Eating walnuts often has many advantages: walnuts, also known as walnuts, are listed as the four largest dried fruits in the world alongside almonds, cashews and hazelnuts in the international market. Its footprints are almost all over the world, mainly in America, Europe and many parts of Asia. Its output is in addition to the United States, that is, China. Walnut is called "Hercules food", "nutritious nut" and "educational fruit" abroad. In China, it enjoys the reputation of "Long live the child", "longevity fruit" and "treasure for nurturing people". Its outstanding brain-nourishing effect and rich nutritional value are praised by more and more people. Walnut belongs to the dried fruit of deciduous trees in Juglandaceae. Walnut has a long history of cultivation in China. In the Natural History written by Zhang Hua in the 3rd century BC, it was recorded that "when Zhang Qian went to the Western Regions, he had to return walnut seeds". Walnut's hometown is Iran in the west of Asia, and it was introduced to China when Korea and Zhang Qian went to the Western Regions. Today, walnuts are distributed all over China. For a long time, the working people in China have carefully cultivated many new varieties of high-quality walnuts by using the common and wild walnut resources in China. If classified by origin, there are Chencang walnut and Yangping walnut; According to maturity classification, there are summer walnuts and autumn walnuts; According to the smoothness of the shell, there are light walnuts and hemp walnuts; According to the thickness of the shell, there are thin-shell walnuts and thick-shell walnuts. There are many excellent varieties of walnuts in China, such as "Shimen Walnut" in Hebei, which is characterized by fine grains, thin skin and sweet taste. The kernel yield is about 50% and the oil yield is as high as 75%, so it has the reputation of "Shimen Walnut is the treasure of the world". The paper walnut in Kuqa, Xinjiang, is called "Kekeyi" by Uighurs, which means the shell is thin and the oil content reaches 75%. This variety bears fruit quickly, and the masses describe it as "one-year-old, two-year-old and three-year-old walnuts hanging in baskets". Walnuts in Fenyang, Xiaoyi and other places in Shanxi are famous for their thin skin, full kernel and tender meat. The walnut skin in Qinling area of Shaanxi Province is as thin as an egg shell, commonly known as "egg-skinned walnut". The best variety is "Mian Walnut", with thin skin and thick flesh. Hold two walnuts in your hand, and with a little force, the walnut skin will break. In addition, the small walnuts produced in Hangzhou are also very popular with southerners. Walnut has high medicinal value and is widely used in traditional Chinese medicine. Chinese medicine believes that walnuts are warm, sweet and non-toxic, and have the effects of invigorating the stomach, enriching the blood, moistening the lungs and nourishing the mind. "Shen Nong Ben Cao Jing" lists walnuts as the top grade for long-term service, benefiting qi and prolonging life. In the Herbal Medicine of Dietotherapy written by Meng E in Tang Dynasty, it is recorded that eating walnut kernel can increase appetite, moisten blood vessels and make flesh and blood delicate. In the Song Dynasty, Liu Han and others recorded in Kaibao Materia Medica that walnut kernel "makes it fat and healthy, moistens muscles, has black beard and black hair, eats more diuretics and removes five hemorrhoids." According to the Compendium of Materia Medica written by Li Shizhen in the Ming Dynasty, walnut kernel has the effects of "benefiting qi and nourishing blood, moistening dryness and resolving phlegm, benefiting qi and promoting fluid production, treating triple energizer, warming lung and moistening intestine, treating deficiency cold, asthma and cough, severe pain in waist and feet, hernia in the heart, blood dysentery and intestinal wind". Modern medical research believes that phospholipids in walnuts have a good health care effect on brain nerves. Walnut oil contains unsaturated fatty acids, which can prevent and treat arteriosclerosis. Walnut kernel contains zinc, manganese, chromium and other indispensable trace elements. The contents of zinc and manganese are decreasing in the process of aging, and chromium can promote glucose utilization, cholesterol metabolism and protect cardiovascular system. The effect of walnut kernel on relieving cough and asthma is also very obvious. Winter has excellent curative effect on patients with chronic bronchitis and asthma. It can be seen that eating walnuts regularly can not only strengthen the body, but also resist aging. Some people often take tonics. In fact, it is really good to eat a few walnuts every morning and evening, which is often better than taking tonic. Walnuts are a good diet. Whether it is used for dispensing medicine, raw, boiled, dipped in sugar or cooked, it has good effects of enriching blood and benefiting qi, tonifying kidney and replenishing essence, relieving cough and asthma, moistening dryness and relaxing bowels. There are many ways to eat walnuts. Boiling walnuts with proper salt water and eating dregs can cure lumbago due to kidney deficiency, nocturnal emission, impotence, forgetfulness, tinnitus and frequent urination. Cooking porridge with walnuts, coix seed and chestnuts can cure frequent urination, nocturnal emission, loose stool and diarrhea. Eating walnuts, sesame seeds and lotus seeds dipped in sugar can nourish the heart and brain and cure night sweats. Eating raw walnuts, longan pulp and hawthorn can improve heart function. Walnut is also widely used to treat neurasthenia, hypertension, coronary heart disease, emphysema and stomachache.