UNDERSTANDING THE SCIENCE OF FLUORIDE
Fluoride Facts
The Brain
The brain is the most complex organ, controlling every metabolic process and other organ in the body. Many are concerned with the effects fluoride has on this structure, especially on the topic of cognitive impairment and neurological dysfunction.
Fluoride and IQ
Those who are vocally against the process of fluoride in water, purport that fluoride adversely affects IQ. The main source that “supports” this claim is a meta-analysis conducted by Anne Choi, Guifan Sun, Ying Zhang, and Philippe Grandjean, a team affiliated with the Harvard Public Health School. They pulled studies from MEDLINE, EMBASE, TOXNET, and the China National Knowledge Infrastructure database. Eventually they identified 27 eligible studies with high exposures with correlation between IQ scores and cognitive function measures. They used a random-effects model, and this showed that children in areas with high fluoride exposure had substantially lower IQ scores than those who lived in low-fluoride areas. However, the study had a major methodological limitation:
“Our review cannot be used to derive an exposure limit, because the actual exposures of the individual children are not known. Misclassification of children in both high- and low-exposure groups may have occurred if the children were drinking water from other sources (e.g., at school or in the field).”
Although this meta-analysis shows the risks of fluoride on IQ, the voids where other variables are not accounted for and the extremely high exposure to fluoride renders this study discrepant to the effective use of fluoride in developed countries. The studies were conducted in: China, India, Iran, and Mexico - countries that have a high level of naturally occurring fluoride in the water and possibly other toxic substances that were not measured. The fluoride levels in water were also four times the optimum level recommended by the PHS. Given this information the results of the study are not comparable to regulated water fluoridation of countries like the United States
Brain via The Wire
Fluoride and the Pineal Gland
A common concern among those skeptical of the effects of fluoride assert that the pineal gland in particular is adversely affected. Only one study is found to claim that fluoride accumulation in the brain causes cancer, alzheimer's, and other detrimental effects - a dissertation by Dr. Jennifer Luke from the University of Surrey.
The pineal gland is a small endocrine gland that has been only recently found to produce a hormone called melatonin, which regulates sleep/wake cycles - thus also being known as the human circadian clock. Secretions of melatonin are varied throughout the day but peak during nighttime due to its production being triggered by the amount of light exposure to the eyes. It has been understood that fluoride and calcium deposits accrue in the pineal gland, but their definitive effect is unknown. It has been theorized that these accumulations might have an effect on melatonin production and possibly puberty, which was a conjecture made by Luke.
The fluoride concentration in the study was measured from 11 aged human pineals and corresponding muscles, with the result found being that the fluoride concentration in the pineal was significantly higher than the muscle. The second part of the paper was a controlled longitudinal experimental study, with the purpose to find if this concentration affects biosynthesis of melatonin and any pubertal developmental effects, using 2 groups of mongolian gerbils with different exposures levels.
The conclusion found that the fluoride accumulation inhibits pineal melatonin synthesis in gerbils up until the time of sexual maturation; the accumulation was also associated with a significant acceleration of pubertal development in female gerbils. One problem with this study is that the findings of inhibited biosynthesis of melatonin and premature puberty of females in the gerbils does not necessarily mean that it relates to human physiology.
Another issue is that the 11 cadavers used to measure fluoride concentration in the pineal gland had an average age of 82 years, in which fluoride has been found to naturally accumulate in the pineal gland, with or without fluoridation.
In Luke’s 2001 revisal of this dissertation, she herself finds that fluoride deposition and calcification is age-related. A later study done in Turkey also confirms the age-relatedness to calcium concentration, by measuring these concentrations from the pineal gland in persons in various stages of life while taking climatological effects into account. The results concluded that there was a link between the amount of calcification present and age, and even going as far as discovering the ascendancy of it in males compared to females. Further research may be preferable to explore this phenomenon, although it is clear that this is not detrimental to populations with regulated CWF programs.
Sources
1. Luke, J. (1997). The Effects of Fluoride on the Physiology of the Pineal Gland.
PhD ThesisUniversity of Surrey, Guildford.
2. Choi, A. L., Sun, G., Zhang, Y., & Grandjean, P. (2012).Developmental Fluoride
Neurotoxicity:A Systematic Review and Meta-Analysis.Environmental Health Perspectives, 120(10), 1362–1368. http://doi.org/10.1289/ehp.1104912