Lecture 7 Flashcards
how long can you survive without water?
a few days
what % of an adults body weight is water?
60%
water characteristics
- found in blood and cells all throughout body
- participates in many chemical reactions
- delivers nutrients and removes waste from cells
functions of water
- universal solvent
- body’s cleansing agent
- incompressibility
- lubricates
- role in thermoregulation
water as a universal solvent?
- dissolves amino acids, glucose, minerals etc for transport
- fatty substances get packaged with water-soluble proteins for transport in blood and lymph
water as the body’s cleansing agent
- nitrogen waste dissolve in blood and must be removed
- kidneys filter these wastes and mix them with water to be excreted as urine
waters incompressibility
- enables it to act as a lubricant and cushion for joints
- cushions sensitive tissues (spinal cord and fetus)
- fills eye keeping optimal pressure
water lubricate function
mucus moistens the digestive tract, respiratory tract, and all tissues
waters role in thermoregulation
- sweat cools the body (evaporation)
- blood routed through capillaries in skin gets rid of excess heat
- cooled blood flows back to body’s core
water balance
water intake needs to equal water loss
what happens if water intake doesn’t equal water loss?
dehydration or water intoxication/over-hydration can occur
dehydration progression of symptoms
- thirst
- weakness
- exhaustion and delirium
- death
loss of <5% bodyweight due to dehydration symptoms
- headache
- fatigue
- confusion
- forgetfulness
- elevated heart rate
what may chronic low fluid increase likelihood of?
- bladder and colon cancer
- heart attack
- gallstones
- kidney stones
- urinary tract infections
water intoxication
very dangerous dilution of body fluids due to excessive water ingestion (gallons or more in few hours)
symptoms of water intoxication
- headache
- muscular weakness
- lack of concentration
- poor memory
- loss of appetite
- convulsions and death
body and sodium
- high-salt meals lead to water retention
- water is lost over a 1-2 day period as sodium is excreted
bodys water content
varies by kilograms at a time
hypothalamus
- major role in monitoring blood concentration
- high blood concentration (salt) or low blood pressure signals thirst
ignoring thirst
leads to dehydration
- drink whenever thirsty to replace lost fluids
older adults and thirst
thirst is blunted in older adults so they should drink regularly throughout the day
prolonged vomiting or diarrhea
- could result in fluid and electrolyte imbalance
- life-threatening disruption of heartbeat
how much water should females drink per day?
2.7 L/day
how much water should males drink per day?
3.7 L/day
what does total water intake include?
- caffeinated and non-caffeinated beverages
- food
water content of foods
- meat and cheese (50%)
- veggies and fruit (80-95%
hard water
water with high calcium and magnesium
soft water
water with high sodium
- may aggravate hypertension and heart disease
what is left behind upon death?
minerals (about 2.3kg)
minerals
- chemical elements
- inorganic
- not energy yielding
- micronutrients
minerals and cooking
not destroyed by cooking or storing
- may leach into cooking water
bioavailability of minerals
binders such as phytates in legumes, bind with minerals decreasing their absorption
major minerals characteristics
- essential nutrients
- amounts exceed 5 grams
trace minerals characteristics
- essential nutrients
- amounts less than 5 grams
the major minerals
- calcium
- phosphorus
- potassium
- sulphur
- sodium
- chloride
- magnesium
calcium
- most abundant mineral in the body
- 99% stored in bones and teeth
what is the most abundant mineral in the body?
calcium
calcium 2 major roles in bones
- integral part of bone structure
- bone serves as a calcium reserve
what minerals are essential to bone formation?
calcium and phosphorus
bone fomation
- calcium phosphate salts crystallize on collagen, forming hydroxyapatite crystals that add rigidity to bone
- fluoride may displace hydroxy making fluorapatite
fluorapatite
mineral that resits bone-dismantling
formation of teeth
similar to bone
- fluoride hardens and stabilizes the crystals of teeth and makes enamel resistant to decay
calcium concentration in blood
- calcium conc is constant in blood
- blood calcium is regulated by hormones (not daily intake)
what happens if calcium intake is inadequate?
normal blood calcium is maintained at expense of the bones
what happens when calcium need increases?
- calcium absorption from intestine increases
- loss of calcium via the kidneys is reduced
- percent absorbed increases as dietary intake decreases (with help of vitamin D)
bone loss
- by late 20s peak bone mass is reached
- after 40 bones begin to reduce density
how can bone loss be slowed
- a diet rich in calcium
- sufficient physical activity
calcium-poor diet during growing years
may prevent a person from achieving peak bone mass
insufficient bone calcium
increases risk of osteoporosis
(bones become brittle and fragile)
what % of calcium is in the body fluids?
1%
1% of calcium in the body fluids role
- muscle concentration and relaxation
- nerve functioning
- blood clotting
good calcium sources
- milk and milk products
- fortified soy beverages and other fortified milk alternatives
- fish with bones
- calcium set tofu
- broccoli, some leafy greens and legumes
- fortified juices
calcium deficiency adults
bone loss
calcium deficiency children
stunted growth and weak bones
calcium deficiency
- consumption of milk has declines
- consumption of beverages such as soft drinks increased
calcium toxicity symptoms
- constipation
- kidney stones
- interferes with absorption of other minerals
milk and milk replacements
people who don’t drink milk for many reasons must obtain calcium from other sources
children who don’t drink milk
- often have lower calcium intakes
- often have poorer bone health than those who drink milk regularly
veggies good sources of calcium
- rutabaga
- broccoli
- beet greens
- collards
- kale
veggies poor sources of calcium
- spinach, swiss chard, rhubarb
- binders in some veggies inhibit calcium absorption
spinich
- still good to eat
- iron, beta-carotene and phytochemicals rich
- poor calcium source
dark greens of all kinds
- great source of riboflavin
- indispensable for vegans or anyone else who doesn’t drink milk
osteomalacia
vitamin D deficiency disease leads to impaired mineralization of bone
characteristics of osteomalacia
- overabundance of unmineralized bone protein
- ratio of bone mineral to matrix is low
symptoms of osteromalacia
- bending of spine
- bowing of legs
osteoporosis
reduction in bone mass of older persons in which the bone becomes porous and fragile
- bone mineral to matrix ratio is normal
are osteoporotic fractures more common in males or females?
women (1 in 3)
hip fractures due to osteoporosis
- most serious - rarely clean break (into fragments)
- requires major surgery
- many elderly people never walk or live independently again
- 1/5 die within a year
osteoporosis development
develops silently (silent thief)
- slowly decreasing bone density until many years later, hip gives away
high correlation risk factors for osteoporosis
- age (advancing)
- sex
- heavy drinking
- chronic steroid use
- rheumatoid arthritis
- underweight/weight loss
- removal of ovaries or testes
- genetics (fam history)
- race
what race is at more at risk for osteoporosis?
white people
moderate correlation risk factors of osteoporosis
- chronic thyroid hormone use
- smoking
- type I diabetes
- insufficient dietary calcium and vitamin D
- inadequate vitamin K
- physical inactivity
- excessive antacid use
black people and osteoporosis
more protective against osteoporosis
- black women have denser bones and lose density more slowly than white women
sex and osteoporosis
women = 2/3 cases of osteoporosis
- men have greater bone density
hormones and osteoporosis
- women experience greater bone loss during menopause
- bone loss tapers off after 6-8 years following menopause
- men produce only little estrogen, yet they resist osteoporosis better than women
testosterone and osteoporosis
men experience more fractures with reduced testosterone
ex. after removal of diseased testes or decreased function with aging
physical activity and osteoporosis
without PA, bone lose strength
muscle use
promote bone strength
- active people have denser bones
flexibility and muscle strength
gained through physical activity also improves balance and help prevent falls from occuring
what to do to keep bones healthy and to prevent falls?
include weight bearing activities every day
- calisthenics, dancing, jogging, vigorous walking, weight training
body weight and osteoporosis
- being underweight increases risk
- heavier body weights and higher fatness stress the bones and promote their maintenance (but obesity may have negative effect)
tobacco smoke, alcohol and osteoporosis
- smokers have less dense bones
- people with heavy alcohol use experience more frequent fractures
high protein diet and osteoporosis
- excess protein causes body to excrete calcium is urine
- sufficient dietary protein is essential to bone health
sodium and osteoporosis
- high sodium intake associated with urinary calcium excretion
- lowering sodium intakes seems to lessen calcium loss
diet to lower sodium and increase potassium intake
- rich in unprocessed foods (fruits and veggies)
- restricted in highly processed, convenience, or fast foods
caffeine and osteoporosis
link between heavy consumption of caffeine and osteoporosis
soft drinks and osteoporosis
high conc of fructose from pop or phosphoric acid may cause calcium loss
- displace milk from diet
vitamin K and osteoporosis
plays important roles in production of at least one bone protein (osteocalcin) that participates in bone maintenance
- people with hip fractures often have low vitamin K
magnesium and bones
helps maintain bone density
vitamin A and osteoporosis
- needed in bone-remodeling process
- too much may be associated with osteoporosis
what is the second most abundant mineral in the body?
phosphorus
where is the majority of phosphorus found?
bones and teeth
phosphorus function
- helps maintain acid-base balance (buffers)
- part of DNA and RNA
- part of molecules of phospholipids
- metabolism of energy yielding nutrients
- assist many enzymes and vitamins in extracting energy
phosphorus needs
easily met by almost any diet
phosphorus toxicity
calcification of soft tissues
phosphorus sources
- animal proteins are best sources
- cola drinks
where is magnesium stored
- half of body’s magnesium in bones
- remainder in muscles, heart, liver and other soft tissues
- only 1% in body fluids
how do you maintain concentration of magnesium in the blood?
- magnesium can be taken from bones
- kidneys can act to conserve magnesium
magnesium functions
- assists in functioning of more than 300 enzymes
- release and use of energy from energy-yielding nutrients
- works with calcium for functioning of muscles
calcium and magnesium relationship
- calcium promotes contraction
- magnesium helps muscles relax afterwards
- magnesium is involved in bone mineralization and promotes resistance to tooth decay by holding calcium in tooth enamel
sources of magnesium
- nuts and legumes
- whole grains
- dark green veggies
- seafood
- chocolate
- easily washed and peeling away from foods during processing
best source of magnesium
unprocessed foods
- most canadians reach EAR but not RDA
what may a magnesium deficiency occur as a result of?
- inadequate intake
- vomiting
- diarrhea
- alcoholism
- protein energy undernutrition
magnesium deficiency symptoms
- muscle weakness
- could relate to CVD, heart attack, high blood pressure
magnesium toxicity
- rare but can be fatal
- only occurs with high intakes from non-food sources such as supplements or magnesium salts
magnesium laxatives and antacids
can cause diarrhea and acid-base imbalance
sodium function
- fluid and electrolyte balance
- acid-base balance
- muscle contraction and nerve transmission
- 30-40% stored in bone crystals - easily accessible to maintain blood levels
sodium deficiency
unlikely - generally eat more salt than needed
strict low-sodium diet
used for hypertension, kidney diseases or congestive heart failure
causes of sodium deficiency
- vomiting
- diarrhea
- extremely heavy sweating
endurance athletes and sodium
endurance athletes can lose so much salt and drink so much water they become hyponatremic
symptoms of hyponatremic
- headache
- confusion
- stupor
- seizures
- coma
maintenance of sodium
- body absorbed sodium freely
- kidneys filter excess sodium out of blood into urine
- kidneys conserve sodium
- small sodium losses occur in sweat
- amount of sodium excreted in a day = amount ingested that day
salt and “water weight”
- as blood sodium rises, a person get thirsty to drink until sodium-to-water ratio to restored
- kidneys excrete extra water to remove excess sodium
- not fat gain, excess water which healthy body will excrete
how do you keep body salt and water weight under control?
controlling sodium intake and increasing water intake
adequate intake of sodium
1500 mg/day (14 and up)
CDRR for sodium
2300 mg/day (14 and up)
hypertension
salt (NaCl) seems to have a greater effect on blood pressure than either sodium or chloride alone
excess sodium intake and sex
males consume more excess sodium than females
sodium and blood pressure
- more salt = higher blood pressure
- increasing blood pressure = increasing risk of death from CVD
sodium and salt sensitivity
in salt-sensitive people, the more salt they eat the higher their blood pressure
salt-sensitive people
- people with diabetes, hypertension or kidney disease
- african descent
- fam history of high BP
- over age 50
reducing salt for high BP
only really need to if salt-sensitive
- try reasonable weight loss, adding fruits and veggies, fatty fish, milk/milk products
what diet approach may hep salt-sensitive and non-salt-sensitive people?
DASH diet
DASH meaning
Dietary Approaches to Stop Hypertension
DASH diet
- increase veggies and fruits
- nuts, fish, whole grains, low-fat dairy products
- occasional red meat, butter and other high-fat foods and sweet s
- salt and sodium greatly reduced
sodium and potassium relationship
- low potassium intake found to raise BP
- high potassium intake appears to both help prevent and correct hypertension
PA and BP
PA lowers BP
stroke and sodium
older people can die of stroke
- reducing sodium may lower blood pressure enough to reduce stroke risks
excessive salt
- stresses a weakened heart (congestive heart failure)
- aggravates kidney problems
- may be potential contributor to stomach cancer
contributors to sodium in the diet
- unprocessed foods (15%)
- salt (10%)
- processed foods (75%)
sources of sodium (processed foods)
- canned soup and dried soup mixes
- cured meats, deli meats, hot dogs
- cheese
- foods in brine (pickles, coleslaw)
- TV dinners ans fast food
- canned pasta sauce
how much sodium in 1 tsp of salt
2300 mg sodium
other sources of sodium
- salt
- soy sauce
- onion salt
- garlic salt
- worcestershire sauce
chloride
major negative ion in the body
chloride function
- acid-base balance
- electrolyte balance
- component of hydrochloric acid
sources of chloride
salt: both added and naturally occuring
chloride deficiency
no known diet lacks chloride
potassium
principle positively charged ion inside the bodys cells
potassium functions
- maintenance of fluid balance
- maintenance of electrolyte balance
- maintenance of heartbeat
potassium deficiency and heart failure
may cause sudden death that occur with:
1. fasting or severe diarrhea
2. children with kwashiorkor
3. people with eating disorders
potassium loss
- could be due to dehydration or diuretics
- makes hypertension worse
sources of potassium
- richest sources of potassium are fresh, whole foods
- oranges (juice), bananas, potatoes, tomatoes, avocados, strawbs, spinach, cantaloupes
food processing and potassium
food processing reduces the potassium in foods
potassium toxicity
- potassium from food is safe
- potassium injected into vein can stop the heart
- salt substitutes often contain high amounts
- usually not life-threatening as long as the excess potassium is taken orally (vomiting reflex)
over the counter potassium chloride pills
should not be used except on a physicians/nurses advice
function of sulphur/sulphate
required for synthesis of many important sulphur-containing compounds
- sulphur containing amino acids
sulphur-containing amino acids
- help strands of protein assume their functional shape
- skin, hair and nails proteins with high sulphur
sources of sulphur/sulphate
protein containing foods
sulphur/sulphate toxicity symptom
diarrhea
