Simple versus complex carbohydrates and health: A frequently neglected problem.

AIMS: For several decades, there has been a notion that dietary fat is made of different components (at least SAFA, MUFA, and PUFA) that exhibit different and sometimes contrasting effects when associated with health and diseases: coronary heart disease (CHD) and cardiovascular diseases (CVD) in general. A similar fact is not noticed in carbohydrates and their components considering that even some major recent studies on the issue did not segregate simple carbohydrates from complex carbohydrates. In this study, we aimed to stress this need. DATA SYNTHESIS: A small number of selected studies are presented and commented where segregation of simple from complex carbohydrates was either performed or disregarded to address the inconsistency of not disentangling them. CONCLUSIONS: If only total fats were considered in investigations where fat was studied, the present notion and attitude toward different roles of the various classes of fats, at least SAFA versus unsaturated (MUFA and PUFA) would be missing. Therefore, there is a need to disentangle simple from complex carbohydrates, and this should be systematically applied when addressing CHD or CVD mortality risks and their preventive measures.

Usual Dietary Intake of Resistant Starch in US Adults from NHANES 2015-2016.

BACKGROUND: Resistant starch (RS) confers many health benefits, mostly due to nonenzymatic human digestion and gut microbiota fermentation capacity. The usual intake of naturally occurring dietary RS in US adults is unclear. OBJECTIVES: This study estimated usual daily RS intake in grams per 1000 kcal in US adults by sex, age, and ethnic group, as well as the most frequent food category contributing to RS intake using data from the NHANES 2015-2016. METHODS: RS content of foods consumed was matched with Food and Nutrient Database for Dietary Studies food codes. The National Cancer Institute method was used to estimate adults' usual RS intake from 2 24-h dietary recalls. Day 1 RS contribution from food groups to overall RS intake was ranked for the total sample, across age-sex categories, and across ethnic groups. RESULTS: In total, 5139 US adults (48.4% male) had a mean daily usual intake of RS of 1.9 ± 0.0 g/(1000 kcal⋅d). Males and females had a similar intake of RS [2.0 ± 0.0 g compared with 1.9 ± 0.0 g/(1000 kcal⋅d)] with no differences between sexes within the same age category. When comparing ethnic groups within each age category, the non-Hispanic white males and females had significantly lower RS intake than all other ethnic groups [range: 1.7-1.8 compared with 2.1-2.3 g RS/(1000 kcal⋅d), respectively], with no differences among the other ethnic groups. French fries and other fried white potatoes, rice, and beans, peas, and legumes were the most frequently consumed food categories contributing to RS intake in all adults. CONCLUSIONS: US adults should improve the intake of natural RS food sources. Increasing RS intake will improve gastrointestinal health as a prebiotic and potentially increase insulin sensitivity with adequate consumption (e.g., ∼15 g/d).

Development of feed composition tables using a statistical screening procedure.

Millions of feed composition records generated annually by testing laboratories are valuable assets that can be used to benefit the animal nutrition community. However, it is challenging to manage, handle, and process feed composition data that originate from multiple sources, lack standardized feed names, and contain outliers. Efficient methods that consolidate and screen such data are needed to develop feed composition databases with accurate means and standard deviations (SD). Considering the interest of the animal science community in data management and the importance of feed composition tables for the animal industry, the objective was to develop a set of procedures to construct accurate feed composition tables from large data sets. A published statistical procedure, designed to screen feed composition data, was employed, modified, and programmed to operate using Python and SAS. The 2.76 million data received from 4 commercial feed testing laboratories were used to develop procedures and to construct tables summarizing feed composition. Briefly, feed names and nutrients across laboratories were standardized, and erroneous and duplicated records were removed. Histogram, univariate, and principal component analyses were used to identify and remove outliers having key nutrients outside of the mean ± 3.5 SD. Clustering procedures identified subgroups of feeds within a large data set. Aside from the clustering step that was programmed in Python to automatically execute in SAS, all steps were programmed and automatically conducted using Python followed by a manual evaluation of the resulting mean Pearson correlation matrices of clusters. The input data set contained 42, 94, 162, and 270 feeds from 4 laboratories and comprised 25 to 30 nutrients. The final database included 174 feeds and 1.48 million records. The developed procedures effectively classified by-products (e.g., distillers grains and solubles as low or high fat), forages (e.g., legume or grass-legume mixture by maturity), and oilseeds versus meal (e.g., soybeans as whole raw seeds vs. soybean meal expellers or solvent extracted) into distinct sub-populations. Results from these analyses suggest that the procedure can provide a robust tool to construct and update large feed data sets. This approach can also be used by commercial laboratories, feed manufacturers, animal producers, and other professionals to process feed composition data sets and update feed libraries.

Short communication: Supplementation of fructo-oligosaccharides does not improve insulin sensitivity in heavy veal calves fed different sources of carbohydrates.

Heavy veal calves (4-6 mo old) often develop problems with insulin sensitivity. This could lead to metabolic disorders and impaired animal growth performance. Studies in various animal species have shown that the supplementation of short-chain fructo-oligosaccharides (scFOS) can improve insulin sensitivity. We therefore studied the effects of scFOS supplementation on insulin sensitivity in heavy veal calves. Forty male Holstein-Friesian calves (BW = 190 ± 2.9 kg; age = 162 ± 1.4 d at the start of the trial) were fed either a control milk replacer (MR) diet or a diet in which one-third of the lactose was replaced by glucose, fructose, or glycerol for 10 wk prior to the start of the trial. At the start of the trial, calves were subjected to a frequently sampled intravenous glucose tolerance test to assess whole-body insulin sensitivity (muscle and hepatic insulin sensitivity). Calves within each dietary treatment group were ranked based on their insulin sensitivity value. Half of the calves received scFOS (12 mg/kg of BW) with the MR for 6 wk (supplementation was equally distributed over the insulin sensitivity range). Subsequently, a second frequently sampled intravenous glucose tolerance test was conducted to assess the effect of scFOS. In addition, fasting plasma levels of glucose, insulin, triglycerides, and cholesterol were determined to calculate the quantitative insulin sensitivity check index and triglyceride:high-density lipoprotein cholesterol ratio (fasting indicators of insulin sensitivity). Whole-body insulin sensitivity was low at the start of the trial and remained low in all groups [1.0 ± 0.1 and 0.8 ± 0.1 (mU/L)-1 · min-1 on average, respectively]. Supplementation of scFOS did not improve insulin sensitivity in any of the treatment groups. The quantitative insulin sensitivity check index and the triglyceride:high-density lipoprotein cholesterol ratio also did not differ between scFOS and non-scFOS calves and averaged 0.326 ± 0.003 and 0.088 ± 0.004, respectively, at the end of the trial. We conclude that scFOS supplementation does not improve insulin sensitivity in heavy veal calves regardless of the carbohydrate composition of the MR. This is in contrast to other animals (e.g., dogs and horses), where scFOS supplementation did improve insulin sensitivity. The absence of an effect of scFOS might be related to the dosage or to metabolic differences between ruminants and nonruminants. Increasing evidence indicates that dietary interventions in veal calves have little or no effect on insulin sensitivity, possibly because of low levels of insulin sensitivity.

Association between a dietary carbohydrate index and cardiovascular disease in the SUN (Seguimiento Universidad de Navarra) Project.

BACKGROUND AND AIMS: Beyond the quantity of carbohydrate intake, further research is needed to know the relevance of carbohydrate quality following operational indices. No previous longitudinal study has assessed the association between an index for quality of dietary carbohydrate intake and the risk of cardiovascular disease (CVD). Here, we examined the association between a carbohydrate quality index (CQI) and the risk of CVD. METHODS AND RESULTS: We used a validated semi-quantitative 136-item food-frequency questionnaire (FFQ) in a prospective follow-up study of 17,424 middle-aged adults from Spain. The CQI was defined by four criteria: dietary fiber intake, glycemic index, whole-grain/total-grain carbohydrate ratio, and solid/total carbohydrate ratio. We observed 129 incident cases of CVD during 10.1 y of median follow-up. An inverse association for CQI was found (hazard ratio = 0.44, 95% confidence interval (CI): 0.25-0.78 for the highest versus the lowest tertile, p for trend = 0.008). Participants in the highest tertile of the whole-grain/total-grain carbohydrate ratio had 47% lower risk of CVD (95% CI: 0.33-0.85, p for trend = 0.008). Participants with higher baseline CQI and higher baseline energy from carbohydrates had the lowest risk of CVD. CONCLUSION: In this Mediterranean cohort, a better quality of dietary carbohydrates measured by the CQI, showed a significant inverse association with the incidence of CVD. Specially, a higher proportion of carbohydrates from whole grains was strongly inversely associated with CVD. "Heart-healthy" diets should be focused not only on carbohydrate quantity but also on a multidimensional assessment of the type and quality of carbohydrates.

The Truth about Sugar.

Sugars are used by the industry to enhance the attractiveness of foods and drinks. These added sugars, or 'free sugars', are not easily identified in food or drink labels. Certain manufactured foods and drinks with 'safe' names, such as dried fruit and fruit juice, still contain free sugars and can be confusing. Guidance states that daily consumption of free sugars should be less than 10% of total energy intake (no more than 5% in the UK). However, it is found that both tooth decay and obesity are associated with consumption of free sugars in large quantities and at inappropriate times.

Invited review: Enteric methane in dairy cattle production: quantifying the opportunities and impact of reducing emissions.

Many opportunities exist to reduce enteric methane (CH4) and other greenhouse gas (GHG) emissions per unit of product from ruminant livestock. Research over the past century in genetics, animal health, microbiology, nutrition, and physiology has led to improvements in dairy production where intensively managed farms have GHG emissions as low as 1 kg of CO2 equivalents (CO2e)/kg of energy-corrected milk (ECM), compared with >7 kg of CO2 e/kg of ECM in extensive systems. The objectives of this review are to evaluate options that have been demonstrated to mitigate enteric CH4 emissions per unit of ECM (CH4/ECM) from dairy cattle on a quantitative basis and in a sustained manner and to integrate approaches in genetics, feeding and nutrition, physiology, and health to emphasize why herd productivity, not individual animal productivity, is important to environmental sustainability. A nutrition model based on carbohydrate digestion was used to evaluate the effect of feeding and nutrition strategies on CH4/ECM, and a meta-analysis was conducted to quantify the effects of lipid supplementation on CH4/ECM. A second model combining herd structure dynamics and production level was used to estimate the effect of genetic and management strategies that increase milk yield and reduce culling on CH4/ECM. Some of these approaches discussed require further research, but many could be implemented now. Past efforts in CH4 mitigation have largely focused on identifying and evaluating CH4 mitigation approaches based on nutrition, feeding, and modifications of rumen function. Nutrition and feeding approaches may be able to reduce CH4/ECM by 2.5 to 15%, whereas rumen modifiers have had very little success in terms of sustained CH4 reductions without compromising milk production. More significant reductions of 15 to 30% CH4/ECM can be achieved by combinations of genetic and management approaches, including improvements in heat abatement, disease and fertility management, performance-enhancing technologies, and facility design to increase feed efficiency and life-time productivity of individual animals and herds. Many of the approaches discussed are only partially additive, and all approaches to reducing enteric CH4 emissions should consider the economic impacts on farm profitability and the relationships between enteric CH4 and other GHG.

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.

Refined carbohydrate intake in relation to non-verbal intelligence among Tehrani schoolchildren.

OBJECTIVE: Nutrition has long been considered one of the most important environmental factors affecting human intelligence. Although carbohydrates are the most widely studied nutrient for their possible effects on cognition, limited data are available linking usual refined carbohydrate intake and intelligence. The present study was conducted to examine the relationship between long-term refined carbohydrate intake and non-verbal intelligence among schoolchildren. DESIGN: Cross-sectional study. SETTING: Tehran, Iran. SUBJECTS: In this cross-sectional study, 245 students aged 6-7 years were selected from 129 elementary schools in two western regions of Tehran. Anthropometric measurements were carried out. Non-verbal intelligence and refined carbohydrate consumption were determined using Raven's Standard Progressive Matrices test and a modified sixty-seven-item FFQ, respectively. Data about potential confounding variables were collected. Linear regression analysis was applied to examine the relationship between non-verbal intelligence scores and refined carbohydrate consumption. RESULTS: Individuals in top tertile of refined carbohydrate intake had lower mean non-verbal intelligence scores in the crude model (P < 0.038). This association remained significant after controlling for age, gender, birth date, birth order and breast-feeding pattern (P = 0.045). However, further adjustments for mother's age, mother's education, father's education, parental occupation and BMI made the association statistically non-significant. We found a significant inverse association between refined carbohydrate consumption and non-verbal intelligence scores in regression models (ß = -11.359, P < 0.001). This relationship remained significant in multivariate analysis after controlling for potential confounders (ß = -8.495, P = 0.038). CONCLUSIONS: The study provides evidence indicating an inverse relationship between refined carbohydrate consumption and non-verbal intelligence among Tehrani children aged 6-7 years. Prospective studies are needed to confirm our findings.

Diet and breast cancer.

Both diet and nutrition have been studied in relationship with breast cancer risk, as the great variation among different countries in breast cancer incidence could possibly be explained through the inflammatory and immune response, as well as antioxidant intake, among others. To date, no clear association with diet beyond overweight and weight gain has been found, except for alcohol consumption. Nonetheless, the small number of studies done in middle to low income countries where variability of food intake is wider, is beginning to show interesting results.

A glycaemic index compendium of non-western foods.

Current international tables published on the glycaemic index (GI) of foods represent valuable resources for researchers and clinicians. However, the vast majority of published GI values are of Western origin, notably European, Australian and North American. Since these tables focus on Western foods with minimal inclusion of other foods from non-Western countries, their application is of limited global use. The objective of this review is to provide the GI values for a variety of foods that are consumed in non-Western countries. Our review extends and expands on the current GI tables in an attempt to widen its application in many other regions of the world.

Glycemic impact as a property of foods is accurately measured by an available carbohydrate method that mimics the glycemic response.

The relative glycemic impact (RGI), the weight of glucose that would induce a glycemic response equivalent to that induced by a given amount of food, is preferably expressed for reference amounts of foods customarily consumed per eating occasion. But because customarily consumed portions of different foods deliver different glycemic carbohydrate doses, methods for determining their RGI need to allow for homeostatic responses to different glycemic carbohydrate loadings. We tested the accuracy of an in vitro method for measuring the RGI of customarily consumed portions that allows for homeostasis, using 24 foods. Glucose equivalents released during simulated gastrointestinal digestion were adjusted by the glycemic potency of contributing sugars to obtain cumulative glycemic glucose equivalents (GGE) and multiplied by food portion weight. Corresponding dose-dependent blood glucose clearance was calculated and subtracted from GGE, giving net GGE compared with time curves reminiscent of blood glucose response curves. RGI values (GGE content) for the food portions were obtained by comparing incremental areas under the curves for foods with that for a white bread reference of known GGE content. The correlation between in vivo values calculated from glycemic index values for the same foods and in vitro values was: in vivo GGE = 1.0 in vitro GGE - 0.5; R2 = 0.90. Bland-Altman methods comparison analysis showed close agreement: in vivo GGE = -0.055 in vitro GGE + 1.16; R2 = 0.027. The results suggest that a modified available carbohydrate determination can economically provide valid RGI values for consumer and industry use.

The influence of maternal glycaemia and dietary glycaemic index on pregnancy outcome in healthy mothers.

Infant birth weight has increased in Ireland in recent years along with levels of childhood overweight and obesity. The present article reviews the current literature on maternal glycaemia and the role of the dietary glycaemic index (GI) and its impact on pregnancy outcomes. It is known that maternal weight and weight gain significantly influence infant birth weight. Fetal macrosomia (birth weight >4000 g) is associated with an increased risk of perinatal trauma to both mother and infant. Furthermore, macrosomic infants have greater risk of being obese in childhood, adolescence and adulthood compared to normal-sized infants. There is evidence that there is a direct relationship between maternal blood glucose levels during pregnancy and fetal growth and size at birth, even when maternal blood glucose levels are within their normal range. Thus, maintaining blood glucose concentrations within normal parameters during pregnancy may reduce the incidence of fetal macrosomia. Maternal diet, and particularly its carbohydrate (CHO) type and content, influences maternal blood glucose concentrations. However, different CHO foods produce different glycaemic responses. The GI was conceived by Jenkins in 1981 as a method for assessing the glycaemic responses of different CHO. Data from clinical studies in healthy pregnant women have documented that consuming a low-GI diet during pregnancy reduces peaks in postprandial glucose levels and normalises infant birth weight. Pregnancy is a physiological condition where the GI may be of particular relevance as glucose is the primary fuel for fetal growth.

Long-term effects on haemostatic variables of three ad libitum diets differing in type and amount of fat and carbohydrate: a 6-month randomised study in obese individuals.

Diet is important in the prevention of CVD, and it has been suggested that a diet high in MUFA is more cardioprotective than a low-fat diet. We hypothesised that the thrombotic risk profile is improved most favourably by a high-MUFA diet compared with a low-fat diet. This was tested in a parallel randomised intervention trial on overweight individuals (aged 28·2 (sd 4·6) years) randomly assigned to a diet providing a moderate amount of fat (35-45 % of energy; >20 % of fat as MUFA) (MUFA diet; n 39), to a low-fat (LF; 20-30 % of energy) diet (n 43), or to a control diet (35 % of energy as fat; n 24) for 6 months after a weight loss of about 10 %. Protein constituted 10-20 % of energy in all three diets. All foods were provided free of charge from a purpose-built supermarket. Fasting blood samples were collected before and after intervention and analysed for factor VII coagulant activity (FVII:c), fibrinogen, prothrombin fragment 1+2 (F1+2), D-dimer and plasminogen activator inhibitor (PAI). The fibrinogen concentration was significantly lowered by the LF diet, but not by the MUFA diet. Changes in fibrinogen differed significantly between diet groups. BMI and PAI concentration increased and D-dimer concentrations were reduced irrespective of the diets. No changes were observed for FVII:c and F1+2. Our findings suggest that in overweight subjects after weight loss the thrombotic risk profile is improved most favourably by the LF diet compared with the MUFA diet based on the reduction in fibrinogen concentrations.

Variations in compliance with starchy food recommendations and consumption of types of starchy foods according to sociodemographic and socioeconomic characteristics.

Nutritional recommendations call for balanced, diversified consumption of starchy foods and increased whole-grain food intake. Their efficiency may depend on sociodemographic and socioeconomic factors, for which little information is available. The aim of the present study was to investigate the relationship between sociodemographic and socioeconomic characteristics and starchy food consumption in a large general population of French adults. Dietary intake was assessed using at least six 24-h dietary records collected, during a 2-year period, from 4574 men and women aged 45-60 years who participated in the Supplémentation en VItamines Minéraux et AntioXydants cohort study in 1995-7. Compliance with the recommendation ( > or = 3 and < 6 servings/d), non-consumption of whole-grain products, variety and daily cost were compared across sociodemographic and socioeconomic categories using logistic regression and covariance analyses. About 55 % of subjects complied with the starchy food recommendation, with little variation across sociodemographic characteristics. Consumption of whole-grain products was less likely in men (P = 0.001), in subjects with a lower education level (P-trend = 0.01) and in those belonging to intermediate occupational categories (P = 0.02). The variety of starchy food intake increased with education level (P-trend = 0.0002) and was lowest for manual workers (P = 0.03). The proportion of daily food cost spent on starchy foods decreased with occupational category (P < 0.0001), and was higher in rural areas (P = 0.0004). The starchy food budget spent on potatoes decreased with the educational level (P-trend = 0.007), whereas it increased for rice and unsweetened breakfast cereals (P-trend = 0.001 for both). Public recommendations concerning starchy food variety and whole-grain intake should specifically target subjects with a lower education level and/or occupational category.

Association between glycemic index, glycemic load, and fructose with insulin resistance: the CDC of the Canary Islands study.

BACKGROUND: The involvement of carbohydrates in triggering insulin resistance (IR) remains a source of controversy. AIM OF THE STUDY: To study the relation between glycemic index (GI), glycemic load (GL), and fructose with insulin resistance in a predominantly rural population in the Canary Islands. METHODS: Cross-sectional study carried out in 668 nondiabetic people aged 18-75. IR was estimated with serum glucose and C-peptide (HOMA2-IR). Nutrient intakes were obtained from a validated food frequency questionnaire. ANOVA was used to analyze nutrient distribution across quartiles of HOMA2-IR. Four multivariate nutrient density models (dependent variable: log-transformed HOMA2-IR) which differed only in the kinds of carbohydrates included were tested (Model 1: carbohydrates; Model 2: GI and then GL; Model 3: free fructose, other simple sugars and starch; Model 4: total fructose, remaining sugars and starch). RESULTS: There was no association between GI and IR. There was a direct association between GL (P < 0.001), fructose (free [P = 0.001], total [P = 0.013]), energy intake (P < 0.001), fruit fiber (<0.001), and glucose (P = 0.003) with IR. There was an inverse association between cereal (P = 0.008) and vegetable fiber (P < 0.001) and IR. Multivariate models corroborated the association of carbohydrates, GL, fructose, vegetable fiber, and energy intake with IR. The association between GL and IR disappeared when Model 2 was adjusted by total fructose intake. CONCLUSIONS: There was a direct association between fructose intake and IR. There was no relationship between GI and IR. Although a direct association of GL with IR was detected, it was attributable to the consumption of fructose.

Production, structure, and bioactivity of polysaccharide isolated from Tremella fuciformis XY.

Tremella fuciformis polysaccharide (TFP) is an important bioactive substance in Tremella, that contributes to its use as medicine and food. In this study, a novel fungus Tremella fuciformis XY was isolated and introduced to produce macromolecule polysaccharides (TFPB). The fermentation conditions were optimized and results demonstrates that the initial pH, optimal temperature and liquid volume were 6.0, 26 °C and 80 mL in a 500 mL flask, respectively. The maximum yield of TFPB was 9.05 ± 0.05 g/L, which is 59.05% higher than the basic yield (5.69 ± 0.02 g/L). The TFPB, purified by DEAE column, had a molecular weight (Mw) of 1.14 × 103 kDa and consisted mainly of mannose, glucuronic acid, glucose, galactose, xylose, and rhamnose at a molar ratio of 3.5:1.2:2:1.6:1.4:3. The structure of TFPB was preliminarily investigated by methylation analysis, infrared spectroscopy, and nuclear magnetic resonance analysis. The main linkage types were identified as 1,4-xylp, 1,4-manp, 1-xylp, 1-manp, 1,4-glcp, and 1,3,4-galp. Moreover, the antioxidant assays showed that TFPB could scavenge reactive oxygen species and hydroxyl radicals.

Carbohydrate quality changes and concurrent changes in cardiovascular risk factors: a longitudinal analysis in the PREDIMED-Plus randomized trial.

BACKGROUND: Overall quality of dietary carbohydrate intake rather than total carbohydrate intake may determine the risk of cardiovascular disease (CVD). OBJECTIVE: We examined 6- and 12-mo changes in carbohydrate quality index (CQI) and concurrent changes in several CVD risk factors in a multicenter, randomized, primary-prevention trial (PREDIMED-Plus) based on an intensive weight-loss lifestyle intervention program. METHODS: Prospective analysis of 5373 overweight/obese Spanish adults (aged 55-75 y) with metabolic syndrome (MetS). Dietary intake information obtained from a validated 143-item semiquantitative food-frequency questionnaire was used to calculate 6- and 12-mo changes in CQI (categorized in quintiles), based on 4 criteria (total dietary fiber intake, glycemic index, whole grain/total grain ratio, and solid carbohydrate/total carbohydrate ratio). The outcomes were changes in intermediate markers of CVD. RESULTS: During the 12-mo follow-up, the majority of participants improved their CQI by increasing their consumption of fruits, vegetables, legumes, fish, and nuts and decreasing their consumption of refined cereals, added sugars, and sugar-sweetened beverages. After 6 mo, body weight, waist circumference (WC), systolic and diastolic blood pressure (BP), fasting blood glucose, glycated hemoglobin (HbA1c), triglyceride levels, triglycerides and glucose (TyG) index, and TyG-WC decreased across successive quintiles of improvement in the CQI. After 12 mo, improvements were additionally observed for HDL cholesterol and for the ratio of total to HDL cholesterol. Favorable improvements (expressed in common units of SD and 95% CI) for quintile 5 compared with quintile 1 of CQI change were observed for most risk factors, including TyG-WC (SD -0.20; 95% CI -0.26, -0.15), HbA1c (SD -0.16; 95% CI -0.23, -0.10), weight (SD -0.12; 95% CI -0.14, -0.09), systolic BP (SD -0.11; 95% CI -0.19, -0.02) and diastolic BP (SD -0.11; 95% CI -0.19, -0.04). CONCLUSIONS: Improvements in CQI were strongly associated with concurrent favorable CVD risk factor changes maintained over time in overweight/obese adults with MetS. This trial was registered as ISRCTN 89898870.

Dietary carbohydrate source alters gene expression profile of intestinal epithelium in mice.

High-sucrose consumption is associated with increased risk of human colon cancer. Our previous research indicated that high-sucrose diets (vs. cornstarch) promote intestinal epithelial cell proliferation and tumorigenesis as well as increase serum glucose and hepatic IGF-I mRNA levels in APC(Min) mice. To examine the role of functional pathways, in particular of IGF-I signaling, in sucrose-induced intestinal epithelial cell proliferation and tumorigenesis, we examined the effects of dietary carbohydrate source (sucrose vs. cornstarch) on gene expression in the intestinal epithelium using cDNA microarray and quantitative RT-PCR analysis. Dietary carbohydrate source significantly (P < 0.05) altered mRNA expression of 109 known genes in the small intestinal epithelium, including many involved in metabolic pathways. Consumption of high-sucrose diets altered expression levels of genes involved in cell adhesion, cell cycle control, and transduction signaling, consistent with increased risk of intestinal tumorigenesis. High-sucrose intake also affected expression of genes involved in IGF-I signaling, including upregulating IGF-II and downregulating IGFBP3, which supports our hypothesis that IGF-I signaling could play a role in intestinal epithelial cell proliferation and tumorigenesis promoted by high-sucrose consumption.

Gastrointestinal effects of low-digestible carbohydrates.

Low-digestible carbohydrates (LDCs) are carbohydrates that are incompletely or not absorbed in the small intestine but are at least partly fermented by bacteria in the large intestine. Fiber, resistant starch, and sugar alcohols are types of LDCs. Given potential health benefits (including a reduced caloric content, reduced or no effect on blood glucose levels, non-cariogenic effect) the prevalence of LDCs in processed foods is increasing. Many of the benefits of LDCs are related to the inability of human digestive enzymes to break down completely the carbohydrates into absorbable saccharides and the subsequent fermentation of unabsorbed carbohydrates in the colon. As a result, LDCs may affect laxation and cause gastrointestinal effects, including abdominal discomfort, flatus, and diarrhea, especially at higher or excessive intakes. Such responses, though transient, affect the perception of the well-being of consumers and their acceptance of food products containing LDCs. Current recommendations for fiber intake do not consider total LDC consumption nor recommend an upper limit for LDC intake based on potential gastrointestinal effects. Therefore, a review of published studies reporting gastrointestinal effects of LDCs was conducted. We included only studies published in refereed journals in English. Additionally, we excluded studies of subjects with incomplete or abnormal functioning gastrointestinal tracts or where antibiotics, stimulant laxatives, or other drugs affecting motility were included. Only in studies with a control period, either placebo treatment or no LDC treatment, were included. Studies must have included an acceptable measure of gastrointestinal effect. Sixty-eight studies and six review articles were evaluated. This review describes definitions, classifications, and mechanisms of LDCs, evaluates published human feeding studies of fifteen LDCs for associations between gastrointestinal effects and levels of LDC intake, and presents recommendations for LDC consumption and further research.