Tag Archives: fluoride

All Sources of Fluoride Must be Considered

Norman M, Twetman S, Hultgren Talvilahti A, Granström E, Stecksén-Blicks C. Urinary fluoride excretion in preschool children after intake of fluoridated milk and use of fluoride-containing toothpaste. Community Dent Health. 2017 Mar;34(1):27-31. doi: 10.1922/CDH_3943Norman05.

OBJECTIVE: To assess the urinary fluoride excretion in preschool children after drinking fluoridated milk with 0.185 mg F and 0.375 mg F and to study the impact of use of fluoride toothpaste.

BASIC RESEARCH DESIGN: Double-blind cross-over study.

PARTICIPANTS: Nine healthy children, 2.5-4.5 years of age.

INTERVENTION: In a randomized order, participants drank 1.5 dl milk once daily for 7 days with no fluoride added (control), 0.185 mg fluoride added and 0.375 mg fluoride added. The experiment was performed twice with (Part I) and without (Part II) parental tooth brushing with 1,000 ppm fluoride toothpaste. The fluoride content in the piped drinking water was 0.5 mg F/L.

MAIN OUTCOME MEASURE: Urinary fluoride excretion.

RESULTS: The 24-hour urinary fluoride excretion/kg body weight varied from 0.014 mg F for the placebo intervention and non-fluoride toothpaste to 0.027 mg F for the 0.375 mg intervention with use of 1,000 ppm fluoride toothpaste. The difference compared with the placebo intervention was not statistically significant for any of the interventions when fluoride toothpaste was used (p⟩0.05) while it was statistically significantly different when non-fluoride toothpaste was used (p⟨0.05).

CONCLUSIONS: All sources of fluoride must be considered when designing community programs. With 0.5 mg F/L in the drinking water and daily use of fluoride toothpaste, most children had a fluoride intake optimal for dental health. In this setting, additional intake of fluoride milk was within safe limits up to 0.185 mg/day while conclusions about the safety of 0.375 mg/day were uncertain.

Fluoride kidney toxicity

Antonio LS, Jeggle P, MacVinish LJ, Bartram JC, Miller H, Jarvis GE, Levy FM, Santesso MR, Leite AL, Oliveira RC, Buzalaf MA, Edwardson JM. The effect of fluoride on the structure, function, and proteome of a renal epithelial cell monolayer. Environ Toxicol. 2017 Apr;32(4):1455-1467. doi:10.1002/tox.22338

High concentrations of fluoride in the body may cause toxic effects. Here, we investigated the effects of fluoride on the structure, function, and proteome of a cortical collecting duct epithelium in vitro. Kidney tubule cells (M-1) were chosen because the concentration of fluoride in the kidney is 4-5-fold higher than that in plasma. Mouse M-1 cell monolayers were incubated in fluoride-containing media, and the amiloride-sensitive short-circuit current and transepithelial resistance were measured. The Young’s modulus of the epithelium was determined using atomic force microscopy, and the effect of fluoride on epithelial structure was assessed using scanning and transmission electron microscopy, and immunofluorescence. Differences in the expression of membrane proteins were evaluated using proteomics and bioinformatics. Fluoride exposure reduced both transepithelial Na+ transport and resistance. The IC50 for fluoride was ∼300 µM for both effects, and the half-times for the decays of ion transport and resistance were 8.4 h and 3.6 days, respectively. Fluoride treatment did not affect the sensitivity of Na+ transport to amiloride. The Young’s modulus of the epithelium was also unaffected by fluoride; however, the functional effects of fluoride were accompanied by marked structural effects. Proteomic analysis revealed changes in expression of a number of proteins, and particularly mitochondrial proteins. Treatment with fluoride had profound effects on the structure, function and proteome of a model cortical collecting duct epithelium. Significantly, however, these effects were produced only at concentrations considerably higher than those likely to be encountered in vivo.

Chronic Excessive Fluoride Intake Adversely Affects Cardiovascular Systems

Yan X, Wang L, Yang X, Qiu Y, Tian X, Lv Y, Tian F, Song G, Wang T. Fluoride induces apoptosis in H9c2 cardiomyocytes via the mitochondrial pathway.  Chemosphere. 2017 May 1;182:159-165. doi: 10.1016/j.chemosphere.2017.05.002.

Numerous studies have shown that chronic excessive fluoride intake can adversely affect different organ systems. In particular, the cardiovascular system is susceptible to disruption by a high concentration of fluoride. The objectives of this study were to explore the mechanism of apoptosis by detecting the toxic effects of different concentrations of sodium fluoride (NaF) in H9c2 cells exposed for up to 96 h. NaF not only inhibited H9c2 cell proliferation but also induced apoptosis and morphological damage. With increasing NaF concentrations, early apoptosis of H9c2 cells was increased while the mitochondrial membrane potential was decreased. Compared with the control group, the mRNA levels of caspase-3, caspase-9, and cytochrome c all increased with increasing concentrations of NaF. In summary, these data suggest that apoptosis is involved in NaF-induced H9c2 cell toxicity and that activation of the mitochondrial pathway may occur.

Fluoride content of tea infusions, Portugal

Linhares DP, Garcia PV, Amaral L, Ferreira T, Dos Santos Rodrigues A. Safety Evaluation of Fluoride Content in Tea Infusions Consumed in the Azores-a Volcanic Region with Water Springs naturally Enriched in Fluoride. Biological trace element research. 2017 Jan 24. doi: 10.1007/s12011-017-0947-9.

Tea is the second most commonly consumed beverage in the world. It is well recognized that the consumption of tea in high quantities can promote the development of fluorosis. The main objective of this study is to estimate the exposure to fluoride in the Azores through drinking tea prepared with water from different volcanic locations, by i) investigating the fluoride (F) content of various commercial brands of tea (Camellia sinensis) marketed in Azores and ii) comparing tea releasing rates of F according to brewing time, considering the fluoride concentration in the different types of water used for the infusion. Fluoride contents were determined by ion-selective electrode in 30 samples of drinking water from three different locations and in 450 samples of tea (black and green tea) from three different brands. Fluoride concentration in water ranged from 0.29 to 1.56 ppm (Porto Formoso and Sete Cidades village, respectively). Fluoride concentrations increased with brewing time, reaching the highest values in the Azorean black and green tea infusions. For all the studied brands, a negative correlation was found between tea fluoride contents and the pH of the water used to prepare the infusion. Fluoride concentration in infusions was significantly associated with the background fluoride concentration in drinking water. Since the fluoride concentration in groundwater varies accordingly to the geological conditions and tea consumption can contribute to fluoride intake, it is important to define the limits for tea consumption, particularly in fluoride-rich areas.

Fluoride, Trace Metals, and Hardness have Synergistic Effect on Kidney Tissues?

Wasana HM, Perera GD, Gunawardena PS, Fernando PS, Bandara J. WHO water quality standards Vs Synergic effect(s) of fluoride, heavy metals and hardness in drinking water on kidney tissues. Scientific reports 2017 Feb 14;7:42516. doi: 10.1038/srep42516.

Despite WHO standards, waterborne diseases among the human being are rising alarmingly. It is known that the prolong exposure to contaminated water has major impact on public health. The effect of chemical contaminations in drinking water on human being is found to be chronic rather than acute and hence can be defined “consumption of contaminated drinking water could be a silent killer”. As the WHO recommended water quality standards are only for individual element and synergic effects of trace metals and anions have not been considered, investigation of synergic effects of trace metals and anions and their effect on human being is of prime important research. By an animal trial, we investigated the synergic effect(s) of heavy metals, aluminium, arsenic, fluoride and hardness in drinking water on kidney tissues of mice. Our investigation strongly suggests existing of a synergic effect especially among Cd, F and hardness of water which could lead to severe kidney damage in mice, even at WHO maximum recommended levels. Hence, the synergic effect(s) of trace metals, fluoride and hardness present in drinking water should be investigated meticulously when stipulating the water quality at WHO maximum recommended levels.

Fluoride Toxicity – A Harsh Reality

Bandlapalli Pavani, Mandava Ragini, David Banji, Otilia J F Banji, N Gouri Pratusha. Fluoride Toxicity – A Harsh Reality. International Research Journal of Pharmacy, Vol 2, Iss 4, Pp 79-85 (2011).

There are many incidents of fluoride toxicity whether it is acute or chronic. Fluoride toxicity is an environmental hazard which arises from the upper layers of geological crust and is dissolved in water. Prolonged drinking of such water causes chronic fluoride toxicity. Use of fluoride containing compounds for various purposes such as dental products, metal, glass, refrigerator and chemical industries act as a source of fluoride poisoning and increase the risk of toxicity. This review reflects the deleterious effects of fluorides on various organs in the physiological system.

Fluoride Toxicity and Cognitive Impairment; China

Spittle B. Development of Fluoride Toxicity Including Cognitive Impairment with Reduced IQ: Pathophysiology, Interactions With Other Elements, and Predisposing and Protective Factors. Fluoride. Jul-Sep2016, Vol. 49 Issue 3, Part 1, p189-193.

The development of toxicity to the fluoride ion (F) may be complex and multifactorial with a number of pathophysiological path ways being possible, with the potential for interactions between toxins involving additivity, synergism, and antagonism, and with a number of other factors having predisposing and protective effects. In addition to cognitive impairment with a reduced intelligence quotient (IQ) in children developing through other mechanisms such as disturbed thyroid hormone metabolism and sonic hedgehog signalling, other pathophysiological factors such as reduced brain glucose uptake following a fluoride-induced reduction in insulin secretion may contribute. Environmental contamination with cadmium in a coal combustion fluorosis-affected rural area within China’s Three Gorges region may contribute to the dental and skeletal health problems in the population and the possibility of interactions between Cd and F affecting cognitive functioning requires further investigation. The propensity for the development of toxicity to F may involve interactions with a number of other factors as well as the levels of F exposure.