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.