Life Cycle Nutrition: The Adult Years Chapter 16

Life Expectancy: 1900 vs. 1980 How long can you expect to be healthy? Avg life expectancy: 78 yrs Avg healthy life expectancy: 69 yrs How long can you expect to be healthy?

What Causes Aging? As organisms become older, number of cells decreases and function of remaining cells declines As tissues and organs lose cells, ability of organism to maintain homeostasis decreases Loss of cells occurs throughout life but is not felt for a long time, as organisms begin with reserve capacity Reserve capacity diminishes as we age, and we begin to feel the effects of aging Reserve capacity: amt of functional capacity an organ has above and beyond what is needed to sustain life Cell loss occurs due to -programmed cell death (only divide a certain # of times before kaput) -wear and tear (errors in DNA, high BG, free radical damage)

What Affects the Rate of Aging? Genes: efficiency with which cells are maintained and repaired--only one factor! Can be diminished by influences from environment and lifestyle Environment: can contain factors that damage cells Lifestyle: can either support longevity or speed aging

Nutrient Needs in Adulthood Energy needs typically decline with age Decreased BMR Protein, fat, and CHO needs remain about the same Protein: 0.8 g/kg body weight Fat: 20-35% of kcals Avoid trans-fat, get ample EFAs CHO: 45-65% of kcals Fiber important for prevention of GI issues and chronic illness Water: needs remain the same as we age More challenging to meet these needs in older age Decreased sense of thirst Kidneys decline in function, increasing losses Micronutrients Recommendations remain the same for most as we age Increases in recommendations for B6, calcium, vitamin D, and magnesium Decrease in iron recommendation for women past menopause Energy needs: when all other factors are unchanged, energy needs decline; drops even more if PA decreases BMR drop: 2-3% per decade after 20 Fiber: prevention of (GI) constipation, hemorrhoids, diverticulosis and (chronic) DM, CVD, obesity. Water losses in older age: Medications can increase losses; also, if incontinence is an issue, older adults may restrict water -problems: symptoms of dehydration; impairs organ function; contributes to constipation

Malnutrition in elderly populations: decreased intake plus decreased absorptive capacity Sensory decline begins around 60-->decreased palatability of food -Lower production of saliva contributes to issue; also makes it more difficult to swallow

Consequences of Malnutrition

Federal Nutrition Screening Initiative program developed this checklist for evaluating elderly populations for malnutrition -physiological, medical, and socioeconomic situations all contribute

Nutritional Strategies in Older Age Maximize nutrient density Nutritional supplements may be useful Decreased overall intake Decreased absorptive capacity Take care to avoid excesses Check with healthcare provider to rule out drug-nutrient interactions Well-balanced MVI; avoid megadoses unless prescribed by health care professional

Changes in Body Composition with Age Sarcopenia: loss of muscle mass and strength -affects both skeletal muscle used to move body and heart and respiratory muscles needed to move blood around body and breathe -can lead to state of physical frailty-->general weakness, impaired mobility and balance, poor endurance, susceptibility to falls and fractures -In adults over 85, loss of muscle strength is major determining factor in ability to live independently -Changes in muscle protein synthesis and hormones are partially to blame, but lack of PA is also an important contributor

Importance of Physical Activity Extends years of active, independent life Reduces disabilities Improves overall quality of life and health Bone strength Muscle mass Cardiorespiratory function Increases discretionary kcalorie allowance