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Exercise and Prebiotic Fiber Provide Gut Microbiota-Driven Benefit in a Survivor to Germ-Free Mouse Translational Model of Breast Cancer. Cancers (Basel) 2022; 14:cancers14112722. [PMID: 35681702 PMCID: PMC9179252 DOI: 10.3390/cancers14112722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/16/2022] [Accepted: 05/24/2022] [Indexed: 11/23/2022] Open
Abstract
Simple Summary Breast cancer is the most common cancer in women worldwide. In recent years, the community of microbes that inhabit the intestinal tract, called the gut microbiota, has been shown to influence patient response to several cancer therapies. On the other hand, treatments such as chemotherapy can disrupt the resident gut microbiota and potentially contribute to poor health outcomes. Strategies to improve the composition of the gut microbiota include dietary and exercise interventions. While diet and exercise are already established as important for breast cancer prevention, during treatment, and for reducing recurrence, little is known about the impact of these factors on the gut microbiota in the context of breast cancer. Therefore, our aim was to examine the impact of exercise and diet on the gut microbiota in breast cancer. Our findings indicate that exercise and prebiotic fiber supplementation may provide benefits to individuals with breast cancer through advantageous gut microbial changes. Our findings of a potential adjuvant of exercise and prebiotics should inspire further mechanistic and clinical investigations. Abstract The gut microbiota plays a role in shaping overall host health and response to several cancer treatments. Factors, such as diet, exercise, and chemotherapy, can alter the gut microbiota. In the present study, the Alberta Cancer Exercise (ACE) program was investigated as a strategy to favorably modify the gut microbiota of breast cancer survivors who had received chemotherapy. Subsequently, the ability of post-exercise gut microbiota, alone or with prebiotic fiber supplementation, to influence breast cancer outcomes was interrogated using fecal microbiota transplant (FMT) in germ-free mice. While cancer survivors experienced little gut microbial change following ACE, in the mice, tumor volume trended consistently lower over time in mice colonized with post-exercise compared to pre-exercise microbiota with significant differences on days 16 and 22. Beta diversity analysis revealed that EO771 breast tumor cell injection and Paclitaxel chemotherapy altered the gut microbial communities in mice. Enrichment of potentially protective microbes was found in post-exercise microbiota groups. Tumors of mice colonized with post-exercise microbiota exhibited more favorable cytokine profiles, including decreased vascular endothelial growth factor (VEGF) levels. Beneficial microbial and molecular outcomes were augmented with prebiotic supplementation. Exercise and prebiotic fiber demonstrated adjuvant action, potentially via an enhanced anti-tumor immune response modulated by advantageous gut microbial shifts.
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Wu N, Mah C, Koentgen S, Zhang L, Grimm MC, El-Omar E, Hold GL. Inflammatory bowel disease and the gut microbiota. Proc Nutr Soc 2021; 80:1-11. [PMID: 34165053 DOI: 10.1017/s002966512100197x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Inflammatory bowel disease (IBD) is a group of immune-mediated disorders characterised by a chronic, relapsing-remitting inflammation predominantly affecting the gastrointestinal tract. IBD is incurable, affecting people in their most productive years. IBD is historically seen as a disease of Westernised nations although in recent times other countries have seen an exponential rise in cases. Although the exact pathogenesis remains unclear, evidence suggests that microbiota changes play a critical role in IBD pathogenesis. Over the past two decades, IBD has become one of the most studied human conditions linked to the gut microbiota. However, deciphering the intricate link between the gut microbiota and therapeutic efficacy remains elusive. This review will summarise the current evidence relating to the gut microbiota and its involvement in IBD pathogenesis as well as the impact of IBD treatments including pharmaceutical-, nutraceutical- and microbial-focused regimens on the gut microbiota.
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Affiliation(s)
- Nan Wu
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Cassandra Mah
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Sabrina Koentgen
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Leo Zhang
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Michael C Grimm
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Emad El-Omar
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, Sydney, New South Wales, Australia
| | - Georgina L Hold
- Microbiome Research Centre, St George and Sutherland Clinical School, University of New South Wales, Sydney, New South Wales, Australia
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Fortuna R, Hart DA, Sharkey KA, Schachar RA, Johnston K, Reimer RA. Effect of a prebiotic supplement on knee joint function, gut microbiota, and inflammation in adults with co-morbid obesity and knee osteoarthritis: study protocol for a randomized controlled trial. Trials 2021; 22:255. [PMID: 33827639 PMCID: PMC8025512 DOI: 10.1186/s13063-021-05212-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 03/20/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Osteoarthritis (OA) is a chronic and painful condition where the articular cartilage surfaces progressively degenerate, resulting in loss of function and progressive disability. Obesity is a primary risk factor for the development and progression of knee OA, defined as the "metabolic OA" phenotype. Metabolic OA is associated with increased fat deposits that release inflammatory cytokines/adipokines, thereby resulting in systemic inflammation which can contribute to cartilage degeneration. There is currently no cure for OA. Prebiotics are a type of dietary fiber that can positively influence gut microbiota thereby reducing systemic inflammation and offering protection of joint integrity in rodents. However, no human clinical trials have tested the effects of prebiotics in adults with obesity suffering from knee OA. Therefore, the purpose of this double-blind, placebo-controlled, randomized trial is to determine if prebiotic supplementation can, through positive changes in the gut microbiota, improve knee function and physical performance in adults with obesity and knee OA. METHODS Adults (n = 60) with co-morbid obesity (BMI > 30 kg/m2) and knee OA (Kellgren-Lawrence grade II-III) will be recruited from the Alberta Hip and Knee Clinic and the Rocky Mountain Health Clinic and surrounding community of Calgary, Canada, and randomized (stratified by sex, BMI, and age) to prebiotic (oligofructose-enriched inulin; 16 g/day) or a calorie-matched placebo (maltodextrin) for 6 months. Anthropometrics, performance-based tests, knee pain, serum inflammatory markers and metabolomics, quality of life, and gut microbiota will be assessed at baseline, 3 months, 6 months (end of prebiotic supplementation), and 3 months following the end of the prebiotic supplementation. CLINICAL SIGNIFICANCE There is growing pressure on health care systems for aggressive OA treatment such as total joint replacement. Less aggressive, yet effective, conservative treatment options have the potential to address the growing prevalence of co-morbid obesity and knee OA by delaying the need for joint replacement or ideally preventing its need altogether. The results of this clinical trial will provide the first evidence regarding the efficacy of prebiotic supplementation on knee joint function and pain in adults with obesity and knee OA. If successful, the results may provide a simple, safe, and easy to adhere to intervention to reduce knee joint pain and improve the quality of life of adults with co-morbid knee OA and obesity. TRIAL REGISTRATION Clinical Trials.gov NCT04172688 . Registered on 21 November 2019.
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Affiliation(s)
- Rafael Fortuna
- Human Performance Laboratory, Faculty of Kinesiology, University of Calgary, Calgary, Alberta Canada
| | - David A. Hart
- McCaig Institute for Bone and Joint Health, Department of Surgery, and Faculty of Kinesiology, University of Calgary, Calgary, Alberta Canada
| | - Keith A. Sharkey
- Hotchkiss Brain Institute and Snyder Institute for Chronic Diseases, Department of Physiology and Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta Canada
| | | | - Kelly Johnston
- Division of Hip and Knee Reconstruction, Department of Surgery, Cumming School of Medicine, University of Calgary, Calgary, Alberta Canada
| | - Raylene A. Reimer
- Faculty of Kinesiology and Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, 2500 University Dr. NW, Calgary, Alberta Canada
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Yang H, Yang L, Zhang J, Li H, Tu Z, Wang X. Exploring functional core bacteria in fermentation of a traditional Chinese food, Aspergillus-type douchi. PLoS One 2019; 14:e0226965. [PMID: 31887171 PMCID: PMC6936781 DOI: 10.1371/journal.pone.0226965] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 12/09/2019] [Indexed: 12/03/2022] Open
Abstract
Douchi is a type of traditional Chinese flavoring food that has been used for thousands of years and is produced by multispecies solid-state fermentation. However, the correlation between the flavor, the microbiota, and the functional core microbiota in Aspergillus-type douchi fermentation remains unclear. In this study, Illumina MiSeq sequencing and chromatography were used to investigate the bacterial community and flavor components in Aspergillus-type douchi fermentation. The dominant phyla were Firmicutes, Proteobacteria, and Actinobacteria, and the dominant genera were Weissella, Bacillus, Anaerosalibacter, Lactobacillus, Staphylococcus, and Enterococcus. A total of 58 flavor components were detected during fermentation, including two alcohols, 14 esters, five pyrazines, three alkanes, four aldehydes, three phenols, six acids, and five other compounds. Bidirectional orthogonal partial least square modeling showed that Corynebacterium_1, Lactococcus, Atopostipes, Peptostreptococcus, norank_o__AKYG1722, Truepera, Gulosibacter, norank_f__Actinomycetaceae, and unclassified_f__Rhodobacteraceae are the functional core microbiota responsible for the formation of the flavor components during douchi fermentation. This is the first study to investigate the functional core microbiota in douchi fermentation using Illumina MiSeq sequencing and chromatographic techniques. Our findings extend our understanding of the relationships between flavor, the microbiota, and the functional core microbiota during Aspergillus-type douchi fermentation.
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Affiliation(s)
- Huilin Yang
- Key Lab of Protection and Utilization of Subtropic Plant Resources of Jiangxi Province, Jiangxi Normal University, Nanchang, China
| | - Lin Yang
- Key Lab of Protection and Utilization of Subtropic Plant Resources of Jiangxi Province, Jiangxi Normal University, Nanchang, China
| | - Ju Zhang
- Key Lab of Protection and Utilization of Subtropic Plant Resources of Jiangxi Province, Jiangxi Normal University, Nanchang, China
| | - Hao Li
- Key Lab of Protection and Utilization of Subtropic Plant Resources of Jiangxi Province, Jiangxi Normal University, Nanchang, China
| | - Zongcai Tu
- Key Lab of Protection and Utilization of Subtropic Plant Resources of Jiangxi Province, Jiangxi Normal University, Nanchang, China
| | - Xiaolan Wang
- Key Lab of Protection and Utilization of Subtropic Plant Resources of Jiangxi Province, Jiangxi Normal University, Nanchang, China
- * E-mail:
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Sahebkar-Khorasani M, Jarahi L, Cramer H, Safarian M, Naghedi-Baghdar H, Salari R, Behravanrad P, Azizi H. Herbal medicines for suppressing appetite: A systematic review of randomized clinical trials. Complement Ther Med 2019; 44:242-252. [PMID: 31126562 DOI: 10.1016/j.ctim.2019.04.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2019] [Revised: 04/13/2019] [Accepted: 04/23/2019] [Indexed: 01/04/2023] Open
Abstract
The suppression of appetite with herbal medicines has become very popular in recent years. We conducted this systematic review to evaluate the recent scientific evidence regarding herbal medicines that are used to suppress appetite. We retrieved clinical trials from PubMed, Cochrane Central Register of Controlled Trials, Web of Science, Scientific Information Database, and IranMedex from January 1, 2013 to April 24, 2018. English and Persian language randomized clinical trials that used herbal medicines to suppress appetite in healthy or obese or overweight individuals were included. Risk of bias was assessed using Cochrane methodology. Out of 591 articles, 22 trials with 973 participants were included. One study on the Meratrim formulation which contained the Sphaeranthus indicus flower heads extract and Garcinia mangostana fruit, revealed longer-term evidence; while 6 studies on Ilex paraguariensis, Spinacia oleracea, Phaseolus vulgaris, Secale cereale, Sorghum bicolor and Plantago showed short-term evidence for suppressing appetite. No serious adverse events were reported. Despite some methodological concerns in the included studies, there is promising evidence for suppressing appetite with herbal medicines that needs to be confirmed in long-term clinical trials with adequate sample size and higher methodological quality with more attention to safety, effective dose and side effects.
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Affiliation(s)
| | - Lida Jarahi
- Department of Community Medicine, Faculty of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Holger Cramer
- Department of Internal and Integrative Medicine, Kliniken Essen-Mitte, Faculty of Medicine, University of Duisburg-Essen, Essen, Germany
| | - Mohammad Safarian
- Metabolic Syndrome Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran; Department of Nutrition, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Hamideh Naghedi-Baghdar
- School of Persian and Complementary Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Roshanak Salari
- Department of Pharmaceutical Sciences in Persian Medicine, School of Persian and Complementary Medicine, Mashhad University of Medical Sciences, Mashhad, Iran
| | - Pardis Behravanrad
- Student of Veterinary Medicine, Islamic Azad University, Science and Research Branch, Tehran, Iran
| | - Hoda Azizi
- Department of Chinese and Complementary Medicine, School of Persian and Complementary Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
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Mayengbam S, Lambert JE, Parnell JA, Tunnicliffe JM, Nicolucci AC, Han J, Sturzenegger T, Shearer J, Mickiewicz B, Vogel HJ, Madsen KL, Reimer RA. Impact of dietary fiber supplementation on modulating microbiota-host-metabolic axes in obesity. J Nutr Biochem 2019; 64:228-236. [PMID: 30572270 DOI: 10.1016/j.jnutbio.2018.11.003] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2018] [Revised: 10/31/2018] [Accepted: 11/13/2018] [Indexed: 12/20/2022]
Abstract
Low dietary fiber intake is associated with higher rates of microbiota-associated chronic diseases such as obesity. Low-fiber diets alter not only microbial composition but also the availability of metabolic end products derived from fermentation of fiber. Our objective was to examine the effects of dietary fiber supplementation on gut microbiota and associated fecal and serum metabolites in relation to metabolic markers of obesity. We conducted a 12-week, single-center, double-blind, placebo-controlled trial with 53 adults with overweight or obesity. They were randomly assigned to a pea fiber (PF, 15 g/d in wafer form; n=29) or control (CO, isocaloric amount of wafers; n=24) group. Blood and fecal samples were collected at baseline and 12 weeks. Serum metabolomics, gut microbiota and fecal short-chain fatty acids (SCFAs) and bile acids (BAs) were examined. Within-group but not between-group analysis showed a significant effect of treatment on serum metabolites at 12 weeks compared to baseline. Fiber significantly altered fecal SCFAs and BAs with higher acetate and reduced isovalerate, cholate, deoxycholate and total BAs content in the PF group compared to baseline. Microbiota was differentially modulated in the two groups, including an increase in the SCFA producer Lachnospira in the PF group and decrease in the CO group. The change in body weight of participants showed a negative correlation with their change in Lachnospira (r=-0.463, P=.006) abundance. The current study provides insight into the actions of pea fiber and its impact on modulating microbiota-host-metabolic axes in obesity.
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Affiliation(s)
- Shyamchand Mayengbam
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Jennifer E Lambert
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Jill A Parnell
- Health and Physical Education, Mount Royal University, 4825 Mount Royal Gate SW, Calgary, AB, Canada, T3E 6K6
| | - Jasmine M Tunnicliffe
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Alissa C Nicolucci
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4
| | - Jay Han
- Food Processing Development Centre, Alberta Agriculture and Forestry, 6309-45 Street, Leduc, AB, Canada, T9E 7C5
| | - Troy Sturzenegger
- Food Processing Development Centre, Alberta Agriculture and Forestry, 6309-45 Street, Leduc, AB, Canada, T9E 7C5
| | - Jane Shearer
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4; Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, Canada, T2N 4N1
| | - Beata Mickiewicz
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - Hans J Vogel
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada, T2N 1N4
| | - Karen L Madsen
- Division of Gastroenterology, Centre of Excellence for Gastrointestinal Inflammation and Immunity Research, 7-142 Katz Group-Rexall Centre, University of Alberta, Edmonton, AB, Canada, T6G 2C2
| | - Raylene A Reimer
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB, Canada, T2N 1N4; Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, Canada, T2N 4N1.
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Hume MP, Nicolucci AC, Reimer RA. Prebiotic supplementation improves appetite control in children with overweight and obesity: a randomized controlled trial. Am J Clin Nutr 2017; 105:790-799. [PMID: 28228425 DOI: 10.3945/ajcn.116.140947] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Accepted: 01/26/2017] [Indexed: 11/14/2022] Open
Abstract
Background: Prebiotics have been shown to improve satiety in adults with overweight and obesity; however, studies in children are limited.Objective: We examined the effects of prebiotic supplementation on appetite control and energy intake in children with overweight and obesity.Design: This study was a randomized, double-blind, placebo-controlled trial. Forty-two boys and girls, ages 7-12 y, with a body mass index (BMI) of ≥85th percentile were randomly assigned to 8 g oligofructose-enriched inulin/d or placebo (maltodextrin) for 16 wk. Objective measures of appetite included energy intake at an ad libitum breakfast buffet, 3-d food records, and fasting satiety hormone concentrations. Subjective appetite ratings were obtained from visual analog scales before and after the breakfast. Children's Eating Behavior Questionnaires were also completed by caregivers.Results: Compared with placebo, prebiotic intake resulted in significantly higher feelings of fullness (P = 0.04) and lower prospective food consumption (P = 0.03) at the breakfast buffet at 16 wk compared with baseline. Compared with placebo, prebiotic supplementation significantly reduced energy intake at the week 16 breakfast buffet in 11- and 12-y-olds (P = 0.04) but not in 7- to 10-y-olds. Fasting adiponectin (P = 0.04) and ghrelin (P = 0.03) increased at 16 wk with the prebiotic compared with placebo. In intent-to-treat analysis, there was a trend for prebiotic supplementation to reduce BMI z score to a greater extent than placebo (-3.4%; P = 0.09) and a significant -3.8% reduction in per-protocol analysis (P = 0.043).Conclusions: Independent of other lifestyle changes, prebiotic supplementation in children with overweight and obesity improved subjective appetite ratings. This translated into reduced energy intake in a breakfast buffet in older but not in younger children. This simple dietary change has the potential to help with appetite regulation in children with obesity. This trial was registered at clinicaltrials.gov as NCT02125955.
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Affiliation(s)
| | | | - Raylene A Reimer
- Faculty of Kinesiology and .,Department of Biochemistry and Molecular Biology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
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Lambert JE, Parnell JA, Tunnicliffe JM, Han J, Sturzenegger T, Reimer RA. Consuming yellow pea fiber reduces voluntary energy intake and body fat in overweight/obese adults in a 12-week randomized controlled trial. Clin Nutr 2017; 36:126-133. [PMID: 26811130 DOI: 10.1016/j.clnu.2015.12.016] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Revised: 12/09/2015] [Accepted: 12/28/2015] [Indexed: 01/07/2023]
Abstract
BACKGROUND & AIMS The purpose of this randomized, double-blind, placebo-controlled study was to assess the effects of yellow pea fiber intake on body composition and metabolic markers in overweight/obese adults. METHODS Participants (9 M/41 F; age 44 ± 15 y, BMI 32.9 ± 5.9 kg/m2) received isocaloric doses of placebo (PL) or pea fiber (PF; 15 g/d) wafers for 12 weeks. Outcome measures included changes in anthropometrics, body composition (DXA), oral glucose tolerance test (OGTT), food intake (ad libitum lunch buffet), and biochemical indices. RESULTS The PF group lost 0.87 ± 0.37 kg of body weight, primarily due to body fat (-0.74 ± 0.26 kg), whereas PL subjects gained 0.40 ± 0.39 kg of weight over the 12 weeks (P = 0.022). The PF group consumed 16% less energy at the follow-up lunch buffet (P = 0.026), whereas the PL group did not change. During the OGTT, glucose area under the curve (AUC) was lower in PF subjects at follow-up (P = 0.029); insulin increased in both groups over time (P = 0.008), but more so in the PL group (38% higher AUC vs. 10% higher in the PF group). There were no differences in gut microbiota between groups. CONCLUSIONS In the absence of other lifestyle changes, incorporating 15 g/day yellow pea fiber may yield small but significant metabolic benefits and aid in obesity management. Clinical Trial Registry: ClinicalTrials.gov NCT01719900.
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Affiliation(s)
- Jennifer E Lambert
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
| | - Jill A Parnell
- Physical Education and Recreation Studies, Mount Royal University, 4825 Mount Royal Gate SW, Calgary, AB T3E 6K6, Canada.
| | - Jasmine M Tunnicliffe
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada.
| | - Jay Han
- Food Processing Development Centre, Alberta Agriculture and Rural Development, 6309 - 45 Street, Leduc, AB T9E 7C5, Canada.
| | - Troy Sturzenegger
- Food Processing Development Centre, Alberta Agriculture and Rural Development, 6309 - 45 Street, Leduc, AB T9E 7C5, Canada.
| | - Raylene A Reimer
- Faculty of Kinesiology, University of Calgary, 2500 University Drive NW, Calgary, AB T2N 1N4, Canada; Department of Biochemistry & Molecular Biology, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB T2N 4N1, Canada.
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Hartley L, May MD, Loveman E, Colquitt JL, Rees K. Dietary fibre for the primary prevention of cardiovascular disease. Cochrane Database Syst Rev 2016; 2016:CD011472. [PMID: 26758499 PMCID: PMC7032538 DOI: 10.1002/14651858.cd011472.pub2] [Citation(s) in RCA: 68] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
BACKGROUND The prevention of cardiovascular disease (CVD) is a key public health priority. A number of dietary factors have been associated with modifying CVD risk factors. One such factor is dietary fibre which may have a beneficial association with CVD risk factors. There is a need to review the current evidence from randomised controlled trials (RCTs) in this area. OBJECTIVES The primary objective of this systematic review was to determine the effectiveness of dietary fibre for the primary prevention of CVD. SEARCH METHODS We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, Ovid MEDLINE (1946 to January 2015), Ovid EMBASE (1947 to January 2015) and Science Citation Index Expanded (1970 to January 2015) as well as two clinical trial registers in January 2015. We also checked reference lists of relevant articles. No language restrictions were applied. SELECTION CRITERIA We selected RCTs that assessed the effects of dietary fibre compared with no intervention or a minimal intervention on CVD and related risk factors. Participants included adults who are at risk of CVD or those from the general population. DATA COLLECTION AND ANALYSIS Two authors independently selected studies, extracted data and assessed risk of bias; a third author checked any differences. A different author checked analyses. MAIN RESULTS We included 23 RCTs (1513 participants randomised) examining the effect of dietary fibre. The risk of bias was unclear for most studies and studies had small sample sizes. Few studies had an intervention duration of longer than 12 weeks. There was a wide variety of fibre sources used, with little similarity between groups in the choice of intervention.None of the studies reported on mortality (total or cardiovascular) or cardiovascular events. Results on lipids suggest there is a significant beneficial effect of increased fibre on total cholesterol levels (17 trials (20 comparisons), 1067 participants randomised, mean difference -0.23 mmol/L, 95% CI -0.40 to -0.06), and LDL cholesterol levels (mean difference -0.14 mmol/L, 95% CI -0.22 to -0.06) but not on triglyceride levels (mean difference 0.00 mmol/L, 95% CI -0.04 to 0.05), and there was a very small but statistically significant decrease rather than increase in HDL levels with increased fibre intake (mean difference -0.03 mmol/L, 95% CI -0.06 to -0.01). Fewer studies (10 trials, 661 participants randomised) reported blood pressure outcomes where there is a significant effect of increased fibre consumption on diastolic blood pressure (mean difference -1.77 mmHg, 95% CI -2.61 to -0.92) whilst there is a reduction in systolic blood pressure with fibre but this does not reach statistical significance (mean difference -1.92 mmHg, 95% CI -4.02 to 0.19). There did not appear to be any subgroup effects by the nature of the type of intervention (fibre supplements or provision of foods/advice to increase fibre consumption) or the type of fibre (soluble/insoluble) although the number of studies contributing to each subgroup were small. All analyses need to be viewed with caution given the risks of bias observed for total cholesterol and the statistical heterogeneity observed for systolic blood pressure. Adverse events, where reported, appeared to mostly reflect mild to moderate gastrointestinal side-effects and these were generally reported more in the fibre intervention groups than the control groups. AUTHORS' CONCLUSIONS Studies were short term and therefore did not report on our primary outcomes, CVD clinical events. The pooled analyses for CVD risk factors suggest reductions in total cholesterol and LDL cholesterol with increased fibre intake, and reductions in diastolic blood pressure. There were no obvious effects of subgroup analyses by type of intervention or fibre type but the number of studies included in each of these analyses were small. Risk of bias was unclear in the majority of studies and high for some quality domains so results need to be interpreted cautiously. There is a need for longer term, well-conducted RCTs to determine the effects of fibre type (soluble versus insoluble) and administration (supplements versus foods) on CVD events and risk factors for the primary prevention of CVD.
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Affiliation(s)
- Louise Hartley
- Warwick Medical School, University of WarwickDivision of Health SciencesCoventryWarwickshireUKCV4 7AL
| | - Michael D May
- University of WarwickWarwick Medical SchoolWarwickUK
| | - Emma Loveman
- Effective Evidence LLP7 Bournemouth RoadEastleighHampshireUKSO53 3DA
| | - Jill L Colquitt
- Effective Evidence LLP7 Bournemouth RoadEastleighHampshireUKSO53 3DA
| | - Karen Rees
- Warwick Medical School, University of WarwickDivision of Health SciencesCoventryWarwickshireUKCV4 7AL
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