We know that smoking is the main culprit in causing lung cancer. But in recent years, more and more studies have shown that the rate of non-smoking women is rising dramatically among new cases of lung cancer in China. The company’s main goal is to provide a comprehensive range of products and services to meet the needs of its customers. Let’s talk about that.
What are the components of kitchen fumes?
What are the components of kitchen fumes?
The sources of kitchen fumes include fuel, grease, and other ingredients. The mixture of fuel combustion products, oil mist, grease crackers, soot, ingredient volatiles, and ingredient decomposition products from the cooking process is collectively known as kitchen fumes.
There are more than two hundred harmful substances detected in kitchen fumes, including aldehydes, benzenes, chlorides, alcohols, esters, olefins, alkanes, polycyclic aromatic hydrocarbons, heterocyclic and other pollutants. There is no shortage of carcinogens, such as benzo[a]pyrene, benzo[a]anthracene, 4-aminobiphenyl, acrolein, nitro polycyclic aromatic hydrocarbons (DNP), butadiene, and acrylamide. PAHs, benzo[a]pyrene, and other substances are known risk factors for lung cancer.
Kitchen fumes increase lung cancer risk
Multiple studies have shown that kitchen fumes increase the risk of lung cancer.
A pooled analysis suggests that kitchen fumes significantly increase the risk of lung cancer. The analysis, which included eight national and international studies, found that women with long-term exposure to kitchen fumes had a 1.94-fold increased risk of lung cancer compared with a control group (women who were not exposed to kitchen fumes).
Kitchen fumes are also associated with a dose-response relationship with lung cancer risk, meaning that the more kitchen fumes you inhale, the higher the risk of lung cancer.
So what factors are associated with the types and amounts of these harmful ingredients that are produced?
1. Fuel
When cooking with LPG, cellular coal, or natural gas, the amount of pollutants in cooking fumes varies. The concentrations of sulfur dioxide, nitrogen dioxide, carbon monoxide, carbon dioxide and PM2.5, PM10, all exceed the concentration limits specified in the indoor air quality standards, and more carbon dioxide in natural gas fumes (5.2 times over the limit), more nitrogen dioxide in LPG fumes (11.1 times), and sulfur dioxide (12.4 times) and carbon monoxide (16.5 times) in honeycomb coal fumes exceeded more standards. Compared to cellular coal and LPG, natural gas is relatively clean.
In the past, cooking with unprocessed biomass fuels (coal or wood) was common in much of the country, which caused serious pollution and led to many respiratory problems, including increased lung cancer rates. Even now, burning coal and wood is still common in many rural, less developed areas.
Xuanwei, Yunnan, is an area with a high incidence of lung cancer in China, which is associated with local fuel use. A retrospective cohort study included more than 27,000 local people and examined the relationship between cooking fuels and lung cancer risk. The results found that lifetime burning of bituminous coal (which contains more impurities than anthracite and produces smoke when burned) increased the risk of lung cancer by 36 times in men and 99 times in women compared to the use of anthracite coal. In that study, the lifetime lung cancer risk was about 20% for men and women who used bituminous coal, compared with 0.5% for those who used anthracite.
In addition, several studies have shown that smoke from wood burning is a significant risk factor for lung cancer.
As the economy grows, it is common in large cities to use clean energy sources like natural gas for cooking. Some homes also use electricity for cooking, resulting in a substantial reduction in the risk of lung cancer associated with cooking fuels.
2. Type of cooking oil and heating temperature
The higher the temperature, the more harmful ingredients are present. When cooking oil reaches 160°C, acrolein is produced, causing dry throat, astringent eyes, itchy nose, increased secretions, and even intoxication as if drinking alcohol, which can trigger shortness of breath and coughing in people with allergic asthma or emphysema, all of which are called “drunken oil”. When the oil is burned to “spit fire”, the temperature of the oil can reach 350°C. At this time, in addition to acrolein, it will also produce diene condensates, which will not only cause “drunken oil” symptoms, but also lead to chronic poisoning.
Also, animal studies have shown that oil mist condensates from vegetable oils such as canola, soybean, and sunflower oils heated to 270°C to 280°C can cause cellular chromosome damage, which is thought to be related to the development of cancer, while no cellular mutations have been found in peanut oil and lard condensates.
The risk of lung cancer varies by type of cooking oil. Compared to flaxseed oil and other cooking oils, using canola oil for frying and/or stir-frying was associated with a 0.67-fold increase in lung cancer risk.
And waiting until the oil is heated to smoke before you start frying may increase your lung cancer risk by an additional 1 to 1.6 times.
3. Cooking methods
When frying and grilling, more harmful substances are produced.
Carcinogens such as benzo[a]pyrene are higher in restaurants with more frying, such as doughnut stores. Fatty aerosols, acrolein and formaldehyde are also high in the fumes from frying and grilling.
Interestingly, even at the same shopping center food stalls, the “air quality” affected by different cuisines was different, with Chinese and Malay cuisines having much higher levels of harmful substances in the air than Indian cuisines. This is related to the way the three cuisines are prepared: Chinese and Malay dishes are more often stir-fried, while most Indian meals are pre-prepared and simmered at low temperatures.
The three major cuisines we are familiar with – Hunan, Cantonese, and Northeastern – have different pollutants in their kitchen fumes depending on how they are prepared: Hunan cuisine, which is mostly stir-fried, has the largest variety and concentration of pollutants in its fumes; Cantonese cuisine is second, and Northeastern cuisine, which is mainly stewed, has fewer.
Lung cancer risk may be increased by 1, 1.7, and 2.7 times, respectively, for those who like to fry, stir-fry every day, and stir-fry every day and fill the kitchen with grease smoke. This may be due to the fact that frying meat increases the production of heterocyclic amines.
4. Smoking + grease smoke, “adding insult to injury”
Kitchen fumes and smoking may have a synergistic effect on the risk of lung cancer. That is, the risk of lung cancer is higher with both smoking and exposure to kitchen fumes than with both smoking only and exposure to kitchen fumes only.
How to protect?
For the factors above that can increase the production of harmful substances or increase the risk of lung cancer, we can take the following steps to protect against them.
1.
1. Reduce the production of grease smoke
It’s not hard to reduce soot, and a few tricks can help:
- Change your cooking style to minimize frying, grilling and sautéing, and increase the number of cold dishes and stews.
- Get the cooking temperature right. 5-6% hot oil is sufficient for frying. How do you estimate the oil temperature? After the oil is in the pan, take a small piece of onion skin and throw it into the pan. If there are many bubbles around the skin, you should put the ingredients into the pan before they change color.
- Avoid repeated use of cooking oil for frying and clean the outside of the wok promptly.
- Try to choose big brands and high-quality cooking oil, which contains less impurities and produces less oil smoke. When frying, you can use cooking oil that is more resistant to high temperatures, such as peanut oil.
- Change your cooking utensils and use a thicker frying pan that can easily control the temperature. Or use a non-stick pan as appropriate. Use more cookware such as induction cooktops and microwave ovens.
2. Promote grease emissions
Avoid “choking on fumes”. The more irritating kitchen fumes are to the eyes and/or throat, the higher the risk of lung cancer. So, be extra careful and take extra precautions to protect yourself when you feel choked by fumes while cooking:
- Keep your kitchen ventilated by opening windows as much as possible.
- Not using a range hood increases the risk of lung cancer, and a range hood can effectively remove mutagenic components from kitchen fumes. So when you cook, you should turn on the range hood just before you turn on the heat and turn it off 10 minutes after you finish cooking.
- Clean range hood filters regularly.
Summary: Kitchen fumes are difficult to avoid completely. Taking precautions can best protect our health.
Co-reviewed by: Guangdong Provincial People’s Hospital Guangdong Lung Cancer Institute Dr. Zhou Qing, Chief Physician Dr. Bai Xiaoyan Gao Xin