SCIENCE
WATCH Newsletter: Fluoride & the
Brain
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FAN SCIENCE-WATCH
February 22, 2004
Bulletin #1: Fluoride & the Brain
Hey everyone,
The goal of this newsletter will be to keep FAN members abreast
of the latest studies and reports on fluoride’s toxicity.
Many of the studies and reports which we will be posting –
like the one below – come directly from the US National
Library of Medicine’s online database PubMed. See: http://www.ncbi.nlm.nih.gov/PubMed/
One of the benefits of PubMed is that it picks up studies written
in other languages that would otherwise be inaccessible to the
English speaking world. This is particularly important with
a subject like fluoride, since much of the key research on fluoride
& health is currently being conducted in China and India
– where researchers aren’t thwarted by the type
of political obstacles that make intelligent research in the
United States so difficult.
The recent experience of the US scientist Dr.
Phyllis Mullenix is a particularly telling example of the
political obstacles thwarting good, essential research in the
US – see http://www.fluoridealert.org/mullenix-interview.htm
. Whereas Dr. Mullenix got fired for publishing results suggesting
that fluoride was a neurotoxin (i.e. that it damaged the brain),
researchers in China are now regularly reaching this conclusion.
Instead of getting fired, however, these China scientists seem
able to secure more funding for additional research.
The most recent Chinese study on fluoride
& the brain was posted on PubMed just last week (see
abstract below). The study looked at the effect of fluoride
on the hippocampal region of rat brain, and concluded that:
“Fluoride may go through the blood-brain barrier and accumulate
in rat hippocampus, and inhibit the activity of cholinesterase.”
These findings are of particular interest in light of Mullenix’s
own findings. According to Mullenix (1995):
“Hyperactivity and cognitive deficits are generally
linked with hippocampal damage, and in fact, the hippocampus
is considered to be the central processor which integrates
inputs from the environment, memory, and motivational stimuli
to produce behavioral decisions and modify memory... Overall,
the behavioral changes from fluoride exposure are consistent
with interrupted hippocampal development. Whether the hippocampus
is indeed the brain region most susceptible to fluoride is
a possibility deserving consideration in future studies”
Below, I have posted the full abstract of the new study. I
have also posted a bibliography (in chronological order) of
recent studies on fluoride & the brain.
Michael Connett
Editor, FAN Science Watch
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NEW STUDY on F/BRAIN:
Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi. 2003
Apr;21(2):102-4.
[Studies on fluoride concentration and cholinesterase activity
in rat hippocampus]
[Article in Chinese]
Zhai JX, Guo ZY, Hu CL, Wang QN, Zhu QX.
School of Public Health, Anhui Medical University, Hefei 230032,
China.
OBJECTIVE: To study the accumulation of fluoride in rat hippocampus
and its effect on cholinesterase activity. METHODS: Rats were
subchronically exposed to NaF, and fluoride concentration and
cholinesterase activity in rat hippocampus were determined.
RESULTS: Fluoride concentration in rat hippocampus was significantly
correlated with the dosage of fluoride, and there were significant
differences among high dosage group [(13.03 +/- 1.79) micro
g/g], low dosage group [(9.83 +/- 0.92) micro g/g] and control
[(8.27 +/- 1.11) micro g/g], P < 0.01.Acetylcholinesterase
activities among three groups [(0.111 +/- 0.031) micro mol/mg,
(0.143 +/- 0.025) micro mol/mg, (0.183 +/- 0.027) micro mol/mg]
were also significantly different (P < 0.01), which was negatively
correlated with fluoride concertration in rat hippocampus (r
= -0.700, P < 0.01). The activity of butylcholinesterase
in high dosage group [(0.041 +/- 0.010) micro mol/mg] was different
from that of control [(0.067 +/- 0.025) micro mol/mg, P <
0.05], but the activity was not significantly related with fluoride
concertration in rat hippocampus (r = -0.317, P = 0.094). CONCLUSION:
Fluoride may go through the blood-brain barrier and accumulate
in rat hippocampus, and inhibit the activity of cholinesterase.
PMID: 14761523 [PubMed - in process]
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FLUORIDE
& THE BRAIN: RECENT STUDIES:
Chen J, et al. (2003). Selective decreases of nicotinic acetylcholine
receptors in PC12 cells exposed to fluoride. Toxicology
183(1-3):235-42.
Shashi A. (2003). Histopathological investigation of fluoride-induced
neurotoxicity in rabbits. Fluoride 36: 95-105.
Xiang Q, et al. (2003). Effect of fluoride in drinking water
on children's intelligence. Fluoride 36: 84-94.
Zhai JX, et al. (2003). [Studies on fluoride concentration
and cholinesterase activity in rat hippocampus]. Zhonghua
Lao Dong Wei Sheng Zhi Ye Bing Za Zhi 21(2):102-4.
Long YG, et al. (2002). Chronic fluoride toxicity decreases
the number of nicotinic acetylcholine receptors in rat brain.
Neurotoxicology and Teratology 24(6):751-7.
Bhatnagar M, et al. (2002). Neurotoxicity of fluoride: neurodegeneration
in hippocampus of female mice. Indian Journal of Experimental
Biology 40: 546-54.
Chen J, et al. (2002). [Studies on DNA damage and apoptosis
in rat brain induced by fluoride] Zhonghua Yu Fang Yi Xue
Za Zhi 36(4):222-224.
Shivarajashankara YM , et al. (2002). Brain lipid peroxidation
and antioxidant systems of young rats in chronic fluoride intoxication.
Fluoride 35: 197-203.
Shivarajashankara YM , et al. (2002). Histological changes
in the brain of young fluoride-intoxicated rats. Fluoride
35(1): 12-21.
Ekambaram P, Paul V. (2001). Calcium preventing locomotor behavioral
and dental toxicities of fluoride by decreasing serum fluoride
level in rats. Environmental Toxicology and Pharmacology
9(4):141-146.
Zhang Z, et al. (2001). [Effects of selenium on the damage
of learning-memory ability of mice induced by fluoride]. Wei
Sheng Yan Jiu. 30(3):144-6.
Calderon J, et al. (2000). Influence of fluoride exposure on
reaction time and visuospatial organization in children. Epidemiology
11(4): S153.
Lakshmi Vani M, Pratap Reddy K. (2000). Effects of fluoride
accumulation on some enzymes of brain and gastrocnemius muscle
of mice. Fluoride 33: 17-26.
Lu XH, et al. (2000). Study of the mechanism of neurone apoptosis
in rats from the chronic fluorosis. Chinese Journal of Epidemiology
19: 96-98.
Lu Y, et al (2000). Effect of high-fluoride water on intelligence
of children. Fluoride 33:74-78.
Shao Q, et al. (2000). [Influence of free radical inducer on
the level of oxidative stress in brain of rats with fluorosis].
Zhonghua Yu Fang Yi Xue Za Zhi 34(6):330-2.
Sun ZR, et al. (2000). Effects of high fluoride
drinking water on the cerebral functions of mice. Chinese
Journal of Epidemiology 19: 262-263.
Sarri E, Claro E. (1999). Fluoride-induced
depletion of polyphosphoinositides in rat brain cortical slices:
a rationale for the inhibitory effects on phospholipase C. International
Journal of Developmental Neuroscience 17(4):357-67.
van der Voet GB, et al. (1999). Fluoride enhances the effect
of aluminium chloride on interconnections between aggregates
of hippocampal neurons. Archives of Physiology and Biochemistry
107(1):15-21.
Zhang Z, et al. (1999). [Effect of fluoride exposure on synaptic
structure of brain areas related to learning-memory in mice]
[Article in Chinese]. Wei Sheng Yan Jiu 28(4):210-2.
Calvert GM, et al. (1998). Health effects associated with sulfuryl
fluoride and methyl bromide exposure among structural fumigation
workers. American Journal of Public Health 88(12):1774-80.
Guan ZZ, et al (1998). Influence of chronic fluorosis on membrane
lipids in rat brain. Neurotoxicology and Teratology
20: 537-542.
Paul V, et al. (1998). Effects of sodium fluoride on locomotor
behavior and a few biochemical parameters in rats. Environmental
Toxicology and Pharmacology 6: 187–191.
Varner JA, et al. (1998). Chronic administration of aluminum-fluoride
and sodium-fluoride to rats in drinking water: Alterations in
neuronal and cerebrovascular integrity. Brain Research 784:
284-298.
Zhao XL, Wu JH. (1998). Actions of sodium fluoride on acetylcholinesterase
activities in rats. Biomedical and Environmental Sciences
11(1):1-6
Issacson R, et al. (1997). Toxin-induced blood vessel inclusions
caused by the chronic administration of aluminum and sodium
fluoride and their implications for dementia. Annals of
the New York Academy of Science 825: 152-166.
Wang Y, et al. (1997). [Changes of coenzyme Q content in brain
tissues of rats with fluorosis]. Zhonghua Yu Fang Yi Xue
Za Zhi. 31: 330-3.
Zhao LB, et al (1996). Effect of high-fluoride water supply
on children's intelligence. Fluoride 29: 190-192.
Li XS. (1995). Effect of Fluoride Exposure on Intelligence
in Children. Fluoride 28(4):189-192.
Mullenix P, et al. (1995). Neurotoxicity of Sodium Fluoride
in Rats. Neurotoxicology and Teratology 17:169-177.
Li Y, et al. (1994). [Effect of excessive fluoride intake on
mental work capacity of children and a preliminary study of
its mechanism] Hua Hsi I Ko Ta Hsueh Hsueh Pao. 25(2):188-91.
Shashi A, et al. (1994). Effect of long-term administration
of fluoride on levels of protein, free amino acids and RNA in
rabbit brain. Fluoride 27: 155-159.
Yang Y, et al. (1994). [Effects of high iodine and high fluorine
on children's intelligence and the metabolism of iodine and
fluorine]. Zhonghua Liu Xing Bing Xue Za Zhi.15(5):296-8.
Du L. (1992). [The effect of fluorine on the developing human
brain]. Chung-hua Ping Li Hsueh Tsa Chih. 21(4):218-20.
Lin Fa-Fu; et al (1991). The relationship of a low-iodine and
high-fluoride environment to subclinical cretinism in Xinjiang.
Iodine Deficiency Disorder Newsletter Vol. 7. No. 3.