I ’ve been voicing concern about the growing use of nanomaterials (particles so small they can be a millionth of a millimeter in width) for several years now... meanwhile, their use continues to be expanded in spite of a lack of research into product safety. (See Daily Health News, October 23, 2008, for more information on nanoparticle safety concerns.) The latest application? Dietary supplements. I find this particularly ironic since the reason people take them is to improve health.

A recent report in the journal Chemical & Engineering News brought attention to "nanoceuticals," as they’re sometimes called, or dietary supplements made with nanosized materials, which apparently are thought to improve nutrient absorption. The non-profit Washington, DC-based Project on Emerging Nanotechnologies knows of at least 43 supplements containing nanoparticles today. These products aren’t big sellers and they represent only a "nanofraction" of the thousands of supplements available, but the number is about four times greater than just three years ago. Clearly there is a trend toward growth in this questionable direction.

I checked in with Andrew Maynard, PhD, chief science advisor at Project on Emerging Nanotechnologies and a trusted source on this topic. He agreed that this is cause for concern, saying it is a development the FDA should focus on more. Though there are no known adverse health effects related to nanoparticles, "there’s no oversight that ensures that any nanomaterials used in these products are safe, either -- and, in particular, there is a worrying lack of long-term safety data." While many are urging the need for safety studies, dietary supplements don’t require pre-market approval from the FDA and every previous attempt to change that ruling has failed.

In the meantime, what’s a consumer to do? Since there are no labeling requirements, you can’t rely on the ingredient list to identify products made with nanoparticles -- but you can check out the Project on Emerging Nanotechnologies database (www.nanotechproject.org) to see whether a product you take contains them. Don’t be alarmed if you discover you are taking such a product -- it’s not an emergency, but it is something to be aware of and perhaps a reason to consider alternative products. "Nobody should panic," Dr. Maynard says, "but this is definitely a case of 'buyer beware.' "