Oct 2, 2017

Does coffee get a Prop 65 warning? What is acrylamide? Is it true that coffee and cocoa contain this toxin?

ConsumerLab: Acrylamide is a neurotoxin and probable carcinogen (cancer causing agent) formed when certain starchy foods, such as wheat and potatoes, are cooked at high temperatures (>248 degrees Fahrenheit). It can also be produced when coffee and cocoa beans are roasted. Although no level of exposure is absolutely safe, amounts of acrylamide consumed by most adults is believed to represent a very low level of risk. Nevertheless, there are steps you can take to reduce your exposure. 

How much is safe? 
Exposure to even extremely small amounts of acrylamide may very slightly increase cancer risk, which has led the State of California to require a cancer warning on foods providing more than 0.2 mcg of acrylamide per daily serving (below which there is no significant risk of cancer), although up to 140 mcg is permitted before a warning regarding reproductive toxicity is required. The U.S. EPA also uses this higher 140 mcg amount (based on 2 mcg of acrylamide per kilogram of body weight) as its chronic reference dose for risk to the nervous system. 

How much is in what we eat? 
An adult weighing 150 lb consumes about 35 mcg of acrylamide per day (0.5 mcg/kg of bodyweight) (Mucci, J Agric Food Chem 2008). This is way below the 140 mcg limit of the EPA, although way above California's very stringent limit of 0.2 mcg, noted above. 

In the U.S., fried potato products (i.e., French fries, potato chips, roasted potatoes) account for the greatest source of acrylamide in the diet, accounting for up to 38% of average exposure for adults, followed by crackers, cookies and cakes (17%), bread (14%), snacks such as roasted nuts, and popcorn (14%), cereal products (9%), and lastly, coffee (8%) (Friedman, J Agric Food Chem 2008). 

Green coffee beans contain asparagine (it is the second-highest concentration amino acid in coffee beans) as well as sucrose (sugar). When roasted, significant amounts of acrylamide can be produced; however, brewed coffee (most of which is water) contains only about 2 mcg per 8-ounce cup of coffee. 

As with coffee beans, cocoa beans are typically roasted during processing, resulting in the production of acrylamide. FDA tests of various cocoa powders and dark chocolate baking bars in 2002 showed amounts of acrylamide ranging from 0.29 mcg to 4.5 mcg per serving (see the Acrylamide table in the Dark Chocolates and Cocoas Review); however, there was no detectable acrylamide found in a popular milk chocolate bar. 

What can I do to reduce my acrylamide intake? 
Limit your intake of roasted, baked and fried potatoes, chips, etc. Store raw potatoes in a cool dry place, such as a pantry or cupboard — not in the refrigerator, as the cold temperature increases the amount of sugars in potatoes, increasing acrylamide generation during high-heat cooking. Fry at the lowest possible temperature for the shortest possible amount of time (aim for a golden yellow color rather than golden brown) (Prop 65 Acrylamide Fact Sheet 2017). Soaking sliced potatoes in water for 15 to 30 minutes (or for 5 minutes in warm, slightly salted water) before frying or roasting may also reduce acrylamide formation (Pedreschi, J Sci Food Agric 2014). 

Several factors can modestly reduce the amount of acrylamide in your coffee when prepared at home (Soares, Coffee in Health and Disease Prevention 2015):

  • Choose coffee made from Arabica beans, which contain lower amounts of asparagine than Robusta beans. However, be aware that this won't guarantee lower acrylamide, since amounts are also affected by roasting time, temperature, etc.

  • Store coffee before using for longer periods of time. Acrylamide levels in commercial ground coffee and beans decrease over time when stored in their original container. Reductions of 40—60% have been reported in coffees stored at room temperature over a period of 6—12 months.

  • Plunger pot and filtered, drip brew coffee preparation typically results in less acrylamide than coffee prepared by decoction (such as Turkish coffee) and pressure preparation (French press, expresso).

Milk chocolate and alkalized cocoa products may contain less acrylamide than non-alkalized dark chocolate, but will also contain lower amounts of healthy flavanols

The bottom line: 
Acrylamide is a neurotoxin and probable carcinogen formed when cooking certain foods at high temperatures. Fried and roasted potato products are the greatest source of dietary acrylamide exposure in the U.S. Brewed coffee and cocoa also contain small amounts of acrylamide. It is possible to reduce exposure to acrylamide by avoiding certain foods and modifying the way you prepare potatoes and coffee, as discussed above.