Grains come in many shapes and sizes, from large kernels of popcorn to small quinoa seeds. Also called cereals, grains are the widely varied seeds of grasses, which are cultivated for food.
All types of grains are good sources of complex carbohydrates, various vitamins and minerals and are naturally low in fat. But grains that haven't been refined — called whole grains — are even better for you. Whole grains are better sources of fiber and other important nutrients, such as selenium, potassium and magnesium.
Anatomy of a whole grain
Grains are the seeds of plants. When whole, they include the bran, germ and endosperm — all of which contain valuable nutrients.
* Bran. Forming the outer layer of the seed, the bran is a rich source of niacin, thiamin, riboflavin, magnesium, phosphorus, iron and zinc. The bran also contains most of the seed's fiber.
* Germ. The part from which a new plant sprouts, the germ is a concentrated source of niacin, thiamin, riboflavin, vitamin E, magnesium, phosphorus, iron and zinc. The germ also contains protein and some fat.
* Endosperm. Also called the kernel, the endosperm makes up the bulk of the seed. It contains most of the grain's protein and carbohydrates and has small amounts of vitamins and minerals.
Whole grains vs. refined grains
Whole grains haven't had their bran and germ removed by milling, making them better sources of fiber — the part of plant-based foods that your body doesn't digest. A high-fiber diet can help lower your risk of heart disease, cancer and diabetes. A high-fiber diet may also lower your risk of other disorders, such as hemorrhoids, irritable bowel syndrome and the development of small pouches in your colon (diverticular disease).
Refined grains, such as white rice or white flour, have both the bran and germ removed from the grain. Although vitamins and minerals are added back into refined grains after the milling process, they still don't have as many nutrients as whole grains do, and they don't provide as much fiber.
You can eat whole grains plain, add them to other dishes or use them as ingredients in baked goods. Rice, bread, cereal, flour and pasta are all grains or grain products. Choose the whole-grain versions — rather than refined grains — as often as possible.