Overconsumption of Hot-Natured Foods
Hot-natured foods refer, on one hand, to foods that are directly perceived as being too hot or scalding, and on the other hand, to foods classified as having a "hot" nature in Traditional Chinese Medicine (TCM). Because they are excessively pungent and heating, they can easily damage the epithelial cells of the digestive tract mucosa. Therefore, this type of food is most likely to induce tumors of the digestive system.
Overly hot diets are a major cause of esophageal cancer and other digestive tract tumors. Consuming food that is too hot damages and irritates the esophageal mucosal epithelium. Long-term irritation can induce malignant changes in the tissue. The incidence of digestive tract tumors is significantly higher among Chinese people than among Westerners, which is related to the Chinese preference for hot foods and for consuming hot soups with every meal, such as vegetable soups and noodle broths. In contrast, Western diets are generally simpler, with cold drinks like juice and cola being more common than hot soups.
Alcohol is considered a pungent and heating substance. Long-term alcohol consumption is one of the most common factors in the development of digestive system tumors. The southwestern region of Shandong is a high-incidence area for esophageal cancer, which is related to the local diet's preference for hot foods and alcohol. In fact, as early as 1964, the World Health Organization (WHO) concluded that the excessive consumption of alcoholic beverages is associated with oral cancer, laryngeal cancer, and esophageal cancer. In a study comparing Tongxing Township, a relatively high-incidence area for liver cancer in Qidong County, Jiangsu, with Xining Township, a relatively low-incidence area, it was found that the liver cancer mortality rate in the former was 2.5 times that of the latter. The two townships are separated by only a road, have similar natural environments, and comparable smoking rates. The difference was that people in the high-incidence area favored alcohol, while those in the low-incidence area preferred tea.
Foods that are fried, smoked, or grilled also belong to the category of "hot" foods in TCM. Because these foods are subjected to high-temperature frying and roasting, they also become "hot" in nature. Research has confirmed that long-term consumption of such foods can easily lead to stomach, intestinal, and liver cancers.
Just as Chinese people are fond of tea, Westerners generally prefer coffee. After five years of epidemiological investigation, American scholars concluded that caffeine has a certain effect on the development of pancreatic and bladder cancer. People who drink coffee regularly have a 2 to 3 times greater risk of developing these two types of cancer compared to those who do not. Among pancreatic cancer patients, at least half are attributed to excessive coffee consumption.
Imbalance of the Five Flavors
TCM posits that a diet should be balanced with the five flavors: sweet, bitter, sour, pungent, and salty. Overindulgence in any single flavor can lead to disease. In the factors that contribute to tumors, excessive consumption of rich, greasy foods and excessive saltiness are common causes.
Excessive Rich and Greasy Foods
In TCM, rich and greasy foods are those that are sweet and fatty. From a clinical perspective, sweet foods—namely starchy and sugary foods—when consumed in excess, can lead to stomach cancer. An excessive intake of high-fat foods like fatty meats and oils can promote breast cancer, colon cancer, rectal cancer, and pancreatic cancer. From a TCM perspective, tumors fall under the category of "accumulation syndromes." The *Neijing* (The Yellow Emperor's Inner Canon) states that accumulation syndromes are the stagnation of body fluids and blood stasis. Rich and greasy diets are known to generate dampness and phlegm, which undoubtedly exacerbates the accumulation of these pathological products.
From a modern medical perspective, a frequent diet high in fat can prompt the liver to secrete more bile. Once in the intestine, primary bile acids in the bile are converted into deoxycholic acid and lithocholic acid by anaerobic bacteria. Both of these substances are carcinogens that can cause intestinal mucosal cells to become cancerous. At the same time, fat can also provide a suitable growth environment for various tumors.
Excessive Saltiness
In addition to salt, salty foods also include pickled vegetables, salted fish, cured meats, and other preserved products. According to relevant research, the risk of developing esophageal cancer for those who frequently consume preserved foods is 2.79 times higher than for those who rarely eat them. A preference for salty foods most easily leads to stomach cancer. Japanese fishermen who are fond of salted fish have a high prevalence of stomach and esophageal cancer. A fondness for salted fish is also a significant factor in causing nasopharyngeal cancer. Researchers in Malaysia found that coastal residents have a higher incidence of nasopharyngeal cancer, which is related to their love of salted fish. National survey data in China show that in high-incidence areas of stomach cancer, the average daily salt intake is 50 grams per person, whereas in low-incidence areas, it is only about 6 grams.
In reality, salt itself is not carcinogenic. The cause of canceration is that high concentrations of salt solutions can easily destroy the protective layer of the gastric mucosa, causing erosion or ulcers. In such a state, once exposed to carcinogens, it can promote local canceration of gastric mucosal cells. Salt is an essential substance for the human body, but it should not be consumed in excess. It is generally recommended that the daily salt intake for a healthy person should be controlled to less than 6 grams.
Consumption of Denatured and Moldy Foods
Aflatoxin is widely recognized as the most potent carcinogen. Aflatoxin is abundant in moldy grains, corn, and peanuts. This fungus thrives in warm, humid environments, and studies have found it can induce various tumors in experimental animals. This factor is a major reason for the high incidence of cancer in some regions of Asia and Africa.
Preserved Foods
Nitrites are also recognized carcinogens. Large amounts of nitrites are produced when vegetables and fresh meat are preserved. Nitroso compounds are found in salted dried fish, fermented pickles, sauerkraut, overnight cooked cabbage, sausages, and meats. Regular consumption of these foods carries a risk of causing cancer.