Study Reviews Healthy Benefits of Whole Grains

by | Apr 20, 2011 | 2004, Blood Pressure, Blood Sugar, Cardiovascular Health, Diabetes

Written by Greg Arnold, DC, CSCS. Research has suggested that whole grains can significantly benefit blood sugar and blood vessel health. 

With the advent of agriculture 10,000 years ago, whole grains became part of the human diet (1) but only over the last 3,000–4,000 years has a majority of the world’s population relied upon whole grains as a main component of the diet.   While “whole grain foods” include wheat, rice, maize, oats, rye, and millet, the most commonly consumed grain in the US is wheat (66-75% of total grain consumption).

The industrial revolution changed the way grains were processed. In 1873, the invention of the roller mill separated the 3 components of a whole grains (bran, germ, endosperm) and made it possible to use refined flour products. This caused the “dramatic decline” in whole-grain consumption seen between 1870 and 1970 (1). For a food to be considered a “whole grain”, it must include 51 % whole grain flour by weight of final product and must contain 1.7 g dietary fiber.

With nutrients that range from B-vitamins to minerals to amino acids and phytochemicals (4) it’s no wonder the health benefits of whole grains have been known since the time of Hippocrates (300’s BC). Whole grains have been recommended by Americans physicians in the 1800’s and mid 1900’s to help with constipation, culminating in the ‘fiber hypothesis’ of the 1970’s (5). In 1999, the FDA issued a health claim for whole grains, stating “Diets rich in whole grain foods…may help reduce the risk of heart disease and certain cancers.” (6). The FDA then broadened the health claim to include brown rice (7).

The research has suggested that whole grains can significantly benefit blood sugar and blood vessel health. Whole grains have consistently been shown to help decrease the risk for type 2 diabetes (8) which affects more than 24 million Americans and costs our healthcare system $174 billion each year (9). The evidence has been so convincing that whole grains are now recommended by the American Diabetes Association for DM prevention (10).

For cardiovascular disease, which affects 81 million Americans, causes 1 in 3 of all U.S. deaths and cost our healthcare system $503 billion in 2010 (11), a 2002 study (12) found “enough evidence exists that wholegrain products may reduce the risk of coronary heart disease” while a 2001 study (13) found oat and what cereals to help maintain blood vessel relaxation after high-fat meals. Finally, wholegrain oat cereal helped maintain healthy blood pressure and reduce the need for antihypertensive medications (14).

Despite these health benefits, Americans consume far less than the recommended three servings of whole grains on a daily basis. A 2000 study (15) found total grain intake was 6·7 servings/d among Americans 20 years and older, but only 1 of these servings being from whole grain and only 8% of the participants consuming the recommended three servings of whole grains per day. Finally, a 2003 study of US children and teenagers reported that their consumption of whole grains was less than one serving per day (16).

Source: Slavin, Joanne. “Whole grains and human health.” Nutrition research reviews 17.01 (2004): 99-110.

© The Authors 2004

Posted April 20, 2011.

References:

  1. Spiller GA (2002) Whole grains, whole wheat, and white flours in history. In Whole-Grain Foods in Health and Disease, pp. 1–7 [L Marquart, JL Slavin and RG Fulcher, editors]. St Paul, MN: Eagan Press.
  2. Slavin JL, Jacobs D & Marquart L (2001a) Grain processing and nutrition. Critical Reviews in Biotechnology 21, 49–66.
  3. Fulcher RG & Rooney Duke TK (2002) Whole-grain structure and organization: implications for nutritionists and processors. In Whole-Grain Foods in Health and Disease, pp. 9–45 [L Marquart, JL Slavin and RG Fulcher, editors]. St Paul, MN:Eagan Press.
  4. Miller G, Prakash A & Decker E (2002) Whole-grain micronutrients. In Whole-Grain Foods in Health and Disease, pp. 243–258 [L Marquart, JL Slavin and RG Fulcher, editors]. St Paul, MN: Eagan Press.
  5. Trowell H (1972) Ischemic heart disease and dietary fiber. American Journal of Clinical Nutrition 25, 926–932.
  6. “Health Claim Notification for Whole Grain Foods- posted on the US Food and Drug Administration website.
  7. FDA Approves Health Claim for Brown Rice, Confirms popular whole grain may provide protection against heart disease and certain cancers” posted May 8, 2008 on The USA Rice Federation website.
  8. Van Dam RM, Grievink L, Ocke MC & Feskens EJM (2003) Patterns of food consumption and risk factors for cardiovascular disease in the general Dutch population. American Journal of Clinical Nutrition 77, 1156–1163.
  9. Number of People with Diabetes Continues to Increase” from the CDC Website.
  10. Franz MJ, Bantle JP, Beebe CA, Brunzell JD, Chiasson JL, Garg A, Holzmeister LA, Hoogwerf B & Mayer-Davis E (2002) Evidence-based nutrition principles and recommendations for the treatment and prevention of diabetes and related complications. Diabetes Care 25, 148–198.
  11. “Cardiovascular Disease At A Glance: 2010”: – 11. Posted on the Centers for Disease Control website.
  12. Truswell AS (2002) Cereal grains and coronary heart disease. European Journal of Clinical Nutrition 56, 1–14.
  13. Katz DL, Nawaz H, Boukhalil J, Chan W, Ahmadi R, Giannamore V & Sarrel PM (2001) Effects of oat and wheat cereals on endothelial responses. Preventive Medicine 33, 476–484.
  14. Pins JJ, Geleva D, Leemam K, Frazer C, O’Connor PJ & Cherney LM (2002) Do whole-grain oat cereals reduce the need for antihypertensive medications and improve blood pressure control? Journal of Family Practice 51, 353–359.
  15. Cleveland LE, Moshfegh A, Albertson A & Goldman J (2000) Dietary intake of whole grains. Journal of the American College of Nutrition 19, 331S–338S.
  16. Harnack L, Walters S & Jacobs JR (2003) Dietary intake and food sources of whole grains among US children and adolescents: data from the 1994–1996 continuing survey of food intakes by individuals. Journal of the American Dietetic Association 103, 1015–1019.

MK/R