to satisfy the appetite of elderly individuals.
Energy and Nutrient Considerations
Basal metabolic rate (BMR) decreases 2% with each decade of life; lean body mass declines 6% with each decade and is usually replaced with fat. As BMR decreases with advancing age and physical activity is reduced, energy needs decrease. The current DRIs suggest an average gradual reduction of kilocalories after the age of 19 years by deducting 10 kcal/day for males, and 7 kcal/day for females for each year of age above 19 years. For a 51 year old male, this would equate to a 320 kilocalorie reduction from the baseline DRI . Refer to Section IA
The 2002 DRIs to recommend that the RDA for protein should be 0.8 g/kg daily for adults of all ages. However, other studies recommend protein be increased to 1.0 to 1.25 g/kg daily or 12% to 14% of total energy intake for the elderly.
Metabolic and physical changes that affect the status of vitamin B6, B12, and folic acid may alter behavior and general health, whereas adequate intake of these nutrients prevents some decline in cognitive function associated with aging . Deficiencies of these nutrients, along with inadequate intake of vitamin C and riboflavin, may result in poor memory . Immune function affected by nutritional status may be improved by an increased intake or supplementation of protein, vitamins B6 and E, and zinc . It is recommended that persons 51 years of age and older consume foods fortified with vitamin B12 or take a supplement containing vitamin B12, as 10% to 30% of older adults have protein-bound vitamin B12 malabsorption .
Vitamin D levels may be reduced in the elderly even with adequate exposure to the sunlight, and deficiency may be exacerbated by homebound status, use of sun block, poor dietary intake, decreased capabilities to synthesize cholecalciferol in the skin, and decreased number of gastrointestinal receptors . Decreased capacity to absorb calcium is also observed because of reduced estrogen levels, low circulating 25 (OH)D, partial intestinal resistance to 1,25(OH)D, and impaired renal conversion of 25(OH)D to 1,25(OH)2D . Supplementation of 1.0 to 1.7 g calcium along with vitamin D (400 IU) is shown to reduce the incidence of age-related hip fractures and decrease the rate of age-related bone loss .
Dehydration is a major problem for the elderly. Water intake needs are the same for the young and the old, but the elderly are prone to inadequate water intake. Frequently, diseases will reduce the ability to recognize thirst, create an inability to express thirst, or decrease access to water. Even healthy elderly persons appear to have reduced thirst in response to fluid deprivation. Fear of incontinence and difficulty making trips to the toilet, due to arthritic pain or other immobility, may also interfere with adequate fluid consumption. The elderly should be encouraged to ingest about 2 L of fluid per day or 30 cc/kg body weight.
Contributors to Poor Nutritional Status in the Elderly
A variety of factors may contribute to poor nutritional status as individuals age . Table A-4 lists some of the factors frequently identified as potential causes of malnutrition. These must be kept in mind when evaluating nutritional status and when developing a care plan to prevent, delay, or correct problems identified. For some conditions, cure is not possible but ameliorative or palliative nutritional interventions are often indicated . Improvement in the quality of life will frequently ensue.
