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'Refined grains', in contrast to whole grains, refers to grain products comprised 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 endosperm, 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^[1]. However, the removal of fiber coupled with fine grinding results in a considerably higher availability of grain energy for use by the body^[2]. 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 comprised largely of maize products.

'Table 1. Effects of Refining and Enrichment on Wheat and Rice.'^[3]

	Wheat			Rice
	Whole	Refined	Enriched	Whole	Refined	Enriched
Calories	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%

Contents

See Also

External Links

Sources

See Also

★ Whole grain

★ Flour

★ Whole wheat flour

External Links

★ ''The History of Bread'', UK Bakers Federation, 2002

★ ''Exposing the Deception of Enrichment'', The Bread Beckers, 2003

Sources

1. Campbell, Hauser & Hill, ''Nutritional Characteristics of Organic, Freshly Stone-Ground, Sourdough & Conventional Breads'', McGill University, 1991
2. Goodband, Tokach & Nelssen, ''The Effects of Diet Particle Size on Animal Performance'', Kansas State University, 1995
3. USDA Standard Reference 17 Food Nutrient Database