# Fluoride and Pineal Gland
## 4 Fluoride Accumulation in the Pineal Gland and Its Consequences  
Both calcified and calcium-free areas of the pineal gland undergo mineralization and accumulate, among other things, magnesium, iron, manganese, zinc, strontium, or copper [105]. However, it was not until the 1990s that it was discovered that the foci of calcification within the gland may be accompanied by extremely high concentrations of fluoride for soft tissue [54]. In 2001, [PERSON] [52] first published the results of fluoride concentration measurements in pineal glands taken from human corpses. The mean concentration was 297 mg F/kg of wet weight (ww), but the range of recorded values was very wide (14 mg/kg-875 mg/kg ww). It is not difficult to notice that they are similar or even higher than those observed in bones and teeth and many times exceed the concentrations observed in other soft tissues (e.g., in muscles, they are about 1 mg F/kg ww). After converting these values into dry weight (dw), we obtain concentrations of 1485 + 1285 mg F/kg dw. Although these data come from older individuals (studies were conducted on a group of deceased people aged 70 to 100 years), this does not disprove the idea that the pineal gland may be considered the most fluoride-saturated organ of the human body. It has been observed that the fluoride content in pineal gland apatite is higher than in any other natural apatite and may even reach 21000 mg/kg [52; 53]. The results of [PERSON]'s research also revealed a strong positive correlation between calcium and fluoride concentrations (r = 0.73, \(p\) < 0.02) [52]. Ten or so years later this observation was confirmed, albeit not for the full range of fluoride concentrations. [PERSON] et al. [53] demonstrated that a statistically significant correlation occurs only when the fluoride concentration exceeds 50 mg/kg of fresh gland tissue. They recorded the values of these concentrations, which ranged anywhere from 0 mg F/kg ww to 831 mg F/kg ww (mean 75.5 + 228 mg F/kg ww). This suggests that the accumulation of fluoride in the pineal gland is rather a secondary phenomenon to the primary calcification of this organ and at some point the relation between them reaches the status of a very strong positive correlation (r = 0.915, \(p\) < 0.001). It is also worth noting that pineal glands in the study by [PERSON] et al. [53] were collected from deceased persons aged 33 to 91 years (mean 67 years), who had inhabited an area with low fluoride contamination, which is a strong argument for the idea that a smaller or larger accumulation of fluoride in the gland occurs even when the organism is not exposed to particularly large amounts of fluorine compounds in the environment. Regardless of how accumulation of fluoride in the pineal gland takes place, whether this is primary or secondary to calcification, the most important issue is the effects of this phenomenon. It is obvious that they will primarily concern the physiological function of the gland. Assuming the preferential accumulation of fluoride in the pineal gland and the related possible risk of toxic effects, [PERSON] et al. [11] have recently published a study on the processes of sleep regulation among older adults in the United States. They tried to answer the question of whether chronic exposure to low doses of fluoride has an effect on sleep patterns and daytime sleepiness in the studied population. The study investigated adolescents aged 16-19 years (mean = 17 years), who had declared that they had no sleeping disorders, who were exposed to low doses of fluoride (mean concentration in drinking water = 0.39 mg/L), and who had low concentrations of fluoride in plasma (mean = 0.35 umol/L). Higher water fluoride levels were connected with higher odds of participants reporting snorting, gasping, or apnea, while sleeping at night. Additionally, adolescents who lived in areas with higher fluoride levels in tap water experienced more frequent daytime sleepiness.