TCS Daily

The California AG Continues His Junk Science Crusade

By John Luik - November 2, 2005 12:00 AM

"The junk-food industry is peddling junk science."
-- Bill Lockyer, California Attorney General

Apparently stung by the criticisms about his junk science crusade against acrylamide, California Attorney General Bill Lockyer has come out swinging as only a trial lawyer turned politician can do -- by coupling a refusal to talk about the real scientific issue with a host of outright misrepresentations. Writing in the San Francisco Chronicle (October 17, 2005) Lockyer made the following claims:

        1) "Acrylamide is a potent cancer-causing chemical" ;

        2) "Acrylamide is found in certain kinds of potato chips and French fries at 
        levels 80 times over the healthy exposure limits" ;

        3) Instead of alerting consumers about high levels of acrylamide, some 
        food manufacturers "are concealing the facts: the junk-food industry 
        is peddling junk science."

So just what are the facts about acrylamide; or, more to the point, about Bill Lockyer's claims about acrylamide, for the two are not at all the same?

Lockyer claims that acrylamide is a "potent cancer-causing chemical". Now there are two quite extraordinary things about this claim: one is what it doesn't say and two is that even though it is his central argument, he provides no evidence to support it. First, notice what Lockyer is NOT saying. He isn't claiming that acrylamide causes cancer in human beings. Instead he is claiming that it causes cancer AND is found in human food. For the hurried reader or the inattentive listener, these come out as the same thing, but they are not. Acrylamide causes cancer and acrylamide causes human cancer through food are not at all the same thing.

The attorney general has conflated two quite separate points. The difference is crucial since as Elizabeth Whelan of the American Council on Science and Health has pointed out there is a difference between causing cancer and causing cancer in humans through their food. She writes that "If we were to label every food containing something that causes cancer in rodents, few foods would be spared."

There is evidence that acrylamide causes cancer in lab rats, but the risk is significant only at lifetime doses of 500 micrograms per kilogram of rat body weight, according to Joseph Levitt, Director of the FDA Center for Food Safety and Applied Nutrition. Assuming that one can extrapolate from rat risks to human risks, this means that a human would have to consume a lifetime daily dose of 35,000 milligrams of acrylamide to have the same cancer risk as a rat.

To get some idea of what this means, a person would have to eat about 180 pounds of French fries per day for life. Put differently, humans typically get a daily dose of acrylamide in their food that is 10,000 times less than that which gives cancer to rats. So, yes acrylamide causes cancer in lab rats, but only at extraordinarily high doses, doses that no human would encounter in his food.

And what about acrylamide and human, as opposed to rat cancer? Here the evidence is of two sorts, occupational exposures to acrylamide and food-based exposures. According to studies by Marsh et al (1999) there is not a statistically significant association between occupational exposure to acrylamide and cancer, a fact confirmed by the World Health Organization in its March report on acrylamide.

There are five major studies that have looked at the cancer risks from acrylamide in food. Four of these studies were done by Lorelei Mucci of Harvard. In her first study published in 2003 Mucci looked at dietary acrylamide and cancer of the large bowel, kidney and bladder and found no association between acrylamide and these cancers.

Similar results were found in a 2004 study by Mucci and others which looked for an association between acrylamide and the risk of renal cell cancer and which again found no link. In March, 2005 Mucci published a prospective study which examined whether there was a link between acrylamide and breast cancer. Once again there was no increased risk even for those subjects who ate the highest amounts of foods with acrylamide.

Finally, in July 2005, Mucci published another prospective study which looked at acrylamide and the risk of colorectal cancer and found that the "intake of specific food items with elevated acrylamide (e.g. coffee, crisp bread and fired potato products) was not associated with cancer risk."

Another study by Claudio Pelucchi of Milan in 2003 looked at acrylamide food intake and cancers of the oral cavity and pharynx, esophagus, larynx, large bowel, colon, rectum, breast and ovary and found no evidence of an association. In short, the scientific evidence about the cancer risks from dietary acrylamide all suggests that there is no association between foods that contain acrylamide and increased cancer risk.

But Lockyer also claims that acrylamide is "found in certain kinds of potato chips and French fries at levels 80 times over the healthy exposure limits." Again, this is an artful bit of junk science that manages to misrepresent the science both directly and through omission. First, there is, as Lockyer must surely know, no standard as to what constitutes a "healthy" acrylamide exposure limit in food. The EPA's standard, which he implicitly references, is for drinking water, not food.

Second and more importantly, we do have a good deal of real world scientific evidence about the carcinogenic risks of acrylamide in the very food Lockyer mentions, French fries. Recall that in Mucci's last study she specifically addressed the question of whether specific foods were associated with increased cancer risk and found that they weren't. She also found in her March 2005 study, that the major contributor of dietary acrylamide in her Swedish subjects was not French fries but coffee. Again, as the FDA has pointed out with respect to the US "no one food is contributing to the majority of the acrylamide."

As for Lockyer's claim about the "junk food industry peddling junk science" in an effort to avoid warning about acrylamide, on the basis of the science it appears that the industry doesn't want to warn about acrylamide because the foods it sells containing acrylamide are not causing cancer in humans. The nice thing about the record of scientific evidence about acrylamide and human cancer is that it is readily accessible and reasonably straightforward for anyone who wants to understand it. And that record also makes devastatingly clear that the real purveyor of acrylamide junk science is not the food industry but the Attorney General of California.

John Luik is writing a book on health policy.


TCS Daily Archives