Geriatric Nutrition Health Article

Definition

Geriatric nutrition applies nutrition principles to delay effects of aging and disease, to aid in the management of the physical, psychological, and psychosocial changes commonly associated with growing old.

Purpose

The number of people over 65 years of age jumped from 4% of the U.S. population in 1900 to 13% in 1990, and is expected to reach 20% in 2030, due primarily to advances in health care. "Elderly" was once defined as being age 65 or above, but the growing number of active and healthy older people has caused that definition to expand to "young old" (65 to 75), "old old" (75 to 85), and "oldest old" (85 and beyond). The over-85 age group is the one that is growing most rapidly.

The cornerstone of geriatric nutrition is a well-balanced diet. This provides optimal nutrition to help delay the leading causes of death: heart disease, cancer, and stroke. In addition, ongoing research indicates that dietary habits, such as restricting one's calorie intake and consuming antioxidants, may increase longevity.

Physiological changes

With age comes many physical changes. Once the body reaches physiologic maturity, the rate of degenerative change exceeds the rate of cell regeneration. However, people age at different rates, so the elderly population is not a homogeneous group; there is great variability among individuals.

The following are typical physiologic changes that can affect nutritional status:

• Body composition changes as fat replaces muscle, in a process called sarcopenia. Research shows that exercise, particularly weight training, slows down this process. Because of the decrease in lean body mass, basal metabolic rate (BMR) declines about 5% per decade during adulthood. Total caloric needs drop, and lowered protein reserves slow the body's ability to respond to injury or surgery. Body water decreases along with the decline in lean body mass.
• Gastrointestinal (GI) changes include a reduction in digestion and absorption. Digestive hormones and enzymes decrease, the intestinal mucosa deteriorates, and the gastric emptying time increases. As a result, two conditions are more likely: pernicious anemia and constipation. Pernicious anemia may result because of hypochlorhydria, which decreases vitamin B₁₂ absorption and affects approximately one third of older Americans. Constipation, despite considerable laxative use among older people, may result from slower GI motility, inadequate fluid intake, or physical inactivity.
• Musculoskeletal changes occur. A progressive drop in bone mass starts when people are in their 30s or 40s; this accelerates for women during menopause, making the skeleton more vulnerable to fractures or osteoporosis. Adequate intake of calcium and vitamin D helps to retain bone.
• Geriatric nutrition must take into account sensory and oral changes. Decreases in all the senses, particularly in the taste buds that affect perception of salty and sweet tastes, may affect appetite. Xerostomia, lack of salivation, affects more than 70% of the elderly. Also, denture wearers chew less efficiently than those with natural teeth.
• Other organ changes may occur. Insulin secretion is decreased, which can lead to carbohydrate intolerance, and renal function deteriorates in the 40s for some people.
• Cardiovascular changes may occur. Reduced sodium intakes become important, as blood pressure increases in women over age 80 (but, interestingly, it declines in older men). Serum cholesterol levels peak for men at age 60 but continue to rise in women until age 70.
• Immunocompetence decreases with age. The lower immune function means less ability to fight infections and malignancies. Vitamin E, zinc, and some other supplements may increase immune function.

Psychosocial changes

A number of changes may occur in the aging person's social and psychological status, potentially affecting appetite and nutrition status. These include:

• Depression, the most common cause of unexplained weight loss in older adults, occurs in approximately 15% of adults over age 65, with a much higher incidence in those living in extended-care facilities.
• Memory impairment caused by various types of dementia, Alzheimer's disease, or other neurological diseases rises dramatically, with half of all persons over age 85 affected. Weight loss and improper nutrition are potential problems.
• Alcohol abuse is often unreported, especially since approximately one third of alcoholics age 65 years or older begin drinking later in life. Excessive alcohol intake (over 15% of total calories) increases morbidity and mortality, and leads to both physical and psychosocial problems.
• Social isolation becomes more common because of declining income, health problems, loss of spouse or friends, and assistance needs. All of these may affect appetite and possibly nutritional status.