Cancer, or malignant tumor, has become one of the most common fatal diseases. There are about 11 million new cancer cases in the world every year, and new cancer cases in China account for 20.3% each year. It has always been a major public enemy threatening health. The occurrence of cancer is closely related to factors such as genetics, environmental pollution, bad habits, dietary nutrition, viral infections and radiation. The most common cancers in men are: lung cancer, stomach cancer, liver cancer, and esophageal cancer; in women are: breast cancer, esophageal cancer, stomach cancer, lung cancer, liver cancer, and cervical cancer. The global incidence of cancer is generally on the rise. Cancers that have increased significantly include lung cancer, breast cancer, and colorectal cancer; cancers that have decreased significantly include gastric cancer and cervical cancer.
Cancer is caused by the proto-oncogenes of normal cells being activated by mutagens and transformed into uncontrolled abnormal cells. The new tissue produced by the abnormal proliferation of these cells does not have the function of normal tissue. Its main activity is to continuously consume the body’s resources, squeeze space and divide and proliferate more and more rapidly. The hyperplastic tissue is also called “tumor.” Cancer generally refers to malignant tumors. Cancer cells will break away from the malignant tumors and transfer to other organs through the blood and lymphatic system to form new tumors.
The principle of cancer control is “prevention first, combined prevention and treatment, early detection, early diagnosis and early treatment,” because one-third of cancers are preventable. We can see two key points from the process of cancer formation: one is mutagens, or carcinogens; the other is the monitoring of abnormal cells.
What role can probiotics play in the two key points of cancer prevention? First, let’s look at the formation or source of carcinogens. The 10 trillion bacteria in the intestines form a small chemical factory. Among them, harmful bacteria decompose digested food and other substances in the body into many carcinogens, the most common ones are nitrosamines, indole, phenols, and bile acids. We also ingest foods containing some pre-carcinogens and carcinogens (mainly pickled, smoked, roasted, and fried).
How do probiotics deal with them? First, probiotics can inhibit carcinogens and pre-carcinogens by binding, blocking or removing. It can also inhibit the activity of bacteria and invertase that may convert pre-carcinogens into carcinogens. To put it simply, probiotics can absorb carcinogens and process or transfer carcinogens, reducing their toxicity. Probiotics can help the body stay away from harmful bacteria and harmful enzymes, so they have no chance of processing carcinogens. The most typical example is that probiotics can reduce the activity of stool enzymes and effectively prevent colon cancer. Second, probiotics can acidify the intestines and regulate the intestinal flora, thereby reducing the number of harmful bacteria and changing the solubility of bile. Reduce the conversion of bile to the secondary bile acid of carcinogens. Third, probiotics can promote intestinal peristalsis and accelerate the excretion of harmful carcinogens in feces.
For the second key point, probiotics also have a certain effect on abnormal cells. First, probiotics can activate the immune system and improve the immune response. Once the human body has abnormal cells, the immune system will quickly detect it, and then an immune response will occur. Tumor necrosis factor, interleukin and interferon produced by immune cells are all weapons against tumors. Second, probiotics can produce compounds that inhibit the growth of cancer cells, such as some functional glycopeptides. Third, probiotics can produce anti-mutation substances and block the attack of harmful cells, inhibit the transformation of abnormal cells, and play a role in preventing cancer.
In fact, many mechanisms of probiotics in preventing and treating tumors are not very clear, and further research is still in progress. In 2007, the American Journal of Clinical Nutrition reported the conclusion of the clinical experiment of Ian Rowland, professor of human nutrition at the University of Northern Ireland: Drinks containing probiotics can reduce the possibility of genetic damage to intestinal cells and help prevent colon cancer. Other studies have shown that probiotics can reduce the risk of bladder cancer. Due to the direct connection with the digestive tract, probiotics have obvious relevance to digestive tract cancers.