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Jenkins DJA, Jones PJ, Frohlich J, Lamarche B, Ireland C, Nishi SK, Srichaikul K, Galange P, Pellini C, Faulkner D, de Souza RJ, Sievenpiper JL, Mirrahimi A, Jayalath VH, Augustin LS, Bashyam B, Leiter LA, Josse R, Couture P, Ramprasath V, Kendall CWC. The effect of a dietary portfolio compared to a DASH-type diet on blood pressure. Nutr Metab Cardiovasc Dis 2015; 25:1132-1139. [PMID: 26552742 DOI: 10.1016/j.numecd.2015.08.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 08/07/2015] [Accepted: 08/12/2015] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND AIM Compared to a DASH-type diet, an intensively applied dietary portfolio reduced diastolic blood pressure at 24 weeks as a secondary outcome in a previous study. Due to the importance of strategies to reduce blood pressure, we performed an exploratory analysis pooling data from intensively and routinely applied portfolio treatments from the same study to assess the effect over time on systolic, diastolic and mean arterial pressure (MAP), and the relation to sodium (Na(+)), potassium (K(+)), and portfolio components. METHODS AND RESULTS 241 participants with hyperlipidemia, from four academic centers across Canada were randomized and completed either a DASH-type diet (control n = 82) or a dietary portfolio that included, soy protein, viscous fibers and nuts (n = 159) for 24 weeks. Fasting measures and 7-day food records were obtained at weeks 0, 12 and 24, with 24-h urines at weeks 0 and 24. The dietary portfolio reduced systolic, diastolic and mean arterial blood pressure compared to the control by 2.1 mm Hg (95% CI, 4.2 to -0.1 mm Hg) (p = 0.056), 1.8 mm Hg (CI, 3.2 to 0.4 mm Hg) (p = 0.013) and 1.9 mm Hg (CI, 3.4 to 0.4 mm Hg) (p = 0.015), respectively. Blood pressure reductions were small at 12 weeks and only reached significance at 24 weeks. Nuts, soy and viscous fiber all related negatively to change in mean arterial pressure (ρ = -0.15 to -0.17, p ≤ 0.016) as did urinary potassium (ρ = -0.25, p = 0.001), while the Na(+)/K(+) ratio was positively associated (ρ = 0.20, p = 0.010). CONCLUSIONS Consumption of a cholesterol-lowering dietary portfolio also decreased blood pressure by comparison with a healthy DASH-type diet. CLINICAL TRIAL REG. NO.: NCT00438425, clinicaltrials.gov.
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Affiliation(s)
- D J A Jenkins
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada; Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, ON, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada.
| | - P J Jones
- Richardson Center for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, MB, Canada
| | - J Frohlich
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - B Lamarche
- School of Nutrition, Institute of Nutrition and Functional Foods, Laval University, Quebec City, QC, Canada
| | - C Ireland
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada
| | - S K Nishi
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada
| | - K Srichaikul
- Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada; Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - P Galange
- Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada; Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - C Pellini
- Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada; Faculty of Medicine, University of Ottawa, Ottawa, ON, Canada
| | - D Faulkner
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada
| | - R J de Souza
- Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada; Department of Clinical Epidemiology & Biostatistics, McMaster University, Hamilton, ON, Canada
| | - J L Sievenpiper
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada; Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, ON, Canada
| | - A Mirrahimi
- Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada
| | - V H Jayalath
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada
| | - L S Augustin
- Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada
| | - B Bashyam
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada
| | - L A Leiter
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada; Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, ON, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - R Josse
- Department of Medicine, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Division of Endocrinology and Metabolism, St. Michael's Hospital, Toronto, ON, Canada; Li Ka Shing Knowledge Institute, St. Michael's Hospital, Toronto, ON, Canada
| | - P Couture
- Institute of Nutrition and Functional Foods, Laval University, Quebec City, QC, Canada
| | - V Ramprasath
- Richardson Center for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, MB, Canada
| | - C W C Kendall
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, Toronto, ON, Canada; College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK, Canada
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Rossi M, Turati F, Lagiou P, Trichopoulos D, Augustin LS, La Vecchia C, Trichopoulou A. Mediterranean diet and glycaemic load in relation to incidence of type 2 diabetes: results from the Greek cohort of the population-based European Prospective Investigation into Cancer and Nutrition (EPIC). Diabetologia 2013; 56:2405-13. [PMID: 23975324 DOI: 10.1007/s00125-013-3013-y] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 07/09/2013] [Indexed: 01/12/2023]
Abstract
AIMS/HYPOTHESIS The role of diet in the prevention of diabetes remains uncertain. The aim of this study was to investigate two different dietary aspects, i.e. adherence to the Mediterranean diet and glycaemic load (GL), in relation to diabetes occurrence. METHODS We analysed data from the Greek cohort of the population-based European Prospective Investigation into Cancer and Nutrition (EPIC). From a total of 22,295 participants, actively followed for a median of 11.34 years, 2,330 cases of incident type 2 diabetes were recorded. All participants completed a validated, interviewer-administered semi-quantitative food frequency questionnaire at enrolment. From this information, we calculated a ten point Mediterranean diet score (MDS), reflecting adherence to the traditional Mediterranean diet, as well as the dietary GL. We estimated HRs and the corresponding 95% CIs of diabetes using Cox proportional hazards regression models adjusted for potential confounders. RESULTS A higher MDS was inversely associated with diabetes risk (HR 0.88 [95% CI 0.78, 0.99] for MDS ≥ 6 vs MDS ≤ 3). GL was positively associated with diabetes (HR 1.21 [95% CI 1.05, 1.40] for the highest vs the lowest GL quartile). A significant protection of about 20% was found for a diet with a high MDS and a low GL. CONCLUSIONS/INTERPRETATION A low GL diet that also adequately adheres to the principles of the traditional Mediterranean diet may reduce the incidence of type 2 diabetes.
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Affiliation(s)
- M Rossi
- Department of Epidemiology, IRCCS-Istituto di Ricerche Farmacologiche Mario Negri, via La Masa, 19, 20156, Milan, Italy
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Abstract
BACKGROUND Dietary glycemic index (GI) and glycemic load (GL) have been related to the risk of selected cancers, but the issue remains open. PATIENTS AND METHODS Mailed questionnaires were completed between 1994 and 1997 in eight Canadian provinces for incident, histologically confirmed cases of the stomach (n=1182), colon (n=1727), rectum (n=1447), liver (n=309), pancreas (n=628), lung (n=3341), breast (n=2362), ovary (n=442), prostate (n=1799), testis (n=686), kidney (n=1345), bladder (n=1029), brain (n=1009), non-Hodgkin's lymphomas (NHL, n=1666), leukemias (n=1069), multiple myelomas (n=343), and 5039 population controls. Dietary information on eating habits 2 years before participants' enrollment in the study was obtained using a validated food frequency questionnaire (FFQ). Odds ratios (ORs) and 95% confidence intervals (CI) were derived by unconditional logistic regression including recognized confounding factors. RESULTS Dietary GI was positively associated with the risk of prostate cancer (OR, 1.26 for the highest versus the lowest quartile). A higher dietary GL significantly increased the risk of colorectal (OR, 1.28), rectal (OR, 1.44) and pancreatic (OR, 1.41) cancers. No other significant associations were found. CONCLUSIONS Our findings suggest that a diet high in GI and GL is associated with increased risk of selected cancers.
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Affiliation(s)
- J Hu
- Science Integration Division, Centre for Chronic Disease Prevention and Control, Public Health Agency of Canada, Ottawa, ON, Canada.
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Tavani A, Bosetti C, Negri E, Augustin LS, Jenkins DJA, La Vecchia C. Carbohydrates, dietary glycaemic load and glycaemic index, and risk of acute myocardial infarction. Heart 2003; 89:722-6. [PMID: 12807839 PMCID: PMC1767713 DOI: 10.1136/heart.89.7.722] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/22/2003] [Indexed: 11/04/2022] Open
Abstract
OBJECTIVES To assess the relation between selected carbohydrate foods, dietary glycaemic load and glycaemic index, and the risk of non-fatal acute myocardial infarction in a population with a high intake of refined carbohydrates. DESIGN AND SETTING Hospital based case-control study conducted in Milan, Italy, between 1995 and 1999. PATIENTS 433 non-diabetic subjects with a first episode of non-fatal acute myocardial infarction, and 448 controls admitted to hospital for a wide spectrum of acute conditions unrelated to known or potential risk factors for acute myocardial infarction. METHODS Information was collected by interviewer administered questionnaires. Multivariate odds ratios (OR) and 95% confidence intervals (CI) were obtained by multiple logistic regression models. RESULTS Compared with patients in the lowest tertile of intake, the multivariate OR for those in the highest tertile was 1.00 for bread, 1.27 for pasta and rice, 1.38 for soups, 0.78 for potatoes, 0.97 for desserts, and 1.00 for sugar. The OR for the highest tertile of score was 1.08 for glycaemic load and 1.38 for glycaemic index. None of the estimates was significant. A significant association with acute myocardial infarction risk was found for glycaemic index in patients aged > or = 60 years (OR 1.81, 95% CI 1.07 to 3.07 for the highest tertile of score compared with the lowest) and in those with a body mass index > or = 25 kg/m2 (OR 2.02, 95% CI 1.21 to 3.34). CONCLUSIONS In this Italian population high glycaemic load and glycaemic index were not strongly associated with acute myocardial infarction risk, but slightly increased odds ratios were observed for glycaemic index in elderly people and in association with overweight.
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Affiliation(s)
- A Tavani
- Istituto di Ricerche Farmacologiche Mario Negri, Milan, Italy.
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Abstract
AIM The intent of this review is to critically analyze the scientific evidence on the role of the glycemic index in chronic Western disease and to discuss the utility of the glycemic index in the prevention and management of these disease states. BACKGROUND The glycemic index ranks foods based on their postprandial blood glucose response. Hyperinsulinemia and insulin resistance, as well as their determinants (eg high energy intake, obesity, lack of physical activity) have been implicated in the etiology of diabetes, coronary heart disease and cancer. Recently, among dietary factors, carbohydrates have attracted much attention as a significant culprit, however, different types of carbohydrate produce varying glycemic and insulinemic responses. Low glycemic index foods, characterized by slowly absorbed carbohydrates, have been shown in some studies to produce beneficial effects on glucose control, hyperinsulinemia, insulin resistance, blood lipids and satiety. METHOD Studies on the short and long-term metabolic effects of diets with different glycemic indices will be presented and discussed. The review will focus primarily on clinical and epidemiological data, and will briefly discuss in vitro and animal studies related to possible mechanisms by which the glycemic index may influence chronic disease.
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Affiliation(s)
- L S Augustin
- Servizio di Epidemiologia, Centro di Riferimento Oncologico, Istituto Nazionale Tumori, Aviano, Italy.
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Augustin LS, Dal Maso L, La Vecchia C, Parpinel M, Negri E, Vaccarella S, Kendall CW, Jenkins DJ, Francesch S. Dietary glycemic index and glycemic load, and breast cancer risk: a case-control study. Ann Oncol 2001; 12:1533-8. [PMID: 11822751 DOI: 10.1023/a:1013176129380] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Certain types of carbohydrates increase glucose and insulin levels to a greater extent than others. In turn, insulin may raise levels of insulin-like growth factors, which may influence breast cancer risk. We analyzed the effect of type and amount of carbohydrates on breast cancer risk, using the glycemic index and the glycemic load measures in a large case-control study conducted in Italy. PATIENTS AND METHODS Cases were 2,569 women with incident, histologically-confirmed breast cancer interviewed between 1991 and 1994. Controls were 2588 women admitted to the same hospital network for a variety of acute, non-neoplastic conditions. Average daily glycemic index and glycemic load were calculated from a validated 78-item food frequency questionnaire. RESULTS Direct associations with breast cancer risk emerged for glycemic index (odds ratio, OR for highest vs. lowest quintile = 1.4; P for trend <0.01) and glycemic load (OR = 1.3; P < 0.01). High glycemic index foods, such as white bread, increased the risk of breast cancer (OR = 1.3) while the intake of pasta, a medium glycemic index food, seemed to have no influence (OR = 1.0). Findings were consistent across different strata of menopausal status, alcohol intake, and physical activity level. CONCLUSIONS This study supports the hypothesis of moderate, direct associations between glycemic index or glycemic load and breast cancer risk and, consequently, a possible role of hyperinsulinemia/insulin resistance in breast cancer development.
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Affiliation(s)
- L S Augustin
- Servizio di Epidemiologia, Centro di Riferimento Oncologico, Istituto Nazionale Tumori, Aviano, Italy
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Jenkins DJ, Kendall CW, Vidgen E, Augustin LS, van Erk M, Geelen A, Parker T, Faulkner D, Vuksan V, Josse RG, Leiter LA, Connelly PW. High-protein diets in hyperlipidemia: effect of wheat gluten on serum lipids, uric acid, and renal function. Am J Clin Nutr 2001; 74:57-63. [PMID: 11451718 DOI: 10.1093/ajcn/74.1.57] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND The metabolic effects of diets high in vegetable protein have not been assessed despite much recent interest in the effect of soy proteins in reducing serum cholesterol. OBJECTIVE We assessed the metabolic effects of diets high in vegetable protein (specifically, wheat gluten) on serum lipids, uric acid concentrations, and renal function. DESIGN Twenty hyperlipidemic men and women consumed isoenergetic test (high-protein) and control metabolic diets for 1 mo in a randomized crossover design. In the high-protein diet, 11% of the total dietary energy from starch in the control bread was replaced by vegetable protein (wheat gluten), resulting in 27% of total energy from protein compared with 16% in the control diet. In other respects, the 2 diets were identical. RESULTS Compared with the control, the high-protein diet resulted in lower serum concentrations of triacylglycerol (by 19.2 +/- 5.6%; P = 0.003), uric acid (by 12.7 +/- 2.0%; P < 0.001), and creatinine (by 2.5 +/- 1.1%; P = 0.035) and higher serum concentrations of urea (by 42.2 +/- 5.8%; P < 0.001) and a higher 24-h urinary urea output (by 99.2 +/- 17.2%; P < 0.001). No significant differences were detected in total or HDL cholesterol or in the renal clearance of creatinine. LDL oxidation, assessed as the ratio of conjugated dienes to LDL cholesterol in the LDL fraction, was lower with the high-protein diet (by 10.6 +/- 3.6%; P = 0.009). CONCLUSIONS High intakes of vegetable protein from gluten may have beneficial effects on cardiovascular disease risk by reducing oxidized LDL, serum triacylglycerol, and uric acid. Further studies are required to assess the longer-term effects on renal function.
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Affiliation(s)
- D J Jenkins
- Clinical Nutrition and Risk Factor Modification Center and the Department of Medicine, the Division of Endocrinology and Metabolism, St Michael's Hospital, Toronto, Canada
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Jenkins DJ, Kendall CW, Vidgen E, Vuksan V, Jackson CJ, Augustin LS, Lee B, Garsetti M, Agarwal S, Rao AV, Cagampang GB, Fulgoni V. Effect of soy-based breakfast cereal on blood lipids and oxidized low-density lipoprotein. Metabolism 2000; 49:1496-500. [PMID: 11092518 DOI: 10.1053/meta.2000.17703] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Consumption of soy protein may reduce the risk of cardiovascular disease both through reduction in serum lipids and by the antioxidant properties of protein-associated soy isoflavones. However, the effect that processing required for the manufacture of breakfast cereals may have on the lipid lowering and antioxidant activities of soy has not been studied. We have therefore assessed the health benefits of soy incorporation into breakfast cereals. Twenty-five hyperlipidemic men and women took soy (providing 36 g/d soy protein and 168 mg/d isoflavones) and control breakfast cereals, each for 3 weeks in a randomized crossover study with a 2-week washout period between treatments. Fasting blood samples were obtained pretreatment and at weeks 2 and 3 of each treatment. No significant difference was seen in serum lipids between treatments at week 3 apart from a 3.8% +/- 1.5% higher apolipoprotein A-1 level on control versus soy (P = .021). However, oxidized low-density lipoprotein (LDL) was reduced on the test compared with the control both as total dienes in LDL and as the ratio of conjugated dienes to cholesterol in the LDL fraction by 9.2% +/- 4.3% (P = .042) and 8.7% +/- 4.2% (P = .050), respectively. High isoflavone intakes in soy breakfast cereals may decrease the risk of cardiovascular disease by reducing oxidized LDL, while having no significant effect on the absolute concentration of LDL cholesterol.
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Affiliation(s)
- D J Jenkins
- Department of Nutritional Sciences, St. Michael's Hospital, University of Toronto, Ontario, Canada
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Jenkins DJ, Kendall CW, Vuksan V, Vidgen E, Wong E, Augustin LS, Fulgoni V. Effect of cocoa bran on low-density lipoprotein oxidation and fecal bulking. Arch Intern Med 2000; 160:2374-9. [PMID: 10927737 DOI: 10.1001/archinte.160.15.2374] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Legumes have reported benefits in terms of reduced risk for coronary heart disease and of colonic health. A novel legume fiber, cocoa bran, also may have favorable health effects on serum lipid levels, low-density lipoprotein (LDL) cholesterol oxidation, and fecal bulk. METHODS Twenty-five healthy normolipidemic subjects (13 men and 12 women) (mean +/- SEM age, 37 +/- 2 years; mean +/- SEM body mass index [calculated as weight in kilograms divided by the square of height in meters], 24.6 +/- 0.7) ate cocoa-bran and chocolate-flavored low-fiber breakfast cereals for 2-week periods, with 2-week washout, in a double-blind crossover study. The cocoa-bran cereal provided 25.0 g/d of total dietary fiber (TDF). The low-fiber cereal (5.6 g/d TDF) was of similar appearance and energy value. Fasting blood samples were obtained at the start and end of each period, and 4-day fecal collections were made from days 11 through 14. RESULTS High-density lipoprotein (HDL) cholesterol level was higher (7.6% +/- 2.9%; P =.02) and the LDL/HDL cholesterol ratio was lower (6.7% +/- 2.3%; P =.007) for cocoa-bran compared with low-fiber cereal at 2 weeks. No effect was seen on LDL cholesterol oxidation. Mean fecal output was significantly higher for cocoa-bran than for low-fiber cereal (56 +/- 14 g/d; P<.001) and equal to the increase seen in the same subjects with wheat fiber in a previous study. CONCLUSIONS A chocolate-flavored cocoa-bran cereal increased fecal bulk similarly to wheat bran and was associated with a reduction in the LDL/HDL cholesterol ratio. In view of the low-fat, high-fiber nature of the material, these results suggest a possible role for this novel fiber source in the diets of normal, hyperlipidemic, and constipated subjects.
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Affiliation(s)
- D J Jenkins
- Clinical Nutrition and Risk Factor Modification Center, St Michael's Hospital, Toronto, Ontario, Canada
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Abstract
Several epidemiological studies link consumption of fibre-rich foods to a reduced risk of type 2 diabetes and CHD. The 'fibre hypothesis' suggested that this was a direct effect of fibre. However, fibre-rich foods contain different types of fibre as well as other potentially beneficial compounds, and many foods naturally high in fibre have low glycaemic and insulinaemic indices, possibly due to food form. The question therefore emerges as to the effect of isolated fibre per se on insulin sensitivity, lipids and other risk factors associated with the metabolic syndrome. Many beneficial effects are seen with pharmacological doses of isolated viscous soluble fibre, including improved insulin sensitivity, decreased LDL-cholesterol levels and decreased clotting factors. Similar effects are seen with low glycaemic-index foods. In contrast, insoluble non-viscous cereal fibre is not seen to act directly on risk factors when taken in refined foods such as in milled flour. Since cereal fibre, the major type of fibre in western diets, does not directly act on the risk factors for the metabolic syndrome, the question remains as to possible mechanisms. Until now, fibre and the nature and processing of the starch and particle size have been seen as the main determinants of the metabolic response to starchy foods. However, fibre-rich foods also have an increased protein-to-carbohydrate ratio. Hence we suggest that the protective effect of fibre may also be due to increased vegetable protein content, which may act directly to reduce clotting factors and oxidized LDL-cholesterol levels.
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Affiliation(s)
- D J Jenkins
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada
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Jenkins DJ, Kendall CW, Axelsen M, Augustin LS, Vuksan V. Viscous and nonviscous fibres, nonabsorbable and low glycaemic index carbohydrates, blood lipids and coronary heart disease. Curr Opin Lipidol 2000; 11:49-56. [PMID: 10750694 DOI: 10.1097/00041433-200002000-00008] [Citation(s) in RCA: 237] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Viscous fibres such as guar, glucomannans, pectins, oat betaglucan and psyllium continue to be seen as hypocholesterolaemic. Nevertheless, in large cohort studies, ironically it is the insoluble cereal fibre that has been demonstrated to relate negatively to cardiovascular disease and diabetes, despite an absence of effect on fasting lipids or postprandial glycaemia. In general, resistant or nonabsorbable starch is lipid neutral, whereas some nonabsorbable sugars or oligosaccharides may raise serum cholesterol, possibly through providing more acetate after colonic fermentation by colonic microflora. On the other hand, fructo-oligosaccharides appear to reduce serum triglycerides for reasons that are not entirely clear. Of possibly greater recent interest have been the carbohydrates that are not so much resistant to absorption, but rather are slowly absorbed. They possess some of the features of dietary fibre in providing a substrate for colonic bacterial fermentation. In the small intestine, however, they form lente or sustained release carbohydrate. In the form of low glycaemic index foods, lente carbohydrate consumption has been shown to relate to improved blood lipid profiles in hyperlipidaemic individuals and improved glycaemic control in diabetes. In larger cohort studies, low glycaemic index foods or low glycaemic load diets have been associated with higher HDL-cholesterol levels and reduced incidence of diabetes and cardiovascular disease.
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Affiliation(s)
- D J Jenkins
- Clinical Nutrition & Risk Factor Modification Center, St. Michael's Hospital, and Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada.
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Jenkins DJ, Kendall CW, Vuksan V, Augustin LS, Li YM, Lee B, Mehling CC, Parker T, Faulkner D, Seyler H, Vidgen E, Fulgoni V. The effect of wheat bran particle size on laxation and colonic fermentation. J Am Coll Nutr 1999; 18:339-45. [PMID: 12038477 DOI: 10.1080/07315724.1999.10718873] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
OBJECTIVE Due to perceived inferior fecal bulking ability, finely ground wheat bran is not recommended for treatment of colonic disorders, despite possible short chain fatty acid generation with potential benefits for colonic mucosal health. We therefore tested the effects of very fine particle size wheat bran on colonic function. METHODS Two studies, each with three phases, were undertaken in healthy subjects in a randomized crossover design. In one study (metabolic, n=23) subjects took three diets containing either an additional 19 g/d dietary fiber with mean particle size (MPS) 50 microm or 758 microm in bread or a control low fiber bread. In the other study where the supplement was provided as a breakfast cereal (ad libitum, n=24) the respective wheat bran MPS were 692 microm and 1158 microm and the control was low fiber. Fecal collections were obtained during the last week of each diet. In the metabolic study, fecal short chain fatty acids were measured and 12-hour breath gas collections obtained. RESULTS In both studies, wheat bran supplements significantly increased fecal bulk compared to the control (p<0.004), with no significant differences between brans of different particle size and no differences in fecal water content. However, higher fecal butyrate concentrations (p<0.007), butyrate output and breath CH4 levels (p=0.025) were seen on the low MPS wheat bran compared to the other two treatments, suggesting increased bacterial fermentation. CONCLUSIONS Fine MPS wheat bran is an effective fecal bulking agent and may have added advantages if increased butyrate concentrations promote colonic mucosal integrity.
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Affiliation(s)
- D J Jenkins
- Clinical Nutrition and Risk Factor Modification Center, St. Michael's Hospital, Toronto, Ontario, Canada
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Jenkins DJ, Kendall CW, Vuksan V, Augustin LS, Mehling C, Parker T, Vidgen E, Lee B, Faulkner D, Seyler H, Josse R, Leiter LA, Connelly PW, Fulgoni V. Effect of wheat bran on serum lipids: influence of particle size and wheat protein. J Am Coll Nutr 1999; 18:159-65. [PMID: 10204832 DOI: 10.1080/07315724.1999.10718844] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE Wheat fiber appears to protect from cardiovascular disease despite its lack of consistent effect on serum lipids. We therefore wished to determine whether reported inconsistencies in the effect of wheat bran resulted from differences in particle size or its high gluten content. METHODS Two studies were conducted. In one-month metabolic diets, 24 hyperlipidemic subjects consumed breads providing an additional 19 g/d dietary fiber as medium or ultra-fine wheat bran and extra protein (10% of energy as wheat gluten). In two-week ad libitum diets, 24 predominantly normolipidemic subjects consumed breakfast cereals providing an additional 19 g/d of dietary fiber as coarse or a mixture of ultra-fine and coarse wheat bran with no change in gluten intake. Both studies followed a randomized crossover design with control periods when subjects ate low-fiber breads and cereals respectively with no added gluten. Fasting blood lipids were measured on day zero and at the end of each phase. RESULTS Wheat bran had no effect on total, LDL or HDL cholesterol irrespective of particle size or level of gluten in the diet. However, consumption of increased gluten in the metabolic study was associated with a 13+/-4% reduction in serum triglycerides (p = 0.005) which was not seen in the normal-gluten ad libitum study. CONCLUSIONS The protective effect of wheat fiber in cardiovascular disease cannot be explained by an effect of wheat bran in reducing serum cholesterol although in hyperlipidemic subjects displacement of carbohydrate by gluten on the high-fiber phases was associated with lower serum triglycerides.
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Affiliation(s)
- D J Jenkins
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Ontario, Canada
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Jenkins DJ, Vuksan V, Kendall CW, Würsch P, Jeffcoat R, Waring S, Mehling CC, Vidgen E, Augustin LS, Wong E. Physiological effects of resistant starches on fecal bulk, short chain fatty acids, blood lipids and glycemic index. J Am Coll Nutr 1998; 17:609-16. [PMID: 9853541 DOI: 10.1080/07315724.1998.10718810] [Citation(s) in RCA: 135] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
OBJECTIVE To assess the effects on fecal bulking, fecal short chain fatty acid (SCFA) production, blood lipids and glycemic indices of two different forms of resistant starch (RS2 and RS3) from a high-amylose cornstarch. METHODS Twenty-four healthy subjects (12 men; 12 women) consumed four supplements taken for 2 weeks in random order separated by 2-week washout periods. The supplements were a low-fiber (control) and supplements providing an additional 30 g dietary fiber as wheat bran (high-fiber control) or the equivalent amount of resistant starch analyzed gravimetrically as dietary fiber from RS2 or RS3. Four-day fecal collections and 12-hour breath gas collections were obtained at the end of each period. Fasting blood was taken at the beginning and end of each period. Glycemic indices of supplements were also assessed. RESULTS The wheat bran supplement increased fecal bulk 96+/-14 g/day compared with the low-fiber control (p<0.001) with the mean for both resistant starches also being greater (22+/-8 g/day) than the low-fiber control (p=0.013). On the resistant starch phases, the mean fecal butyrate:SCFA ratio, which has been suggested to have positive implications for colonic health, was significantly above the low-fiber control by 31+/-14% (p=0.035). Resistant starches did not alter serum lipids, urea or breath H2 or CH4. No significant differences in glycemic index were seen between the RS and control supplements. CONCLUSION The potential physiological benefits of the resistant starches studied appear to relate to colonic health in terms of effects on fecal bulk and SCFA metabolism.
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Affiliation(s)
- D J Jenkins
- Department of Nutritional Sciences, Faculty of Medicine, University of Toronto and the Clinical Nutrition and Risk Factor Modification Center, St Michael's Hospital, Ontario, Canada
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