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In 2023, Canada imported 30 per cent of its coffee from the U.S., 12 per cent from Switzerland and 3.5 per cent from Italy.iStockPhoto / Getty Images

If you enjoy the taste of coffee but don’t want caffeine’s side effects, decaffeinated coffee with 97 per cent of the stimulant removed is an alternative for your morning brew.

Recent new stories, however, may have left you concerned about the safety of decaf coffee.

Health advocacy groups in the U.S. recently petitioned the U.S. Food and Drug Administration (FDA) to ban the use of methylene chloride in the decaffeination process owing to cancer concerns.

Here’s an explainer about methylene chloride, where Health Canada stands on the chemical, plus tips on how to avoid it when opting for decaf.

What is methylene chloride?

Methylene chloride (also called dichloromethane) is a colourless synthetic chemical that’s used as a solvent in paint and furniture stripping products and a component in aerosol products and other industrial applications.

When it comes to food, methylene chloride is used as a solvent to remove caffeine from coffee beans and tea leaves.

There are several ways to remove caffeine from coffee beans. The most common of those, called the direct method or the European method, involves steaming green unroasted coffee beans to open their pores and make caffeine accessible. The beans are then rinsed with methylene chloride or ethyl acetate to extract the caffeine. Once the caffeine is removed, the beans are washed, dried and roasted.

Methylene chloride is used predominantly in Europe. According to data from the U.S. International Trade Commission, the top source of decaffeinated coffee beans in the U.S. is Germany, followed by Italy and Switzerland.

In 2023, Canada imported 30 per cent of its coffee from the U.S., 12 per cent from Switzerland and 3.5 per cent from Italy.

Methylene chloride is also used to process spices and create extracts used as food ingredients, including hops extract for beer.

Health risks of methylene chloride

When inhaled, methylene chloride can cause wheezing, shortness of breath, headaches, dizziness, nausea and memory loss.

Exposure to high levels of the chemical can cause serious harms to health, even death.

Owing to its toxicity, in 2019 the U.S. Environmental Protection Agency banned the chemical from being manufactured and sold as a paint remover.

In 2023, the agency proposed a ban on all consumer uses and most industrial and commercial uses of methylene chloride.

Animal studies have demonstrated that inhaling methylene chloride causes liver and lung cancer.

As such, methylene chloride is classified as a Group 2A probable carcinogen to humans by the International Agency for Research on Cancer, an agency of the World Health Organization.

This means there is strong evidence that methylene chloride can cause cancer in humans, but at present it’s not conclusive.

What about methylene chloride in decaf coffee?

Both the Canadian and U.S. governments strictly limit residues of methylene chloride to no more than 10 parts per million (0.001 per cent) in decaffeinated roasted coffee beans, decaffeinated instant coffee and decaffeinated tea leaves.

According to Health Canada, data indicate actual levels of methylene chloride in dry decaffeinated coffee (and tea) are much lower than the permitted limit.

What’s more, the amount in coffee and tea will be even less when hot water is used to make the beverages since methylene chloride vaporizes at a temperature of 40 degrees Celsius. (Boiling water is 100 degrees Celsius.)

There is no evidence that drinking coffee that’s been decaffeinated using the European Method poses health risks.

Rather, many studies have linked drinking decaf (and regular) coffee every day – compared to not drinking coffee – with a lower risk of type 2 diabetes and all-cause mortality.

Current petition to ban methylene chloride

Last November, the U.S.-based Environmental Defense Fund, along with its partners, sent a petition to the FDA to revoke its approval for four carcinogenic chemicals approved for use in food. One was methylene chloride.

The health advocacy groups argue that the U.S. government has been disregarding the Delaney Clause, part of the Federal Food, Drug and Cosmetic Act since 1958.

The clause requires the FDA to ban additives that are found to cause or induce cancer in humans or animals as indicated by testing.

The FDA filed the petition for consideration in December and accepted public comments until March 11. The petition is currently being reviewed.

What does Health Canada say?

Methylene chloride was assessed in Canada in 1993 and was classified as “probably carcinogenic to humans” based on available evidence at the time.

Since then, the government has continued to collect information about methylene chloride and has recently prioritized it for further assessment.

Data on potential health effects and emerging science will be considered in determining whether methylene chloride is toxic under the Canadian Environmental Protection Act.

If so, the government will take action to protect Canadians, including, if needed, no longer allowing the chemical to be used in the production of foods such as decaf coffee and tea.

What to do

If you’re concerned about methylene chloride, you can avoid it without giving up your decaf.

Look for decaf coffee products made using the “Swiss Water Process,” a method that does not use chemical solvents to extract caffeine. Decaf coffee served at Tim Hortons and Second Cup comes from beans processed this way. (Starbucks uses the European method to decaffeinate its beans.)

You can also choose products labelled certified organic, solvent-free or naturally decaffeinated with carbon dioxide.

Leslie Beck, a Toronto-based private practice dietitian, is director of food and nutrition at Medcan. Follow her on Twitter @LeslieBeckRD

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