Quantity Of Dietary Carbohydrate Research Articles

114-OR: Genetic Variants in GIPR and Effects of Dietary Carbohydrate Quantity and Quality on Glycemic Responses to an Oral Glucose Load—The OmniCarb Trial

The gut incretin hormone, glucose-dependent insulinotropic polypeptide (GIP), may play a pivotal role in mediating adverse effects of high glycemic index (GI) foods on metabolic diseases. GIP exerts its effects by binding to a receptor, GIPR; genome-wide association studies have identified variants in the GIPR region related to type 2 diabetes (T2D) and glycemic/GIP responses to glucose tolerance tests. We examined whether GIPR variants were related to impaired glycemic responses during oral glucose tolerance tests (OGTTs) after consuming 4 diets (each for 5 weeks) with different carbohydrate (Carb) content and GI levels in the OmniCarb randomized crossover feeding trial. A genetic risk score (GRS) was calculated by counting T2D-risk alleles of SNPs rs1800437, rs11671664, and rs2238689 at GIPR (n=146). We found that GRS was related to greater glycemic responses after consuming a high GI/high Carb diet, regardless of baseline glycemic status (Fig). When testing diet replacement effects, combined effects of high GI and high Carb (vs. low GI/low Carb) on glycemic responses were significantly modified by GRS (Pinteraction<0.05). In conclusion, T2D-risk-related GIPR variants modified the effects of dietary carbohydrates on glucose tolerance. GIPR variants may be related to deteriorating glucose tolerance after eating a high GI, high Carb diet. Disclosure Y.Heianza: None. X.Wang: None. Q.Xue: None. L.J.Appel: None. F.Sacks: None. L.Qi: None. Funding National Institutes of Health (2P20GM109036-06A1-7233, DK091718, DK100383, DK115679)

Contrasting Carbohydrate Quantity and Quality and the Effects on Plasma Saturated and Monounsaturated Fatty Acids in Healthy Adults: A Randomized Controlled Trial

BackgroundIt is unclear whether moderate differences in dietary carbohydrate quantity and quality influence plasma FAs in the lipogenic pathway in healthy adults. ObjectivesWe investigated the effects of different carbohydrate quantities and quality on plasma palmitate concentrations (primary outcome) and other saturated and MUFAs in the lipogenic pathway. MethodsTwenty healthy participants were randomly assigned, and 18 (50% women; age: 22–72 y; BMI: 18.2–32.7 kg/m2 and BMI was measured in kg/m2) started the cross-over intervention. During each 3-wk period (separated by a 1-wk washout period), 3 diets were consumed (all foods provided) in random order: low-carbohydrate (LC) (38% energy (E) carbohydrates, 25–35 g fiber/d, 0% E added sugars); high-carbohydrate/high-fiber (HCF) (53% E carbohydrates, 25–35 g fiber/d, 0% E added sugars); and high-carbohydrate/high-sugar (HCS) (53% E carbohydrates, 19–21 g fiber/d, 15% E added sugars). Individual FAs were measured proportionally to total FAs by GC in plasma cholesteryl esters, phospholipids, and TGs. False discovery rate–adjusted repeated measures ANOVA [ANOVA-false discovery rate (FDR)] was used to compare outcomes. ResultsThe self-reported intakes of carbohydrates and added- and free sugars were; 30.6% E and 7.4% E in LC, 41.4% E and 6.9% E in HCF, and 45.7% E and 10.3% in HCS. Plasma palmitate did not differ between the diet periods (ANOVA FDR P > 0.43, n = 18). After HCS, myristate concentrations in cholesterol esters and phospholipids were ≥19% higher than LC and ≥22% higher than HCF (P = 0.005). After LC, palmitoleate in TG was 6% lower compared with HCF and 7% compared with HCS (P = 0.041). Body weight differed (≤0.75 kg) between diets before FDR correction. ConclusionsDifferent carbohydrate quantity and quality do not influence plasma palmitate concentrations after 3 wk in healthy Swedish adults, whereas myristate increased after the moderately higher intake of carbohydrate/high-sugar, but not carbohydrate/high-fiber. Whether plasma myristate is more responsive than palmitate to differences in carbohydrate intake requires further study, especially considering that participants deviated from the planned dietary targets. J Nutr 20XX;xx:xx–xx.This trial was registered at clinicaltrials.gov as NCT03295448.

Dietary carbohydrate quantity and quality and risk of cardiovascular disease, all-cause, cardiovascular and cancer mortality: A systematic review and meta-analysis

Evidence remains conflicted on the association between dietary carbohydrate quantity and quality and risk of cardiovascular disease, all-cause, cardiovascular and cancer mortality, and such meta-analyses are lacking. The study aimed to conduct a systematic review and meta-analysis to synthesize the knowledge about their associations and to explore the dose-response relations. We comprehensively searched PubMed, EMBASE, and Web of Science up to March 2022 for observational studies investigating the associations in adults. Random effect model was used to estimate the summary relative risks (RRs) and 95% confidence intervals (CIs) and the dose-response association was explored by restricted cubic splines. We obtained the data from 41 eligible studies. Compared with participants with lowest dietary carbohydrate intake, those with highest intake had an RR of 1.10 (95% CI 1.03-1.17, I2=52.8%) for cardiovascular disease, 1.10 (0.98-1.24, I2=65.5%) for coronary heart disease (CHD), 1.20 (1.08-1.34, I2=0) for stroke, 1.07 (1.00-1.14, I2=61.9%) for all-cause mortality, 1.02 (0.92-1.14, I2=51.3%) for cardiovascular mortality, and 1.01 (0.89-1.13, I2=56.7%) for cancer mortality. For each 5 %E increase in dietary carbohydrate intake, the summary RR was 1.02 (1.00-1.04, I2=66.8%) for cardiovascular disease, 1.04 (1.01-1.06, I2=0) for stroke but not significant for other outcomes. Restricted cubic splines showed linear associations with risk of cardiovascular disease (Pnon-linearity=0.143), CHD (Pnon-linearity=0.508), stroke (Pnon-linearity=0.654) and non-linear associations with all-cause mortality (Pnon-linearity=0.008) and cardiovascular mortality (Pnon-linearity=0.055). Limited studies were found on the association of cardiovascular disease and mortality with dietary carbohydrate quality using a multidimensional and integrated indicator. Increased consumption of dietary carbohydrate intake is associated with increased risk of cardiovascular disease, stroke, and all-cause mortality. Linear relation was found for cardiovascular disease and stroke but non-linear relation for all-cause mortality. More studies are warranted to investigate the association of dietary carbohydrate quality using a combined indicator and cardiovascular disease and mortality.

Interaction of MC4R rs17782313 variants and dietary carbohydrate quantity and quality on basal metabolic rate and general and central obesity in overweight/obese women: a cross-sectional study

BackgroundRecent studies have shown that dietary carbohydrate quantity and quality as well as genetic variants may contribute to determining the metabolic rate and general and central obesity. This study aimed to examine interactions between melanocortin 4 receptor gene (MC4R) rs17782313 and dietary carbohydrate intake, glycemic index (GI), and glycemic load (GL) on body mass index (BMI), waist circumferences (WC), basal metabolic rate (BMR), and BMR/kg in overweight/obese women.MethodsA total of 282 Iranian women (BMI ≥ 25) aged 18–56 years were enrolled in this cross-sectional study. All participants were assessed for blood parameters, body composition, BMR, and dietary intake. Dietary carbohydrate intake, GI, and GL were determined using a valid, reliable 147-item food frequency questionnaire. MC4R rs17782313 was genotyped by the restriction fragment length polymorphism (PCR-RFLP) method.ResultsAfter adjustment for age and energy intake, significant interactions were observed between carbohydrate intake and MC4R rs17782313 in terms of BMI (P Interaction = 0.007), WC (P Interaction = 0.02), and BMR/kg (P Interaction = 0.003) in this way that higher carbohydrate intake, compared with lower intake, was associated with an increase in BMI and WC for individuals with C allele carriers (TC + CC genotypes), while related to an increase in BMR/kg for those carrying the TT genotype. No significant interaction was found between MC4R rs17782313 and GI and GL on BMI, WC, BMR/kg, and BMR.ConclusionsInteractions between the MC4R rs17782313 and carbohydrate intake probably can have an effect on BMI, WC, and BMR/kg in overweight/obese women.

Dietary Carbohydrate Intake, Dietary Glycemic Load and Outcomes of In Vitro Fertilization: Findings from an Observational Italian Cohort Study.

In recent decades, increasing attention has been paid to the influence of diet on reproductive health. Carbohydrates in diet affect glucose metabolism and multiple evidences showed the key role of insulin sensitivity in regulating female fertility. We designed a prospective cohort study to investigate the relation between dietary carbohydrate intake, glycemic load (GL) and the outcomes of assisted reproduction. A population of 494 female partners of couples referring to an Italian Fertility Center and eligible for in vitro fertilization (IVF) were enrolled in the study. On the day of the oocyte retrieval, information on their diet was obtained using a validated food frequency questionnaire (FFQ). We calculated the relative risk and 95% confidence interval of embryo transfer, clinical pregnancy and live birth according to the following dietary exposures: GL, glycemic index (GI) as well as the daily carbohydrate and fiber intake. A multiple regression model was used to account for the confounders. After adjusting for age, college degree, body mass index (BMI), leisure physical activity and previous assisted reproduction techniques (ART) cycles, no significant association was observed between the considered dietary exposures and the IVF outcomes. The roles of GL, carbohydrate intake and GI were assessed in strata of the cause of infertility and body mass index and no relation emerged in this further analysis. We found no clear association between the dietary carbohydrate quantity and quality and IVF outcomes in a cohort of infertile Italian women.

Association between quality and quantity of dietary carbohydrate and pregnancy-induced hypertension: A case–control study

Pregnancy-induced hypertension (PIH) is a pregnancy-specific disorder that increases maternal and infant mortality and morbidity. The quantity and quality of consumed carbohydrates are probably the main dietary factors affecting blood pressure. The present study aimed to evaluate the association of carbohydrate quality and quantity with PIH. This case-control study was performed on 202 pregnant women with or without PIH. The dietary data were collected using 168-item semi-quantitative food frequency questionnaires. Daily glycemic index (GI) and glycemic load (GL), ratio of whole grains to total grains, ratio of solid carbohydrates to total carbohydrates, dietary fiber and carbohydrate intake, and carbohydrate quality index (CQI) were calculated and their associations with PIH were evaluated using logistic regression. We eliminated collinearity within independent variables using factor analysis and then with evaluating the relationship between extracted factors and PIH. In pregnant women in whom the daily carbohydrate intake and GL were higher than median increased frequency of PIH compared to whom had lower than median ones (OR=3.23, 95% CI 1.46-7.17, and P=0.004; OR=2.60, 95% CI 1.21-5.56; and P=0.035, respectively). Furthermore, we showed a significant inverse association between extracted factor that was mostly related to total fiber intake frequency of PIH (OR=0.45; 95% CI 0.20-0.97, and P=0.049 when higher than median values compared to lower than ones). The GI, ratio of whole grains to total grains, ratio of solid carbohydrates to total carbohydrates, and CQI did not associate with PIH. These findings suggest that carbohydrate intake and GL are related to higher and daily fiber intake to lower frequency of PIH.

Pre-pregnancy dietary carbohydrate quantity and quality, and risk of developing gestational diabetes: the Australian Longitudinal Study on Women's Health.

Carbohydrate quantity and quality affect postprandial glucose response, glucose metabolism and risk of type 2 diabetes. The aim of this study was to examine the association of pre-pregnancy dietary carbohydrate quantity and quality with the risk of developing gestational diabetes mellitus (GDM). We used data from the Australian Longitudinal Study on Women's Health that included 3607 women aged 25-30 years without diabetes who were followed up between 2003 and 2015. We examined carbohydrate quantity (total carbohydrate intake and a low-carbohydrate diet (LCD) score) and carbohydrate subtypes indicating quality (fibre, total sugar intake, glycaemic index, glycaemic load and intake of carbohydrate-rich food groups). Relative risks (RR) for development of GDM were estimated using multivariable regression models with generalised estimating equations. During 12 years of follow-up, 285 cases of GDM were documented in 6263 pregnancies (4·6 %). The LCD score, reflecting relatively high fat and protein intake and low carbohydrate intake, was positively associated with GDM risk (RR 1·54; 95 % CI 1·10, 2·15), highest quartile v. lowest quartile). Women in the quartile with highest fibre intake had a 33 % lower risk of GDM (RR 0·67; 95 % CI 0·45, 0·96)). Higher intakes of fruit (0·95 per 50 g/d; 95 % CI 0·90, 0·99) and fruit juice (0·89 per 100 g/d; 95 % CI 0·80, 1·00)) were inversely associated with GDM, whereas cereal intake was associated with a higher risk of GDM (RR 1·05 per 20 g/d; 95 % CI 1·01, 1·07)). Thus, a relatively low carbohydrate and high fat and protein intake may increase the risk of GDM, whereas higher fibre intake could decrease the risk of GDM. It is especially important to take the source of carbohydrates into account.

Quantity and Quality of Carbohydrate Intake during Pregnancy, Newborn Body Fatness and Cardiac Autonomic Control: Conferred Cardiovascular Risk?

The fetal environment has an important influence on health and disease over the life course. Maternal nutritional status during pregnancy is potentially a powerful contributor to the intrauterine environment, and may alter offspring physiology and later life cardio-metabolic risk. Putative early life markers of cardio-metabolic risk include newborn body fatness and cardiac autonomic control. We sought to determine whether maternal dietary carbohydrate quantity and/or quality during pregnancy are associated with newborn body composition and cardiac autonomic function. Maternal diet during pregnancy was assessed in 142 mother-infant pairs using a validated food frequency questionnaire. Infant adiposity and body composition were assessed at birth using air-displacement plethysmography. Cardiac autonomic function was assessed as heart rate variability. The quantity of carbohydrates consumed during pregnancy, as a percentage of total energy intake, was not associated with meaningful differences in offspring birth weight, adiposity or heart rate variability (p > 0.05). There was some evidence that maternal carbohydrate quality, specifically higher fibre and lower glycemic index, is associated with higher heart rate variability in the newborn offspring (p = 0.06). This suggests that poor maternal carbohydrate quality may be an important population-level inter-generational risk factor for later cardiac and hemodynamic risk of their offspring.

Glycaemic index, glycaemic load and risk of cutaneous melanoma in a population-based, case-control study.

Glycaemic index (GI) and glycaemic load (GL) are indicators of dietary carbohydrate quantity and quality and have been associated with increased risk of certain cancers and type 2 diabetes. Insulin resistance has been associated with increased melanoma risk. However, GI and GL have not been investigated for melanoma. We present the first study to examine the possible association of GI and GL with melanoma risk. We carried out a population-based, case-control study involving 380 incident cases of cutaneous melanoma and 719 age- and sex-matched controls in a northern Italian region. Dietary GI and GL were computed for each subject using data from a self-administered, semi-quantitative food frequency questionnaire. We computed the odds ratio (OR) for melanoma according to quintiles of distribution of GL and GL among controls. A direct association between melanoma risk and GL emerged in females (OR 2·38; 95 % CI 1·25, 4·52 for the highest v. the lowest quintile of GL score, P for trend 0·070) but not in males. The association in females persisted in the multivariable analysis after adjusting for several potential confounders. There was no evidence of an association between GI and melanoma risk. GL might be associated with melanoma risk in females.

Abstract P317: Dietary Carbohydrate Quantity and Quality Measures and Risk of Stroke

Background: Dietary carbohydrates with high glycemic index and low in cereal fiber have been associated with increased risk of diabetes, a risk factor for stroke. Few prospective studies have examined the relation between measures of carbohydrate quality and risk of incident stroke. The relation between carbohydrate to fiber ratio and stroke risk remains unknown. Methods: We prospectively examined the associations of dietary carbohydrate quantity and quality measures (total carbohydrate, fiber [total, cereal, fruit and vegetable], glycemic index and load, and carbohydrate/fiber ratio) and risk of incident stroke among 40,689 men in the Health Professionals Follow-up Study, aged 40 to 75 years and free of diagnosed cardiovascular disease and cancer at baseline in 1986. Diet was collected using a validated questionnaire every 4 years. We calculated the hazard ratio of total, ischemic, and hemorrhagic strokes by quintiles of energy-adjusted intake of dietary variables using multivariate Cox proportional hazard models. Multivariate models were adjusted for age, lifestyle (BMI, smoking, alcohol, physical activity, multivitamins and aspirin use), history of diseases (family history of CHD, baseline history of hypertension, diabetes and hypercholesterolemia) and diet (total energy, red meat, magnesium, polyunsaturated fat to saturated fat ratio and trans fat). Results: During 24 years of follow-up, 1,530 total stroke events (including 847 ischemic, 178 hemorrhagic and 505 unspecified types) were documented. In multivariate analyses adjusted for age, lifestyle risk factors, history of diseases and total energy intake, carbohydrate (RR=0.74, 95% CI: 0.61 - 0.91, Ptrend 0.008), cereal fiber (RR=0.77, 95% CI: 0.64 - 0.93, Ptrend 0.003) and glycemic load (RR=0.78, 95% CI: 0.64 - 0.95, Ptrend 0.03) were associated with reduced risk of total stroke, comparing the extreme quintiles. With further adjustment for dietary variables, these associations were attenuated to non-significant levels, carbohydrate (RR=0.84, 95% CI: 0.67 - 1.05, Ptrend 0.20), cereal fiber (RR=0.91, 95% CI: 0.73 - 1.14, Ptrend 0.40) and glycemic load (RR=0.84, 95% CI: 0.68 - 1.05, Ptrend 0.26). Vegetable, fruit and total fiber, glycemic index and carbohydrate to fiber ratio were also not significantly associated with incident stroke risk. The results for total stroke were relatively similar to those for ischemic and hemorrhagic stroke types. Conclusions: Consumption of high quality carbohydrate foods did not appear to confer protection against incident stroke risk among this population of US men.

Dietary carbohydrate quantity and quality in relation to obesity: A pooled analysis of three Finnish population-based studies.

The relationship between carbohydrate intake, dietary glycaemic index (GI) and load (GL), and obesity remains unsolved. Sugar intake and obesity represent a timely topic, but studies on sugar subcategories are scarce. We aimed to study whether total carbohydrate, sucrose, lactose, fibre, dietary GI, and GL are associated with obesity in 25-79-year-old Finns. Our pooled analysis included three cross-sectional population-based studies: the DILGOM Study (n = 4842), the Helsinki Birth Cohort Study (n =1979), and the Health 2000 Survey (n = 5521). Diet was assessed by a validated food-frequency questionnaire, and anthropometric measurements were collected by standardised protocols. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated using logistic regression analysis. In the model, which included sex, age, education, smoking, physical activity, and energy intake, the likelihood of being obese (body mass index ⩾ 30 kg/m(2)) appeared lower in the highest quartiles of total carbohydrate (OR 0.65; 95% CI 0.57-0.74; P for trend < 0.0001), sucrose (OR 0.53; 95% CI 0.47-0.61; P < 0.0001), and dietary GL (OR 0.64; 95% CI 0.56-0.73; P < 0.0001) compared to the lowest quartiles. In contrast, dietary GI did not associate with obesity. Fibre intake associated inversely with abdominal obesity (OR 0.80; 95% CI 0.71-0.90; P < 0.001). The inverse sucrose-obesity relationship appeared stronger in high fruit consumers compared to low fruit consumers (P for interaction 0.02). CONCLUSIONS ALTHOUGH MOST OF THE STUDIED CARBOHYDRATE EXPOSURES WERE ASSOCIATED WITH A DIMINISHED LIKELIHOOD OF BEING OBESE, PROSPECTIVE STUDIES ARE NEEDED TO ASSESS TEMPORAL RELATIONS TO SUPPORT CAUSAL INFERENCE.

Adolescent and Early Adulthood Dietary Carbohydrate Quantity and Quality in Relation to Breast Cancer Risk.

We investigated quantity and quality of dietary carbohydrate as well as insulin load and insulin index during adolescence and also early adulthood in relation to risk of breast cancer in the Nurses' Health Study II. During 20 years of follow-up of 90,534 premenopausal women who completed a diet questionnaire in 1991, 2,833 invasive breast cancer cases were documented. In 1998, 44,263 of these women also completed a questionnaire about their diet during high school; among these women, we documented 1,118 cases of breast cancer. Multivariable-adjusted Cox proportional hazards regression was used to model relative risks (RR) and 95% confidence intervals (95% CI) for breast cancer across categories of dietary carbohydrate, glycemic index (GI), glycemic load (GL), as well as insulin load and insulin index scores. Adolescent or early adult intakes of GI or GL were not associated with risk of breast cancer. Comparing women in the highest versus lowest quintile, the multivariable-adjusted RRs were 1.14 (0.95-1.38) for adolescent GI scores and 1.03 (0.91-1.16) for early adulthood GI scores. We also did not observe associations with insulin index and insulin load scores in adolescence or early adulthood and breast cancer risk. We found that diets high in GI, GL, insulin index, and insulin load during adolescence or early adulthood were not associated with an increased risk of breast cancer in this cohort study. Diets with a high glucose or insulin response in adolescence or early adulthood were not significant predictors of breast cancer incidence.

Association between dietary carbohydrate intake and dietary glycemic index and risk of age-related cataract: a meta-analysis.

To assess the association of dietary carbohydrate intake and dietary glycemic index (GI), and risk of age-related cataract (ARC), and quantitatively estimate their dose-response relationships. We searched Medline, the Cochrane Library, Excerpta Medica database (EMBASE), Institute for Scientific Information (ISI) Science Citation Index, ISI Web of Knowledge, and China National Knowledge Infrastructure (CNKI) databases before October 2013. Two authors independently extracted data and assessed study quality. The random-effect model was used to calculate the pooled odds ratios (ORs). Dose-response analyses, subgroup analyses based on ARC subtypes, heterogeneity, and publication bias assessment were also carried out. Seven studies were included in our meta-analysis. The pooled ORs of ARC for the highest versus the lowest category of carbohydrate intake and GI were 1.18 (95% confidence interval [CI]: 1.01-1.38) and 1.15 (95% CI: 1.00-1.32), respectively. Further subgroup analyses based on ARC subtypes suggested a marginally significant association between higher carbohydrate intake and cortical cataract risk (OR: 1.37, 95% CI: 0.99-1.90), and a statistically significant association between higher GI and nuclear cataract risk (OR: 1.23, 95% CI: 1.03-1.46). In addition, a significant dose-response relationship was observed between carbohydrate intake and the risk of cortical cataract. Our results indicate that higher dietary carbohydrate quantity and GI may be associated with the risk of cortical and nuclear cataract, respectively. The results should be interpreted cautiously and more studies are warranted to clarify this issue.

Glycemic index, glycemic load, dietary carbohydrate, and dietary fiber intake and risk of liver and biliary tract cancers in Western Europeans

The type and quantity of dietary carbohydrate as quantified by glycemic index (GI) and glycemic load (GL), and dietary fiber may influence the risk of liver and biliary tract cancers, but convincing evidence is lacking. The association between dietary GI/GL and carbohydrate intake with hepatocellular carcinoma (HCC; N = 191), intrahepatic bile duct (IBD; N = 66), and biliary tract (N = 236) cancer risk was investigated in 477 206 participants of the European Prospective Investigation into Cancer and Nutrition cohort. Dietary intake was assessed by country-specific, validated dietary questionnaires. Hazard ratios and 95% confidence intervals were estimated from proportional hazard models. HBV/HCV status was measured in a nested case-control subset. Higher dietary GI, GL, or increased intake of total carbohydrate was not associated with liver or biliary tract cancer risk. For HCC, divergent risk estimates were observed for total sugar = 1.43 (1.17-1.74) per 50 g/day, total starch = 0.70 (0.55-0.90) per 50 g/day, and total dietary fiber = 0.70 (0.52-0.93) per 10 g/day. The findings for dietary fiber were confirmed among HBV/HCV-free participants [0.48 (0.23-1.01)]. Similar associations were observed for IBD [dietary fiber = 0.59 (0.37-0.99) per 10 g/day], but not biliary tract cancer. Findings suggest that higher consumption of dietary fiber and lower consumption of total sugars are associated with lower HCC risk. In addition, high dietary fiber intake could be associated with lower IBD cancer risk.

Abstract MP064: Dietary Contributors to Glycemic load in the REasons for Geographic and Racial Differences in Stroke (REGARDS) Study

Glycemic load (GL) is a measure that incorporates both the quality (i.e., glycemic index) and quantity of dietary carbohydrate and is a measure of the overall glycemic impact of the diet. In observational studies, high-GL diets have been associated with a greater prevalence of multiple coronary heart disease risk factors, including type 2 diabetes, overweight/obesity, dyslipidemia, inflammation, and abnormal blood clotting. To begin to develop interventions to reduce dietary GL, it is necessary to identify the major contributors to GL at the population level. We studied contributors to GL in 21,636 participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study (7074 white men, 2472 black men, 7287 white women, and 4803 black women) whose mean (SD) age was 64.9 (9.3) years at baseline (2003-2007). Mean daily GL, as well as individual carbohydrate food and food group contributors to GL, were determined for each participant using intake data from the Block 1998 semi-quantitative food frequency questionnaire administered at baseline. Mean (SD) daily GL was 107.1 (44.1), 115.0 (53.8), 89.9 (40.6), and 100.0 (49.6) g/d in white men, black men, white women, and black women, respectively. Sugar-sweetened beverages was the main carbohydrate food group contributing to GL in both black men and women and were important contributors to GL in white men and women (Figure). Regular soft drinks in particular were the leading individual carbohydrate contributor to GL in black men (4.0 median % of daily GL). The main carbohydrate food group contributing to GL in both white men and women was breads. Dark breads were the leading individual carbohydrate contributors to GL in white men, white women, and black women (2.7, 3.2, and 2.4 median % of daily GL, respectively). Sugar-sweetened beverages were a major contributor to dietary GL in this sample of US adults, especially in blacks. Decreasing the consumption of these beverages should be considered in future interventions to reduce dietary GL.

The Influence of Dietary Carbohydrate Content on Glycaemia in Patients with Glucokinase Maturity-Onset Diabetes of the Young

Mutations in the glucokinase (GCK) gene result in maturity-onset diabetes of the young (MODY). Pharmacotherapy is not effective in GCK MODY. Thus, nutritional intervention seems to be the only therapeutic option. This study evaluated the effect of the quantity of dietary carbohydrate on glucose levels in 10 GCK mutation carriers: seven with MODY and three with prediabetes. All patients were exposed to high-carbohydrate diets for 2 days and then switched to low-carbohydrate diets (60% versus 25% of the daily calorie intake) for another 2 days, after a 1-day washout. Glucose levels were assessed by continuous blood glucose monitoring. In patients with GCK MODY on high-carbohydrate diets, glucose levels were significantly higher, and more hyperglycaemic episodes occurred, compared with patients on low-carbohydrate diets. This short-term observational study suggested that diets with a modestly limited carbohydrate content may improve glycaemic control in patients with GCK MODY.

Influence of two breakfast meals differing in glycemic load on satiety, hunger, and energy intake in preschool children

BackgroundGlycemic load (GL) is the product of glycemic index of a food and amount of available carbohydrate in that food divided by 100. GL represents quality and quantity of dietary carbohydrate. Little is known about the role of GL in hunger, satiety, and food intake in preschool children. The aim of this study was to investigate the effect of two breakfast meals differing in GL on hunger, satiety, and subsequent food intake at lunch in preschool children aged 4-6 y.MethodsTwenty three subjects consumed low-GL (LGL) and high-GL (HGL) breakfast meals according to a randomized crossover design followed by an ad libitum lunch 4 h after consumption of breakfast. Children were asked to consume meals until they are full. Each treatment was repeated twice in non-consecutive days and data were averaged.ResultsChildren in LGL group consumed significantly lower amounts of GL, total carbohydrate, energy, energy density, and dietary fiber and higher amounts of protein and fat at the breakfast compared to those in HGL group. Prior to lunch, children were hungrier in the HGL intervention group compared to the LGL intervention group (P < 0.03). However, no significant difference was observed between LGL and HGL intervention groups in the amount of food and energy consumed during lunch.ConclusionsDecreased hunger in children prior to lunch in LGL group is likely due to higher protein and fat content of LGL breakfast. Diets that are low in GL can be recommended as part of healthy diet for preschool children.

A prospective study of dietary carbohydrate quantity and quality in relation to risk of ovulatory infertility

To evaluate whether the amount or quality of carbohydrate in diet is associated with ovulatory infertility. In total, 18,555 married, premenopausal women without a history of infertility were followed as they attempted a pregnancy or became pregnant during an 8-year period. Diet was assessed two times during follow-up using a validated food-frequency questionnaire and prospectively related to the incidence of infertility due ovulatory disorder. During follow-up, 438 women reported ovulatory infertility. Total carbohydrate intake and dietary glycemic load were positively related to ovulatory infertility in analyses adjusted for age, body mass index, smoking, parity, physical activity, recency of contraception, total energy intake, protein intake and other dietary variables. The multivariable-adjusted risk ratio (RR) (95% confidence interval (CI)) of ovulatory infertility comparing the highest-to-lowest quintile of total carbohydrate intake was 1.91 (1.27-3.02). The corresponding RR (95% CI) for dietary glycemic load was 1.92 (1.26-2.92). Dietary glycemic index was positively related to ovulatory infertility only among nulliparous women. Intakes of fiber from different sources were unrelated to ovulatory infertility risk. The amount and quality of carbohydrate in diet may be important determinants of ovulation and fertility in healthy women.

Interactions and competition within the microbial community of the human colon: links between diet and health

The microbiota of the human intestinal tract play an important role in health, in particular by mediating many of the effects of diet upon gut health. Surveys of 16S rRNA sequence diversity in the human colon have emphasized the low proportion of sequences that match cultured bacterial species. This may reflect limited recent effort on cultivation rather than inherent unculturability, however, as anaerobic isolation methods can apparently recover a wide range of the diversity found. A combination of information from representative cultures, molecular tools for enumeration and tracking of bacterial metabolites offers the most powerful route to understanding the roles played by different groups of bacteria in the gut ecosystem. Progress is being made for example in defining key functional groups including primary colonizers of insoluble dietary substrates, and major contributors to metabolites such as butyrate that influence the health of the gut mucosa. There is increasing evidence that bacterial populations in the large intestine respond to changes in diet, in particular to the type and quantity of dietary carbohydrate. A general consequence of increased carbohydrate consumption is to reduce the pH of the gut lumen, which is likely to play a major role in determining bacterial metabolism and competition. Oligosaccharides used as dietary prebiotics must inevitably have complex effects upon the bacterial community that include non-target organisms and the consequences of metabolic cross-feeding and changes in the gut environment.

Dietary carbohydrate intake and glycemic index in relation to cortical and nuclear lens opacities in the Age-Related Eye Disease Study

Little is known about the association between dietary carbohydrates and cataract in nondiabetic persons. The aim was to test whether recent dietary carbohydrate intakes or glycemic index (GI; a measure of carbohydrate intake quality) was associated with the presence of cortical or nuclear opacities. A modified Block food-frequency questionnaire was used to obtain dietary information from 3377 participants (aged 60-80 y; 56% were women) in the Age-Related Eye Disease Study (AREDS). Lens status was evaluated by using the AREDS System for Classifying Cataracts. Associations were examined for eyes with only a single, or pure, type of lens opacity by using the generalized estimating approach to logistic regression to account for the lack of independence between the eyes of a person. For participants in the highest quartile, dietary GI was associated with a higher prevalence of all pure nuclear opacities [grade >2; odds ratio (OR): 1.29; 95% CI: 1.04, 1.59; P for trend = 0.02] and moderate nuclear opacities (grade > or =4; OR: 1.43; 95% CI: 0.96, 2.14; P for trend = 0.052). The OR in a comparison of the highest with the lowest quartile of intake was 1.27 (95% CI: 0.99, 1.63; P for trend = 0.09) for cortical opacities of any severity (>0% of area opaque), and the OR increased somewhat for moderate cortical opacities (>5% of area opaque; OR: 1.71; 95% CI: 1.00, 2.95; P for trend = 0.056). Results from the cross-sectional analysis of AREDS baseline data suggest that dietary glycemic quality and dietary carbohydrate quantity may be associated with prevalent nuclear and cortical opacities, respectively.