Last week I made a trip to Issan, the Northeast of Thailand, and found many new vegetables, fruits and foods to write about. In this post I’ll present you the manthet or sweet potato, a crop which didn’t originate in Thailand and Asia, but can be found today in every part of the country. The sweet potato originated in Central or South America, and was brought to the Philippines and mainland Southeast Asia by the Spaniard and Portuguese. Today Asia is the biggest producer of the root crop, with China, its biggest promoter, producing over a 100 million tonnes on almost 50 000 km2, followed by Indonesia, Vietnam, Japan and the Philippines. On the other hand, Thailand kind of missed the sweet potato boom and its commercial production and yields are far below its neighbors (I didn’t find out why the commercial production of sweet potatoes failed and the yield were so low, comments are welcomed). Nevertheless, Thai farmers grew the manthet for many generations for domestic consumption and the root crop is considered an important component of many Thai dishes. The root vegetables are boiled, steamed, fried and added to curries, soups or desserts. Thai people distinguish the sweet potato, which is only distantly related to the common potato, in two different varieties: The light one called manthet si kaaw and the purple one called manthet si muang. Sweet potatoes are considered very healthy foods. They contain a lot of beta-carotene, and important antioxidant, vitamin A, which is good for the eyes and vitamin B6, which strengthens functions of the brain. Sweet potatoes are also rich in vitamin C, iron, magnesium, calcium and zinc. The root vegetable stabilize blood sugar level, which makes it an appropriate food for diabetics. They lower bad cholesterol levels (LDL) and contain components which help to relieve asthma and cure bronchial diseases. The crop is rich in carbohydrates, starch and proteins and has a low fat content, which makes it an ideal staple food.