When it comes to tumor, everyone will be afraid, so how to prevent tumor? It is to eat alkaline food often to prevent the accumulation of acidic waste, because an acidified body fluid environment is a fertile soil for normal cells to become cancerous, and adjusting the acid-base balance of body fluid is an effective way to prevent cancer. Here is a brief introduction of what are alkaline foods. The acidity and alkalinity of food refers to whether the inorganic salts in food are acidic or alkaline. The acidity and alkalinity of food depends on the ratio of the type and amount of minerals contained in food: potassium, sodium, calcium, magnesium and iron show alkaline reaction after entering the body; phosphorus, chlorine and sulfur show acidity after entering the body. Weakly alkaline foods include: tofu, peas, soybeans, green beans, rape, celery, sweet potatoes, lotus root, onions, eggplant, pumpkin, cucumber, mushrooms, radish, milk, etc. And alkaline foods are: spinach, cabbage, cabbage, lettuce, carrots, bamboo shoots, potatoes, kelp, citrus, watermelon, grapes, bananas, strawberries, corn, persimmons, coffee, wine, etc. To determine whether a food is acidic or alkaline, you can refer to the amount of calcium and phosphorus in the food to determine, and those with more calcium are alkaline, while those with more phosphorus are acidic. Generally speaking, good food is generally acidic, such as fish, meat, rice, wine, sugar, etc. All of them are acidic food. On the contrary, alkaline food such as seaweed, vegetables, white radish, tofu, etc. are mostly not easy to cause appetite but are good for the body. In addition to various kinds of livestock and poultry, common acidic foods include egg yolk, fish roe, oyster, white rice, noodles, bread, steamed fish, octopus, etc. Food acidity and alkalinity can be judged by the following: Strongly acidic foods: egg yolk, cheese, desserts, white sugar, tuna, halibut. Medium acidic food: ham, bacon, chicken, pork, eel, beef, bread, wheat. Weakly acidic foods: white rice, peanuts, beer, seaweed, octopus, chocolate, hollowed out flour, green onion. Strongly alkaline foods: grapes, tea, wine, kelp, citrus, persimmons, cucumbers, carrots. Medium alkaline foods: soybeans, tomatoes, bananas, strawberries, egg whites, dried plums, lemons, spinach, etc. Weakly alkaline foods: red beans, apples, collard greens, tofu, cabbage, rape, pears, potatoes. Alkaline foods are mainly divided into: vegetables and fruits; seaweeds; nuts; sprouted cereals and beans. To avoid or reduce the intake of the following acidic foods: starch; animal food; sweets; in the consumption of food to pay attention to the balance of acidity and alkalinity is the most beneficial to the body.