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Causes vasodilatation
Decreases peripheral vascular resistance
Balance - closely related to K and Ca balance
Intracellular compartment electrolyte
Hypomagnesemia - < 1.5 mEq/L
Hypermagnesemia - > 2.5 mEq/L
chronic alcoholism
Acute pancreatitis, starvation, malabsorption syndrome, _______, burns, prolonged hyperalimentation without adequate Mg
Hypoparathyroidism with hypocalcemia
Diuretic therapy
Signs/Symptoms hypomg
Tremors, tetany, ↑ reflexes, paresthesias of feet and legs, convulsions
Positive Babinski, Chvostek and Trousseau signs
Personality changes with agitation, depression or confusion, hallucinations
ECG changes (PVC'S, V-tach and V-fib
Treatment hypomg
Diet - Best sources are unprocessed cereal grains, nuts, legumes, green leafy vegetables, dairy products, dried fruits, meat, fish
Magnesium salts
More severe
MgSO4 IV slowly
Approximately 99% found in bone, 1% found in extracellular fluid
50% free (active) ionized form (1-1.15 mmol/L)
40% bound to protein (predominantly albumin)
10% complexed with anions (eg, citrate)

Intracellular calcium regulates cAMP - mediated messenger systems and most cell organelle functions
Ion pumps control lvels
Extracellular levels maintained at 8.7-10.4 mg/dL
Total body levels controlled by complex feedback system
PTH directly targets bone and kidneys to increase serum calcium levels
Indirectly, through vitamin D, PTH causes intestinal calcium absorption
Vitamin D directly targets GI absorption of calcium to increase calcium levels
Calcitonin lowers calcium by targeting bone, renal, and GI losses
90% due to hyperparathyroidism or malignancy
All etiologies due to a combination of increased bone resorption, increased GI absorption, and decreased renal excretion
Primary hyperparathyroidism mostly commonly due to adenoma; occasionally due to parathyroid hyperplasia; rarely due to parathyroid carcinoma
Paresthesias, tetany (especially carpopedal spasm)
Lethargy, confusion, seizures
Trousseau's sign (carpal spasm occurring after the occlusion of the brachial artery with a blood pressure cuff for three minutes)
Chvostek's sign (contraction of the facial muscle in response to tapping the facial nerve anterior to the ear)
QT prolongation
Severe, symptomatic _______ may result in cardiovascular collapse, hypotension unresponsive to fluids & vasopressors, and dysrhythmias
Clinically evident _____ generally presents in milder forms and is usually the result of a chronic disease state
PhosphorusFunctions of phosphorus
The major intracellular negatively charged electrolyte
Required for fluid balance
Critical role in bone formation (85% of body's phosphorus is found in bone)
Regulates biochemical pathways by activating or deactivating enzymes
Found in ATP, DNA, RNA
Recommended intake
RDA for ____ is 700 mg/day

Sources of ____
Found widespread in many foods
Found in high amounts in foods that contain protein (e.g., meat, milk, eggs)
What if you consume too much ___?
High blood levels of ____ can occur with kidney disease or when taking too many vitamin D supplements
Causes muscle spasms, convulsions

What if you don't consume enough ___?
Deficiencies of ___ are rare
Seen in severe alcoholism
-body normally has 20-30 mg of ___ and more than 75% is in the thyroid gland
-the rest is in the mammary gland, gastric mucosa, and blood
-it's only function is related to thyroid hormone

Required for synthesis of thyroid hormone
Thyroxine (T4) - 4 atoms of__ per molecule
Triiodothyronine (T3) - 3 atoms of__ per molecule
Absorption and Excretion
-iodine is absorbed in the form of iodide
-occurs both as free and protein-bound iodine in circulation
-iodine is stored in the thyroid where it is used for the synthesis of T3 and T4
-the hormone is degraded in target cells and in the liver and the iodine is conserved if needed
-excretion is primarily via urine
-small amts from ___are excreted in the feces
Deficiency iodine
goiter—enlargement of the thyroid gland
-deficiency may be absolute—in areas of deficiency, or relative—adolescence, pregnancy, lactation
-goiters are more prevalent in women and with increased age
-goitrogens occurring naturally in foods can cause goiter by blocking absorption or utilization of iodine (cabbage, turnips, peanuts, soybeans)
-***severe deficiency during gestation and early postnatal growth: ______ —mental deficiency, spastic diplegia, quadriplegia, deaf mutism, dysarthria, shuffling gait, short stature, hypothyroidism
_________deficiency is the most common nutrient deficiency in the world!
Paradoxical goiter
Iodine Excess and Toxicity
Humans are remarkably tolerant to high iodine intakes
In iodine deficiency, repletion must be done slowly to prevent hyperthyroidism
_______(enlarged thyroid as a result of very high intakes of iodine)
Occurs in Japan and China with high intake of seaweed (50,000 - 80,000 mg/day)
-iodine has wide margin of safety
Selenium deficiency
Endemic to parts of S. America and India
Sporadic cases in U.S.
___________ (needed to convert T4 to T3
Copper Metabolism
Intestinal absorption/membrane translocation mediated by specific transporters
Copper circulates bound to _____
Relative tissue distribution of copper reflects levels of cuproenzymes
Excretion occurs via transport of copper into bile and elimination in feces
Copper: Biochemical Functions
Essential catalytic cofactor for many cuproenzymes
Hypochromic microcytic anemia
Hypopigmentation of hair and skin
Structural abnormalities in connective tissue (hair, teeth, bone demineralization, vascular system with arterial aneurysms with risk of hemorrhage and thrombosis)
Fetal and neonatal deprivation leads to neurologic dysfunction
Reduced levels of circulating copper and ceruloplasmin
Copper Physiology/Deficiency
Acquired deficiency is rare. Causes include:
Omission from TPN
High intake of Zinc
Renal dialysis patients
Use of copper chelating agents (penicillamine)
Food Sources copper
organ meats, seafood, nuts, seeds, cereals, whole grains, cocoa
-required for normal lipid and CHO metabolism and for the fxn of insulin
-?can supplementation raise HDL
Deficiency chromium
altered CHO metabolism, impaired glucose tolerance, glycosuria, fasting hyperglycemia, increased insulin levels and decreased insulin binding
-impaired growth, peripheral neuropathy, negative nitrogen balance
-increased chromium losses in stress
-hyperglycemia and wt loss reverse with IV supplementation in TPN
chromium toxicity
-chronic renal failure
most stored with vitamin B12
-component of B12—cobalamin
-essential for maturation of RBC's and normal function of all cells
Absorption and Excretion cobalt
-shared with Fe
-absorption is increased in pts with deficient Fe intake, portal cirrhosis with Fe overload, and hemochromatosis
-excretion is mainly thru the urine
-small amts in feces, hair, sweat
animal foods such as organ and muscle meat
Sources and Intakes cobalt
-microorganisms are able to synthesize B12
-***humans must obtain B12 and cobalt from _______________
-***takes a long time to become deficient—happens in vegetarians
macrocytic anemia
Deficiency cobalt
-related to vit B12 deficiency
-genetic defect: pernicious anemia
-tx: massive doses
Toxicity cobalt
-hyperplasia of BM
-increased blood volume
glutathione peroxidase
-acts with other antioxidants and free radical scavengers
-overlaps with vit E for antioxidant effects
-fxn with vit E to protect cell and organelle membranes from oxidative damage
Selenium Deficiency Diseases
Major problem in livestock
Human deficiency is rare except in areas with low Se content in soil
Keshan disease occurs in Keshan China: endemic cardiomyopathy and muscle weakness (due to oxidized lipids)
Aggressive supplementation has eliminated disease
Iatrogenic deficiency
TPN without supplemental Se
Selenium Toxicity
Range of dietary Se intake without toxicity is narrow
Acute selenium poisoning can result in cardiorespiratory collapse (gram amounts)
Chronic toxicity (selenosis) changes in nail structure and loss of hair (intakes ~6x UL)
Hair and nail brittleness
Selenium and Cancer Prevention
Epidemiologic evidence indicates low intakes of Se are associated with higher risk of prostate cancer
Prospective study of Se supplementation demonstrated 42% reduction in cancer incidence
Small sample size and other confounding factors have diminished enthusiasm for the results of these studies
-relationship with copper and sulfate
-cofactor of many enzymes involved in the catabolism of sulfur AA, purines and pyridines
-Toxicity: gout-like syndrome, reproductive SE's
-Deficiency: increased risk with co-existing copper deficiency, TPN
Normal: 136-145 mEq/L or mmol/L
Critical values:
Na < 125
Na >160
Na level is major determinant of osmolality
Serum osmolality
_____________-2 x Na + BUN/3 + glucose/18; you calculate this -Usually in range of 280-290
It is driven by sodium
Severe acute hyponatremia (<120 over <24 Hours): cerebral edema
Hyponatremia: symptoms
Most patients are asymptomatic
Symptoms usually occur with [Na+] < 125
Nausea, vomiting, headache
Seizures, coma, respiratory arrest
reduced in wilsons (ring in eye)