[Catalist] Nanoparticles in Foods

[Leon Harris]

Hi Mike,
I'd be inclined to take a bit of a chill pill on this one.
“Titanium dioxide nanoparticles induce DNA damage and genetic 
instability in vivo in mice” looks like a classic kite-flying biology 
paper here.
The experiments were done with quite contrived anastase TiO2 particles, 
which are not the same as the rutile form used in food and paint 
products (they are a few hundred times more active). They used only 5 
mice per test, which is an unacceptably low number to generate any kind 
of meaningful data. The 8 hydroxy guanidine assay that those guys used 
is super sensitive to user error, and if not handled carefully can 
measure "degradation artifacts" in otherwise ordinary tissue. This 
means, that unless you have blinded the samples to the assayer, you have 
the potential for bias (not fraud, not malice, just wanting to believe). 
If the study is your PhD thesis, you have enough personally invested 
into it to have big bias issues.

This isn't to dismiss the value of this paper entirely. But science 
requires replication, and these findings aren't adequately replicated in 
the literature yet, despite having a couple of years to do so. I'd wait.

Many things cause oxidative damage to cells. We are the lucky survivors 
of the great oxygen catastrophe, some 3.2 billion years ago, and now 
cope with breathing a gas which is more reactive than chlorine, for 
breakfast. Early studies suggested something like 2% of electrons that 
flow through your mitochondria leak out and end up as free radical 
species (Irwin Fridovich was the author of that), although my old boss 
reckoned the proportion was much lower than that. Here's a possible 
scenario for you: If you are treating animals to different levels of 
TiO2 exposure, and you don't want them to eat each other's poo, you 
might house them in separate cages for separate dose rates. Well, at 
least the control ones, that shouldn't get to eat any TiO2. Illness 
causes a huge surge in oxidative damage, and chronic infection can be 
easily seen in 8-OH guanidine excretion in the urine. With most of the 
mice in one of the cages, you can see how the controls get a lower 
value.  Now I am not saying that this is what happened, but you can see 
how good-looking studies can get befouled with bias and artifacts. That 
is why we await some more detailed, larger, blinded and well controlled 
repetition before we get too excitable over one study.

Biological research is hard, arguably harder than a lot of the physical 
sciences, and full of confounding pitfalls, traps and uncontrollable 
variables. It is so easy to be blindsided by something that in 
retrospect seems obvious, but actually is unknowable at the time, owing 
to the complexity, history and well just mess of the systems involved.

By the way, at the doses of TiO2 fed to those mice, you wouldn't want to 
be eating tic-tacs while cleaning the cage! To mangle the advert a bit, 
getting distracted could lead to an un-cool surprise!


Cheers,
Leon

On 26/09/2015 3:50 PM, Michael McGarry wrote:
>
> Greetings Science Colleagues,
>
>
> Focus Question 1: Are the nanoparticles added to foods safe for human 
> consumption?
>
>
> “Big questions about risk assessment of nano materials"
>
>
> URL 1: 
> https://theconversation.com/big-questions-about-risk-assessment-of-nanomaterials-44835
>
>
> “Nanoparticles and nano safety: the big picture”
>
>
> URL 2: 
> https://theconversation.com/nanoparticles-and-nanosafety-the-big-picture-22061
>
>
> “Explainer: Nanotechnology and you”
>
>
> URL 3: https://theconversation.com/explainer-nanotechnology-and-you-743
>
>
> “Titanium Dioxide Nanoparticles in Food and Personal Care Products”
>
>
> URL 4: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3288463/
>
>
> “Titanium dioxide nanoparticles induce DNA damage and genetic 
> instability in vivo in mice”
>
>
> URL 5: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3873219/
>
>
> Focus Question 2: Does existing Australian federal government 
> legislation/regulation require the labelling of foods that contain 
> added nanoparticles?
>
>
> “Nano material Health Hazard Review: Health effects of titanium 
> dioxide nanoparticles”
>
>
> URL 6: 
> http://www.nicnas.gov.au/communications/issues/nanomaterials-nanotechnology/nicnas-technical-activities-in-nanomaterials/nano-titanium-dioxide-human-health-hazard-review/nano-titanium-dioxide-technical-information-sheet
>
>
> “Contemporary and Future Challenges for Australian Nano regulation”
>
>
> URL 7: 
> https://law.anu.edu.au/sites/all/files/users/u9705219/236-ssrn-nanoreg_in_aust.pdf
>
>
> A Request to Science colleagues:
>
>
> Important Question: Do you have a list of specific foods and the added 
> nanoparticles that these listed-foods contain so that I can exclude 
> such foods from my diet?
>
>
> Thanks and Best Wishes,
>
>
> Mike McGarry
>
>
>
> _______________________________________________
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