Transcript
TRACE MINERALS OTHER THAN FLUORIDES
DBACoojacinto
LianzaMicu
Essential Trace Minerals
Essential Trace Minerals Trace elements or micro-minerals Inorganic nutrients required by humans in
very small amounts from 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,
F2. Those that are integral constituents or activators of enzymes –
Mn, Mo, Se, Cr, Co
Iron
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 of iron in 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
Physiological Functions
AbsorptionTransport
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 foods more 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 body2. 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 wines4. 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. Heme2. Nonheme3. 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 Vomiting, diarrhea, and intestinal hypermotility
increases iron loss.
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
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
Acrodermatitis enteropathica 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
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
Molybdenum Part of the molecular structure of two
enzymes: Xanthine oxidase and Aldehyde oxidase, Xanthine oxidase is responsible for the conversion of xanthine to uric acid.
Daily intake is 0.15 to 0.5mg
CHROMIUM
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
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 C
6. 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
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
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
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.
Effects of Imbalance
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
Effects on development of dental caries
Mineral Elements That May Inhibit or 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 Trace Elements 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