Fluoride exposure from infant formula and child IQ in a Canadian birth cohort

Mechanisms of Fluoride Toxicity: From Enzymes to Underlying Integrative Networks

Fluoride has been employed in laboratory investigations since the early 20th century. These studies opened the understanding of fluoride interventions to fundamental biological processes. Millions of people living in endemic fluorosis areas suffer from various pathological disturbances. The practice of community water fluoridation used prophylactically against dental caries increased concern of adverse fluoride effects. We assessed the publications on fluoride toxicity until June 2020. We present evidence that fluoride is an enzymatic poison, inducing oxidative stress, hormonal disruptions, and neurotoxicity. Fluoride in synergy with aluminum acts as a false signal in G protein cascades of hormonal and neuronal regulations in much lower concentrations than fluoride acting alone. Our review shows the impact of fluoride on human health. We suggest focusing the research on fluoride toxicity to the underlying integrative networks. Ignorance of the pluripotent toxic effects of fluoride might contribute to unexpected epidemics in the future.

A systematic comparison between infant formula compositions using the Bray-Curtis Similarity Index

BACKGROUND

Making an informed choice between the available infant formulas is challenging, as there is no unbiased tool allowing a systematic comparison between the very long lists of infant formula compositions.

AIM

The aim is to present the Bray-Curtis Similarity Index (BCSI) as a tool for systematic comparison between standard stage-1 infant formula (SS-1-IF) compositions.

METHODS

We obtained the nutrient levels from the packaging labels of 23 SS-1-IFs available in Al-Ahsa, Saudi Arabia, in April 2018. The international legislations that launched infant formula standards endorse targeting the minimum rather than the maximum proposed nutrients levels. Thus, we blindly compared between displayed nutrients levels on each of the 23-studied SS-1-IF and the minimum international proposed nutrient levels via using the BCSI.

RESULTS

The range of the total displayed components was 38-57. Except for docosahexaenoic acid, all displayed components were within the standard recommended range. The BCSI summarized all displayed nutrients in a single number. The BCSI of the studied SS-1-IF ranged from 0.4141 to 0.79730. We ranked the 23 studied SS-1-IFs based on the higher BCSI is the closer to the minimum proposed nutrient levels. A dendrogram segregated the SS-1-IFs into four clusters based on their BSCI and total numbers of all displayed components.

CONCLUSIONS

We think the BCSI is an appropriate tool for a systematic comparison between SS-1-IFs compositions and may help for choosing a SS-1-IF.

Developmental fluoride neurotoxicity: an updated review

BACKGROUND

After the discovery of fluoride as a caries-preventing agent in the mid-twentieth century, fluoridation of community water has become a widespread intervention, sometimes hailed as a mainstay of modern public health. However, this practice results in elevated fluoride intake and has become controversial for two reasons. First, topical fluoride application in the oral cavity appears to be a more direct and appropriate means of preventing caries. Second, systemic fluoride uptake is suspected of causing adverse effects, in particular neurotoxicity during early development. The latter is supported by experimental neurotoxicity findings and toxicokinetic evidence of fluoride passing into the brain.

METHOD

An integrated literature review was conducted on fluoride exposure and intellectual disability, with a main focus on studies on children published subsequent to a meta-analysis from 2012.

RESULTS

Fourteen recent cross-sectional studies from endemic areas with naturally high fluoride concentrations in groundwater supported the previous findings of cognitive deficits in children with elevated fluoride exposures. Three recent prospective studies from Mexico and Canada with individual exposure data showed that early-life exposures were negatively associated with children's performance on cognitive tests. Neurotoxicity appeared to be dose-dependent, and tentative benchmark dose calculations suggest that safe exposures are likely to be below currently accepted or recommended fluoride concentrations in drinking water.

CONCLUSION

The recent epidemiological results support the notion that elevated fluoride intake during early development can result in IQ deficits that may be considerable. Recognition of neurotoxic risks is necessary when determining the safety of fluoride-contaminated drinking water and fluoride uses for preventive dentistry purposes.