2.3.1.1 Supplementing the supply of nutrients in the human body to strengthen health and prevent diseases. For example, eating animal livers can nourish the liver and prevent night blindness; ingestion of kelp can not only supplement iodine and vitamin, but also prevent goiter; intake of fruit and fresh vegetables can supplement nutrition and prevent scurvy, etc. Besides, the special effects of certain food may be directly utilized to prevent certain diseases. For instance, garlic is used to prevent affection by exopathogen and diarrhea; green gram soup is applied to prevent summer-heat; Congbai (Bulbus Allii Fistulosi) and Shengjiang ( Rhizoma Zingiberis Recens ) are adopted to prevent common cold due to invasion by wind, etc.
    2.3.1.2 Prolonging life, resisting and preventing ageing. Many types of food have the anti-ageing actions, such as sesame, mulberry, Gouqizi ( Fructus Lycii ), Guiyuanrou (Arillus Longan ), Hutao (Semen Juglandis), bee milk, Huaishanyao (Rhizoma Dioscoreae), human milk, milk, soft-shelled turtle, the regular ingestion of which is beneficial to health and longevity.