The pineal gland is a small endocrine gland in the brain. The pineal gland produces melatonin, a serotonin-derived hormone which modulates sleep patterns in both circadian and seasonal cycles. The pineal gland is located in the epithalamus, near the center of the brain, between the two hemispheres, tucked in a groove where the two halves of the thalamus join. The gland is not protected by the blood brain barrier and has a very high perfusion rate of blood, second only to the kidney.
In 1997, Dr Jennifer Luke a British scientist showed that fluoride accumulation in the pineal gland of laboratory animals reduces melatonin production by the gland, resulting in earlier onset of puberty.
Melatonin is reponsible for regulating all kinds of activities and an extensive amount of work investigating its possible roles in aging, cancer and many other life processes. The one activity that Luke is particularly interested in is the onset of puberty. The highest levels of melatonin ( produced only at night) is generated in young children. It is thought that it is the fall of these melatonin levels which acts like a biological clock and triggers the onset of puberty. In her animal (gerbil) study she found that the high fluoride treated animals were reaching puberty earlier than the low fluoride animals.
In 2006, in their 3-year review “Fluoride in Drinking Water, the US National research Council stated “Fluoride is likely to cause decreased melatonin production and to have other effects on normal pineal function, which in turn could contribute to a variety of effects in humans.”
Luke hypothesized that one of the four enzymes needed to convert the amino acid tryptophan (from the diet) into melatonin is being inhibited by fluoride. It could be one of the two enzymes which convert tryptophan to serotonin or one of the two which convert serotonin to melatonin.
Several studies have shown that young girls are reaching puberty earlier and earlier in the US. Luke did not suggest that fluoride (or fluoridation) is the cause but her work certainly raises strong concerns. Fluoride’s role in earlier puberty needs more thorough investigation.
It is also worth mentioning here that in the Newburgh versus Kingston fluoridation trial (1945-1955), it was found that the girls in fluoridated Newburgh were reaching menstruation, on average, five months earlier than the girls in unfluoridated Kingston, but the result was not thought to be significant at the time (Schlessinger et al, 1956).
When Luke realised that the pineal gland was also a calcifying tissue, like the teeth and the bones, she hypothesized it would concentrate fluoride to very high levels. So in 2001, she had 11 corpses analyzed in the UK. As predicted she found extremely high levels of fluoride in the calcium hydroxy apatite crystals produced by the gland. The average was 9,000 ppm and went as high as 21,000 ppm in one case. These levels are at, or higher, than fluoride levels in the bones of people suffering from skeletal fluorosis.
It has also been suggested that the risk of breast cancer is related to the time between first menstruation and first pregnancy. If so, earlier onset of puberty for girls will, other things being equal, increases the risk of breast cancer later in life.
Dr Luke has stated she finds it “astonishing” that no follow up research has been done, given the serious implications of her research.
In 2019, in a study titled “Fluoride exposure and pubertal development in children living in Mexico City”, Yun Liu and his team of researchers stated: “We found a significant association between an increase in peripubertal fluoride exposure at the level observed in our study population and later pubertal development in Mexican boys at age 10–17 years.”
References and relevant studies
- Farkas G, et al. (1983). The fluoride content of drinking water and menarcheal age. Acta Univ Szeged Acta Biol. 29(1-4):159-168.
- Kunz D, et al. (1999). A new concept for melatonin deficit: on pineal calcification and melatonin excretion. Neuropsychopharmacology 21(6):765-72.
- Luke J. (2001). Fluoride deposition in the aged human pineal gland. Caries Res. 35(2):125-128.
- Luke J. (1997). The Effect of Fluoride on the Physiology of the Pineal Gland. Ph.D. Thesis. University of Surrey, Guildford.
- Mahlberg R, et al. (2009). Degree of pineal calcification (DOC) is associated with polysomnographic sleep measures in primary insomnia patients. Sleep Med. 10(4):439-45.
- National Research Council. (2006). Fluoride in Drinking Water: A Scientific Review of EPA’s Standards. National Academies Press, Washington D.C.
- Schlesinger ER, et al. (1956). Newburgh-Kingston caries fluorine study. XIII. Pediatric findings after ten years. J Am Dent Assoc. 52(3):296-306.