"59 types of coffee were found to contain carcinogens", so coffee can no longer be drunk safely? The truth is →

Recently, the topic #59 types of coffee all found to contain carcinogens# has become a hot search topic. The Fujian Provincial Consumer Council conducted a comparative test on 59 types of freshly brewed and sold coffee from 20 coffee sales units in Fuzhou City, and all of them were found to contain low levels of Class 2A carcinogen "acrylamide". This news surprised "coffee lovers" and they even began to hesitate whether to drink the coffee in their hands.

Image source: Weibo screenshot

Is the truth really that scary? In this article, we will talk about the fact that "coffee causes cancer" and tell you which type of coffee has the least acrylamide. Let you choose the right coffee and drink it with confidence.

Why does coffee contain acrylamide?

In fact, it is normal to detect acrylamide in coffee, which is related to the coffee processing process. Green coffee beans contain sucrose and asparagine, which will undergo the Maillard reaction at high temperatures. Acrylamide is one of the by-products of the Maillard reaction.

Generally speaking, acrylamide is easily produced when the cooking temperature is higher than 120℃, and the temperature when roasting coffee beans is almost always higher than this, so it is not surprising that there is acrylamide in coffee. Some researchers roasted raw coffee beans at 125℃ for 30 to 60 minutes. The acrylamide content gradually increased in the first half hour. When it was extended to 40 minutes, the acrylamide content was the highest. When it was continued to roast for 50 and 60 minutes, the acrylamide content gradually decreased, but it was slightly higher than the content at 30 minutes.

However, it is precisely because of the existence of the Maillard reaction when roasting coffee beans that coffee has a unique aroma. The Maillard reaction produces more than 800 aroma substances, and under the joint action of these aromas, coffee has a complex and aromatic flavor.

Image source: Pixabay

Which coffee has lower acrylamide?

The acrylamide content in coffee is affected by many factors, such as the type of raw materials, degree of roasting, and processing methods.

1. Raw materials

Different coffee beans produce different amounts of acrylamide after processing. Coffee varieties are mainly divided into small-grain coffee (Arabica coffee), medium-grain coffee (Robusta coffee) and large-grain coffee (Liberica coffee). Liberica coffee beans are generally unpopular and rarely used commercially due to their poor aroma, bitter flavor and different sizes. Of the other two types, the acrylamide content of Arabica coffee after roasting is significantly lower than that of Robusta coffee. The Yunnan small-grain coffee, which is currently more popular on the market, is a type of Arabica coffee.

Image source: Pixabay

2 baking degree

The degree of coffee bean roasting is a key factor affecting acrylamide content. Some researchers used the hot air method to roast Arabica coffee beans and compared the acrylamide content in coffee beans obtained by light roasting (roasting for 6 minutes, final temperature 147°C), medium roasting (roasting for 11 minutes, final temperature 172°C), and deep roasting (roasting for 18 minutes, final temperature 191°C). The results showed that the amount of acrylamide accumulated in medium roasted coffee beans was the highest, while the acrylamide content in lightly roasted and deeply roasted coffee beans was relatively low.

Many people may be surprised: Why is the acrylamide content not high in deep roasted coffee beans? This is because, due to the long roasting time, asparagine and sucrose are completely consumed, the melanoidin content gradually increases, and the high temperature promotes the nucleophilic addition reaction of acrylamide and melanoidin and the volatilization of acrylamide, which reduces its content.

3. Processing method

There are two types of coffee on the market: freshly ground coffee and instant coffee. Freshly ground coffee is the coffee obtained by grinding, boiling and extracting roasted coffee beans. Different coffee making processes will affect its acrylamide content. Overall, Turkish coffee> Italian coffee> American coffee.

There are also documents showing: brewed coffee (Turkish coffee) > immersion method (French press coffee) > extraction method (filtered coffee) > Italian press method (espresso).

Instant coffee is made by roasting, grinding, extracting coffee beans, concentrating them appropriately, and then spray drying or freeze drying them to get instant coffee powder. The aroma and flavor of instant coffee are not as good as freshly ground coffee, and pre-drying and spray drying will cause some acrylamide to volatilize, so the acrylamide content of instant coffee is generally lower than that of freshly ground coffee.

Regarding acrylamide, should we worry about it?

When it comes to acrylamide, everyone’s first reaction is “carcinogenic”, which is why they become anxious and panic. In fact, there is no need to worry too much about it.

Although a large number of in vivo and in vitro animal experimental studies have shown that acrylamide has obvious mutagenic effects, can cause chromosomal aberrations in rats, and lead to tumor growth in multiple tissues and organs such as the rat mammary gland, thyroid gland, and adrenal gland. However, there is currently no direct evidence to prove that acrylamide is carcinogenic to humans. Therefore, acrylamide is classified as a Class 2A carcinogen by the International Agency for Research on Cancer (IARC), which means a substance that is "probably carcinogenic to humans." For us, Class 2A carcinogens are not unfamiliar and are always around us, such as the red meat of pork, beef, and mutton that many people eat every day.

Besides, the potato chips, French fries, baked steamed bread slices, baked sweet potatoes, bread, pancakes, fried dumplings, and fried dough sticks that we usually eat all contain acrylamide, and a WHO survey shows that potato chips have the highest acrylamide content among foods. As the frying time of potato chips and French fries increases, the acrylamide content will also rise sharply, and is expected to increase by 10 to 20 times.

At present, the amount of acrylamide consumed by Chinese people is very small, so it is safe. In addition, Chinese people actually drink very little coffee, so the amount of acrylamide consumed through coffee is very small, not even as much as the fried dough sticks and pancakes you eat in the morning or the stir-fried dishes you usually eat.

Therefore, for those workers who only drink one or two cups of coffee a day to "prolong their lives", there is no need to worry that drinking coffee will cause cancer.

Image source: Pixabay

Some substances in coffee can reduce the risk of cancer

Coffee contains a series of biologically active chemicals, including the diterpene cafestol, polyphenols, caffeine and chlorogenic acid, which may affect health and reduce the occurrence of cancer through various mechanisms.

A meta-analysis showed that the risk of endometrial cancer was significantly inversely correlated with caffeinated coffee, but not with decaffeinated coffee. Several studies have also found that coffee intake has a protective effect on cancers in multiple sites, especially endometrial cancer, liver cancer, melanoma, oral cancer, and pharyngeal cancer.

However, don't choose three-in-one coffee. In addition to coffee powder, this type of coffee also contains creamer, sugar, oil, etc. Drinking it often will not only make you fat, but also increase the risk of cancer. Survey data shows that compared with people who don't drink coffee often, people who are used to drinking two-in-one or three-in-one instant coffee have a 152% higher risk of breast cancer, while people who are used to drinking freshly brewed coffee have a 52% lower risk of breast cancer.

Therefore, for those who like to drink coffee, try to drink freshly brewed coffee, don’t choose three-in-one coffee! Pure instant coffee powder is also OK.

How much coffee is appropriate to drink every day?

The "Scientific Consensus on Coffee and Health" jointly released by the Nutrition and Health Institute of the Chinese Center for Disease Control and Prevention, the Food Hygiene Branch of the Chinese Preventive Medicine Association and five other institutions recently recommended that the daily caffeine intake of ordinary adults should be controlled within 400 mg.

This is equivalent to no more than 4 cups of pure coffee (150ml/cup). For branded coffee, you can calculate the number of cups by comparing the caffeine content of each cup on the package label. If it is a small bag of 1.8~2g instant coffee, no more than 5 bags per day.

In addition, drinking coffee is not recommended for children and adolescents, the elderly, pregnant and breastfeeding people, people with hypertension, glaucoma patients, people with a genetic tendency to high intraocular pressure, and people with osteoporosis.

Image source: Pixabay

Summarize:

Coffee lovers don't need to panic. It's normal for coffee to contain acrylamide. As long as you don't drink it excessively for a long time, there is no obvious health risk. If you are really worried, then choose Yunnan small-grain coffee, Italian coffee, American coffee or pure instant coffee powder (don't choose three-in-one!).

By the way, many workers still have to rely on coffee to "survive", cheers!

References

[1]ALSHAWIAH. The effect of different roasting durations on the acrylamide concentrations in hearabiccoffeebeverages [J]. Current Nutrition and Food Science, 2019, 15 (7): 678-684.

[2] Written by Nathan Myhrvold, Chris Young, and Maxime Billet; Photographed by Ryan Matthew Smith and Nathan Myhrvold; Translated by the Modernist Cuisine Translation Team. Modernist Cuisine: The Art and Science of Cooking, Volume 4: Ingredients and Preparation [M]. Beijing: Beijing Fine Arts Photography Publishing House, September 2016.

[3] Bai Jie, Zhu Yuchen, Chen Fang. Research progress on the formation and control of acrylamide in coffee[J]. Food Science, 2022, 43(21): 332-340.

[4] MICHALAKJ, KUJAWSKAMC, GUJSKAE, etal. Effect of the brewing process on the acrylamide content incoffee beverages [J. Proceeding soft the Nutrition Society, 2020, 79 (293): 15-18.

[5] Chen Yuanling, Wu Hui. Research progress on acrylamide in coffee[J]. Food Safety Guide, 2021(30):179-180.DOI:10.16043/j.cnki.cfs.2021.30.093.

[6] Chen Huiyi, Gao Min, Li Xiaoguang. Coffee intake and cancer risk: an umbrella review of meta-analysis [J/OL]. Shanghai Preventive Medicine: 1-14 [2023-12-09]. http://kns.cnki.net/kcms/detail/31.1635.R.20230725.0830.002.html.

[7]Lee, PriscillaMingYietal. "AssociationsbetweenCoffeeProductsandBreastCancerRisk:aCase-ControlstudyinHongKongChineseWomen."Scientificreportsvol.9,112684.3Sep.2019,doi:10.1038/s41598-019-49205-x

Produced by: Science Popularization Department of China Association for Science and Technology

Producer｜China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

Author: Xue Qingxin, member of Chinese Nutrition Society, registered nutritionist, health manager, public nutritionist

Review | Ruan Guangfeng, Deputy Director of Kexin Food and Health Information Exchange Center