Does the Acrylamide in Coffee Cause Cancer?

Check out this answer from Consensus:

The current body of evidence suggests that while acrylamide is a probable human carcinogen, the levels of acrylamide typically consumed through coffee do not significantly increase cancer risk. Epidemiological studies have generally found no strong association between acrylamide intake from coffee and various types of cancer, including endometrial, ovarian, breast, colorectal, prostate, and renal cell cancers. However, further research is needed to fully understand the potential health risks of acrylamide and to provide more definitive guidance on safe consumption levels.

Acrylamide is a chemical compound that forms in certain foods during high-temperature cooking processes, such as frying, roasting, and baking. Coffee is one of the common dietary sources of acrylamide. Given its classification as a probable human carcinogen by the International Agency for Research on Cancer (IARC), there is significant concern about the potential cancer risk associated with acrylamide intake from coffee. This article reviews the current scientific evidence on the relationship between acrylamide in coffee and cancer risk.

Acrylamide and Its Formation in Coffee

Acrylamide is formed in coffee during the roasting process. The levels of acrylamide in coffee can vary depending on the roasting conditions and the type of coffee beans used. Studies have shown that the acrylamide content in coffee brews from vending machines ranges from 7.7 to 40.0 µg/L, with an average of 20.6 µg/L6. Despite these levels, the overall exposure to acrylamide from coffee consumption is relatively low compared to other dietary sources.

Epidemiological Evidence

General Cancer Risk

Several epidemiological studies have investigated the association between dietary acrylamide intake and cancer risk. A systematic review of human epidemiological studies found mixed results, with some studies indicating a positive relationship between acrylamide exposure and cancer risk, while many others did not find a significant association1. This inconsistency suggests that more comprehensive studies are needed to draw definitive conclusions.

Specific Cancer Types

Endometrial and Ovarian Cancer

A meta-analysis and a prospective cohort study in Japanese women found no significant association between dietary acrylamide intake and the risk of endometrial or ovarian cancer after adjusting for coffee consumption3 7. These findings suggest that acrylamide intake from coffee may not significantly impact the risk of these cancers.

Breast Cancer

The relationship between acrylamide intake and breast cancer risk appears to be complex. A systematic review and dose-response meta-analysis found little to no association between acrylamide intake and breast cancer risk, except for a slight increase in risk among premenopausal women with high acrylamide intake7.

Colorectal Cancer

A large prospective study in Swedish women found no evidence that dietary acrylamide intake, including from coffee, is associated with an increased risk of colorectal cancer8. This study highlights the importance of considering specific food items and their acrylamide content when assessing cancer risk.

Prostate Cancer

Research on the association between acrylamide intake and prostate cancer has also yielded null results. A large prospective cohort study in the United States found no significant association between dietary acrylamide intake and the risk of prostate cancer, including advanced or lethal forms of the disease9.

Renal Cell Cancer

A case-control study in Sweden found no association between dietary acrylamide intake and the risk of renal cell cancer10. This study supports the findings of previous research, suggesting that acrylamide intake from coffee and other foods does not significantly impact renal cell cancer risk.

Mechanistic Studies

Animal studies have shown that acrylamide can cause cancer in rodents at high doses, but these doses are much higher than those typically consumed by humans through diet2 4. The carcinogenic effects observed in rodents are species-specific, and it remains unclear whether these results can be directly extrapolated to humans5.

Does the acrylamide in coffee cause cancer?

Simon Baker has answered Unlikely

An expert from University of York in Bladder Cancer

In 2018 a California judge ruled that Starbucks and other coffee companies in the state must serve the drink with a cancer warning. The legal issue comes from the presence of acrylamide in coffee. This chemical is typically found in many foods with a high carbohydrate content that are exposed to high temperatures, including cakes, potato crisps, bread and cereals. Evidence shows that acrylamide is probably a human carcinogen, a cancer-causing substance.

The acrylamide in coffee is formed early in the roasting process, which turns the fresh green beans the dark brown colour we are familiar with and gives coffee its deep bitter flavour. Once inside the body, acrylamide can be converted to another compound, epoxide glycidamide, and both of these chemicals can bind to and damage our proteins and DNA. Damage to DNA can be the first step in the development of cancer, and acrylamide also interferes with DNA repair.

The problem with the recent court ruling was that person bringing the case only needed to show there were trace amounts of acrylamide in coffee in order to succeed. This is where the reality of our lifestyles makes the ruling seem over-cautious.

Nobody disputes that coffee contains acrylamide or that acrylamide causes DNA damage, but it’s how much you consume that is important. The risk is really related to the total sum of exposure over a lifetime, but one estimate suggests an 80kg adult consuming less than 208 micrograms of acrylamide a day should not have any increased risk of cancer.

The main lifestyle choice that exposes people to toxins is smoking. Each cigarette contains around 2.3 micrograms of acrylamide, among a cocktail of other carcinogens. But all the foods we roast or fry to get delicious caramelisation also contain acrylamide. So non-smokers’ lifestyles are not acrylamide-free, with 5 micrograms in a slice of toast or 7 micrograms in a bag of potato crisps, as examples.

A cup of coffee fits into our daily acrylamide exposure at around 0.9 micrograms to 2.4 micrograms per 150 millilitre cup. But every cup also contains a diverse array of anti-oxidants and other compounds thought to have positive health effects (outside of pregnancy).

The same group of scientists (working for the World Health Organisation), who classified acrylamide as probably carcinogenic, found there was no conclusive evidence that drinking coffee caused cancer. In fact, they suggested coffee drinking may protect against liver and endometrial cancers and more recent studies have supported this idea. In 2016, the WHO took coffee off its list of possible carcinogens.

Scientists’ original concern over coffee drinking followed studies that suggested a possible link with bladder cancer. But closer analysis of the data and larger scale studies showed that the original research was confused by not taking account of smoking habits. It’s possible that coffee drinking interacts with smoke carcinogens to increase the risk of bladder cancer for smokers. In non-smokers, there is no robust evidence of a link between coffee and bladder cancer.

If you’re still worried about the acrylamide in coffee, it’s worth noting that less acrylamide seems to make it into the cup when the coffee is filtered than made using the espresso method. The choice of beans and roasting time might be important too since Robusta contains more acrylamide than Arabica, and darker roasts contain less than lighter ones.

Verdict

Acrylamide isn’t good for you but the amount present in coffee makes no observable contribution to cancer risk. There is no strong evidence for a link between drinking coffee and developing cancer. While there have been occasional studies suggesting an increased risk in bladder cancer, overall the vast majority of rigorous studies suggest that if coffee drinking has any effect at all it actually offers a mild protective effect from some cancer types.

I have adapted this answer from my original article in The Conversation