各种饮食成分对维持健康、预防疾病相当重要。三大宏量营养素碳水化合物、蛋白质、脂肪不仅给机体供能，在肿 瘤营养代谢上也发挥重要作用。选择适量和优质的碳水化合物能降低肿瘤风险，提高优质蛋白质供给、高膳食纤维、高ω‐3多 不饱和脂肪酸的饮食，对改善肿瘤患者营养状况和预后有显著益处。不健康的膳食可使机体出现肠道菌群失调，产生有毒代 谢产物，诱导机体炎症和免疫失衡，促进肿瘤的发生。典型的西式饮食如进食较高含量的饱和脂肪酸、精制碳水化合物等会破 坏肠道屏障功能，导致肠道菌群失衡，增加肿瘤风险。以多蔬菜水果、多鱼虾水产品、经常吃奶类和大豆制品、适量的谷类和肉 禽类、烹调清淡少盐为主要特点的我国江南地区膳食模式代表东方健康膳食模式，值得倡导。遵循均衡营养、倡导合理膳食是 维持良好肠道微生态、防治肿瘤并降低全因死亡风险的关键。本文从营养素摄入和膳食模式对人体肠道微生态影响以及与肿 瘤发病及防治的角度展开论述。

Dietary components are important for maintaining health and preventing disease. The three major macronutrients including carbohydrates, protein and fat not only supply energy to the body, but also play an important role in tumor nutrition metabolism.Proper amount and high quality carbohydrates can reduce the risk of cancer, and improve the diet with high quality protein supply, high dietary fiber and high ω⁃3 polyunsaturated fatty acids, which has significant benefits to improve the nutritional status and prognosis of cancer patients. Unhealthy diet and other factors can cause intestinal flora imbalance in the body, produce toxic metabolites, induce inflammation and immune imbalance, and promote the occurrence of tumors.A typical Western diet high in saturated fatty acids and refined carbohydrates can disrupt the intestinal barrier,metabolism and nutrition of cancer and an increased risk of cancer. The dietary pattern in southern China, which is characterized by more vegetables and fruits, more fish and shrimp aquatic products, regular consumption of dairy and soybean products, moderate consumption of cereals and meat and poultry, light cooking and less salt, represents the healthy dietary pattern in the east and deserves to be advocated. Following the balanced nutrition and advocating the rational diet are the key to maintaining a good intestinal microecology，preventing and controlling cancers and reducing the risk of all⁃cause mortality. This review will summarize the effects of nutrients intake and dietary patterns on human intestinal microecology as well as the incidence and prevention of cancer.