Fluoride is found naturally in soil, water, foods, and several minerals, such as fluorapatite and fluorite.
Fluoride concentration in seawater averages 1.3 ppm (parts per million), while in fresh water supplies the natural range is typically between 0.01 to 0.3 ppm.
Fluoride is also synthesized in laboratories. Synthesized fluoride is commonly added to drinking water, toothpaste, mouthwashes and various chemical products.
Fluoride is a naturally occurring mineral found in water in varying amounts, depending on which area of the UK you live in.
Functions:
Fluoride is said to protect the teeth in two ways:Protection from demineralization - when bacteria in the mouth combine with sugars they produce acid. This acid can erode tooth enamel and damage our teeth. Fluoride can protect teeth from demineralization that is caused by the acid.
Remineralization - if there is already some damage to teeth caused by acid, fluoride accumulates in the demineralized areas and begins strengthening the enamel, a process called remineralization.
Fluoridation
Most water supplies contain some fluoride and around half a million people in the UK receive naturally fluoridated water.
Another 5.5 million people receive water that has had the fluoride concentration raised to around one part per million (1ppm). This level of fluoridation has been shown to have the most benefit for reducing decay levels.
The maximum amount of fluoride permitted in drinking water is 1.5 mg/l (milligrammes per litre).
What food fluoride is found in:
Food/Drink Fluoride (mg per 100g) Portion Fluoride (mg per portion)
Black Tea (brewed) 0.373 1 cup, 240g 0.884
Raisins, seedless 0.234 small box, 43g 0.033
Table wine 0.153 Bottle, 750ml 1.150
Municipal tap-water, (Fluoridated) 0.081 Recommended daily intake, 3 litres 2.433
Baked potatoes, Russet 0.045 Medium potato, 140g 0.078
Lamb 0.032 Chop, 170g 0.054
Carrots 0.003 1 large carrot, 72g 0.002
Other food sources of fluoride include, seafood, buckwheat, coffee, fish, lettuce, onion, rice, soybean, spinach and gelatin as well.
What symptoms and disorders deficiency may cause?
Fluoride or fluorine deficiency is a disorder which may cause increased dental caries, weak bones and teeth and possibly osteoporosis due to a lack of fluoride in the diet.
Problems related to excessive doses:
Soluble fluoride salts, of which sodium fluoride is the most common, are only mildly toxic, although they have resulted in both accidental and suicidal deaths from acute poisoning. The lethal dose for most adult humans is estimated at 5 to 10 g (which is equivalent to 32 to 64 mg/kg elemental fluoride/kg body weight).
However, a case of a fatal poisoning of an adult with 4 grams of sodium fluoride is documented,(*) while a dose of 120 g sodium fluoride has been survived.(#) For Sodium fluorosilicate (Na2SiF6), the median lethal dose (LD50) orally in rats is 0.125 g/kg, corresponding to 12.5 g for a 100 kg adult.
* Rabinowitch, IM (1945). "Acute Fluoride Poisoning". Canadian Medical Association journal US National Library Of Medicine, US National Institutes Of Health
# Abukurah AR, Moser AM Jr, Baird CL, Randall RE Jr, Setter JG, Blanke RV (1972)."Acute sodium fluoride poisoning" The Journal Of The American Medical Association.
The fatal period ranges from 5 min to 12 hours. The mechanism of toxicity involves the combination of the fluoride anion with the calcium ions in the blood to form insoluble calcium fluoride, resulting in hypocalcemia; calcium is indispensable for the function of the nervous system, and the condition can be fatal.
Treatment may involve 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.
In the 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.
In the lower doses used 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 aesthetic appearance or on public health.
Fluoride was known to enhance the measurement of bone mineral density at the lumbar spine, but it was not effective for vertebral fractures and provoked more non vertebral fractures.
In areas that have naturally occurring high levels of fluoride in groundwater both dental and skeletal fluorosis can be prevalent and severe.
Topical
Concentrated fluoride solutions are corrosive. Gloves made of nitrile rubber are worn when handling fluoride compounds. The hazards of solutions of fluoride salts depend on the concentration. In the presence of strong acids, fluoride salts release hydrogen fluoride, which is highly corrosive.Reccomended doses per people in the UK:
Recommended Dietary AllowanceRDA for adults: 1.5 - 4.0 mg
RDA for child/adolescent: 1.5 - 4.0 mg
RDA for age 0-1: 0.1 - 1.0 mg
RDA for age 1-3: 0.5 - 1.5 mg
The maximum safe daily consumption of fluoride is 10mg for an adult.
The above is 1980 values for RDA.
For over thirty years, Recommended Daily Amounts has existed in the United Kingdom. It has been used to measure the adequacy of an individual's diet. However, in 1991 the Committee on Medical Aspects of Food Policy (COMA) gave forth a whole new set of figures upon the request of the Department of Health's Chief Medical Officer. Reference Nutrient Intake (RNI) is one of these sets collectively known as "Dietary Reference Values." RNI is an amount of a nutrient that is enough for almost every individuals, even someone who has high needs for the nutrient. This level of intake is, therefore, considerably higher than what most people would need. If individuals are consuming the RNI of a nutrient they are most unlikely to be deficient in that nutrient.
The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods from the food guide plate.