Dietary Glycemic Index and Load and the Risk of Type 2 Diabetes: A Systematic Review and Updated Meta-Analyses of Prospective Cohort Studies

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 now over a decade ago that a published meta-analysis used a predefined standard to identify valid studies. Considering valid studies only, and using random effects dose–response meta-analysis (DRM) while withdrawing spurious results (p < 0.05), we ascertained whether these relations would 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). The combined T2D–GI RR was 1.27 (1.15–1.40) (p < 0.001, n = 10 studies) per 10 units GI, while that for the 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 2000 kcal diet, respectively. In conclusion, among adults initially in good health, diets higher in GI or GL were robustly associated with incident T2D. Together with mechanistic and other data, this supports 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 GL are substantial food markers predicting the development of T2D worldwide, for persons of European ancestry and of East Asian ancestry.

Dietary Strategies for Metabolic Syndrome: A Comprehensive Review

“…Moreover, some effects on lipid profile were observed in individuals with high CH intake, such as elevated BP, triglycerides and LDL-c and reduced HDL-c levels [ 98 , 99 ]. The mechanisms underlying the health benefits observed in low-CH diets are the avoidance of the rapid absorption associated with some types of CH, such as glucose and refined grains, which leads to an increase in insulin resistance and insulin demand [ 53 , 54 ]. Therefore, in the case of T2DM, recent clinical guidelines do not recommend a specific CH distribution or restriction, and dietary individualization must be prioritized in the treatment and management of this condition [ 49 ].…”

The role of bread in the UK diet: An update

“…For example, adding a fat spread to bread reduces the GI, but also increases the fat and calorie content. Data have been presented which suggest that diets higher in GI and GL are associated with incident type 2 diabetes (Livesey et al 2019). However, higher and lower GI/GL diets will, in most cases, differ in many ways other than the carbohydrate fraction.…”

“…Prevalence of type 2 diabetes is likely to increase in the future as the number of people with overweight and obesity has increased in recent years. Evidence provided by observational studies indicates that a diet higher in GI or GL is associated with a greater risk of type 2 diabetes (SACN 2015; Livesey et al 2019), and some research has shown that choosing low GI foods as part of a balanced diet can help to control blood glucose levels in people with type 2 diabetes. Therefore, healthier ‘slow release’ or low GI foods that are high in fibre ( e.g.…”

The Relationship between Glycemic Index and Health

“…In nutrition epidemiology, Livesey and members of the International Carbohydrate Quality Consortium undertook a dose response meta-analysis of prospective cohort studies on the relationship between GI and glycemic load (GL) and risk of type 2 diabetes [5]. They found that GI was robustly associated with incident type 2 diabetes, with the risk increasing by almost 90% when comparing the lowest to the highest exposure worldwide, i.e., overall dietary GI of 48 vs 76.…”