Chapter 10-12: Water, Electrolytes, Minerals, Trace Elements Flashcards
What are some consequences of dehydration?
- headache
- fatigue
- dry mouth & eyes
- dark-coloured urine
More serious…. - nausea
- confusion
- disorientation
- death (10-20% loss)
What are some examples of electrolytes?
1) Sodium
2) Potassium
3) Chloride
What is hyponatremia?
- water intoxication
- excessive intake of water during prolonged exercise (low blood sodium)
- water moves out of blood into tissue –> swelling & damage to organs
- early symptoms are similar to dehydration
How are Canadians doing with respect to their intake of sodium and potassium from food?
1) too much sodium
2) not enough potassium
ns potassium intake may or may not be adequate
What effect does processing have on sodium and potassium contents of food?
1) Less processed: same amount of potassium, less sodium
2) More processed: potassium amounts do not change much, sodium levels skyrocket
What is a cation?
an ion with fewer electrons than protons (i.e. positively-charged)
- potassium = the major cation in the cell
- sodium = major cation outside of the cell
What maintains the balance between potassium and sodium in and around the cell?
Na-K-ATPase pump (sodium-potassium-ATPase pump)
What is the difference between interstitial & intracellular fluid?
- interstitial fluid = extracellular fluid (outside of the cell)
- intracellular fluid = cystol (inside the cell)
What is one of the main functions of electrolytes?
Regulation of blood pressure
- release of aldosterone from adrenal glands increases sodium reabsorption by the kidneys –> water follows the sodium, helping to maintain blood volume & blood pressure
What is hypertension?
Chronically (persistently) high blood pressure
- due to salt sensitivity –> slow sodium secretion + sodium causes constriction of blood vessels –> high blood pressure persists
What is the big contention surrounding sodium intake?
years of warnings to cut sodium consumption to reduce heart attack & stroke, but there is little evidence supporting that such reductions would actually be beneficial
- emerging evidence that sodium levels that are too low can be harmful
Is there a U-shaped curve for sodium?
Yes RDA = 1500mg UL = 2300mg AI = 500mg *however, there is no evidence for an additional benefit to lowering from 2300mg to 1500mg
What is the health claim on labels associated with potassium & sodium?
“A healthy diet high in potassium and low in sodium reduces the risk of high blood pressure, which is a risk factor for stroke and heart disease”
Diets high in potassium can counterbalance the effects of ____.
sodium
Which has the most potassium: banana, baked potato, or orange juice?
Baked potato has the most, followed by banana, then orange juice.
What are the complications of pregnancy related to electrolytes?
1) Gestational hypertension
2) Pre-eclampsia (high blood pressure, fluid retention, rapid weight gain)
3) Eclampsia (seizures, death)
What is the DASH eating plan?
A diet plan for reducing blood pressure
- similar to Canada’s Food Guide
- high in foods that contain potassium, calcium & magnesium
What is the health impact of combining the DASH plan with reductions in sodium?
DASH plan + low sodium –> reduced blood pressure more than low sodium or DASH on its own
- decrease in sodium lowered blood pressure more in control diet than in DASH diet group (maybe b/c blood pressure was already lower in DASH diet?)
What are minerals?
Inorganic elements needed by the body in small amounts
What are the 7 major minerals?
1) Sodium (Na)
2) Magnesium (Mg)
3) Potassium (K)
4) Calcium (Ca)
5) Phosphorous (P)
6) Sulfur (S)
7) Chlorine (Cl)
What are the trace minerals?
1) Lithium (Li)
2) Rubidium (Rb)
3) Vanadium (V)
4) Chromium (Cr)
5) Manganese (Mn)
6) Iron (Fe)
7) Molybdenum (Mo)
8) Nickel (Ni)
9) Copper (Cu)
10) Zinc (Zn)
11) Cadmium (Cd)
12) Boron (B)
13) Aluminum (Al)
14) Silicon (Si)
15) Germanium (Ge)
16) Arsenic (As)
17) Selenium (Se)
18) Bromine (Br)
19) Tin (Sn)
20) Lead (Pb)
21) Iodine (I)
22) Fluorine (F)
How are minerals consumed in the Canadian diet?
1) Natural sources
2) Fortified foods (i.e. iron, calcium, iodine)
3) Natural health products (ex. supplements; calcium for older women)
What are phytates, oxalates, and tannins?
- compounds that decrease absorption of minerals by binding them
1) Phytate –> grains (calcium, zinc, iron, magnesium)
2) Oxalate –> spinach & other veggies (calcium, iron)
3) Tannins –> tea & coffee (calcium, iron)
How does the absorption (bioavailability) of iron & calcium compare with that of sodium?
- sodium has 100% absorption
- iron & calcium have low absorption/bioavailability
How are Canadians doing with respect to their intake of calcium from food & supplements?
- high prevalence of inadequate intake across the board
How are Canadians doing with respect to intake of magnesium & phosphorous in food?
- high prevalence of inadequate intake of magnesium
- low prevalence of inadequate intake of phosphorous
What are minerals as cofactors?
- many minerals serve as cofactors (make the enzyme active)
- ex. selenium is a cofactor for an antioxidant enzyme system
- mineral cofactor combines w. incomplete enzyme to form active enzyme
What is the main purpose of calcium?
Bone structure & health
- calcium levels in the blood must be maintained in a very narrow range
What happens when calcium blood levels are low? What may this lead to over time?
calcium is taken from bone
- may lead to osteoporosis over a lifetime
How is calcium absorbed?
1) Vitamin D promotes synthesis of calcium transport proteins
2) Calcium is carried across the enterocyte
3) Calcium pump (that req’s energy) moves into the blood
How does calcium absorption differ across age groups?
Infants –> 60% absorption
Adults –> 25-30%
Adults w. vitamin D deficiency –> as low as 10%
During pregnancy –> absorption increases (so RDA for calcium in pregnancy is unchanged)
RDA of calcium takes into account the _____.
low absorption rate
- body needs 300mg/day to meet needs, so RDA = 1,000mg
How is bioavailability of calcium affected?
- decreased by tannins, fibre, phytates, oxalates
Vegetables low in oxalate are good sources of ____.
CALCIUM
- ex. kale, collard greens, chinese cabbage
How are Canadians doing with respect to their intake of calcium from food & supplements?
- high prevalence of inadequate intake across the board
How are Canadians doing with respect to intake of magnesium & phosphorous in food?
- high prevalence of inadequate intake of magnesium
- low prevalence of inadequate intake of phosphorous
What is the main purpose of calcium?
Bone structure & health
- calcium levels in the blood must be maintained in a very narrow range
What happens when calcium blood levels are low? What may this lead to over time?
calcium is taken from bone
- may lead to osteoporosis over a lifetime
How is calcium absorbed?
1) Vitamin D promotes synthesis of calcium transport proteins
2) Calcium is carried across the enterocyte
3) Calcium pump (that req’s energy) moves into the blood