MINERALS AND TRACE ELEMENTS

• Minerals are elements of the periodic table

• More than 25 have been isolated

• Minerals are elements other than carbon, hydrogen, nitrogen, and oxygen which are needed for good health.

• Minerals make up about 4 to 5% of body weight

• Many minerals are found in ionic form

Minerals work in combination with each other and with other nutrients

• Two categories:

• macrominerals > 0.005%

• microminerals < 0.005%

• Macrominerals are essential at levels of 100mg or more per day for human adults

• Microminerals are often referred to as trace elements

Functions of minerals

• Provide a suitable medium for cellular activity

• Play a primary role in osmotic phenomenon

• Involved in acid base-balance

• Confer rigidity and hardness to certain tissues (bones and teeth)

• Become part of different compounds

Metalloenzymes:

Examples of metalloenzymes:

– superoxide dismutase (Zn and Cu)

– carboxypeptidase A (Zn)

– carbonic anhydrase (Zn)

– cytochrome oxidase (Fe and Cu)

– xanthine oxidase (Co and Fe)

1)Sodium (Na)

• Sodium is the principal cation in extracellular fluids

• Whole blood contains 160mg/dl

• Plasma contains 330mg/dl

• Regulate in Kidney

• Excrete through urine

for adults: 1.1 to 3.3 gm/day

food sources: table salt, salty foods (potato chips, pretzels, etc.), baking soda, milk

Functions include:

osmotic equilibrium

acid-base balance

carbon dioxide transport

cell membrane permeability

muscle irritability

• absorption and metabolism:

– readily absorbed

– excreted in the urine and sweat

– aldosterone increases reabsorption in renal tubules

• sodium deficiency:

– dehydration

– acidosis

– tissue atrophy

• sodium excess:

– edema

– hypertension

Factors Influnece Na+ Excretion

Glomerular filtration

Tubular Reabsorption

Hormones

Depletion

Potassium (K)

• Potassium is the principal cation in intracellular fluid(muscle)

• Food sources: vegetables, bananas,citrus, tomato, grains, meat, milk, pretzel

• absorption and metabolism:

– readily absorbed

– secreted by kidney (also in sweat)

• for adults: 1.5 - 4.5 gm/day

• Functions:

– buffer constituent

– acid-base balance

– water balance

– membrane transport

– neuromuscular activity

– Enzymes

– glycogenesis

• excess (hyperkalemia)

– causes:

• sudden increased intake

• severe tissue burns

• Renal failure

• acute and chronic acidosis

– symptoms:

• weakness of skeletal muscles (impaired respiration

• cardiac anomalies

• deficiency (hypokalemia)

– causes:

• increased renal excretion

• Diuresis

• alkalosis

• severe vomiting and diarrhea

• cutaneous losses via perspiration

– symptoms:

• weakness of skeletal muscles (impaired respiration

• weakness of smooth muscles

• cardiac anomalies: cardiac arrest

Treatment of hyperkalemia

• reverse cardiotoxic effects:

– calcium gluconate IV

• increase potassium uptake by cells:

– dextrose (IV)

– insulin (IV)

– sodium bicarbonate (IV)

• remove excess potassium from the body:

– sodium polystyrene sulfonate (Kayexalate)

Calcium (Ca)

• the most abundant of the minerals in the body

• needed by all cells, make 1% of body weight

• found in largest amounts in bones (97%)

• Milk, egg yolk, leafy vegetable

• Non-diffusible, diffusible

– adult: 800 mg/day

– pregnacy and lactation: 1200 mg/day

• controlled by parathyroid hormone (PTH), calcitonin and vitamin D

• maintained at a concentration of 9-11mg/dl in plasma

• about 1/2 is in the ionized form in serum

• the other 1/2 is bound to protein (calcium citrate complex)

• Function Of Calcium:

– structural unit of bones and teeth

– contraction and relaxation of muscles

– stabilizes nervous tissue

– required for blood clotting

– activates various enzymes (glycogen phosphorylase kinase, salivary and pancreatic amylase)

– exocytosis

• Calcium absorption:

– variable due to insoluble salts:

• phosphate

• Carbonate

• Sulfate

• forms calcium soaps with fatty acids

• Bile salt

• Acid pH

• Parathyroid hormones

• calcitonin

• Excretion:

• urine and feces

• enhanced by lack of vitamin D and ingestion of large quantities of proteins (acid urine)

Chloride (Cl)

• an essential anion

• closely connected with sodium in foods, body tissues and fluids and excretions

• readily absorbed along with sodium

• excreted mainly in the kidneys (~ 2% in feces and ~ 4-5% in perspiration

• important for osmotic balance, acid-base balance and in the formation of gastric HCl

• Deficiency of chloride:

• hypochloremic alkalosis -extreme lack or loss of chloride

• Hypovolemia-Low blood volume

• pernicious vomiting

Phosphorus

• Phosphorus is the second most abundant mineral in the body (22% of total mineral content)

• 80% is structural:

• 20% is very active metabolically:

• Source; milk, cheese, eggs, beans, fish

• RDA for phosphorus is established on the basis of a 1:1 relationship with calcium

Absorption

• By food in form of inorganic phosphate

• Excessive intake of iron

• Vitamin D

• Ca:P Ratio

Functions

• Take part in formation of bones

• High energy compounds, ATP, GT etc

• Constituent of DNA, RNA

• Phospholipids

• Deficiency : Increased Plasma Calcium concentrations; Increased Parathyroid concentrations.

• Toxicity: Excessive ingestion may cause Osteoporosis and severe diarrhea.

Magnesium (Mg)

• Present in intracellular fluids

• 50% of total amount in bone

• 45% in muscle and nervous tissue

• 5% in extracellular fluids

• Absorb in small intestine

Food sources: Grains, Nuts, Seeds, Milk, Green vegetables, Seafood, rice, meat

• RDA: 350 mg/day

– pregnancy and lactation: 450 mg

Functions:

• Bone structure;

• Stabilizes the ATP intracellular structure;

• Co-enzyme in 80% of all enzymes,

• Kreb’s Cycle and reactions with protein and nucleic acid synthesis;

• Involved in thyroid/parathyroid production.

Toxicity: May cause CNS depression, disorientation, psychotic behavior, convulsion

Hypomagnesemia

CNS

– disorientation, psychotic behavior, convulsions

Neuromuscular system:

– magnesium has a direct depressant effect on skeletal muscle

TRACE ELEMENTS

Copper

• important trace mineral

• Adult R.D.A.: 2 mg / Day

• Adult has 100-150mg

• Tissue Stores: Liver, Brain, and Bile.

• sources

• liver, shellfish, whole grains, cherries, legumes, nuts

• Absorption/Excretion

• 5-10% Absorb, remaining excrete in feces

• component of several enzymes:

• tyrosinase

• amine oxidase

• cytochrome C oxidase

• dopamine beta hydroxylase

• copper/zinc superoxide dismutase

• Copper present as component of

Ceruloplasmin

Erythrocuperin

Cerebrocuperin

• Important for iron absorption and utilization

Deficiency

decreased iron absorption

Osteoporosis

bone demineralization

failure of erythropoiesis

Toxicity: Increased levels may lead to mental / physical fatigue; Depression; Irritation of the gastrointestinal tract, Wilson’s disease

ZINC

Adult R.D.A.: 15 mg / Day

Dietary Sources: Meat, Eggs, Seafood, Milk, Grains, Spinach, Soybeans, and Sunflower seeds.

Tissue Stores: Prostate, Skin, and Retina.

Functions: Necessary co-enzyme in over 200 different enzyme systems;

Associated with cholesterol, protein, and energy metabolism;

Required for nucleic acid synthesis and carbon dioxide transport;

Essential for normal growth,

Deficiency : Impaired RNA / DNA and protein synthesis; Chronic infections; Decrease growth patterns and sexual maturation; Decreased senses of taste and smell.

Toxicity: Impaired immune response; Diaphoresis; Chronic nausea and vomiting

Iron (Fe)

• 2 types of body iron

– heme iron

• hemoglobin, myoglobin, catalases, peroxidases, cytochromes (a, b and c, cytochrome P450

– non-heme iron

• ferritin, hemosiderin, hemofuscin, transferrin, ferroflavoproteins, aromatic amino acid hydroxylases

Iron absorption

Average diet contains 10 - 15 mg of iron per day

A normal person absorbs 5 -10% of this iron or 0.5 - 1.0 mg daily

Iron absorption increases in response to low iron stores

occurs in upper part of small intestine

About 10% of food iron is absorbed

Requires copper

Food iron

1)heme iron

– meats

– poultry

– fish

20-23% of heme-iron is absorbable

2)non-heme iron

– vegetables

– fruits

– legumes

– nuts

– breads and cereals

Only 3% on non heme iron is absorbed

R.D.A.: 10 mg / Day

Dietary Sources: Meats, Spinach, Soybeans, Dried legumes, Clams, Oysters, Dried fruits, and Egg yolk.

Functions: Oxygen transport in blood and muscle tissue; Involved in electron transport and oxidative phosphorylation; Helps improve muscle function.

Iron distribution and storage

• carried in blood stream via transferrin (a b globulin)

• stored in 2 forms:

• ferritin (a water soluble complex consisting of a core of ferric hydroxide and a protein shell (apoferritin)

• hemosiderin (a particulate substance consisting of aggregates of ferric crystals)

• Stored in liver, spleen, bone marrow, intestinal mucosal cells and plasma

IRON DEFICIENCY

Initial symptoms are vague and ill-defined

• easy fatigability

• lack of appetite

• headache

• dizziness

hypochromic-microcytic anemia

• microcytosis (small RBCs)

• hypochromia (poor fill of hemoglobin)

• poikilocytosis (bizarre shapes)

• anisocytosis (variable sizes)

MANGANESE

Adult R.D.A.: 2 - 5 mg / Day

Dietary Sources: Whole grain cereals, Leafy vegetables, Nuts and Tea.

Tissue Stores: Liver, Kidney, Pineal / pituitary glands, and Pancreas.

Functions: Associated with enzymes involved in metabolism, growth / maintenance of connective tissue, bone and cartilage;

Implicated in Melanin production,

Fatty Acid synthesis,

the formation of Membrane phospholipids and Prothrombin.

Needed for Vitamin C absorption.

Deficiency: Impaired glucose metabolism; Mucopolysaccharide and Lipopolysaccharide deficiencies; Psychiatric disorders; Decreased mental activity and Neurologic disorders.

Toxicity: High doses may cause hypertension and irreversible neurologic disorders; May interfere with the metabolism of other metals / minerals.

SELENIUM

Adult R.D.A.: 25 – 200 mg / Day

Dietary Sources: Seafood, Liver, Kidney, Whole grains, Vegetables, Garlic and Brazil nuts.

Tissue Stores: Red blood cells, Liver, Spleen Heart, and Nails.

Functions: A key component of the enzyme Glutathione Peroxidase which protects tissues, especially cell membranes from free radical pathology; Stimulates antibody production and protein synthesis in the Liver; Activates RNA and DNA.

Deficiency : Liver disease, Possibly deficient in Sudden Infant death Syndrome; Protein calorie malnutrition; Aspermatogenesis; Cataracts, Cancer; Cardiovascular disease.

Toxicity: Liver failure; Inhibits cell mitosis; Hair loss; Chronic arthritis; Diabetes Mellitus; Renal damage

Iodine

• Iodine is necessary for the formation of thyroid hormones

• Deficiency of iodine is manifested by a goiter (enlargement of the thyroid gland)

• Salt water fish and seaweeds are a good source of iodine

• To prevent the development of endemic goiter, tablet salt has been spiked with sodium iodide

Fluorine

• Main sources include drinking water and plants

• Average daily intake: 1.5 – 4.0 mg/day

• Considered essential because of its beneficial effect on tooth enamel

• Benefits include: less dental caries, stronger bones, reduction in osteoporosis and calcification of the aorta

• In large quantities it is deleterious to teeth; dental fluorosis: dull white patches on teeth

CHROMIUM

• R.D.A: 50 - 200 mg / Day

• Dietary Sources: Meat products, Cheese, Whole grains, Milk, Eggs, yeast, Mushrooms, and Peppers.

• Tissue Sources: Skin, Fat, Adrenals, Brain, Spleen, and Muscle.

• Functions: Essential part of glucose tolerance factor required in insulin potentiation; Stimulates both fatty acid and cholesterol synthesis.

COBALT

• D.A.: 3 - 5 mg / Day

• Dietary Sources: Kidney, Beef, Lamb, Veal, Poultry, Ocean fish, Milk, Cheese and Eggs.

• Tissue Stores: Bone, Muscle, and Kidney

• Functions: Intrinsic part of Vitamin B-12; Required for the synthesis of Methionine from Homocysteine and the conversion of Methylmalonic acid to Succinyl CoA for fatty acid synthesis; Necessary for Folic Acid synthesis.