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Human Nutrition Chapter 16

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What are the 3 current hypotheses about the causes of aging?
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Usual aging
Usual aging: typical, expected part of aging...increasing fatness, decrease lean body mass and bone mass (affected by lifestyle choices and environment)
Successful aging
Declines that occur only because we grow older and not because of lifestyle choices, environment, and chronic disease
What causes aging?
-cells age and die
-after age 30, cell renewal occurs less than cell breakdown
-aging body can no longer meet physiological demands and function declines
What is reserve capacity?
-Organs maintain normal function with decreased cell number or activity for a while
-Severe demands on the body can exhaust reserve capacity (function decreases)
Compression of morbidity
Strive for the greatest number of healthy years, and fewest years of illness - compressing sickness to last few years of life
Life span vs. life expectancy
Life span: maximum number of years a human can possibly live (122 years)

Life expectancy: number of years an average person is expected to live (75 years for men, 81 years for women in the US)
-only 64 "healthy" years
-those who make 80, expect 7 to 10 more years
Factors that affect aging
Heredity
-living to old age tends to run in families
-females live longer than males

Lifestyle
-one's pattern of living (food choices, exercise patterns, substance use)
-improving lifestyle can slow progression of familial diseases in some cases (ex. premature heart disease)
-worsening lifestyle can offset the benefit of longevity genes
-follow mediterranean diet linked to lowest rates of chronic disease

Environment
-income, education level, health care, shelter, psychosocial factors
-being able to purchase nutritious foods, quality health care, safe housing
-education helps with decision making
Nutrients that should be limited in the diets of most American adults
-Sodium: intakes in excess lead to hypertension, osteoporosis, tax on kidneys
Nutrients that are commonly lacking in the diets of adults
-calcium and vitamin D: decreased intake and decreased absorption; when low risk of osteoporosis

-iron: blood loss, ulcers, hemorrhoids, decreased absorption

-zinc: decreased absorption, deficiency leads to decreased taste sensation, impaired immunity and wound healing, mental lethargy

-magnesium: limited intake, deficiency leads to bone loss, weakness, mental confusion

-folate, B-12, B-6: required to clear homocysteine from blood to reduce risk of cardiovascular disease, stroke, bone fracture, and neurological decline; B-12 absorption declines as acid production declines with aging

-vitamin E: intake usually short of recommendation, inadequate intake decreases antioxidants in body and increases risk of cell damage
Sarcopenia
-loss of muscle mass, muscles shrink and can be lost, muscles lose elasticity with added fat and collagen

-sarcopenic obesity: loss of muscle mass accompanied by gains in fat mass
Three ways aging affects the processes of digestion, absorption, and utilization of nutrients
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Physiological changes of aging
DECREASED: appetite, sense of taste and smell, chewing/swallowing ability, sense of thirst, stomach acidity, bowel function, lactase production, liver function, insulin function, kidney function, immune function, lung function, vision, lean tissue, cardiovascular function, bone mass, mental function

INCREASED: fat stores
combat loss of appetite
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combat decreased sense of taste and smell
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combat decreased chewing/swallowing ability
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combat decreased sense of thirst
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combat decreased stomach acidity
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combat decreased bowel function
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combat decreased lactase production
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combat decreased liver function
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combat decreased insulin function
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combat decreased kidney function
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combat decreased immune function
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combat decreased lung function
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combat decreased vision
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combat decreased lean tissue
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combat decreased cardiovascular function
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combat decreased bone mass
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combat decreased mental function
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combat increased fat stores
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2008 Physical Activity Guidelines for Older Adults
Engage in moderate-intensity aerobic exercise for at least 150 minutes/week
OR vigorous-intensity aerobic exercise for 75 minutes/week
OR an equivalent combination of the above recommendations
GOAL: weight management, preservation of bone mass, prevention of chronic diseases

Preform strength training exercises 2-3 times per week: focus on large muscle groups and enhance grip strength
GOAL: maintain lean tissue and basal metabolic rate

Include exercises that improve balance if there is a risk of falling; incorporate stretching exercises into strength or aerobic exercises 2 days/week
GOAL: improve balance and daily functioning
Changes in dentition that occur with aging
About 25% of older adults have no natural teeth, many more missing some teeth

-worse in low-income populations
-avoid harder-to-chew foods
-miss out on protein, iron, zinc, potassium, and fiber
-pureed foods sometimes necessary
Consequences of decreased HCI production and intrinsic factor in stomach
impaired absorption of iron, calcium, zinc, and B-12
decreased production of some digestive enzymes (ex. lactase)
Digestive system concerns of adulthood and how to address them
Main intestinal problem: Constipation
-increase fiber, fluid
-exercise
-fiber supplements may be needed
-some medications cause constipation

Gallbladder and pancreas function declines
-gallstones and gall bladder diseases can impair fat absorption
-high blood glucose signals pancreatic dysfunction
How perceptions of taste and smell change as we age and how it can affect nutritional status
gradual loss of nerve cells
-decreased sense of taste and smell
-impaired neuromuscular coordination, reasoning, memory
Nervous system changes
Hearing and vision declines
-curtails social and physical activity

Neuromuscular coordination losses
-ability to prepare meals declines
-opening packages becomes challenging
Immunity as we age
Immune system operates less effectively

Require protein, folate and vitamins A, D, and E, iron, zinc to maximize immune system function

Overnutrition harmful to immune system
Changes in insulin sensitivity and the effect it can have on health
Rate of hormone synthesis and release can slow

Decreases in insulin production/insulin sensitivity --> results in high blood glucose that takes longer to return to normal after a meal
How to prevent insulin resistance
maintain healthy weight, exercise regularly, eat a diet low in fat, high in fiber, and avoid foods with a high glycemic index
How medication and supplement use can affect health
may interact with nutrients, may affect appetite, sense of taste and smell, some alter nutrient needs
How depression influences nutritional status
-poor appetite
-poor food choices
-misuse of medication
-disability (weakness)
-mental confusion
-poor nutrition
-obesity for some
How limited financial resources can affect nutritional status
money impacts types/amounts of food one eats
-do not eat enough food or enough nutrients to meet nutritional needs
-nutritional and health status declines
warning signs of undernutrition: DETERMINE
Disease
Eating Poorly
Tooth loss or mouth pain
Economic hardship
Reduced social contact and interaction
Multiple medications
Involuntary weight loss or gain
Need for assistance with self-care
Elder at advanced stage
Eating well for an older, single man
1. eat regularly: small, frequent meals
2. keep easy-to-prepare foods on hand
3. have a treat occasionally
4. eat with friends, relatives, or at a senior center
5. stay physically active
Possible nutritional resources for an older adult with limited financial means
Older Americans Act Nutrition Program: congregate meal programs provide lunch at a central location, meals-on-wheels deliver to home-bound adults

Federal commodity distribution: low-income elderly, food stamps (SNAP)

Food cooperatives and religious organizations
Binge drinking
Men: 5+ drinks in a row
Women: 4+ drinks in a row
What counts as a serving of alcohol
12 oz beer or wine cooler
5 oz wine
3 oz sherry or liqueur
1.5 oz 80-proof distilled spirits
Alcohol absorption
-requires no digestion

-absorbed rapidly via simple diffusion in intestines

-depends on rate of stomach emptying

-rate of absorption: fastest to slowest
wine --> distilled spirits --> beer
Alcohol metabolism
depends on gender, race, size, food, physical condition, alcohol content

90-98% is metabolized, mostly in liver

enzymes: alcohol dehydrogenase and acetaldehyde dehydrogenase

alcohol CANNOT BE STORED