The Physics Police

The Physics Police

Tuesday, October 1, 2013

Titanium Dioxide

The motto of the shock blog Green Med Info is "education equals empowerment". Its founder, Sayer Ji (one of the worst human beings alive), has a degree in Philosophy with a specialty in existential phenomenology. Naturally, this makes him an expert in the study of molecular biology. Did I say expert? I meant dangerous know-nothing.

In a recent post, he asks the villainous and leading question Why Is The Food Industry Poisoning Us With Trillions of Nanoparticles?

The short answer is, of course, they're doing no such thing!

The nanoparticles in question are titanium dioxide, a white pigment used as a food additive. These particles are manufactured using chemical processes from rocks called ilmenite and rutile.

Nanotechnology is not involved in their manufacture. However, the resulting molecules are small. Normal people call that a "powder" but I guess you can call them "nanoparticles" because many are 100 nanometers in size.

Of course, lots of things we eat are less than 100 nanometers in size. When you caramelize sugars with heat, for example, carbon nanoparticles are produced. Is the food industry poisoning us with grilled onions and caramel candy? Other nanoparticles commonly found in nature include water ice in clouds, smoke from a fire, volcanic ash, ocean spray, fine sand and dust, and even viruses.

Clearly, particle size alone is no way to evaluate food safety.

Let's take a look at the science.

The recent study cited in this post is titled Effects of titanium dioxide nanoparticles in human gastric epithelial cells in vitro, and was published by a Portuguese team in the journal Biomedicine & Pharmacotherapy.
Our results demonstrate for the first time that nanoparticles induce tumor-like phenotypes in human gastric epithelial cells.
As the title suggests, it examined the effect of titanium dioxide nanoparticles on cell lines taken from human stomach lining, which are a specialized type of skin cells. The "tumor-like phenotypes" observed were DNA damage, oxidative stress, and increased cell proliferation. Sounds scary, right?
 Well, don't worry. These results are completely irrelevant to dietary sources! There are two major differences between the form of titanium dioxide that makes white pigment used in foods, and the stuff exposed to in this study.

First, the nanoparticles used in this study are engineered, industrial grade particles smaller than 25 nanometers, and have regular geometric shapes. The food additive particles are largely around 100 nanometers, and have irregular shapes. The biological action of these two, very different products are not comparable.

Second, the concentrations of nanoparticles in the study are ludicrously high. DNA damage and oxidative stress were seen only at a 15% solution. That's a really high concentration, environmentally unrealistic when compared with the 0.1% concentration in many whitened food products. Some products have much less, like Nestle Original Coffee Creamer, for example, which only has 0.004% titanium dioxide.

Cell proliferation, on the other hand, became significant around 6%.

Still, we know that oxidative stress, DNA damage, increased cell proliferation are involved in the formation of cancer, right? So, does this study show that high concentrations of engineered titanium dioxide nanoparticles are a carcinogen?

No. Here's the problem with that interpretation. The study used AGS cells, which are line of human stomach cancer cells. Yes, cancer cells. (Remind you of Séralini?)

To attribute the "tumor-like phenotype" of these cancer cells to the act of drowning them in white pigment is just ridiculous!

They were cancer before you painted them white!

In my opinion, the cell proliferation is easily explained by the oxidative stress. This is a well known phenomena, and makes sense for tissues that need to quickly regrow after being damaged. The stomach lining exactly fits that bill. Except, in this example, since titanium is so easily chelated, cell death is minimal. This results in a weird situation for these cells, indeed.

Consider, though, how contrived is this experiment. Results relied on nanoparticles of just the right size (25 nanometers) and shape (Degussa showed dose-response, Sigma did not). Statistically significant results were seen only at extremely high concentrations (6% solution).

Sounds like a lot of fine-tuning, doesn't it? Wait, there's more!

The team's first attempt failed to find increased cell proliferation:
First, we used RPMI supplemented with FBS for the suspension of TiO2 nanoparticles. This treatment caused no alteration on cell proliferation. These results are explained by the effect of the protein adsorption ability of metal oxide nanoparticles on the cytotoxicity.
FBS stands for fetal bovine serum. Basically, this is the food they used to wake up the starved cells, so they would keep growing. When they performed the experiment the first time around, the presence of proteins in the FBS prevented the nanoparticles from causing cell damage.

These proteins seem to be sticky to the nanoparticles used. They act like sponges, having a tenancy to round up nanoparticles. Like a sort of molecular lint roller, this seems to have been enough to prevent any significant damage to the cells.

Consider that, inside your gut, there are a lot of proteins and other potentially sticky things, like bacteria. After all, it's pretty messy in there! This same protective effect would likely keep your cells from absorbing too much titanium, even if you chugged a tall glass of white paint.

Consider, also, that your gut epithelium is a type of tissue called a mucous membrane. It secretes a mucus made up of, among other things, mucin proteins. These presumably act as an effective barrier protecting the stomach lining from damage due to ingested nanoparticles.

After all, evolution has adapted the gut to handle nanoparticles from ingested dust, dust, soot, and dissolved metal oxides in water.

Nanotechnology is new, and its development and use should be performed cautiously, especially when human exposure is possible.

Let's not get distracted by fear mongers like Sayer Ji, frantically grasping at straws in order to push their anti-science, anti-medicine agenda.

Titanium dioxide is far better than the zinc- and lead-based pigments it replaces.

In reasonable quantities, it's safe to ingest, just like iron oxide, or any other trace mineral.

Before I end this post, I want to share one more funny story involving titanium nanoparticles.

Rightfully published in the "rumors" section of MSN News is an article by Sally Deneen titled Toxic nanoparticles are entering the food supply. The article includes this tangled paragraph:
Titanium dioxide, a common additive in kid-tempting candies, marshmallows, icing and more, says this study, was found in recent studies to inflame rats' lungs when non-food-grade nano-sized titanium dioxide is inhaled, Kavanagh said. Whether eating it causes problems is being investigated in animal studies, he said, all of which tend to use high doses.
As the article disclaims, this study, too, uses engineered titanium dioxide particles, less than 25 nanometers in size, administered in high doses. At least, for the sake of relevance, it's performed on mammals, not cancer cells.

Of course the article does get everything else wrong. The results were negative for rats. It was the lungs of mice, not rats, where an effect was identified. Also, inflammation was not directly measured, but inferred from the ratio of neutrophils to other types of white blood cells.

In this study, too, we see the same shady pattern, where they didn't get desired results, so they tuned the experiment to fit their preconceived conclusion:
The first round of in vivo studies involved three independent labs, all of which used SD rats that were exposed to either TiO2-P25 or TiO2-A in DM. None of the treatment groups reported statistically significant changes in lung inflammatory parameters relative to DM controls; therefore, the scope of the consortium studies was expanded to include another rat strain (F344) and another species (mouse, C57BL6).
Rats didn't work? Let's try more, different rats. Oh, and mice too. Because, why not, right?

Three different doses were administered to the poor mice, 10, 20, or 40 micrograms. This was mixed with 100% ethanol and sprayed into their lungs. Sorry, mice. A statistically significant raise in neutrophils was only seen at the highest dose.

For fun, let's scale up this dose proportionately from a 25 gram mouse to a 75 kg human.

How much Nestle Original Coffee Creamer would I have to inhale, to inflame my lungs?

((40 µg / 25 g) * (75 kg)) / ((0.04 µg/mg) * (1,000 kg/m³)) = 3 Liters

That's a lot of coffee creamer to snort!

Don't try this at home.

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