DIETARY MINERALS Dr Usman Shahnawaz Minerals Inorganic elemental

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DIETARY MINERALS Dr. Usman Shahnawaz

DIETARY MINERALS Dr. Usman Shahnawaz

Minerals Inorganic elemental atoms that are essential nutrients. Not changed by digestion or metabolism.

Minerals Inorganic elemental atoms that are essential nutrients. Not changed by digestion or metabolism.

Dietary minerals n 1. 2. Dietary minerals refers to inorganic compounds necessary for life

Dietary minerals n 1. 2. Dietary minerals refers to inorganic compounds necessary for life and good nutrition Some are scientific minerals like salt Others are elements like K , Ca , Fe, Zn , Mg and Cu

Functions of Minerals n n n Some participate with enzymes in metabolic processes (cofactors)

Functions of Minerals n n n Some participate with enzymes in metabolic processes (cofactors) Some have structural functions (Ca, P in bone; S in keratin) Acid-base and water balance (Na, K, Cl) Nerve & muscle function (Ca, Na, K) Unique functions (e. g. , heme, B 12, thyroid hormones)

Classification n n Contaminant Minerals Required in very minute amount If taken in large

Classification n n Contaminant Minerals Required in very minute amount If taken in large amount or stored in excess becomes toxic Includes : n n Lead Arsenic Tin Boron

The Major Minerals: an Overview n n Macrominerals Humans need >100 mg/d n ��

The Major Minerals: an Overview n n Macrominerals Humans need >100 mg/d n �� Calcium n �� Phosphorus n �� Magnesium n �� Sodium n �� Chloride n �� Potassium

Micro Minerals : an Overview n Human need < 100 mg / d n

Micro Minerals : an Overview n Human need < 100 mg / d n n n n Fe Zn Cu F Se Co Iodine

Bioavailability & Regulation of Minerals n Bioavailability ( Absorption of chemicals and substances in

Bioavailability & Regulation of Minerals n Bioavailability ( Absorption of chemicals and substances in humans and other animals) n Influenced by genetics, aging, nutritional status & other food compounds Absorption n Small & Large Intestine Regulation n Kidneys & Small intestine

Sources of Minerals 1. 2. 3. 4. Naturally occurring in food Added in elemental

Sources of Minerals 1. 2. 3. 4. Naturally occurring in food Added in elemental or mineral form like Ca. CO 3 , Na. Cl Some of these additives come from natural sources like ground oyster shells Sometimes minerals added to diet separately from food as vitamin & mineral supplements

Sources of Minerals

Sources of Minerals

Factors Affecting Requirements n n n Physiological state/level of production Interactions with other minerals

Factors Affecting Requirements n n n Physiological state/level of production Interactions with other minerals Tissue storage n n n �� Bone, Liver �� Specific proteins to hold and transport Form fed n n �� inorganic vs organic forms �� Na selenite vs Na selenate vs selenomethionine

Organic Vs Inorganic sources n n n Dietary source of minerals can be organic

Organic Vs Inorganic sources n n n Dietary source of minerals can be organic like plants but they themselves are inorganic Minerals in ionic form are best absorbed Inorganic or metallic source of minerals can be toxic like heavy metals Minerals in their inorganic form are not easily absorbed Stored in tissues & large amounts are toxic

Deficiencies and Excesses n Most minerals have an optimal range n n �� Below

Deficiencies and Excesses n Most minerals have an optimal range n n �� Below leads to deficiency symptoms �� Above leads to toxicity symptoms Mineral content of soils dictates mineral status of plants (i. e. , feeds) May take many months to develop n �� Time impacted by body stores

CALCIUM

CALCIUM

Calcium n Most abundant mineral in animal tissues n n 99 % Ca in

Calcium n Most abundant mineral in animal tissues n n 99 % Ca in skeleton Present in blood and other tissues Young adult contains average of 1100 g Ca Normal plasma concentration of Ca is 9— 12 mg / dl or 5 m. Eq / L

Food Sources n Milk and dairy products n n n �� High amounts ��

Food Sources n Milk and dairy products n n n �� High amounts �� High bioavailability (fortified with vitamin D) Green leafy vegetables n �� Poor absorption

Daily Requirements n n Infants 210 – 270 mg Children 1 to 8 years

Daily Requirements n n Infants 210 – 270 mg Children 1 to 8 years 500– 800 mg Adult female 1000– 1300 mg Adult male 1000– 1300 mg

Calcium Regulation Three hormones involved in regulation Vit D 3 from kidney n 1.

Calcium Regulation Three hormones involved in regulation Vit D 3 from kidney n 1. n n n Steroid hormone Formed from Vit D by successive hydroxylation in liver and kidney It increases Ca absorption from intestine

Calcium regulation 2. Parathyroid Hormone (PTH ) n From parathyroid gland n Mobilizes Ca

Calcium regulation 2. Parathyroid Hormone (PTH ) n From parathyroid gland n Mobilizes Ca from bone & increases urinary phosphate excretion 3. Calcitonin n From thyroid gland n Inhibits bone resorption n the mobilization of Ca from bone

Calcium Regulation n �� PTH and Vitamin D 3 act to increase plasma Ca,

Calcium Regulation n �� PTH and Vitamin D 3 act to increase plasma Ca, while calcitonin acts to decrease plasma Ca

Calcium Regulation n Ca is partly bound with proteins and partly diffusible Plasma or

Calcium Regulation n Ca is partly bound with proteins and partly diffusible Plasma or serum Ca Non- diffusible n Cannot be dialyzed out n In firm combination with plasma proteins specially albumin n Level is 3. 4 to 4. 4 mg / dl Diffusible Sub-divided into two

Calcium Regulation Diffusible Calcium Ionized Calcium n n Level is 5. 45 to 6.

Calcium Regulation Diffusible Calcium Ionized Calcium n n Level is 5. 45 to 6. 23 mg/dl Physiologically active Increases in hyper-parathyroidism and vice versa Level below 4. 3 mg/dl causes tetany

Calcium Regulation Diffusible Calcium Complexed Calcium n Level less than 0. 6 mg/dl n

Calcium Regulation Diffusible Calcium Complexed Calcium n Level less than 0. 6 mg/dl n In complex form with plasma anions like citrate and phosphate

Ca Regulation Calcium in Bones 1. n n Readily exchangeable reservoir Regulates plasma Ca

Ca Regulation Calcium in Bones 1. n n Readily exchangeable reservoir Regulates plasma Ca Approximately 500 mmoles / day of Ca moves into and out of the readily exchangeable reservoir present in the bone

Calcium Regulation Calcium in Bones 2. Stable or slowly exchangeable Ca n Concerned with

Calcium Regulation Calcium in Bones 2. Stable or slowly exchangeable Ca n Concerned with bone remodeling n Ca interchange between plasma and stable pool is only about 7. 5 mmol / day

Calcium Regulation n n Large amount of Ca is filtered in kidneys 98 to

Calcium Regulation n n Large amount of Ca is filtered in kidneys 98 to 99 % reabsorbed 60 % reabsorption in proximal tubules Remainder in ascending loop of Henle and distal tubules Distal tubular reabsorption regulated by parathyroid hormone

Regulatory Functions of Calcium n Stimulates blood clotting n n Muscle contraction n n

Regulatory Functions of Calcium n Stimulates blood clotting n n Muscle contraction n n Ca activates myosin- ATP complex, motors sliding action between actin and myosin Transmission of nerve impulses n n factor IV blood coagulation Ca necessary for transmission of nerve impulses from presynaptic to postsynaptic region Vision n Ca regulates cyclic GMP in retinal rods & has role in adaptation

Regulatory Functions of Calcium n n n Regulation of blood glucose n Role in

Regulatory Functions of Calcium n n n Regulation of blood glucose n Role in secretion of insulin Cell differentiation Cofactor for energy metabolism n Cofactor for many enzymes Secretion of hormones n Insulin , PTH, Calcitonin Ca and cyclic AMP second messengers of different hormones n Glucagon

Calcium Functions

Calcium Functions

Structural Functions of Calcium: Bones & Teeth n Bones n Osteoblasts n n n

Structural Functions of Calcium: Bones & Teeth n Bones n Osteoblasts n n n Bone formation Osteoclasts n Breakdown of older bone �� Hydroxyapatite n Large crystal-like molecule

Calcium Deficiencies n Rickets n n Osteomalacia (osteoporosis) n n In adult animals Milk

Calcium Deficiencies n Rickets n n Osteomalacia (osteoporosis) n n In adult animals Milk fever (parturient paresis) n n in growing Child in lactating animals Tetany

Calcium and Bone Health Bone growth is greatest during “linear growth” n �� Peaks

Calcium and Bone Health Bone growth is greatest during “linear growth” n �� Peaks out at around age 30 n Calcium in bones used as reservoir for other needs. n �� Maintains blood calcium homeostasis n

Calcium Toxicity n n n Deposition in soft tissue Impaired kidney function Interference with

Calcium Toxicity n n n Deposition in soft tissue Impaired kidney function Interference with other nutrient absorption n Iron & zinc

Phosphorus n Total body phosphorus n n Mostly combined with Ca in bone Occurrence

Phosphorus n Total body phosphorus n n Mostly combined with Ca in bone Occurrence n n 1 – 1. 5 kg Component of each and every part of living system i. e. , Cell Distribution n 80 % in bones and teeth 10 % in lipids, proteins and carbohydrates 10 % in different compounds in blood and muscles

Phosphorus n Daily Requirements n n n Infants Children Male ( adults ) Females

Phosphorus n Daily Requirements n n n Infants Children Male ( adults ) Females During pregnancy 300 – 500 mg 500 – 1200 mg Total plasma phosphorus 12 mg / dl n n 2 / 3 in organic compounds Remaining inorganic as HPO 4 & H 2 PO 4

Phosphorus n n n Dietary Sources n Milk n Cheese n Liver n Kidney

Phosphorus n n n Dietary Sources n Milk n Cheese n Liver n Kidney Recommended Ca / P ratio 1 : 1 Food adequate in Ca also adequate in P

Phosphorus n Distribution n Serum n n n Whole blood 40 mg / dl

Phosphorus n Distribution n Serum n n n Whole blood 40 mg / dl Product of Ca * P must be 10 * 5 = 50 mg / dl Children Adults Muscle Nerve Bone & teeth 4 – 7 mg / dl 3 – 7 mg / dl 170 – 250 mg / dl 360 mg / 100 g tissue 3200 mg /100 g tissue

Metabolism & Regulation of Phosphorus in the Body n Small intestine absorption n Concentrations

Metabolism & Regulation of Phosphorus in the Body n Small intestine absorption n Concentrations controlled by: n n n Vitamin D-dependent active transport �� Simple diffusion �� Calcitriol, PTH, calcitonin P is filtered in glomeruli 80 – 85 % filtrate reabsorbed by proximal tubules by active transport

Functions of Phosphorus Constituent of Phospholipids like lecithins, cephalins, plasmalogens etc n Component of:

Functions of Phosphorus Constituent of Phospholipids like lecithins, cephalins, plasmalogens etc n Component of: n n n �� DNA & RNA �� ATP Protein synthesis n Role in formation of bones and teeth n

Functions of Phosphorus n n n Energy metabolism like esters with sugars as glucose

Functions of Phosphorus n n n Energy metabolism like esters with sugars as glucose 6 phosphate, fructose 6 phosphate Maintenance of blood p. H as phosphate buffer ( ICF ) Important constituent of cell membranes

Phosphorus Toxicity n n Mineralization of soft tissues Interference with absorption of Zinc &

Phosphorus Toxicity n n Mineralization of soft tissues Interference with absorption of Zinc & magnesium May cause kidney stones Very high levels n Coma n Cardiac arrest