An annual herb of Solanum in Solanaceae. Also known as potato, potato, yam egg, sweet potato (commonly known in Hong Kong and Guangzhou) and so on. Tubers are edible and are important crops for both food and vegetables. Some scholars believe that there are seven cultivated species of potato * * *, which are mainly distributed in temperate and subtropical areas in the Andes of South America and its nearby coastal areas. The most important potato cultivation species is tetraploid. The tetraploid cultivated potato spread all over the world. At first, the short-day type was introduced from Colombia in South America to Spain in Europe in 1570, and it became the long-day type through artificial selection. Later, it spread to Asia, North America, South Africa and Australia. Potato has high yield, rich nutrition and strong adaptability to the environment. Now it has spread all over the world, and tropical and subtropical countries can cultivate and obtain high yield even in winter or cool season. Potatoes, sweet potatoes, taro and other potato foods are rich in nutrients. The contents of protein, vitamin C, vitamin B 1 and vitamin B2 are much higher than those of apples, and the contents of calcium, phosphorus, magnesium and potassium are also very high, especially the content of potassium, which can be said to rank first among vegetables. Potatoes contain a lot of high-quality cellulose, which can prevent constipation and prevent cancer. So, how to eat potatoes to eat well? First of all, to ensure the quantity, eating potato food (potato, sweet potato, taro) every day should be about 80 grams. Secondly, the combination of meat and vegetables is good. As long as the combination is good, you can enjoy the food and achieve the goal of keeping slim. When eating potatoes, the intake of staple food should be reduced accordingly, which can be controlled according to the ratio of potatoes to staple food of 3 ∶1~ 4 ∶1. If you eat about 80 grams of potato food every day, it may help reduce the risk of stroke. For many mashed potatoes and French fries in fast food, they are oxidized during processing, which destroys a lot of vitamin C and greatly reduces the nutritional components. For French fries, it is easy to increase the intake of fat, and it is difficult to judge whether the oil of French fries is fresh. In addition, repeated high-temperature heating produces polymers, such as toxic cyclic monomers, which are carcinogens, so eat as little as possible. Nutritionists point out that eating potatoes does not need to worry about excess fat, because it only contains 0.1%fat, which is the least among all hunger foods. Eating more potatoes every day can reduce fat intake and gradually metabolize excess fat. However, it is worth noting that potatoes, especially potatoes, contain a toxic substance called alkaloids, which can cause poisoning, nausea, diarrhea and other reactions when ingested in large quantities. The alkaloids in potatoes belong to steroid glycoside alkaloids, mainly solanine and solanine. Its structure is similar to human steroid hormones, such as androgen, estrogen and progesterone. According to foreign reports, the newly harvested potato alkaloids are 20 ~ 80 mg per kilogram, and after storage for a period of time, they rise to 75 ~114 mg. The alkaloid content of sprouted or moldy potatoes will further increase. This toxic compound has a higher content in potato skin, so it is necessary to peel it when eating, especially to peel off the green skin. In addition, potatoes with buds are more toxic. When eating, you must dig out the buds and roots and soak them in clear water. Stewing and cooking should be on fire. In addition, if pregnant women often eat potatoes with high alkaloid content, accumulation in the body may lead to fetal malformation. Of course, there are considerable individual differences among people, and not everyone will have abnormalities after eating potatoes. However, it is better for pregnant women not to eat or eat less potatoes, especially potatoes that have been stored and germinated for a long time, which is especially important for women in the early pregnancy. Species name: Dioscorea oppostia. Other names: Dioscorea opposita, Dioscorea opposita, Dioscorea opposita, Dioscorea opposita, Dioscorea opposita, Dioscorea opposita, Dioscorea opposita, Dioscorea opposita, sweet potato, sweet potato and Yuyan. Smell: (root) sweet, warm, flat and nontoxic. Nutritional analysis 1. Strengthening the spleen and benefiting the stomach, helping digestion: Yam contains amylase, polyphenol oxidase and other substances, which is beneficial to the digestion and absorption function of the spleen and stomach, and is a dual-purpose product for nourishing the spleen and stomach. Both spleen yang deficiency and stomach yin deficiency can be eaten. Clinically, it is commonly used to treat spleen and stomach weakness, anorexia, fatigue, diarrhea and other diseases; 2. Nourishing the kidney and replenishing essence: Yam contains a variety of nutrients, which has the functions of strengthening the body and nourishing the kidney and replenishing essence. Generally, symptoms such as nocturnal emission due to kidney deficiency, frequent urination, etc. can be taken; 3. Benefiting lung and relieving cough: Yam contains saponin and mucus, which has the function of lubrication and moistening, so it can benefit lung qi, nourish lung yin and treat lung deficiency, phlegm and cough for a long time; 4. Lowering blood sugar: Yam contains mucin, which can lower blood sugar.