Calcium and Magnesium

8/6/2019 Calcium and Magnesium

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CALCIUM AND MAGNESIUM

Done by: Melissa Adams

Sharmela Brijmohan


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CALCIUM

Atomic number:20

Atomic mass: 40.078

It is the most abundant mineral in the body.


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Benefits of adequate calcium throughout

life may include:

Prevention of osteoporosis

Lowered blood pressure

A lower incidence of colon cancer

Weight maintenance


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Benefits of adequate calcium throughout life

Bones and teeth contain 99 percent of all calcium inthe body. The other 1 percent is distributed within cellsand in body fluids, such as the blood. This smallpercentage is extremely important in maintaining body

functions, including:

Clotting of blood after injury

Nerve conduction

Muscle contraction Enzyme regulation

Control of blood pressure


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SOURCES OF CALCIUM

HIGH CALCIUM

SOURCES

GOOD CALCIUM

SOURCES

OTHER CALCIUM

CONTAINING FOODS

Contain 200 mg or

more of calcium per

serving and include

foods such as

milk, yogurt, hardcheeses, canned

salmon and sardines

with the bones, and

blackstrap molasses.

Contain 100-190 mg

calcium per serving

and include foods

such as

ice cream, custard,tofu, spinach, and

turnip greens.

Contain less than 100

mg calcium per servingand include foods such

as

cottage cheese,

almonds, dried beans,

eggs, mustard greens,broccoli, carrots,

oranges, orange juice,

figs, dates, raisins, corn

tortillas, pancakes, and

molasses.

Some of the foods in theother group can be

significant contributors

to total calcium intake

when eaten frequently

as some foods arefortified with calcium


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Recommended Daily value of Calcium

AGE MALE FEMALE PREGNANT LACTATING

Birth to 6 months 210 mg 210 mg

7-12 months 270 mg 270 mg

1-3 years 500 mg 500 mg

4-8 years 800 mg 800 mg

9-13 years 1,300 mg 1,300 mg

14-18 years 1,300 mg 1,300 mg

19-50 years 1,000 mg 1,000 mg 1,300 mg 1,300 mg

50+ years 1,200 mg 1,200 mg 1,000 mg 1,000 mg


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METABOLISM OF CALCIUM( CALCIUM

HOMEOSTASIS)

Calcium Homeostasis is an important mechanism

adapted by body cells to keep normal levels in order

for metabolic and physiologic functions to be carried

out. The mechanism utilizes hormones, blood, and

receptor cells. Regulation is important to prevent

Hypercalcaemia (high calcium levels) and

Hypocalcaemia (low calcium levels)


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HOMEOSTASIS)

FUNCTION OF CALCITONIN

Calcitonin is a hormone that controls the calcium concentration in thebody by maintaining a proper calcium level in the bloodstream and issecreted from the parafollicular cells of the Thyroid gland.

Calcitonin decreases the reabsorption of calcium and phosphate from thebones to the blood thereby lowering blood levels of these minerals. Thisfunction of calcitonin helps maintain normal blood levels of these mineralswhile helping to maintain a strong bone matrix.

Hypercalcaemia triggers the stimulation of calcitonin and means that nomore calcium will be removed from the bones until there is a real need formore calcium in the blood. The ability to decrease blood calcium levels atleast in part by effects on two well-studied target organs:


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HOMEOSTASIS)

FUNCTION OF CALCITONIN

Bone: Calcitonin suppresses resorption of bone by

inhibiting the activity of osteoclasts, (a cell type that"digests" bone matrix, releasing calcium and phosphorusinto blood.)

Kidney: Calcium and phosphorus are prevented frombeing lost in urine by reabsorption in the kidney tubules.Calcitonin inhibits tubular reabsorption of these twoions, leading to increased rates of their loss in urine


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HOMEOSTASIS)

FUNCTION OF PARATHORMONE

Parathyroid Hormone is secreted from the

Parathyroid glands located behind the Thyroid gland

and its effects are antagonistic to Calcitonin.

It is secreted in response to low blood calcium levels

and it' affect is to increase those levels.

In conjunction with increasing calcium concentration,the concentration of phosphate ion in blood is

reduced


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HOMEOSTASIS)


Parathyroid hormone accomplishes its job by stimulating at least threeprocesses:

Mobilization of calcium from bone: PTH increases the stimulation of the number andthe size of specialized bone cells called osteoclasts. Bone calcium is bonded tophosphorus in a compound that is called calcium phosphate. So when calcium isreleased into the bloodstream, phosphorus is released along with it...

Enhancing absorption of calcium from the small intestine: Facilitating calciumabsorption from the small intestine would clearly serve to elevate blood levels ofcalcium.PTH stimulates this process, but indirectlyby stimulatingproduction of the

active form of vitamin D in the kidney. Vitamin D induces synthesis of a calcium-bindingprotein in intestinal epithelial cells that facilitates efficient absorption of calcium intoblood.

Suppression of calcium loss in urine: In addition to stimulating fluxes of calcium into bloodfrom bone and intestine, PTH puts a brake on excretion of calcium in urine, thusconserving calcium in blood. This effect is mediated by stimulating tubular reabsorption ofcalcium. Another effect ofPTH on the kidney is to stimulate loss of phosphate ions in urine


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HOMEOSTASIS)


Hypoparathyroidism or insufficient secretion ofPTH leads toincreased nerve excitability. The low blood calcium levels trigger

spontaneous and continuous nerve impulses, which trigger musclecontraction.

Hyperparathyroidism or and excessive secretion ofPTH leads to anincrease in the osteoclast activity that removes calcium from thebones and excretes it into the bloodstream. This increase in

calcium in the blood may lead to kidney stones or a buildup ofmineral deposits that can be found in abnormal places. It may alsolead to a bone disease called osteitis fibrosa cystica where the bonemass decreases, decalcification occurs, cyst like cavities appear inthe bone and spontaneous fractures result.


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CLINICALAPPLICATIONS:

Vitamin D deficiency causes a net demineralization of bone resulting in:

Rickets in children: continued formation of collagen matrix of bone, incomplete

mineralization, resulting in soft pliable bones

Osteomalacia in adults: demineralization of pre-existing bone increases susceptibility

to fractures

Chronic Kidney Failure Leads to damage of the enzyme to convert inactive Vitamin D to

Active form in order for calcium to be absorbed.

CLINICALAPPLICATIONS:

Vitamin D deficiency causes a net demineralization of bone resulting in:

Rickets in children: continued formation of collagen matrix of bone,

incomplete mineralization, resulting in soft pliable bones

Osteomalacia in adults: demineralization of pre-existing bone increases

susceptibility to fracturesChronic Kidney Failure Leads to damage of the enzyme to convert inactive

25- Hydroxycholecalciferol

25- OH-D3Main storage form ofVitamin D

plants ergocalciferol catalyzed by the liver

animals cholecalciferol by a specific hydroxylase

1, 25- Dihydroxycholecalciferol

1, 25- diOH-D3

25-hydroxycholecalciferol

1-hydroxylase

utilizing Cytochrome P450, NADPH, molecular

oxygen

Stimulated Inhibited

PTH, PHOSPHORUS 1- 25, diOH D3


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MAGNESIUM

Atomic number: 12

Atomic mass: 24.3050

Magnesium is a critical co-factor in more than 300 enzymatic

reactions in the human body. Potassium and magnesium are the most abundant cations

found within the cells of the body with magnesium being the

most abundant divalent cation

If a diet is high in phosphorus (common in many meat dishesas lunch meats, hot dogs, etc. and also in soda drinks), the

phosphate binds up the magnesium into magnesium

phosphate, which isn't absorbed. Thus you need more

magnesium for complete balance


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MAGNESIUM

In disease and stress states, more magnesium is needed. If a person is usingdiuretics (water pills), he should make sure his magnesium intake is adequate.Potassium supplementation is usually needed also. The higher the protein youconsume, the more magnesium is needed. When large amounts of calcium areconsumed, you need more magnesium.

Normal development apparently depends on the presence of magnesium.Approximately 70 percent of the magnesium in the body is found in theskeletal system. At least half of the magnesium in the body is combined withcalcium and phosphorus in the bones. The remainder is in the muscles, redblood cells and the other tissues of the body.

Magnesium ensures the strength and firmness of the bones, and it makes theteeth harder. Adequate intake of magnesium counteracts acidity, poorcirculation and glandular disorders. Children with magnesium deficiency arevery often mentally backward.


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FUNCTIONS OF MAGNESIUM

Needed for the proper functioning of muscles and

nerves (inhibitory to muscle contraction).

Activates cellular enzymatic activity.

Important for calcium, vitamin C, phosphorus,

sodium and potassium metabolism.

Important for converting blood sugar into energy.

Anti-stress


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BENEFITS OF MAGNESIUM

Magnesium also is vital for maintaining a healthy heart.

Magnesium helps stabilize the rhythm of the heart and helpsprevent abnormal blood clotting in the heart.

Magnesium also aids in maintaining healthy blood pressurelevels.

Magnesium is useful in preventing unwanted calcification in thekidney, bladder and in the joints.

The mineral magnesium can significantly lower the chance ofheart attacks and strokes, and can even aid in the recovery froma heart attack or stroke.

Magnesium also helps maintain proper muscle function. Itworks to keep muscles properly relaxed. Because of its benefitsin relieving stiff muscles, magnesium can be especially beneficialto fibromyalgia patients.


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SOURCES OF MAGNESIUM

FOOD MILLIGRAMS (mg) % DV

Halibut, cooked, 3 ounces 90 20

Almonds, dry roasted, 1 ounce 80 20

Cashews, dry roasted, 1 ounce75 20

Soybeans, mature, cooked, cup 75 20

Spinach, frozen, cooked, cup 75 20

Nuts, mixed, dry roasted, 1 ounce 65 15

Cereal, shredded wheat, 2

rectangular biscuits

55 15

Oatmeal, instant, fortified, prepared

w/ water, 1 cup

55 15

Potato, baked w/ skin, 1 medium 50 15

Peanuts, dry roasted, 1 ounce 50 15


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SOURCES OF MAGNESIUM

FOOD MILLIGRAMS( mg) % DV

Wheat Bran, crude, 2Tablespoons 45 10

Black-eyedPeas, cooked, cup 45 10

Yogurt, plain, skim milk, 8 fluid ounces 45 10

Bran Flakes, cup40 10

Vegetarian Baked Beans, cup 40 10

Rice, brown, long-grained, cooked,

cup

40 10

Lentils, mature seeds, cooked, cup 35 8

Avocado, California, cup pureed 35 8

Kidney Beans, canned, cup 35 8

Pinto Beans, cooked, cup 35 8

Wheat Germ, crude, 2Tablespoons 35 8

Chocolate milk, 1 cup 33 8

Banana, raw, 1 medium 30 8


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RECOMMENDED DAILY ALLOWANCE OF MAGNESIUM

LIFE STAGE AGE MALES mg/day FEMALES mg/day

Infants 0 6 months 30 ( AI) 30 (AI)

Infants 7 12 months 75 ( AI) 75(AI)

Children 1 3 years 80 80



Adolescents 14 18 years 410 360

Adults 19 30 years 400 310

Adults 31 years & older 420 320

Pregnancy 18 years & younger - 400

Pregnancy 19 30 years - 350

Pregnancy 31 years & older - 360

Breast Feeding 18 years & younger - 360

Breast Feeding 19 30 years - 310

Breast Feeding 31 years & older - 320


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METABOLISM OF MAGNESIUM( MAGNESIUM

HOMEOSTASIS)

Four types of glands are involved in magnesium homeostasis:medullary-adrenal, parathyroid, medullary-thyroid and the betacells of the islets of Langerhans

It is interesting to note that the three types of glands thatcontrol calcium and potassium metabolism (medullary-thyroid.parathyroid and the beta pancreas) exercise in parallel fashionadded regulatory effects on magnesium metabolism

The absorption of magnesium from the intestines may be

influenced by the parathyroid hormone,

the condition of the intestines

the rate of water absorption, and the amounts of calcium, phosphateand lactose (milk sugar) in the body


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HOMEOSTASIS)

There are about 19 g of Mg in the average 70 kg adult body, ofwhich approximately 65%is found in bone and teeth, and the rest is distributed betweenthe blood, body fluids, organs and other tissue

Over half of the bodys magnesium is stored in the bone, about1% is found in extracellular fluid (20-30% bound to protein; therest free) and the rest is in soft tissues, particularly muscle. Thekidney controls the homeostasis of magnesium.

Extracellular magnesium in serum is 33% protein bound, 12%complexed to anions, and 55% in the free ionized form. At thecellular level, magnesium appears to influence the properties ofvarious cell membranes; this process is thought to occur bymeans of calcium channels and ion transport mechanisms.


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HOMEOSTASIS)

Calcium flux is inhibited by magnesium from sarcolemmal membranes,through competition for binding sites on actin and via changes in theadenylate cyclase-cyclic AMP system. The next known physiologic roleof magnesium involving cell membranes pertains specifically to itsinterrelationship with the sodium-potassium-ATPase pump.

At the cellular level, magnesium also serves as a cofactor for manyintracellular enzymes that generate energy via hydrolysis of ATP. It isalso involved in DNA transcription and protein synthesis. Magnesium isresponsible for the maintenance of transmembrane gradients ofsodium and potassium.

ATP (adenosine triphosphate), the main source of energy in cells, mustbe bound to a magnesium ion in order to be biologically active.


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HOMEOSTASIS)

Magnesium plays a role in the stability of all

polyphosphate compounds in the cells, including those

associated with DNA and RNA synthesis.

Magnesium depletion depresses both cellular and

extracellular potassium and exacerbates the effects of low-

potassium diets on cellular potassium content. Muscle

potassium becomes depleted as magnesium deficiency

develops, and tissue repletion of potassium is virtuallyimpossible unless magnesium status is restored to normal.


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HOMEOSTASIS)

Calcium and magnesium belong to a group of"parasympathetic" elements (which includes chromiumand copper), that exhibit anti-inflammatory ordegenerative properties at higher amounts, in contrast to

elements such as potassium or iron, which are pro-inflammatory when high:

Adequate Vitamin D levels will assist intestinalabsorption of calcium, magnesium and phosphorus

INFLAMMATORY

LOW AMOUNTS

DEGENERATIVE

HIGH AMOUNTS

Ca, Cu, Mg, Cr


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METABOLISM OF MAGNESIUM(MAGNESIUM

HOMEOSTASIS)

UNDERSTANDING NEUROENDOCRINE FEEDBACK

Magnesium deficit (MD) falling short of the amount) directly causes areduced production of cAMP in the cell, probably by inhibition of Mg-dependent adenylate cyclase. (cAMP acts as a second messenger system

under the stimulation of the autonomic nervous sytem)

The organism responds by stimulation of the presynaptic sympatheticfibers (and of the medullary-adrenal glands which producecatecholamines (especially noradrenalin) which in turn stimulate thecAMP-responsive beta receptors.

Magnesium overload (MO), like an excess of catecholamines, directly causesan increased production of cAMP in the cell, probably by stimulation of adenylatecyclase


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UNDERSTANDING THE NEUROENDOCRINE FEEDBACK

The organism reacts by slowing the response of the

sympathetic fibers and of the medullary-adrenal glands

which inhibits production of catecholamines and

therefore of cAMP.

Excess secretion of adrenaline/ noradrenalin

(epinephrine/norepinephrine) ultimately stimulates

adrenergic receptors (1 &2, 1&2) which then

activates enzymes such as adenylate cyclase orphospholipase C.


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BIBLIOGRAPHY

PAMELA C. CHAMPE, RICHARD A.HENRY& DENISE R. FERRIER, Lippincotts Illustrated

Reviews, Biochemistry 4th Edition, 2008, R.R Donnelley & Sons, Philadelphia USA

LINDA S. COSTANZO, PHYSIOLOGY 3RD EDITION, 2006, Saunders-Elsevier, PhiladelphiaUSA

Dietary Supplement Fact Sheet: Calcium

(2009/08/11)

Calcium (2009/07/09) (2009/08/11) Endocrine System 1 for Medical Assistants

(2009/08/10)

Calcitonin(2009/08/10)

ParathyroidHormone

(2009/08/10)

MICHAEL B. SCHACHTER 1996

(2009/08/10)

On the importance ofMagnesium,DR.H.RAY EVERS, 2008/05/20,

(2009/08/10)


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BIBLIOGRAPHY

Benefits ofMagnesium, ELIZABETH WALLING, (2009/08/10)

Function ofMagnesium in the body

(2009/08/10)

Food sources ofMagnesium< http://www.hoptechno.com/bookfoodsourcemg.htm> (2009/08/10)

Magnesium, (2009/08/10)

Magnesium Recommended Daily Allowance (RDA), 2008/04/10 (2009/08/10)

Magnesium metabolism, 2005/04/09, (2009/08/10)

(2009/08/10)

Magnesium in Biology (2009/08/11)

Magnesium (2009/08/11)

Magnesium (2009/08/11)

Magnesium Online Library (2009/08/11)

Hypermagnesaemia 2007/10/11< http://emedicine.medscape.com/article/766604-

overview>(2009/08/11)

Calcium and Magnesium

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