This document provides an overview of calcium, including its distribution in the body, sources, functions, dietary requirements, absorption and excretion. Key points discussed include: - Calcium is mainly found in bones, with 99% located in the skeleton. Its main functions are structural support and muscle/nerve signal transmission. - Dietary calcium recommendations vary by age but adults generally need 1000-1500mg per day. Major sources include dairy products. - Calcium absorption occurs primarily in the small intestine and is regulated by parathyroid hormone, calcitonin, and vitamin D. Around 30-40% of dietary calcium is typically absorbed. - Homeostatic control of calcium levels involves a balance between intestinal absorption

1. Presented by: Dr. Neetu Singh
2nd yr pg

2. Contents
I. Introduction
II. Calcium and phosphorus Distribution
III. Source
IV. Function
V. Dietary requirements
VI. Absorption
VII.Excretion
VIII.Factors affecting absorption
IX. Factors affecting calcium metabolism
X. Diet
XI. Parathormone
XII.Calcitonin
XIII.Clinical consideration
XIV.Summary
XV.references

3. Calcium facts
• Soft grey alkaline earth metal
• Symbol Ca
• Number 20
• Group II
• Divalent cation
• Atomic weight 40 g/mol
• Single oxidation state +2
• Fifth most abundant element in Earth´s crust
• Essential for living organisms
Harrison et al., "Ionic and Metallic Clusters of the Alkali Metals in Zeolite Y", J. Solid State Chem.,
54, 330-341 (1984).

4. Calcium history
• Latin calx or calcis meaning ”lime”
• Known as early as first century when ancient Romans prepared lime
as calcium oxide
• Isolated in 1808 by Englishman Sir Humphrey Davy through the
electrolysis of a mixture of lime (CaO) and mercuric oxide (HgO
• In 1883 demonstrated Sydney Ringer the biological significance of
calcium

5. Calcium occurrence
In nature
• Does not exist freely
• Occurs mostly in soil systems as limestone (CaCO3),
gypsum (CaSO4*2H2O) & fluorite (CaF2)
In the body
• The most abundant mineral
• Average adult body contains app. 1 kg
• 0.1 % in the extra cellular fluid
• 1 % in the cells
• The rest (app. 99 %) in the skeleton
(Bones can serve as large reservoirs, releasing
calcium when extracellular fluid concentration decreases
and storing excess calcium)
Calcium Orthophosphates: Occurrence, Properties and Major Applications
*

6. Distribution of calcium
• Skeleton - 99%
• Muscle – 0.3%
• Other tissues – 0.7%
• 800mg of calcium is absorbed
/day

7. Source of calcium

8. Recommended calcium intake
Age Amount of calcium
Infants
Birth to six months 400mg
6 months to 1 year 600mg
Children / young adults
1 – 10 years 800 – 1200mg
11 – 24 years 1200 – 1500mg
FAO/WHO Expert Group. 1962. Calcium Requirements. Rome, FAO.

9. Recommended calcium intake
Adult women
Pregnant and lactating 1200 – 1500mg
25 - 49 yrs(premenopausal) 1000mg
50 – 64 yrs (post menopausal
taking estrogen ) 1000mg
50 – 64 yrs(post menopausal
not taking estrogen ) 1500mg
Over 65 yrs old 1500mg

10. Recommended calcium intake
Adult men
25 – 64 yrs old 1000mg
Over 65 yrs old 1500mg

11. FUNCTIONS OF CALCIUM
 Muscle contraction
Formation of bone and teeth
 Coagulation of blood
Nerve transmission: Integrity of cell
membrane by maintaining the resting
membrane potential of the cells
Release of certain hormones
The Role of Calcium in Coagulation and Anticoagulation M. E. Mikaelsson Volume 26, 1991, pp
29-37

13. Calcium functions
• Major structural element in the vertebrate
skeleton (bones and teeth) in the form of calcium
phosphate (Ca10(PO4)6(OH)2 known as
hydroxyapatatite
• Key component in the maintenance of the cell
structure
• Membrane rigidity, permeability and viscosity are
partly dependent on local calcium concentrations

14. Calcium functions (Bone)
• Osteoclasts (bone cells)
remodel the bone by
dissolving or resorbing
bone
• Osteoblasts (bone
forming cells) synthesize
new bone to replace the
resorbed bone
- Found on the outer
surfaces of the bones
and in the bone cavities

15. Interactions
• Phosphate: ↓ calcium excretion in the urine
• Caffeine: ↑ urinary and fecal excretion of calcium
• Sodium: ↑ sodium intake, ↑ loss of calcium in urine
• Dietary constituents: Phytic acid can reduce
absorption of calcium by forming an insoluble salt
(calcium phytate)
• Iron: calcium might have inhibitory effect on iron
absorption

16. Three in Calcium
3 Sites – Intestines, bones, blood.
3 hormones – Parthormone, Calcitonin, Vitamin D.
3 chemical forms – protein bound, ionic calcium, crystalline form.
3 crystalline forms – Hydroxyapatite(ha), calcium pyrophosphate
dihydrate(CPPD), Calcium oxalate.
3 forms of pathological calcification –dystrophic calcification,
metastatic calcification, calcium stone
(lithiasis)

17. Absorption and excretion
• Usual intakes is 1000 mg/day
• About 35 % is absorbed (350 mg/day) by
the intestines
• Calcium remaining in the intestine is
excreted in the feces
• 250 mg/day enters intestine via secreted
gastrointestinal juices and sloughed
mucosal cells
• 90 % (900 mg/day) of the daily intake is
excreted in the feces
• 10 % (100 mg/day) of the ingested
calcium is excreted in the urine
• Calcium must be in a soluble and ionized
form before it can be absorbed

18. Absorption and excretion
factors
• Absorption increased by:
- Body need
- Vitamin D
- Protein
- Lactose
- Acid medium
• Absorption decreased by:
- Vitamin D deficiency
- Calcium-phosphorus imbalance
- Oxalic acid
- Phosphorous
- Dietary fiber
- Excessive fat
- High alkalinity
- Also stresses and lack of exercise
• Excretion increased by:
- Low parathyroid hormone (PTH)
- High extracellular fluid volume
- High blood pressure
- Low plasma phosphate
- Metabolic alkalosis
• Excretion decreased by:
- High parathyroid hormone
- Low extracellular fluid volume
- Low blood pressure
- High plasma phosphate
- Metabolic acidosis
- Vitamin D3

19. Regulation
Vitamin D,
parathyroid hormone
and calcitonin

21. • Vitamin D (in active form)
- Has several effects on the intestine and
kidneys that increase absorption of
calcium and phosphate into the
extracellular fluid
- Important effects on bone deposition and
bone absorption

22. Regulation
Activation of vitamin D3
- Cholecalciferol formed in the skin
by sun
- Converted in liver
(feedback effect)
- 1,25 DHCC formation in kidney
- Controlled by PTH
- Plasma calcium concentration
inversely regulates 1,25 DHCC

23. Parathyroid hormone (PTH)
-Provides powerful mechanism for controlling extracellular
calcium and phosphate concentrations by regulating intestinal
reabsorption, renal excretion and exchange between the
extracellular fluid and bone of the two ions
Calcitonin (a peptide hormone secreted by the thyroid
gland)
-Tends to decrease plasma calcium concentration
-In general, has effects opposite to those of PTH
(quantitative role is far less than that of PTH in
regulating Ca ion concentration)

24. Regulation
• Compensatory responses to decreased plasma ionized calcium
concentration mediated by PTH & vitamin D
• PTH regulates through 3 main effects:
- By stimulating bone resorption
- By stimulating activation of vitamin D → ↑ intestinal Ca reabsorption
- By directly increasing renal tubular calcium reabsorption

25. Factors regulating plasma
calcium level
Calcitriol: 1, 25 DHCC
Increases intestinal absorption.
Stimulates calcium uptake by bone and
promotes calcification

26. Parathyroid Hormone:
•Action on bone
•Action on kidney
•Action on intestine

27. Plasma Ca
9-11mg/dl
Intestinal
Ca
Bone Ca Renal Ca
Calcitriol
calcitonin
PTH PTH
calcitriol Vit D
PTH

28. Phosphate

29. Phosphate
85% is present in bone(500 – 600gm)
Present in the form of hydroxyapatite and in
some areas as amorphous calcium phosphate.

30. Distribution of phosphorus
2.5 to 4.3mg/100ml is present in adults
5 to 6 mg/100ml is present in children

32. Source of phosphorus
Present in all foods
Milk
Meat
Fish
cereals
Pulses and nuts

33. Daily requirement
Adults – 900 mg
Infants – 240mg
Pregnant and lactating women – 1200mg

34. Functions of phosphorus
Development of bone and teeth
Formation of high energy compounds
Required for formation of phospholipids, phospho-
proteins and DNA and RNA
Several enzymes and proteins are activated by
phosphorylation.

35. Clinical considerations

36. Deficiency
• A negative calcium balance occurs when net calcium
absorption is unable to replace losses
• The most dramatic symptoms are manifested in the teeth
and bones of young humans and animals → stunted growth,
poor quality of bones and teeth and malformation of bones

38. Measuring calcium
• Atomic absorption spectrometry (AAS) can
measure total amount of Ca2+ in tissue
• Fluorescent dyes can be used to measure Ca2+ in
vivo
• Calcium sensor (GFP-based) fluorescent protein
“cameleon” is non invasive and can be targeted to
various cellular compartments – enabling a study of
spatial and organellar aspects of calcium
homeostasis
• Neutron activation analysis enables total body
calcium to be measured in living persons
• Bone mineral content (BMC) and bone mineral
density (BMD) are used as indicators of calcium
insufficiency and as predictors of increased risk of
fracture, when compared to a reference range,
adjusted for age and gender

39. • Blood and urine calcium measurements
cannot tell how much calcium is in the bones.
A test similar to an X-ray, called a bone density
or "Dexa" scan, is used for this purpose.

40. Who Needs a Calcium Blood Test?
A calcium blood test can be part of a screen for a variety of diseases and conditions,
including osteoporosis, cancer, and kidney diseases.
This blood test may also be required to monitor ongoing treatments of other
conditionsedications you are taking don’t have any unintended side effects.
Your doctor may order this test if he or she suspects
any of the following conditions:
bone diseases, such as osteoporosis or osteopenia
cancer
chronic kidney or liver disease
disorders of the parathyroid gland
malabsorption or a disorder that affects how your body absorbs nutrients
an over or underactive thyroid gland

41. Toxicology
• The UL for calcium is 2500 mg/day
• MAS (Milk alkali syndrome)
- Rare and potentially life threatening
condition in individuals consuming large
quantities of calcium and alkali
- Characterized by renal impairment,
alkalosis and hypercalcemia: cause
progressive depression of the nervous
system
The role of cell calcium in current approaches to toxicology.
J G Pounds

42. high total calcium (hypercalcemia)
• Two of the more common causes of hypercalcemia are:
• Hyperparathyroidism, an increase in parathyroid gland function:
• this condition is usually caused by a benign tumor of the parathyroid
gland.
• Cancer: cancer can cause hypercalcemia when it spreads to the bones
and causes the release of calcium from the bone into the blood or when
a cancer produces a hormone similar to PTH, resulting in increased
calcium levels.
• Some other causes of hypercalcemia include:
• Hyperthyroidism
• Sarcoidosis
• Tuberculosis
• Prolonged immobilization
• Excess vitamin D intake
• Thiazide diuretics
• Kidney transplant
• HIV/AIDS

43. Low total calcium (hypocalcemia)
• The most common cause of low total calcium is:
• Low blood protein levels, especially a low level of albumin, which
can result from liver disease or malnutrition, both of which may
result from alcoholism or other illnesses. Low albumin is also very
common in people who are acutely ill. With low albumin, only the
bound calcium is low. Ionized calcium remains normal, and calcium
metabolism is being regulated appropriately.
• Some other causes of hypocalcemia include:
• Underactive parathyroid gland (hypoparathyroidism)
• Inherited resistance to the effects of parathyroid hormone
• Extreme deficiency in dietary calcium
• Decreased levels of vitamin D
• Magnesium deficiency
• Increased levels of phosphorus
• Acute inflammation of the pancreas (pancreatitis)
• Renal failure

44. Causes of Vitamin D deficiency
•Dietary insufficiency
•Poor exposure to sunlight
•Malabsorption
•Liver/ kidney disease (synthesis)
•Resistance to hormone receptor (rickets)

45.  Ricket refers to disorder in
vitamin – D
(calcium –phosphorous ratio)
 Resultant hypo-mineralization
 Three types: Infantile ,Adult
and familial
rickets
Longo, Dan L. et al. (2012). Harrison's principles of internal medicine. (18th ed. ed.). New York:
McGraw-Hill. ISBN 978-0-07174889-6.

46. Femoral and tibial bowing
Growth retardation
weakness
tetany
Susceptibility to fracture
Irritability
Clinical features of rickets
Longo, Dan L. et al. (2012). Harrison's principles of internal medicine. (18th ed. ed.). New York:
McGraw-Hill. ISBN 978-0-07174889-6.

47. Oral manifestation
Mellanby:
•Developmental abnormalities of
dentin and enamel
•Delayed eruption
•Misalignment of teeth in the jaw
•High caries index
•Enamel hypoplasia

48. Osteomalacia
Clinical features
Bone pain and
tenderness
Peculiar waddling or
“penguin”gait
Tetany
Greenstick bone
fractures
Myopathy

49. Severe Periodontitis
Thin or absent trabeculae
Loosened teeth
Weakened jaw bones
Oral manifestation

50. Hypervitaminosis D
CLINICAL FEATURES
Gastrointestinal
disturbances
Nausea
Vomiting
Loss of appetite
Thirst
Polyuria
Fatigability

51. Radiological features
•Metastatic deposits of
calcium almost
anywhere in the body
most commonly around
joints

52. Management
Cortisone – increases urinary excretion of calcium

53. Hypocalcemia
Condition where there is decreased calcium
level in serum of blood
Classification based on the mechanism
1. Chronic hypocalcemia
causes
chronic renal failure
Hereditory and acquired
hypothyroidism
Vitamin D deficiency

54. 2. Transient hypocalcemia
Causes
Severe sepsis
Burns
Acute renal failure
Extensive transfusions with
citrated blood .
3. acute hypocalcemia
Certain medications like protamine,
heparin

55. Causes of hypocalcaemia
Low parathyroid hormone levels
(hypoparathyroidism)
Parathyroid agenesis
Parathyroid destruction
Surgery
Radiation
Infiltration by metastasis or systemic disease
Autoimmune

56. Clinical features
•Muscle spasms, carpopedal spasms,
•Facial grimacing (a expression of pain)
•Bronchospasm, laryngospasm,
•Convulsions
•Respiratory arrest
•Increased intracranial pressure
•Irritability, depression, psychosis
•Intestinal cramps
•Chronic malabsorption
•Arrhythmias
•Seizures of all types

58. Management of hypocalcaemia
Calcium gluconate 10ml 10%IV diluted in 50ml
of 5% dextrose 0.9% Nacl by slow injection
Vitamin D - if hypocalcaemia persist

59. Hypoparathyroidism
Definition
Disorder of mineral metabolism caused by insufficient
activity of parathyroid glands
Types
Heriditary
pseudoAquired

60. Clinical features
Paresthesia
Muscle cramps
Seizures
Tetany
Chovestek’s sign
Trousseau’s sign
Accouchers hand

61. Oral manifestation
Enamel hypoplasia
Malformed teeth
Anodontia
Short blunt root apices
Elongated pulp chambers
Multiple impacted teeth
Mandibular exostosis

62. •Short (less than 5 feet tall) built and round
face.
•Shortening of metacarpal joints and
presence of dimples in the joint.
•Mental retardation
Clinical features

63. •Enamel hypoplasia
•External root resorption
•Delayed eruption
•Root dilaceration
Radiographic features
Ash, Major M., Jr. and Nelson, S.J (2003). Dental anatomy, physiology, and occlusion (8th ed.).
Philadelphia: W.B. Saunders. ISBN 0-7216-9382-2.

64. Human health studies
• Resent studies showed
- Calcium may play a substantial contributing role in reducing the
incidence of obesity and prevalence of the insulin resistance
syndrome
- High calcium intake is associated with a plasma lipoprotein-lipid
profile predictive of a lower risk of coronary heart disease
compared with a low calcium intake
- Dairy product intake (with recommended calcium levels) protect
women consuming oral contraceptives from spine and hip bone
loss
- Children who avoid drinking cow milk have low dietary calcium
intakes and poor bone health

65. Conclusion
• Calcium is essential!!!
• A important mineral for human health
• Must meet adequate daily intake in
order to maintain a healthy skeleton
• A very exciting area for research

66. Shafers.Textbook of oral pathology.Ed 6th
Guyton and Hall. Textbook of medical physiology.Ed11th
Telfer, S.V. 1926. Studies in calcium and phosphorus metabolism. Q. J. Med., 20:1-
6.
Heaney, R.P. 1993. Protein intake and the calcium economy. J. Am. Diet. Assoc., 93:
1259-1260.
REFERENCES

67. Thank
you