Does drinking coffee cause cancer? Nutritionist: Choose the right coffee beans, brew less coffee, and you’re good to go!

Recently, there has been a rumor on the Internet that "drinking coffee can cause cancer because it contains acrylamide, a carcinogen that can even damage the kidneys and cause reproductive toxicity." At first glance, this may cause panic among coffee lovers. But what is acrylamide? Will accidentally ingesting acrylamide have any impact on human health? Nutritionists say that as long as you choose the right coffee beans, pay attention to the roasting temperature, and try to "brew" coffee as little as possible, you don't have to worry too much about stepping on a cancer-causing landmine.

Green coffee beans are heated and roasted, which will contain acrylamide

Acrylamide is a chemical substance. The World Health Organization currently classifies acrylamide as a Class II carcinogen (2A carcinogen). Acrylamide is produced by the Maillard reaction of "reducing sugars" such as glucose and fructose and certain amino acids (mainly aspartic acid) during high-temperature frying and baking. Green coffee beans themselves contain various ingredients, such as carbohydrates, proteins, oils, organic acids, etc. After heating and roasting, a series of reactions will occur, producing a mellow smell. The two most important reactions are caramelization and Menard reaction, so acrylamide is also contained in them.

Nutritionist: There is insufficient evidence to prove that acrylamide is carcinogenic to humans

Although animal experiments have found that acrylamide has a carcinogenic risk, there is insufficient evidence to prove that it is carcinogenic to humans. Nutritionist Lin Shihang said that in fact, the content of acrylamide in coffee is extremely low and can be metabolized by a normal and healthy human body. However, whether it is the choice of coffee bean variety, defective coffee beans, roasting temperature, or brewing method, all four aspects will affect the concentration of acrylamide:

1. Robusta coffee beans, which have a higher acrylamide content

The two varieties of coffee beans with the highest market share are Coffea arabica and Coffea robusta, accounting for 80% and 20% respectively. The difference in variety affects the acrylamide content.

In fact, "asparagine" and "sucrose" are the key factors in the formation of acrylamide. Generally speaking, Arabica coffee beans have a higher "sucrose" content, while Robusta beans have a higher free "asparagine". Research shows. "Asparagine" is a key factor in the formation of acrylamide.

2. Unripe beans, worm-eaten beans, and moldy beans have high acrylamide content

Coffee beans occasionally have defects, such as unripe beans, insect-infested beans, moldy beans, etc. Studies have found that unripe fruits contain more asparagine, so it is more likely to produce acrylamide during subsequent roasting. Generally speaking, specialty coffee beans are sorted several times to remove these defective beans, so the proportion of unripe beans will be much lower. However, if it is a cheaper coffee bean, Robusta may be added to save costs and have a stronger flavor. In this case, the acrylamide content may be higher than that of specialty coffee.

3. Lightly roasted coffee beans have a higher acrylamide content

Nutritionist Lin Shihang said that coffee beans will make two popping sounds when roasting, and the roasting degree can be roughly distinguished according to the popping sounds. The period before and after the first crack is called "light roast", the period from the end of the first crack to the second crack is called "medium roast", and the middle to the end of the second crack is called heavy roast. The temperature during roasting is very high, and the temperature of the coffee beans will gradually rise to over 200 degrees. Such a high temperature environment is conducive to the formation of acrylamide. Studies have shown that acrylamide is produced in the largest amount in the first minute of roasting, which means that the content of acrylamide in "light roasted" beans is higher than that in medium roasted and dark roasted coffee beans.

In addition to promoting the formation of acrylamide, high temperature will also cause continued cracking of acrylamide! If the raw materials that can produce acrylamide have all reacted in the early stage of roasting, this also means that there is no raw material to produce acrylamide after the middle stage of roasting, and acrylamide continues to degrade, so the content of medium and heavy roasted coffee beans will be much lower than that of light roasted coffee beans.

However, there is no need to abandon lightly roasted coffee beans. The acrylamide content in light roasted coffee beans does not actually cause serious harm to the body, and the nutritional value of light roasted coffee beans is much higher than that of medium and dark roasted coffee beans. For example, they contain chlorogenic acid and caffeic acid, so "light roasted" is still an option.

4. Brewed coffee has a higher acrylamide content

Nutritionist Lin Shihang said that since acrylamide is highly soluble in water, it can easily dissolve in coffee liquid. Since coffee is brewed for the longest time and at the highest temperature, the amount of acrylamide dissolved is also the highest. The extraction time of espresso is short, and the complete extraction takes about 25-30 seconds, which will reduce the amount of acrylamide dissolved. There are three main ways to brew coffee:

★「Boil」: Put the coffee powder into boiling water and boil it, such as Turkish coffee.

★ "Drip": Pour hot water into coffee powder, and the coffee extract gradually drips out, for example: hand brewing.

★「Pressure」: Using pressure to force liquid to flow through coffee powder, for example: espresso.

The domestic Food and Drug Administration stated that Taiwan recommends that the content of acrylamide in every kilogram of coffee should be less than 450 ppb. In addition to the safe intake amount, acrylamide is actually hidden in many foods. According to research on the acrylamide content in food by the European Union and the United States, potato chips rank first, followed by roasted coffee. A study by the Hong Kong Food Safety Center found that acrylamide can also be produced when vegetables are fried. For example, zucchini, garlic and onion are the top three vegetables with the highest content. However, relevant research in Taiwan shows that coffee ranks after potato chips, brown sugar, fried dough sticks and biscuits, and the value is far lower than the research data in Europe and the United States.

Although acrylamide is produced during the roasting process of coffee, it does not pose a health hazard based on our drinking habits and intake. In addition, coffee contains many phytochemicals, especially lightly roasted coffee, so coffee is still a very healthy drink, so there is no need to worry too much!