NUTR 337- young adulthood and elderly part 1

• Achievement of maximum height
• Formation of peak bone mass

3rd decade

Maximal strength, endurance and agility?

Muscle mass increases until 3rd decade, then declines gradually

Average body weight increases until 7th decade in both sexes

No adjustment to decreased energy expenditure by decreasing caloric intake

physical activity

• Greatly increased risk of diabetes, HTN, CVD
• Increased %fat and decreased LBM

>1/3

• Shift in natural composition of the diet, which lead to increased intake of animal fat and decreased complex CHO and fiber
• Link with cancer, CHD, obesity and dental caries

Increased risk of disease

Associated with protection against a variety of diseases

• Diets high in saturated at, alcohol, Na, sugar and low in fiber
• Lifestyles that include smoking, little exercise and high stress

• Delay onset of aging and chronic disease
• Increase optimal function for longer period of time
• Increase quality of life in the present

• Eat a variety of foods
• choose most of what you eat from plant sources
• Eat 5 or more servings of fruits and vegetables each day
• Eat 6 or more servings of bread, pasta, and cereal grains each day
• Eat high-fat foods sparingly, especially those from animal sources
• Keep your intake of simple sugars to a minimum

Consume a balanced diet with emphasis on antioxidant-rich fruits and vegetables and whole grains

• Increased from 45 years at the turn of the century to 75 years in 1990
• in 15 years, the mean life expectancy will be 77 (males) and 84 (females)

50%

• Associated with aging process that is accelerated by disease and lifestyle factors
• Poor exercise habits and alcohol and tobacco abuse

• Associated with age related changes that are not increased due to lifestyle or disease
• Sound nutrition habits, exercise regularly and habe good blood pressure control

CHD, cancer, infection

• Nutrition may greatly influence immune function in elderly
• Malnutrition is the best predictor of total number of visits to the hospital or a physician

Elderly who took multivitamin and mineral supplements showed 1/2 infection rate

• decrease incidence of cataracts
• Improve mental ability
• Prevent some forms of dimentia

• Decreases dementia like symptoms
• Increases mental functioning

Better cognitive performance among elderly

• Due to both decreased physical activity and hormonal changes
• Decreased growth hormone production with age
• Decreased estrogen (females) and testosterone (males) leads to changes in bone mineral density
• Decreased testosterone: contributes to decreased muscle mass (inability to maintain protein stores)

• Physically active older men have lower % body fat than inactive young men
• Physical training in elderly increases muscle strength and LBM which leads to better mobility even among 90 year olds

CVD due to heart conditions and HTN

• Cancer
• 25% of females and 20% of males

40% of elderly after age 80

• Drugs, UV light, mutagens and radiation
• Cause a decrease in DNA repair activity
• Accumulation of damage from environmental stresses which damage and kill cells
• Errors during copying of DNA accumulate which leads to a change in protein synthesis which leads to decreased cell functioning

• Changes in the functioning of anterior pituitary leads to altering of hormonal balance which leads to adverse altering of normal metabolism
• Decreased growth hormone leads to increased adipose tissue and decreased LBM
• Decreased testosterone leads to a decreased ability to maintain protein stores and bone mass
• Decreased estrogen leads to a decreased ability to maintain bone mass

Glycation causes cross-linking between protein molecules

• Environmental exposures via radiation, natural body processes
• Causes macromolecular damage

• Specific genes that predetermine lifespan
• Telomeres: end of chromosomes; decrease with age

• GI, renal, liver functioning lead to increased risk of malnutrition
• Malnutrition worsens disease and increases likelihood of adverse drug interactions

• Anorexic effect of physical trauma
• Decreased ability to prepare food

• Eating poorly
• Economic hardship
• Reduced social contact

• Inhibiting their absorption
• Binding to them in the body to make them unavailable to the tissues
• Enhancing their excretion
• Causing an inhibition of their activation in the body to an active form

Cholesterol lowering drugs that are bile acid sequestrants (cholestyramine) prevent reabsorption of bile salts which lead to a decrease in fat soluble vitamin absorption

Destroy intestinal mucosa, villi and microvilli and inhibit brush border enzymes

• Inhibit lactase enzyme
• Directly damage the gut and decrease fat and micronutrient absorption

• Dissolve fat and fat soluble vitamins which allows them to be excreted in feces
• Decrease in transit time from use of laxatives and mineral oil leads to a decrease in nutrient absorption in terms of Ca and K losses

Anti-ulcer drugs (cimetidine) decrease HCl production which leads to a decreased amount of B12 release from foods which means less B12 is available for binding with intrinsic factor for absorption

Loop diuretics (furosemide) for blood pressure control lead to an increase in renal excretion of thiamin and can cause cardiac abnormalities (excessive use)

Cause potassium depletion and lead to an increased risk of cardiac arrythmias

Binds to folate binding sites on plasma protein normally involved with blood transport of the vitamin (albumin) which leads to increased urinary excretion of folate

3 or more unformed bowel actions in 24 hours

• Acute: an episode of diarrhea lasting < 2 weeks
• Chronic: diarrhea lasting 3-6 weeks

Frequency and severity of dehydration and electrolyte loss (may cause death)

• Temporary alteration of colonic bacteria
• Damage to small intestinal mucosa
• Most often mild and self-limiting
• Some cause osmotic diarrhea (alteration of bacterial flora which leads to a decrease in colonic fermentation of CHOs which act as osmotic agents)

• Antacids containing magnesium trisillicate or Mg hydroxide
• Drugs to treat peptic ulcer (cimetidine)

Damage immature epithelial cells, compromising their absorptive function

• Polypharmacy, sel-medication, noncompliance in regard to usage
• Inappropriate drug prescribing

Replacement of old bone with newly synthesized bone tissue

Osteoblasts

• Dissolve bone mineral with acids and digest bone matrix
• With recruitment of phagocytes to remove the protein

• Reduced bone of normal composition
• Bone density <2.5SD below young people

• Bone losses are accelerated in the early postmenopausal period
• Onset 50-70 years of age

• Higher peak bone mass
• Ca supplementation in pubertal growth spurt

Can lose up to 20% of bone mass in 5-7 years after menopause

• Being female
• Thin and/or small frame
• Advanced age
• A family history of osteoporosis
• Postmenopausal
• Abnormal absence of menstrual periods (amenorrhea)
• Anorexia nervosa
• Diet low in calcium certain medications (corticosteroids, anticonvulsants)
• Low testosterone levels in men
• An inactive lifestyle
• Cigarette smoking
• Excessive use of alcohol
• Caucasian or Asian

abnormally low levels of sex hormones

Weight bearing exercises

• Primarily associated with increased osteoclast activity
• Rapid bone loss
• Decreased estrogen levels in females and testosterone levels in males
• Estrogen dampens the bone resorbing effects of PTH when there is a decreased blood Ca
• Lower estrogen:PTH ratio during menopause
• Vertebral bone crush, high risk of wrist and spine fractures
• Females:males 6:1

• Senile osteoporosis
• Cortical bone loss
• Slow and steady with age
• Start at ~40 years of age
• Due to osteoblast underactivity
• Females:males= 2:1

• Acquisition of maximum bone mass in premenopausal years
• Adequate dietary Ca and vitamin D
• Screening for osteopenia and perimenopausal period
• Decrease of BMD more than 1SD but less than 2.5 below the young adult mean
• Control of bone mineral loss during postmenopause

Hormone replacement therapy

• Elderly and women with osteoporosis 
• Thought to absorb Ca less efficiently because of a deficiency in the activated form of vitamin D
• Decreased bone resorption (enhancement of Ca absorption in the gut)
• Aids in the mineralization of the bone matrix

• Decreased calcium, Increased phosphorus, high protein diet, vitamin D deficiency, low physical activity, excess alcohol and caffeine and smoking
• Exercise: stimulates osteogenesis, believed to be helpful in retarding bone loss

receptor activated nk-kappa-ligand, stimulates inflammation and causes the breakdown of bone matrix