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Apr 2000: Dr. Hardy
Limeback, BSc, PhD, DDS
Hardy Limeback
Dr. Hardy Limeback, BSc, PhD, DDS
Associate Professor and Head, Preventive Dentistry
124 Edward St., Toronto, Ontario, M5G-1G6
Fax (416) 979-4936
Tel(416) 979-4929
E-mail: hardy.limeback@utoronto.ca
April, 2000
To whom it may concern:
Why
I am now officially opposed to adding fluoride to drinking water
Since April of 1999, I have publicly decried the addition of fluoride,
especially hydrofluosilicic acid, to drinking water for the purpose of
preventing tooth decay. The following summarize my reasons.
New
evidence for lack of effectiveness of fluoridation in modern times.
1.
Modern studies (published in the 1980's 1990's) show dental decay rates are
so low in North America that the effects of water fluoridation cannot be
measured. Because of the low prevalence of dental decay, water fluoridation
studies today must be carefully conducted to correct for mobility of
subjects between fluoridated and non-fluoridated areas, access to fluoride
from other sources, the lack of blinding and problems with the `halo'
effect. Even when very large sample sizes are used to obtain statistically
significant results, the benefit of water fluoridation is not a clinically
relevant one (the number of tooth surfaces saved from dental decay per
person is less than one half). Recent studies show that halting fluoridation
will either result in only a marginal increase in dental decay which cannot
be detected or no increase in dental decay at all.
2.
The major reasons for the general decline of tooth decay worldwide, both in
non-fluoridated and fluoridated areas, is the widespread use of fluoridated
toothpaste, improved diets, and overall improved general and dental health
(antibiotics, preservatives, hygiene etc).
3.
There is now a better understanding of how fluoride prevents dental decay.
What little benefit fluoridated water may still provide is derived primarily
through topical means (after the teeth erupt and come in contact with
fluorides in the oral cavity). Fluoride does not need to be swallowed to be
effective. It is not an essential nutrient. Nor should it be considered a
desirable `supplement' for children living in non-fluoridated areas.
Fluoride ingestion delays tooth eruption and this may account for some of
the differences seen in the past between fluoridated and non-fluoridated
areas (i.e. dental decay is simply postponed). No fluoridation study has
ever separated out the systemic effects of fluoride. Even if there were a
systemic benefit from ingestion of fluoride, it would be miniscule and
clinically irrelevant. The notion that systemic fluorides are needed in
non-fluoridated areas is an outdated one that should be abandoned
altogether.
New evidence for potential serious harm from long-term fluoride ingestion.
1.
Hydrofluorosilicic acid is recovered from the smokestack scrubbers during
the production of phosphate fertilizer and sold to most of the major cities
in North America, which use this industrial grade source of fluoride to
fluoridate drinking water, rather than the more expensive pharmaceutical
grade sodium fluoride salt. Fluorosilicates have never been tested for
safety in humans. Furthermore, these industrial-grade chemicals are
contaminated with trace amounts of heavy metals such as lead, arsenic and
radium that accumulate in humans. Increased lead levels have been found in
children living in fluoridated communities. Osteosarcoma (bone cancer) has
been shown to be associated with radium in the drinking water. Long-term
ingestion of these harmful elements should be avoided altogether.
2.
Half of all ingested fluoride remains in the skeletal system and accumulates
with age. Several recent epidemiological studies suggest that only a few
years of fluoride ingestion from fluoridated water increases the risk for
bone fracture. The relationship between the milder symptoms of bone
fluorosis (joint pain and arthritic symptoms) and fluoride accumulation in
humans has never been investigated. People unable to eliminate fluoride
under normal conditions (kidney impairment) or people who ingest more than
average amounts of water (athletes, diabetics) are more at risk to be
affected by the toxic effects of fluoride accumulation.
3.
There is a dose-dependent relationship between the prevalence/severity of
dental fluorosis and fluoride ingestion. When dental decay rates were high,
a certain amount of dental fluorosis was considered an acceptable `trade
off' of providing an `optimum' dose of 1.0 ppm fluoride in the water.
However, studies published in the 1980's and 1990's have shown that dental
fluorosis has increased dramatically in North America. Infants and toddlers
are especially at risk for dental fluorosis of the front teeth since it is
during the first 3 years of life that the permanent front teeth are the most
sensitive to the effects of fluoride. Children fed formula made with
fluoridated tap water are at higher risk to develop dental fluorosis. A
relatively small percentage of the children affected with dental fluorosis
have the more severe kind that requires extensive restorative dental work to
correct the damage. The long-term effect of fluoride accumulation on dentin
colour and biomechanics is also unknown. Generalized dental fluorosis of all
the permanent teeth indicates that the bone is a major source of the excess
fluoride. The effect of this excess amount of fluoride in bone is unknown.
Whether stress bone fractures occur more often in children with dental
fluorosis has not been studied.
4.
A lifetime of excessive fluoride ingestion will undoubtedly have detrimental
effects on a number of biological systems in the body and it is illogical to
assume that tooth enamel is the only tissue affected by low daily doses of
fluoride ingestion. Fluoride activates G-protein and a number of cascade
reactions in the cell. At high concentrations it is both mitogenic and
genotoxic. Some published studies point to fluoride's interference with the
reproductive system, the pineal gland and thyroid function. Fluoride is a
proven carcinogen in humans exposed to high industrial levels. No study has
yet been conducted to determine the level of fluoride that bone cells are
exposed to when fluoride-rich bone is turned over. Thus, the issue of
fluoride causing bone cancer cannot be dismissed as being a non-issue since
carefully conducted animal and human cancer studies using the exact same
chemicals added to our drinking water have not been carried out.
The
issue of mass medication of an unapproved drug without the expressed
informed consent of each individual must also be addressed. The dose of
fluoride cannot be controlled. Fluoride as a drug has contaminated most
processed foods and beverages throughout North America. Individuals who are
susceptible to fluoride's harmful effects cannot avoid ingesting this drug.
This presents a medico-legal and ethical dilemma and sets water fluoridation
apart from vaccination as a public health measure where doses and
distribution can be controlled. The rights of individuals to enjoy the
freedom from involuntary fluoride medication certainly outweigh the right of
society to enforce this public health measure, especially when the evidence
of benefit is marginal at best.
Based on the points outlined briefly above, the evidence has convinced me
that the benefits of water fluoridation no longer outweigh the risks. The
money saved from halting water fluoridation programs can be more wisely
spent on concentrated public health efforts to reduce dental decay in the
populations that are still at risk and this will, at the same time, lower
the incidence of the harmful side effects that a large segment of the
general population is currently experiencing because of this outdated public
health measure.
Sincerely, Dr. Hardy Limeback BSc PhD (Biochemistry) DDS.
Head, Preventive Dentistry
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