National Academy of Sciences on Fluoride in Drinking Water
What is the National Academy of Sciences and why is its opinion
important?
The National Academy of Sciences (NAS) is one of four organizations that
comprise the National Academies*—the other three are
the National Academy of Engineering, the Institute of Medicine, and the National
Research Council (NRC). The National Academies perform an unparalleled public
service by bringing together committees of experts in all areas of scientific
and technological endeavor. These experts serve pro bono to advise the federal
government and the general public on scientific and technological issues that
affect people’s lives worldwide.
There have been several reports and booklets by the NAS and NRC with
references to water fluoridation.
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The 1951 NRC Fluoridation Report
NRC first reported on fluoride in drinking water November 29, 1951, and
found that fluoridation was safe and effective. It was recommended that any
communities with a child population of sufficient size, and that obtained
their water from sources free from or low in fluoride, should consider
adjusting the concentration to optimum levels for oral health. This report
is not available through the NRC at this time, although copies may be in
libraries. A summary and presentation of the findings of the original report
was published in the January 1952 edition of Journal American Water Works
Association Vol 44, no. 1, p1-8, January, 1952. National Research
Council Fluoridation Report, Kenneth F. Maxcy, J. L. T Amleton, Basil G.
Bibby, H. Trendley Dean, A. McGehee Harvey, Francis F. Heyroth. Journal of
Public Health Dentistry, Volume 12, Issue 1, Pages 24—33,
1952 by the American Association of Public Health Dentistry.
In this 1977 report, the NRC included ingestion of fluoride in drinking
water as part of its evaluation to support the U.S. Environmental Protection
Agency (EPA) in the effort to comply with the 1974 Safe Drinking Water Act
on the scientific basis for the Interim Primary Drinking Water Regulations
that were promulgated as part of the Act. This scientific study specifically
considered potential adverse health effects of substances in drinking water.
The central effort of the study was an assessment of the long-term
biological effects of ingesting the variety of different substances present
in trace amounts in drinking water. The volume included an extensive
analysis on fluoride ingestion and concluded that “there is no generally
accepted evidence that anyone has been harmed by drinking water with
fluoride concentrations considered optimal.” Only two adverse affects were
identified including enamel fluorosis and skeletal fluorosis“ occurring when
fluoride is at levels in excess of the concentrations recommended for good
oral health.” This report can be purchased from the National Academy of
Sciences and is identified as Library of Congress Catalog 77—089284
or International Standard Book Number 0-309-02619—9.
In 1993, the NRC concluded that the EPA maximum contaminant level of 4
mg/L in drinking water was an appropriate standard and was safe for
ingestion at levels considered optimal for oral health. The report also
identified additional studies to address fluoride intake, dental fluorosis,
bone strength, and carcinogenicity.
In 2006, the NRC stated in this report that in developing regulatory
standards for high levels of fluoride in drinking water, three adverse
health effects warranted consideration: severe enamel fluorosis from
exposure to these high levels between birth and 8 years of age, risk of bone
fractures, and severe forms of skeletal fluorosis after lifetime exposure (a
rare condition in the United States).
The NRC recommended that the EPA assess if 4 mg/L provided sufficient
protection from these health conditions. A
CDC
Statement on the 2006 NRC Report has more information on this report.
See the Frequently Asked Questions for further information about the
responsibilities of the EPA for setting standards for fluoride in water.
In this report, the NRC considered research issues related to the medical
geology field on connections between earth science and public health, addressing
both positive and negative societal impacts. This report identified fluoride as
a mineral that can positively influence human health, and although earlier NRC
reports were not conclusive in their opinions, this report concluded that
fluoride was considered to be an element essential for human life based on its
role in cellular functions involving metabolic or biochemical processes. The
report further stated that fluoride in drinking water has two beneficial
effects: preventing dental caries and contributing to bone mineralization and
bone matrix integrity.
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The 2008 NAS Spotlight on Water Fluoridation
In the NAS booklet
“Drinking Water: Understanding the Science and Policy behind
a Critical Resource,” * the NAS spotlighted fluoride in drinking water and stated:
In places where fluoride is artificially added to water, the fluoride
concentration is kept at a safe level between 0.7 and 1.2 mg/L.
Does CDC consider the opinion of the NRC on fluoride in drinking water in its
own recommendation on community water fluoridation?
Yes, CDC considers comprehensive reviews by the NRC and other systematic
scientific studies in its recommendation that community water fluoridation is a
safe, effective, and inexpensive method to reduce tooth decay (dental caries)
among populations living in areas with adequate community water supply systems.
The findings of the NRC reports have been consistent with CDC’s assessment that
water is safe at the levels used for water fluoridation (0.7–1.2 mg/L). Water
fluoridation should be continued in communities currently fluoridating and
extended to those without fluoridation.
* Links to non-Federal organizations are
provided solely as a service to our users. Links do not constitute an
endorsement of any organization by CDC or the Federal Government, and none
should be inferred. The CDC is not responsible for the content of the individual
organization Web pages found at this link.
Date last reviewed: October 9, 2009
Date last modified: October 9, 2009
Content source:
Division of Oral Health, National Center for Chronic Disease Prevention and
Health Promotion |
