Cancer is becoming more common with the growth of the global population and the increase in life expectancy. Data shows that by 2030, the number of new cancer cases worldwide is expected to rise to 21.7 million, and the number of cancer deaths is projected to increase to 13 million [1].
In our country, more than 10,000 people are diagnosed with cancer every day, with 7.5 individuals confirmed every minute [2].
A popular belief circulating online states, "Meat is unhealthy, eating meat can cause cancer, and a vegetarian diet can prevent cancer." Is this really the case? The answer is not so straightforward.
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There is ample evidence to suggest that the consumption of red meat (such as pork, beef, and lamb) and processed meats (such as sausages, bacon, and hot dogs) can increase the risk of colorectal cancer [3].
Not only that but there are as many as 15 types of cancer associated with the intake of red meat and processed meat products [4]. The International Agency for Research on Cancer has classified red meat and processed meat products as "Group 1 carcinogens."
Although the carcinogen classification does not equate to the intensity of carcinogenicity, it also clarifies that red meat and processed meats are substances that have carcinogenic effects on the human body.
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Currently, the carcinogenic mechanisms of red meat and processed meat products are not entirely clear, but possible reasons include the following:
1. Compared to poultry and seafood, red meat contains more heme iron, which may lead to the production of free radicals that can damage DNA and promote the formation of nitro compounds, causing damage in the intestines that can lead to cancer [5];
2. Red meat may promote chronic inflammation in the body, thereby increasing the risk of cancer;
3. Meats cooked at high temperatures, such as grilled and smoked meats (including chicken and seafood), produce heterocyclic amines and polycyclic aromatic hydrocarbons during the cooking process, which are carcinogens;
4. Processed meats often contain large amounts of fat and nitrites, which
not only produce carcinogens (such as nitrosamines) but may also lead to
weight gain, thereby increasing the risk of colorectal cancer.
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However, it is important to note that even though consuming red meat may increase the risk of certain cancers, the World Cancer Research Fund and the American Institute for Cancer Research do not recommend abstaining from meat entirely.
This is because the benefits of eating meat are also clear, as meat is an important source of high-quality protein, iron, zinc, and vitamin B12. By choosing lean meats, controlling your intake to no more than 350-500 grams per week (cooked weight), and reducing the consumption of processed meat products, one can lower the cancer risk associated with meat consumption.
Therefore, it is a misinterpretation to assert that eating meat will definitely cause cancer.
Even cancer patients need to eat meat. Due to the increased energy expenditure caused by surgery and radiotherapy, cancer patients' needs for protein and calories also increase accordingly, and meat can provide them with high-quality protein.
Evidence suggests that dietary fiber can reduce the risk of certain cancers, and vegetables, fruits, soy products, nuts, and other plant-based foods are the primary sources of dietary fiber [1].
In addition, the antioxidants and phytochemicals found in vegetables and fruits also protect cells. However, it would be incorrect to assume that a vegetarian diet will prevent cancer.
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At present, the idea that "a vegetarian diet prevents cancer" is not conclusively proven. Although a vegetarian diet may be healthier than a traditional diet that is high in animal products, there is currently no evidence to suggest that a vegan diet is more effective in preventing cancer than a balanced dietary pattern that is primarily plant-based with some animal products.
A 2018 report from the American Institute for Cancer Research also concluded that the current evidence is too limited to determine that a vegan diet significantly reduces the risk of cancer occurrence.
A vegetarian diet can also be unhealthy and increase the risk of cancer. If one frequently consumes fried vegetarian foods and often has refined grains and sugary beverages, the risk of cancer may actually increase.
For vegetarians who are overweight, obese, smokers, or have other unhealthy lifestyle habits, the rate of cancer will not be reduced simply by being vegetarian [6].
The World Cancer Research Fund/American Institute for Cancer Research has proposed some cancer prevention recommendations that are worth learning:
If your diet is mainly meat-based, to reduce the risk of cancer, you don't necessarily have to give up meat. Instead, you can add more plant-based foods to your diet.
For example, when preparing a meal, at least 2/3rds of the food should be vegetables, fruits, whole grains, and legumes; eat two fist-sized portions of fresh fruit daily; limit red meat intake to no more than 350-500 grams per week (cooked weight); add an extra serving of vegetables when eating meat; and consume less processed meats such as ham, hot dogs, deli meats, and bacon.
It is important to note that the above suggestions are for dietary combinations to reduce cancer risk. Reducing the risk of cancer does not mean you won't get cancer, so don't fantasize about preventing cancer by eating a certain food—currently, there is no evidence that any food can cure or prevent cancer.
In addition, talking about cancer prevention without considering external factors is also incomplete. To reduce the risk of cancer, a healthy lifestyle, a balanced diet, maintaining a normal weight, and exercising more are also very important external factors.
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Summary:
● Although consuming red meat may increase the risk of certain cancers, the benefits of eating meat are also evident. It is a misinterpretation to believe that eating meat will necessarily lead to cancer.
● There is no definitive conclusion that a vegetarian diet can prevent cancer, and an unhealthy vegetarian diet may increase the risk of cancer.
● Currently, there is no evidence to suggest that any specific food can cure or prevent cancer. To reduce the risk of cancer, it is also very important to maintain a healthy lifestyle, a balanced diet, an average weight, and exercise regularly.
Nutrition Consultant, Accredited Practicing Dietitian (APD), Registered Dietitian (RD)
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