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Minerals. Dr Reed Berger Nutrition Course Director Visiting Clinical Professor GI/Nutrition. General Lecture Format. -test questions will come from clinical correlations-- these will be relevant in clinical training and practice -items with *** and those with photos are important!!.

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Minerals

Minerals

Dr Reed Berger

Nutrition Course Director

Visiting Clinical Professor GI/Nutrition


General lecture format
General Lecture Format

  • -test questions will come from clinical correlations--these will be relevant in clinical training and practice

  • -items with *** and those with photos are important!!


Minerals1
Minerals

  • A naturally occurring , homogeneous, inorganic substance required by humans in amts of 100 mg/day or more

    • -functions

    • -high and low serum levels

    • -absorption

    • -excretion

    • -deficiency

    • -toxicity



Calcium1
Calcium

-most abundant mineral in the body

-99% of calcium is in the bones and teeth

-the remaining 1% is in the blood and ECF in cells and soft tissues


Skeletal calcium
Skeletal Calcium

-if there is no reserve, calcium is drawn from bone—leading to deficiency


  • Serum levels: 8.8 to 10.8 mg/dl

  • **when albumin is low (malnutrition, liver dz), calcium is decreased

  • Ratio: for each gram albumin is decreased below 4, add 0.8 to calcium



Functions
Functions alkalosis (increased bicarb binds calcium)

  • -building and maintaining bones and teeth

  • -transport fxn of cell membranes and membrane stabilizer

  • ***-nerve transmission and regulation of heartbeat—use calcium gluconate IV to treat hyperkalemia (EKG—peaked T waves)

  • -ionized form initiates formation of the blood clot

  • -cofactor in conversion of prothrombin to thrombin


Absorption
Absorption alkalosis (increased bicarb binds calcium)

  • -***absorbed mainly in the acidic part of the duodenum

  • -absorption is decreased in the lower GI tract which is more alkaline

  • 20-30% of digested calcium is absorbed

  • Absorption is thru 1,25 (OH)2D3 (vit D derivative)--stimulates production of calcium binding protein and alk phos

  • -unabsorbed form is excreted in feces


Factors that increase calcium absorption
Factors that increase calcium absorption alkalosis (increased bicarb binds calcium)

  • -***more efficiently absorbed when the body is deficient

  • -best absorbed in acidic environment (upper duodenum)

  • -HCL in stomach allows better absorption in the proximal duodenum

  • -taking calcium with food increases abs

  • -fat increases intestinal transit time and increases absorption


Factors that decrease absorption
Factors that decrease absorption alkalosis (increased bicarb binds calcium)

  • -***lack of vitamin D

  • -oxalic acid forms insoluble complex which decreases absorption (rhubarb, spinach, chard, beet greens)

  • -phytic acid found in outer husks of cereal grains also form insoluble complex

  • -alkaline medium decreases abs.(lower GI tract)

  • Aging decreases absorption


Maintenance of serum level
Maintenance of serum level alkalosis (increased bicarb binds calcium)

  • -parathormone (PTH) by the parathyroid gland and thyrocalcitonin secreted by the thyroid gland maintain serum levels

  • -***with decreased serum calcium levels, PTH increases and causes transfer of calcium from bone to blood to increase serum levels

  • -decreased levels also cause kidney to reabsorb calcium more efficiently (might normally be excreted in the urine) and to increase intestinal absorption

  • -when blood levels are increased, calcitonin acts by the opposite mechanisms as PTH to decrease serum levels


Maintenance of serum level cont d
Maintenance of serum level cont’d alkalosis (increased bicarb binds calcium)

  • ***-always need to correct low Mg level before treating a low calcium level

  • -hypomagnesemia decreases tissue responsiveness to PTH


Causes of hypocalcemia
Causes of hypocalcemia alkalosis (increased bicarb binds calcium)

-***malabsorption

-small bowel bypass, short bowel

-vit D deficiency

-alcoholism

-***chronic renal insufficiency

-***diuretic therapy


Causes of hypocalcemia cont d
Causes of hypocalcemia cont’d alkalosis (increased bicarb binds calcium)

-hypoparathyroidism

-***hypomagnesemia

-sepsis

-pseudohypoparathyroidism

-calcitonin secretion with medullary carcinoma of the thyroid


Causes of hypocalcemia cont d1
Causes of hypocalcemia cont’d alkalosis (increased bicarb binds calcium)

-***associated with low serum albumin (ionized calcium will be wnl)

-decreased end organ response to vit D

-hyperphosphatemia

-***aminoglycosides, plicamycin, loop diuretics, foscarnet


Causes of hypercalcemia
Causes of hypercalcemia alkalosis (increased bicarb binds calcium)

-milk-alkali syndrome

-vit D or vit A excess

-primary hyperparathyroidism

-secondary hyperparathyroidism (renal insuff, malabsorption)

-acromegaly

-adrenal insufficiency


Causes of hypercalcemia cont d
Causes of hypercalcemia cont’d alkalosis (increased bicarb binds calcium)

***Neoplastic Disease

-tumors producing PTH-related proteins (ovary, kidney, lung)

-***mets to bone

-lymphoproliferative disease including multiple myeloma

-secretion of prostaglandins and osteolytic factors


Causes of hypercalcemia cont d1
Causes of hypercalcemia cont’d alkalosis (increased bicarb binds calcium)

-***thiazide diuretic

-sarcoidosis

-paget’s disease of bone

-***immobilization

-familial hypocalciuric hypercalcemia

-complications of renal transplant

-iatrogenic


Excretion
Excretion alkalosis (increased bicarb binds calcium)

  • -normal is 65-70% of ingested calcium to be excreted in the feces and urine

  • -strenuous exercise increases loss (in sweat)

  • -***immobility with bed rest and space travel increase calcium loss because of lack of bone tension


RDA alkalosis (increased bicarb binds calcium)

  • -see handout


Sources
sources alkalosis (increased bicarb binds calcium)


Deficiency
Deficiency alkalosis (increased bicarb binds calcium)

  • 1)***bone—to be discussed in osteoporosis lecture

  • 2) tetany—decreased serum levels increase the irritability of nerve fibers resulting in muscle spasms, fatal laryngospasm

    • ***-Chvostek’s sign: contraction of the facial m. after tapping the facial n.

    • ***-Trousseau’s sign: carpal spasm after occlusion of the brachial a. with blood pressure cuff for 3 min

  • 3) HTN—controversial

  • 4) prolonged QT--arrythmias


Toxicity
Toxicity alkalosis (increased bicarb binds calcium)

  • -***polyuria, constipation, bone pain, azotemia, coma

  • -”stones, bones(bone pain), groans, psychiatric overtones”


Phosphorus
Phosphorus alkalosis (increased bicarb binds calcium)

  • Levels maintained by parathyroid gland


Functions1
Functions alkalosis (increased bicarb binds calcium)

  • -structure of teeth and bones

  • -essential component in cell membranes, nucleic acids, phospholipids

  • -phosphorylation of glucose

  • -buffer system in ICF and kidney


Absorption1
absorption alkalosis (increased bicarb binds calcium)

-best occurs when calcium and phos are ingested in equal amts (milk)

-vit D also increases absorption


RDA alkalosis (increased bicarb binds calcium)

  • -see table (and for all RDA’s)


Sources1
sources alkalosis (increased bicarb binds calcium)


Sources2
Sources alkalosis (increased bicarb binds calcium)

***dietary sources should be restricted in renal disease (usually see increased phos, decreased Ca)

  • -protein sources

  • -meat, poultry, fish, eggs, legumes, nuts, milk, cereals, grains


Renal disease
Renal Disease alkalosis (increased bicarb binds calcium)


Causes of hypophosphatemia
Causes of hypophosphatemia alkalosis (increased bicarb binds calcium)

-starvation

-TPN with inadequate phos content

-malabsorption, small bowel bypass

-vit D deficient and vit D resistant osteomalacia


Causes of hypophosphatemia cont d
Causes of hypophosphatemia cont’d alkalosis (increased bicarb binds calcium)

-phosphaturic drugs: theophylline, diuretics, bronchodilators, corticosteroids

-hyperparathyoidism (primary or secondary)

-hyperthyroidism

-renal tubular defects

-hypokalemic nephropathy

-inadequately controlled DM

-***alcoholism


Causes of hypophosphatemia cont d1
Causes of hypophosphatemia cont’d alkalosis (increased bicarb binds calcium)

Intracellular shift of phosphorus

-administration of glucose

-anabolic steroids, estrogen, OCP

-respiratory alkalosis

-salicylate poisoning

Electrolyte abnormalities

-hypercalcemia

-hypomagnesemia

-metabolic alkalosis


Causes of hypophosphatemia cont d2
Causes of hypophosphatemia cont’d alkalosis (increased bicarb binds calcium)

Abnormal losses followed by inadequate repletion

-***DM with acidosis—with aggressive therapy

-***recovery from starvation or prolonged catabolic state—refeeding syndrome

-***chronic alcoholism, especially with nutritional repletion, assoc with hypomagnesemia—”

-recovery from severe burns


Causes of hyperphosphatemia
Causes of hyperphosphatemia alkalosis (increased bicarb binds calcium)

-excessive growth hormone (acromegaly)

-hypoparathyroidism assoc with low Ca

-pseudohypoparathyroidism assoc with low Ca

-***chronic renal insufficiency

-acute renal failure


Causes of hyperphosphatemia cont d
Causes of hyperphosphatemia cont’d alkalosis (increased bicarb binds calcium)

Catabolic states, tissue destruction

-stress or injury, rhabdomyolysis (esp with renal insufficiency)

-chemotherapy of malignant disease, particularly lymphoproliferative disease

Excessive intake or absorption

-laxatives or enemas containing phosphate

-hypervitaminosis D


Deficiency1
Deficiency alkalosis (increased bicarb binds calcium)

  • -fatal

  • -usually rare with food intake

  • -***respiratory muscle collapse

  • -heart failure

  • -muscle aches, bone pain, and fracture


Toxicity1
Toxicity alkalosis (increased bicarb binds calcium)

  • -symptoms of the primary disorder


Magnesium
Magnesium alkalosis (increased bicarb binds calcium)


Function
Function alkalosis (increased bicarb binds calcium)

-bone, muscle contractility, nerve excitability

-antagonistic to calcium

--in a muscle contraction, Mg relaxes, and calcium contracts

--low Mg can cause pregnancy induced HTN


Absorption excretion
Absorption / Excretion alkalosis (increased bicarb binds calcium)

  • -absorption varies

  • -similar to calcium (low pH, upper GI), however, no Vit D required-kidney conserves Mg when intake of Mg is low

  • -large losses with vomiting because of high levels of gastic juice


Sources3
sources alkalosis (increased bicarb binds calcium)


Sources4
Sources alkalosis (increased bicarb binds calcium)

  • -seeds, nuts, legumes, unmilled cereal grains, dark greens

  • -fish, meat, milk, fruits

  • -lost during refining of flour, rice, vinegar


Causes of hypomagnesemia
Causes of hypomagnesemia alkalosis (increased bicarb binds calcium)

-malabsorption, chronic diarrhea, laxative abuse

-prolonged GI suction

-small bowel bypass

-malnutrition

-***alcoholism

-refeeding

-TPN with inadequate Mg


Causes of hypomagnesemia cont d
Causes of hypomagnesemia cont’d alkalosis (increased bicarb binds calcium)

-DKA

-diuretics

-hyperaldosteronism, Barrter’s syndrome

-hypercalcuria

-renal Mg wasting

-hyperparathyroidism

-postparathyroidectomy

-vit D therapy

-aminoglycosides, ***cisplatin, ampho B


Causes of hypermagnesemia
Causes of hypermagnesemia alkalosis (increased bicarb binds calcium)

Decreased renal fxn

***Increased intake—abuse of Mg containing antacids (MOM) and laxatives in renal insufficiency


Deficiency2
Deficiency alkalosis (increased bicarb binds calcium)

  • -anorexia, growth failure, cardiac and neuromuscular changes—weakness, irritability, mental derangement

  • -tetany, muscle cramps


Toxicity2
Toxicity alkalosis (increased bicarb binds calcium)

  • -respiratory—depression, apnea

  • -CV—hypotension, cardiac arrest, EKG (prolonged QRS and QT, heart block, peaked T waves)

  • -GI—N/V

  • -neuromuscular—paresthesias, somnolence, confusion, coma, hyporeflexia, paralysis, apnea


Iron alkalosis (increased bicarb binds calcium)


Function1
Function alkalosis (increased bicarb binds calcium)

  • -respiratory transport of O2 and CO2

  • -immune system

  • -cognitive performance

  • -found in Hgb (in RBC’s) and myoglobin (in muscles)

  • -cytochrome p450 system


Absorption and transport
Absorption and transport alkalosis (increased bicarb binds calcium)

  • -dietary iron exists in heme (Hgb and myoglobin) and non-heme

  • -***heme Fe is absorbed better

  • -non-heme Fe has to be present in the duodenum or upper jejunum in soluble form if it is to be absorbed

  • -in Fe deficiency, 50% can be absorbed

  • -***2-10% of Fe from veggies is absorbed and 10-30% is absorbed from animal protein


Factors affecting absorption
Factors affecting absorption alkalosis (increased bicarb binds calcium)

  • -***ascorbic acid is the most potent enhancer

  • -animal proteins (beef, pork, veal, lamb, liver, fish, chicken) enhance

  • -but, proteins from cow’s milk, cheese, eggs, don’t

  • -gastric acidity enhances absorption (antacids interfere)

  • -pregnancy, increased growth, Fe defic all increase deficiency


  • -phytate and tannins decrease abs alkalosis (increased bicarb binds calcium)

  • -Fe used for enrichment are less absorbed than elemental Fe

  • -increased intestinal motility decreases absorption because it decreases contact time for absorption


Storage
Storage alkalosis (increased bicarb binds calcium)

  • -stored as ferritin and hemosiderin

  • -long term high Fe ingestion or frequent blood transfusions can lead to accumulation of Fe in the liver

  • -***hemosiderosis develops in individuals who consume a lot of Fe or have a genetic defect resulting in increased Fe absorption

  • -in associated with tissue damage, it is called hemochromatosis


Excretion1
Excretion alkalosis (increased bicarb binds calcium)

  • -lost thru bleeding, feces, sweat, exfoliation of hair and skin

  • -none in urine


Sources and intakes
Sources and Intakes alkalosis (increased bicarb binds calcium)

  • -best source is liver

  • -oysters, shellfish, kidney, lean meat, poultry, fish

  • -dried beans, veggies, dark molasses

  • -egg yolks, dried fruit, enriched breads,

  • -requirements are highest in infancy and adolescence

  • -females stay high because of menstruation

  • -decrease with menopause and increased with pregnancy


Deficiency3
Deficiency alkalosis (increased bicarb binds calcium)

  • -most common deficiency

  • -most at risk: <2 yrs old, teens, pregnancy, elderly

  • -***anemia (hypochromic, microcytic)

  • -tx: diets high in absorbable Fe and/or Fe supplements (ferrous sulfate, ferrous gluconate)

  • -can be caused by injury, hemorrhage, illness, poor diet


Zinc alkalosis (increased bicarb binds calcium)

  • -involved in synthesis or degradation of CHO, proteins, lipids, nucleic acids

  • -stabilizes RNA and DNA

  • involved in transcription and replication

  • -needed for bone enzymes and osteoblastic activity


Absorption2
absorption alkalosis (increased bicarb binds calcium)

  • Impaired absorption in Crohn’s or pancreatic insufficiency

  • -plasma zinc levels act as acute phase reactants and fall by 50% with injury (like platelets)


Inhibiting factors
Inhibiting Factors alkalosis (increased bicarb binds calcium)

  • -fiber, phytate

  • -high doses of copper

  • -Fe competes with zinc for absorption


Enhancing factors
Enhancing Factors alkalosis (increased bicarb binds calcium)

  • -glucose, lactose, and soy protein

  • -red wine

  • -human milk


Excretion2
Excretion alkalosis (increased bicarb binds calcium)

  • -feces—almost entirely

  • -***in urine with starvation, nephrosis, DM, alcoholism, hepatic cirrhosis (zinc supplementation in encephalopathy), porphyria


Sources and intakes1
Sources and Intakes alkalosis (increased bicarb binds calcium)

  • -meat, fish, poultry, milk

  • -oysters, shellfish, meat, liver, cheese, whole grains, dry beans, nuts


Deficiency4
Deficiency alkalosis (increased bicarb binds calcium)

  • -short stature, hypogonadism, anemia

  • -with diets high in unrefined cereal and unleavened bread

  • -delayed wound healing, alopecia

  • ***-acrodermatitis enteropathica=AR dz with zinc malabsorption

  • -eczematoid skin lesions, alopecia, diarrhea, bacterial and yeast infections, death



Causes of deficiency
***Causes of deficiency alkalosis (increased bicarb binds calcium)

  • Anorexia Nervosa

  • TPN without zinc (diarrhea, small bowel fistulas)

  • High intake of phytate, tannins, binding drugs (EDTA), oxalate

  • High iron intake

  • Malabsorption syndromes

  • Acrodermatitis enteropathica

  • Diarrhea

  • Pancreatico-cutaneous fistula

  • Proximal entero-cutaneous fistulas

  • Hemolytic anemias (sickle cell anemia)

  • Renal failure patients on dialysis


Zinc deficiency
***Zinc Deficiency alkalosis (increased bicarb binds calcium)

42 yo female with chronic uremia on dialysis. Recently started on iron supplement for anemia. Presents with rash, hypogeusia, hyposmia and poor dark adaptation.


Acrodermatitis enteropathica
Acrodermatitis Enteropathica alkalosis (increased bicarb binds calcium)

  • Autosomal recessive disease associated with a defect causing a reduction in zinc absorption

  • Can be treated by pharmacologic doses of oral zinc


Acrodermatitis enteropathica1
Acrodermatitis Enteropathica alkalosis (increased bicarb binds calcium)


Toxicity3
Toxicity alkalosis (increased bicarb binds calcium)

  • ->100-300 mg/d

  • -rare

  • -interferes with copper absorption

  • -decrease in HDL

  • -GI irritation, vomiting


Fluoride
Fluoride alkalosis (increased bicarb binds calcium)

  • -tooth enamel

  • -resistance to dental caries

  • -fluoridation of h20 has decreased caries by half

  • -found in drinking h20, teflon pots and pans (cooked in these)

  • -toxicity at doses >0.1 mg/kg/d


Prevention of dental caries
Prevention of dental caries alkalosis (increased bicarb binds calcium)

  • ***Incidence of dental fluorosis (mottled teeth) occurs with increased intake above 1-2 ppm.

  • Intervention studies have demonstrated water supplementation reduces prevalence of caries


Mottled teeth in fluorosis alkalosis (increased bicarb binds calcium)


Maganese
Maganese alkalosis (increased bicarb binds calcium)

  • -found in many enzymes

  • -connective and bony tissue formation

  • -growth and reproduction

  • -CHO and lipid metabolism


Absorption and excretion
Absorption and Excretion alkalosis (increased bicarb binds calcium)

  • -after absorption, it appears rapidly in the bile and is excreted in the feces

  • -concentrated in liver and increases with liver disease


Sources and intakes2
Sources and Intakes alkalosis (increased bicarb binds calcium)

  • -whole grains, legumes, nuts, teas, fruit, veggies, instant coffee, and tea


Deficiency5
Deficiency alkalosis (increased bicarb binds calcium)

  • -wt loss, ataxia, dermatitis, N/V, decreased hair growth, impaired reproductive activity, decreased pancreatic function and CHO metabolism


Toxicity4
Toxicity alkalosis (increased bicarb binds calcium)

  • -accumulates in liver and CNS—parkinsonian sx


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