Introduction: Recently, the claim that "bringing lunch to work is a cause of stomach cancer in young women" has been widely circulated. Some even say that "the risk of developing stomach cancer from eating leftover meals is 3.6 times higher," which has shocked many, causing them to say they will no longer dare to bring their own lunches.
Currently, many office workers have the habit of bringing their own lunches. They mostly prepare the food the night before, store it in the refrigerator, and bring it to their workplace the next day. According to the claim that "the risk of stomach cancer from eating leftover meals is 3.6 times higher," nitrates in food are converted into nitrites by bacterial decomposition, which are carcinogenic and cannot be removed by heating. Damage to the gastric mucosa can lead to gastric ulcers, atrophic gastritis, and even stomach cancer.
Stomach cancer is one of the most common malignant tumors in China, with its incidence rate ranking first among all types of cancer. The high incidence of stomach cancer caused by leftover meals has left many people who bring their own lunches at a loss: eating out is not only expensive but also raises concerns about hygiene. They bring lunch to eat healthier, but unexpectedly, it can also cause cancer.
In response, Wu Yongdong, Deputy Director and Chief Physician of the Digestive Department at Beijing Friendship Hospital, stated that current clinical observations show that the causes of stomach cancer are the result of multiple factors acting together over a long period. It is related to lifestyle, diet, environmental factors, genetic factors, and psychological factors. It is also associated with chronic gastritis, gastric polyps, gastric mucosal dysplasia, post-surgical residual stomach, and long-term Helicobacter pylori infection. A single risk factor is not enough to trigger cancer.
Clinical observations in recent years have shown that young and middle-aged stomach cancer patients are not uncommon. Especially among young people aged 19 to 35, the incidence of stomach cancer has doubled compared to the 1970s, which is indeed related to the dietary and lifestyle habits of young people. For example, many young people enjoy barbecue, hot pot, fried foods, staying up late, smoking, and drinking. Long-term unhealthy and irregular diets can damage the gastric mucosa, causing diseases such as gastritis and gastric ulcers. While it is not wrong to remind people to eat fewer leftover meals from a healthy eating perspective, stomach cancer absolutely cannot be explained by the single trigger of "leftover meals." Many factors have a greater negative impact on health than leftover meals. Currently, the following 5 factors are listed as high-risk factors for stomach cancer:
1. Long-term consumption of high-salt, smoked, and salt-preserved foods.
2. Eating quickly, loving very hot and spicy foods, and not eating three meals a day on time.
3. Suffering from atrophic gastritis, gastric ulcers, gastric polyps, intestinal metaplasia, pernicious anemia, or having a residual stomach after a partial gastrectomy, all of which carry a risk of cancerous changes.
4. A family history of the disease. The incidence rate of relatives of stomach cancer patients is 4 times higher than that of normal people. Genetic factors are the most significant risk factor for stomach cancer.
5. Individuals over 40 years old with long-term, untreated stomach ailments.
Director Wu Yongdong said that if food is stored in an environment of 0-4 degrees Celsius for no more than 20 hours, the possibility of spoilage is minimal. The likelihood of developing stomach disease from eating such a meal is so small it can be ignored. It's similar to when we travel by plane; radiation is inevitable, but the amount is not enough to cause disease.
Leftover meals should be eaten less, but it is not absolutely forbidden. Researchers from the Food Inspection Institute of the Product Quality Inspection and Research Institute of the Fujian Provincial Quality Supervision Bureau once tested bok choy, braised pork, braised fish, and rice stored in fresh-keeping boxes and refrigerated after being cooked, for storage times of half an hour, 4 hours, 9 hours, and 24 hours. The results showed that the nitrite content in all these meals was less than 1 mg/kg. The nitrite content in meat stored at room temperature for 4 hours was also below 1 mg/kg. The national limit for nitrite content is: 4 mg/kg for vegetables, 3 mg/kg for fresh meat, and 3 mg/kg for rice.
From a health perspective, leftover meals, especially leftover vegetables, not only have low nutritional value but are also prone to spoilage. All vegetables contain nitrates, with levels from highest to lowest being: petioles, leaves, stems, roots, flowers, tubers, bulbs, fruits, and seeds. This means that vegetables like beans, cucumbers, tomatoes, and onions have very low nitrate content, while vegetables like spinach, chives, and celery have relatively higher nitrate content and are more prone to spoilage. When leftover meals are contaminated, bacteria can multiply in large numbers, causing gastroenteritis and even food poisoning.
Director Wu Yongdong reminded that as the pace of life accelerates, many people have stomach problems, such as common atrophic gastritis. Some patients worry that atrophic gastritis will turn into cancer. In fact, only about 1% of patients may develop stomach cancer, and the possibility is slightly higher for autoimmune atrophic gastritis. Early-stage stomach cancer often has no symptoms or only minor ones, such as upper abdominal pain, loss of appetite, bloating, acid regurgitation, and sudden weight loss. When clinical symptoms are obvious, the disease is already in an advanced stage. Therefore, to detect the disease early, one should insist on regular health check-ups. For people over 40, an annual physical examination at a regular center is one of the effective prevention methods.
"Hidden hunger" can also lead to stomach cancer
Hong Zhongxin, Director of the Nutrition Department and Senior Nutritionist at Beijing Friendship Hospital, reminded that health is sustained by nutrition, and nutrition is sustained by life. Do not overlook the harm of "hidden hunger" to your health.
Many people think that with such good living conditions and abundant material goods, there is no problem with nutritional deficiency. In fact, "hidden hunger" still exists even in affluent conditions. Common manifestations include iron deficiency, iodine deficiency, zinc deficiency, vitamin A deficiency, and vitamin D deficiency. 70% of human chronic diseases are related to this.
Modern medical research shows that the human body needs no less than a hundred types of nutrients, which can be summarized into 7 categories: protein, fat, sugar, inorganic salts (minerals), vitamins, water, and fiber. Any substance that can maintain human health and provide the various materials needed for human growth, development, and labor is called a nutrient. "Hidden hunger" refers to a state where the body has a hidden need for nutrients due to an imbalance in nutrition, leading to a deficiency of certain vitamins and essential minerals while other components are excessively consumed.
Studies have shown that about 45% of cancers are related to nutritional factors. Modern people's dietary structures are unreasonable, with excessive intake of animal foods and fats, and low intake of cereals that are too refined. Frequent overtime and business trips, irregular eating habits, dieting to lose weight, and using snacks to replace meals are all related to inducing stomach cancer, colorectal cancer, colon cancer, breast cancer, etc. In the past, most stomach cancer patients were poor or elderly. Now, most stomach cancer patients are due to eating too well. Among stomach cancers, about 30% are cardia stomach cancers, which often appear in obese people with acid reflux. In the United States, Canada, and Australia, the most cases of cardia stomach cancer are caused by obesity or acid reflux.
Guidelines for Healthy Lunchboxes
1. It's best to cook the rice fresh in the morning. The storage time for leftover rice should be minimized to 5-6 hours, and it must be thoroughly heated before eating. Leftover rice is very likely to cause food poisoning, but most leftover rice looks normal, leading to carelessness.
2. After cooking the food, let it cool naturally before covering it with a lunchbox and putting it in the refrigerator. However, seafood, green leafy vegetables, and cold dishes are prone to spoilage overnight and are best not eaten the next day.
3. Keep the rice and dishes separate in the lunchbox to prevent bacterial growth.
4. It is recommended to use glass containers to reduce chemical reactions.
5. When preparing vegetables for the next day, cook them to about 60-70% done to prevent further destruction of their nutritional components when reheated in the microwave the next day.