One cup of soymilk (350 grams) contains about 6.3 grams of protein. The mass of a cup of soymilk is about 350 grams, and each 100 grams of soymilk contains about 1.8 grams of protein, so a cup of soymilk contains about 6.3 grams of protein. In addition, it also contains certain carbohydrates, fat and dietary fiber and other nutrients. Each 100 ml of unsweetened soymilk contains 16 calories, of which 1.1 g of carbohydrates, 0.7 g of fat, 1.8 g of protein, 1.1 g of dietary fiber, 15 micrograms of vitamin A, 48 milligrams of potassium, 10 milligrams of calcium, and 0.8 milligrams of vitamin E. Moderate consumption of soy milk is beneficial to health in the absence of allergies, and should not be consumed by those who are allergic to soy.