Shaking up the nano-food debate

andrew.maynard@physics.org — Tue, 21 Oct 2008 21:39:00 GMT

First posted on 2020science.org, 20th October 2008:

Is the RBC Life Sciences® nanotechnology product Slim Shake approved for use by the US Food and Drug Administration (FDA)? According to the BBC Radio 4 science program Frontiers—broadcast on Monday evening—there may be some doubt. But I get ahead of myself.

The US-based company RBC Life Sciences® sells a range of dietary supplements and food products allegedly based on nanotechnology—8 of them are listed in the Project on Emerging Nanotechnologies public inventory of nanotech-enabled consumer products. As with many of the products in the inventory, it’s hard to tell whether they are truly using nanotechnology, and even harder to tell what steps have been made to assure their safety. But Monday’s edition of Frontiers shed a little light on this issue...

Monday’s program, called very simply “Nanofoods,” provided a thoughtful and balanced perspective on the development and use of nanotechnology in the UK food industry, and included interviews with representatives from the companies Unilever and Leatherhead Foods International, as well as the UK’s Institute for Food Research, the Central Science Laboratory and the Food Standards Agency.

Presenter Sue Broom started off looking into what nanotech can do for food—from futuristic drinks with dial-up flavours to low-fat mayonnaise that still manages to taste… well, tasty. But as the program progressed, the discussion gradually turned to the issue of safety. And when it got there, things began to get interesting.

Asked whether nanotech food additives that can be metabolized—i.e. broken down by the body—present a greater safety risk than their non-nano counterparts, most of the interviewees suggested that they probably did not. But Sandy Lawrie of the Food Standards Agency did caution that these assumptions really need to be tested in the laboratory.

However, when it came to nanoparticles that aren’t metabolized—nanoparticles that retain their particle-ness after being eaten and as they pass through the gut—there was less confidence that nanoscale ingredients could be assumed to be safe. Qasim Chaudhry from the UK’s Central Science Laboratory was particularly concerned about the possibility of such particles being transported to normally inaccessible parts of the body, and perhaps causing harm because of their small size and their durability. These concerns are echoed in a draft report on nano and food published by the European Food Safety Agency (EFSA) last week.

At this point, the RBC Life Sciences® product Slim Shake was introduced—to a backdrop of eerie music (OK, so I guess radio producers are allowed a little dramatic license in setting the sound-stage.). As explained by Kimberly Lloyd of RBC, the Slim Shake Chocolate contains “cocoa clusters”—individual particles of silica 4 – 6 nm in diameter, that are coated with the molecules responsible for giving chocolate its flavour. The high surface area of these nanoparticles supposedly gives an over-sized taste-hit when you drink the shake, which masks the taste of other ingredients in the drink (whatever they may be)—the point being that the Slim Shake tastes good without using too many of the ingredients that any self-respecting dieter would prefer to avoid.

The science actually makes sense, and RBC Life Sciences® should be applauded for actually coming out and explaining it. But there is a possible problem with those nanoscale silica particles—which are described on the program as being discrete particles, not aggregates. The folks producing Frontiers got in touch with the US Food and Drug Administration to see whether these silica nanoparticles were approved for use in Slim Shake. This is what they got back from the FDA:

“we are not aware of any tests that have been carried out to specifically demonstrate the safety of nanosized silica for this use. For those uses that FDA has determined to be safe, the silica is generally a fine powder but no lower limits on size exist other than those encompassed by good manufacturing practice.”

Mmm, so is RBC Life Sciences® using an unapproved food ingredient, or is life more complicated than this?

Amorphous silica has been used for decades as a food additive, and for specific applications it is Generally Regarded As Safe (a designation referred to as GRAS) by the FDA. But GRAS status depends on how a material is used, as well as what it is made of. And reading between the lines of the FDA statement, RBC have not established that their particular use of nano-silica as a food additive is GRAS; nor have FDA worked out whether existing determinations of silica safety apply to nanoscale forms of the material.

To be fair, much of the amorphous silica used in foods these days does have a nanostructure (the material Aerosil® is a good example). But it is typically used as large aggregates of nanoparticles—i.e. the resulting particles in the additive are much larger than the nanoparticles they are made up from. In contrast, RBC is claiming that their product contains individual nanoparticles—a departure that could alter the transport of the material within the body, and possibly its subsequent behavior.

Is it possible that RBC Life Sciences® think they are selling an FDA-approved product because of confusion over how existing regulations apply to nanomaterials? I shouldn’t speculate, but I would like to give them the benefit of the doubt. (It should also be noted that the company would be well within its rights to determine whether their nano-silica was GRAS without input from FDA—you don’t need prior FDA approval to put something like this on the market, but deciding to go it alone is often ill-advised.)

If this is the case, the faster guidance is developed by the FDA on how nanotechnology fits into existing regulations, the better. Because as Slim Shake seems to demonstrate, nanotech-enabled foods are appearing in the US that seem to be slipping through the regulatory net.

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Postscript (added on 21st October)

For an illuminating discussion on the UK Food Standards Agency response to Slim Shake in particular, and nanotechnology-based ingredients in food in general, fast forward to 23 minutes and 35 seconds into the Frontiers program - available on the web here.

Andrew Maynard : Food, Nanotechnology

Shaking up the nano-food debate