Major Minerals Flashcards
Sodium
= most abundant cation in ECF
easily absorbed in GI tract
AI = 1500 mg/day or 3600 mg/day of salt
UL = 2300 mg/day
Sodium functions
resting membrane potential
blood volume
nerve impulse transmission
muscle contraction
Sodium excess
HTN: 50% people with HTN = sodium sensitive
edema
exagerrated in cases of potassium and magnesium deficiency
Sodium deficiency
{hyponatremia}
HA thirst confusion coma death caused by excessive sweating, vomiting, diarrhea, reduced intake, diuretic meds
Chloride
most abundant anion in ECF maintains fluid balance necessary for gastric HCl production AI = 2300 mg/day UL = 3600 mg/day
Chloride excess
vomiting
deficiency = rare
Potassium
main cation in ICF
AI = 4700 mg/day
Potassium functions
resting membrane potential fluid balance maintenance cell integrity nerve impulses muscle contraction
Potassium toxicity
{ hyperkalemia }
muscle weakness
peripheral neuropathy
cardiac abnormalities: arrhythmias, cardiac arrest
causes = kidney failure, meds, insufficient aldo secretion
Potassium deficiency
{ kypokalemia }
fatigue muscle weakness/cramps incr BP kidney stones arrhythmias
Conditions that incr risk for hypokalemia
potassium-wasting diuretics alcoholism severe vomiting/diarrhea laxative overuse anorexia/bulimia magnesium deficiency
Potassium food sources
potato avocado leafy greens nuts/seeds brassicas banana squash
Magnesium
75% of US pop = deficient
RDA = 420 mg/day (m) or 320 mg/day (f)
Magnesium functions
catalyst for ATP production
cell membrane stabilization (ion channel regulation)
synthesis of protein/lipids/nucleic acids
muscle contraction
blood clotting
BP regulation
Magnesium excess
supplements only diarrhea alkalosis dehydration impaired kidney function
Magnesium deficiency
neuromuscular excitability - incr intracellular Na and Ca; decr Mg and K muscle cramps/twitching restless leg syndrome cardiac dysrhythmias HTN N/V/D bone health effects
Magnesium in foods
whole grains leafy greens nuts/seeds legumes fish
Calcium
most abundant mineral in the body
2 forms = hydroxyapatite (bone/teeth) and ionized calcium (bodily fluids/physio activity)
AI = 1000 mg/day
UL = 2500 mg/day
Calcium absorption
Primary Route
proximal SI; 60% absorbed (400-500 mg)
3 Vit D dependent mechanisms:
1. calcium transporter 1 or TRPV6: saturable, requires ATP
2. calbindin: shuttles Ca across cytosol
3. Ca-ATPase: releases Ca into plasma on basolateral membrane
Other routes of Ca absorption
Paracellular diffusion
- when intestinal Ca concentration = high
claudins (vit D dependent transmembrane proteins)
enhanced by FOS, inulin, non-digestible saccharides
Bacterial digestion/fermentation of fiber releases bound Ca
= 4-10% of calcium absorbed in colon QD
Calcium absorption
25-30% from food
27-39% from supplements depending on salt used
- calcium citrate minimizes GI discomfort
intakes of
Inhibitors of calcium absorption
fiber - phytic and oxalic acids
excessive divalent cations - Zn, Mg
excretion incr by sodium, protein, caffeine
Methods of phytate reduction
cooking/heating soaking/sprouting fermenting processing vit c - 50 mg/meal good gut health - normal stomach pH reduces phytates
Calcium metabolism
transport via albumin/prealbumin (40%) or sulfate/phosphate/citrate (10%) or free/ionized (50%)
most = deposited in bone
intra/extracellular concentrations = tightly regulated (8.5-10.5 mg/dL)
Calcium functions
calcification of bones, teeth
blood-clotting activator of thrombokinase
transport of ions across cell membranes (nerves/muscles)
hormone secretion (insulin)
Calcium balance
regulated via PTH (raises blood Ca) and calcitonin (lowers blood Ca)
Calcium toxicity
rigor
Calcium deficiency
acute = tetany chronic = bone depletion/osteoporosis/stunted growth
causes = vit D deficiency, excess sodium, protein, caffeine
Calcium food sources
dairy leafy greens brassicas tofu fortified grains legumes seaweed
Phosphorus
2nd most abundant mineral in body
critical for bone formation - strength/rigidity
RDA = 700 mg/day
UL = 4,000 mg/day
Phosphorus functions
formation of: - bones/teeth - ATP - coenzymes like NADP nucleotide/nucleic acid structure biosynthesis of phospholipids in cell membranes carb metabolism (G6P and F6P)
Phosphorus excess
calcification of non-skeletal tissue, esp kidneys
risk for CVD and fracture
Phosphorus deficiency
muscle weakness
bone pain
Phosphorus food sources
dairy liver beef chicken eggs tofu legumes nuts/seeds
Sulfur
easily attainable from dietary proteins (met and cys)
needed for hair, skin, nail structure
no recommendations/limits set
Sulfur functions
ETC enzyme function/structure
insulin structure/function
detox: taurine, glutathione, cysteine, methionine
Sulfur deficiency
joint pain/arthritis
impaired liver function
no known excess
Sulfur food sources
eggs legumes whole grains garlic onions brassicas, esp brussels and cabbage
