Essential Trace Minerals Trace elements or micro-minerals Inorganic nutrients required by humans in very small amountsfrom micrograms (o.oo1 mg) to no more than a few mg - less than 100 mg/day Essential for humans with vital functions to avoid a deficiency disease. Mn, Mo, Se, Cr, Co – human enzymatic actions Fe, I, Zn – recommended daily allowances Cu, F – estimated safe ranges and adequate intake
Trace Elements: Modes of Action Act as catalysts either as Metallo-enzymes the trace element is an integral part of the enzyme molecule Fe, Zn, Mo Cu – firmly bound and incorporated in the protein molecule of the enzyme tyrosinase Metal-enzymes the metal ion is loosely associated with the enzymes Arginase Functions as constituents and activators of hormones Iodine: found in thyroid hormones Chromium: insulin activator Cobalt: acts as a structural center of vit.B12
Dietary Sources & Classification Good sources Meat Fish Natural plant foods Grains Beans Fruits Vegetables Consumption of processed foods REDUCES the intake of essential micronutrients, unless these foods are fortified to conc’ns at least equal to those naturally occurring in the product. 2 categories: 1. Those that have well-defined human requirements – Fe, Zn, I, Cu, F 2. Those that are integral constituents or activators of enzymes – Mn, Mo, Se, Cr, Co
Iron One of the most important minerals in nutrition Involved in oxygen transport and cellular respiration (in hemoglobin) Serves as an oxygen reserve in muscles metabolism (in myoglobin) Total quantity ofironin the body averages about 4g, consisting of two major fractions: 70% essential body iron hemoglobin, myoglobin, and intracellular enzymes such as cytochrome 30% mobilizable iron reserves ferritin&hemosiderin
Absorption Humans have difficulty in efficient iron absorption. Only 7-10% of iron in cereals and vegetables 10-30% in animal protein and soybeans Iron is absorbed in the reduced ferrous state (divalent) in the upper portion of the small intestine Ascorbic acid, citric acid, and amino acids convert the less absorbable ferric (trivalent) iron present in foodsmore phosphoric absorbable ferrous form If phytates (a salt of phosphoric acid ester) present in bran or food phosphates are ingested in excess, the absorption of iron can be impaired.
Absorption The Ferrous iron is initially taken up by the brush border of the intestinal wall, where it is passed into the intestinal mucosal cells. In the mucosal cells, it can be either bound to: Transferrin an iron-binding protein for transport of iron in blood And absorbed into the bloodstream or combined with another protein: Apoferritin This protein complex is known as ferritin (the storage form of iron), which remains within the cells and is released as needed. Control of iron absorption depends on the amount of iron deposited as ferritin in the mucosal cells
Absorption 2 most important factors determining the regulation of iron absorption: 1. The state of iron stores in the body 2. The state of RBC formation in the bone marrow Absorption is increased in conditions that decrease body iron during growth or pregnancy when new RBCs are being produced during anemia resulting from hemorrhage
Transport Transferrin special carrier protein in the plasma designed for binding and transporting iron. attach to the immature RBC and rapidly pass iron to them. attaches to the liver cells and more slowly transfers iron to them responsible for recycling iron and transporting it to the bone marrow by production of new RBCs The normal plasma iron concentration= 100 µg per 100 mL The total iron-binding capacity (TIBC) of transferrin = 330 µg/per 100 L
Transport A drop in the saturation of transferrin below 10-15% indicates iron deficiency anemia After 120 days, RBCs are destroyed by reticuloendothelial cells (large phagocytic cell) and the released iron is taken up by the transferrin molecules.
Iron and Storage Overload Ferritin storage form of excess iron in the liver cells as when it is deposited there among all cells of the body also found in the cells of spleen and bone marrow Hemosiderin an insoluble storage form of iron in the body as when the amount of of iron in the liver, spleen, and bone marrow EXCEEDS the capacity of the cells to form ferritin. Hemochromatosis occurs when there is excessive levels of hemosiderin or iron overload. characterized by excess deposition of iron in the tissues, especially in the liver, and by skin pigmentation
Iron and Storage Overload Common causes of Hemochromatosis: 1. Numerous transfusions in patients with hemolytic anemia (separation of hemoglobin from red blood cells) anemias 2. Excessive iron intake from food cooked in iron vessels 3. Drinking excessive amounts of cheap wines 4. Failure of the body to regulate absorption, as in alcoholics on low-protein diets and in patients with hereditary hemochromatosis
Recommended Dietary Allowances Iron intake usually tends to be inadequate in the infant and child during the first 2 years. The recommended dietary allowance (RDA)=10-15 mg/day Males 11-18 yrs. old: 18 mg daily 19 and older: 10 mg daily Females At childbearing age: 18 mg daily After menopause: 10 mg The amount of iron expected from a normal diet is about 6 mg/1000 kcal Only 10% of iron from is food is absorbed, as this approx. replaces the 1 mg/day lost physiologically in a normal adult
Food Sources 3 forms of iron in food 1. Heme 2. Nonheme 3. Additive iron Enriched white bread, rolls, and crackers are a major source of iron. The amount of iron to be absorbed from the food depends or on the bodily need for iron. The greater the need, the greater the absorption
Heme form of iron in hemoglobin and in myoglobin that is absorbed intact found in organ meats (liver, heart, kidney, spleen), red meats, veal, pork, poultry, fish, oysters, and clams, but not milk or milk products About 40% of iron in meat and fish is heme iron although only 1/3 can be absorbed by the body
Nonheme Accounts for the other 60% of iron in animal protein and all the iron in molasses, fruits (figs, dates), green veggies, dried beans, nuts, and grain products (wheat germ) Only 2-10% can be absorbed by the body
Additive iron found in both enriched and fortified products
Iron Deficiency Anemia Occurs due to inadequate intake or excessive loss of iron or both. Characterized by the production of small RBCs that are deficient in hemoglobin. The most common type of nutritional anemia It leads to loss of efficiency and impaired general health
Occurrences and Causes Occurs most frequently in infants and children due to undergoing rapid growth and having rapid RBC formation Occurs in pregnant women due to the increasing demand of the growing fetus on the mother’s body iron In adult males and postmenopausal women – pathological blood loss In premenopausal women – menstruational blood loss Bizarre food habits (avoidance of meat and vegetables) Inadequate intake among the elderly due to poverty
Clinical Manifestations Slow development; takes for months or years Anemia Characterized by weakness, fatigue, pallor, and numbness and tingling of the extremities Epithelial changes – early manifestations Nail changes; dullness, brittleness Fingernails may be flat instead of convex; spoon-shaped appearance with longitudinal ridges (koilonychia) Hair growth may be altered Dysphagia (difficulty in swallowing) in severe cases
Clinical manifestations: oral area Glossitis Inflammation of the tongue Fissures (clefts or grooves) at the corners of the mouth The papillae of tongue are atrophied, giving a smooth, shiny, red appearance to the tongue The clinical appearance of the tongue in iron deficiency resembles that in vit.B complex deficiency Oral mucous membranes may be atrophied and ashen gray More susceptible to carcinoma (cancer arising from epithelial cells) Plummer-Vinson syndrome Combination of dysphagia, koilonychia, angular stomatitis, and atrophic glossitis
THERAPY Administration of 200 mg of ferrous sulfate tablets 3x a day (after each meal) as prescribed by a physician Treatment should be continued for approximately 2 months after the hemoglobin level has returned to normal.
Zinc Approx. 2-3 g of zinc in human body Is concentrated in the eyes, liver, bones, prostate, prostatic secretions, and hair In blood, 85% in RBCs, but each WBC has about 25x than each RBC.
Functions An integral part of at least 70 enzymes that belong to metallo-enzymes Active component of carbonic anhydrase Essential for the transport of CO2 to the lungs Other enzymes with zinc content Alcohol dehydrogenase Lactate dehydrogenase Activates enzymes (carboxypeptidase and aminopeptidase) that function in the digestion of proteins Is part of alkaline phosphatase − bone metabolism Added to insulin to prolong the hypoglycemic effect It plays an essential role in RNA, DNA, and protein synthesis
Functions Essential for wound healing, tissue growth, and prevention of dwarfism, production of hormones. Zinc inadequacy may play an important role in the reduced immune response in protein-calorie malnutrition Used in the treatment of sickle-cell disease Assist in restoring a missing sense of taste in some cases Important for thymic hormone activity since its removal reduces hormone functions
Recommended Dietary Allowance RDI: 15 mg a day During pregnancy and lactation: 20-25 mg/day Infant at 6 mos. old: 3 mg/day 6 mos.-1 yr.: 5 mg/day 1-10 yrs.: 10 mg/day*These are relatively high values when considered in proportion to the amount of food eaten.
Food Sources Protein rich foods such as meat and fish Oysters and herring as highest zinc content per ounce Milk --- total dietary zinc intake**Grains contain dietary fiber and phytic acid, that can bind zinc, inhibiting its absorption, but when used in making bread with yeast, it inactivates the phytates and the body now obtains more of the zinc.
Deficiencies Causes Poor diet Excessive alcohol intake Liver disease Chronic kidney disease Genetic disorders Acrodermatitisenteropathica A sever gastrointestinal and cutaneous disease May intensify the anemia of sickle-cell disease
Deficiencies Clinical Manifestations Retardation of both growth and sexual development Poor appetite Slow healing of wounds Loss of sense of taste Progressive pustular dermatitis of the extremities, mouth, anus, and genital areas Emotional irritability Tremors Loss of coordination In pregnancy Abnormal taste sensations Prolonged gestation Protracted labor Increased risks to the fetus
Supplementation Consuming excessive amounts of zinc may increase the risk of cardiovascular disease due to: Low HDL High LDL Common zinc level in popular vitamin/mineral preparations is 15 mg (safe)
Clinical Application Zinc sulfate supplements can decrease wound healing time significantly Zinc peroxide powder when used topically on acute gingival lesions in acute necrotizing gingivitis, the soreness disappears soon enough and the mouth restores to its normal healthy condition
Selenium Essential component of the enzyme that catalyzes oxidation of glutathione which protects red blood cells through destruction of hydrogen peroxide protecting hemoglobin from oxidative damage Extremely effective in reducing the prevalence of keshan disease, which is characterized by abnormalities in the heart muscle. Estimated safe and recommended daily intake of selenium for adults is 0.05 to 0.2mg while for infants, children and adolescents is somewhat less.
Molybdenum Part of the molecular structure of two enzymes: Xanthineoxidase and Aldehydeoxidase, Xanthineoxidase is responsible for the conversion of xanthine to uric acid. Daily intake is 0.15 to 0.5mg
Chromium Trivalent chromium is the biologically active form of chromium Required for the maintenance of normal glucose and energy metabolism May act as cofactor in insulin and stimulates synthesis of fatty acids and cholesterol in the liver Daily intake is 0.05 to 0.2mg
Copper Functions :1. Aids in synthesis of hemoglobin in the bone marrow2. Form and maintain compounds having enzymatic activity3. Influence the central nervous system physiology4. Aids in formation of pigments5. Component of enzyme necessary for the oxidation of the amino acid tyrosine and vitamin C6. May also have a role in the maintenance of the myelin sheath around the nerve tissue
Copper Deficiency :1. Copper deficiency seen in australian lambs called “swayback disease” characterized by demyelination and degeneration of motor nerves in CNS, its prevented by giving copper supplements to ewes(female sheep) during pregnancy.2. Found by clinicians that combined administration of copper and iron is more effective in treating hypochromic anemia than the administration of iron alone
Copper Effects of excess : Accumulation of excess copper in body tissues, probably because of genetic absence of liver enzyme is called Wilson’s disease, characterized by neurological degeneration and cirrhotic liver changes. Reduction of dietary copper may be useful in treating this disease. Also be arrested by giving chelating agents like penicillamine to mobilize copper from tissues and promote excretion in the urine.
Copper Excess copper concentrations found in human saliva appear to inhibit acid production, although there is nothing conclusive to this theory. Daily intake is 2 to 3mg
Cobalt Part of the vitamin B₁₂ molecule May also be involved in the metabolism of sulfur containing amino acids Inadequacies of cobalt will cause anemia Essential for adequate nutrition of sheep and cattle, deficiency will cause extreme emaciation and wasting. High dose of cobalt stimulates the bone marrow to produce excessive numbers of red cells(polycythemia) and higher than normal hemoglobin level
Manganese Functions :1. needed for normal bone structure2. For reproduction3. Normal functioning of CNS4. Important catalyst and component of many enzymes in body, Enzymes involved in the synthesis of carbohydrates, those necessary for the protection of cells from high levels of oxygen and enzymes necessary for mucopolysaccharide synthesis
Manganese Effects of deficiency and excess :1. Manganese deficiency produces skeletal abnormalities in animals2. Excesses can produce profound neurological disturbances similar to those of Parkinson’s disease
Manganese Average adult estimated safe and adequate daily dietary intake appears to be between 2.5 to 5mg
Iodine One of the first trace elements recognized essential for normal health Integral part of the hormones thyroxine and triiodothyronine, functions to maintain the control of the energy metabolism of the body. Most important in synthesis of thyroid hormone is the ability of the thyroid gland to trap and oxidize iodine molecules into free iodine.
Hypothyroidism Goiter, Thyroid gland enlargement Develops swelling in the front of neck in the area of hyoid bone Iodine deficiency Potassium iodide in small doses may completely eliminate goiter Current level of enrichment furnishes 76 mg of iodine per g of salt
Hypothyroidism Cretinism and Myxedema are pathological conditions resulting from low thyroid activity Treatment is administration of thyroid hormone until euthyroid(normal) state is achieved If it affects a fetus prior to birth, cretinism develops
Hyperthyroidism Excessive activity of thyroid gland brought by deficiency of iodine producing an enlarged excretory gland as a result of hyperplasia of the cells lining the follicles along with increased colloidal material Produces hypermetabolic rate(increase pulse rate, temperature and blood pressure, extreme nervousness, irritability, increased sweating, dyspnea, weight loss and tiredness) Patients with diffuse primary thyroid hyperplasia may develop exopthalmos(abnormal protrusion of the eyeball)
Oral Effects of Imbalance In severe hypothyroidism, jaws are small and rate of tooth eruption is retarded Hyperthyroid patients conceivably develop caries rapidly due to their increased need for calories and possible use of excessive sugars
Mineral Elements That May Inhibitor Promote Caries 5 Categories of Elements accdg. to their Cariogenicity (by Navia) 1. Caries-promoting: Selenium, Magnesium, Cadmium, Platinum, Lead, Silicon 2. Mildly cariostatic: Molybdenum, Strontium, Calcium, Boron, Lithium, Gold 3. With doubtful effect on caries: Beryllium, Cobalt, Manganese, Tin, Zinc, Bromine, Iodine 4. Caries-inert: Barium, Aluminum, Nickel, Iron, Palladium, Titanium 5. Strongly cariostatic: Fluorine, Phosphorus
Possible Mechanism of TraceElements Action on Dental Caries By altering the resistance of the tooth by modifying the local environment at the plaque- tooth enamel interface By altering the size of enamel crystals available to acid exposure; influencing enamel solubility Smaller crystals have a greater surface area (more exposed to acid solubility) than larger crystals in enamel rods of similar size By influencing the microbial ecology of plaque to either inhibit or promote the growth of caries- producing bacteria