Carbohydrate quality, glycemic index, glycemic load andcardiometabolic risks in the US, Europe and Asia: A doseeresponse meta-analysis
Dale S. Hardy,Jane T. Garvin,Hongyan Xu,et al.
https://doi.org/10.1016/j.numecd.2019.12.050
0939-4753/ª 2020 The Italian Diabetes Society, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition and the Department of ClinicalMedicine and Surgery, Federico II University. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).
Abstract
Background and aims: Despite the proven evidence of high glycemic index (GI) and glycemic load (GL) diets to increase cardiometabolic risks, knowledge about the meta-evidence for carbohydrate quality within world geographic regions is limited. We conducted a meta-analysis to synthesize the evidence of GI/GL studies and carbohydrate quality, gathering additional exposures for carbohydrate, high glycemic carbohydrate, total dietary fiber, and cereal fiber and risks for type 2 diabetes (T2DM), coronary heart disease (CHD), stroke, and mortality, grouped into the US, Europe,and Asia. Secondary aims examined cardiometabolic risks in overweight/obese individuals, by sex,and doseeresponse dietary variable trends.
Methods and results: 40-prospective observational studies from 4-Medline bibliographical databases(Ovid, PubMed, EBSCOhost, CINAHL) were search up to November 2019. Random-effects hazard ratios (HR) and 95% confidenceintervals (CI) for highest vs. lowest categories and continuous form combined were reported. Heterogeneity (I2>50%) was frequent in US GI/GL studies due to differing study characteristics. Increased risks ((HRGI,T2DM,US=1.14;CI:1.06,1.21),HRGL,T2DM,US=1.02 (1.01, 1.03)),HRGI,T2DM,Asia=1.25;1.02,1.53), and HRGL,T2DM,Asia=1.37(1.17,1.60)) were associated with cardiometabolic diseases. GI/GL in overweight/obese females had the strongest magnitude of risks in US-and Asian studies. Total dietary fiber (HRT2DM,US=0.92;0.88,0.96) and cereal fiber(HRT2DM,US=0.83;0.77,0.90) decreased risk of developing T2DM. Among females, we found protective doseeresponse risks for total dietary fiber (HR5g-total-dietary-fiber,T2DM,US=0.94;0.92,0.97), but cereal fiber showed better ability to lower T2DM risk (HR5g-cereal-fiber,T2DM,US=0.67;0.60,0.74). Total dietary-and cereal fibers' dose-response effects were nullified by GL, but not so for cereal fiber with GI.
Conclusions: Overweight/obese females could shift their carbohydrate intake for higher cerealfiber to decrease T2DM risk, but higher GL may cancel-out this effect.