Chapter 18.docx

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10 Apr 2012
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Chapter 18: Nutrition and Older Adults
Key Nutrition Concepts
1. Enjoying a varied diet contributes to mental and physical well-being
2. The population of “older adults” is heterogeneous; generalizations about nutrition and
health status are unlikely to fit many individuals
3. Diseases and disabilities are not inevitable consequences of aging
4. Functional status is more indicative of health in older adults than is chronological age
5. Body-composition changes that occur with aging can alter lifestyle; these changes may
modify nutritional needs
Introduction
- A positive outlook toward one’s own old age is associated with increased longevity
- The leading causes of death for people aged 60 and older are heart disease, cancer, and
stroke; these three and diabetes mellitus have nutritional risk factors
- Older adults feel that good nutrition and exercise are the most important health habits
they can maintain in order to avoid losing autonomy and independence
- Older adults can meet their decreasing energy requirements by choosing more nutrient-
dense foods eating adequate amounts of vegetables, fruits, and whole grains, keeping fats
in balance, and drinking alcohol only in moderation will reduce risks of contracting
diseases
- Good health habits help to delay morality and achieve compression of morbidity in older
populations
- Compression of morbidity: shortening the period of illness and decreased functional
capabilities at the end of life
- What Counts as Old Depends On Who is Counting
o Chronological age is a simple place to begin to understand someone’s nutritional
health. However, functional status, a description of how well one can accomplish
the desired tasks of daily living, is more indicative of health than chronological
age
- Food Matters: Nutrition Contributes to a Long and Healthy Life
o The cumulative effects of lifelong dietary habits determine nutritional status in
old age
o Good nutrition throughout life contributes to optimal growth, to appropriate
weight, and to nutrient levels in blood and other tissues that boost immunity and
provide disease resistance
o The CDC suggests that longevity depends 19% on genetics, 10% on access to
high-quality health care, 20% on environmental factors, and 51% on lifestyle
factors
o The role of food and nutrition often changes during aging
o Besides reducing risk of disease and delaying death, diet contributes to wellness
meaning having the energy and ability to do the things one wants to do and to feel
in control of one’s life
A Picture of the Aging Population: Vital Statistics
- Global Population Trends: Life Expectancy and Life Span
o Life expectancy at birth in the U.S. is 78 years compared to 47 years in 1900
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o At age 65, an individual can except to live another 19 years, and someone
reaching age 85 can expect to live another seven years
o Other contributors to life expectancy estimates include rates of childhood
morality, infectious and chronic diseases, and death from violence and accidents
o Since the early 1900s, immunizations and other risk reduction measures,
treatment of disease, decreased infant and childhood morality rates, and clean
water and sage food have increased average life expectancies, which are getting
closer to the potential human life span
o See table 18.1 for Ten countries leading to longest life expectancy at birth
o Centenarian: person who reaches age 100 or more
o Super-centenarian: person who has reached aged 110 or more, validated
o Senescene: old age
- Nutrition: A Component of Health Objectives for the Older Adult Population
o See table 18.2 for dietary goals related to disease prevention and to health
promotion for older adults s
o Body
Theories of Aging
- Genetics are through to account for up to one third of longevity
- Environmental factors influence expression of the genetic code by exacerbating or
attenuating certain traits
- Body composition demonstrates reactions between genes and environment
- Theories of aging can be examined from two perspectives: (1) programmed aging
theories and (2) “wear and tear” theories
- Caloric restriction is an intervention that incorporates aspects of several aging theories to
manipulate life span and morbidity
- Programmed Aging
o Hayflick’s Theory of Limited Cell Replication
Hayflick proposed that all cells contain a genetic code that directs them to
divide a certain number of times during their life span
After cells divide according to their programmed limit, and barring disease
or accident, cells begin to die
Hayflick’s theory is difficult to prove in humans because we die from age-
associated chronic disease more often than from old age itself
o Molecular Clock Theory
Telomeres that cap the ends of chromosomes act to mark time, becoming a
bit shorter with each cell division
Eventually loss of telomeres stops the ability of chromosomes to replicate
Loss of chromosomal replication may produce signs of aging because
new cells cannot be formed, and the function of existing cells declines
with time
- Wear-and-tear Theories of Aging
Built on the concept that things wear out with use
Mistakes in the replication of cells or build-up of damaging by-
productions from biological processes eventually destroy the organism
Cyotoxicity results when damaged cell components accumulate and
become toxic to health cells
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Glucose binding to proteins leads to accumulation of AGEs; cross linking
between cells stiffens collagen fibres, including those in tendons,
ligaments, blood vessels, and kidneys
The accumulation of damaged cells and waste by products leads to
declining function and aging
o Free-Radical or Oxidative Stress Theory
One cause of aging is thought to be oxidative stress due to the build-up of
reactive oxygen compounds
Unstable oxygen, formed normally during metabolism can also initiate
reactions that break down cell membranes and damage cells needed to
keep the immune system intact
Exposure to oxidizing agents is increased by smoking, ozone, solar
radiation, and environmental pollutants
Unstable oxygen compounds are neutralized when they combine with an
antioxidant
The body produces antioxidant enzymes but part of our need is met from
the diet
Dietary antioxidants include beta-carotene, lycopene, flavinoids, lutein,
zeaxanthin, resveratrol, and isoflavones
o Rate-of-living Theory
Suggests that faster living results in faster aging
Fast paced living shortens life span, whereas living more slowly leads to a
longer life
- Calorie Restriction to Increase Longevity
o Animal studies show that an energy restricted diet that meets micronutrient needs
can prolong healthy life
o Experimental findings in small animals have led some individuals to personally
adopt very low calorie diets
o From an ecological view, France and Japan have lower caloric intake than do
people in the US and people in both of those counties also live longer
Physiological Changes
- Normal aging is associated with body-composition shifts that most often lead to loss of
physical resilience
- Healthy aging is associated with continuing psychological, personal, moral cognitive, and
spiritual development
- Body-Composition Changes
o Lean Body Mass (LBM) and Fat
Of all physiologic changes that occur during aging, the biggest effect on
nutritional status is due to the shifts in the musculoskeletal system, which
loses up to 15% of fat free mass
On average, there is a decline in lean body mass of 2% to 3% per decade
from age 30 to 70, including loss of muscle (sarcopenia) beginning around
age 40, even when weight is stable
During this time, body fat increases, especially in the visceral region
Losses of fat free mass leave older people with lower mineral, muscle, and
water reserves to cal upon when needed
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