[Junk Sciences] Fluoride, aluminium and the brain……when pseudosciences defies high-school chemistry

Today, I am writing about a question posted by “Bobbi Morse”, one follower on my Facebook about that quote from William Douglass, MD. Dont let be fooled by the title, it turns out having a medical degree unfortunately does not make you immune to conspiracy theories. Indeed Mr. Douglass thinks that AIDS is a conspiracy directed by the WHO to reduce the African population as the evil New World Order plot (you can read more on his profile on that Wiki page http://rationalwiki.org/wiki/William_Campbell_Douglass)
If you want to assess the robustness of a message, you should assess the credential of his messenger and Mr. Douglass one is pretty insane.

So here we have three things that are completely unrelated : fluoride, aluminum and Alzheimer’s

Fluoride (F) is an halogen element from the same period column than chloride (Cl) and bromine (Br). In our daily uptake (water and food), fluoride is present as an anion form (F-). Fluoride biological function is fairly limited but there is one thing that it is playing an important role: enamel conservation and tooth decay. You all know that eating excessive sugar is bad for your teeth. The reason behind it is that sugar is transformed into lactic acid by fermentation from your mouth microbiota, as these bacteria use sugar as a source of energy. This acid production results in the decrease in pH (because you are acidifying the environment) enough to begin the dissolution of the hydroxyapatite present your enamel and induce your teeth to decay. Now, fluoride (F-) can bind to hydroxyapatite forming the fluorapatite that is much more insoluble and keep it inside your enamel. This has been shown that adding just a little bit of fluoride in the drinking water was enough to reduce the occurence of tooth decay in the population. A smart public health move and surprisingly enough backed by most dentists (if there was a Big Dentist out making profit of canal roots, bridges and fillings, it would have worked hard to remove fluoridated water).

Aluminum (Al) is a post-transition metal and sometimes also classified as a metalloid. I will not discuss more about it since I have discussed about in details in a previous post (see the post of aluminum nanoparticles in vaccines).

Alzheimer’s disease (AD) is the 6th cause of death in the US and affects over 3 millions Americans today with an expected increase to 13 millions by 2050. It is characterized by progressive memory loss and dementia. At the pathological level, AD is characterized by the formation of amyloid plaques and neurofibrillary tangles, such plaques are the aggregation of amyloid beta peptides 1-40 and 1-42, with oligomers considered the most toxic forms. We are still debating if these Abeta plaques are the cause of AD or if these plaques are a sort of defense mechanism against an infectious agent, which in turn drives neuronal cell death.

The problem in this claim is the following and you will see how this fallacious claim breaks as easily as a house of cards:

1) How does fluoride makes your body absorb extra aluminum? Aluminum is a metallic ion that cannot cross the cell membrane due to its positive charges (Al3+), therefore its entrance has to go through a paracellular (between cells) diffusion process. There is a study by Zhou and Yokel (http://www.ncbi.nlm.nih.gov/pubmed/15933224) that examined the impact of different aluminum forms on the intestinal barrier function in vitro. The only form that has shown some detrimental effect on the barrier function was aluminum fluoride (AlF3) but not ionized aluminum (Al3+). If you consider that fluoride makes your body absorb extra aluminum, it is…..if you are voluntarily ingesting AlF3. However, AlF3 is not the same than having Al3+ complexed by fluoride ions. An ionic bound is a non-covalent bound that easily breaks in a polar solvent like water. In the other hand the Al-F bounds are covalent bounds that are not broken that easily. Furthermore, fluoride is not transported per se in the body and compete with the same transporter than chloride. Because chloride surpass fluoride in terms of concentrations, there is little or no transport of fluoride, unless you are depleting yourself from chloride and overdosing on fluoride.

2) How does aluminum goes into your brain? Again, you should go and see my previous post on that aspect. The plasma level of aluminum is very low, about 1-3 ug/L (source: https://www.atsdr.cdc.gov/toxprofiles/tp22-c2.pdf). Again, the study by Zhou and Yokel show very little dietary aluminum (Al3+) entering the intestinal barrier. Since the intestinal barrier is as tight as the blood-brain barrier, the diffusion of Al3+ is negligible and cannot explain that second fallacious claim. However, we may consider an increase in brain aluminum content if we consider a disruption of the blood-brain barrier (BBB) due to other pathological disorders. In particular, there is a growing evidence that a disruption of the BBB in patients suffering from mild cognitive impairment (MCI), a condition preceding Alzheimer’s disease. So that second claim is not founded and makes sense only if you have a condition that impairs the BBB and might lead to an increase in aluminum penetration inside the brain.

3) Aluminum in the brains of AD patients? This claim is apparently based on epidemiological studies that have observed an increase incidence of AD cases in populations exposed to aluminum at occupational level. For this, I can refer to you to a recent meta-analysis paper by Wang and colleagues (http://www.ncbi.nlm.nih.gov/pubmed/26592479). This meta-analysis has shown an increased risk of AD in patients exposed to aluminum that was non-dietary (they failed to found an incidence between people consuming drinking water containing over 100ug/L  of aluminum versus those consuming drinking water with concentrations below), yet the limited number of studies and a direct assessment of exposure was limiting the power of this meta-analysis. This occupational exposure to aluminum can be variable, from miners extracting bauxite (aluminum ore) to aluminum foundries and any work involving aluminum pulverization or handling aluminum dust at any form. However, this is falling into the OSHA regulation as it is a manner of occupational safety. We can consider that exposure to aluminum dust should be handled by workers with a minimum personal protective equipment (PPE) including a respiratory mask (as the nasal cavity can provide a direct route for aluminum penetration inside the brain). More information on the regulation of aluminum exposure by the Department of Labor through their OSHA office can be found here (https://www.osha.gov/dts/chemicalsampling/data/CH_217980.html).

So you can see how by trying to tie different and distinct studies and observation, the author created a “post hoc ergo propter hoc” fallacy. He firstly assumed wrongly that AlF3 was equal to the ionized from Al3+ 3F-, that in fact is not true. Then he concluded that aluminum enters the BBB, yet there is not direct evidence and mechanism by which aluminum enters the brain or only enters the brain when concentration that 10-100 times the normal levels are applied. Finally, he wrongly concluded that because persons exposed to aluminum as part of the occupation had a higher chance of developing AD that aluminum was a irrefutable cause of AD.

Remember to always check the messenger credentials to firstly assess the validity of his message, then always check the current scientific literature to see the robustness of the claims made as well wether such claims are made of hot air or are made with a solid scientific consensus.

 

 

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2 thoughts on “[Junk Sciences] Fluoride, aluminium and the brain……when pseudosciences defies high-school chemistry

    • Absolutely. We need a “soft skill” training in science communication to the lay audience during the graduate training. I consider that indeed it should be part of the grant evaluation process in public funding. We all get funding from state and federal agency that at the end of the day comes from the average taxpayer. I believe we should as public-funded scientist have a moral obligation to give back to the community by sharing our science in the best PR we can. Otherwise, you get your science hijacked by snake oil sellers.

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