By Robert W. Thurston
Why, given the hundreds of studies that show coffee is good for health, did a California judge rule that coffee must be labeled a carcinogen in that state?
The easy answer is that coffee contains acrylamide, a natural compound found in many cooked foods, and acrylamide can cause cancer. Because coffee companies have not displayed warnings about acrylamide, they may now be required to pay millions in fines, up to $2,500 per day since 1990. And coffee, after years of positive press, now must contend with a profoundly negative image; the South Koreans are looking into coffee and acrylamide, and the Europeans were already worried about the compound.
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For the most part, acrylamide arises during cooking, especially frying or grilling, from low concentrations of the amino acid asparagine and free sugars. Acrylamide has always existed in cooked foods and beverages, but it was not until 2002 that Swedish researchers identified it there. Acrylamide is a minor by-product of the Maillard browning reaction that occurs at high temperatures. A Maillard reaction takes place between amino acids and reducing sugars as they are heated. The reaction browns food and enhances flavor and aroma. Maillard reactions are an unavoidable part of roasting coffee beans.
Photo by Larry Kozimor
Propisition 65
A Prop 65 warning label on display in a Starbuckscoffee shop in Oakland, Calif.
The judge in California, Judge Elihu Berle, who is not a scientist, based his decision on science–or so it appears at first glance. But the problems, in this case, are manifold.
The law behind the case, Proposition 65 (Prop 65), formally known as the Safe Drinking Water and Toxic Enforcement Act of 1986, is sloppy. California has an environmental agency that lists substances found to cause cancer or reproductive harm. As of the end of 2017, the Prop 65 list ran to 22 pages. A few items identified by the state agency, for instance, tobacco smoke, are obvious.
Several common medicines are also on the list, among them Warfarin used to prevent the formation of blood clots and oral contraceptives. Thus the list is hardly an infallible guide to what anyone should ingest or avoid. Acrylamide appeared on the roll of harmful substances in 1990 as a carcinogen and again in 2011 as known to cause problems in human development and reproduction. In short, acrylamide, in sufficient quantities, can cause both cancer and disruptions in DNA. But then, swallowing 200 aspirin tablets at once will blow out your stomach. Quantity, or dosage, is often everything in medicine and diet.
Prop 65 opens a wide door for punitive suits. The law allows an individual or group, acting as a “private attorney general in the public interest,” to bring a case against specific companies for a judgment and damages regarding a specific product. Already the weight of the state is behind the complainers. As though the “trials” were criminal cases, “plaintiffs” charge that “defendants” have done wrong. In the coffee trial, Starbucks, Peet’s Coffee & Tea, and others, ultimately a total of 91 defendants, are named.
In a lawsuit over substance on Prop 65’s list, the burden of proof is entirely on the defendants to show that their product is not even remotely carcinogenic. They can first argue for “no significant risk level,” meaning that exposure to the amount of chemical in the product would result in no more than one case of cancer for every 100,000 individuals exposed to the chemical over seventy years. If that argument is rejected, defendants may argue that but a higher “alternative significant risk level” (ASRL) is justified if “sound considerations of public health support an alternative level.”
The California coffee trial began in 2010 when the non-profit Council for Education and Research on Toxics (CERT) filed in court against coffee companies for not providing cancer warnings on their products. CERT, which is really the Metzger Law Group, Ralph Metzger as lead attorney, started on litigation right away after the Swedish study became known. CERT has won a number of cases and large judgments, for example against numerous producers of potato chips.
The first phase of the coffee trial, decided in 2015, was largely about acrylamide itself. Despite testimony from well-known scientists and Starbucks’ objection that coffee contains many chemicals, Berle ruled that the defendants failed to document the harmless effects of acrylamide in isolation. He dismissed testimony that coffee lowered the risk of cancer as irrelevant.
The judge’s ruling against coffee last March, reaffirmed in May, was Phase II of the case. Phase III will be assignment of penalties. Only after that happens can any appeal proceed. Such appeals are almost never successful.
Berle’s decision disregards the World Health Organization’s (WHO) announcement in June 2016 that it “found no conclusive evidence for a carcinogenic effect of drinking coffee.” WHO drew upon work at the International Agency for Research on Cancer, which earlier had been quick to list substances as carcinogenic, for example, glyphosate, the active ingredient in RoundUp. That makes WHO’s announcement even more important.
In Phase II of the coffee trial, defendants tried to show that acrylamide in coffee had a low risk of causing cancer, that a lower ASRL was justified. Starbucks and other companies brought out big guns for the defense, including David Kessler, former head of the Food and Drug Administration. He argued that the risk pool should be no greater than 10,000, making the chance that an “excess” cancer would occur much less than in a population of 100,000. Lorenz Rhomberg also testified; he was responsible at the Environmental Protection Agency for working out formulas to extrapolate from results of laboratory tests on mice and rats in order to determine risk levels for humans. Various problems plague such extrapolations; the literature is filled with statements like “humans might show similar responses to equivalent [determined by body weight] chemical exposures.”
Berle refused to consider that, as Prop 65 allows, an ASRL does not apply when “chemicals in food are produced by cooking” to make the food palatable. Although some ideas about steaming, not roasting, green coffee are floating around, we all know that so far coffee beans must be roasted to be usable.
The judge found that Kessler’s testimony was not based on scientific evidence. Berle also declared that Rhomberg “did not calculate an ASRL for acrylamide in coffee by means of any quantitative cancer risk assessment.” Yet that is exactly Rhomberg’s specialty, and in fact he did calculate the quantitative risk. Material from Covance Laboratories, which specializes in chemical analysis of chemicals like acrylamide, was also not allowed. Thus Berle rejected the defendants’ ASRL argument. In fact, none of the testimony for the defense by highly regarded scientists was admitted in Phase I or II.
So the rats and mice won or died trying, in a certain sense. Since plaintiffs could point to lab studies that show those animals develop tumors when stuffed with huge amounts of lifetime acrylamide, those results trumped all else. True, coffee might cause some types of cancer in humans; yet, as many studies show, coffee helps prevent other types and overall does much more good than harm regarding cancer.
Berle’s decisions leave several questions unanswered: 1) what about the problems in extrapolating from rodent studies to humans? 2) Who could establish that one “excess” case of cancer among 100,000 people resulted from drinking coffee? 3) Why didn’t the well-documented finding that coffee reduces the risk of some cancers, as well as conferring other health benefits, outweigh the possible risk from coffee?
Bill Murray, president of the National Coffee Association, is worried that people are subject to a “barrage of information” every day that makes it likely some consumers will not look beyond warning labels. “We are in a post-factual world” where people rely on headlines, he noted to me. Nevertheless, Murray outlined three ways that the coffee industry can try to counter the California decision. At the state level, efforts are underway to persuade the legislature to amend Prop 65. Work within the state’s petition system might help, yet a successful drive would need to collect 500,000 signatures. Finally, there is the possibility that federal law, relying on the interstate commerce clause, could override California law. After all, packaging and even green and roasted coffee may come into the state from other states. Meanwhile, specific studies are looking into what exactly coffee’s effects are on human organs.
But after all this, Judge Berle’s decisions appear to indicate that the public’s fears about harmful food, evident as well in the Non-GMO Project and gluten-free labels, are growing. The coffee industry must hope that the steady stream of positive announcements about our drink and health will make an even stronger impression on consumers.
Robert W. Thurston, who holds a PhD in history, is author of Coffee: From Bean to Barista, to be published later this year.