Illustration: Gary Taxali
If the specter of
obesity and
diabetes wasn't enough to turn you off
high-fructose corn syrup (HFCS), try this: New research suggests that the sweetener could be tainted with
mercury, putting millions of children at risk for developmental problems.
In 2004, Renee Dufault, an environmental health researcher at the
Food and Drug Administration (FDA),
stumbled upon an obscure Environmental Protection Agency report on
chemical plants' mercury emissions. Some chemical companies, she
learned, make lye by pumping salt through large vats of mercury. Since
lye is a key ingredient in making HFCS (it's used to separate corn
starch from the kernel), Dufault wondered if mercury might be getting
into the ubiquitous sweetener that makes up 1 out of every 10 calories
Americans eat.
Dufault sent HFCS
samples from three manufacturers that used lye to labs at the University
of California-Davis and the National Institute of Standards and
Technology. The labs found mercury in most of the samples. In September
2005, Dufault presented her findings to the FDA's center for food
safety. She was surprised by what happened next. "I was instructed not
to do any more investigation," she recalls. FDA spokeswoman Stephanie
Kwisnek says that the agency decided against further investigation
because it wasn't convinced "that there was any evidence of a risk."
At first, Dufault was reluctant to pursue the matter. But eventually,
she became frustrated enough to try to publish the findings herself.
She had her 20 original samples retested; mercury was found in nearly
half of them. In January, Dufault and her coauthors—eight scientists
from various universities and medical centers—published the findings in
the peer-reviewed journal
Environmental Health. Although they
weren't able to determine what type of mercury was present, they
concluded that if it was organic, the most dangerous form, then based on
average HFCS consumption, individuals could be ingesting as much as 200
micrograms of the neurotoxin per week—three times more than the amount
the FDA deems safe for children, pregnant women, women who plan to
become pregnant, and nursing mothers.
But the FDA and the Corn Refiners Association, an industry trade
group, claim there's nothing to worry about. The group hired ChemRisk,
the consulting firm whose scientists testified on behalf of a polluting
utility in the lawsuit portrayed in
Erin Brockovich, to analyze
Dufault's report. ChemRisk criticized Dufault for not specifying the
type of mercury her tests had found. This, the consultants said, was
key, since mercury poses different risks depending on its chemical form.
In its unadulterated elemental state, mercury is relatively safe to
ingest—the body absorbs only about a tenth of a percent of it. Inorganic
forms of mercury, such as cinnabar, are more easily absorbed and
therefore more dangerous than elemental. Organic forms, like
methylmercury, which originate from
fossil-fuel
emissions and build up in the fatty tissue of tuna and other kinds of
fish, are the worst; readily absorbed, they can cumulatively damage the
brain and nervous system.
Though it provides no scientific evidence to back up this assertion,
the FDA says that the mercury in Dufault's HFCS samples is elemental.
But the lab that analyzed the samples believes there's a good chance the
mercury is
organic.
The analysts "said in so many words, 'It doesn't look like inorganic,'"
says Peter Green, Dufault's UC-Davis colleague who coordinated with the
lab. "They would even say it's more likely not the regular elemental
mercury."
The corn-syrup industry claims that no HFCS manufacturers currently
use mercury-grade lye, though it concedes some used to. (According to
the EPA, four plants still use the technology.) It says that its own
tests found no traces of mercury in HFCS samples from US manufacturers,
including a number of samples from some of the same sources Dufault
tested. But hundreds of foreign plants still use mercury to make
lye—which may then be used to make foods for export. Already, 11 percent
of the sweeteners and candy on the US market are imported.
At around the same time that she published her study, Dufault also
learned of a report issued by the Minnesota-based Institute for
Agriculture and Trade Policy, which found low levels of mercury in 16
common food products, including certain brands of kid-favored foods,
like grape jelly and chocolate milk. Researchers haven't proven that the
mercury in the foods came from HFCS, but internist Jane Hightower, who
coauthored the
Environmental Health study, points out that it
ultimately doesn't matter how it got there: The FDA has allegedly known
about the mercury-contaminated hfcs for nearly four years and "should
already have an answer for us based on science and not speculation," she
says. The agency says it has no plans for further testing unless
additional evidence of harm emerges in outside scientific literature.
But the issue has been getting some attention in Congress—a bill
proposed in April would require plants that once employed the technology
to report how much mercury they used.
Dufault retired from the FDA in January 2008, after the agency began
taking her off her field projects. "All of a sudden, they wanted me to
sit in the office," she says. She moved to Hawaii, but she hasn't
exactly been lounging on the beach. She recently finished a paper,
currently in the peer-review process, that explores why children and
fetuses are more sensitive to mercury than adults. She also teaches
second- and third-graders with learning disabilities. "I worked for an
organization that allowed stuff to go on that probably impacted these
children," she says. "I look at this as doing penance."
