There is a fair amount of prior art that concerns both cancer and
fluoride, but most of it is negative. We should begin this most important part with the most
authoritative reviews. I will give two.
The first is from two Englishmen, Richard Doll and Richard Peto. I highly
respect their work, in such diverse fields as inventing the modern clinical trial and meta analysis. They were among the first to prove connections between aspirin / (preventing) heart attacks and cigarettes
/ lung cancer.
In their 1981 book, "The Causes of Cancer", they remark that often in cancer work hard proof is not available, and
we have to use strong circumstantial evidence. They do not cover fluoride as
a food supplement, but they do cover fluoridated water. They dismiss the claims
that fluoridated water could cause cancer. They cite a study (we will cover it
later) in which fluoridated water did lower cancer slightly, and say that, "nobody seems to have claimed that fluoridation
prevents cancer." Indeed. In my
4 years of researching this question, that is the most positive statement I have seen.
The other authoritative review is by the United States Department of Health and Human Services. This was in 1991, following the cancer concerns raised by the NTP report about cancer in rats (which we
will get to later). This is a voluminous report, with almost 100 pages of review,
and almost 50 pages of references. They concluded that U.S.
policy should be to continue to use fluoridated water, and other fluoride products.
They did accept the results from the rat study, but overall said there is not an association between fluoride and cancer.
(See Mason JO, 1991. "Review of Fluoride, Risks and Benefits". DHHS, Washington DC 202-727-3312.)
Now let us go through some of the individual studies that are most relevant to using fluoride early in pregnancy to
prevent cancer. The most relevant to me are the ones on fluoridated water. Since pregnant women do drink the water, one could logically expect at least some
reduction if fluoride had that effect. Well, generally speaking there is no effect
In England, a check of about 2.6
million people, divided about evenly in fluoridated and non-fluoridated areas, found no overall association in 9 types of
cancer. At first glance, bone cancers did look a little lower in the fluoridated
area to me, at about 90% of what would have been expected, and the lowest of all the 9 ratios.
In contrast, the low fluoride areas had higher than expected rates of bone cancer, at about 120%, and this was the
highest of the 9 ratios. However, I doubt that this is statistically significant. Even if it were, this does not really relate to pregnancy because of one of the details. Most bone cancers are at a very specific age, about age 17. Most of the places in the test area had just started the fluoridation.
(The fluoridation was started from 1 to 13 years before, with a rough average of about 5 years.) Therefore we are not looking at fluoride in pregnancy versus not.
Leukemia, which occurs much earlier in childhood, at about 3 to 4 years, would have been a fair comparison. Unfortunately, leukemia rates were not checked. (Another part
of the report looked at naturally fluoridated areas, and bone cancers there showed no difference in higher or lower areas.)
(Kinlen L, 1975. Brit Dent J 138(6):221.)
In New Zealand a study did find
a slight preventive effect from fluoridated water (this is the one Peto noted above).
The cancer death rate in the fluoridated areas was about 93% of that in the non-fluoridated areas. However, once again this comparison is not about pregnancy. The
age group checked was age 45 years and up, and the fluoridation had only been going on for 13 years.
(Goodall CM, 1980. NZ Med J 92:164.)
The other very important point is that even if these studies had covered pregnancy, I do not think they would have
gotten enough fluoride from fluoridated water. The basis for that is the work
of Dr. Glenn on preventing pits and fissures. This test was in a fluoridated
area, yet 97% of the children still had pits and fissures if they did not get extra fluoride supplements. Although not as clearly, you also see that fluoridated water is not enough in studies of whether fluoridated
water during pregnancy makes a difference in dental caries. Most of them get
a minor positive result (like about 10%), compared to an average of 80% from supplements.
If I have learned only one thing from Dr. Glenn it is that fluoridated water does not supply enough fluoride during
(Pits and fissures: Glenn, 1984.
J Dent Child 51:19. Fluoridated water during pregnancy: Horowitz HS, 1967. Pub Health Rep 82:297.)
Fluoride has been used to prevent cancer, as long ago as 1946. However,
it was a massive dose, as a poison, and not during pregnancy.
(Tannenbaum A, 1946. Can Res 6:499, and, in 1949, Can Res 9:403. The rationale was that since low food intake prevents
cancer, what if metabolism was slowed down with a chronic poison. The test group
of mice was given .1 % NaF in their diet. This high fluoride reduced food intake
by 10% and weight gain by about a fourth. At the end of the test 74% of the control
group had cancer, versus 42% of the fluoride group. There was no suggestion that
fluoride itself prevented the cancer in any way other than by being a poison. Another
poison - dinitrophenol - had even better results. The relationship of fluoride
and cancer and birth defects are reviewed in 1966 by DiPaolo JA. Arch Path 81:3.)
(Fluoride compounds have been used to slow down tumour growth, but the active part of the compound was thought to be
tin. These workers thought cancer could be caused in part by a deficiency of
tin. See Cardarelli, 1984. Aust
J Exp Biol Med Sci 62(part 2):199 and 209.)
course, the biggest cancer story about fluoride in our time is the "NTP" (National Toxicology Program) report in 1990. I feel a little sheepish as I prepare to rip it to shreds, and you should bear in
mind that this study has been pretty well accepted by all reviewers.
(A free copy of the NTP report is available from the National Toxicology Program at 919-541-3991. "Toxicology and Carcinogenesis Studies of Sodium Fluoride". A
similar study that found no association is Maurer JK, 1990. J Nat Can Inst 82:1118.)
The report was that very high doses of fluoride probably caused an unusual type of osteosarcoma (bone cancer) in male
rats. This conclusion was well based on the following: When the water contained zero fluoride, there was zero bone cancer.
When the water had 11 ppm F (1 is normal fluoridated water), there was also zero.
When the water had 45 ppm, the first bone cancer shows up (2% of the animals), and when the water had 79 ppm, the bone
cancer rate went up to 4%. That is clearly a dose related response.
However undeniable this one line of data may be, there were about 120 other lines for other types of cancers and other
animals (female rats, male and female mice). None of these other lines showed
anything that the researchers were looking for. The point I would like to make
is that the general opinion that "fluoride is a poison" is so strong that no one looked for the opposite effect, of preventing
cancer. There was no comment that the rats that got no fluoride did not
do too well cancer wise either.
Looking at the same male rats, and at all types of cancer, the zero fluoride group had the highest cancer rates in
25 types of cancer. This is out of a total of 32, and compares to 7 out of 32
for the highest fluoride group. In the blood system cancers it was even more
dramatic: in 9 out of 11 cancer types the cancer was highest for the zero F group, versus a measly 2 out of 11 for the high
F group. These numbers, while impressive, do not really mean that much. By the time you add up all the lines for all the animals it all pretty much comes
out in the wash. (Although the lower fluoride groups do have slightly more -
not less - cancer, overall.) What is significant is that if this trial was on
vitamin A people would have set the statistics up to catch these "favorable" lines and trends.
(To be honest I did not catch these the first time I went through it either.
It was Dr. Darby Glenn who noticed the general trend. We should also note
that the fluoride in this trial was given to grown rats and mice, not during pregnancy.
The full NTP report is about 1 inch thick, and is available free of charge if you call 919-541-3991 and ask for the
NTP report on fluoride.)
The NTP report (and reviewers) also missed a few important references. The
obvious way to look for a fluoride association is to check the bones of the cancer patients.
(It is well known that about half of the fluoride that is consumed ends up stored in the bones, and it is an excellent
indicator of longterm fluoride intake. The DHHS reviewers did call for studies
As early as 1964 experts looked at the fluoride content of the bones of osteosarcoma patients. The results were pronounced as normal. However, the patients
in this series were born way before fluoride supplements became popular, and in my opinion the entire group was likely deficient. We do not know what the optimum level of fluoride is in bones. The levels in teeth in Dr. Glenn's well supplemented group are about twice that of children who grew up
in a fluoridated water area.
(Lucas HF, 1964. Science 144:1573.
Glenn FB, 1984. J Dent Child 51(5):344.
F w/ F H2O only .014%, w/ F H2O and PNF .035%)
There are general studies of fluoride levels in bone. Most are done by
autopsy, and generally do not include people under age 20 years for lack of samples.
Unfortunately, under 20 is the age of the people who get the vast majority of the bone cancer. But there is one Japanese study that did include some young people.
Here are the results, along with the normal incidence of bone cancer. (These
are two different populations, one in Japan, one in the USA.)
(0-9 yrs old)
These data clearly make it appear that if anything, osteosarcoma happens when the bones are the lowest in fluoride,
not the highest.
(Cancer cases: Unni KK, 1988. "Bone
Tumors", graph on page 108. F in bone:
Susuki Y, 1979. Tohoku J Exp Med 129:327.)
In my opinion the reason the bones of these young men are low in fluoride is because they are using it up faster than
they can take it in. There is no problem with young bones taking up fluoride
if it is available. In rats, young bones take it up about 2-4 times more than
old bones. In young dogs (this whole report is going to go to the dogs in a minute)
it is even more pronounced. When dogs are 6 weeks old, the bones will take (out
of their blood) 10 units of fluoride for every 1 the dog will clear by urine. By
the time the dog is 2 years old (growth mostly finished), the bones go 1 for 1 with the urine.
(Rats: WHO, 1970. "Fluorides
and Human Health" page 110. Dogs: Newbrun
E, 1986. "Fluoride and Dental Caries", page 187.)
Another way to look at this bone angle is to look at people who have ultra high fluoride in their bones. There are factories that use a high F mineral called cryolite. The
workers there take in 40 to 80 mg per day (that is a lot compared to a normal adult dose of .5 to 1 mg) from the dust. About 17% of the long term workers eventually end up with bone fluorosis bad enough
to be noticed. In this group of 431 men there were no cases of bone cancer or
any other cancers of the connective tissue. (Bear in mind most of these workers
would be over age 20, and only about a third of bone cancer cases happen then. The
expected number of total connective tissue cancers for this group would be .2, or almost zero anyway.) Lung cancers were about twice as what would have been expected in this group.
(Grandjean P, 1985. Amer J Epidem
The final (gasp) reference to look at that was missing in the NTP report is what happens to rat bones that get the
dose of fluoride that was given to them. (Some of the reviewers did catch that
the rats' cancer was in their backbones, not the usual long bones as in humans. The
difference is that long bones are "growers" mostly, and backbones are "remodelers", meaning they are constantly tearing themselves
down and rebuilding.)
In rats about the same age that got about the same doses as the NTP rats, there were changes that were visible in the
same back bones that got the cancer. "The resorption cavities ... have a distinct
resemblance to ... bone following radium radiation".
(Rockert H, 1963. Acta Pathologica Et Microbiologica Scandinavia 59:32.)
That is the end of the specific references that should have been included in the NTP paper about fluoride and bone
cancer. There are also two general ideas that really should have been stressed:
diet and growth.
Diet wise, we see that all three of the species that get osteosarcoma have artificial diets. Lab rats, humans, and dogs are the only animals I know of that get it.
In the humans we see the connection to growth in the sense that the osteosarcoma happens in the long growth bones,
and during the adolescent growth spurt. In dogs there is a similar connection.
Big dogs get it, little dogs do not. "Based on ... 404 cases studied,
the risk of bone sarcoma among giant dogs (over 80 lbs) is estimated to be no less that 61 times the risk among small dogs
(under 20 lbs), and possibly as high as 185 times the risk for small dogs." Anyone
who has raised a giant dog from a puppy knows what the difference is between big dogs and little dogs: growth, phenomenal growth. The risk in dogs goes up exponentially
with the size of the dog. The author thought that diet might be important: "malnutrition among puppies of the larger breeds is not uncommon and may, in turn,
be responsible for early defective bone formation which later results in bone sarcoma."
(Tjalma RA, 1966. J Nat Can Inst 36:1137.
An author who discusses the relationship between bone growth problems and osteosarcoma is Sutow WW, in his 1973 book,
"Clinical Pediatric Oncology". He notes that bone cancer seems to be predisposed
by various skeletal defects and a condition called fibrous dysplasia.)
There is other prior art that indirectly implies an association between cancer and what might be fluoride deficiency. This is, once again, looking for
people who say something like, "these kids with cancer sure have a lot of cavities".
most striking (to me) tie-in between fluoride and leukemia is a paper about a group of leukemia kids and their cavities. The cancer children had 5 times the rate of dental caries, compared to other children
in the neighborhood.
(In the study there were 111 children, 37 with cancer, and 74 healthy controls.
The controls, 2 for each cancer child, were selected from schoolfellows, of the same age, sex, and social background. These children were from Finland,
where all the children got similar dental care at community centers. Each child
would visit the dental center once per year, starting at age 3 years, so for most there were dental records long before the
children were diagnosed with cancer. All of the children lived in areas with
low fluoride in the water. The results:
"The mean dmfs [in effect, cavities: decayed, missing, filled surfaces] scores for the
primary dentition [baby teeth] were higher in the cancer group than in the controls, the differences being significant (p
< 0.01) at the ages of 4 and 5 years. The DMFS [cavities in permanent teeth]
values in children with cancer were also significantly higher (p < 0.05) than in the healthy controls at all ages above
8 years. The caries incidence before the diagnosis of leukemia and during its
therapy, and also during the treatment of other cancer disease, was 3-5 times higher than in the controls. Once the diseases had been cured, and before the diagnosis of any other forms of cancer, there was no difference
between the patients and the controls." The authors discuss various explanations,
more or less ruling all of them out. They do not even mention a fluoride deficiency,
and conclude: "The reason for the high caries incidence observed even before
diagnosis of leukemia ... remains obscure." Pajari U, 1988. Caries Res 22:318. In another paper the same author rules
out chemotherapy, finding it actually reduces caries. Scand J Dent Res 97:14.)
To be impressed by this next reference, you must assume that fluoride deficiency causes fast teeth. I think this is true, but I can not find any specific proof of that.
All we have is that teeth with fluoride - prenatal fluoride - are extra slow.
There is not even any statistical evidence of that, just a comment by one author that he found "a delay in the eruption
of the teeth, in some cases by as much as a year from the accepted eruption dates".
(Feltman G, 1961. Journal of Dental Medicine, 16(4):190. There are some great papers on what the normal variation is in eruption dates, and it is about 2 years. See Garn SM, 1959. J Dent Res 38(1):135. Garn has also shown that the timing of the eruption is set up in pregnancy, quite
early. Garn SM, 1971. J Dent
The main reference here is by the same author as the caries, Pajari, and the same care was taken to have a good control
group. The results were that the cancer kids' teeth were about a full year faster
than the controls.
(Most of the 38 cancer cases were leukemia cases - 24 -, and mostly acute lymphoblastic leukemia. The 14 other cases included 7 other types of childhood cancer. "The mean dental age of the children with
anti-cancer therapy was 12.3 years and that of the controls 11.4 years." Two
sample cases were presented, both with leukemia. The first was age 16, and had
the same dental age. The second case was age 10 years old and had the teeth of
a 16 year old. An interesting effect of the chemotherapy and radiation isp. Another author included some dental age information strictly on osteosarcoma patients. The results were "normal", but as I read them it appears the cancer children are about
1 month faster than the controls, on average, and the specifics are not given. Brostrom
LA, 1979. Acta Orthop Scand 51:755.)
Pits and fissures.
There are no articles about whether cancer patients have more or less pits and fissures in their teeth. However, there is one about bones. A German team looked at
how white blood cells leave the bone marrow after they are formed. There was
a difference between normal white blood cells and leukemic white blood cells. (The
fundamental problem is that in leukemia the blood cells get out of the bone marrow before they are mature.) In the leukemic bone marrows, it appears that the cell layer right above the basement membrane does not
cover it as well. It is not pits and fissures per se, but sort of analogous.
(Petrides PE, 1990. Blut 61:3. This article is an excellent
description of leukemia. Petrides says that leukemia is not caused simply and
only by a physical problem in the barrier. See below.)
we have two unrelated references in the prior art. In the Petrides article above,
he implies that the main problem is probably in the leukemia cells pulling off of the matrix prematurely. Some of the problem relates to collagen metabolism.
The other connection between cancer and prematurity is with the DES cases. DES
caused the cancer, but only in about 1 per 1,000 daughters exposed to it. If
the daughter were also born prematurely, she was more likely to get the cancer.
(See Herbst AL, 1990. Semin Surg Oncol 6(6):343.)
Let's look at DES just a little more. Let's focus on estrogen (DES is
synthetic estrogen) and matrix. If young mice are given estrogen, it causes major
changes in bone growth, especially in the bone marrow. Cancer of a special type
of white blood cell (lymphocytes) occur in about 10% of the mice.
(Gardner WU, 1944.
Cancer Res 4(2):73. See also Upton AC, 1966. Natl Cancer Inst Monogr 22:329.)
are some clues that almost tie in fluoride supplements and osteosarcoma in Sweden. A study found that the average age of the patients was changing, going up. Now with a long stretch, you could suggest this is related to the use of fluoride supplements. In other words, in the last 30 years since people started using fluoride, less young people - the ones
using it - are getting osteosarcoma.
(The connection is tenuous at best, and the study does not give the incidence by birth year, which could help tremendously. Stark A and Kreicbergs A, 1990. J Bone
Joint Surg 77-B(1):89. Since the average age of osteosarcoma is about 17 years,
the study covers births from roughly 1954 to 1967. Here is the schedule of F
supplements used over the years in Sweden,
from a letter from Dr. B Forsman:
Prenatal F Infant F Child F
1959 (Circular 101) yes
1971 (Circular 69) no
Primitive people did not have cancer. (And presumably had more fluoride.)
Dr. Weston Price "found entire cultures with neither tooth decay nor children with misshapen dental arches and crowded
teeth. He interviewed an American medical doctor living among Eskimos and northern
Indians who reported that in thirty-five years of observation, he had never seen a case of cancer among the primitives existing
on their native foods."
In other cultures in the Pacific, he noted that "the incidence of dental decay on a given island was directly proportional
to how long a store had been present. Children born after parents began using
refined foods often developed abnormal dental arches, as did a large majority of white children on Thursday
Island. The government physician for the Torres
Strait islanders stated that in his thirteen years with them, among the native population of four thousand he
had never seen a malignancy. He had operated on several dozen malignancies among
the white population of about three hundred."
(These quotes are out of "Traditional Foods Are Your Best Medicine", Schmid RF, 1987, pages 7 and 24. This is a great body of work, and Dr. Price suspected "some deficiency in modern diets caused the problems",
particularly during early pregnancy.)