12) Adulthood and the Elderly (Part II) Flashcards
When does the number of functional taste buds decrease?
60 years of age
What are the consequences of a decrease in the number of functional taste buds?
- Decreases the capacity to taste and smell
- Reduces appetite
- Decreases palatability
- Decreases food intake
- Prescribed diets are low in taste
What are the components of saliva?
- Water
- Electrolytes
- Mucus
- Glycoprotein enzymes
- Anti-bacterial compounds (IgA, lysozyme)
What are the three primary functions of saliva?
1) Initiates the process of digestion of dietary starches and fats
2) Play a role in protection against dental caries
3) Lubricates food, allowing for the initiation of swallowing
What is xerostomia?
Dry-mouth
Xerostomia is present in 20% of the elderly. What are possible causes? (2)
- Drug intake (anti-hypertensives, anti-depressants, bronchodilators)
- Disease (e.g. autoimmune disease)
What are the effects of a decrease in salivary secretion?
Increases the risk of infections and ulcers
What is the effect of a decreased ability to swallow (dysphagia) due to a decreased salivary secretion?
May result in a decreased food intake
What is a likely consequence of a decrease in esophageal function?
Dysphagia
What are causes of dysphagia? (3)
- CNS changes
- Diabetic neuropathy
- Parkinson’s disease
An individual is prone to dysphagia if there is impaired __________ function.
esophageal
Choking increases the risk of which disease? Why?
- Pneumonia
- Food may be aspirated into the lungs
- Choking is one of the leading causes of death among the elderly population
What are the primary functions of gastric acid?
- Acts as a chemical barrier against pathogenic colonization
- Facilitates food digestion
What does the stomach lining contain to protect from gastric acid? What occurs if these mechanisms fail?
- A layer of thick mucus containing sodium bicarbonate
- Heartburn or peptic ulcers may develop
Which gastric functions are impaired due to aging?
- Decrease in gastric acid production
- Decrease in parietal cell mass
- Decrease in the maintenance of commensal flora bacteria
What are the effects of a decrease in pepsin due to aging?
- Decreases proteolysis
- Results in a decreased vitamin B12 exposure to intrinsic factor
- Decreased absorption of vitamin B12
What are the effects of hypochlorhydria due to aging?
- Increase in pH in the proximal small intestine
- Causes bacterial overgrowth of the small GI (streptococci, lactobacilli)
What is the effect of bacterial overgrowth of the small GI?
These bacteria compete for B-vitamins, which decreases optimal nutrient availability
Dyspepsia increases the risk of ______.
ulcers
What are the functions of the liver?
- Glycogen storage
- Decomposition of RBCs
- Plasma protein synthesis
- Hormone production
- Detoxification
Why is the elderly highly susceptible to drug-related toxicity?
The liver no longer has the capacity to metabolize compounds properly due to a reduced production of drug-metabolizing enzymes
What are the effects of a decrease in bile production with age?
- Increases food intolerance (fatty foods)
- Increases GI distress, causing gas, nausea, vomiting and diarrhea
What are the effects of a decrease in the functioning sections of the pancreas with age?
A decrease in digestive enzyme production and nutrient absorption in the small intestine may occur with age, particularly if there is an underlying chronic disease
What are causes of an increased risk of constipation in the elderly?
- Low-fiber intake due to food intolerance
- Difficulty consuming fibrous foods
What are the effects of diverticulosis?
- Discomfort
- Diarrhea
- Constipation
- May lead to diverticulosis (bleeding and bowel obstruction)
Which nutrient deficiencies are related to lactose intolerance?
- Vitamin A
- Vitamin D
- Vitamin B2
- Protein
What are functions of the kidney?
- Regulation of electrolytes
- Maintaining acid/base balance
- Regulating blood pressure
The renal mass decreases by 30% by __ years of age.
90
What are the effects of a decrease in renal mass?
1) Decreases renal function
2) Decreases the capacity to excrete waste products from diets with a high intake of protein or electrolytes
What are the effects of glomerulonephritis?
Difficulties in the excretion of drugs and vitamins when taken in excess
Which nutrient deficiencies are related to a decrease in renal function? Why?
- Vitamin D because the kidneys are responsible for its bioactivation
- Water, glucose and amino acids, which are excreted instead of absorbed
How does the decline in renal function affect thirst mechanisms?
Increases the risk of dehydration, which is further exacerbated by the heavy use of diuretics and laxatives
What is the effect of the decrease in function of the liver AND kidney?
- Accumulation of drug metabolites
- May trigger a type III hypersensitivity response
What occurs during a type III hypersensitivity response?
- IgG and complement components attempt to bind to metabolites, forming immune complexes, which become subject of complement deposition, opsonization and phagocytosis
- Glomerulonephritis may occur as a response
About __% of individuals that are greater than 75 years of age meet the criteria for chronic kidney disease.
50
What are the five ways anti-vitamin drugs may block the actions of vitamins? (5)
1) Inhibiting their absorption
2) Binding to them (making them unavailable)
3) Enhancing their catabolism
4) Enhancing their excretion
5) Causing an inhibition of their activation in the body to an active form
What is polypharmacy a strong predictor for?
Malnutrition
Why is polypharmacy a strong predictor for malnutrition in the elderly?
- With increasing age, the body’s ability to metabolize drugs decreases
- The elderly is normally prescribed multiple medications
What are the four mechanisms by which drugs undergo movement in the body?
- Absorption
- Distribution
- Metabolism
- Excretion
What are possible effects of low serum albumin concentration on drugs?
May increase the availability of drugs and potentiate their effects
Where does drug metabolism normally occur? What is it facilitated by? What normally occurs?
- Liver
- Cytochrome P-450
- Conversion of fat-soluble compounds to water-soluble compounds
What are the effects of grapefruit on drug metabolism? What is the mechanism by which this occurs?
- Inhibit intestinal metabolism (by inhibiting cytochrome P-450) of numerous drugs
- Enhances their effects and risks of toxicity
Why have hospitals and healthcare centers removed grapefruit from their menu?
- Grapefruit enhances the risk of toxicity of certain drugs
- The effects may persist for 72 hours
What are the effects of monoamine oxidase inhibitors on nutrient metabolism?
- Prevent the breakdown of pressor agents in food (substances that increase BP)
- May cause a hypertensive crisis
What are the effects of vitamin K on Warfarin?
Vitamin K allows for the production of more clotting factors, making Warfarin less effective
What are the effects of Methotrexate and pyrimethamine on nutrient metabolism?
Folic acid antagonists
How may folic acid deficiency be prevented in individuals consuming folic acid antagonists?
- Consumption of greater folic acid
- Consumption of folinic acid (reduced form of folic acid), which does not require conversion to the active form
What drug may increase the risk of GI bleeding if ingested with alcohol?
NSAIDs
Define a drug-nutrient interaction.
The result of action between a drug and a nutrient that would not happen with the nutrient or the drug alone
Define a food-drug interaction.
Broad term that includes drug-nutrient interactions and the effect of a medication on
nutritional status
How do cholesterol-lowering drugs affect nutrient metabolism?
- Act as bile acid sequestrants, preventing reabsorption of bile salts
- Decreases fat-soluble vitamin absorption
How do antibiotics affect nutrient metabolism?
- Damage to the GI tract
- Destroying intestinal mucosa, villi and microvilli, as well as brush-border enzymes
- Reduces nutrient absorption
How do anti-inflammatory drugs affect nutrient metabolism? (3)
1) Inhibit lactase
2) Directly damage the gut
3) Decrease fat and micronutrient absorption
How do laxatives affect nutrient metabolism? What do they contain?
May contain emollients, which dissolve fats and fat-soluble vitamins, which are subsequently excreted in feces
Which nutrients do laxatives influence? Why?
- Fats and fat-soluble vitamins (contain emollients)
- Calcium and potassium (decreased transit time)
A high-fiber diet may decrease the absorption of which medication?
Tricyclic anti-depressants
Which medications alter the ability to absorb minerals, particularly iron and calcium?
- Chemotherapeutic agents
- NSAIDs
- Antibiotics
How do anti-ulcer drugs affect nutrient metabolism?
- Decreases HCl production
- Decreases intrinsic factor secretion, and binding/absorption of vitamin B12
How do anti-ulcer drugs affect the pH of the GI tract?
Increase in pH
What are the effects of an increase in pH on nutrient metabolism? Which nutrients are affected?
Impairs the absorption of calcium, iron, zinc, folic acid and B-carotene
Which nutrients do Ciproflaxacin and tetracycline complex with?
- Calcium
- Iron
- Magnesium
- Zinc
What is the mechanism of action of loop diuretics?
Inhibit the sodium-potassium co-transporter in the thick ascending loop of Henle
Which nutrient do loop diuretics affect?
Increase the renal excretion of thiamine
Which nutrients do thiazide diuretics affect?
- Increase the excretion of potassium and magnesium
- Reduce the excretion of calcium
What is a possible effect of a high dosage of a thiazide diuretic?
Hypercalcemia
Which nutrients do potassium-sparing diuretics affect?
Increase the excretion of sodium, chloride and calcium
Which nutrient does aspirin affect? How?
- Increases folate excretion
- By binding to folate-binding sites on albumin
Which drugs are more potent if there are low albumin levels? (3)
- Aspirin
- Phenytoin
- Warfarin
What are the effects of a greater proportion of adipose tissue on drug metabolism?
Causes fat-soluble drugs to accumulate, which increases the risk of toxicity
Which nutrients do corticosteroids affect?
- Decrease sodium and water excretion
- Increase potassium and calcium excretion
Which supplements are recommended in an individual utilizing corticosteroids?
- Potassium
- Calcium
- Vitamin D
What is particular about Alendronate, an anti-osteoporosis drug?
Must be ingested while sitting upright for 30 minutes to avoid esophagitis
What is acute diarrhea?
An episode lasting less than 2 weeks
What is chronic diarrhea?
Diarrhea lasting from 3 to 6 weeks
What may be due to the increase in likelihood of developing diarrhea with age?
Changes in immune and non-immune defenses associated with age
What is the most common cause of diarrhea in the elderly? What is it related to?
- Drug therapy
- Dose-related
What is the most common iatrogenic cause of diarrhea in the elderly? What are the characteristics?
- Antibiotics
- Often mild and self-limiting
How do antibiotics cause diarrhea?
- Results in a temporary alteration of the colonic bacteria and may damage the small intestinal mucosa
- Decreases colonic fermentation of carbohydrates, which act as osmotic agents
What are examples of osmotic agents that may cause diarrhea?
- Anti-ulcer medication (Cimetidine)
- Laxatives
- Antacids
How do antineoplastic drugs cause diarrhea?
Damaging immature epithelial cells, compromising their absorptive funciton
What are contributing factors to drug therapy-related diarrhea? (4)
- Polypharmacy
- Self-medication
- Non-compliance
- Inappropriate drug prescribing
Define bone remodeling.
The replacement of old bone with newly synthesized bone tissue
What is the primary function of osteoblasts?
Synthesize the bone matrix
What are the primary functions of osteoclasts?
- Dissolve bone minerals with acids
- Digest the bone matrix with the recruitment of phagocytes to remove the protein
Define osteoporosis.
- Reduced bone of normal composition
- Bone density is 2.5 SD below the level of healthy young individuals
What postpones osteoporosis?
A high peak bone mass early in life
How does bone formation compare to resorption before peak bone mass is reached?
Bone formation continues at a pace that is faster than resorption
What is the yearly resorbed bone loss that occurs from age 30 to menopause?
1.2% per year
What is the yearly resorbed bone loss that occurs for 6 to 8 years during menopause?
3 to 5% per year
What is the main determinant of peak bone mass?
Calcium intake
When does the maximal rate of accretion of bone mass occur?
During the pubertal growth spurt
When do men and women experience the same rapid bone loss?
- In their 50s, men do not experience rapid bone loss
- By 65 or 70, men and women experience the same bone loss
What are the three factors that place men at a decreased risk for developing osteoporosis? (3)
1) Their larger skeleton
2) Bone loss starting later and slower in men
3) The lack of rapid hormonal changes in men
Which hormones, affected by aging, increase the risks of developing osteoporosis?
- Decrease in GH
- Decrease in hepatic IGF-1
- Decrease in sex hormones
How may anorexia predispose an individual to osteoporosis?
- Decrease in estrogen due to low-body weight
- Calcium deficiency
- Malnutrition
How do glucocorticoids predispose an individual to osteoporosis?
- Suppress bone formation
- Impair osteoblastogenesis
- Inhibit the synthesis of IGF-1
Which cells are associated with type I osteoporosis? How do they vary?
Increase in osteoclast activity
What is post-menopausal osteoporosis?
Type I osteoporosis
What is senile osteoporosis?
Type II osteoporosis
Which type of bone is lost in type I osteoporosis?
Trabecular bone
What are the two mechanisms by which estrogen prevent osteoporosis?
1) Stimulates apoptosis of osteoclast precursor cells
2) Suppress the production of bone-resorbing cytokines
What is the age of onset of type I osteoporosis?
50 to 70 years of age
The ratio of which hormones is associated with a greater risk of developing type I osteoporosis?
- Menopause causes a lower estrogen to PTH ratio
- PTH mobilizes calcium from bone, increasing bone resorption
Which type of bone is lost in type II osteoporosis?
Cortical bone loss
What is the age of onset of type II osteoporosis?
- 40 years of age
- Occurs slowly and steadily
Which cells are associated with type II osteoporosis? How do they vary?
Underactivity of osteoblast
If the cause of type II osteoporosis is age-related, what is it called?
Senile osteoporosis
If the cause of type II osteoporosis is unknown, what is it called?
Idiopathic osteoporosis
What is the predominant feature of age-related bone loss?
The accumulation of bone marrow fat at the expense of osteoblastogenesis
How do adipocytes affect osteoblasts?
Adipocytes inhibit osteoblast activity
Which hormone plays a greater role in age-related bone loss in men: estrogen or testosterone?
Estrogen
______ and ______ deficiencies contribute to secondary hyperparathyroidism.
Calcium
vitamin D
How does hyperparathyroidism affect osteoclastic activity?
Increases osteoclastic activity and cortical bone loss
The screening for what should occur during the peri-menopausal period?
Osteopenia
Define osteopenia.
Bone mineral density above one SD and below 2.5 SD of the young adult mean
Which nutrient may aid in the control of bone mineral loss during post-menopause?
Calcium
What are causes of estrogen deficiency?
- Decrease in ovarian function
- Anorexia nervosa
- Removal of ovaries
Which treatments for osteoporosis have fallen out of recommendation in recent years? Why?
- Hormone replacement therapy (HRT) and selective estrogen receptor modulators (SERMs)
- Increased risk of breast cancer and CVD
What is the first line of treatment for osteoporosis?
Bisphosphonates
What are the mechanisms of action of bisphosphonates? (3)
1) Osteoclast apoptosis
2) Osteoblast differentiation
3) Inhibition of bone marrow adipogenesis
Why are the elderly and women with osteoporosis thought to absorb calcium less efficiently?
Due to a deficiency in the active form of vitamin D
Which derivative of vitamin D has demonstrated beneficial effects on bone mass in women with osteoporosis? What are common side effects?
- Calcitriol
- Hypercalcemia and hypercalciuria
Which type of diet may increase bone loss?
- Low calcium
- Low vitamin D
- High phosphorus
- High protein
Which lifestyle factors may increase bone loss?
- Low physical activity
- Excess alcohol
- Caffeine
- Smoking
