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Why whole grains are protective: biological mechanisms

Published online by Cambridge University Press:  05 March 2007

Joanne Slavin*
Affiliation:
Department of Food Science and Nutrition, University of Minnesota, 1334 Eckles Avenue, St Paul, MN 55108, USA
*
Corresponding author: Dr Joanne Slavin, fax +1 612 625 5272, jslavin@umn.edu
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Abstract

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Epidemiological studies find that whole-grain intake is protective against cancer, cardiovascular disease, diabetes and obesity. Potential mechanisms for this protection are diverse since whole grains are rich in nutrients and phytochemicals. First, whole grains are concentrated sources of dietary fibre, resistant starch and oligosaccharides, carbohydrates that escape digestion in the small intestine and are fermented in the gut, producing short-chain fatty acids (SCFA). SCFA lower colonic pH, serve as an energy source for the colonocytes and may alter blood lipids. These improvements in the gut environment may provide immune protection beyond the gut. Second, whole grains are rich in antioxidants, including trace minerals and phenolic compounds, and these compounds have been linked to disease prevention. Additionally, whole grains mediate insulin and glucose responses. Although lower glycaemic load and glycaemic index have been linked to diabetes and obesity, risk of cancers such as colon and breast cancer have also been linked to high intake of readily-available carbohydrate. Finally, whole grains contain many other compounds that may protect against chronic disease. These compunds include phytate, phyto-oestrogens such as lignan, plant stanols and sterols, and vitamins and minerals. As a consequence of the traditional models of conducting nutrition studies on isolated nutrients, few studies exist on the biological effects of increased whole-grain intake. The few whole-grain feeding studies that are available show improvements in biomarkers with whole-grain consumption, such as weight loss, blood lipid improvement and antioxidant protection.

Type
Session: Health effects of whole grains
Copyright
Copyright © The Nutrition Society 2003

References

Adlercreutz, H, Fotsis, T, Bannwart, C, Hamalainen, E, Bloigu, A, Ollus, A (1986) Urinary estrogen profile determination in young Finnish vegetarian and omnivorous women. Journal of Steroid Biochemistry 24, 289296.CrossRefGoogle ScholarPubMed
Adlercreutz, H, Mazur, W (1997) Phyto-oestrogens and western diseases. Annals of Medicine 29, 95120.CrossRefGoogle ScholarPubMed
Bjorck, I, Granfeldt, Y, Lilijeberg, H, Tovar, J, Asp, N (1994) Food properties affecting the digestion and absorption of carbohydrates. American Journal of Clinical Nutrition 59 688S – 705SCrossRefGoogle ScholarPubMed
Borriello, SP, Setchell, KD, Axelson, M, Lawson, AM (1985) Production and metabolism of lignans by the human faecal flora. Journal of Applied Bacteriology 58, 3743.CrossRefGoogle ScholarPubMed
Gerhardt, AL, Gallo, NB (1998) Full-fat rice bran and oat bran similarly reduce hypercholesterolemia in humans. Journal of Nutrition 128, 865869.CrossRefGoogle ScholarPubMed
Gibson, GR, Beatty, ER, Wang, X, Cummings, JH (1995) Selective stimulation of bifidobacteria in the human colon by oligofructose and inulin. Gastroenterology 108, 975982.CrossRefGoogle ScholarPubMed
Giovannucci, E (1995) Insulin and colon cancer. Cancer Causes & and Control 6, 164179.CrossRefGoogle ScholarPubMed
Granfeldt, Y, Hagander, B, Bjorck, I (1995) Metabolic responses to starch in oat and wheat products. On the importance of food structure, incomplete gelatinization or presence of viscous dietary fibre. European Journal of Clinical Nutrition 49, 189199.Google ScholarPubMed
Hallikainen, MA, Sarkkinen, ES, Uusitupa, MIJ (2000) Plant stanols esters affect serum cholesterol concentrations of hypercholesterolemic men and women in a dose-dependent manner. Journal of Nutrition 130, 767776.CrossRefGoogle ScholarPubMed
Heaton, KW, Marcus, SN, Emmett, PM, Bolton, CH (1988) Particle size of wheat, maize, and oat test meals: effects on plasma glucose and insulin responses and on the rate of starch digestion in vitro. American Journal of Clinical Nutrition 47, 675682.CrossRefGoogle ScholarPubMed
Hu, FB, Manson, JE, Liu, S, Hunter, D, Colditz, GA, Michels, KB, Speizer, FE, Giovannucci, E (1999) Prospective study of adult onset diabetes mellitus (type 2) and risk of colorectal cancer in women. Journal of the National Cancer Inst Institute 91, 542547.CrossRefGoogle ScholarPubMed
Jang, Y, Lee, JH, Kim, OY, Park, HY, Lee, SY (2001) Consumption of whole grain and legume powder reduces insulin demand, lipid peroxidation, and plasma homocysteine concentrations in patients with coronary artery disease: randomized controlled clinical trial. Arteriosclerosis Thrombosis and Vascular Biology 21, 20652071.CrossRefGoogle ScholarPubMed
Jarvi, A, Karlstrom, B, Granfeldt, YE, Bjorck, I, Vessby, B (1995) The influence of food structure on postprandial metabolism in patients with non-insulin-dependent diabetes mellitus. American Journal of Clinical Nutrition 61, 837842.CrossRefGoogle ScholarPubMed
Jenkins, DJ, Wesson, V, Wolever, TM, Jenkins, AL, Kalmusky, J, Guidici, S, Csima, A, Josse, RG, Wong, GS (1988) Wholemeal versus wholegrain breads: proportion of whole or cracked grain and the glycaemic response. British Medical Journal 297, 958960.CrossRefGoogle ScholarPubMed
Jenkins, DJA, Wolever, TMS, Jenkins, AL, Giordano, C, Giudici, S, Thompson, LU, Kalmusky, J, Josse, RG, Wong, GS (1986) Low glycemic response to traditionally processed wheat and rye products: bulgur and pumpernickel bread. American Journal of Clinical Nutrition 43, 516520.CrossRefGoogle ScholarPubMed
Juntunen, KS, Niskanen, LK, Liukkonen, KH, Poutanen, KS, Holst, JJ, Hykkanen, HM (2002) Postprandial glucose, insulin, and incretin responses to grain products in healthy subjects. American Journal of Clinical Nutrition 75, 254262.CrossRefGoogle ScholarPubMed
Katz, DL, Nawaz, H, Boukhalil, J, Chan, W, Ahmadi, R, Giannamore, V, Sarrel, PM (2001) Effects of oat and wheat cereals on endothelial responses. Preventative Medicine 33, 476484.CrossRefGoogle ScholarPubMed
Kilkkinen, A, Stumpf, K, Pietinen, P, Valsta, LM, Tapanainen, H, Adlercreutz, H (2001) Determinants of serum enterolactone concentration. American Journal of Clinical Nutrition 73, 10941100.CrossRefGoogle ScholarPubMed
Kroon, PA, Faulds, CB, Ryden, P, Robertson, JA, Williamson, G (1997) Release of covalently bound ferulic acid from fiber in the human colon. Journal of Agricultural and Food Chemistry 45, 661667.CrossRefGoogle Scholar
McIntyre, A, Vincent, RM, Perkins, AC, Spiller, RC (1997) Effect of bran, ispaghula, and inert plastic particles on gastric emptying and small bowel transit in humans: the role of physical factors. Gut 40, 223227.CrossRefGoogle ScholarPubMed
McPherson, R, Spiller, GA (1995) Effects of dietary fatty acids and cholesterol on cardiovascular disease risk factors in man.In Handbook of Lipids in Human Nutrition 4149 [Spiller, GA, editor]. Boca Raton, FL: CRC Press.Google Scholar
Marlett, JA, McBurney, MI, Slavin, JL (2002) Position of the American Dietetic Association: Health implications of dietary fiber. Journal of the American Dietetic Association 102, 9931000.CrossRefGoogle ScholarPubMed
Miller, G (2001) Whole grain, fiber and antioxidants.In CRC Handbook of Dietary Fiber in Human Nutrition 453460 [Spiller, GA, editor]. Boca Raton, FL: CRC Press.CrossRefGoogle Scholar
Nair, PP, Turjmann, N, Kessic, G, Calkins, B, Goodman, GT, Davidovitz, H, Nimmagadda, G (1984) Diet, nutrition intake and metabolism in populations at high and low risk for colon cancer. American Journal of Clinical Nutrition 40, 927930.CrossRefGoogle ScholarPubMed
Pereira, MA, Jacobs, DJ, Pins, JJ, Raatz, SK, Gross, MD, Slavin, JL, Seaquist, ER (2002) Effect of whole grains on insulin sensitivity in overweight hyperinsulinemic adults. American Journal of Clinical Nutrition 75, 848855.CrossRefGoogle ScholarPubMed
Pereira, MA, Pins, JJ, Jacobs, DR, Marquart, L, Keenan, JM (2001) Whole grains, cereal fiber and chronic diseases: Epidemiologic evidence.In CRC Handbook of Dietary Fiber in Human Nutrition 461479 [Spiller, GA, editor]. Boca Raton, FL: CRC Press.Google Scholar
Pins, JJ, Geleva, D, Leemam, K, Fraze, 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, 353359.Google ScholarPubMed
Schoen, RE, Tangen, CM, Kuller, LH, Burke, GL, Cushman, M, Tracy, RP, Dobs, A, Savage, PJ (1999) Increased blood glucose and insulin, body size and incident colorectal cancer. Journal of the National Cancer Institute 91, 11471154.CrossRefGoogle ScholarPubMed
Slavin, JL, Jacobs, D, Marquart, L (2001a) Grain processing and nutrition. Critical Reviews in Biotechnology 21, 4966.CrossRefGoogle ScholarPubMed
Slavin, JL, Jacobs, D, Marquart, L, Wiemer, K (2001b) The role of whole grains in disease prevention. Journal of the American Dietetic Association 101, 780785.CrossRefGoogle ScholarPubMed
Slavin, JL, Martini, MC, Jacobs, DR, Marquart, L (1999) Plausible mechanisms for the protectiveness of whole grains. American Journal of Clinical Nutrition 70 459S – 463SCrossRefGoogle ScholarPubMed
Thompson, LU, Seidl, MM, Rickard, SE, Orcheson, LJ, Fong, HH (1996) Antitumorigenic effect of a mammalian lignan precursor from flaxseed. Nutrition and Cancer 26, 159165.CrossRefGoogle ScholarPubMed
Truswell, AS (2002) Cereal grains and coronary heart disease. European Journal of Clinical Nutrition 56, 114.CrossRefGoogle ScholarPubMed
Van Dam, RM, Rimm, EB, Willett, WC, Stampfer, MJ, Hu, FB (2002) Dietary patterns and risk for type 2 diabetes mellitus in US men. Annals of Internal Medicine 136, 201209.CrossRefGoogle ScholarPubMed
Van Loo, J, Coussement, P, De Leenheer, L, Hoebregs, H, Smits, G (1995) On the presence of inulin and oligofructose as natural ingredients in the western diet. Critical Reviews in Food Science and Nutrition 35, 525552.CrossRefGoogle ScholarPubMed
Wrick, K, Robertson, JB, Van Soest, PJ (1983) The influence of dietary fiber source on human intestinal transit and stool output. Journal of Nutrition 113, 14641479.CrossRefGoogle ScholarPubMed
Yankah, VV, Jones, PJH (2001) Phytosterols and health implications – efficacy and nutritional aspects. Inform 12, 899903.Google Scholar