Why steaming is the healthiest way to cook?

Many of the vitamins and minerals found in fresh produce are lost with some conventional methods of cooking. Steaming ensures that vitamins such as vitamin B, riboflavin, thiamine, niacin, biotin, B12, pantothenic acid, and vitamin C, as well as minerals such as calcium, phosphorous, potassium, and zinc are retained. Steaming is a low-temperature cooking method (Under 212F) that is different from conventional high-temperature cooking (350F~600F) such as grilling, baking, frying, and roasting. High-temperature cooking often creates cancer-causing compounds: Heterocyclic aromatic amines (HAAs) and advanced glycation end products (AGEs). This alphabet soup of chemicals can damage human DNA and possibly initiate or further the progression of cancer. Steaming is a moist heat cooking method that can help reduce inflammation and promote healing. 

Another big advantage of steamed food is that it is less likely to cause bloating and constipation. Fried, grilled, and roasted foods are often associated with those problems.