Do air fryers cause cancer? Is cooking without oil healthier? The reliable answer is...

Fried foods have a crispy texture and pleasant aroma and are loved by many people.

I believe everyone is familiar with the air fryer.

Many friends use it to fry French fries, bake egg tarts, bake sweet potatoes...

One of its major selling points is that non-fried foods are healthier, but there is also another voice: food fried in an air fryer can cause cancer.

So, does eating food cooked in an air fryer cause cancer? Is cooking without oil really healthier? Let's find out today.

1

No oil required

How does an air fryer fry food?

When we cook food, we generally use heating methods, including direct heating and indirect heating, and the most commonly used method in life is indirect heating.

Typically, indirect heating uses a heat transfer medium to heat and cook the food.

Traditionally, deep-fried foods are made by heating the oil first and then immersing the food in the hot oil, mainly using heat conduction to fry the food.

The air fryer places food in a small enclosed space, uses air as a heat transfer medium, heats the air in the space, and uses a fan to accelerate the flow of gas, carry away water vapor, and form a circulating hot air. It mainly "frys" food by convection.

When people use an air fryer to "fry" some foods with very little fat content, they often apply a little cooking oil. At this time, some small oil droplets may be mixed in the hot air, forming an oil mist effect.

However, it is difficult to achieve the same effect as frying food in a microwave oven.

Microwave ovens mainly use electromagnetic energy to heat food in the oven. When food is placed in a microwave oven, microwaves will cause the water molecules in the food to reciprocate at a high frequency, producing an "internal friction" effect and generating a thermal effect.

Therefore, food processed in a microwave oven is often heated both inside and outside at the same time. Whether it is traditional frying or air frying, the heating method is to transfer heat from the outside to the inside. This process will inevitably form a temperature gradient (i.e. temperature difference) inside and outside the food, so the effect of crispy outside and tender inside can be achieved. Even a microwave oven with hot air convection heating function finds it difficult to achieve the same effect.

2

Can food cooked in an air fryer cause cancer?

Air fryers also use high temperatures to heat food.

Therefore, food will undergo some physical and chemical changes during the cooking process, such as improved texture and the production of special flavors. It may also produce some chemical components that are harmful to the human body, such as acrylamide.

Acrylamide is a carcinogen and has been classified as a Class 2A carcinogen by the World Health Organization's International Agency for Research on Cancer (IARC). This type of carcinogen is mainly based on carcinogenicity data from experimental animals, but it is likely to be carcinogenic to humans as well.

There are several ways in which acrylamide is produced in food. The main one is the Maillard reaction between asparagine and reducing sugars, which actually occurs during the processing of many foods.

Scholars in my country have conducted relevant research on nearly 350 kinds of food on the market. The results showed that acrylamide can be detected in most food samples, but its average exposure (i.e. intake) in our diet is relatively low, estimated to be only 0.38μg/kg·day, while the average exposure reported by the Food and Agriculture Organization of the United Nations and the World Health Organization is 1μg/kg·day.

Therefore, there is no need to worry too much about the claim that food cooked in an air fryer can cause cancer.

In addition, using an air fryer is mainly a way to replace traditional fried foods. On the one hand, it can avoid excessive intake of fat, and on the other hand, it can reduce the intake of other potentially harmful polymers produced by fat during high-temperature frying.

3

Is cooking without oil really healthier?

People who pursue oil-free cooking are mainly worried about consuming too much oil, which will cause triglycerides to accumulate in adipose tissue and cause obesity.

But everyone should also know that the most fundamental cause of obesity is that energy intake exceeds energy consumption, and the remaining energy is converted into fat and stored in the body.

Furthermore, fat (acid) is an important body component and energy source. We need to take in a certain amount of fatty acids every day, such as linoleic acid and α-linolenic acid, which cannot be synthesized by the human body. A large part of them needs to be obtained through edible oil, and a lot of vitamin E, which is essential to the human body, also needs to be obtained through edible oil. In addition, edible oil also helps us absorb and utilize some fat-soluble components in food.

Therefore, do not excessively pursue oil-free cooking. Long-term intake of too little cooking oil can easily lead to insufficient intake of unsaturated fatty acids, affecting memory and brain nerve function. It may also affect the clearance of low-density lipoprotein in the blood and induce some cardiovascular and cerebrovascular diseases.

4

How to eat fried foods relatively healthily?

First, don't eat too much.

Fried foods often have too high a fat content and are high-energy foods. Eating too much can easily lead to excessive energy intake.

Secondly, do not fry food for too long. For example, it takes about 1-2 minutes for vegetarian dishes, and slightly different for meat dishes depending on the thickness of the ingredients. Generally, you only need to fry until the surface is slightly yellow but not burnt.

When exposed to high temperature for a long time, oils and fats are prone to complex chemical changes such as hydrolysis, condensation, and polymerization, which may produce a variety of components that are harmful to the human body.

Third, be careful not to use too much seasoning, especially salt.

Source: Science China (ID: Science_China)

Expert of this article: Zhang Zhaomin, Master of Food Science, Senior Engineer