1. CALCIUM METABOLISM
Presented by : Dr. Rohan Shrivastava
MDS

2. CONTENTS
Overview about calcium
Effects of minerals on calcium
Dietary sources of calcium
Daily requirement of calcium
Function & Storage
Distribution of calcium
Absorption of calcium
Regulation of calcium
Disorders of calcium metabolism

3. OVERVIEW ABOUT CALCIUM
 About 99% of calcium in our body is found in BONES.
 The concentration of calcium in plasma is higher than the interstitial fluid.
 Intracellular concentration of calcium is considerably less that is 1%.
 Most abundant mineral in the human body.
 Total calcium in the human body is about 1 to 1.5 kg.

4. EFFECTS OF MINERALS ON CALCIUM
 Phosphate : decreases the calcium excretion in the urine.
 Caffeine : increases the calcium excretion in urine and feces.
 Sodium : increased sodium intake also increases calcium in urine.
 Iron : calcium might have inhibitory effect on iron absorption.

5. DIETARY SOURCES OF CALCIUM
 Milk is a good source of calcium.
 Egg, fish, cheese, beans, lentils, nuts, cabbage and vegetables.

6. DIETARY SOURCES
 Whole milk = 10%
 Low fat milk = 18%
 Cheese = 27%
 Other dairy products = 17%
 Vegetables = 7%
 Other substances such as meat, egg, grains, sugar, coffee, tea, chocolate, etc. = 21%

7. DAILY REQUIREMENT OF CALCIUM
 Adults = 500mg/day
 Children = 1200mg/day
 Pregnant/lactation =1300mg/day
 NOTE- After the age of 50, tendency for osteoporosis is increased so that it is
prevented by increased calcium (1500mg/day) & vitamin D (20ɥg/day)

9. FUNCTION OF CALCIUM
Calcium is very essential for many activities
in the body such as:
 Muscle activity
 Nerve conduction
 Myocardium
 Coagulation
 Bone & teeth
 Hormone secretion

10. STORAGE OF CALCIUM
 Primary site for storage of calcium is bones(about 1000 gms)
 Some calcium is stored within cells(endoplasmic reticulum and mitochondria)
 Bone is produced by osteoblast cells which produce collagen, which is then
metabolized by calcium and phosphate into the blood stream.
 There is constant exchange of calcium between blood and bone.

11. • calcium in plasma is of 3 types – FREE or BOUND or
UNBOUND calcium.
• In blood, 50% of calcium is free & is metabolically active.
• It is required for the maintenance of nerve function,
membrane permeability, muscle contraction and hormone
secretion.
• Bound calcium : 41% of plasma calcium is bound to
protein mostly albumin.
• Complexed calcium : 9% of plasma calcium is complexed
with anions including bicarbonate, phosphate, lactate and
citrate.

12. FACTORS AFFECTING ABSORPTION

13. MECHANISM OF ABSORPTION OF
CALCIUM
 Calcium is taken in the diet as calcium phosphate, carbonate, tartrate.
 About 40% of dietary calcium is absorbed from the gut.
 Absorption occurs in the first and second part of duodenum.
 Requires a carrier protein and helped by calcium-dependent ATPase.
 400mg is excreted through stools and 100mg is excreted through urine

14. SITE & MECHANISM
Absorption through the parts of duodenum Types of absorption
( 1 ) Simple diffusion
( 2 ) Active transport

15. SIMPLE DIFFUSION

16. ACTIVE TRANSPORT

17. CALCIUM REGULATION
By 3 main organs :
 1) Bone
 2) Intestine
 3) Kidney
By 3 main hormones :
 1) Parathyroid hormone (PTH)
 2) Vitamin D ( calcitriol )
 3) Calcitonin

19. ROLE OF PTH ON CALCIUM REGULATION
 PTH is secreted by two pairs of parathyroid glands.
 Parathyroid hormone is a single chain polypeptide containing 84 amino acids.
 It is initially synthesized as PreProPTH which is degraded as ProPTH and finally to
active PTH.
 The rate of formation & secretion of PTH are promoted by low Ca++ concentration.

21. ROLE OF CALCITRIOL ON CALCIUM
REGULATION
 On Bone – stimulates calcium uptake for deposition of calcium phosphate.
 On Intestine – increases intestinal absorption of Ca2+ and phosphate.
 On Kidneys – minimizing the excretion of Ca2+ and phosphate and hence enhancing
the reabsorption.

22. ROLE OF CALCITONIN ON CALCIUM
REGULATION
 Calcitonin is a peptide containing 32 amino acids.
 It is secreted by parafollicular cells of thyroid gland.
 The action of Calcitonin on calcium regulation is just antagonistic to PTH.
 Calcitonin promotes calcification of bone.
 Calcitonin decreases the bone resorption and hence increases the calcium excretion.
 It has a decreased influence on blood calcium.

23. EXCRETION OF CALCIUM
 The major site for calcium excretion is by kidneys.
 The rate of calcium loss and reabsorption at the kidney can be regulated.
 Regulation of absorption, storage and excretion of calcium results in maintenance of
calcium hemostasis.

24. • About 1,000 mg of calcium is excreted
daily. Out of this, 900 mg is excreted through
faeces and 100 mg through urine.
• Most of the filtered calcium is reabsorbed in
the proximal convoluted tubules and proximal
part of collecting duct.
• In distal convoluted tubule, PTH increases the
reabsorption.
• In collecting duct, vitamin D increases the
reabsorption and calcitonin decreases
reabsorption.

25. METABOLISM DISORDERS
Disorders of calcium metabolism includes:
 Hypercalcemia
 Hypocalcemia
 Hyperparathyroidism
 Hypoparathyroidism

26. HYPERCALCEMIA

28. Treatment:
• Calcitonin (Miacalcin) - This hormone from salmon controls calcium
levels in the blood.
• Calcimimetics - This type of drug can help control overactive
parathyroid glands. Cinacalcet (Sensipar) has been approved for
managing hypercalcemia.
• Denosumab (Prolia, Xgeva) - This drug is often used to treat people
with cancer-caused hypercalcemia who don't respond well to
bisphosphonates.

29. • Steroid (Prednisone) - If your hypercalcemia is caused by high levels of
vitamin D.
• IV Saline & furosemide for rapid correction - In case of emergency.
• Bisphosphonates - Intravenous osteoporosis drugs, which can quickly
lower calcium levels, are often used to treat hypercalcemia due to cancer.

30. HYPOCALCEMIA

33. A calcium infusion is indicated for severe
acute or symptomatic hypocalcemia, while
the standard mainstays of oral therapy are
calcium supplements and activated vitamin
D metabolites
Treatment:

34. HYPERPARATHYROIDISM
CAUSES:

35. SIGN AND
SYMPTOMS:

36. X-rays: showing resorptions
sub-periosteal
rugger jersey spine
pepper pot skull cystic brown tumours

37. Giant Cell Granuloma
Epulis
Loss of lamina dura,
pathognomonic oral change
in hyperparathyroidism
Panoramic image shows the loss of bone. The
radiopaque teeth standing out in contrast to the
radiolucent jaws

38. •Oral calcium supplements — as tablets, chews or liquid — can increase calcium
levels in your blood.
•High doses of vitamin D, generally in the form of calcitriol, can help your body
absorb calcium and eliminate phosphorus.
•Magnesium.
•Thiazide diuretics.
•Parathyroid hormone replacement
Treatment:

39. HYPOPARATHYROIDISM
There are different types of hypoparathyroidism, including acquired, autoimmune, congenital, and
familial types:
•Acquired: This is the most common type. It occurs after removal of or damage to the parathyroid glands,
either through surgery or an injury.
•Autoimmune: This is the second most common type of hypoparathyroidism and occurs because
the immune system mistakenly attacks the parathyroid gland or the parathyroid hormone.
•Congenital: This is a much rarer type of hypoparathyroidism that appears at birth. It is the result of gene
mutations in the parathyroid hormone process, or someone being born without parathyroid glands.
•Familial: If you have a family history of hypoparathyroidism, you have a higher risk of developing familial
hypoparathyroidism.

40. Signs and symptoms:
•Tingling and burning in your fingertips, toes and lips
•Fatigue and weakness
•Painful menstrual periods
•Patchy hair loss
•Dry, coarse skin
•Brittle nails
•Depression or anxiety
•Muscle aches or cramps in your legs, feet, face or
stomach
•Spasm on your muscle

41. Currently, the standard treatment for
hypoparathyroidism consists of activated vitamin D
(calcitriol) and calcium supplements. Some people
may also need magnesium supplementation.
Treatment:

42. CONCLUSION
• Disturbances in calcium excretion and transcellular shift result in deranged metabolism
accounting for abnormal serum levels. An understanding of calcium is required for the
clinician to evaluate disorders of the levels of calcium as well as metabolic & skeletal
disorders. Therefore, the dental observation of disturbances in tooth formation and
eruption pattern may be of crucial importance for the clinician.

43. REFERENCES
 Essential of medical physiology sembulingam ,5/e
 Davidson’s principles and practice of medicine, 19/e.
 Harrison principle of internal medicine,18/e.
 Shafer’s textbook of oral pathology ,7/e.
 Textbook of biochemistry by u. Satyanarayana, 2/E
 Burkett's oral medicine 11th edition
 Calcium and Phosphate Metabolism – Annual Review of Physiology Vol. 36: 361-390 A B Borle
 Oral manifestations of parathyroid disorders and its dental management, journal of dental and allied sci year : 2014
| volume : 3 | issue : 1
 J of applied oral sc. 2013 nov-dec; 21(6): 601–606