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OneStop Data Fluoride: Health Information Summary
What's New? Fluoride is widely found in water supplies, but usually below a concentration
Sign up for a -news that would cause undesirable effects. The Fluoride content of groundwater
generally averages around 0.4 parts per million (ppm) nation -wide. The
concentration of Fluoride in natural waters depends primarily on the
A -Z Topics List solubility of the fluoride contained in the rocks with which the water is in
contact. Estimates made in the early 1990s indicated that about 1.6 million
people have Fluoride in their drinking water that exceeds the drinking water
guideline (a Secondary Maximum Contaminant Level or SMCL) established
to keep the occurrence and severity of dental fiuorosis very low.
Fluoride is present to some extent in nearly all foods. However, some foods
may make significant contributions to overall Fluoride intake. These include
some seafood, especially those that are often consumed with the bones
such as sardines, products made from bone such as gelatin, and non - herbal
teas. Commercial foods processed with Fluoridated water or beverages
made from Fluoridated water may be additional hidden sources of Fluoride.
Most toothpaste sold today contains Fluoride at 900 to 1,100 ppm.
Industrial exposure to Fluoride in dusts and gases may occur most notably
in processes such as grinding of Fluoride- containing minerals, smelting, kiln
firing of brick and other clay products, combustion of coal and in the
aluminum and steel industries. However, the contribution of fluoride air
pollution to most people's Fluoride exposure is considered to be negligible.
Health Effects
Absorption
Fluoride can be absorbed from the gastrointestinal tract after Ingestion,
following inhalation, and through the skin. Soluble forms of Fluoride, such as
those added to Fluoridate water, have been found to be absorbed at an
efficiency of 90 percent or greater. Of the Ingested Fluoride that remains in
the body, 99 percent is incorporated into the bones and teeth.
Beneficial Health Effects
Fluoride is an essential nutrient for the proper development of teeth and
bones. Fluoride prevents tooth decay by Inhibiting the production of acid by
decay- causing bacteria and enhancing the remineralization of enamel that
has been attacked. Fluoride also becomes Incorporated into teeth, making
them more decay resistant.
For approximately 60 years, Fluoride has been added to drinking water in
small amounts for prevention of dental caries (cavities). The usual dosage
of added Fluoride is in the range of 0.7 to 1.2 milligrams per liter (mg /liter);
http: / /www. des. state. nh. us /factsheets /ehp /ard- ehp- 14.htm 1/8/2008
Skeletal fluorosls results from chronic exposure to Fluoride at levels greater
than 4 ppm in drinking water. In its mildest form, it Is characterized by a
slight increase in bone density. In Its most severe form, skeletal Fluorosis is
characterized by Irregular bone deposits that may cause crippling arthritis
when occurring in joints. Skeletal Fluorosis is extremely rare in the US, but
it is a public health problem in some countries.
Reproductive /Developmental Effects
The results of animal studies indicate that reproductive or developmental
effects occur at high concentrations that humans would seldom encounter.
Fluoride does transfer through the placenta to the fetus. Only a small
amount of Fluoride passes Into breast milk. A few human studies have found
an association between high Fluoride levels and decreasing IQ scores.
However, these studies did not control for other important factors
influencing IQ such as nutrition and exposure to other chemicals. Some
studies have suggested that there is a link between high fluoride exposure
in drinking water and increases in Down Syndrome, but the studies have
limitations, which reduce their usefulness for prediction.
Carcinogenic Effects (ability to cause cancer)
Population based human studies, for the most part, have been unable to
detect any increases in cancer rates in areas that had fluoride added to their
drinking water supplies when compared with areas with no added fluoride. A
few investigations have detected positive associations between fluoride
exposure in drinking water and a rare type of.bone cancer called
osteosarcoma. The association was found in young males. However, the
osteosarcomas did not appear to be related to either the introduction of
fluoride or the duration of fluoridation. Consequently, it was concluded that
the incidence of this bone cancer was not due to fluoride exposure.
Osteosarcoma in youths is the focus of fluoride cancer studies because most
fluoride is deposited in bone, high doses have been found to stimulate cell
division in osteoblasts, where new bone cells are formed, and, in humans,
bone growth occurs in childhood and adolescence. As with other rare
diseases, it is difficult for a study to be able to detect small increases of a
disease in a population if it is occurring.
Animal studies have also been conducted investigating the potential for
fluoride to cause cancer. The older studies do not Indicate an association
between fluoride and cancer, although these studies were somewhat
limited. A study conducted by the National Toxicology Program (NTP)
examining the effects of lifetime fluoride ingestion found a slight increase in
bone cancer in male rats, although there was no evidence of increased
cancer in female rats or mice of both sexes. The NTP concluded that there
was "equivocal evidence" of carcinogenicity from this study indicating that
an association between fluoride exposure and bone cancer was positive, but
weak.
Another animal study found no evidence that fluoride exposure is associated
with cancer, although mice were found to have increases in noncancerous
bone tumors. In the most recent review of fluoride toxicology, the NAS
Committee concluded that the conflicting evidence of some weakly positive
associations between fluoride exposure and bone cancer and the negative
evidence for an association requires additional studies to clarify this issue.
One such study in humans is in progress, with results expected in 2006.
Health Standards and Criteria
The EPA has established a Maximum Contaminant Level Goal (MCLG) for
fluoride In public drinking water systems. MCI-Gs are nonenforceable health
http: / /www. des. state. nh. us /factsheets/ehp /ard- ehp- 14.htm 1/8/2008
WATER FLUORIDATION NOTICE
OMIMIIaRI r
The California Department of Public Health (CDPH) recommends suspending prescription fluoride
supplements for one year in areas served by the Metropolitan Water District of Southern California.
Back -round
Pursuant to Title 22, Section 64433.7 of the California Code of Regulations, this letter serves as official notice
that the Metropolitan Water District of Southern Califomia (MWD) will begin to increase the fluoride content of
the treated water it supplies to its member agencies within Los Angeles, Orange, Riverside, San Diego, and
Ventura counties. The fluoride level in the water supplied from all five MWD treatment plants will be increased
from the current levels of 0.1 - 0.4 ppm (mglL) to 0.7 - 0.8 ppm starting October 29, 2007. By adjusting the
fluoride content of MWD's treated water supply, the MWD will supply its member agencies with water that
contains the optimal level of fluoride. This important preventive public health measure will help reduce the
incidence of dental caries (tooth decay) for residents of all ages in our community.
Local Public Water Systems
Local public water systems that use exclusively MWD water will be receiving, and thus delivering, optimally
fluoridated water to their customers. However, the MWD service delivery area is vast and some systems blend
MWD water with their own local water sources before it is supplied to customers. This may result in the blended
water having suboptimal fluoride levels ( <0.6 ppm). While suboptimal fluoridation still provides some benefit,
the CDPH has requested local public water systems use a one -year period to determine the average fluoride
level of the blended water supplied to customers.
Prescription Fluoride Supplements
Prescribing fluoride supplements is at the professional discretion of health providers based on factors such as
the current level of fluoride in the local public water system as well as a patient's overall risk for dental disease.
However, it is recommended that physicians and dentists suspend supplements for one year after the MWD
implementation date in order to allow the local public water systems mentioned above time to record average
fluoride levels in their water. Halting supplements during this one -year period will help ensure that consumers do
not receive more fluoride than is necessary and will not affect tooth formation in children. After one year
(October 29, 2008) and thereafter, we recommend providers resume verifying the fluoride level of local public
water system using the CDPH website listed below. This will help guide physicians and dentists in providing
updated fluoride supplement prescriptions to patients. If the average fluoride level of a local public water system
is 0.6 ppm or greater, the CDPH and U.S. Centers for Disease Control & Prevention suggest you discontinue
fluoride supplements for your patients.
To review fluoride levels in California public water systems, refer to the section entitled
"Fluoride Levels in Public Water Systems"
on the CDPH website at:
www.cdph.ca.gov/certlic/drinkingwater/Pages/Fluoridation.aspx