Sweet potato, also known as sweet potato, sweet potato, sweet potato and sweet potato, is an annual plant of convolvulaceae. It is a kind of health food with dual functions of medicine and food. Sweet potato contains dietary fiber, carotene, vitamins A, B, C and E, and more than ten kinds of trace elements such as potassium, iron, copper, selenium and calcium. The nutritional value is very high, and it is called nutrition by nutritionists. Professor Zhang from the Health Room of Beijing University of Chinese Medicine said that eating sweet potatoes will not only make you fat, but also help you lose weight, keep fit, prevent sub-health, and relieve constipation and detoxify. Every100g of fresh sweet potato contains only 0.2g of fat, which generates 99 kilocalories of heat energy, about one third of that of rice. It is a good low-fat and low-calorie food, at the same time, it can effectively prevent sugar from transforming into fat, which is beneficial to weight loss and fitness. Sweet potato contains a lot of dietary fiber, which cannot be digested and absorbed in the intestine. It can stimulate intestinal tract, enhance peristalsis, relieve constipation and detoxify, especially for senile constipation. Zhang particularly emphasized that sweet potato is an alkaline food and the most rare, just like many fruits and vegetables. Generally, food is acidic, and the PH value of human body is 7.34, so eating sweet potato is beneficial to the acid-base balance of human body. Eating sweet potato can reduce blood cholesterol and prevent "modern diseases" such as sub-health, cardiovascular and cerebrovascular diseases. Professor Lin Hongsheng, director of the Oncology Department of Guang 'anmen Hospital of China Academy of Traditional Chinese Medicine and deputy director of the National Center for Oncology of Traditional Chinese Medicine, said that sweet potato is not only nutritious, but also ranks first among anti-cancer foods. There are many introductions in this document. The list of 20 kinds of anticancer vegetables published by National Cancer Research Center of Japan is: sweet potato, asparagus, cauliflower, cabbage, broccoli, celery, sweet pepper, carrot, cauliflower, amaranth, shepherd's purse, kohlrabi, mustard, tomato, green onion, garlic, cucumber and Chinese cabbage, among which sweet potato ranks first. Japanese doctors found that the cancer inhibition rate of cooked sweet potatoes was higher than that of raw sweet potatoes through a dietary survey of 260 thousand people. Medical workers in China investigated the hometown of centenarians in western Guangxi, and found that all the longevity elders here have a common feature, that is, they are used to eating sweet potatoes every day, even taking sweet potatoes as their staple food. The anticancer mechanism of sweet potato is not very clear, and opinions vary. The hospital in Philadelphia, USA, extracted an active substance-androsterone from sweet potato, which can effectively inhibit the occurrence of colon cancer and breast cancer. Another American university study found that there is a substance called dehydroepiandrosterone in sweet potato, which has a definite effect on cancer prevention and treatment. Professor Zhang from the Health Room of Beijing University of Chinese Medicine believes that sweet potato has a certain anti-cancer effect, but its anti-cancer "ability" should not be exaggerated and should be treated dialectically, because its mechanism of action has not been fully clarified, and its greatest function should be to lose weight, build up health, prevent sub-health, and relieve constipation and detoxify. Regarding the anti-cancer effect, Chinese medicine theory holds that it can reduce the accumulation of garbage and toxins in the human body because of its catharsis and detoxification. In this regard, Professor Song Santai, director of the Cancer Center of China Academy of Military Medical Sciences and deputy director of the Cancer Committee of the whole army, also believes that the mechanism and reasons of sweet potato anti-cancer have not yet been scientifically tested. Theoretically, it is speculated that it is rich in dietary fiber, which can moisten the intestines and relieve constipation, and roast sweet potatoes after treatment, which is beneficial to prevent cancers such as colon cancer. Eating sweet potatoes correctly is also very important. Be sure to pay attention to steaming and cooking thoroughly, because the cell membrane of starch in sweet potato is difficult to digest without being destroyed by high temperature, and the gasification enzyme in sweet potato will cause discomfort after eating; Excessive or unreasonable consumption of sweet potato can cause abdominal distension, heartburn, pantothenic acid, stomachache and so on. So you shouldn't eat too much. It should be used with caution for those diagnosed by TCM as dampness blocking the spleen and stomach, qi stagnation and blood stasis. According to ancient documents such as Compendium of Materia Medica and Addendum to Compendium of Materia Medica, sweet potato has the effects of "tonifying deficiency and benefiting qi, strengthening spleen and stomach, and strengthening kidney yin", which makes people "live longer and have fewer diseases". It can also tonify the middle energizer, promote blood circulation, warm the stomach and nourish the five internal organs. "Contemporary Chinese Medicine" said: "Sweet taste, flat nature. Into the spleen and kidney. " , "tonify the middle and blood, replenish qi and be holy, broaden the stomach and relax the bowels. Indications: Spleen edema, sore and swelling, intestinal dryness and constipation. Sweet potato is the first choice for anti-cancer food. Recently, medical workers in China conducted a survey on the hometown of centenarians in western Guangxi, and found that all the longevity elders here have a common feature, that is, they are used to eating sweet potatoes every day, and even take sweet potatoes as their staple food. Coincidentally, the list of 20 anti-cancer vegetables recently published by the National Cancer Research Center of Japan is: sweet potato, asparagus, cauliflower, cabbage, broccoli, celery, pumpkin, sweet pepper, carrot, cauliflower, amaranth, shepherd's purse, kohlrabi, mustard, tomato, green onion, garlic, cucumber and Chinese cabbage. Japanese doctors found that the cancer inhibition rate of cooked sweet potatoes (98.7%) was slightly higher than that of raw sweet potatoes (94.4%) through a dietary survey of 260,000 people. The hospital in Philadelphia, USA also extracted an active substance-androsterone from sweet potato, which can effectively inhibit the occurrence of colon cancer and breast cancer. Sweet potato is rich in essential nutrients such as starch, vitamins and cellulose, as well as mineral elements such as magnesium, phosphorus and calcium and linoleic acid. These substances can maintain the elasticity of blood vessels and are very effective in preventing and treating habitual constipation in the elderly. Unfortunately, most people think that eating sweet potatoes will make people fat and dare not eat them. In fact, on the contrary, sweet potato is an ideal diet food, its calorie is only 1/3 of that of rice, and because it is rich in cellulose and pectin, it has the special function of preventing sugar from transforming into fat.