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The Proceedings of the Nutrition Society Feb 2003Establishing a definition for dietary fibre has historically been a balance between nutrition knowledge and analytical method capabilities. While the most widely... (Review)
Review
Establishing a definition for dietary fibre has historically been a balance between nutrition knowledge and analytical method capabilities. While the most widely accepted physiologically-based definitions have generally been accurate in defining the dietary fibre in foods, scientists and regulators have tended, in practice, to rely on analytical procedures as the definitional basis in fact. As a result, incongruities between theory and practice have resulted in confusion regarding the components that make up dietary fibre. In November 1998 the president of the American Association of Cereal Chemists (AACC) appointed an expert scientific review committee and charged it with the task of reviewing and, if necessary, updating the definition of dietary fibre. The committee was further charged with assessing the state of analytical methodology and making recommendations relevant to the updated definition. After due deliberation, an updated definition of dietary fibre was delivered to the AACC Board of Directors for consideration and adoption (Anon, 2000; Jones 2000b). The updated definition includes the same food components as the historical working definition used for approximately 30 years (a very important point, considering that the majority of the research of the past 30 years delineating the positive health effects of dietary fibre is based on that working definition). However, the updated definition more clearly delineates the make-up of dietary fibre and its physiological functionality. As a result, relatively few changes will be necessary in analytical methodology. Current methodologies, in particular AACC-approved method of analysis 32-05 (Grami, 2000), Association of Official Analytical Chemists' official method of analysis 985.29 (Horwitz, 2000a) or AACC 32-07 (Grami, 2000) Association of Official Analytical Chemists 991.43 (Horwitz, 2000a) will continue to be sufficient and used for most foods. A small number of additional methods will be necessary to quantify the dietary fibre levels in foods containing fibres such as fructans (polymers and oligomers of fructose, inulin), modified dextrins, and/or synthetic dietary fibre analogues.
Topics: Chemistry Techniques, Analytical; Dietary Fiber; Food Analysis; Health Promotion; Humans; Lignin; Societies
PubMed: 12740055
DOI: 10.1079/PNS2002234 -
Journal of Proteomics Sep 2023The high purity insoluble dietary fiber (IDF) from okara is a natural component with a potentially positive effect on a high-fat diet (HFD)-induced hepatic metabolic...
Label-free quantitative proteomics reveals the potential mechanisms of insoluble dietary fiber from okara in improving hepatic lipid metabolism of high-fat diet-induced mice.
The high purity insoluble dietary fiber (IDF) from okara is a natural component with a potentially positive effect on a high-fat diet (HFD)-induced hepatic metabolic disorders, although its regulatory mechanism remains unclear. This study aims to elucidate the potential pathways and key proteins of IDF for the amelioration of hepatic lipid metabolism in mice fed with HFD. Here, we used label-free quantitative proteomics technology to quantity and identify differentially expressed proteins in the liver that are associated with IDF treatment. The differentially expressed proteins were assessed by GO annotation and KEGG pathways. Western blot and qRT-PCR analyses were conducted to validate the potential targets regulated by IDF. In total, 73 differentially expressed proteins were identified, of which 27 were up-regulated (FC > 1.5) and 46 were down-regulated (FC < 0.667). GO analysis suggested that differentially expressed proteins were mainly located in the cell and organelles, regulated biological processes, and were associated with enzyme activity and molecular binding. The KEGG pathway enrichment analysis further demonstrated glycolysis/gluconeogenesis, pyruvate metabolism, TCA cycle, arginine biosynthesis, alanine, aspartate and glutamate metabolism, and retinol metabolism were affected. The combination of proteomics, Western blot, and qRT-PCR suggested that ACS, ACLY, GOT1, GLS2, NAGS, CYP4A10, CYP3A25, and CYP2A5 in these pathways might be key proteins for IDF intervention. Taken together, our findings elucidate new mechanisms involved in how IDF affects hepatic metabolism, provide important information for the functional food industries, and improve the added value of okara. SIGNIFICANCE: Okara is evidenced as a high-quality by-product with several nutritional components, especially dietary fiber (50-60%) labeled as "The Seventh Nutrient". Previous studies have shown that IDF has a positive potential effect on a high-fat diet (HFD)-induced hepatic metabolic disorders, but its molecular mechanism remains unclear. To elucidate the therapeutic mechanism of IDF at the protein level, a label-free quantitative proteomic analysis was used to identify the dynamic changes of the liver proteome between HIDF and HFD groups in this study. These results provide a new perspective for exploring the therapeutic mechanism of IDF at the protein level and enlightenment for promoting the comprehensive utilization of okara.
Topics: Mice; Animals; Lipid Metabolism; Diet, High-Fat; Proteomics; Liver; Proteins; Dietary Fiber
PubMed: 37499746
DOI: 10.1016/j.jprot.2023.104980 -
The Medical Journal of Australia Aug 1990
Topics: Cholesterol; Dietary Fiber; Edible Grain; Humans; Oryza; Triticum
PubMed: 2165556
DOI: 10.5694/j.1326-5377.1990.tb136825.x -
The Proceedings of the Nutrition Society Jan 1981
Review
Topics: Animals; Carcinogens; Cellulose; Colonic Neoplasms; Diet; Dietary Fiber; Disease Models, Animal; Feces; Gastrointestinal Motility; Humans; Intestinal Diseases; Intestinal Neoplasms; Intestine, Large; Molecular Biology; Neoplasms, Experimental
PubMed: 6259640
DOI: 10.1079/pns19810003 -
The British Journal of Nutrition Apr 2013As bread is the most relevant source of available carbohydrates in the diet and as lowering dietary glycaemic index (GI) is considered favourable to health, many studies... (Review)
Review
As bread is the most relevant source of available carbohydrates in the diet and as lowering dietary glycaemic index (GI) is considered favourable to health, many studies have been carried out in order to decrease the GI of bread. The most relevant strategy that has been applied so far is the addition of fibre-rich flours or pure dietary fibre. However, the effectiveness of dietary fibre in bread in reducing the GI is controversial. The purpose of the present review was to discuss critically the effects obtained by adding different kinds of fibre to bread in order to modulate its glycaemic response. The studies were selected because they analysed in vivo whether or not dietary fibre, naturally present or added during bread making, could improve the glucose response. The reviewed literature suggests that the presence of intact structures not accessible to human amylases, as well as a reduced pH that may delay gastric emptying or create a barrier to starch digestion, seems to be more effective than dietary fibre per se in improving glucose metabolism, irrespective of the type of cereal. Moreover, the incorporation of technologically extracted cereal fibre fractions, the addition of fractions from legumes or of specifically developed viscous or non-viscous fibres also constitute effective strategies. However, when fibres or wholemeal is included in bread making to affect the glycaemic response, the manufacturing protocol needs to reconsider several technological parameters in order to obtain high-quality and consumer-acceptable breads.
Topics: Bread; Dietary Fiber; Fermentation; Food Handling; Food Quality; Glycemic Index; Humans; Hyperglycemia; Starch; Viscosity
PubMed: 23414580
DOI: 10.1017/S0007114513000032 -
The Cochrane Database of Systematic... Jan 2017This is an update of the Cochrane review published in 2002.Colorectal cancer (CRC) is a major cause of morbidity and mortality in industrialised countries. Experimental... (Review)
Review
BACKGROUND
This is an update of the Cochrane review published in 2002.Colorectal cancer (CRC) is a major cause of morbidity and mortality in industrialised countries. Experimental evidence has supported the hypothesis that dietary fibre may protect against the development of CRC, although epidemiologic data have been inconclusive.
OBJECTIVES
To assess the effect of dietary fibre on the recurrence of colorectal adenomatous polyps in people with a known history of adenomatous polyps and on the incidence of CRC compared to placebo. Further, to identify the reported incidence of adverse effects, such as abdominal pain or diarrhoea, that resulted from the fibre intervention.
SEARCH METHODS
We identified randomised controlled trials (RCTs) from Cochrane Colorectal Cancer's Specialised Register, CENTRAL, MEDLINE and Embase (search date, 4 April 2016). We also searched ClinicalTrials.gov and WHO International Trials Registry Platform on October 2016.
SELECTION CRITERIA
We included RCTs or quasi-RCTs. The population were those having a history of adenomatous polyps, but no previous history of CRC, and repeated visualisation of the colon/rectum after at least two-years' follow-up. Dietary fibre was the intervention. The primary outcomes were the number of participants with: 1. at least one adenoma, 2. more than one adenoma, 3. at least one adenoma greater than or equal to 1 cm, or 4. a new diagnosis of CRC. The secondary outcome was the number of adverse events.
DATA COLLECTION AND ANALYSIS
Two reviewers independently extracted data, assessed trial quality and resolved discrepancies by consensus. We used risk ratios (RR) and risk difference (RD) with 95% confidence intervals (CI) to measure the effect. If statistical significance was reached, we reported the number needed to treat for an additional beneficial outcome (NNTB) or harmful outcome (NNTH). We combined the study data using the fixed-effect model if it was clinically, methodologically, and statistically reasonable.
MAIN RESULTS
We included seven studies, of which five studies with 4798 participants provided data for analyses in this review. The mean ages of the participants ranged from 56 to 66 years. All participants had a history of adenomas, which had been removed to achieve a polyp-free colon at baseline. The interventions were wheat bran fibre, ispaghula husk, or a comprehensive dietary intervention with high fibre whole food sources alone or in combination. The comparators were low-fibre (2 to 3 g per day), placebo, or a regular diet. The combined data showed no statistically significant difference between the intervention and control groups for the number of participants with at least one adenoma (5 RCTs, n = 3641, RR 1.04, 95% CI 0.95 to 1.13, low-quality evidence), more than one adenoma (2 RCTs, n = 2542, RR 1.06, 95% CI 0.94 to 1.20, low-quality evidence), or at least one adenoma 1 cm or greater (4 RCTs, n = 3224, RR 0.99, 95% CI 0.82 to 1.20, low-quality evidence) at three to four years. The results on the number of participants diagnosed with colorectal cancer favoured the control group over the dietary fibre group (2 RCTS, n = 2794, RR 2.70, 95% CI 1.07 to 6.85, low-quality evidence). After 8 years of comprehensive dietary intervention, no statistically significant difference was found in the number of participants with at least one recurrent adenoma (1 RCT, n = 1905, RR 0.97, 95% CI 0.78 to 1.20), or with more than one adenoma (1 RCT, n = 1905, RR 0.89, 95% CI 0.64 to 1.24). More participants given ispaghula husk group had at least one recurrent adenoma than the control group (1 RCT, n = 376, RR 1.45, 95% CI 1.01 to 2.08). Other analyses by types of fibre intervention were not statistically significant. The overall dropout rate was over 16% in these trials with no reasons given for these losses. Sensitivity analysis incorporating these missing data shows that none of the results can be considered as robust; when the large numbers of participants lost to follow-up were assumed to have had an event or not, the results changed sufficiently to alter the conclusions that we would draw. Therefore, the reliability of the findings may have been compromised by these missing data (attrition bias) and should be interpreted with caution.
AUTHORS' CONCLUSIONS
There is a lack of evidence from existing RCTs to suggest that increased dietary fibre intake will reduce the recurrence of adenomatous polyps in those with a history of adenomatous polyps within a two to eight year period. However, these results may be unreliable and should be interpreted cautiously, not only because of the high rate of loss to follow-up, but also because adenomatous polyp is a surrogate outcome for the unobserved true endpoint CRC. Longer-term trials with higher dietary fibre levels are needed to enable confident conclusion.
Topics: Adenoma; Adenomatous Polyps; Aged; Colorectal Neoplasms; Dietary Fiber; Humans; Middle Aged; Neoplasm Recurrence, Local; Randomized Controlled Trials as Topic
PubMed: 28064440
DOI: 10.1002/14651858.CD003430.pub2 -
Nutrients Oct 2022Diabetes is the leading cause of kidney disease, and as the number of individuals with diabetes increases there is a concomitant increase in the prevalence of diabetic... (Review)
Review
Diabetes is the leading cause of kidney disease, and as the number of individuals with diabetes increases there is a concomitant increase in the prevalence of diabetic kidney disease (DKD). Diabetes contributes to the development of DKD through a number of pathways, including inflammation, oxidative stress, and the gut-kidney axis, which may be amenable to dietary therapy. Resistant starch (RS) is a dietary fibre that alters the gut microbial consortium, leading to an increase in the microbial production of short chain fatty acids. Evidence from animal and human studies indicate that short chain fatty acids are able to attenuate inflammatory and oxidative stress pathways, which may mitigate the progression of DKD. In this review, we evaluate and summarise the evidence from both preclinical models of DKD and clinical trials that have utilised RS as a dietary therapy to limit the progression of DKD.
Topics: Animals; Humans; Resistant Starch; Starch; Diabetic Nephropathies; Dietary Fiber; Fatty Acids, Volatile; Diabetes Mellitus
PubMed: 36364808
DOI: 10.3390/nu14214547 -
Journal of Internal Medicine Jun 1993
Topics: Diabetes Mellitus; Dietary Fiber; Gastrointestinal Diseases; Humans; Lipids; Obesity
PubMed: 8388912
DOI: 10.1111/j.1365-2796.1993.tb00996.x -
Nature Food Jan 2023
Topics: Dietary Fiber
PubMed: 37118563
DOI: 10.1038/s43016-022-00674-w -
European Journal of Cancer Prevention :... Oct 1997Early epidemiological studies suggested that dietary fibre could be protective against colon cancer. Many isolated fibres were tested for anticarcinogenic activity in... (Review)
Review
Early epidemiological studies suggested that dietary fibre could be protective against colon cancer. Many isolated fibres were tested for anticarcinogenic activity in carcinogen-treated rats. Wheat bran was consistently protective. Some human studies suggest that dietary wheat bran may protect against growth of colon adenomas. The precise mechanism by which fibre exerts its effects is still elusive. Fibre exerts many influences in the digestive tract. It can dilute the tract contents, and studies show that decreased concentration of faecal bile acids is correlated with reduced cancer risk. Fibre may enhance energy excretion and caloric intake has been correlated positively with cancer risk. Bacterial degradation of fibre produces, among other compounds, butyric acid which may affect colonic and faecal pH and also shows antiproliferative activity. More data are needed vis-à-vis effects of dietary fibre on human colon cancer. These should include studies of specific fibres as well as of high fibre diets. The mechanism(s) of fibre action, including effects on oncogenes, steroid metabolites and short chain fatty acids, requires elucidation.
Topics: Animals; Anticarcinogenic Agents; Colorectal Neoplasms; Dietary Fiber; Epidemiologic Studies; Humans; Rats; Triticum
PubMed: 9466115
DOI: 10.1097/00008469-199710000-00004