Oat bran consists of only the bran of the oat seed, while rolled oats are made when whole grain oats, or groats, are pressed between rollers. Commonly served as hot cereal, both contain many important nutrients.
Groats can also be eaten, but they have a long cooking time, some consider them too chewy. Steaming and then rolling oats results in flakes that have a quicker cooking time and are a bit easier to eat.
Both oat bran and rolled oats contain a large amount of dietary fiber, though oat bran has slightly more fiber than rolled oats. Fiber adds bulk to the diet and helps control cholesterol and blood glucose levels. Both are also rich in carbohydrates, protein and B vitamins, which support the nervous system. Oat bran has more B vitamins than rolled oats. Both rolled oats and oat bran are unusual for plant foods because they are fairly high in iron, which is usually more abundant in animal protein. However, oat bran and rolled oats lack cholesterol, which is almost always found in animal products. Only moderate levels of fat are found in oat brain and rolled oats, and both are low in potentially dangerous saturated fat. They also have significant amounts of phosphorus, zinc, copper, manganese and selenium.