•Minerals

• 29 different types of elements in our body.• Divided into 4 Major Groups

• Group I:- C, H, O, N- Component of Macromolecules such as Carbohydrates, Proteins and Lipids

• Group II :- (Macro Elements)- Includes., Na , K , Cl ,Ca , P , Mg & S- Required in amount > 100 mg/day- Deficiency leads to fatal complications/death

• Group III :- (Trace Elements)

- Required in amount < 100 mg/day

- Includes., Co (Cobalt), Cr (Chromium), Cu (Copper), I (Iodine), Fe (Iron), Mn (Manganese), Mo (Molybdenum), Se (Selenium) & Zn (Zinc)

• Group IV:- (Additional Trace Elements)

- Exact role is unknown

- Cd (Cadmium), Ni (Nickel), Sn (Stensium),

Vn (Vanadium)

Metabolism of MineralsCommon minerals found active in body are

Na+, K+, Cl, Ca++ Fe++, P, Mg++, etc. Ca++, P, Mg, Constituent of bones and teethFe++:- Important element present in heme

compounds such as Hb , Cytochromes etc.Deficiency of Minerals result in disturbance

of Physical Structure, Metabolic processes and Normal functioning of body

• GENERAL FUNCTIONS OF MINERALAS1. Structural components of body i.e., They

perform building function e.g., Ca, P are used in Bone formation, F for Teeth, P, K, Cl & S for Tissues. S also for Hair, Nail; Fe for Hb; Cl for HCl secretion & I for Thyroid Hormones.

2. Acid/Base Balance:- [NaH2PO4/NaHPO4]

3. Regulates body fluids e.g in H2O Balance4. For the transport of Gases5. Responsible for Contraction & Relaxation6. As a Co-factor of certain Enzymes

CALCIUMCALCIUM

Dietary SourcesDietary Sources• Milk and milk product------Best dietary source• Other good Sources are Egg yolk, Beans, Nuts

& hard drinking water .• Leafy vegetables:- (also contain oxalate &

benzoate), which are insoluble and thud decrease its absorption

Body Distribution

• Human body contain about 1 Kg Ca2+

• 99 % in bones

• 1 % in extra cellular fluid .

Bone Ca2+:

In form of Hydroxyappetite Crystal [(Ca)6(PO4)3(OH)]

Bones perform two main functions:-

1. Mechanical Functions

2. Reservoir of Ca2+

1 % of bone Ca 2+ & 1 % of periosteal space Ca2+ is freely exchangeable with E.C.F & this is called Miscible Pool of Ca2+

This exchange is regularized by P.T.H, Calcitriol,

& also by Calcitionin

Calcium in Plasma

[9 – 11 mg /dL]

R.B.C contains very little Ca2+

Extracellular concentration = 5m mol/L

Intracellular concentration = 0.1 – 10 µ mol/L

Ca2+ in plasma Exists in 3 forms

A. Protein Bound Ca2+ [47%]

Mostly albumin (80%), Serum globulin (20%) and

Normal Level is 3.4 – 4.4 mg/dL

B. Complex Calcium [6%]

Complexed with plasma anions e.g., Citrate & Phosphates etc. (0.5 – 0.7 mg/dL)

C. Ionized, Diffusible or Free Ca2+ [47%]

Biologically active from

• All 3 forms of Ca2+ in plasma remain in equilibrium with each other

• Solubility product of Ca2+ i.e., Ca x P in serum is a constant value

• It gives protection against precipitation of Ectopic Calcification

Absorption:

• Ca2+ is taken in diet principally as calcium phosphate, carbonates & tartarate.

Only 40% of dietary Ca2+ is absorbed mainly from duodenum & first half of jejunum against electrical and concentration gradients

Mechanism:

Two mechanisms for absorption

1. Simple diffusion

2. Active transport process

Both the process required Calcitriol and also a Ca2+ dependent ATPase

Vitamin – D

Vit. D2: Ergocalciferol (Vegetables)

Vit. D3: Cholecalciferol (Animals origin/Inactive)

25 – Hydroxylase (Liver)

25–Hydroxycholecalciferol (Inactive)

1- α Hydroxylase

1, 25–Dihydroxy-Cholecalciferol/Calcitriol

(In Kidney)

Factor affecting absorption of Ca2+:

1. pH of Intestine Acidic pH favors/increases absorption because

Ca2+ salt particularly PO4-3, carbonate are quite

soluble in acidic solution. Alkaline pH decreases the absorption due to

form-ation of insoluble Tricalcium PO4-3

2. Composition of Diet High protein diet: Increases absorption

because a.a (lysine & arginine) increases solubility of Ca2+ salt

F. Acids decreases insoluble calcium soap Sugars & organic acids increases absorption Phytic acids decreases absorption Oxalates present in vegetables also decreases

the solubility & hence decreases its absorpt.

3. Minerals

a) PO4-3: Excess of PO4

-3, decreases Ca2+ absorption

b) Ca:P Ratio: For optimal absorption of Ca2+ ideal ratio of Ca2+ to PO4

-3 is 1:1 and it should not be more then 2:1 and not less than 1:2

c) Fe in diet: forms insoluble Ferric phosphates which decrease absorption

d) Vit–D: Increases absorption & serum Ca2+ level

4. State of Health & Aging:

- Healthy adult= 40% of dietary Ca+2

- above age of 60 years there is a gradual decline

- Ca+2 deficiency increases absorption probably through increase Parathyroid activity

e) Bile salts: Increases Ca2+ absorption by

i. Enhanced solubility of Ca2+ salts

ii. Increases Vit–D absorption

iii. Increases Digestion & absorption of fats

5. Hormones

(A) P.T.H:

1 Stimulates “1-α Hydroxylase’’ enzyme in kidneys & increase synthesis of Calcitriol which increase Ca2+ absorption from gut

2 Direct effect on bone

3 Direct effect on kidney.

(B). Calcitonin:

Increased level inhibits “1-α Hydroxylase’’ & decrease calcitriol synthesis & decrease Ca2+ absorption. Used in treatment of Hypercalcaemia caused by hyperparathyroidism & Vit–D intoxication

(C) Glucocorticoids:

Decrease Ca2+ absorption by decrease intestinal transport of Ca2+

• Factors affecting plasma Ca2+ Levela. Amount of Ca2+ absorbed from GITb. P.T.Hi. Increases mobilization of Ca2+ from bones

(Largest Effect)(ii) Increase absorption in gut (Long Term Effect)

(Increase the synthesis of Calcitriol)(iii) Decrease execration by kidney (Most Rapid

Action) c. Inverse relationship b/w plasma Ca2+ & Pi. When

plasma Ca increase, P decrease & vice versa so product of plasma Ca2+, & Pi remain constant at 30–40 mg/dL in adult 40–55 mg/dL in children.

[Plasma Ca2+ level falls in kidney diseases due to retention of PO4

-3 so increase PO4-3,

decreases Ca2+]

d. Serum Protein Level: 1 gm serum protein bound 0.84 mg of Ca2+. However ionized Ca2+ remain normal so there will be no Tetany, when there is deficiency of protein

e. Calcitonin: It decrease serum Ca2+ by antagonizing the action of PTH. It decrease bone resorption & increase deposition of Ca2+ in bones (It inhibits 1-α Hydroxylase)

Mechanism of action of Calcium:

Intracellular Ca2+ binds Calmodulin (4 binding Sites)

Ca–Calmodulin Complex

Active Calmodulin Kinase

Catalyze formation of Phosphoprotein from Protein [Phosphoprotein exert their

Physiological & Biological response]

• Functions of Calcium1. Calcification of Bones and Teeth2. Play imp. Role in Blood Coagulation3. A number of enzymes are activated by

blood Ca2+ e.g., Lipase, Succinic dehydrogenase & few Proteolytic enzymes

4. Play role in muscle contraction5. Transmission of nerve impulse6. Help in acid base balance7. Essential for release of certain hormones &

also for intracellular action of certain hormones

8. Essential for permeability of gap–junction

9. Membrane integrity & membrane transport

Excretion

Mainly excreted in faeces (0.4–0.8 g/day) , which is unabsorbed form. Urinary loss is 150 – 200 mg/day. Men working in extreme heat may loss 100 mg/hr of Ca2+

Requirement: [1g/day]

Increase in pregnancy, lactation, & in children

• Hypercalcaemia: Various causes

• Ca get deposited in various body tissues resulting in their malfunction

• Hypocalcaemia:

Low plasma ionized Ca2+:--- Tetany, characterized by spontaneous firing of Nerve fiber. Increase Cardiac contractibility, retardation of relaxation of muscles etc. Corpopedal Spasm

If untreated my lead to death. Spasm due to respiratory muscles. I/V Calcium is treatment