Lecture 7 NFS382 Hypertension and Microminerals
Sodium
•Major source: added NaCl
•1 tsp salt ~2.3g Na
•Salt free = <5mg NaCl/serving
Reduced salt/less salt: 25%+ less NaCl/serving than reference
Sodium Absorption, Transport
•Most is absorbed
•Little excreted in feces
•BBM
oNa/glucose cotransporters in SI
oNa/Cl cotransporters in SI, colon
oNa absorption in colon
•In blood: transport free Na
Sodium Function
•Serum Na, K, Cl narrow range (electrolyte balance); maintain osmotic pressure,
fluid balance
•Nerve transmission, muscle contraction (AP)
•Na: extracellular cation
Blood Pressure: force blood exerts against walls of blood vessels, measured mmHg
oE.g. 124/84 (systolic/diastolic pressure)
oSystolic: heart beats, pumps blood
oDiastolic: heart relaxes, fills with blood
oDecrease in blood pressure by 10/5mmHg has benefits: Decreased heart
failure, stroke, heart attack, death
oNormal blood pressure
Healthy <120/80
Kidney disease/diabetes <130/80
Sodium increases blood pressure
Increased Na/Decreased renal Na excretion/Increased Na reabsorption NaCl/H20
retention Increased plasma volume increased blood pressure
Na interferes with blood vessel smooth muscle activity, promotes muscle contraction
K, Ca counterbalance Na effects
Potassium
•Major intracellular cation
•Unprocessed foods: bananas, mango, papaya, leafy greens, etc.
•85%+ absorbed
•K diffusion channels in BLM of enterocytes
•90% excretion in urine