Fluoride Information

Fluoride is the anion F, the reduced form of fluorine. Both organic and inorganic compounds containing the element fluorides. Fluoride, like other halides, is a monovalent ion (-1 charge). Its compounds often have properties that are distinct relative to other halides. Structurally, and to some extent chemically, the fluoride ion resembles the hydroxide ion. Fluorine-containing compounds range from potent toxins such as sarin to life-saving pharmaceuticals such as efavirenz, and from inert materials such as calcium fluoride to the highly reactive sulfur tetrafluoride. The range of fluorine-containing compounds is considerable as fluorine is capable of forming compounds with all the elements except helium and neon. Compounds containing fluoride anions and in many cases those containing covalent bonds to fluorine are called fluorides.

Positron emission tomography is commonly carried out using fluoride-containing pharmaceuticals such as fluorodeoxglucose, which is labeled with the radioactive isotope fluorine-18 that emits positrons when it decays into O.
Numerous drugs contain fluorine including antipsychotics such as fluphenazine, HIV protease inhibitors such as tipranavir, antibiotics such as ofloxacin and trovafloxacin, and anesthetics such as halothane. Fluorine is incorporated in the drug structures to reduce drug metabolism, as the strong C-F bond resists deactivation in the liver by cytochrome P450 oxidases.

Fluorine is the most electronegative element, distributed ubiquitously as fluorides in nature. Water is the major medium of fluoride intake by humans. Fluoride can rapidly cross the cell membrane and is distributed in skeletal and cardiac muscle, liver, skin, and erythrocytes. Fluorosis is a major public health problem resulting from long-term consumption of water with high fluoride levels. It is characterized by dental mottling and skeletal manifestations such as crippling deformities, osteoporosis, and osteosclerosis.


Fluoride has many applications in industry as well as in the body. Fluoride used for cavity prevention. Fluoride-containing compounds are used in topical and systemic fluoride therapy preventing tooth decay. They are used for water fluoridation and in many products associated with oral hygiene. Sodium fluoride was used to fluoridate water; however, hexaflurosilicic acid (H2SiF6) and its salt sodium Fluorosilicate (Na2SiF6) are more commonly used additives, especially in the United States. The fluoridation of water is use to prevent tooth decay and is considered by the U.S. Centers for Disease Control and Prevention as “one of the great public health achievements of the 20th century”. In some countries where large, centralized water is uncommon, fluoride is delivered to the populace by fluoridating table salt.

Soluble fluoride salts, of which NAF is the most common, are mildly toxic but have resulted in both accidental and suicidal deaths from acute poisoning. While the minimum fatal dose in humans is not known, a case of a fatal poisoning of an adult with 4 grams of NaF is documented. For Sodium Fluorosilicate(Na2SiF6), the 50% lethal dose (LD50) orally in rats is 0.125g/kg, corresponding to 12.5g for a 100kg adult. The fatal period ranges from 5 min to 12 hours. The mechanism of toxicity involves the combination of the fluoride, resulting in hypocalcaemia; calcium is indispensable for the function of the nervous system, and the condition can be fatal. Treatment involves oral administration of dilute calcium hydroxide or calcium chloride to prevent further absorption, and injection of calcium gluconate to increase the calcium levels in the blood. Hydrogen fluoride is more dangerous than salts such as NaF because it is corrosive and volatile, and can result in fatal exposure through inhalation or upon contact with the skin; calcium gluconate gel is the usual antidote.

Fluoridation of water is not without its problems, however. In higher doses used to treat osteoporosis, sodium fluoride can cause pain in the legs and incomplete stress fractures when the doses are too high; it also irritates the stomach, sometimes so severely as to cause ulcers. Slow-release and enteric-coated versions of sodium fluoride do not have gastric side effects in any significant way, and have milder and less frequent complications in the bones. I lower doses for water fluoridation, the only clear adverse effect is dental fluorosis, which can alter the appearance of children’s teeth during tooth development; this is mostly mild and is unlikely to represent any real effect on their appearance.

It is not known that such vital organs as the kidneys, thyroid, aorta, liver, lungs and others can be sites of an unusually high fluoride build-up. No matter how small the amount of fluoride in the diet, a part of it tends to accumulate e in the body. When the water supply is fluoridated the intake of the individuals considerably increased and the accumulation in the body increases. There is no clear cut pattern of retention for an individual. Fluoride can accumulate in the organs. Some individuals may store up to 100 times more fluoride in tissues than others.

Patients with reduce renal function, the potential for fluoride accumulation in the skeleton is increased. It has been known for many years that people with renal insufficiency have elevated plasma fluoride concentrations compared with normal healthy persons and are at a higher risk of developing skeletal fluorosis. (National Research Council, 2006, Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. National Academies Press, Washington D.C., pl140.

One study (Steyn and Jackson) found that since fluorine can rapidly cross the cell membrane and is distributed in skeletal and cardiac muscle, liver skin and erythrocytes that Fluorosis is a major public health concern. This is due to long term consumption of fluoridated water. They characterized it by dental mottling and skeletal manifestations such as crippling deformities, osteoporosis, and osteosclerosis. The study showed that fluoride toxicity affects children more severely and after shorter exposure to fluoride that adults, owing to the greater and faster accumulation of fluoride in the metabolically more active growing bones of children. These were found in deformities only related to children. None of the adults study has visible symptoms of skeletal toxic effects. However a few complained of back pain, and stiffness. Steyn and Jackson found out that 2.6 ppm fluoride in water caused deformities in children and referred to it as Kenhardt bone disease. Major skeletal manifestations observed in various studies of fluorosis are bowed legs (genu varum) or knock-knee (genu valgum), and stiffness of the cervical and lumbar spine. Their study also revealed fluorosis with crippling bone deformities.

Dr. Paul H Phillips, at the University of Wisconsin, Department of Biochemistry, found fluorine as a enzymatic inhibitor and that it interferes with metabolism of the breakdown of glucose. Dr Robert S, Harris, PH.D., Director of Nutritional Biochemistry Laboratories, Massachusetts Institute of Technology, states “There is plenty of evidence to indicate that fluorine in the amount of 1 ppm or slightly more interferes with enzyme systems and these enzymes systems are involved in the growth of bones, in the functioning of nerve tissue and so forth. A key finding came in 1981, when John Emsley showed that fluoride formed a strong hydrogen bond with the amide function. This gives a very plausible explanation as to why this ‘chemically inert’ entity fluoride could cause biochemical harm. Interference with the H-structure and function of proteins and nucleic acids is dependent on hydrogen bonds making and breaking. This potential disruption of H-bonds would explain fluoride’s inhibition of certain enzymes and possibly its interference.

Fluoride RDA

RDA values of Fuorides.
UL = 1.3 mg for children 1-3
10 mg for children >8 & adults

Food Sources

Tap water and food prepared with tap water contains fluoride. Natural sodium fluoride is found in the ocean, so most seafood contains it. Fluoride can also be found in gelatin and tea.

http://www.umm.edu/ency/article/002420fod.htm

Quiz

1. Fluoride is used in ________ to prevent tooth decay?
a. cereals and rice
b. milk and yogurt
c. toothpaste and mouth wash
2. Fluorine is part of which element group?
a. halogens
b. metals
c. noble gases
3. Fluouride deficiency symptoms in humans are:
a. death
b. inconclusive; not enough research
c. night blindness
4. Fluorosis occurs when the body has toxic levels of fluoride. The symptoms are:
a. changes in bone and kidneys
b. fatigue
c. hair loss
5. What toxicity disease can occur in children?
a. bone loss
b. difficulty walking
c. mottling of the teeth
6. Death can occur if 32-64 mg/kg of body of fluoride is ingested.
a. true
b. false




Answers:
1) c 2) a 3) b 4) a 5) c 6) a

Fluoride Toxicity

While fluoride deficiency diseases are not known, one can have toxic levels of the micromineral. Fluorosis is toxicity of fluoride and symptoms include changes in bones and kidneys. It may even cause changes in nerve and muscle function.
Mottling of the teeth can happen in children who have received 2-8 mg fluoride/kg of body weight on a regular basis.
Nausea, vomiting, diarrhea, acidosis and cardiac arrhythmias are cause by acute toxicity. Last but not least, death can occur if 32-64 mg/kg body weight is ingested.

Gropper, S. et al (2009). Advanced nutrition and human metabolism. Belmont: Wadsworth

Fluoride Deficiencies

Fluoride deficiency symptoms are still being researched. Studies with rats have shown stunted growth, infertility and anemia from a lack of fluoride but this has not been proven to be true of humans. However, a sufficient intake of fluoride helps prevent dental caries and maintians skeletal tissue.

Gropper, S. et al (2009). Advanced nutrition and human metabolism. Belmont: Wadsworth

Fluoride--What it is.

Fluoride is compound containing fluorine and another element. Fluorine is a very reactive (non-stabile) element. Fluorine combines readily with nearly all the other elements. This is due to it having only seven electrons in its outer shell. The element fluorine is represented by the symbol “F”. It has an atomic weight of 18.9 and an atomic number of 9. Fluoride is an anion of fluorine (F-) and most compounds that contain F- are called fluorides.

Diagram Group, Chemistry handbook, Revised edition, Facts on File, New York, 2006