MINERALS

Dr. Vijay Marakala, MBBS, MD.

Assistant professor BIOCHEMISTRY SIMS & RC

MINERALS

Minerals are inorganic compounds that are required for the body as one of the nutrients

MINERALS

Macrominerals Required in excess of

100mg/day

Ca++, P, S, Mg, Cl, Na, K.

Microminerals Required in amounts less than 100mg/day

Fe, Cu, Zn, Mo, I, Fl, Cr, CO, Mn

MINERALS

Calcium Phosphorous Iron Copper

Iodine Zinc Fluoride Magnesium

Manganese Selenium

MINERALS

CALCIUM O

BJEC

TIVE

S Sources and RDA

Metabolism of calcium

Functions of calcium

Regulation of plasma calcium

Disorders of calcium metabolism

CALCIUM

Calcium is the most abundant mineral in the body

Human body contain about 1-1.5 kg of calcium

SOURCES OF CALCIUM

DAILY REQUIREMENTS OF CALCIUM

Children 1000mg/day

Adults 500mg/day

Pregnancy and lactation1500mg/day

METABOLISM OF CALCIUM

Absorption Factors

affecting absorption

Mechanism of absorption

Excretion of calcium

Distribution and storage

METABOLISM OF CALCIUM - ABSORPTION

Site

Efficiency

Upper small

intestine

20-30% of dietary Ca

FACTORS AFFECTING CALCIUM ABSORPTION

Calcium absorption is increased by

CalcitriolPTHHigh protein dietOptimum Ca:P ratioAcidic pHBile salts

Absorption is decreased by

Alkaline pHPhytates and oxalatesSteatorrheaVitamin D deficiencyExcess phosphate in diet

MECHANISM OF CALCIUM

ABSORPTIONCalcium

absorption occurs by 1,25(OH)2D3

mediated mechanism.

EXCRETION OF CALCIUM

Stools Unabsorbed calcium in

the diet60 – 70%

Urine

50-200mg/day

Sweat

15mg/day

DISTRIBUTION AND STORAGE OF CALCIUM

Human body contain

about 1-1.5 kg of calcium

99% present in bone and teeth

1% in soft tissue and extracellular fluid

Plasma calcium : 9-11mg/100ml

FUNCTIONS OF CALCIUM

Formation of bone and teeth

Nerve conduction

Muscle contraction

Activation of enzymes

Blood coagulation Secretion of hormones

As a second messenger

Action on myocardium

REGULATION OF ENZYME ACTIVITY

Ca++ activates • Glycogen

phosphorylase kinase

• Amylase • PDH, IDH and α-

KGDH

Ca++ Inhibits • Pyruvate kinase• Trypsin

REGULATION OF PLASMA CALCIUM

50%40%

10%

%

Free or ionized calcium Protein boundcomplex with anions

REGULATION OF PLASMA CALCIUM

3 Organs

Gut

Bone

Kidney

3 Hormones

Calcitriol

PTH

Calcitonin

DISORDERS OF CALCIUM METABOLISM

HypocalcemiaHypercalcemia

HYPOCALCEMIA

Causes Features Treatment

HYPOCALCEMIA CAUSES Inadequate intake

Impaired absorption

Increased excretion

Magnesium deficiency

Acute pancreatitis

HYPOCALCEMIA - FEATURES Muscle cramps

and tetany

Laryngospasm

Convulsion

Cardiac arrhythmias

Prolongation of QT interval

Cataract

Chronic hypocalcemia

HYPOCALCEMIA – SIGNS OF TETANY

Contraction of facial muscle in response to tapping the facial nerve

Chvostek’s sign

Carpal spasm occurring after occlusion of the brachial artery with BP cuff for 3 min

Trousseau’s sign

HYPOCALCEMIA - TREATMENTSevere symptomatic

cases

Intravenous Calcium gluconate

Asymptomatic cases

Calcium carbonate

Vitamin D

HYPERCALCEMIA

Causes Features

Treatment

HYPERCALCEMIA CAUSES Increased intake

Increased absorption

Decreased excretion

Malignancy

HYPERCALCEMIA - FEATURESFEATURES Metastatic calcification

Neurological symptoms

Renal symptoms

Gastrointestinal symptoms

Cardiac arrhythmias

HYPERCALCEMIA - TREATMENT

Treatment of primary disease

Induction of natriuresis

Calcitonin