Medical & Clinical Reviews

Fluoride Fact on Human Health and Health Problems: A Review

Fluorine (F-) is a chemically reactive electronegative univalent gaseous halogen found in small amount in the water, air, plants and animals. Fluorine is essential for the maintenance and solidification of our bones and to prevent dental decay. It has beneficial effects on teeth and bones when it is present at low concentration in drinking water, but excessive exposure to fluoride in drinking-water, or in combination with exposure to fluoride from other sources, can give rise to a number of adverse effects which include teeth decay, osteoporosis and harm to kidney, bones, reproductive organs, nerve and muscle. Fluoride, when in excess, is known to interfere with thyroid gland function causing TSH elevation and lessen T3/T4 hormones in some populations which may be due to its antagonistic properties towards iodine. As an endocrine disruptor, F- induces more toxic outcome in diabetic patients. Chronic F- exposure through drinking water may leads to insulin resistance in humans in addition to its hyperglycemic effect due to increased hepatic glycogenolysis. Fluoride also hinders glycolysis by inhibiting enolase enzyme and repressed insulin secretion from islets of Langerhans cells resulting in elevation of blood glucose level.
High F- exposure is also associated with increased levels of FSH and LH, decreased estrogen and testosterone levels, disturbed androgen to estrogen ratios (A/E) and estrogen receptor to androgen receptor ratios (ER/AR). Decreased circulating testosterone concentrations were also reported in male skeletal fluorosis patients. The most significant consequences of fluoride exposures in male reproduction are: changes in the structure and functional activities of spermatozoa and disruption of spermatogenesis while in an experimental data involving female rats showed that high fluoride concentration lowers the pregnancy rate and the number of implantation. Most interestingly, recent research showed that exposure to high concentration of F- does have deleterious effect on the mental ability of children. A strong association between exposure to fluoride and low IQ was found and it was also noted that children who live in fluorosis prevalent areas have higher chances of developing a low IQ than those who live in normal areas. So it is clear that the severity of the above pathological conditions is dependent on the dose, duration and age of the individual. Therefore, to ensure whether people need any fluoride supplements or not, government should have to take initiative to prevent health problems due to deficiency or excess fluoride exposure. Evidence-wise further thorough research is essential based on scientific facts to enlighten best practices in the use of fluoride containing materials for the safety and security of public health.

Author(s):

Sananda Dey, Biplab Giri

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