Lecture 13 - Minerals, Sodium, Potassium, Hypertension

major minerals

sodium, potassium, calcium, phosphorus, magnesium

trace minerals/elements

iodine, iron, zinc, copper, manganese, chromium

electrolytes

maintain fluid balance, potassium is the major cation in the cell and sodium is the major cation outside the cell, the Na-K-ATPase pump maintains the balance

CDRR

chronic disease risk reduction intake, to determine it for a nutrient that reduces risk with increased intake, the literature would be reviewed to determine intake that is linked to meaningful reduction in disease risk, for those that increase risk with increasing intake, an upper limit for a nutrient can be set, an intake above which the risk of disease noticeably increases

sodium

only nutrient with a CDRR (2300 mg), intake above will increase risk of disease noticeably, it replaces the UL because the old UL (2300 mg) was based on hypertension, it has an AI of 1500 mg for all adults

sodium AI (adequate intake)

for those between 19 and 50 yrs old its 1500 mg, for those between 50 and 70 its 1300mg and for those above 70 its 1200 mg

potassium

the AI is 4700 mg (population has an adequate intake if over 50% of the population has an intake greater than the AI, if its less than 50% then population intake may or may not be adequate

potassium AI

for men over 19 yrs old its 3400 mg and for women over 19 yrs old its 2600 mg

blood pressure

sodium and potassium have counterbalancing effects on blood pressure so sodium increases it and potassium decreases it, foods high in calcium and magnesium also lowers blood pressure

hypertension

salt sensitivity and high sodium intake, causing increased blood pressure, it causes fluid retention with increased blood volume and pressure

health claim for sodium and potassium

a 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

DASH eating plan

diet high in foods that contain potassium, calcium and magnesium, high in dairy products and vegetables, it lowers blood pressure and the effect is more dramatic the higher the sodium content was prior

calcium

structure to bones and health, levels in the blood must be maintained in a very narrow range, when the levels in the blood are too low, it is taken from the bone and overtime can lead to osteoporosis

calcium absorption

vitamin D promotes synthesis of calcium transport proteins, it is carried across enterocyte and the pump that requires energy moves it into the blood

calcium absorption rates

in infants absorption is highest at 60% to absorb calcium for bone and it decreases with time, in adults its 25% to 30%, adults that have a vit D deficiency absorb very little calcium (10%), during pregnancy absorption increases so that RDA for calcium in pregnancy is unchanged

calcium bioavailability

it is decreased by tannins, fibre, phytates and oxalates, vegetables low in oxalate are food sources of calcium (kale, collard greens, turnip greens, mustard greens and chinese cabbage)

non bone related functions of calcium

muscle contraction, neurotransmitter release, required for blood clotting, blood pressure regulation, there is an inverse association between calcium intake and colon cancer and the reasoning behind it is that it binds to toxins in the colon making them insoluble and biologically inactive

mineral component of bone

hydroxyapatite makes up the inorganic matrix, Ca5(PO4)3OH allows for mineral, strength and rigidity, protein is made of collagen (organic matrix, hydroxyapatite deposits on protein and provides flexibility)

osteoblast

bone forming

osteoclast

bone breaking/resorption

osteoporosis

loss of both protein (organic matrix) and inorganic matrix (mineral/hydroxyapatite) components from bone

osteoporotic spine

when weakened by osteoporosis, the front edge of the vertebrae collapses more than the back edge so the spine bends forward, the trabecular bone is crushed, decline in height

estrogen

stimulates osteoblast activity/bone formation

accretion

uptake and accumulation of calcium from the diet

age related bone loss

in growing women, total bone mass increases as the bones grow larger, during puberty bone mass increases rapidly and sex differences in bone mass appear, men acheive a higher peak bone mass than women do, both men and women lose bone slowly after about age 35, in women bone loss is accelerated for about 5 years after menopause (osteoclast activity exceeds osteoblast activity), maximize peak bone mass when you are young so you dont cross the fracture threshold as you age, maintain calcium and vitamin D intake over lifetime to reduce the rate of bone loss

preventing and treating osteoporosis

maximizing dietary calcium and vitamin D reduces the rate of bone loss, exercise puts stress on bone stimulating mineralization

phosphorus

deficiency is very rare

magnesium

part of inorganic matrix of bone, needed for vitamin D function