APR 02, 2018 7:00 AM PDT

Judge Rules that Cancer Warning Labels for Coffee are Needed in California

WRITTEN BY: Mauri Brueggeman

Coffee and cancer have been in the news lately; the focus is on a California (CA) Judge who, on March 28, 2018, delivered his ruling on a case that was originally presented in 2008 on behalf of a CA based non-profit group concerned with research and education around the toxicity of chemicals.  This is a little like that game “Which one is not like the others…” where coffee, coffee beans, bean roasting chemistry, and human cancers are grouped together.  The ruling went against coffee shops which may force them to place a cancer warning label on their coffee products to meet CA requirements.

The state of CA’s Safe Drinking Water and Toxic Enforcement Act requires that companies with more than 10 employees warn consumers about the potential risks of their products which may contain carcinogenic and toxic chemicals.  In and of itself, this does not seem to be complex.  However, this case has been in litigation for a decade.  The debate revolves around the chemical compound acrylamide.  According to the National Institute of Environmental Health Sciences (NIEHS), human exposure sources to acrylamide are most commonly from food and cigarette smoke.

Acrylamide structure; Photo Source: The Metabolomics Innovation Centre

Acrylamide is what scientists use for electrophoresis and chromatography matrices, as well as in electron microscopy, paper making operations, and water treatment facilities.  It is a crystalline amide that pharmacologically speaking, is considered reproductively and neurologically toxic, as well as being a carcinogen in animal species.  Acrylamide forms in food as a byproduct, called the Maillard reaction between amino acids and reducing sugars; when foods are heated to high temperatures (>338 degrees Fahrenheit; >170 degrees Celsius) that “browning” effect during roasting or “charring” of foods occurs. It was discovered in 2002 by scientists in Sweden but has likely been present for as long as food has been baked, fried or roasted.  The Food and Drug Administration (FDA) looked to the National Toxicology Program (NTP), a government program within the U.S. Department of Health and Human Services, to conduct research into acrylamide risks to humans and animals; previous studies had shown acrylamide to be a causative agent of several cancer types in animals.  Their two-year study results reported evidence of carcinogenic activity in rats and mice.  According to the NTP, tumors were found in mammary and thyroid glands in female rats and in the reproductive organs in male rats.  Lung tumors developed in mice studied. 

Alternatively, others have published research indicating the cancer preventative benefits of consuming coffee, mainly believed to be due to the antioxidants found in coffee.  Of interest, those touted antioxidants are produced as part of the roasting process of coffee beans.  The World Health Organization Working Group evaluated 1000+ studies in humans and animals and concluded that there was inadequate evidence for the carcinogenicity of coffee drinking overall and changed the 1991 classification of coffee as “possibly carcinogenic to humans (Group 2B)” to “not classifiable as to its carcinogenicity to humans (Group 3)” in 2016.

Acrylamide levels found in natural coffee differ based on the roasting process; the highest levels of acrylamide are formed early during the roasting process and drop significantly near the end of roasting, therefore the darker the roast, the lower the level of acrylamide.  In terms of coffee products, the highest amounts of acrylamide have been reported to be in coffee substitutes and instant coffees.  The International Agency for Research on Cancer have said that acrylamide is “possibly carcinogenic to humans.”  There are currently only a few measures available for acrylamide mitigation in coffee.  The FDA has also reported that the levels of acrylamide found in coffee will decline during longer term storage, but more research is needed to make specific recommendations about shelving your coffee beans in the cabinet for a period of time prior to percolation.  Additional permutations of this topic include the types of beans used and the differing methods used in coffee preparation which affect the amount of grounds that remain present in the coffee solution (French press, espresso, etc. vs. brewed). 

Commonly known coffee bean products (prior to brewing) can have between 50 and 200 parts per billion (ppb) of acrylamide present.  After brewing, these amounts are reduced by nearly 95% on average to between 5 and 15 ppb per cup.  The federal limit for acrylamide in drinking water is 0.5 ppb, or about 0.12 micrograms (ug) in 8 ounces of water.  An 8 ounce cup of brewed Starbucks coffee has close to 9 ppb acrylamide, or 2.1 ug.  For comparison, Cheerios was shown to have 266 ppb and lightly salted Kettle brand potato chips come in at 1,265 ppb.  Depending on dietary intake choices, an individual’s acrylamide exposure from daily coffee over a few weeks would be less than if that same individual consumed one bag of potato chips.  Broadly, the studies finding that acrylamide increases the risk of cancers have used doses of acrylamide as much as 1,000 to 10,000 times higher than the levels people might be exposed to in food.

The complexity of cancer, or tumor development, involves many more factors; estimating potential risks related to diet exposure remain elusive due the multitude of confounding factors and individual unknowns involved, including but not limited to: genetics, environment, and lifestyle.  These factors affect most, if not all, types of cancers in some way. 

There isn’t a dispute that acrylamide exposure could be a risk factor for cancer development, but the data provided so far for singling out coffee as a focus is weak.  Cancer causation and development is far more complex.

Sources: National Institute of Environmental Health Sciences, National Toxicology Program, Agency for Toxic Substances & Disease Registry, National Center for Biotechnology Information-Open Chemistry Database, International Journal of Food Science, Acrylamide in Food, SuperfoodlyAssociated Press, Roast Magazine

About the Author
Master's (MA/MS/Other)
Mauri S. Brueggeman is a Medical Laboratory Scientist and Educator with a background in Cytogenetics and a Masters in Education from the University of Minnesota. She has worked in the clinical laboratory, taught at the University of Minnesota, and been in post secondary healthcare education administration. She is passionate about advances and leadership in science, medicine, and education.
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