Dietary glycemic index and glycemic load are associated with high-density-lipoprotein cholesterol at baseline but not with increased risk of diabetes in the Whitehall II study

Glycemic index, glycemic load, dietary insulin index, and dietary insulin load in relation to cardiometabolic risk factors among participants with atherosclerosis: a cross-sectional study

BACKGROUND

We examined the cross-sectional associations of dietary Glycemic Index (GI), Glycemic Load (GL), Dietary Insulin Index (DII), and Dietary Insulin Load (DIL) with cardiovascular disease (CVD) factors in subjects with atherosclerosis.

METHODS

The present cross-sectional study was conducted on subjects with atherosclerosis. Regular dietary intake was assessed using a 168-item semi-quantitative food frequency questionnaire (FFQ) and GI, GL, DIL, and DII were also calculated. Odds Ratio (OR) and 95% Confidence Intervals (CIs) were estimated for general and central obesity according to the GI, GL, DII, and DIL.

RESULTS

According to the continuous score of GL, there was a significant positive association between GL and central obesity for women in all models. Regarding the association between DIL score and biochemical variables, there was a significant positive association between Na and Aspartate transaminase (AST) with DII. Moreover, there was a significant positive association between LDL-c(p = 0.03) and AST (p = 0.04)with DIL score in all 3 models.

CONCLUSION

In this study, GL was associated with greater odds of central obesity in women, but not in men. Neither dietary DII nor DIL was associated with BMI and central obesity. GI, GL, DII, and DIL were significantly associated with some CVD risk biomarkers in subjects with atherosclerosis.

Associations between Conventional and Emerging Indicators of Dietary Carbohydrate Quality and New-Onset Type 2 Diabetes Mellitus in Chinese Adults

Dietary glycemic index (GI), carbohydrate to fiber ratio (CF) and carbohydrate quality index (CQI) are conventional and emerging indicators for carbohydrate quality. We aimed to investigate the associations between these indicators and new-onset type 2 diabetes mellitus (T2DM) risk among Chinese adults. This prospective cohort study included 14,590 adults from the China Health and Nutrition Survey without cardiometabolic diseases at baseline. The associations between dietary GI, CF and CQI and T2DM risk were assessed using Cox proportional hazard regression analysis and dose-response relationships were explored using restricted cubic spline and threshold analysis. After a mean follow-up duration of 10 years, a total of 1053 new-onset T2DM cases occurred. There were U-shaped associations between dietary GI and CF and T2DM risk (both P-nonlinear < 0.0001), and T2DM risk was lowest when dietary GI was 72.85 (71.40, 74.05) and CF was 20.55 (17.92, 21.91), respectively (both P-log likelihood ratio < 0.0001). Inverse associations between CQI and T2DM risk specifically existed in participants < 60 y or attended middle school or above (both P-trend < 0.05). These findings indicated that moderate dietary GI and CF range and a higher dietary CQI score may be suggested for T2DM prevention in Chinese adults.

Dietary glycemic load and its association with glucose metabolism and lipid profile in young adults

BACKGROUND AND AIM

To evaluate the association of Glycemic Load (GL) with glucose metabolism and blood lipids among young adults.

METHODS AND RESULTS

This study included 1538 participants (51% females), evaluated at 21 years of age as part of the EPITeen cohort. The GL of each individual was obtained from the assessment of their dietary intake by using a 86-item semi-quantitative food frequency questionnaire. The evaluation included anthropometric measurements and a fasting blood sample was used to measure glucose, insulin, triglycerides, total cholesterol, high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C). Insulin resistance was calculated based on the homeostasis model method (HOMA-IR). The association between the GL and the biochemical parameters was evaluated by linear regression models using β and 95% confidence intervals (95% CI), stratified by sex and adjusted for body mass index (BMI), energy and fiber intake, and self-perceived social class. No association was found between GL and the glucose metabolism parameters after adjustment. Regarding blood lipids, a positive association was found with LDL-C (β = 1.507, 95% CI 0.454; 2.561 for females; β = 0.216, 95% CI -0.587; 1.020 for males) and a negative association with HDL-C (β = -0.647, 95% CI -1.112; -0.181 for females; β = -0.131, 95% CI -0.422; 0.160 for males).

CONCLUSIONS

Our results suggest that, in healthy young subjects, a high GL diet may have a negative impact on lipid profile.

Macronutrient Determinants of Obesity, Insulin Resistance and Metabolic Health

Obesity caused by the overconsumption of calories has increased to epidemic proportions. Insulin resistance is often associated with an increased adiposity and is a precipitating factor in the development of cardiovascular disease, type 2 diabetes, and altered metabolic health. Of the various factors contributing to metabolic impairments, nutrition is the major modifiable factor that can be targeted to counter the rising prevalence of obesity and metabolic diseases. However, the macronutrient composition of a nutritionally balanced "healthy diet" are unclear, and so far, no tested dietary intervention has been successful in achieving long-term compliance and reductions in body weight and associated beneficial health outcomes. In the current review, we briefly describe the role of the three major macronutrients, carbohydrates, fats, and proteins, and their role in metabolic health, and provide mechanistic insights. We also discuss how an integrated multi-dimensional approach to nutritional science could help in reconciling apparently conflicting findings.

Associations between Dietary Glycemic Index and Glycemic Load Values and Cardiometabolic Risk Factors in Adults: Findings from the China Health and Nutrition Survey

Studies investigating the associations between dietary glycemic index (GI) and glycemic load (GL) values and cardiometabolic risk factors (CMRF) among Chinese populations are strikingly limited. To assess the associations between dietary GI and GL values and CMRF, including dyslipidemia, hyperglycemia, and hyperuricemia in Chinese adults, we extracted data of 7886 apparently healthy adults from the 2009 wave of the China Health and Nutrition Survey. Dietary GI and GL values were calculated using data collected from three consecutive 24 h dietary recalls. Fasting lipid, glucose, and uric acid concentrations were measured and CMRF were defined on the basis of established criteria. There were no significant associations between dietary GI values and CMRF, and analyzing the data by age, sex, body mass index (BMI), and region did not alter these results. Dietary GL values were positively associated with prevalence of hyperuricemia in all participants (Q4 compared with Q1: odds ratio (OR) = 1.46; 95% CI: 1.14, 1.87; p-trend = 0.0030) and prevalence of hypercholesterolemia in participants ≥ 60 years old (Q5 compared with Q1: OR = 1.72; 95% CI: 1.11, 2.68; p-trend < 0.0010). Higher dietary GL but not GI values were associated with increased prevalence of hyperuricemia in apparently healthy Chinese adults and hypercholesterolemia in older Chinese adults. Further studies are required to confirm the public health implication of these findings.

Association between Dietary Glycaemic Index and Glycaemic Load and Adiposity Indices in Polycystic Ovary Syndrome

Objective: Obesity is a key contributor to metabolic and reproductive outcomes in polycystic ovary syndrome (PCOS). The role of the dietary glycemic index (GI) and load (GL), and adiposity has been debated and studies on PCOS are scarce. We aimed to compare the dietary GI and GL and several anthropometric measurements in PCOS and control women. The association between dietary GI and GL and adiposity indices was examined in this cross-sectional study.Methods and materials: A study population consisted of 65 previously diagnosed with PCOS and 65 healthy women. All participants underwent detailed anthropometric, dietary and physical activity evaluation and categorized based on GI and GL tertiles.Results: When dietary GL was adjusted for age, physical activity level (PAL), and duration of diagnosis, there was a statistically significant inverse association between dietary GL and waist/hip ratio (WHR) (OR: 0.136; 95% CI: 0.021-0.874; p = 0.036) in women with PCOS. Both dietary GI (OR: 8.869; 95% CI: 1.194-65.910; p = 0.033 for tertile 2 in adjustment model) and GL (OR: 7.200; 95% CI: 1.635-31.712; p = 0.009 for tertile 3 in crude model; OR: 5.801; 95% CI: 1.242-27.096; p = 0.025 for tertile 3 in adjustment model) positively associated with WHR in healthy subjects. Also, positive association was observed between dietary GI and waist/height ratio (WHtR) (OR: 0.229; 95% CI: 0.063-0.826; p = 0.024 for tertile 2; OR: 0.277; 95% CI: 0.078-0.988; p = 0.048 for tertile 3) in healthy controls, however after adjustment for age and PAL, statistical significance was lost (OR: 1.051; 95% CI: 0.152-7.261; p = 0.959 for tertile 2; OR: 1.522; 95% CI: 0.225-10.297; p = 0.667 for tertile 3).Conclusion: The results of this study consistent with the literature that PCOS is associated with increased adiposity indices. There was no association between dietary GI/GL and BMI, WC, WHtR, and ABSI but dietary GL was inversely associated WHR in PCOS patients.

The association between glycemic index, glycemic load, and metabolic syndrome: a systematic review and dose-response meta-analysis of observational studies

PURPOSE

The association of glycemic index (GI) and glycemic load (GL) with metabolic syndrome (MetS) is controversial. Therefore, we conducted this first systematic review and dose-response meta-analysis of observational studies to quantify these associations.

METHODS

We searched PubMed, EMBASE, Web of Science, and the Cochrane Library for relevant studies up to 1 April 2019. Summary odds ratios (OR) and 95% confidence intervals (CI) were calculated by a random-effects model. This study was registered with PROSPERO (CRD42019131788).

RESULTS

We included eight high-quality (n = 5) or medium-quality (n = 3) cross-sectional studies in the final meta-analysis, comprising 6058 MetS events and 28,998 participants. The summary ORs of MetS for the highest versus lowest categories were 1.23 (95% CI 1.10-1.38, I² = 0, tau² = 0, n = 5) for dietary GI, 1.06 (95% CI 0.89-1.25, I² = 36.2%, tau² = 0.0151, n = 6) for dietary GL. The summary OR was 1.12 (95% CI 1.00-1.26, I² = 0, tau² = 0, n = 3) per 5 GI units, 0.96 (95% CI 0.83-1.10, I² = 33.4%, tau² = 0.0059, n = 2) per 20 GL units.

CONCLUSIONS

Dietary GI was positively associated with the prevalence of MetS. However, no significant association was found between dietary GL and the prevalence of MetS. Further studies with prospective design are needed to establish potential causal relationship between dietary GI and the MetS.

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

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 glycemic index and glycemic load in relation to general obesity and central adiposity among adults

BACKGROUND & AIMS

Although the association between dietary Glycemic Index (GI), Glycemic Load (GL) and general/abdominal obesity has extensively been examined, limited data are available in this regard in developing countries. The aim of this study was to examine the association between dietary GI and GL with general and abdominal obesity.

METHODS

This cross-sectional study was conducted among adults in Isfahan, Iran. Dietary GI and GL were assessed using a validated dish-based 106-item semi-quantitative food frequency questionnaire (DS-FFQ). Data regarding height, weight and waist circumference were collected using a self-reported questionnaire. Overweight or obesity was defined as body mass index ≥25 kg/m², and abdominal obesity was defined as waist circumference ≥80 cm for women and ≥94 cm for men.

RESULTS

There was no significant association between dietary GI and GL and general obesity. After adjustment for potential confounders, participants in the highest quintile of dietary GI had a higher chance for abdominal obesity (OR: 1.29; 95% CI: 1.01-1.64), compared with those in the lowest quintile. No significant association was observed between dietary GL and abdominal obesity. After adjustment for potential confounders, women in the top quintile of dietary GI had higher chance for abdominal obesity compared with those in the bottom quintile (OR: 1.48, 95% CI: 1.02-2.15). No significant association was found between dietary GI and abdominal obesity among men. We failed to find any significant association between dietary GI and general obesity in either gender [Comparing top vs. bottom quintiles, for men: OR: 0.97; 95% CI: 0.74-1.29 and for women: OR: 1.01; 95% CI: 0.75-1.40]. No significant association was found between dietary GL and general [for men: OR: 1.13; 95% CI: 0.85-1.49 and for women: OR: 1.01; 95% CI: 0.76-1.35], as well as abdominal obesity [for men: OR: 1.21; 95% CI: 0.88-1.67 and for women: OR: 1.25; 95% CI: 0.88-1.77].

CONCLUSIONS

We found a significant positive association between dietary GI and abdominal obesity. When we conducted analyses stratified by gender, we also observed such association in women, but not in men. No other significant associations were observed between dietary GI and GL with general or abdominal obesity.

Association between End-Stage Renal Disease and Incident Diabetes Mellitus-A Nationwide Population-Based Cohort Study

Background: Glucose is one of the constituents in hemodialysates and peritoneal dialysates. How the dialysis associates with the incident diabetes mellitus (DM) remains to be assessed. Methods: The claim data of end-stage renal disease (ESRD) patients who initiated dialysis from and a cohort of matched non-dialysis individuals from 2000 to 2013 were retrieved from the Taiwan National Health Insurance Research Database to examine the risk of incident DM among patients on hemodialysis (HD) and peritoneal dialysis (PD). Predictors of incident DM were determined for HD and PD patients using Fine and Gray models to treat death as a competing event, respectively. Results: A total of 2228 patients on dialysis (2092 HD and 136 PD) and 8912 non-dialysis individuals were the study population. The PD and HD patients had 12 and 97 new-onset of DM (incidence rates of 15.98 and 8.69 per 1000 patient-years, respectively), while the comparison cohort had 869 DM events with the incidence rate of 15.88 per 1000 patient-years. The multivariable-adjusted Cox models of Fine and Gray method showed that the dialysis cohort was associated with an adjusted hazard ratio (HR) of 0.49 (95% CI 0.39–0.61, p value < 0.0001) for incident DM compared with the comparison cohort. The adjusted HR of incident DM was 0.46 (95% CI 0.37–0.58, p value < 0.0001) for HD and 0.84 (95% CI 0.47–1.51, p value = 0.56) for PD. Conclusions: ESRD patients were associated with a lower risk of incident DM. HD was associated with a lower risk of incident DM, whereas PD was not.

Relevance of the Glycemic Index and Glycemic Load for Body Weight, Diabetes, and Cardiovascular Disease

Despite initial enthusiasm, the relationship between glycemic index (GI) and glycemic response (GR) and disease prevention remains unclear. This review examines evidence from randomized, controlled trials and observational studies in humans for short-term (e.g., satiety) and long-term (e.g., weight, cardiovascular disease, and type 2 diabetes) health effects associated with different types of GI diets. A systematic PubMed search was conducted of studies published between 2006 and 2018 with key words glycemic index, glycemic load, diabetes, cardiovascular disease, body weight, satiety, and obesity. Criteria for inclusion for observational studies and randomized intervention studies were set. The search yielded 445 articles, of which 73 met inclusion criteria. Results suggest an equivocal relationship between GI/GR and disease outcome. The strongest intervention studies typically find little relationship among GI/GR and physiological measures of disease risk. Even for observational studies, the relationship between GI/GR and disease outcomes is limited. Thus, it is unlikely that the GI of a food or diet is linked to disease risk or health outcomes. Other measures of dietary quality, such as fiber or whole grains may be more likely to predict health outcomes. Interest in food patterns as predictors of health benefits may be more fruitful for research to inform dietary guidance.

A greater glycemic load reduction was associated with a lower diabetes risk in pre-diabetic patients who consume a high glycemic load diet

Few prospective studies evaluating the association between dietary glycemic load (GL) and diabetes have accounted for changes in GL. However, the diet of patients could be modified in response to an awareness of pre-diabetes. The aim of this study was to examine the longitudinal associations between changes in GL and the incidence of diabetes among pre-diabetic patients. We hypothesized that subjects with low and high baseline GL would show different correlations with diabetes. A total of 493 pre-diabetic patients (142 men and 351 women) between 40 and 79 years of age were included in this study. Dietary records and oral glucose tolerance tests were conducted every year. The participants were divided into low- and high-GL groups based on baseline GL. During a median 4 years of follow-up, 108 incident cases of diabetes were identified. Among participants with a high baseline GL, the incidence of diabetes increased with decreasing GL reduction, and the multivariate-adjusted HR (95% CI) was 2.34 (1.27-4.29) when comparing the lowest to the highest tertiles; however, among those with a low baseline GL, no significant association was observed. Regardless of baseline GL status, the incidence of diabetes was higher in individuals with a high follow-up GL than in those with a low follow-up GL, and the multivariate-adjusted HR (95% CI) was 1.64 (1.09-2.45). In conclusion, a greater GL reduction was associated with a lower diabetes risk in pre-diabetic patients with a high dietary GL. In patients with pre-diabetes and a low dietary GL, further reductions in GL did not show any additional effects.

Sugar intake from sweet food and beverages, common mental disorder and depression: prospective findings from the Whitehall II study

Intake of sweet food, beverages and added sugars has been linked with depressive symptoms in several populations. Aim of this study was to investigate systematically cross-sectional and prospective associations between sweet food/beverage intake, common mental disorder (CMD) and depression and to examine the role of reverse causation (influence of mood on intake) as potential explanation for the observed linkage. We analysed repeated measures (23,245 person-observations) from the Whitehall II study using random effects regression. Diet was assessed using food frequency questionnaires, mood using validated questionnaires. Cross-sectional analyses showed positive associations. In prospective analyses, men in the highest tertile of sugar intake from sweet food/beverages had a 23% increased odds of incident CMD after 5 years (95% CI: 1.02, 1.48) independent of health behaviours, socio-demographic and diet-related factors, adiposity and other diseases. The odds of recurrent depression were increased in the highest tertile for both sexes, but not statistically significant when diet-related factors were included in the model (OR 1.47; 95% CI: 0.98, 2.22). Neither CMD nor depression predicted intake changes. Our research confirms an adverse effect of sugar intake from sweet food/beverage on long-term psychological health and suggests that lower intake of sugar may be associated with better psychological health.

Elevated C-reactive protein, interleukin 6, tumor necrosis factor alpha and glycemic load associated with type 2 diabetes mellitus in rural Thais: a cross-sectional study

BACKGROUND

The elevated levels of inflammatory markers, including C-reactive protein (CRP), tumor necrosis factor alpha (TNF-α), and interleukin 6 (IL6) are supposed to be associated with type 2 diabetes mellitus (T2DM). Frequent high glycemic load (GL) consumption, central obesity, and a lack of physical activity are considered to be T2DM risk factors. This study aimed to determine the difference of these inflammatory markers as well as GL in individuals with versus those without T2DM in rural Thais.

METHODS

A total of 296 participants aged 35-66 living in Sung Noen District, Nakhon Ratchasima Province, Thailand, were recruited. Blood was collected to evaluate blood glucose levels, lipid profiles, and inflammatory markers. A Semi-food frequency questionnaire was utilized to assess GL followed by socioeconomic and anthropometric assessment. Statistical analysis was subsequently performed.

RESULTS

Elevated CRP and IL6 levels were associated with increased risk of developing T2DM [OR (95% CI): 7.51 (2.11, 26.74) and 4.95 (1.28, 19.11)], respectively. There was a trend towards increased risk of T2DM with elevated TNF-α levels [OR (95% CI): 1.56 (0.39, 6.14)]. GL correlated significantly with fasting blood glucose (r = 0.289, P = 0.016), suggesting that it is involved in T2DM in this study group.

CONCLUSION

In this study, CRP, IL6, and TNF-α associated with T2DM. Our findings suggested that these inflammatory markers, especially CRP, may initiate T2DM.

Association of lower body mass index with increased glycemic variability in patients with newly diagnosed type 2 diabetes: a cross-sectional study in China

Previous studies have indicated that the pathogenesis of diabetes differs between obese and lean patients. We investigated whether newly diagnosed Chinese diabetic patients with different body mass indices (BMIs) have different glycemic variability, and we assessed the relationship between BMI and glycemic variability. This was a cross-sectional study that included 169 newly diagnosed and drug-naïve type 2 diabetic patients (mean age, 51.33 ± 9.83 years; 110 men). The clinical factors and results of the 75-g oral glucose tolerance test were all recorded. Glycemic variability was assessed using continuous glucose monitoring. Compared with overweight or obese patients (BMI ≥ 24 kg/m2), underweight or normal-weight patients (BMI < 24 kg/m2) had higher levels of blood glucose fluctuation parameters, particularly in terms of mean amplitude of glycemic excursion (MAGE 6.64 ± 2.38 vs. 5.67 ± 2.05; P = 0.007) and postprandial glucose excursions (PPGEs) (PPGE at breakfast, 7.72 ± 2.79 vs. 6.79 ± 2.40, P = 0.028; PPGE at lunch, 5.53 ± 2.70 vs. 5.07 ± 2.40, P = 0.285; PPGE at dinner, 5.96 ± 2.24 vs. 4.87 ± 2.50, P = 0.008). BMI was negatively correlated with glycemic variability (r = −0.243, P = 0.002). On multiple linear regression analyses, BMI (β = −0.231, P = 0.013) and Insulin Secretion Sensitivity Index-2 (β = −0.204, P = 0.048) were two independent predictors of glycemic variability. In conclusion, lower BMI was associated with increased glycemic variability, characterized by elevated PPGEs, in newly diagnosed Chinese type 2 diabetic patients.

Comparison of Dietary Intake between Polycystic Ovary Syndrome Women and Controls

Polycystic Ovary syndrome (PCOS) is a complicated endocrinopathy affecting women in reproductive age. The crucial role of obesity and insulin resistance in progression of metabolic and cardiovascular features of PCOS has been confirmed. Although it has been suggested that there is a possible association between dietary pattern and risk of PCOS, few studies investigating the diet composition of PCOS women. The aim of this study was to compare the dietary intakes between women with polycystic ovary syndrome (PCOS) and eumenorrheic non hirsute women. This was a case control study of 142 women with PCOS and 140 eumenorrheic non hirsute healthy age and BMI matched controls. We compared the dietary intakes of our study group using a validated food frequency questionnaire (FFQ), using T-test or Mann-Whitney to compare the means of two groups. One way Anova was used to compare the tertiles of GI and GL in each group and a two way ANOVA was used to compare between tertiles of GI-GL and groups. The results demonstrated that energy and macronutrient intakes in PCOS women compared to controls were similar. PCOS group consumed more food items with high glycemic index (p=0.042) and less legumes (P=0.026) and vegetables (p=0.037) than controls. Both groups in the highest tertile of glycemic load (GL) had higher body mass index and waist circumference. Considering the results of this study, it was concluded that PCOS women had a dietary pattern that was characterized by a higher consumption of high GI food items and lower legumes and vegetables.

The effect of dietary changes on distinct components of the metabolic syndrome in a young Sri Lankan population at high risk of CVD

South Asian populations are predisposed to early onset of the metabolic syndrome. Lifestyle intervention programmes have demonstrated a reduction in the metabolic syndrome and CVD risk; however, the most effective components of the multi-faceted lifestyle interventions are unknown. We studied 2637 Sri Lankan males (n 1237) and females (n 1380), with a mean BMI of 23·9 (sd 4·2) kg/m2, aged 22·5 (sd 10·0) years, who had participated in a 5-year lifestyle-modification programme to examine the effect of dietary changes on distinct components of the metabolic syndrome. The dietary intervention comprised advice to replace polished starches with unpolished starches, high-fat meat and dairy products with low-fat products and high-sugar beverages and snacks with low-sugar varieties. For the purposes of this analysis, data from the control and intensive lifestyle groups were combined. Anthropometric and biochemical data were recorded, and a FFQ was completed annually. Multiple regression was used to determine the effect of the dietary changes on distinct components of the metabolic syndrome. The ratio unpolished:polished rice was inversely related to change in fasting glucose (β=-0·084, P=0·007) and TAG (β=-0·084, P=0·005) and positively associated with change in HDL-cholesterol (β=0·066, P=0·031) at the 5-year follow-up after controlling for relevant confounders. Red meat intake was positively associated with fasting glucose concentrations (β=0·05, P=0·017), whereas low-fat (β=-0·046, P=0·018) but not high-fat dairy products (β=0·003, P=0·853) was inversely related to glucose tolerance at the follow-up visit. Replacement of polished with unpolished rice may be a particularly effective dietary advice in this and similar populations.

Effects of the intake of Undaria pinnatifida (Wakame) and its sporophylls (Mekabu) on postprandial glucose and insulin metabolism

Long-term suppression of postprandial glucose concentration is an important dietary strategy for the prevention and treatment of type 2 diabetes. Because previous reports have suggested that seaweed may exert anti-diabetic effects in animals, the effects of Wakame or Mekabu intake with 200 g white rice, 50 g boiled soybeans, 60 g potatoes, and 40 g broccoli on postprandial glucose, insulin and free fatty acid levels were investigated in healthy subjects. Plasma glucose levels at 30 min and glucose area under the curve (AUC) at 0-30 min after the Mekabu meal were significantly lower than that after the control meal. Plasma glucose and glucose AUC were not different between the Wakame and control meals. Postprandial serum insulin and its AUC and free fatty acid concentration were not different among the three meals. In addition, fullness, satisfaction, and wellness scores were not different among the three meals. Thus, consumption of 70 g Mekabu with a white rice-based breakfast reduces postprandial glucose concentration.

Glycemic load and coronary heart disease in a Mediterranean population: the EPIC Greek cohort study

BACKGROUND AND AIMS

High glycemic load (GL) has been associated with increased coronary heart disease (CHD) risk. We evaluated whether preference of low-GL foods conveys incremental benefits with respect to CHD, especially to people adhering to the traditional Mediterranean diet (MD).

METHODS AND RESULTS

We analyzed data from the Greek European Prospective Investigation into Cancer and Nutrition, including 20,275 participants free of cardiovascular diseases, cancer, or diabetes at baseline and without incident diabetes. Subjects completed a validated, semi-quantitative food frequency questionnaire at enrollment. We calculated a 10-point MD adherence score and the dietary GL, and estimated hazard ratios (HRs) for CHD incidence and mortality through Cox proportional hazard regression. After a median follow-up of 10.4 years, 417 participants developed CHD, and 162 died from the disease. A significant positive association of GL with CHD incidence emerged (HR for the highest versus the lowest tertile = 1.41, 95% confidence interval, CI: 1.05-1.90). HRs for CHD mortality exceeded unity but were not statistically significant. The association with GL was stronger among subjects with higher body mass index. High adherence to MD with low/moderate GL was associated with lower risk of CHD incidence (HR = 0.61, CI: 0.39-0.95) and mortality (HR = 0.47, 95% CI: 0.23-96).

CONCLUSION

High dietary GL increases the risk of CHD. Compared to a high GL diet with suboptimal adherence to the traditional Mediterranean pattern, a low/moderate GL diet that also conforms to the traditional MD principles could lead to a 40% reduced risk for CHD, and over 50% reduced risk for death from CHD.

Nutrigerontology: why we need a new scientific discipline to develop diets and guidelines to reduce the risk of aging-related diseases

Many diets and nutritional advice are circulating, often based on short- or medium-term clinical trials and primary outcomes, like changes in LDL cholesterol or weight. It remains difficult to assess which dietary interventions can be effective in the long term to reduce the risk of aging-related disease and increase the (healthy) lifespan. At the same time, the scientific discipline that studies the aging process has identified some important nutrient-sensing pathways that modulate the aging process, such as the mTOR and the insulin/insulin-like growth factor signaling pathway. A thorough understanding of the aging process can help assessing the efficacy of dietary interventions aimed at reducing the risk of aging-related diseases. To come to these insights, a synthesis of biogerontological, nutritional, and medical knowledge is needed, which can be framed in a new discipline called 'nutrigerontology'.

Higher breakfast glycaemic load is associated with increased metabolic syndrome risk, including lower HDL-cholesterol concentrations and increased TAG concentrations, in adolescent girls

Almost all previous studies examining the associations between glycaemic load (GL) and metabolic syndrome risk have used a daily GL value. The daily value does not distinguish between peaks of GL intake over the day, which may be more closely associated with the risk of the metabolic syndrome. The aim of the present study was to investigate the cross-sectional associations between daily and mealtime measures of GL and metabolic syndrome risk, including metabolic syndrome components, in adolescents. Adolescents participating in the 14-year follow-up of the Western Australian Pregnancy Cohort (Raine) Study completed 3 d food records and metabolic assessments. Breakfast GL, lunch GL, dinner GL and a score representing meal GL peaks over the day were determined in 516 adolescents. Logistic regression models were used to investigate whether GL variables were independent predictors of the metabolic syndrome in this population-based cohort (3·5 % prevalence of the metabolic syndrome). Breakfast GL was found to be predictive of the metabolic syndrome in girls (OR 1·15, 95 % CI 1·04, 1·27; P <0·01), but not in boys. Other meal GL values and daily GL were found to be not significant predictors of the metabolic syndrome. When breakfast GL was examined in relation to each of the components of the metabolic syndrome in girls, it was found to be negatively associated with fasting HDL-cholesterol concentrations (P= 0·037; β = − 0·004; 95 % CI − 0·008, − 0·002) and positively associated with fasting TAG concentrations (P= 0·008; exp(β) = 1·002; 95 % CI 1·001, 1·004). The results of the present study suggest that there may be an association between breakfast composition and metabolic syndrome components in adolescent girls. These findings support further investigation into including lower-GL foods as part of a healthy breakfast in adolescence, particularly for girls.

Glycemic index, glycemic load, and risk of type 2 diabetes: results from 3 large US cohorts and an updated meta-analysis

BACKGROUND

Epidemiologic evidence for the relation between carbohydrate quality and risk of type 2 diabetes (T2D) has been mixed.

OBJECTIVE

We prospectively examined the association of dietary glycemic index (GI) and glycemic load (GL) with T2D risk.

DESIGN

We prospectively followed 74,248 women from the Nurses' Health Study (1984-2008), 90,411 women from the Nurses' Health Study II (1991-2009), and 40,498 men from the Health Professionals Follow-Up Study (1986-2008) who were free of diabetes, cardiovascular disease, and cancer at baseline. Diet was assessed by using a validated questionnaire and updated every 4 y. We also conducted an updated meta-analysis, including results from our 3 cohorts and other studies.

RESULTS

During 3,800,618 person-years of follow-up, we documented 15,027 cases of incident T2D. In pooled multivariable analyses, those in the highest quintile of energy-adjusted GI had a 33% higher risk (95% CI: 26%, 41%) of T2D than those in the lowest quintile. Participants in the highest quintile of energy-adjusted GL had a 10% higher risk (95% CI: 2%, 18%) of T2D. Participants who consumed a combination diet that was high in GI or GL and low in cereal fiber had an ~50% higher risk of T2D. In the updated meta-analysis, the summary RRs (95% CIs) comparing the highest with the lowest categories of GI and GL were 1.19 (1.14, 1.24) and 1.13 (1.08, 1.17), respectively.

CONCLUSION

The updated analyses from our 3 cohorts and meta-analyses provide further evidence that higher dietary GI and GL are associated with increased risk of T2D.

Glycemic index, glycemic load and childhood obesity: A systematic review

Background:

Several evidences have been reported so far in terms of the relationship between obesity and glycemic index and glycemic load in children. However, the number of review studies that have dealt with recent findings is quite low. The purpose of present study is to review the existing evidences in this regard.

Materials and Methods:

First of all, the phrases: “Glycaemic index”, “Glycaemic load”, “Glycemic index” OR “Glycemic load” accompanied by one of the words: “Adolescent”, “Young”, “Youth” “Children” OR “Child” were searched in texts of articles existing in ISI and PUBMED databases which were obtained out of 1001 articles. Among these, some articles, which reviewed the relationship of obesity with glycemic index and glycemic load, were selected. Finally, 20 articles were studied in current review study.

Results:

The majority of cross-sectional studies have found children's obesity directly linked with glycemic index and glycemic load; however, cohort studies found controversial results. Also, the intervention studies indicate the negative effect of glycemic index and glycemic load on obesity in children.

Conclusion:

Published evidences reported inconsistent results. It seems that existing studies are not sufficient and more studies are needed in this regard.

Dietary fiber intake and risk of type 2 diabetes: a dose-response analysis of prospective studies

Observational studies suggest an association between dietary fiber intake and risk of type 2 diabetes, but the results are inconclusive. We conducted a meta-analysis of prospective studies evaluating the associations of dietary fiber intake and risk of type 2 diabetes. Relevant studies were identified by searching EMBASE (from 1974 to April 2013) and PubMed (from 1966 to April 2013). The fixed or random-effect model was selected based on the homogeneity test among studies. In addition, a 2-stage random-effects dose-response meta-analysis was performed. We identified 17 prospective cohort studies of dietary fiber intake and risk of type 2 diabetes involving 19,033 cases and 488,293 participants. The combined RR (95 % CI) of type 2 diabetes for intake of total dietary fiber, cereal fiber, fruit fiber and insoluble fiber was 0.81 (0.73-0.90), 0.77 (0.69-0.85), 0.94 (0.88-0.99) and 0.75 (0.63-0.89), respectively. A nonlinear relationship was found of total dietary fiber intake with risk of type 2 diabetes (P for nonlinearity < 0.01), and the RRs (95 % CI) of type 2 diabetes were 0.98 (0.90-1.06), 0.97 (0.87-1.07), 0.89 (0.80-0.99), 0.76 (0.65-0.88), and 0.66 (0.53-0.82) for 15, 20, 25, 30, and 35 g/day. The departure from nonlinear relationship was not significant (P for nonlinearity = 0.72), and the risk of type 2 diabetes decreased by 6 % (RR 0.94, 95 % CI 0.93-0.96) for 2 g/day increment in cereal fiber intake. Findings from this meta-analysis indicate that the intakes of dietary fiber may be inversely associated with risk of type 2 diabetes.

Dietary glycemic index, glycemic load and incidence of type 2 diabetes in Japanese men and women: the Japan Public Health Center-based Prospective Study

Background

Japanese diets contain a relatively high amount of carbohydrates, and its high dietary glycemic index and glycemic load may raise the risk of diabetes in the Japanese population. The current study evaluated the associations between the dietary glycemic index, glycemic load, and the risk of type 2 diabetes in a population based cohort in Japan.

Methods

We observed 27,769 men and 36,864 women (45–75 y) who participated in the second survey of the Japan Public Health Center-based Prospective Study. The dietary glycemic index and glycemic load were estimated using a food-frequency questionnaire. The development of diabetes was reported in a questionnaire administered five years later, and the associations were analyzed using logistic regression after controlling for age, area, total energy intake, smoking status, family history of diabetes, physical activity, hypertension, BMI, alcohol intake, magnesium, calcium, dietary fiber and coffee intake, and occupation.

Results

The dietary glycemic load was positively associated with the risk of diabetes among women: the multivariable-adjusted odds ratio comparing the highest vs. the lowest quartile was 1.52 (95% CI, 1.13-2.04; P-trend = 0.01). The association was implied to be stronger among women with BMI < 25 than the women with BMI ≥ 25. The dietary glycemic index was positively associated with the risk of diabetes among men with a high intake of total fat: the multivariable-adjusted odds ratio comparing the highest vs. the lowest quartile was 1.46 (95% CI, 0.94-2.28; P-trend = 0.04). Among women with a high total fat intake, those in the first and second quartiles of the dietary glycemic index had a significant reduced risk of diabetes, compared with those in the first quartile who had a lower total fat level (multivariable-adjusted odds ratio = 0.59 with 95% CI, 0.37-0.94, and odds ratio = 0.63 with 95% CI, 0.40-0.998 respectively).

Conclusions

The population-based cohort study in Japan indicated that diets with a high dietary glycemic load increase the risk of type 2 diabetes among women. Total fat intake may modify the association between the dietary glycemic index and the risk of type 2 diabetes among men and women.

Glycemic index, glycemic load, carbohydrates, and type 2 diabetes: systematic review and dose-response meta-analysis of prospective studies

OBJECTIVE

Diets with high glycemic index (GI), with high glycemic load (GL), or high in all carbohydrates may predispose to higher blood glucose and insulin concentrations, glucose intolerance, and risk of type 2 diabetes. We aimed to conduct a systematic literature review and dose-response meta-analysis of evidence from prospective cohorts.

RESEARCH DESIGN AND METHODS

We searched the Cochrane Library, MEDLINE, MEDLINE in-process, Embase, CAB Abstracts, ISI Web of Science, and BIOSIS for prospective studies of GI, GL, and total carbohydrates in relation to risk of type 2 diabetes up to 17 July 2012. Data were extracted from 24 publications on 21 cohort studies. Studies using different exposure categories were combined on the same scale using linear and nonlinear dose-response trends. Summary relative risks (RRs) were estimated using random-effects meta-analysis.

RESULTS

The summary RR was 1.08 per 5 GI units (95% CI 1.02-1.15; P = 0.01), 1.03 per 20 GL units (95% CI 1.00-1.05; P = 0.02), and 0.97 per 50 g/day of carbohydrate (95% CI 0.90-1.06; P = 0.5). Dose-response trends were linear for GI and GL but more complex for total carbohydrate intake. Heterogeneity was high for all exposures (I(2) >50%), partly accounted for by different covariate adjustment and length of follow-up.

CONCLUSIONS

Included studies were observational and should be interpreted cautiously. However, our findings are consistent with protective effects of low dietary GI and GL, quantifying the range of intakes associated with lower risk. Future research could focus on the type of sugars and other carbohydrates associated with greatest risk.

Mediterranean diet and glycaemic load in relation to incidence of type 2 diabetes: results from the Greek cohort of the population-based European Prospective Investigation into Cancer and Nutrition (EPIC)

AIMS/HYPOTHESIS

The role of diet in the prevention of diabetes remains uncertain. The aim of this study was to investigate two different dietary aspects, i.e. adherence to the Mediterranean diet and glycaemic load (GL), in relation to diabetes occurrence.

METHODS

We analysed data from the Greek cohort of the population-based European Prospective Investigation into Cancer and Nutrition (EPIC). From a total of 22,295 participants, actively followed for a median of 11.34 years, 2,330 cases of incident type 2 diabetes were recorded. All participants completed a validated, interviewer-administered semi-quantitative food frequency questionnaire at enrolment. From this information, we calculated a ten point Mediterranean diet score (MDS), reflecting adherence to the traditional Mediterranean diet, as well as the dietary GL. We estimated HRs and the corresponding 95% CIs of diabetes using Cox proportional hazards regression models adjusted for potential confounders.

RESULTS

A higher MDS was inversely associated with diabetes risk (HR 0.88 [95% CI 0.78, 0.99] for MDS ≥ 6 vs MDS ≤ 3). GL was positively associated with diabetes (HR 1.21 [95% CI 1.05, 1.40] for the highest vs the lowest GL quartile). A significant protection of about 20% was found for a diet with a high MDS and a low GL.

CONCLUSIONS/INTERPRETATION

A low GL diet that also adequately adheres to the principles of the traditional Mediterranean diet may reduce the incidence of type 2 diabetes.

Epidemiology and mortality of new-onset diabetes after dialysis: Taiwan national cohort study

OBJECTIVE

We examined the predictors and risks associated with pre-existing versus new-onset diabetes mellitus (DM) after initiation of chronic dialysis therapy in end-stage renal disease (ESRD) patients.

RESEARCH DESIGN AND METHODS

In the Taiwan National Health Insurance Research Database, we examined records of ESRD patients who initiated dialysis between 1999 and 2005. Patients were followed until death, transplant, dialysis withdrawal, or 31 December 2008. Predictors of new-onset DM and mortality were calculated using Cox models.

RESULTS

A total of 51,487 incident dialysis patients were examined in this study, including 25,321 patients with pre-existing DM, 3,346 with new-onset DM, and 22,820 without DM at any time. Patients' age (mean±SD) was 61.8±11.5, 61.6±13.7, and 56.5±16.6 years in pre-existing, new-onset DM, and without DM groups, respectively. The cumulative incidence rate of new-onset DM was 4% at 1 year and 21% at 9 years. Dialysis modality was not a risk factor for new-onset DM (peritoneal dialysis to hemodialysis hazard ratio [HR] of new-onset DM, 0.94 [95% CI 0.83-1.06]). Pre-existing DM was associated with 80% higher death risk (HR 1.81 [95% CI 1.75-1.87]), whereas the new-onset DM was associated with 10% increased death risk (HR 1.10 [95% CI 1.03-1.17]).

CONCLUSIONS

Whereas dialysis modality does not appear to associate with new-onset DM, both pre-existing and new-onset DM are related to higher long-term mortality in maintenance dialysis patients.

Is there a dose-response relation of dietary glycemic load to risk of type 2 diabetes? Meta-analysis of prospective cohort studies

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.

Carbohydrate quality is not associated with liver enzyme activity and plasma TAG and HDL concentrations over 5 years in an older population

Non-alcoholic fatty liver disease (NAFLD) is closely associated with insulin resistance and obesity. Hence, carbohydrate quality could be of relevance to the risk of NAFLD, but prospective data are lacking. The aim of the present study was to investigate longitudinal associations between carbohydrate quality (including dietary glycaemic index (GI) and intakes of sugar, starch and fibre) and markers of liver function in an older Australian population. The analysis was based on 866 participants ( ≥ 49 years) of the Blue Mountains Eye Study with fasting blood specimens and dietary intake data at baseline and 5-year follow-up. Multi-level mixed regression analysis was used to relate dietary GI and sugar, starch and fibre intake to the liver enzymes alanine aminotransferase (ALT) and γ-glutamyltransferase (GGT), as well as fasting TAG and HDL-cholesterol (HDL-C). After adjustment for potential confounding factors, a lower fibre intake was cross-sectionally related to higher GGT (P= 0.02) and fasting TAG (P= 0.002) levels, with fruit fibre being the most relevant fibre source (P= 0.095 for GGT; P= 0.003 for TAG). A higher dietary GI was associated with lower HDL-C (P= 0.046). Changes in carbohydrate quality during 5 years were not related to changes in ALT, GGT, TAG or HDL-C (P≥ 0.08). In conclusion, the absence of longitudinal associations between carbohydrate quality and liver enzymes and serum lipids in this older population does not support a major role of carbohydrate nutrition in liver function among the elderly.

Dietary glycemic index, glycemic load, and digestible carbohydrate intake are not associated with risk of type 2 diabetes in eight European countries

The association of glycemic index (GI) and glycemic load (GL) with the risk of type 2 diabetes remains unclear. We investigated associations of dietary GI, GL, and digestible carbohydrate with incident type 2 diabetes. We performed a case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition Study, including a random subcohort (n = 16,835) and incident type 2 diabetes cases (n = 12,403). The median follow-up time was 12 y. Baseline dietary intakes were assessed using country-specific dietary questionnaires. Country-specific HR were calculated and pooled using random effects meta-analysis. Dietary GI, GL, and digestible carbohydrate in the subcohort were (mean ± SD) 56 ± 4, 127 ± 23, and 226 ± 36 g/d, respectively. After adjustment for confounders, GI and GL were not associated with incident diabetes [HR highest vs. lowest quartile (HR(Q4)) for GI: 1.05 (95% CI = 0.96, 1.16); HR(Q4) for GL: 1.07 (95% CI = 0.95, 1.20)]. Digestible carbohydrate intake was not associated with incident diabetes [HR(Q4): 0.98 (95% CI = 0.86, 1.10)]. In additional analyses, we found that discrepancies in the GI value assignment to foods possibly explain differences in GI associations with diabetes within the same study population. In conclusion, an expansion of the GI tables and systematic GI value assignment to foods may be needed to improve the validity of GI values derived in such studies, after which GI associations may need reevaluation. Our study shows that digestible carbohydrate intake is not associated with diabetes risk and suggests that diabetes risk with high-GI and -GL diets may be more modest than initial studies suggested.

Dietary glycemic index and glycemic load in relation to HbA1c in Japanese obese adults: a cross-sectional analysis of the Saku Control Obesity Program

BACKGROUND

Dietary glycemic index or load is thought to play an important role in glucose metabolism. However, few studies have investigated the relation between glycemic index (GI) or load (GL) and glycemia in Asian populations. In this cross-sectional analysis of a randomized controlled trial, the Saku Control Obesity Program, we examined the relation between the baseline GI or GL and glycemia (HbA1c and fasting plasma glucose [FPG] levels), insulin resistance (HOMA-IR), β-cell function (HOMA-β), and other metabolic risk factors (lipid levels, diastolic and systolic blood pressure, and adiposity measures).

METHODS

The participants were 227 obese Japanese women and men. We used multiple linear regression models and logistic regression models to adjust for potential confounding factors such as age, sex, visceral fat area, total energy intake, and physical activity levels.

RESULTS

After adjustments for potential confounding factors, GI was not associated with HbA1c, but GL was positively associated with HbA1c. For increasing quartiles of GI, the adjusted mean HbA1c were 6.3%, 6.7%, 6.4%, and 6.4% (P for trend = 0.991). For increasing quartiles of GL, the adjusted mean HbA1c were 6.2%, 6.2%, 6.6%, and 6.5% (P for trend = 0.044). In addition, among participants with HbA1c ≥ 7.0%, 20 out of 28 (71%) had a high GL (≥ median); the adjusted odds ratio for HbA1c ≥ 7.0% among participants with higher GL was 3.1 (95% confidence interval [CI] = 1.2 to 8.1) compared to the participants with a lower GL (

CONCLUSIONS

Our findings suggest that participants with poor glycemic control tend to have a higher GL in an obese Japanese population.

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Affiliation(s)

Maki Goto Department of Diabetes Research, Diabetes Research Center, National Center for Global Health and Medicine, Tokyo, Japan.
Akemi Morita
Atsushi Goto
Satoshi Sasaki
Naomi Aiba
Takuro Shimbo
Yasuo Terauchi
Motohiko Miyachi
Mitsuhiko Noda
Shaw Watanabe

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Glycemic index and glycemic load are associated with some cardiovascular risk factors among the PREMIER study participants

BACKGROUND

The clinical significance of glycemic index (GI) and glycemic load (GL) is inconclusive.

OBJECTIVE

This study was conducted to examine the association of GI and GL with clinical cardiovascular disease (CVD) risk factors including body weight, blood pressure (BP), serum lipids, fasting glucose, insulin and homocysteine over time among the PREMIER participants.

DESIGN

PREMIER was an 18-month randomized lifestyle intervention trial, conducted from 2000 to 2002, designed to help participants reduce BP by following the Dietary Approaches to Stop Hypertension (DASH) dietary pattern, losing weight, reducing sodium and increasing physical activity. GI and GL were estimated from 24 h diet recall data at baseline, 6 and 18 months after intervention. PROC MIXED model was used to examine the association of changes in GI or GL with changes in CVD risk factors.

RESULTS

A total of 756 randomized participants, 62% females and 34% African Americans and who averaged 50.0±0.3 years old and 95.3±0.7 kg, were included in this report. Neither GI nor GL changes was associated with changes in any risk factors at 6 months. At 18 months, however, the GI change was significantly and positively associated with total cholesterol (TC) change only (p<0.05, β=23.80±12.11 mg/dL or 0.62±0.31 mmol/L) with a significant age interaction. The GL change was significantly associated with TC (p=0.02, β=0.28±0.15 mg/dL or 0.01±0.00 mmol/L) positively and with low density lipoprotein cholesterol (LDL-C) changes negatively (p=0.03, β=-0.01±0.00 mg/dL or -0.00±0.00 mmol/L), and significant age interactions were observed for both.

CONCLUSIONS

GI and GL was associated with TC and LDL-C after controlling for energy, fat and fiber intake and other potential confounders and the associations were modified by age. Further investigation into this relationship is important because of its potential clinical impact.

Low-glycemic load decreases postprandial insulin and glucose and increases postprandial ghrelin in white but not black women

Alterations in appetite hormones favoring increased postprandial satiety have been implicated in both the glycemic control and potential weight-loss benefits of a low-glycemic diet. Racial differences exist in dietary glycemic load and appetite hormone concentrations. This study examined the impact of glycemic load on appetite hormones in 20 black women [10 normal weight, BMI = 22.8 ± 1.42 (mean ± SD); 10 obese, BMI = 35.1 ± 2.77] and 20 white women (10 normal weight, BMI = 22.9 ± 1.45; 10 obese, BMI = 34.3 ± 2.77). Each woman completed two 4.5-d weight-maintenance, mixed-macronutrient, high-glycemic vs. low-glycemic load diets that concluded with a test meal of identical composition. Blood samples collected before and serially for 3 h after each test meal were assayed for plasma ghrelin and serum insulin and glucose concentrations. Compared with the high-glycemic load meal, the low-glycemic load meal was associated with lower insulin(AUC) (P = 0.02), glucose(AUC) (P = 0.01), and urge to eat ratings (P = 0.05) but with higher ghrelin(AUC) (P = 0.008). These results suggest the satiating effect of a low-glycemic load meal is not directly linked to enhanced postprandial suppression of ghrelin. Notably, these effects were significant among white but not black women, suggesting that black women may be less sensitive than white women to the glucoregulatory effects of a low-glycemic load. These findings add to a growing literature demonstrating racial differences in postprandial appetite hormone responses. If reproducible, these findings have implications for individualized diet prescription for the purposes of glucose or weight control in women.

Evidence-based guideline of the German Nutrition Society: carbohydrate intake and prevention of nutrition-related diseases

The relative contribution of nutrition-related chronic diseases to the total disease burden of the society and the health care costs has risen continuously over the last decades. Thus, there is an urgent necessity to better exploit the potential of dietary prevention of diseases. Carbohydrates play a major role in human nutrition - next to fat, carbohydrates are the second biggest group of energy-yielding nutrients. Obesity, type 2 diabetes mellitus, dyslipoproteinaemia, hypertension, metabolic syndrome, coronary heart disease and cancer are wide-spread diseases, in which carbohydrates could have a pathophysiologic relevance. Correspondingly, modification of carbohydrate intake could have a preventive potential. In the present evidence-based guideline of the German Nutrition Society, the potential role of carbohydrates in the primary prevention of the named diseases was judged systematically. The major findings were: a high carbohydrate intake at the expense of total fat and saturated fatty acids reduces the concentrations of total, LDL and HDL cholesterol. A high carbohydrate consumption at the expense of polyunsaturated fatty acids increases total and LDL cholesterol, but reduces HDL cholesterol. Regardless of the type of fat being replaced, a high carbohydrate intake promotes an increase in the triglyceride concentration. Furthermore, a high consumption of sugar-sweetened beverages increases the risk of obesity and type 2 diabetes mellitus, whereas a high dietary fibre intake, mainly from whole-grain products, reduces the risk of obesity, type 2 diabetes mellitus, dyslipoproteinaemia, cardiovascular disease and colorectal cancer at varying evidence levels. The practical consequences for current dietary recommendations are presented.

Karma eaters: the politics of food and fat in women's land communities in the United States

Why is thinness so important among women who have largely rejected mainstream definitions of femininity? The idea of health has great cultural power and has come to symbolize not simply bodily but also spiritual, social, and moral well-being. These ideas permeate U.S. culture, and in women's land communities, the virtue of hunger and the morality of health take on differently inflected but no less potent meanings. Ironically, in a context where women reject many gender restrictions--restrictions increasingly, as Sandra Bartky notes, focused on the female body-the importance of the thin (and thus properly feminine) body persists through the symbolism of health and virtue.

Dietary glycaemic index and glycaemic load in relation to the risk of type 2 diabetes: a meta-analysis of prospective cohort studies

Epidemiological studies of dietary glycaemic index (GI) and glycaemic load (GL) in relation to diabetes risk have yielded inconsistent results. We aimed to examine the associations between dietary GI and GL and the risk of type 2 diabetes by conducting a meta-analysis of prospective cohort studies. Relevant studies were identified by a PubMed database search up to February 2011. Reference lists from retrieved articles were also reviewed. We included prospective cohort studies that reported risk estimates with 95 % CI for the associations between dietary GI and GL and the risk of type 2 diabetes. Either a fixed- or random-effects model was used to compute the summary relative risk (RR). We identified thirteen prospective cohort studies of dietary GI or GL related to diabetes risk. The summary RR of type 2 diabetes for the highest category of the GI compared with the lowest was 1·16 (95 % CI 1·06, 1·26;n12), with moderate evidence of heterogeneity (P = 0·02,I2 = 50·8 %). For the GL, the summary RR was 1·20 (95 % CI 1·11, 1·30;n12), with little evidence of heterogeneity (P = 0·10,I2 = 34·8 %). No evidence of publication bias was observed. In addition, the associations persisted and remained statistically significant in the sensitivity analyses. In conclusion, the present meta-analysis provides further evidence in support of significantly positive associations between dietary GI and GL and the risk of type 2 diabetes. Reducing the intake of high-GI foods may bring benefits in diabetes prevention.

Glycemic index and glycemic load and their association with C-reactive protein and incident type 2 diabetes

Objective. To investigate whether the Glycemic Index (GI) or Glycemic Load (GL) of a diet is associated with C-reactive Protein (CRP) and risk of type 2 diabetes in a prospective study. Materials and Methods. Our analysis included 4,366 participants who did not have diabetes at baseline. During follow-up 456 diabetes cases were confirmed. Dietary GI and GL were derived from a food-frequency questionnaire and its association with CRP was examined cross-sectionally using linear regression models. The association of GI and GL with diabetes incidence was examined using Cox proportional hazard models. Results. GL, but not GI, was associated with lnCRP at baseline (b_GL = 0.11 per 50 units; P = .01). When comparing the highest to the lowest tertile of GI with respect to diabetes incidence, a Relative Risk (RR) of 0.95 [95%CI 0.75, 1.21] was found after adjustment for lifestyle and nutritional factors. For GL the RR for diabetes incidence was 1.00 [95%CI 0.74, 1.36]. Additional adjustment for CRP did not change RRs. Conclusion. Since GI was not associated with CRP and risk of type 2 diabetes, it is unlikely that a high GI diet induces the previously shown positive association between CRP and risk of type 2 diabetes by increasing CRP concentrations.

Relationship between dietary intake and the development of type 2 diabetes in a Chinese population: the Hong Kong Dietary Survey

OBJECTIVE

To study the relationship between dietary intake and the development of type 2 diabetes among Chinese adults.

DESIGN

A prospective cohort study. Dietary assessment was carried out using a validated FFQ. Principal component analysis was used to identify dietary patterns. Dietary glycaemic load and variety of snacks were also calculated.

SETTING

A hospital-based centre at the Queen Mary Hospital in Hong Kong SAR, China.

SUBJECTS

A total of 1010 Chinese adults aged 25-74 years who participated in a territory-wide dietary and cardiovascular risk factor prevalence survey in 1995-1996 were followed up for 9-14 years for the development of diabetes.

RESULTS

A total of 690 (68·3 %) individuals completed follow-up during 2005-2008 and seventy-four cases of diabetes were identified over the follow-up period. Four dietary patterns were identified ('more snacks and drinks', 'more vegetables, fruits and fish', 'more meat and milk products' and 'more refined grains'). After adjustment for age, sex, BMI, waist-to-hip ratio, smoking, alcohol intake, participation in exercise/sports and family history of diabetes, the more vegetables, fruits and fish pattern was associated with a 14 % lower risk (OR per 1 sd increase in score = 0·76; 95 % CI 0·58, 0·99), whereas the more meat and milk products pattern was associated with a 39 % greater risk of diabetes (OR per 1 sd increase in score = 1·39; 95 % CI 1·04, 1·84). Dietary glycaemic load, rice intake, snack intake and variety of snacks were not independently associated with diabetes.

CONCLUSIONS

The more vegetables, fruits and fish pattern was associated with reduced risk and the more meat and milk products pattern was associated with an increased risk of diabetes.

Low-, medium- and high-glycaemic index carbohydrates and risk of type 2 diabetes in men

Findings on dietary glycaemic index (GI) and glycaemic load (GL) as risk factors for type 2 diabetes have been controversial. We examined the associations of dietary GI and GL and the associations of substitution of lower-GI carbohydrates for higher-GI carbohydrates with diabetes risk in a cohort of Finnish men. The cohort consisted of 25 943 male smokers aged 50-69 years. Diet was assessed, at baseline, using a validated diet history questionnaire. During a 12-year follow-up, 1098 incident diabetes cases were identified from a national register. Cox proportional hazard modelling was used to estimate the risk of diabetes, and multivariate nutrient density models were used to examine the effects of substitution of different carbohydrates. Dietary GI and GL were not associated with diabetes risk; multivariate relative risk (RR) for highest v. lowest quintile for GI was 0·87 (95 % CI 0·71, 1·07) and for GL 0·88 (95 % CI 0·65, 1·17). Substitution of medium-GI carbohydrates for high-GI carbohydrates was inversely associated with diabetes risk (multivariate RR for highest v. lowest quintile 0·75, 95 % CI 0·59, 0·96), but substitution of low-GI carbohydrates for medium- or high-GI carbohydrates was not associated with the risk. In conclusion, dietary GI and GL were not associated with diabetes risk, and substitutions of lower-GI carbohydrates for higher-GI carbohydrates were not consistently associated with a lower diabetes risk. The associations of dietary GI and GL with diabetes risk should be interpreted by considering nutritional correlates, as foods may have different properties that affect risk.

Targeting dietary fat or glycemic load in the treatment of obesity and type 2 diabetes: a randomized controlled trial

AIMS

To compare the effects of lifestyle modification programs that prescribe low-glycemic load (GL) vs. low-fat diets in a randomized trial.

METHODS

Seventy-nine obese adults with type 2 diabetes received low-fat or low-GL dietary instruction, delivered in 40-week lifestyle modification programs with identical goals for calorie intake and physical activity. Changes in weight, HbA(1c), and other metabolic parameters were compared at weeks 20 and 40.

RESULTS

Weight loss did not differ between groups at week 20 (low-fat: -5.7±3.7%; low-GL: -6.7±4.4%, p=.26) or week 40 (low-fat: -4.5±7.5%; low-GL: -6.4±8.2%, p=.28). Adjusting for changes in antidiabetic medications, subjects on the low-GL diet had larger reductions in HbA(1c) than those on the low-fat diet at week 20 (low-fat: -0.3±0.6%; low-GL: -0.7±0.6%, p=.01), and week 40 (low-fat: -0.1±1.2%; low-GL: -0.8±1.3%; p=.01). Groups did not differ significantly on any other metabolic outcomes (p≥.06).

CONCLUSIONS

Results suggest that targeting GL, rather than dietary fat, in a low-calorie diet can significantly enhance the effect of weight loss on HbA(1c) in patients with type 2 diabetes.

Informing food choices and health outcomes by use of the dietary glycemic index

Considerable epidemiologic evidence links consuming lower glycemic index (GI) diets with good health, particularly upon aging. The GI is a kinetic parameter that reflects the ability of carbohydrate (CHO) contained in consumed foods to raise blood glucose in vivo. Newer nutritional, clinical, and experimental data link intake of lower dietary GI foods to favorable outcomes of chronic diseases, and compel further examination of the record. Based upon the new information there are two specific questions: 1) should the GI concept be promoted as a way to prolong health, and 2) should food labels contain GI information? Further, what are the remaining concerns about methodological issues and consistency of epidemiological data and clinical trials that need to be resolved in order to exploit the benefits of consuming lower GI diets? These issues are addressed in this review.