Refined grains, in contrast to whole grains, refers to grain products consisting of grains or grain flours that have been significantly modified from their natural composition. The modification process generally involves the mechanical removal of bran and germ, either through grinding or selective sifting. Further refining includes mixing, bleaching, and brominating; additionally, thiamin, riboflavin, niacin, and iron are often added back in to nutritionally enrich the product. Because the added nutrients represent a fraction of the nutrients removed, refined grains are considered nutritionally inferior to whole grains. However, for some grains the removal of fiber coupled with fine grinding results in a slightly higher availability of grain energy for use by the body. Furthermore, in the special case of maize, the process of nixtamalization (a chemical form of refinement) yields a considerable improvement in the bioavailability of niacin, thereby preventing pellagra in diets consisting largely of maize products.
| Wheat | Rice | |||||
|---|---|---|---|---|---|---|
| Whole | Refined | Enriched | Whole | Refined | Enriched | |
| Food energy | 100% | 107% | 107% | 100% | 99% | 99% |
| Carbohydrates | 100% | 105% | 105% | 100% | 104% | 104% |
| Fiber | 100% | 22% | 22% | 100% | 37% | 37% |
| Protein | 100% | 75% | 75% | 100% | 90% | 90% |
| Thiamin (B1) | 100% | 27% | 176% | 100% | 17% | 144% |
| Riboflavin (B2) | 100% | 19% | 230% | 100% | 53% | 53% |
| Niacin (B3) | 100% | 20% | 93% | 100% | 31% | 82% |
| Pantothenic Acid (B5) | 100% | 43% | 43% | 100% | 68% | 68% |
| Pyridoxine (B6) | 100% | 13% | 13% | 100% | 32% | 32% |
| Folate (B9) | 100% | 59% | 350% | 100% | 40% | 1155% |
| Vitamin E | 100% | 5% | 5% | 100% | 18% | 18% |
| Calcium | 100% | 44% | 44% | 100% | 100% | 100% |
| Iron | 100% | 30% | 120% | 100% | 54% | 293% |
| Magnesium | 100% | 16% | 16% | 100% | 17% | 17% |
| Phosphorus | 100% | 31% | 31% | 100% | 35% | 35% |
| Potassium | 100% | 26% | 26% | 100% | 52% | 52% |
| Sodium | 100% | 40% | 40% | 100% | 71% | 71% |
| Zinc | 100% | 24% | 24% | 100% | 29% | 29% |
| Copper | 100% | 38% | 38% | 100% | 79% | 79% |
| Manganese | 100% | 18% | 18% | 100% | 29% | 29% |
| Selenium | 100% | 48% | 48% | 100% | 65% | 65% |
Read more about Refined Grains: See Also
Famous quotes containing the words refined and/or grains:
“There might be a class of beings, human once, but now to humanity invisible, for whose scrutiny, and for whose refined appreciation of the beautiful, more especially than for our own, had been set in order by God the great landscape-garden of the whole earth.”
—Edgar Allan Poe (1809–1849)
“The millions of grains are black, white, tan, and gray,
and mixed with quartz grains, rose and amethyst.”
—Elizabeth Bishop (1911–1979)