MINERALS

Damion Francis MSc.

TMRI-ERU

Phosphorus

• 85% of phosphorus is located in bones and teeth

• Remainder found in muscles, organs, blood, and other fluids

• The mineral exist as an ion or in bound form such as with phosphoprotein and phospholipids

• majority of the phosphorus in the body is found as phosphate (PO4)

Functions

• structural component of bone in the form of a calcium phosphate salt called hydroxyapatite

• components of cell membranes (phospholipids)

• All energy production and storage are dependent on phosphorylated compounds (ATP)

• maintain normal acid-base balance (pH)

Functions

• storage and transmission of genetic information, in DNA and RNA

Metabolism

• Dietary phosphorus is readily absorbed in the small intestine

• Excess is excreted by the kidney• Regulation of blood calcium and

phosphorus levels is interrelated through the actions of parathyroid hormone (PTH) and vitamin D

• PTH increases urinary excretion of phosphorus to balance calcium levels

Requirements

• RDA for phosphorus was based on the maintenance of normal serum phosphate levels in adults

• This represent adequate phosphorus intake to meet cellular and bone formation needs

• Requirement range from 700 – 1250 mg/day

Sources

• Phosphorus is found in most foods • Dairy products, meat, and fish are good

sources• phosphorus in all plant seeds (beans, peas,

cereals, and nuts) is present in a storage form of phosphate called phytic acid or phytate

• Only about 50% of the phosphorus from phytate is available to humans because we lack the enzyme(phytases) that liberate it from phytate

Toxicity• The most serious adverse effect of abnormally

elevated blood levels of phosphate (hyperphosphatemia) is the calcification of non-skeletal tissues, most commonly the kidneys

Deficiency• The effects of hypophosphatemia may include

loss of appetite, anemia, muscle weakness, bone pain, rickets (in children), osteomalacia (in adults), increased susceptibility to infection, numbness and tingling of the extremities, and difficulty walking

Oral Implications

• Phosphorus deficiency has been associated with incomplete calcification of teeth

• Increased caries susceptibility during development

• Increased vulnerability to periodontal disease via effect on alveolar bone

Magnesium

• Magnesium plays important roles in the structure and the function of the human body

• The adult human body contains about 25 grams of magnesium.

• Over 60% of all the magnesium in the body is found in the skeleton, about 27% is found in muscle, while 6 to 7% is found in other cells, and less than 1% is found outside of cells

Function

• Activates more than 300 enzymes (energy related)

• Regulates (Ca, K, and Na) transmission of nerve impulses. Calcium contract muscles and magnesium relax muscles

• Ensures proper DNA and RNA formation and function

• Facilitates PTH secretion

Metabolism

• Healthy individuals absorbs 40-60% magnesium consumed

• Absorption enhanced by calcium, phosphorus and fat

• Longterm storage in the bones• Kidney is the organ regulate magnesium

homeostasis • 90% of filtered magnesium is reabsorbed

by the kidneys in response to salt and H20 reabsorption

Interactions• High doses of zinc in supplement form appear to

interfere with the absorption of magnesium • Calcitriol may increase the intestinal absorption of

magnesium to a small extent• However, magnesium absorption does not seem to

be calcitriol-dependent as is the absorption of calcium and phosphate.

• High calcium intake has not been found to affect magnesium balance in most studies. Inadequate blood magnesium levels are known to result in low blood calcium levels, resistance to PTH, and resistance to some of the effects of vitamin D

Oral Implications

• Magnesium deficiency related to increased fragility of the alveolar bone

• Increase propensity for gingival hypertrophy

Food Sources

• Magnesium is widely distributed in foods

• Most commonly found in plants containing chlorophyll (dark green leafy vegetables)

• Whole grains and nuts are also a rich source

• Animal products are lower in magnesium 

Fluoride

• Fluorine occurs naturally in the Earth's crust, water, and food as the negatively charged ion, fluoride (F-)

• Fluoride is considered a trace element because the daily requirement for maintaining dental health is only a few milligrams a day.

• About 95% of the total body fluoride is found in bones and teeth

Fluoride

• its role in the prevention of dental caries (tooth decay) is well established

• fluoride is not generally considered an essential mineral element because humans do not require it for growth or to sustain life

• However, if one considers the prevention of chronic disease (dental caries), an important criterion in determining essentiality, then fluoride might well be considered an essential trace element

Function

• Fluoride is absorbed in the stomach and small intestine

• Once in the blood stream it rapidly enters mineralized tissue (bones and developing teeth)

• At usual intake levels, fluoride does not accumulate in soft tissue.

• The predominant mineral elements in bone are crystals of calcium and phosphate (hydroxyapatite)

• Fluoride's high chemical reactivity and small radius allow it to either displace the larger hydroxyl (-OH) ion in the hydroxyapatite crystal, forming fluoroapatite, or to increase crystal density by entering spaces within the hydroxyapatite crystal.

• Fluoroapatite hardens tooth enamel and stabilizes bone mineral

Mechanism of action on Teeth

Preeruptive Sytemic Effects– Fluoride is incorporated into developing

tooth’s mineralized structure– Fluoride being more reactive exchange

with hydroxyl (OH) group in hydroxyapatite (Ca10[PO4]6[OH]2) to form fluoroapatite (Ca10[PO4]6F2) or a mixed fluorohydroxyapatite (Ca10[PO4]6FOH)

– The fluoride ion makes apatite crystals less soluble and more resistant

Mechanism of action on Teeth

• Presence of fluoride in dental enamel increase resistance to demineralization after eruption

• Systemic fluoride during tooth formation is no longer believed to provide the most important benefit I preventing dental caries

Mechanism of action on Teeth

Posteruptive Effects– Benefits of fluoride occurs primarily in fluid

phase at the tooth surface– Fluoride decreases demineraization when

tooth is exposed to organic acids and for increasing remineralization rate

– Interference in the formation and function of dental plaque microorganism

– Increase rate of posteruptive maturation– Improve tooth morphology (preeruptive)

Nutrient Interactions

• Calcium and magnesium form insoluble complexes with fluoride decreasing fluoride absorption when present in the same meal

• Absorption of fluoride in the form of monofluorophosphate (unlike sodium fluoride) is unaffected by calcium

• diet low in chloride (salt) has been found to increase fluoride retention by reducing urinary excretion of fluoride

Requirements

• The Food and Nutrition Board (FNB) of the Institute of Medicine recommendations for fluoride intake in 1997

• inadequate data to set a RDA, instead Adequate Intake levels were based on estimated intakes (0.05 mg/kg of body weight)

• shown to reduce the occurrence of dental caries most effectively without causing the unwanted side effect of tooth enamel mottling known as dental fluorosis

Sources

• The fluoride content of most foods is low (less than 0.05 mg/100 grams)

• Rich sources of fluoride include tea, which concentrates fluoride in its leaves, and marine fish that are consumed with their bones (e.g., sardines)

• Foods made with mechanically separated (boned) chicken, such as canned meats, hot dogs, and infant foods also add fluoride to the diet

• Foods generally contribute only 0.3-0.6 mg of the daily intake of fluoride