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Fluoride, Fluorine, F, F-, Fluo

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Fluorine is widely but unevenly distributed in nature. Although fluoride is not considered an essential nutrient it has a very important role in bone and teeth and therefore is considered to be beneficial to humans. Fluoride is found in bones, teeth, thyroid and skin. The average adult body contains approximately 2.6 g of fluoride.

Physiological role of fluoride

Strengthen tooth enamel: Protects teeth from damage by creating compounds with calcium and phosphorus, which are stronger and less soluble than other calcium salts. These compounds remain in the bones and are hardly absorbed into the circulation in case of need for calcium. Children whose mothers during pregnancy consume enough fluoride have less damage to the teeth than children whose mothers had not consumed enough of this nutrient.

Bones are more stable and resistant to degradation if the food has a sufficient amount of fluoride.


The absorption of fluorine is almost complete. Its retention is 57.6% of that absorbed as against 43.9% of that absorbed in the rats placed on diet deficient in Ca and P. Its distribution and deposition is mainly in the calcified structures, soft tissues containing only a very small fraction of fluorine retained in the system. Among the soft tissues, the skin together with hair contains the highest amounts of fluorine; brain, heart, small intestine, kidney, liver and adrenals come next in the order. Among the calcified structures, humerus contains the highest amount of fluorine, and vertebrae and epiphyses come next in order. After the further administration of fluorine is discontinued, the elimination of fluorine from the system, in a period of 12 weeks, is 33.74% of that deposited, and is mainly through the urinary system. In terms of percents, the elimination of fluorine is greater from the soft tissues than from the blood and calcified structures, and from amongst the calcified structures, it is highest from the incisors, and then, in descending order, from epiphyses, scapula, ribs and other bones. Fluoride is excreted through the kidneys.

Food sources of fluoride

Natural sources of fluoride are tea, meat, fish, cereals and fruit. But fluoride content in these foods depends primarily on the areas of their origin, and how much fluoride is in the soil in which to grow. Drinking water contains significant amounts of fluoride. A certain amount of ingested fluorine is by toothpaste.

Fluoride content in food products


µper 100 g of food













Potatoes, mashed




Peas, cooked


Meat – veal


Meat – pork


Fish – baked


In developed countries, fluoride is added to drinking water at a concentration of 1 ppm (parts per million). In this way its intake is about 1-2 mg of fluoride per day.

Recommended daily allowance

Data for the daily recommended amounts of fluoride were given in 1997. in the United States. The basis for the calculation of these values is taken from the amount of fluoride that prevents the formation of tooth decay and does not cause fluorosis.

The recommended and maximum daily intake of fluoride


Recommended daily amount (mg)

Maximum daily amount (mg)







Baby (6-12 months)



Children (4-8 years)



Children (9-13 years)



In developed countries, fluoride is added to drinking water at a concentration of 1 ppm (parts per million). In this way its intake is about 1-2 mg of fluoride per day.

Fluoride deficiency

Deficient amounts of fluoride in the body leads to the appearance of children dental caries, while in adults most likely to osteoporosis. The lack of fluoride in the body occurs primarily in areas where water is not fluoridated.


Signs of excess fluoride in the body are dermatitis, spots on teeth as the enamel gets yellow-brown color. This disease is known as enamel fluorosis. If somebody assimilate large amounts of fluoride (20-80 mg per day) over a longer period of time it can also a bone fluorosis occur. In this case decreases appetite, joints become stiff and painful. Spinal bones, pelvis and vertebrae become more intense, so the calcium deposits in muscles and tendons. Fatal fluoride poisoning is possible only when the amount of fluoride that is ingested is 2500 times more than the recommended daily amount.

There is some evidence that fluoride in the water is associated with the appearance of several types of cancer (particularly cancer of the uterus), although it is not yet fully proven.

Nowadays, water is more and more fluoridated, which contributes to reduced caries, but can lead to the occurrence of dental fluorosis in which teeth become scrawled with yellow and brown spots. It can also occur dermatitis in more sensitive person.

Fluoride in medicine

Fluoride is used for the treatment of dental caries. It is component of toothpaste, tablets, gels, mouthwashes. Fluoride reduces the loss of minerals from the teeth and protects them against bacteria that produce acid in the mouth.

Sodium fluoride in combination with calcium is used to treat osteoporosis because fluoride increases bone density. In addition, fluoride is used in the treatment of rheumatoid arthritis.

When injuries and after surgery fluoride is used for faster healing of wounds due to its antibacterial activity. It is also used to treat bone pain, prevention of hearing loss in patients with otosclerosis.


Cerklewski F.L., 1998, “Fluoride--essential or just beneficial,” Nutrition (Burbank, Los Angeles County, Calif.) 14(5): 475-476. [Web Reference]

Malhotra V.K., 2011, “Biochemistry for students,” 12th Edition. JP Medical Ltd, New Delhi, India. [Web Reference]

Soetan K.O., Olaiya C. O. and Oyewole O.E., 2010, “The importance of mineral elements for humans, domestic animals and plants-A review,” African Journal of Food Science; 4(5): 200-222. [Web Reference]

Wadhwani T.K., 2013, “METABOLISM OF FLUORINE: Absorption, Retention, Distribution and Elimination of Fluorine, and Its Effect on the Vitamin C Content of Different Tissues, and on the Iodine Content of Thyroids of Rats and Monkeys,” Journal of the Indian Institute of Science; 35(4): 354-362. [Web Reference]

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