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Improvements in nutrition, general health, and life expectancy are changing global demographics and the cultural, social, and economic foundations of society. Americans are continuing to live longer than previous generations. The older population (persons 65 years or older) represented 13.7% of the US population in 2012, about 1 in every 7 Americans. This population is expec- ted to grow to be 21% of the population by 2040. In 2050, it is estimated that 4.3% of the population of the United States will be older than age 85 years (1). More than 95% of Americans older than 65 years live in the community while less than 5% reside in institutional facilities (2). However, the percentage increases dra- matically with age, ranging (in 2012) from 1% for persons 65 to 75 years to 3% for persons 75 to 84 years and 10% for persons over 85 years. About 28% of non- institutionalized older adults live alone (3). This upcoming group of older adults will be more ethnically diverse and better educated than prior generations and will demand a greater involvement in medical decision making (4). The implications for the health care system regarding demographic and care provision shifts of this magnitude are just beginning to be realized. It is imper- ative that societies maximize not only life span, but also the health of older adults so that these individuals can maintain full function as long as possible. Providers will be held increasingly accountable for the services rendered and outcomes attained. Person- driven, team-provided, coordinated care with a focus on wellness, prevention, and self-management of chronic disease will become the norm. Although today’s older Americans are more pros- perous than prior generations (1), recent downturns in the US and global economy may result in considerably smaller than anticipated economic gains and fewer total financial resources upon which older Americans can rely. The prospect of sustained cuts in social spend- ing for health care will increase the vulnerability of the older adult and those with chronic illness (5,6).

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Nutrition in Older Adults: An Overview

Measures such as quality-adjusted life-years (7) will increasingly be applied when determining health care coverage. Improving the health of our older population by encouraging the adoption of healthy lifestyles and food intakes to optimize nutritional status will become an even more important component of cost-effective, efficient, person-driven care.

Many diseases or conditions that would be consid- ered abnormal or even alarming in younger adult popu- lations are viewed as a part of the “normal aging pro cess” in those 65 years or older. This perception will be adjusted as the number of studies that investi- gate the effects of aging on various body systems and processes increases and the impact of confounding factors such as nutritional status and physical activity is recognized.

This discussion will summarize what are currently believed to be clinically important, age-related changes in physiology and function and their impact on the nutritional needs of older adults. Generally speaking, aging is associated with a decline in the function of most organs and tissues. However, the extent to which physiological decline occurs varies greatly.

FOOD INTAKE

Food intake tends to decline as age advances, especially among the very old and the frail elderly living in insti- tutional settings. Older people tend to be less hungry/ more full before meals, to eat smaller meals, to eat more slowly, to eat fewer snacks, and to feel fuller after meals than do younger adults (8). However, data from the National Health and Nutrition Examination Survey (NHANES) indicate that between 1971 and 2013, average total energy consumption among US adults increased 22% in women (from 1,542 to 1,886 kcal/d) and 10% in men (from 2,450 to 2,693 kcal/d) (9). A higher percentage of older Americans are over- weight/obese than ever before. In 2009 and 2010, 45% of women ages 65 to 74 and 30% of women age 75 and