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

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 (HbA 1c ). 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, 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 HbA 1c 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, I 2 =75%, P<0.001). Reductions occurred also in fasting glucose, LDL-C, non-HDL-C, apo B, triglycerides, body weight, BMI, and CRP (P<0.05), but not blood insulin, HDL-C, waist circumference, or blood pressure. A positive dose-response gradient was seen for the difference in GL and HbA 1c and for absolute dietary GI and SBP (P<0.05). The certainty of evidence was high for the reduction in HbA 1c 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, 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 .

Adherence to the Mediterranean Diet Is Associated with Better Metabolic Features in Youths with Type 1 Diabetes

“…A high HbA1c was mostly related to a high intake of sweets which are rich in sugars. This is consistent with previous data on the fact that apart from total carbohydrate daily content, source of carbohydrate intake, and, therefore, glycemic load/index, is associated with HbA1c levels [57][58][59][60]. Furthermore, we observed that a high TIR was associated with a high intake of fish.…”

Associations between Dietary Patterns and Cardiometabolic Risk Factors—A Longitudinal Analysis among High-Risk Individuals for Diabetes in Kerala, India

“…This may be due to the high cost and availability of Hb1Ac tests in Indian settings. In a recent systematic review of randomized control studies on the effect of low glycemic index (GI) or dietary patterns on glycemic control suggested that low GI foods or dietary patterns reduced HbA1c when compared with higher GI foods or dietary patterns [ 38 ]. The “rice-meat-refined wheat” pattern identified in the present study is characterized by rice and refined wheat (high GI) and meat (e.g., beef and poultry).…”

Effects of Spaghetti Differing in Soluble Fiber and Protein Content on Glycemic Responses in Humans: A Randomized Clinical Trial in Healthy Subjects

“…It has been shown that regular consumption of high GI foods is associated with increased chronic disease risk [ 3 , 10 , 11 ], whereas low to moderate GI foods are considered favorable to health [ 2 , 12 ]. Replacement of higher GI with lower GI foods seems to offer a moderate improvement in glycemic control [ 13 , 14 ]. In some cohort studies, the GL, but not the carbohydrate content, has been frequently linked to a reduced risk of type 2 diabetes [ 10 ].…”

“…In some cohort studies, the GL, but not the carbohydrate content, has been frequently linked to a reduced risk of type 2 diabetes [ 10 ]. It has been proposed that lowering the GL of consumed carbohydrates may lead to a significant reduction in hemoglobin A1C from −0.2% up to −0.5% [ 14 , 15 , 16 ]. It should be noted however that other factors, such as the inclusion of soluble dietary fiber, resistant starch and amylose, and inclusion of non-cereal ingredients (i.e., οat fiber, flaxseed, legume-based flours, protein) may influence the glycemic responses [ 3 , 6 , 17 , 18 , 19 , 20 ].…”