Diets high in glycemic index and glycemic load are associated with an increased risk of metabolic syndrome among Korean women

Dietary Glycemic Index, Glycemic Load, Sugar, and Fiber Intake in Association With Breast Cancer Risk: An Updated Meta-analysis

CONTEXT

Several prospective cohort studies have investigated the association between glycemic index (GI), glycemic load (GL), dietary sugar, and total dietary fiber intake, with female breast cancer (BC) risk and reported inconsistent results. In the last decade, several large epidemiological studies have investigated these associations, suggesting the need to revisit the current body of evidence.

OBJECTIVE

The aim of this study was to update a systematic review and meta-analysis conducted by Schlesinger et al in 2017 using recent scientific evidence published since 2015.

DATA SOURCES

Publications indexed in PubMed, Embase, and The Cochrane Library were retrieved from the inception of the database up to January 2024.

DATA EXTRACTION

Two reviewers independently extracted data and assessed each study's quality.

DATA ANALYSIS

A random-effects model was used to estimate summary risk ratios (RRs) and 95% CIs for a meta-analysis that included 33 publications, with 26 prospective cohort studies cumulatively enrolling 2 212 645 women, among whom 79 777 were diagnosed with incident BC.

RESULTS

Dietary GI and GL (highest vs lowest exposure intake) were both associated with 5% higher BC risk-RR (95% CI): 1.05 (1.01-1.09; P = .007) and 1.05 (0.97-1.13; P = .24), respectively. No clear associations were observed for sugar and total dietary fiber intake (highest vs lowest exposure intake)-RR (95% CI): 1.12 (0.95-1.11; P = .16) and 0.93 (0.86-1.00; P = .05), respectively. For the latter, the association was more pronounced among premenopausal women (RR: 0.78; 95% CI: 0.68-0.90; P = .0008).

CONCLUSION

This meta-analysis supports a significant positive association between high dietary GI intake and higher risk of BC and a significant inverse association between high dietary fiber intake and lower risk of BC. Interventions promoting a high-fiber and low-sugar diet may be useful components of BC-prevention strategies.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO registration no. CRD42023463143.

Associations between Dietary Patterns and Metabolic Syndrome: Findings of the Korean National Health and Nutrition Examination Survey

Metabolic syndrome (MetS) is a multifactorial cluster of metabolic disorders related to cardiovascular disease and type 2 diabetes mellitus. Diet and dietary patterns are significant factors in the development and management of MetS. The associations between dietary patterns (i.e., high-carbohydrate [HCHO], high-fat [HF], and high-protein [HP] diets) and the prevalence of MetS in Koreans were examined using data from the Korean National Health and Nutrition Examination Survey, collected between 2018 and 2020. The study included data from 9069 participants (3777 men and 5292 women). The percentage of participants with MetS was significantly higher in the HCHO diet group than in the normal diet group in women. Women with HCHO diet were positively associated with elevated blood pressure and triglyceride levels based on a comparison with the normal diet group (p = 0.032 and p = 0.005, respectively). Men with an HF diet were negatively associated with elevated fasting glucose levels based on a comparison with the normal diet group (p = 0.014). Our findings showed that HCHO intake was strongly associated with a higher risk of MetS, especially elevated blood pressure and triglyceride levels in women, and an HF diet was negatively associated with elevated fasting glucose levels in men. Further prospective studies of the impact of dietary carbohydrate, fat, and protein proportions on metabolic health are needed. The optimal types and proportions of these dietary components, as well as the underlying mechanisms through which suboptimal proportions can lead to MetS, should also be investigated.

Dietary glycemic index and glycemic load mediate the effect of CARTPT rs2239670 gene polymorphism on metabolic syndrome and metabolic risk factors among adults with obesity

INTRODUCTION

The importance of genetic and dietary factors in occurrence and progression of chronic diseases such as metabolic syndrome (MetS) has been established. However, complex interrelationships, including direct and indirect effects of these variables are yet to be clarified. So, our aim was to investigate the mediating role of glycemic indices in the relationship between CARTPT rs2239670 polymorphism, socio-demographic and psychological factors and metabolic risk factors and the presence of MetS in adults with obesity.

METHODS

In a cross-sectional study of 288 apparently healthy adults with obesity aged 20-50 years, dietary glycemic index (GI) and glycemic load (GL) were measured using a validated semi-quantitative food frequency questionnaire (FFQ). Biochemical parameters, blood pressure and anthropometric indicators were assayed by standard methods. Genotyping was carried out by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Structural equation modeling (SEM) was used in the statistical analysis.

RESULTS

CARTPT rs2239670 had a positive direct effect on MetS (B = 0.037 ± 0.022; P = 0.043) and, on the other hand, this variant was found to be indirectly associated with MetS presence through mediation of GI (B = 0.039 ± 0.017; P = 0.009). CARTPT was a significant predictor of both dietary GI and GL (B = 1.647 ± 0.080 and B = 3.339 ± 0.242, respectively). Additionally, glycemic indicators appeared to mediate the association of age and gender with LDL-C (B = 0.917 ± 0.332; P = 0.006) and HDL (B = 1.047 ± 0.484; P = 0.031), respectively. GI showed a positive relationship with LDL-C (P = 0.024) in men and similar relationships were found between GL and LDL-C (P = 0.050) and cholesterol (P = 0.022) levels in women.

CONCLUSION

The SEM findings suggest a hypothesis of the mediating effect of glycemic indices in the relationship between genetic susceptibility to obesity and MetS presence. Our findings need to be confirmed with large prospective studies.

Nutrition and the state of the intestinal microflora in the formation of the metabolic syndrome

The literature review presents the results of modern studies of the relationship between diet and intestinal microbiota in the regulation of metabolic disorders. Metabolic syndrome, which is a symptom complex that combines abdominal obesity, insulin resistance, hyperglycemia, dyslipidemia and arterial hypertension, remains an important problem, being a risk factor for cardiovascular, neurodegenerative, oncological diseases and the development of type 2 diabetes mellitus. Although the pathogenesis of the metabolic syndrome has not yet been fully elucidated, it is known that visceral obesity and its associated complications, such as dyslipidemia and increased levels of pro-inflammatory cytokines, play a central role. The article presents data on the impact of the consumption of certain food products, the inclusion of plant biologically active substances (flavonoids, polyphenols, etc.) in the diet, as well as the use of elimination diets with the exclusion of carbohydrates or fats from the diet, on reducing the risk of cardiovascular accidents, levels of fasting glucose, total cholesterol, LDL, triglycerides, C-reactive protein, leptin, insulin, reduction in body weight and waist circumference, reduction in the level of circulating endotoxins and changes in the activity of immunocompetent cells. Data are presented on the possible influence of the intestinal microbiota in maintaining inflammation and the formation of degenerative changes in the body. The role of changes in the ratio of the levels of pathogenic microflora, bifidobacteria and lactobacilli in the formation of a pathological condition is shown.