Issue Date: February 9, 2009
THE NUMBER of consumer products made with nanotechnology continues to grow at a rapid pace, particularly in the area of dietary supplements. As more of these nanotech-based supplements, or nanoceuticals, hit the market promising everything from better nutrient absorption to increased mental focus and creativity, consumer advocacy and watchdog groups are calling for increased government oversight to ensure that such products are safe and effective.
Dietary supplements are unique among nanotech-based products in that the potential for exposure to the nanoscale ingredients is extremely high. These supplements are meant to be sprayed inside the mouth or swallowed as a pill, capsule, or drink. Nanoceutical exposure "is very different than exposure from a tennis ball that has a nanoengineered clay liner," points out David Rejeski, director of the Washington, D.C.-based nonprofit Project on Emerging Nanotechnologies (PEN).
PEN tracks consumer products that claim to contain nanoscale substances. "We now have more than 800 consumer products in the inventory, which has doubled in the past 14 months," Rejeski says. When PEN started its inventory in March 2006, there were 11 dietary supplements. "Now we are up to 44," Rejeski notes.
Little information is available about nanoscale substances in dietary supplements because the Food & Drug Administration, which has regulatory authority over dietary supplements, has no mechanism to get information about these products, says William B. Schultz, an attorney with Zuckerman Spaeder. Schultz is the author of a recent PEN report that is highly critical of FDA's ability to regulate nanotech-based dietary supplements.
Several of the supplements claim to use nanoscale substances that encapsulate nutrients to increase their solubility and bioavailability. Many nutrients, such as polyphenols found in berries and tea, are crystals that are not readily bioavailable, says Qingrong Huang, an associate professor of food science at Rutgers University. "You need to break down the crystals to make them soluble in water," he points out.
Huang's research has focused on encapsulating flavonoids and carotenoids in dietary supplements using nanostructured emulsions. Such emulsions could be used to prevent nutrients from precipitating out of nutraceutical drinks, which contain natural extracts with physiological benefits, he says.
Getting more of a nutrient may sound like a good idea, but consumers need to be cautious, warns Carolyn N. Cairns, a program leader in product safety at Consumers Union, the publisher of Consumer Reports magazine. "A lot of these nutrients tend to have an upper limit on their toxicity. So something that is helpful or even critical at a given concentration can be toxic at a higher dose," she notes.
CONSUMERS HAVE no way of knowing whether a dietary supplement is safe or whether it does what it claims to do. Unlike a drug, which can't be introduced on the market until it is reviewed by FDA for safety and effectiveness, dietary supplements do not need FDA's approval before they are marketed. Under the 1994 Dietary Supplement Health & Education Act (DSHEA), "dietary supplements are regulated as foods and not as drugs unless there is a drug-treatment-type claim," Schultz notes.
Manufacturers of dietary supplements are responsible for ensuring the safety of their products before they are marketed. If the product is found to be unsafe after it hits the market, FDA is responsible for taking action against it.
Experts in the industry say that the regulatory framework provided by DSHEA is adequate to ensure the safety of dietary supplements. They point out that manufacturers must notify FDA at least 75 days prior to marketing a dietary supplement if it contains a new dietary ingredient.
But it is up to the manufacturer to determine whether a substance is a new dietary ingredient. "The statute really depends on the industry determining that the ingredient is new and giving notice to FDA. The company is free to determine that it is not new," and then the firm doesn't need to give notice to FDA, Schultz contends.
The underlying issue is how FDA defines a new dietary ingredient. According to the agency, a new substance is one that has not been previously marketed and has been chemically altered. Because nanoscale substances are not chemically altered???they are just substances reduced to the nanoscale through a physical process???it is unclear whether they should be considered new dietary ingredients. FDA has not spoken on the issue, Schultz notes.
Many people believe that FDA should consider nanoscale substances to be new dietary ingredients because they have novel properties. Silver, for example, behaves much differently in nanoscale form than it does in bulk form. "It all comes down to 'How do you define what is a new substance from a regulatory perspective?' " says Andrew Maynard, chief science adviser at PEN. "When the chemistry is the same but the functionality is different, how do you deal with that?"
Right now, without additional authority from Congress, one thing FDA could do is put out guidance for the industry declaring that nanoscale substances are new dietary ingredients, Schultz says. "It's always easier, in my experience, to write the rules and propose them at the beginning than it is after the fact. If FDA waits much longer, we are going to be faced with hundreds of products and hundreds of companies and a much more difficult situation," he warns.
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