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Effect of low glycaemic index or load dietary patterns on glycaemic control and cardiometabolic risk factors in diabetes: systematic review and meta-analysis of randomised controlled trials.
Chiavaroli, L, Lee, D, Ahmed, A, Cheung, A, Khan, TA, Blanco, S, Mejia, , Mirrahimi, A, Jenkins, DJA, Livesey, G, et al
BMJ (Clinical research ed.). 2021;:n1651
Abstract
OBJECTIVE To inform the update of the European Association for the Study of Diabetes clinical practice guidelines for nutrition therapy. DESIGN Systematic review and meta-analysis of randomised controlled trials. DATA SOURCES Medline, Embase, and the Cochrane Library searched up to 13 May 2021. ELIGIBILITY CRITERIA FOR SELECTING STUDIES Randomised controlled trials of three or more weeks investigating the effect of diets with low glycaemic index (GI)/glycaemic load (GL) in diabetes. OUTCOME AND MEASURES The primary outcome was glycated haemoglobin (HbA1c). Secondary outcomes included other markers of glycaemic control (fasting glucose, fasting insulin); blood lipids (low density lipoprotein cholesterol (LDL-C), high density lipoprotein cholesterol (HDL-C), non-HDL-C, apo B, triglycerides); adiposity (body weight, BMI (body mass index), waist circumference), blood pressure (systolic blood pressure (SBP) and diastolic blood pressure (DBP)), and inflammation (C reactive protein (CRP)). DATA EXTRACTION AND SYNTHESIS Two independent reviewers extracted data and assessed risk of bias. Data were pooled by random effects models. GRADE (grading of recommendations assessment, development, and evaluation) was used to assess the certainty of evidence. RESULTS 29 trial comparisons were identified in 1617 participants with type 1 and 2 diabetes who were predominantly middle aged, overweight, or obese with moderately controlled type 2 diabetes treated by hyperglycaemia drugs or insulin. Low GI/GL dietary patterns reduced HbA1c in comparison with higher GI/GL control diets (mean difference −0.31% (95% confidence interval −0.42 to −0.19%), P<0.001; substantial heterogeneity, I2=75%, P<0.001). Reductions occurred also in fasting glucose, LDL-C, non-HDL-C, apo B, triglycerides, body weight, BMI, systolic blood pressure (dose-response), and CRP (P<0.05), but not blood insulin, HDL-C, waist circumference, or diastolic blood pressure. A positive dose-response gradient was seen for the difference in GL and HbA1c and for absolute dietary GI and SBP (P<0.05). The certainty of evidence was high for the reduction in HbA1c and moderate for most secondary outcomes, with downgrades due mainly to imprecision. CONCLUSIONS This synthesis suggests that low GI/GL dietary patterns result in small important improvements in established targets of glycaemic control, blood lipids, adiposity, blood pressure, and inflammation beyond concurrent treatment with hyperglycaemia drugs or insulin, predominantly in adults with moderately controlled type 1 and type 2 diabetes. The available evidence provides a good indication of the likely benefit in this population. STUDY REGISTRATION ClinicalTrials.gov NCT04045938.
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Dietary Glycaemic Index Labelling: A Global Perspective.
Barclay, AW, Augustin, LSA, Brighenti, F, Delport, E, Henry, CJ, Sievenpiper, JL, Usic, K, Yuexin, Y, Zurbau, A, Wolever, TMS, et al
Nutrients. 2021;(9)
Abstract
The glycaemic index (GI) is a food metric that ranks the acute impact of available (digestible) carbohydrates on blood glucose. At present, few countries regulate the inclusion of GI on food labels even though the information may assist consumers to manage blood glucose levels. Australia and New Zealand regulate GI claims as nutrition content claims and also recognize the GI Foundation's certified Low GI trademark as an endorsement. The GI Foundation of South Africa endorses foods with low, medium and high GI symbols. In Asia, Singapore's Healthier Choice Symbol has specific provisions for low GI claims. Low GI claims are also permitted on food labels in India. In China, there are no national regulations specific to GI; however, voluntary claims are permitted. In the USA, GI claims are not specifically regulated but are permitted, as they are deemed to fall under general food-labelling provisions. In Canada and the European Union, GI claims are not legal under current food law. Inconsistences in food regulation around the world undermine consumer and health professional confidence and call for harmonization. Global provisions for GI claims/endorsements in food standard codes would be in the best interests of people with diabetes and those at risk.
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Coronary Heart Disease and Dietary Carbohydrate, Glycemic Index, and Glycemic Load: Dose-Response Meta-analyses of Prospective Cohort Studies.
Livesey, G, Livesey, H
Mayo Clinic proceedings. Innovations, quality & outcomes. 2019;(1):52-69
Abstract
OBJECTIVE To clarify the role of dietary carbohydrate, glycemic index (GI), and glycemic load (GL) in progression from health to coronary heart disease (CHD) by determining disease-nutrient risk relation (RR) values needed for intake ranges within jurisdictions and across the globe. METHODS We performed a literature search of MEDLINE and EMBASE for prospective cohort studies that used truly valid dietary instruments in heathy adults published from January 1, 2000, to June 5, 2018. Relevant observations were extracted by 2 reviewers independently. We used dose-response meta-analysis accounting for nonindependence of results within studies. Bradford-Hill criteria were used to assess causality. RESULTS Eligible studies had a mean follow-up of 11 years (range, 5-19 years), were conducted in North America, Europe, and East Asia, and yielded combined RRs of 1.44 (95% CI, 1.25-1.65) per 65 g/d GL (11 studies) and 1.24 (95% CI, 1.12-1.38) per 10 U GI (10 studies) (glucose scale). The CHD-carbohydrate RR on GI was 1.66 (95% CI, 1.23-2.25) per 98 g/d of carbohydrates per 10 units GI. The 65 g/d GL, 10 U GI, and 98 g/d carbohydrate values corresponded to oral intakes from the 10th to the 90th percentiles within sampled populations. Inconsistencies were minor (I 2 ≤20%), as were small-study effects (P=.61 for GL and P=.26 for GI). Funnel plots were symmetric. Cubic spline dose-response meta-analysis yielded RRs as follows: across the global range for GL (55-290 g/d), 5.5 (95% CI, 3.1-9.8) (I 2 =0); for GI (47-82 U), 2.71 (95% CI, 1.47-4.40) (I 2 =0); and for the CHD-carbohydrate dependence on GI (50-80 U), 4.57 (95% CI, 1.86-11.4) (I 2 =16%). Bradford-Hill criteria indicated that these relations were probably causal. CONCLUSION Strong and probably causal CHD-GL and GI RRs exist within populations. The RRs were remarkably higher across global exposures. The results support the consideration of these markers of carbohydrate food quality in dietary guidelines for general populations. TRIAL REGISTRATION PROSPERO Identifier: CRD42013004504.
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Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: A Systematic Review and Updated Meta-Analyses of Prospective Cohort Studies.
Livesey, G, Taylor, R, Livesey, HF, Buyken, AE, Jenkins, DJA, Augustin, LSA, Sievenpiper, JL, Barclay, AW, Liu, S, Wolever, TMS, et al
Nutrients. 2019;(6)
Abstract
Published meta-analyses indicate significant but inconsistent incident type-2 diabetes(T2D)-dietary glycemic index (GI) and glycemic load (GL) risk ratios or risk relations (RR). It is nowover a decade ago that a published meta-analysis used a predefined standard to identify validstudies. Considering valid studies only, and using random effects dose-response meta-analysis(DRM) while withdrawing spurious results (p < 0.05), we ascertained whether these relationswould support nutrition guidance, specifically for an RR > 1.20 with a lower 95% confidence limit>1.10 across typical intakes (approximately 10th to 90th percentiles of population intakes). Thecombined T2D-GI RR was 1.27 (1.15-1.40) (p < 0.001, n = 10 studies) per 10 units GI, while that forthe T2D-GL RR was 1.26 (1.15-1.37) (p < 0.001, n = 15) per 80 g/d GL in a 2000 kcal (8400 kJ) diet.The corresponding global DRM using restricted cubic splines were 1.87 (1.56-2.25) (p < 0.001, n =10) and 1.89 (1.66-2.16) (p < 0.001, n = 15) from 47.6 to 76.1 units GI and 73 to 257 g/d GL in a 2000kcal diet, respectively. In conclusion, among adults initially in good health, diets higher in GI or GLwere robustly associated with incident T2D. Together with mechanistic and other data, thissupports that consideration should be given to these dietary risk factors in nutrition advice.Concerning the public health relevance at the global level, our evidence indicates that GI and GLare substantial food markers predicting the development of T2D worldwide, for persons ofEuropean ancestry and of East Asian ancestry.
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Glycemic index, glycemic load and glycemic response: An International Scientific Consensus Summit from the International Carbohydrate Quality Consortium (ICQC).
Augustin, LSA, Kendall, CWC, Jenkins, DJA, Willett, WC, Astrup, A, Barclay, AW, Björck, I, Brand-Miller, JC, Brighenti, F, Buyken, AE, et al
Nutrition, metabolism, and cardiovascular diseases : NMCD. 2015;(9):795-815
Abstract
BACKGROUND AND AIMS The positive and negative health effects of dietary carbohydrates are of interest to both researchers and consumers. METHODS International experts on carbohydrate research held a scientific summit in Stresa, Italy, in June 2013 to discuss controversies surrounding the utility of the glycemic index (GI), glycemic load (GL) and glycemic response (GR). RESULTS The outcome was a scientific consensus statement which recognized the importance of postprandial glycemia in overall health, and the GI as a valid and reproducible method of classifying carbohydrate foods for this purpose. There was consensus that diets low in GI and GL were relevant to the prevention and management of diabetes and coronary heart disease, and probably obesity. Moderate to weak associations were observed for selected cancers. The group affirmed that diets low in GI and GL should always be considered in the context of diets otherwise understood as healthy, complementing additional ways of characterizing carbohydrate foods, such as fiber and whole grain content. Diets of low GI and GL were considered particularly important in individuals with insulin resistance. CONCLUSIONS Given the high prevalence of diabetes and pre-diabetes worldwide and the consistency of the scientific evidence reviewed, the expert panel confirmed an urgent need to communicate information on GI and GL to the general public and health professionals, through channels such as national dietary guidelines, food composition tables and food labels.
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Is there a dose-response relation of dietary glycemic load to risk of type 2 diabetes? Meta-analysis of prospective cohort studies.
Livesey, G, Taylor, R, Livesey, H, Liu, S
The American journal of clinical nutrition. 2013;(3):584-96
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BACKGROUND Although much is known about the association between dietary glycemic load (GL) and type 2 diabetes (T2D), prospective cohort studies have not consistently shown a positive dose-response relation. OBJECTIVE We performed a comprehensive examination of evidence on the dose response that links GL to T2D and sources of heterogeneity among all prospective cohort studies on healthy adults available in the literature. DESIGN We conducted a systematic review of all prospective cohort studies and meta-analyses to quantify the GL-T2D relation both without and with adjustment for covariates. RESULTS Among 24 prospective cohort studies identified by August 2012, the GL ranged from ∼60 to ∼280 g per daily intake of 2000 kcal (8.4 MJ). In a fully adjusted meta-analysis model, the GL was positively associated with RR of T2D of 1.45 (95% CI: 1.31, 1.61) for a 100-g increment in GL (P < 0.001; n = 24 studies; 7.5 million person-years of follow-up). Sex (P = 0.03), dietary instrument validity (P < 0.001), and ethnicity (European American compared with other; P = 0.04) together explained 97% of the heterogeneity among studies. After adjustment for heterogeneities, we used both funnel and trim-and-fill analyses to identify a negligible publication bias. Multiple influence, cumulative, and forecast analyses indicated that the GL-T2D relation tended to have reached stability and to have been underestimated. The relation was apparent at all doses of GL investigated, although it was statistically significant only at >95 g GL/2000 kcal. CONCLUSION After we accounted for several sources of heterogeneity, findings from prospective cohort studies that related the GL to T2D appear robust and consistently indicate strong and significantly lower T2D risk in persons who consume lower-GL diets. This review was registered at http://www.crd.york.ac.uk/PROSPERO as CRD42011001810.
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Interventions to lower the glycemic response to carbohydrate foods with a low-viscosity fiber (resistant maltodextrin): meta-analysis of randomized controlled trials.
Livesey, G, Tagami, H
The American journal of clinical nutrition. 2009;(1):114-25
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BACKGROUND The glycemic response to diet has been linked with noncommunicable diseases and is reduced by low-palatable, viscous, soluble fiber (1). Whether a palatable, low-viscous, soluble fiber such as resistant maltodextrin (RMD) has the same effect is unclear. OBJECTIVE The objective was to assess evidence on the attenuation of the blood glucose response to foods by < or = 10 g RMD in healthy adults. DESIGN We conducted a systematic review of randomized, placebo-controlled trials with the use of fixed- and random-effects meta-analyses and meta-regression models. RESULTS We found data from 37 relevant trials to April 2007. These trials investigated the attenuation of the glycemic response to rice, noodles, pastry, bread, and refined carbohydrates that included 30-173 g available carbohydrate. RMD was administered in drinks or liquid foods or solid foods. Placebo drinks and foods excluded RMD. Percentage attenuation was significant, dose-dependent, and independent of the amount of available carbohydrate coingested. Attenuation of the glycemic response to starchy foods by 6 g RMD in drinks approached approximately 20%, but when placed directly into foods was approximately 10% -- significant (P < 0.001) by both modes of administration. Study quality analyses, funnel plots, and trim-and-fill analyses uncovered no cause of significant systematic bias. Studies from authors affiliated with organizations for-profit were symmetrical without heterogeneity, whereas marginal asymmetry and significant heterogeneity arose among studies involving authors from nonprofit organizations because of some imprecise studies. CONCLUSIONS A nonviscous palatable soluble polysaccharide can attenuate the glycemic response to carbohydrate foods. Evidence of an effect was stronger for RMD in drinks than in foods.
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Glycemic response and health--a systematic review and meta-analysis: the database, study characteristics, and macronutrient intakes.
Livesey, G, Taylor, R, Hulshof, T, Howlett, J
The American journal of clinical nutrition. 2008;(1):223S-236S
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BACKGROUND Reduction of dietary glycemic response has been proposed as a means of reducing the risk of diabetes and coronary heart disease. Its role in health maintenance and management, alongside unavailable carbohydrate (eg, fiber), is incompletely understood. OBJECTIVE We aimed to assess the evidence relating the glycemic impact of foods to a role in health maintenance and management of disease. DESIGN We searched the literature for relevant controlled dietary intervention trials on glycemic index (GI) according to inclusion and exclusion criteria, extracted the data to a database, and synthesized the evidence via meta-analyses and meta-regression models. RESULTS Among literature to January 2005, 45 relevant publications were identified involving 972 subjects with good health or metabolic disease. With small reductions in GI (<10 units), increases in available carbohydrate, energy, and protein intakes were found in all studies combined. Falling trends in energy, available carbohydrate, and protein intakes then occurred with progressive reductions in GI. Fat intake was essentially unchanged. Unavailable carbohydrate intake was generally higher for intervention diets but showed no trend with GI (falling or rising). Among studies reporting on GI, variation in glycemic load was approximately equally explained by variation in GI and variation in available carbohydrate intake. An exchange of available and unavailable carbohydrate (approximately 1 g/g) was evident in these studies. CONCLUSIONS Among GI studies, observed reductions in glycemic load are most often not solely due to substitution of high for low glycemic carbohydrate foods. Available carbohydrate intake is a confounding factor. The role of unavailable carbohydrate remains to be accounted for.
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Fructose consumption and consequences for glycation, plasma triacylglycerol, and body weight: meta-analyses and meta-regression models of intervention studies.
Livesey, G, Taylor, R
The American journal of clinical nutrition. 2008;(5):1419-37
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BACKGROUND The glycemic response to dietary fructose is low, which may improve concentrations of glycated hemoglobin (HbA(1c), a marker of dysglycemia). Meanwhile, adverse effects on plasma triacylglycerol (a marker of dyslipidemia) and body weight have been questioned. Such effects are reported inconsistently.
OBJECTIVE We aimed to evaluate the effect of fructose on these health markers, particularly examining treatment dose and duration, and level of glycemic control.
DESIGN A literature search was conducted for relevant randomized and controlled intervention studies of crystalline or pure fructose (excluding high-fructose corn syrup), data extraction, meta-analyses, and modeling using meta-regression.
RESULTS Fructose intake < 90 g/d significantly improved HbA(1c) concentrations dependent on the dose, the duration of study, and the continuous severity of dysglycemia throughout the range of dysglycemia. There was no significant change in body weight at intakes <100 g fructose/d. Fructose intakes of <50 g/d had no postprandially significant effect on triacylglycerol and those of
or=100 g fructose/d, the effect on fasting triacylglycerol depended on whether sucrose or starch was being exchanged with fructose, and the effect was dose-dependent but was less with increasing duration of treatment. Different health types and sources of bias were examined; they showed no significant departure from a general trend. CONCLUSIONS The meta-analysis shows that fructose intakes from 0 to >or=90 g/d have a beneficial effect on HbA(1c). Significant effects on postprandial triacylglycerols are not evident unless >50 g fructose/d is consumed, and no significant effects are seen for fasting triacylglycerol or body weight with intakes of
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Accuracy of the Atwater factors and related food energy conversion factors with low-fat, high-fiber diets when energy intake is reduced spontaneously.
Zou, ML, Moughan, PJ, Awati, A, Livesey, G
The American journal of clinical nutrition. 2007;(6):1649-56
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BACKGROUND Systems to calculate metabolizable energy (ME) in foods and diets are often based on Atwater factors. The accuracy of these factors with low-fat diets high in fiber is unknown when food intake is reduced spontaneously. OBJECTIVE The objective was to evaluate the accuracy of Atwater factors and other systems for calculating ME available from low-fat, high-fiber diets when food intake was reduced spontaneously. DESIGN The ME contents of a high-fat, low-fiber diet and 2 low-fat diets, one high in fruit and vegetable fiber and the other high in cereal fiber, were determined in a randomized parallel study in humans (n = 27) and compared with various factorial and empirical models for calculating ME. RESULTS Food intakes decreased with both the high fruit and vegetable fiber and cereal fiber diets. The difference between ME calculated by using Atwater and similar factors and determined ME values was up to 4% for the refined diet and up to 11% for the low-fat, high-fiber diets. Various factorial and empirical systems for calculating food energy failed to reflect the results of the direct determinations. CONCLUSION Atwater factors were inaccurate with low-fat, high-fiber diets. Although modified Atwater factors may be accurate under standardized conditions of zero-nitrogen and zero-energy balance, they overestimate energy availability from high-fiber fruit and vegetable and cereal diets when food intake is reduced spontaneously in addition to when intake is reduced voluntarily.