The health benefits of drinking coffee are pretty impressive.
It has been shown to enhance brain function, increase metabolic rate and improve exercise performance (1, , ).
A regular intake has also been linked with a lower risk of dementia, Alzheimer's, Parkinson's and type 2 diabetes (, , , , , , ).
To top it off, coffee drinkers seem to live longer (, ).
However, coffee also contains a potentially harmful chemical called acrylamide.
The chemical acrylamide (or acrylic amide) is a white, odourless, crystal compound. It has the chemical formula C3H5NO.
It's used to make plastics and treat waste water, among other things.
Overexposure at work can cause damage to the nervous system, and it's also thought to increase the risk of cancer (, , ).
Day-to-day we are exposed to acrylamide through smoking and secondhand smoke, as well as personal care products and household items.
In 2002, Swedish scientists also discovered it in a wide range of foods, including baked goods and coffee ().
Scientists believe the acrylamide in food is a product of the Maillard reaction. This reaction occurs when sugars and amino acids are heated above 248° F, or 120° C (, ).
What we do know is that when coffee beans are roasted, acrylamide is formed. There's no way to remove acrylamide from coffee, so when you drink it, you're exposing yourself to the chemical ().
Bottom Line: Acrylamide is a potentially harmful chemical formed during the coffee bean roasting process.
Acrylamide can definitely be harmful.
Yet, as is often the case in nutrition, the devil is in the dose.
Workplace exposure to very high doses of acrylamide can cause nerve damage and disorders of the nervous system (, ).
Studies in animals have also repeatedly shown that acrylamide causes cancer when eaten.
However, the doses given to animals have been 1000–100,000 times larger than the amounts humans are exposed to through diet.
Humans also metabolize acrylamide differently, so we are exposed to a lower dose of the chemical when our body breaks it down ().
Unfortunately, there are few human studies on the safety of acrylamide in food, and the results have been inconsistent ().
It's also important to keep in mind that acrylamide is not a new problem. Despite only recently being discovered in our food, it's likely to have been there in some amount since man started cooking.
Bottom Line: Workplace exposure to high amounts of acrylamide can cause nerve damage. In very high doses, acrylamide is known to cause cancer in animals. We don't know how much of it is safe for humans.
The amount of acrylamide in coffee varies greatly.
A 2013 study analyzed 42 samples of coffee, including 11 instant coffees and 3 coffee substitutes (grain coffee).
They found instant coffee to have 100% more acrylamide than fresh roasted coffee, while coffee substitutes had 300% more ().
They also noted that acrylamide levels peak early in the heating process and then decline. So lighter colored coffee beans have more acrylamide than darker ones that are roasted longer.
Bottom Line: The amount of acrylamide in coffee can vary greatly. Well roasted, dark, fresh coffee beans are likely to have the lowest amount.
While a link between acrylamide intake and cancer in humans hasn't been proven, it cannot be ruled out.
However, coffee drinking has not been shown to increase your risk of cancer. In fact, it's linked with a reduced risk of developing some types of cancers ().
For example, in one study, people who increased their coffee intake by 2 cups per day had a 40% lower risk of liver cancer ().
Coffee drinking is also linked to a plethora of other health benefits, such as living longer and a reduced risk of many diseases.
Bottom Line: Coffee hasn't been shown to increase your risk of cancer. It has actually been linked with a reduced risk of some types of cancers, such as liver cancer.
Avoiding acrylamide completely is not possible.
At the moment we consume less acrylamide than the maximum exposure levels recommended by the European Food Safety Authority (25).
While it's not possible to buy coffee that is completely free of acrylamide, the coffee industry is working on practical solutions to reduce its presence (26, ).
Given the potential health benefits of coffee, it's not something you need to cut out.
Bottom Line: Coffee contains many other chemicals that may be beneficial to your health; cutting it out isn't necessary.
There is no evidence that small amounts of dietary acrylamide cause harm.
However, if you are concerned, then here are a few steps you can take to minimize your exposure:
- Quit smoking and try to minimize your exposure to secondhand smoke.
- Keep frying to a minimum, as it produces the most acrylamide of all cooking methods.
- Try not to burn or char foods on the grill.
- Toast bread to a light brown color and avoid burnt toast.
- Boil or use the microwave when possible.
- Store potatoes out of the fridge ().
- Let your bread dough proof longer -- the fermentation of yeast reduces the amount of asparagine in the dough, so less acrylamide is made ().
- Choose dark roasted coffee and avoid instant coffee and coffee alternatives.
Bottom Line: Completely avoiding acrylamide is impossible. However, you can make a few changes to reduce your acrylamide intake.
Coffee contains various substances that are linked to positive effects on health.
These outweigh the potential negative effects of acrylamide, so there's no need to stop drinking coffee if you enjoy it.