Whole Grain vs. Refined Grain
Learn the difference between whole grains and refined grains.
Reduces mortality risk
In both developed and developing countries, cardiovascular diseases (CVD) and cancer are major causes of mortality. A recent meta-analysis (meta-analysis provide the highest level of evidence) showed that a greater intake of both-total whole grains and specific whole-grain foods, was significantly associated with a lower risk of all-cause mortality, mortality from cardiovascular disease and risk of mortality from total cancers. An increase of 3 servings total whole grains was associated with a 17% lower risk of mortality from all causes, a 25% lower risk of mortality from CVD, and a 10% reduced risk of total-cancer mortality.1
A study among a large US population (367,442 participants) followed through a period of 14 years, found that increased consumption of whole grains or cereal fibre was significantly associated with reduce risk of all-cause mortality and death from CVD, cancer, diabetes, respiratory disease, infections, and other causes. As compared with individuals with the lowest intake of whole grains, those with the highest intake had a 17% lower risk of all-cause mortality and 11 to 48% lower risk of disease-specific mortality. The study specifically examined the association of the whole grain component, namely dietary fibre intake on mortality. As compared with individuals with the lowest intake of cereal fibre, those in the highest intake group had a 19% lower risk of all-cause mortality and 15 to 34% lower risk of disease-specific mortality. The results suggested that the protective effects of whole grains may be due, at least in the main part, to its cereal fibre component.2
Wu H. et al (2015) in a study conducted with 2 large cohorts of US men and women suggested that higher whole grain consumption, with or without added bran or germ, can lower total and CVD mortality. In addition, the bran portion of the whole grain foods, as well as bran added to foods, was significantly associated with a lower CVD mortality. These findings were consistent with previous studies, Nurses’ Health Study (NHS) and Health Professionals Follow-Up study (HPFS) which also suggested that the bran component, but not germ, was significantly associated with reduced risk of diabetes, hypertension, Coronary Heart Disease (CHD) or CVD mortality among those with diabetes, after mutual adjustments of bran and germ.
Reduces CVD risk
It was seen that consumption of whole grain diets lowers LDL cholesterol and total cholesterol in apparently healthy adults when compared to non-whole grain control diets. The effect varied with the type of whole grain consumed and was augmented by simultaneous calorie restriction.4 Earlier studies have shown that the use of statins was associated with healthier lipoprotein profiles when combined with higher whole grain intake (>16g) relative to lower whole grain intake.5
A 6 week intervention trial on healthy adults who were low whole grain consumers (not more than 1 serving of whole grain or whole grain products/day) showed that the consumption of whole grain products resulted in a significant reduction in total, LDL and non-HDL cholesterol.6 The lipid lowering effect in this study appeared to be due to the fibre content of the whole grain rather than due to beta glucan, an established cholesterol lowering agent found in oats.
Reduces risk for type 2 diabetes
A recent review of studies on the effect of whole grain consumption on metabolic parameters showed that the consumption of whole grain foods is able to improve acutely the postprandial glucose and insulin homeostasis compared to similar refined foods in healthy subjects.8
Chanson-Rolle et al report on an inverse relationship between whole grain consumption and the occurrence of type 2 diabetes up to an intake of whole grain ingredients of approximately 50 g/d.
Their model of data analysis suggests an overall absolute reduction of 0.3% in risk of type 2 diabetes for each 10g of whole grain consumed daily.9
Several plausible explanations have been put forth for the whole grain’s mechanism of action in potentially reducing the incidence of type 2 diabetes.
Reduces risk for cancer
Reduces risk for obesity
Whole grains and gut health
The fibre from whole grains such as wheat is mostly insoluble and is known to increase tool bulk, reduce transit time, and make fecal elimination easier and quicker. In this way, consumption of insoluble fibre rich whole grains can regulate bowel functions to promote the wellbeing of healthy people and can function as a remedy to alleviate several gastrointestinal diseases such as peptic ulcers and cancer.16
Whole grains also contain several microbiota accessible substrates such as resistant starch and non-starch polysaccharides such as β-glucan and arabinoxylans, that resist digestion in the upper gastrointestinal tract, making them an important fuel for the gut microbiota. Microbial metabolites such as SCFAs, phenolic metabolites and secondary bile acids play a key role in the intersection between diet and metabolic health by regulating appetite, energy homeostasis, lipid and glucose metabolism, inflammatory status, oxidant stress and activation of the immune system.17
Whole grains and fibre-related but not synonymous
Historically increasing whole grain intake was recommended because they make an important contribution to dietary fibre intake. However, it is important to note that whole grain does not always equate with high fibre19 and the focus in dietary guidance on increasing whole grains intake has not improved levels of fibre consumption.14 This is because different whole grains, such as wheat, barley, brown rice, and corn, vary widely in their fibre content.
Recommendations for fibre and whole grains
Wheat bran: the best fibre for promotion regularity
Wheat bran is a very rich source of insoluble fibre (arabinoxylans, cellulose and beta glucans) along with vitamins, minerals and antioxidants. It regulates gastro intestinal physiology and health by delaying gastric emptying and increasing fecal bulk. The effect of wheat bran on increasing fecel bulk is greater than other grains such as oats or vegetables and fruits.25 Wheat bran is considered as the “gold standard” when it comes to fecal bulking and promoting regularity since no other fibre or laxative has been shown to be as effective.26
Consumption of wheat bran has protective effect against diseases such as cardiovascular, obesity, and gastrointestinal disorders such as constipation, diverticulosis and colorectal cancer.25
European Food Safety Authority (EFSA) has an approved health claim on wheat bran which states – “Wheat bran fibre contributes to an increase in faecal bulk and reduction in intestinal transit time”.27
1 Benisi-Kohansal S. etal (2016) Whole-Grain Intake and Mortality from All Causes, Cardiovascular Disease, and Cancer: A Systematic Review and Dose-Response Meta-Analysis of Prospective Cohort Studies. Adv Nutr. Nov; 7(6):1052-1065.
2 Huang Tao etal (2015) Consumption of whole grains and cereal fibre and total and cause-specific mortality: prospective analysis of 367,442 individuals. BMC Medicine (2015) 13:59.
3 Wu H.etal (2015) Association Between Dietary WholeGrain In take and Risk of Mortality Two Large Prospective Studies in US Men and Women. JAMA Intern Med. 2015;175(3):373-384.
4 Hollander Pernille LB etal (2015) Whole-grain and blood lipid changes in apparently healthy adults: a systematic review and meta-analysis of randomized controlled studies. Am J Clin Nutr 2015;102:556-72.
5 Wang H (2014) Association between statin use and serum cholesterol concentrations is modified by whole-grain consumption: NHANES 2003-2006. Am J Clin Nutr 2014;100:1149-57.
6 Cooper D.N. (2017) The Effects of Moderate Whole Grain Consumption on Fasting Glucose and Lipids, Gastrointestinal Symptoms, and Microbiota. Nutrients 2017,9,173.
7 Kirwan J.P. (2016) A Whole-Grain Diet Reduced Cardiovascular Risk Factors in Overweight and Obese Adults: A Randomized Controlled Trial. J Nutri 2016;146:2244-51.
8 Marventano S. (2017) Whole Grain Intake and Glycaemic Control in Healthy Subjects: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. Nutrients 2017,9,769
9 Chanson-Rolle A. etal (2015) Systematic Review and Meta-Analysis of Human Studies to Support a Quantitative Recommendation for Whole Grain Intake in Relation to Type 2 Diabetes. PLoSONE10(6):e0131377. Doi:10.1371/journal.pone.0131377
10Marc P. McRae (2016) Health Benefits of Dietary Whole Grains: An Umbrella Review of Meta-analyses. Journal of Chiropractic medicine Vol16(no.1)p10-18.
11 Makarem N (2016) Consumption of whole grains and cereal fibre in relation to cancer risk: a systematic review of longitudinal studies. Nutrition Reviews V R Vol.74(6):353-373.
12 Mourouti N (2015) Dietary patterns and breast cancer: a case-control study in women. European Journal of Nutrition, Volume 54, Issue 4, pp 609-617.
13 Knudsen MD (2014) Self-reported whole-grain intake and plasma alkylresorcinol concentrations in combination in relation to the incidence of colorectal cancer. Am J Epidemiol. 2014 May 25;179(10):1188-96
14 Karl J.P. (2017) Substituting whole grains for refined grains in a 6-wk randomized trial favourably affects energy-balance metrics in healthy men and post menopausal women. Am J Clin Nutr 2017;105:589-99.
15 Seal C.J. etal (2016) Whole-grain dietary recommendations: the need for a unified global approach. British Journal of Nutrition. 115,2031-203.
16 Vanegas S.M. etal (2017) Substituting whole grains for refined grains in a 6-wk randomized trials has a modest effect on gut microbiota and immune and inflammatory markets of healthy adults. Am J Clin Nutr 105:635-50.
17 Gong et al (2017 Whole cereal grains and potential health effects: involvement of the gut microbiota. Food Research International 103,84-102.
18 Lawson C.L. etal (2013) Short Term (14 Days) Consumption of Insoluble Wheat Bran Fibre-Containing Breakfast Cereals Improves Subjective Digestive Feelings, General Wellbeing and Bowel Function in a Dose Dependent Manner. Nutrients 2013,5,1436-1455.
19 Ferruzzi M.G. etal (2014) Developing a Standard Definition of Whole-Grain Foods for Dietary Recommendations: Summary Report of a Multi disciplinary Expert Roundtable Discussion. Adv. Ntr. 5:164-176.
20 Mozaffarian R.S. (2013) Identifying whole grain foods: a comparison of different approaches for selecting more healthful whole grain products. Public Health Nutrition: 16(12),2255-2264.
21 USDA 2015-2020 Dietary guidelines for Americans.
22 Seal C.J. etal (2016) Whole-grain dietary recommendations: the need for a unified global approach. British Journal of Nutrition (2016), 115,2031-2038.
23 National Institute for Nutrition (2011) Dietary guidelines for Indians.
24 ICMR Nutrient requirements and recommended dietary allowance for Indians.
25 Baltasar Ruiz-Roso Calvo de Mora. (2015) POSITIVE EFFECTS OF WHEAT BRAN FOR DIGESTIVE HEALTH; SCIENTIFIC EVIDENCE. Nutr Hosp, 32(Supl. 1):41-45.
26 Joanne Slavin (2013) Fibre and Prebiotics: Mechanisms and Health Benefits. Nutrients 2013,5,1417-1435
27 Stevenson L. (2012) Wheat bran: its composition and benefits to health, a European perspective. International Journal of Food Sciences and Nutrition, December, 63(8):1001-1013
Learn the difference between whole grains and refined grains.
Nutritional benefits of grains.
Kellogg’s create a variety of cereals from simple grains, handful of ingredients and some essential nutrients like fibre, vitamins and minerals.