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The FDA and WHO disagree over whether aspartame is a 'possible carcinogen'


The World Health Organization has classified aspartame as a possible - possible - carcinogen. Aspartame is an artificial sweetener which is used in everything from diet soda to yogurt to chewing gum. But U.S. authorities at the Food and Drug Administration stand behind its safety. NPR's Allison Aubrey reports.

ALLISON AUBREY, BYLINE: Aspartame has been around nearly 50 years, and the U.S. Food and Drug Administration has long maintained its safety. But recently, there have been a few studies pointing to a slight increase in cancer among people who consumed the highest amounts. The WHO's International Agency for Research on Cancer reviewed all the evidence and came to the conclusion that aspartame may possibly cause cancer, though they acknowledged the evidence was limited. Here's Francesco Branca, director of nutrition and food safety at the WHO. He spoke during a press conference in Geneva, Switzerland.


FRANCESCO BRANCA: Our results do not indicate that occasional consumption should pose a risk to most consumers. The problem is for high consumers.

AUBREY: The agency had long ago established an allowable daily intake of up to 40 milligrams of aspartame per kilogram of body weight. That amounts to something close to 12 Diet Cokes a day for a 130-pound person, and clearly most people don't consume that much. Dr. Branca says what they're suggesting is a bit of moderation, given the potential risks. He also points to a recent WHO analysis that found no clear long-term benefit of using nonsugar sweeteners to control weight.


BRANCA: If you want to curb your energy intake in the longer term, it doesn't help. So basically the benefit is not there.

AUBREY: The Food and Drug Administration has come out in defense of aspartame. An agency official says they disagree with the decision to classify it as a possible carcinogen, saying the artificial sweetener has been well studied and is safe. The agency said its own scientists reviewed the same studies the WHO reviewed and determined that these studies have significant shortcomings with inconsistent findings, and they say quite strongly they do not have safety concerns. They point out that some consumers may rely on products with aspartame to help reduce their sugar consumption. And Kevin Keane, interim president and CEO of the American Beverage Association, whose members include the Coca-Cola Company, PepsiCo and many other beverage manufacturers, say consumers should not be confused by the WHO classification.

KEVIN KEANE: Consumers should take all of this compendium of science, the overwhelming weight of the science, and be confident moving forward that aspartame is a safe choice.

AUBREY: Whether diet sodas help people manage body weight and limit sugar may vary from person to person. And when it comes to a potential cancer risk, Dr. William Dahut of the American Cancer Society says it's very clear that things like tobacco and obesity are linked to higher rates of cancer. But with aspartame, there's still unknowns.

WILLIAM DAHUT: The bottom line is that there is not current evidence that definitively leads ingestion of aspartame to cancer. However, since there is a possible link, it is certainly reasonable to limit one's intake until more definitive studies are available.

AUBREY: His group is calling for more research. In the meantime, the FDA says consumers should feel confident that aspartame consumed in moderation is safe.

Allison Aubrey, NPR News. Transcript provided by NPR, Copyright NPR.

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