Nanotechnology—the reduction of ingredients into nanometer-sized particles—has generated major buzz across myriad commercial industries over the past decade. Lauded for everything from their antimicrobial attributes to their superior sunscreening abilities, nanometer-sized versions of substances like silver, silica, titanium dioxide and zinc oxide, have mounting applications in the manufacture of food, supplements, personal care, pesticides and product packaging.
"There are thousands of commercial products available that employ nanoparticles in some measure," said Colin O'Neil, regulatory policy analyst for the Washington, D.C.-based Center for Food Safety. "They're being used throughout the food industry already, as antimicrobials on cutting boards and in food packaging. A package lined with a nano-sized antimicrobial like silver could allow lettuce to be shipped across the world with reduced risk of contamination. Nanomaterials can also change the color and pigment of materials. The food industry views them as the next level of industrial food processing and manufacture."
Despite their widespread use, the definition, characterization and regulation of nanoparticles by government bodies has been nebulous at best. Government agencies had previously defined nanos by size, but are now finding that chemicals and ingredients with entirely different characteristics shouldn't necessarily be lumped into one category based solely on particle dimensions. "CFS has been advocating against a one-size-fits-all definition of a nanoparticle," O'Neil said.
Besides ineffective classification, a more pressing issue is that many of these tiny particles take on properties and phenomena not seen in their larger counterparts--a crucial factor not initially considered by regulatory bodies. As a result, many of these nanoparticles evaded the usual safety testing that commercially used materials must endure, because particle size hadn't been seen as an issue.
But now it's becoming widely realized that size does indeed matter. "We have proof that nanoparticles are different from their bulk counterparts—that's no longer under debate," O'Neil said. "Now the question is how they'll be regulated."
FDA's new nanotechnology guidance
Last week the FDA issued a draft guidance that seeks to more accurately and adequately define nanoparticles and advise nano-using industries on how to employ them. In "Considering Whether an FDA-Regulated Product Involves the Application of Nanotechnology," the agency named characteristics—size and exhibited properties—to be considered when identifying nanoparticles' applications in regulated products.
As this guidance gains traction, it could significantly impact the development, release and use of new consumer and commerical products, such as deodorant that uses nano-sized silica and super-concentrated pesticides that use nano antimicrobials. Manufacturers may be subject to safety testing and guidelines surrounding nanoparticles that they hadn't been previously.
Common nanotechnology uses
One sphere that nanotechnology has infiltrated is dietary supplement formulation, because ingredients broken into nano-sized chunks can be more concentrated and bioavailable than larger particles. "Nanotechnology offers huge benefits," said Todd Runestad, editor-in-chief of Functional Ingredients magazine and the New Hope Supply Network. "Smaller doses can reach a target in the body more efficiently, which is a great perk."
Runestad offered the example of coenzyme Q10: "CoQ10 is a very popular and expensive ingredient, and there's always a biovailability issue," he said. "A handful of companies, all in China and Japan, produce the raw ingredient, and then after-market companies tweak it [by breaking it down into nano-sized particles] to make it more bioavailable. The result is consumers don't have to take as much—maybe only one pill—which saves them money."
However, the jury's still out over how the body reacts—and will be affected years later—to more efficient absorption of otherwise-beneficial nutrients. "Better and faster absorption isn't always a good thing," Runestad cautioned.
The nanotechnology and sunscreen controversy
Beyond supplements, one of the biggest consumer nanotech concerns surrounds the new spray-on titanium dioxide– and zinc oxide–based sunscreens, which coat skin evenly with ultraviolet-ray-blocking minerals without depositing that undesirable chalky-white film mineral blocks are known for.
"These sprays are so convenient, but titanium dioxide and zinc oxide are being absorbed into the body in a way they never have before," Runestad said.
So what is the concern? Clinical studies show that nano-sized titanium oxide and zinc oxide can be toxic to human skin cells and cause DNA damage when exposed to ultraviolet light, according to O'Neil. In addition, research shows that pregnant mice can pass titanium dioxide nanoparticles to offspring, which can cause nerve and genital damage; the miniscule particles have also lead to cancer in rodents. Whether these results translate into definite human risk is yet unknown, but experts have reason to believe they may.