Minerals - Ca, Mg, P, Na Flashcards
99% of the calcium in the body is stored in ____________.
The remaining 1% is found in the ____________________.
- The skeleton, including bones and teeth.
- Blood, muscles, and tissues.
Calcium exists in the serum in 3 forms (name them and give percentages).
- Protein bound (albumin or globulin) - 40%
- Chelated - 9%
- Free (Ionized) - 51% (able to be used)
Calcium in the blood, muscle, and other tissues is used for (3 things)_____________________________________.
Enzyme activation, blood clotting, and muscle contraction.
Normal range for serum total calcium on a lab is: __ - __
8.5-10.5 mg/dL
(Normal range in serum for ionized calcium = 4.5-5.5 mg/dL
Calcium levels in the body are regulated by _____ (4 answers)
Parathyroid hormone, vitamin D, phosphorus, and calcitonin
Calcium is regulated in (3 locations)______
Kidney, bone, and GI tract
__________ stimulates calcium absorption in the GI tract, while ____________ inhibits it.
vitamin D, phosphorus
Ionized calcium is affected by _______.
Ph levels. As serum pH rises calcium binds with protein.
What are the 6 functions of calcium?
- Bone mineralization (calcium levels change constantly throughout the day - moving 250-1000mg in and out of bone tissue)
- Maintenance of cell membrane permeability
- Muscle contraction
- Blood clotting
- Nerve impulse conduction
- Blood pressure regulation
Magnesium competes with _______ for absorption.
Calcium.
Vitamin D enhances Mg absorption
Magnesium is found in _________(4 places).
Intracellular and extracellular fluid, bone, and muscle.
The _________is the principal modulator of Mg homeostasis.
The kidney. Through filtration and reabsorption.
Only _____% of the bodys Mg pool is found in the blood.
1%.
And Mg is a co-factor for more than 300 enzymatic reactions
Mg is absorbed in the ________ (2 places).
Distal jejunum, and ileum.
Mg is more efficiently absorbed when intake is _______.
Low
Magnesium functions (list 6).
- Suppresses PTH secretion (though Calcium is better at this).
- Protein synthesis
- Cell replication
- Neural impulse transmission (along with calcium, sodium, and potassium).
- Component in bones and teeth.
- In ATP requiring reactions for metabolism and active transport (chelates ATP and ADP molecules).
Mg deficiency is _____, though average intake of magnesium is ______.
rare (due to presence in wide variety of foods).
lower than what it should be (on average 100mg less than RDA for men and 80mg less for women).
What is some of the main mechanisms and role of sulfur?
integral part of glutathione, insulin, keratan and other glycosaminoglycans in skin, cartilage, and connective tissue, serves as a site for attachment and transfer of single carbon methyl groups, is a component of many coenzymes
Mg deficiency can occur in people with _______ or _______ problems.
Absorption, excretion. Including: intestinal malabsorption, surgical removal of lower part of intestine, diuretic medications, vomiting, kidney disease, chronic alcohol abuse, hyperparathyroidism, and liver cirrhosis.
Symptoms of Mg deficiency (list 10).
Fatigue, lethargy, weakness, poor appetite, impaired speech, anemia, irregular heartbeat, tremors, and failure to thrive.
(Clinical signs = rapid heart rate, cardiac fibrillation, and convulsions).
Low levels of calcium and potassium in the blood can indicate a ____________ deficiency.
Magnesium.
Magnesium toxicity is most common in __________.
Renal failure. Also - watch for high doses of magnesium supplements.
Symptoms of magnesium toxicity include (6):
diarrhea, muscle weakness, nausea, extremely low blood pressure, difficulty breathing, irregular heartbeat.
Magnesium is required for normal _____ functioning.
PTH. Therefore mg levels may alter calcium and phosphorous homeostasis (PTH raises calcium in blood by pulling it from bone and increasing absorption in the GI tract.
Food sources of magnesium
Whole grains, leafy greens, nuts & seeds (especially pumpkin seeds, cashews, almonds, and flaxseeds), legumes, and dark chocolate.
(tip - foods high in fiber are high in Mg. When you think Mg, think fiber!)
The tolerable upper limit for magnesium has been established at ______mg/day for adults and adolescents.
350mg/day
Clinical uses for Mg.
Bowel preparation (for medical procedures), constipation, indigestion, seizures in women with eclampsia, pre-eclampsia preventative for eclampsia, asthma, diabetes/pre-diabetes, chronically low levels of potassium or calcium, malabsorptive diseases (such as celiac), pts taking diuretics, and elderly, mild hypertension, migraine headaches.
When taken with _____ and ______, Mg supplementation can improve insomnia in older individuals.
Zinc, melatonin.
Normal lab values for Mg are ___________.
1.5-2.3 mg/dl mg/dL.
Magnesium can decrease the absorption and effectiveness of numerous medications, including:
Some antibiotics (ie: cipro, minocycline, doxycyline), statins such as resuvastatin (crestor), and atorvastatin (lipitor), gabapentin, and levothyroxine.
Low magnesium intake has been correlated with __________________(5 conditions).
Hypertension, cardiovascular disease, osteoporosis, metabolic syndrome, and type 2 diabetes.
What are some food sources of sulfur?
beef, dried beans and peas, peanut butter and wheat germ
What is the role of tin?
a component of the respiratory electron transport chain and can interfere with porphyrin biosynthesis and enhance heme breakdown
What is the main role of cobalt?
intrinsic part of the active site of vitamin B12 (hence the alternative name, cobalamin).
Adenosylcobalamin (the activated form of the vitamin) is required for the conversion of methionine from homocysteine and of methylmalonyl-CoA to succinyl-CoA.
Food sources of cobalt include?
meats and animal foods.
Chronic exposure of ___________ (mineral) can lead to toxicity, causing diminished tissue respiration, inhibited glycolytic utilization of glucose by
erythrocytes, mottled teeth and skeletal deformations.
Fluorine
What are foods sources of fluorine?
seafood, tea leaves, water in some areas, meats, poultry and whole grains
What is the main roles of fluorine?
- prevents anemia of pregnancy
- reduces the formation of acid in the mouth caused by carbohydrates- —
- contributes hardening to tooth enamel
- contributes to stability of bone matrix
- is required for growth and fertility
What foods give us exposure to tin?
contamination from tin cans and other food packaging
Intake of chromium below 30 μg/day has been associated with decreased
skeletal mass
Primer Q #80
The daily calcium requirements of postmenopausal women who are not receiving estrogen replacement therapy are approximately:
1,500 mg of calcium as calcium carbonate
Primer Q #81
The daily calcium requirements of postmenopausal women who are not receiving estrogen replacement therapy can be met by the daily consumption of how many cups of skim milk?
5 cups
Primer Q #82
Reduced consumption of salt and salty foods may
reduce blood volume and blood pressure
Primer Q #83
What is the second most abundant mineral in the body?
Phosphorus
Phosphorous is present in the body mostly in ___ and ___
85% of phosphorus exists in BONES and TEETH as hydroxyapatite
Phosphorous is absorbed in the form of _____ mostly in the ____ _____
Absorbed as phosphate, mostly in the small intestine
Hark, p. 73
______-______ antacids can reduce phosphate absorption
aluminum-containing antacids (forms aluminum-phosphate complex and can’t be absorbed)
Hark, p. 73
What are the 6 main functions of phosphorus?
- Structural component of bones & teeth
- Energy synthesis (ATP, ADP)
- DNA and RNA synthesis (structural component of nucleic acids)
- Metabolism of proteins, fat and carbs (component of digestive enzymes)
- Maintenance of the body’s normal pH levels (acts as buffer)
- Normal cell membrane structure (structural component of phospholipids)
Hark, p. 73
Hypophosphatemia is rare, but can occur in which circumstances?
- Alcoholics
- Diabetic ketoacidosis
- Excessive consumption of aluminum-containing antacids
- Refeeding syndrome
- Hyperparathyroidism
Hark, p. 73
Symptoms of phosphorus deficiency include:
- Weakness (d/t decreased ATP & anorexia)
- Bone pain / fragility (rickets or osteomalacia in prolonged cases)
- Muscle weakness (proximal muscle myopathy)
Hark, p. 74
Phosphorous is typically highest in food sources of which macronutrient?
Protein sources
Top 10 food sources of phosphorous
Dairy, (yogurt, cheese, milk), meat (beef), poultry (chicken, turkey), salmon, halibut, eggs, lentils, almonds, peanuts, bread
Plant sources of phosphorous are ___% less bioavailable due to ___
50% less bioavailable due to phytates (humans don’t have the enzyme phytase needed to digest)
Hyperphosphatemia can occur in which conditions?
Renal failure and hypoparathyroidism
The TUL for phosphorus is:
4,000 mg/day
The main side effect of hyperphosphatemia is:
calcification of soft tissues - especially the kidneys (nephrocalcinosis)
Which are the 3 main hormones that regulate phosphorous absorption?
- Calcitriol (1, 25-dihydroxyvitamin D - the active form of vit D)
- Parathyroid hormone
- Fibroblast growth factor-23 (FGF-23)
The RDA for phosphorous is ____mg/day for adults
700 mg/day
Phosphorous needs are highest during which age range?
9yo - 18yo (puberty-adolescence)
_____________ is the major extracellular electrolyte and a primary regulator of extracellular fluid volume, membrane potential of cells, active transport across cell membranes, acid-base balance, body fluid osmolarity and acid-alkaline balance.
Sodium
Intake of what dietary component increases the urinary excretion of sodium and may cause a negative sodium balance?
caffeine
Food sources of sodium include:
processed foods, table salt, meats, high protein food, sardines, bacon, and
beans.
Excessive intakes of sodium by sodium sensitive individuals (approximately 15% of adults) may contribute to:
hypertension and the development of cardiovascular diseases
Sodium is distributed in the body…
Approximately 30% is on the surface of bone crystals and approximately 70% is in
the extracellular fluid (plasma, interstitial fluid and intracellular fluid (in nerve and muscle)).
How much of the bodies REE is dedicated to regulating sodium?
body devotes 20-40% of the resting energy expenditure to maintain function of sodium-potassium pumps throughout the body
Sodiums main functions include:
Maintenance of fluid balance
Nerve transmission
Muscle contraction
Maintenance of osmotic pressure
What percentage of sodium intake is actually absorbed?
95-100%, with ~05% excreted in the feces
By which 3 main mechanisms does
sodium absorption occur across the enterocyte brush border membrane?
Na+ /glucose transport system
Electroneutral Na+ and Cl- cotransport system
Electrogenic sodium absorption mechanism
The mechanism of the Na+ /glucose transport system for sodium absorption is:
The carrier is on the brush border and sodium and glucose bound to the carrier go to the inner surface of the brush border cell for release. Sodium is absorbed and pumped (by the Na+ /K+ ATPase pump) across the basolateral membrane. Glucose diffuses across.
The mechanism of the Electrogenic sodium absorption mechanism for sodium absorption is:
Sodium enters the luminal membrane via a sodium channel and exits, as with ‘I’ and ‘II’, via the Na+ /K+ ATPase pump.
1 tsp of salt contains how much sodium?
One teaspoon of salt (sodium chloride) contains 2.3g or 2300 mg of sodium.
Processed foods account for how much of total sodium consumption?
Processed foods account for ~75% of the total sodium consumed
How much sodium does the average American consume compared to the DV?
Americans consume 3000-5000 mg of sodium per day. The Daily Value (DV) for sodium used on food labels is 2400mg
The Adequate Intake (AI) of sodium is:
1500mg
The Tolerable Upper Limit (TUL) for sodium is:
2300 mg/d for adults (which is equivalent to 5.8g of sodium chloride/day)
The Adequate Intake (AI) of sodium for ages 0-3 years old is:
0.12-1.0g/day
Sodium can lead to loss of what other mineral?
Sodium (dietary) leads to increased urinary calcium excretion but also increases calcium absorption and decreases fecal calcium excretion. The net result is still some calcium loss.
Those competing in endurance events are at higher risk of a deficiency in what mineral?
sodium (hyponatremia)
Sodium deficiency is rare but can be caused by:
result from sweating (> 3% of total body weight), with prolonged vomiting or diarrhea, with use of certain diuretics and with some renal diseases.
Signs and symptoms of low sodium include:
Many signs and symptoms of low sodium are due to swelling of the brain and increased intracranial pressure causing: nausea vomiting headache mental confusion lethargy weakness hyperreflexia hyporeflexia delirium coma psychosis focal weakness ataxia
What gastrointestinal symptoms can low sodium cause?
abdominal cramps, temporary loss of sense of taste, decreased appetite, nausea, vomiting
Deficiency in this mineral can cause low blood pressure.
sodium
True or False. Sodium deficiency can cause musculoskeletal/neurological – muscle cramps, twitching and rigidity.
True
Sodium toxicity and overconsumption can lead to…
Hypernatremia
Signs and symptoms of hypernatremia include:
dizziness, fainting, low blood pressure, decreased urine production, muscle rigidity, tremor, spasticity, and hyperreflexia
The most accurate method for testing sodium is?
presence or absence of changes in blood pressure, the presence/absence of edema and 24 hr urinary excretion
**Serum sodium is not a measure of recent
intake
What correlation does hypertension have with sodium intake?
increased dietary sodium intake may lead to increased blood pressure. Note that
one’s sensitivity to the blood pressure elevating effects of salt increase with age
** The role of sodium in causing essential hypertension is unknown
True or False. Salt sensitivity is NOT thought to be related to genetic polymorphism(s) in the gene that codes for angiotensinogen.
False
What is the connection between sodium intake and cancer?
Increased salt intake may damage cells that line the stomach (increasing the risk of H.
pylori infection and damage to genes which can promote cancer
Can low sodium intake lead to osteoporosis?
Studies show that a low sodium diet (2 g/d) for 6 months can lead to significantly
decreased calcium excretion.
Can increased sodium intake cause kidney stones?
Because high salt in the diet can increase the excretion of calcium from the urine, it
can increase calcium stones.
What classes of drugs can lead hyponatremia?
Diuretics Nonsteroidal Antiinflammatory drugs Opiate derivatives Phenothiazines Selective serotonin reuptake inhibitors (SSRIs) Tricyclic antidepressants Anticonvulsants Antilipidemics Antineoplastics Hormones Oral hypoglycemics
What is the RDA for sodium for children ages 1-3 yo?
1.0 g/day
What is the RDA of sodium for ages 4-8?
1.2 g/day.
What is the RDA of sodium for ages 9-50?
1.5 g/day
What is the RDA of sodium for ages 51-71?
- 3 g/day for 51-70 yo
1. 2 g/day for 71 yo and older
Calcium is absorbed in the ________.
Duodenum mostly. A little in the jejunum and ileum.
When there is low serum calcium the body does what to restore levels?
The parathyroid releases parathyroid hormone (PTH) to stimulate tissues to convert vitamin D to calcitriol (active form, a.k.a. D3). Calcitriol - increases calcium absorption from intestine and regulates kidney excretion of calcium.
When there is high serum calcium the body does what to lower levels?
Parafollicular cells of thyroid gland release hormone calcitonin to “tone it down”. Prevents bone from releasing calcium by inhibiting osteoclasts, decreases GI absorption, and promotes kidney excretion.
Malabsorption of calcium in the elderly is likely due to ___________________.
vitamin D deficiency
Absorption of calcium _________ with age.
Decreases.
i.e. - post-menopausal women intake 800mg/day absorb 13-43%.
The tolerable upper limit for calcium is ____________.
2500mg/day
Food sources calcium include:
Dairy - Calcium fortified milk, plain yogurt, cheese.
Non-dairy - Egg yolk, soy milk with calcium added, sardines, tofu, turnip greens, salmon, okra, blackstrap molasses, beet greens, soybeans, perch, white beans, kale, clams, almonds, rainbow trout, oatmeal.
Fortification of grains can contribute minimally
Symptoms calcium deficiency
Irritability Pins & Needles (hands and feet) Hyperactive reflexes Muscle cramps Twitching Possible seizures (convulsions) Tetany Lethargy Muscle weakness Confusion
Other:
Rickets (usually vitamin D but can be lack of calcium and phosphorus)
Causes of calcium deficiency
Low serum phosphorus or magnesium, medications, vit D deficiency, hypoparathyroidism .
Often undiagnosed – bones continue to release calcium into blood for years. Over time can lead to osteoporosis with bone fractures and loss of height.
In children, calcium deficiency can lead to ________
Paresthesia of mouth/extremities, stunted growth, tetany, seizures.
Calcium toxicity can be cause by________(name 3 causes).
- Individuals with hyperactive parathyroid gland
- Excessive vitamin D intake
- Breast cancer, lung cancer (effects PTH)
Symptoms of hypercalcemia
Dehydration Lethargy Nausea/vomiting Anorexia Depression Death
Plant sources of calcium are _____ bioavailable than dairy.
Less.
Ie: absorption for spinach = 5%, dairy milk = 27%.
Oxalic acid, phytic acid, and other compounds from plants can combine with calcium, creating _________________.
indigestible salts that inhibit calcium bioavailability.
–(Plant sources from plants that do not have these compounds have similar absorption as dairy - such as broccoli, kale, & cabbage, though the amount of calcium is lower). Eating a variety of foods together can reduce this reaction.
Compounds/interactions that can reduce calcium absorption include____________________(name 3).
Caffeine (minimally), phosphorus, low vitamin D (greatest risk).
*Dietary fiber may inhibit absorption. Cellulose –study found 10g/day dose led to negative calcium balance. Study - Wheat bran reduced calcium (and phosphorus) in infants age 6-16 months given 5-10g wheat bran three times daily for constipation.
For fractures, consider calcium,_______and ________ together in combination versus calcium alone.
vitamin D and phosphate.
*Also - if supplementing, consider magnesium as well.
Calcium citrate versus calcium carbonate.
Carbonate – lower solubility in persons with low stomach acid (reduces absorption). Take at meal to increase absorption.
Citrate - Less dependent on stomach acid for absorption. Can be taken without food.
In general calcium is best taken with food regardless of stomach acid availability.
Other forms (less common) - sulfate, ascorbate, microcrystalline, hydroxyapatite.
The optimal dose of calcium for best absorption is _____mg.
500mg or less.
**Supplementation varies. Usually 200-300 in a multi-vitamin, or 500 isolated.
Hypocalcemia in serum is likely caused by ___________.
hypoparathyroidism, or another factor.
A genetic causes of hypocalcemia is____________.
Autosomal dominant hypocalcemia (ADH)– low levels calcium in blood, often alongside high phosphate and low magnesium. Sometimes low PTH.
Causes high levels calcium in urine – kidney stones.
Which form of calcium supplementation is best for the elderly and individuals with hypochlorhydria?
a. calcium carbonate
b. calcium lactate
c. calcium citrate
d. calcium gluconate
Calcium citrate has shown to absorb without the need for HCl (which can be depleted in older individuals)
The bioavailability of magnesium may be most reduced by?
a. concurrent ingestion of zinc
b. concurrent ingestion of calcium
c. dietary fats
d. dietary fiber
Zinc - may interfere with Mg absorption / utilization
Which mineral is found in every cell in the body?
a. magnesium
b. sodium
c. calcium
d. phosphorus
d. Phosphorus (phospholipid bilayer)
