• 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 Minerals Common minerals found active in body are Na+, K+, Cl, Ca++ Fe++, P, Mg++, etc. Ca++, P, Mg, Constituent of bones and teeth Fe++:- 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 MINERALAS• 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.• Acid/Base Balance:- [NaH2PO4/NaHPO4]• Regulates body fluids e.g in H2O Balance• For the transport of Gases• Responsible for Contraction & Relaxation• As a Co-factor of certain Enzymes
Dietary 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 absorptionBody 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:-• Mechanical Functions• 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/LCa2+ in plasma Exists in 3 forms• Protein Bound Ca2+ [47%]Mostly albumin (80%), Serum globulin (20%) andNormal 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 gradientsMechanism:Two mechanisms for absorption• Simple diffusion• Active transport process
Both the process required Calcitriol and also a Ca2+ dependent ATPase Vitamin – DVit. 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+:2. 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 PO4-32. 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.5. Minerals• PO4-3: Excess of PO4-3, decreases Ca2+ absorption• 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 absorptiond) Vit–D: Increases absorption & serum Ca2+ level4. 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- Enhanced solubility of Ca2+ salts- Increases Vit–D absorption- Increases Digestion & absorption of fats5. Hormones(F) P.T.H:• Stimulates “1-α Hydroxylase’’ enzyme in kidneys & increase synthesis of Calcitriol which increase Ca2+ absorption from gut• Direct effect on bone• 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+ Level• Amount of Ca2+ absorbed from GIT• P.T.H• Increases mobilization of Ca2+ from bones (Largest Effect)• Increase absorption in gut (Long Term Effect) (Increase the synthesis of Calcitriol)• 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+]• 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• 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 Calcium2. Calcification of Bones and Teeth3. Play imp. Role in Blood Coagulation• A number of enzymes are activated by blood Ca2+ e.g., Lipase, Succinic dehydrogenase & few Proteolytic enzymes• Play role in muscle contraction• Transmission of nerve impulse• Help in acid base balance• Essential for release of certain hormones & also for intracellular action of certain hormones
1. Essential for permeability of gap–junction2. Membrane integrity & membrane transportExcretion 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 SpasmIf untreated my lead to death. Spasm due to respiratory muscles. I/V Calcium is treatment