High Glycemic Index Diet Research Articles

Identifying maternal nutritional risk factors associated with fetal macrosomia in Nigeria

Objective: To find out if maternal nutritional habits are associated with the birth of macrosomic babies in Nigeria Design: This was a cross-sectional retrospective study of the nutritional habits of mothers of macrosomic babies and mothers of normal (non-macrosomic) babies attending a post natal clinic in Nigeria Setting: This study was carried out in St Philomena’s Hospital, Benin City, Nigeria, a maternity hospital, which has a large clientele because of its accessibility and affordability. Participants: Seventy five (75) mothers of macrosomic babies and 93 mothers of normal (non-macrosomic) babies Results: There was a significant difference between the frequencies at which mothers of macrosomic and normal babies ingested similar qualitative amounts of the staple high glycemic index diets. There was also a significant difference between the frequencies at which mothers of macrosomic and normal babies ingested similar qualitative amounts of low glycemic index diet used in this study. Most of the mothers of macrosomic babies indulged in soft drinks at frequencies, which were significantly different from the frequencies at which mothers of normal babies indulged in them. There was however no significant difference between the frequencies at which mothers of macrosomic and normal babies indulged in cocoa drinks. There was also a significant difference between the usage of vegetables by mothers of macrosomic and normal babies. Conclusion: The dietary factors that predispose to fetal macrosomia are frequent ingestion of high glycemic index diets and soft drinks and the avoidance of dietary fibers.

Dietary carbohydrate intake, glycaemic index, glycaemic load and digestive system cancers: an updated dose-response meta-analysis.

Several studies analysed the associations between dietary carbohydrate intake, glycaemic index (GI) and glycaemic load (GL) and digestive system cancers; however, the results remain controversial. This study was to perform a meta-analysis evaluating the quantitative and dose-response associations between carbohydrate intake, GI and GL, and risk of digestive system cancers. We searched medical and biological databases up to June 2018 and identified twenty-six cohort studies and eighteen case-control studies. Meta-analytic fixed or random effects models were applied to process data. We also performed dose-response analysis, meta-regression and subgroup analyses. We found that high levels of GI were significantly associated with the risk of digestive system cancers at the highest compared with the lowest categories from cohort studies (summary relative risk (RR)=1·10, 95 % CI 1·05, 1·15). Similar effects were observed from case-control studies of the comparison between the extreme categories, but the difference did not reach statistical significance (summary OR=1·28, 95 % CI 0·97, 1·69). We also observed significant dose-response association between GI and digestive system cancers, with every 10-unit increase in GI (summary RR=1·003; 95 % CI 1·000, 1·012 for cohort studies; summary OR=1·09; 95 % CI 1·06, 1·11 for case-control studies). In addition, both cohort studies and case-control studies indicated that neither dietary carbohydrate intake nor GL bore any statistical relationship to digestive system cancers from the results of the highest compared with the lowest categories analyses and dose-response analyses. The results suggest a moderate association between high-GI diets and the risk of digestive system cancers.

Association between dietary glycemic index and liver enzymes level among apparently healthy adults

ObjectiveThe previous studies have revealed that there is a link between dietary glycemic index and lipid profile in overweight and obesity. The aim of study was to investigate whether the glycemic index is associated with liver enzymes. MethodAnthropometric and biochemical parameters were measured in 265 participants. Dietary glycemic index (GI) was assessed by using a validated food-frequency questionnaire. With adjusting confounder variable, Binary logistic regression was also used to predict the relationship between liver enzymes and quartile of intake. ResultsThere was a significant difference between low and high GI diet for BMR (P = 0.01), FFM (P = 0.03), TG (P = 0.02), HDL (P = 0.002). The association between HDL and glycemic index remained significant after adjustment of sex and age (P = 0.03). Using the regression model following adjustment revealed that for each 1% increase in the degree of the GI, there was 11% elevation in liver enzyme abnormalities. In both groups of men and women, enzyme abnormalities positively correlated with GI, while only men showed remarkable correlation in all models (crude model: β = 0.07, OR = 1.07, CI = 0.98to 1.16). Additionally, an increase in the degree of GI caused an elevation in enzyme abnormalities by 7%. With adjusting sex, age, BMI, and Physical activity, a significance correlation was found between GI and Enzyme abnormalities (p-value = 0.03, OR = 1.115). ConclusionOur study indicated that high glycemic index diet led to the elevated levels of the liver enzymes, while being significant only in men.

Anti-TNF-α Agent Tamarind Kunitz Trypsin Inhibitor Improves Lipid Profile of Wistar Rats Presenting Dyslipidemia and Diet-induced Obesity Regardless of PPAR-γ Induction.

The increasing prevalence of obesity and, consequently, chronic inflammation and its complications has increased the search for new treatment methods. The effect of the purified tamarind seed trypsin inhibitor (TTIp) on metabolic alterations in Wistar rats with obesity and dyslipidemia was evaluated. Three groups of animals with obesity and dyslipidemia were formed, consuming a high glycemic index and glycemic load (HGLI) diet, for 10 days: Obese/HGLI diet; Obese/standard diet; Obese/HGLI diet + TTIp (730 μg/kg); and one eutrophic group of animals was fed a standard diet. Rats were evaluated daily for food intake and weight gain. On the 11th day, animals were anesthetized and sacrificed for blood and visceral adipose tissue collection. TTIp treated animals presented significantly lower food intake than the untreated group (p = 0.0065), TG (76.20 ± 18.73 mg/dL) and VLDL-C (15.24 ± 3.75 mg/dL). Plasma concentrations and TNF-α mRNA expression in visceral adipose tissue also decreased in obese animals treated with TTIp (p < 0.05 and p = 0.025, respectively) with a negative immunostaining. We conclude that TTIp presented anti-TNF-α activity and an improved lipid profile of Wistar rats with dyslipidemia and obesity induced by a high glycemic index and load diet regardless of PPAR-γ induction.

A Short Study Exploring the Effect of the Glycaemic Index of the Diet on Energy intake and Salivary Steroid Hormones.

Background: The glycaemic index or load (GI or GL) is a concept for ranking carbohydrate-rich foods based on the postprandial blood glucose response compared with a reference food (glucose). Due to the limited research investigating the effect of the GI or GL of the diet on salivary steroidal hormones, this explorative short study was conducted. Methods: 12 female participants consumed a low GI and a high GI diet for three days each, followed by a washout period between each intervention. Saliva was collected at baseline, and following the low or high GI diets. Cortisol and testosterone concentrations were measured by enzyme-linked immuno-sorbent assay (ELISA). Results: GI and GL were significantly different between the low and high GI diets (p < 0.001). There was a small but significant increase in salivary cortisol after the high GI diet (7.38 to 10.93 ng/mL, p = 0.036). No effect was observed after the low GI diet. Higher levels of testosterone were produced after the low GI diet (83.7 to 125.9 pg/mL, p = 0.002), and no effect was found after the high GI diet. The total intake of calories consumed on the low GI diet was significantly lower compared to the high GI diet (p = 0.019). Conclusions: A low GI diet was associated with a small but significant increase in salivary testosterone, while a high GI diet increased cortisol levels. Altering the GI of the diet may influence overall energy intake and the health and wellbeing of female volunteers.

Exercise-induced improvements in glucose effectiveness areblunted by a high glycemic diet in adults with prediabetes.

Glucose effectiveness (GE) refers to the ability of glucose to influence its own metabolism through insulin-independent mechanisms. Diminished GE is a predictor of progression to type 2 diabetes. Exercise training improves GE, however, little is known about how dietary interventions, such as manipulating the glycemic index of diets, interact with exercise-induced improvements in GE in at-risk populations. We enrolled 33 adults with obesity and pre-diabetes (17 males, 65.7±4.3 years, 34.9±4.2kgm-2) into a 12-week exercise training program (1 hday-1 and 5 dayweek-1 at ~85% of maximum heart rate) while being randomized to concurrently receive either a low (EX-LOG: 40±0.3au) or high (EX-HIG: 80±0.6au) glycemic index diet. A 75-g oral-glucose-tolerance test (OGTT) was performed before and after the intervention and GE was calculated using the Nagasaka equation. Insulin resistance was estimated using a hyperinsulinemic-euglycemic clamp and cardiorespiratory fitness using a VO2max test. Both EX-LOG and EX-HIG groups had similar improvements in weight (8.6 ± 5.1kg, P < 0.001), VO2max (6 ± 3.5mLkg-1min-1, P < 0.001) and clamp-measured peripheral insulin resistance (1.7 ± 0.9mgkg-1min-1, P < 0.001), relative to baseline data. GE in EX-LOG and EX-HIG was similar at baseline (1.9 ± 0.38 vs. 1.85 ± 0.3mgdL-1min-1, respectively; P > 0.05) and increased by ~ 20% post-intervention in the EX-LOG arm (∆GE: 0.07-0.57mgdL-1min-1, P < 0.05). Plasma free fatty acid (FFA) concentrations also decreased only in the EX-LOG arm (∆FFA: 0.13 ± 0.23mmolL-1, P<0.05). Our data suggest that a high glycemic index diet may suppress exercise-induced enhancement of GE, and this may be mediated through plasma FFAs.

Vulnerability of Human Erythrocytes to Persistent High Glycemic Index Diets: Implications for Ageing and Neurodegeneration: Possible Amelioration by Carnosine

It is proposed that excessive consumption of high carbohydrate and high glycemic index (GI) diets, typical of the socalled Western diet, converts human erythrocytes into systemic sources of methylglyoxal (MG) and glycated protein, including alpha-synuclein. This is due to activity-induced deamidation of asparagine residues in the glycolytic enzyme triosephosphate isomerase (TPI), which can result in loss of enzyme activity and accumulation of the MG precursor dihydroxyacetone-phosphate. Under such circumstances, erythrocytic MG could provoke protein glycation in the tissues, including the brain, and may be responsible for much age-associated macromolecular modification. The naturally-occurring and pluripotent dipeptide carnosine (beta-alanyl-L-histidine) is enriched in erythrocytes (10-fold compared to sera). Carnosine could help to ameliorate MG generation and reactivity, due to its ability to (i) partially inhibit glycolysis and suppress MG generation and (ii) prevent MG-induced protein glycation, It is concluded that persistent consumption of high GI diets should be avoided, and carnosine, administered orally or intra-nasally to enhance access to the brain, could be explored with respect to age-related conditions including type-2 diabetes and neurodegeneration.

Circulating MicroRNAs in Overweight and Obese Patients

MicroRNAs, short noncoding RNA sequences, regulate several biological processes and seem also regulate insulin signaling, immune-mediated inflammation, adipokine expression, adipogenesis, lipid metabolism, and food intake. miRNAs may have a role in molecular mechanisms linked to cellular pathways of some diseases, as viral infections, cancer, diabetes, obesity and cardiovascular disease. The recent discovery of circulating miRNAs (c-miRNAs) easily detectable and measurable in plasma and other body fluids, led to the hypothesis of their potential role as disease indicators. It has been shown that altered levels of several c-miRNAs are linked to overweight, obesity and their complications. Different levels of some c-miRNAs were found significantly associated with weight gain, but most of the data concern comorbidities and complications of obesity as insulin resistance, pre-diabetes, diabetes, dyslipidemia, adipogenesis dysregulation and inflammatory processes. Moreover, several evidences were obtained in obese children, in newborns and in maternal pre-gestational and gestational obesity. In particular the expression of some c-miRNAs differs in infants born to obese women compared with those born to lean women and these biomarkers might be useful in predicting future risk of obesity in children. At last, down-regulation of different c-miRNAs was observed in overweight/obese subjects after low or high glycemic index diet and after low-fat diet; c-miRNAs might also be potential novel biomarkers for the benefits of bariatric surgery and the effects of mild exercise. A potential role of c-miRNAs detection as diagnostic, prognostic and therapeutic biomarkers in overweight and obese patients is supported by scientific evidence but there are several limits: number, duration and sample size of clinical studies are small; source of cmiRNAs, extraction procedures, quantities of blood samples and methods of analysis were promiscuous and not well standardized; high costs required for c-miRNAs detection. Reproducible and well standardized methods as well as lowcost and wide availability assays to detect c-miRNAs with high sensitivity/specificity and large, long-term and randomized controlled clinical studies are need to determine whether c-miRNAs can play a role as biomarkers for management of overweight and obesity in daily clinical practice.

Dietary glycaemic index and cognitive function: prospective associations in adults of the 1946 British birth cohort.

Evidence suggests that the rate of glucose release following consumption of carbohydrate-containing foods, defined as the glycaemic index (GI), is inversely associated with cognitive function. To date, most of the evidence stems from either single-meal studies or highly heterogeneous cohort studies. We aimed to study the prospective associations of diet GI at age 53 years with outcomes of verbal memory and letter search tests at age 69 years and rate of decline between 53 and 69 years. Longitudinal population-based birth cohort study. MRC National Survey for Health and Development. Cohort members (n 1252). Using multivariable linear and logistic regression, adjusted for potential confounders, associations of higher-GI diet with lower verbal memory, lower letter search speed and lower number of hits in a letter search test were attenuated after adjustments for cognitive ability at age 15 years, educational attainment, further training and occupational social class. No association was observed between diet GI at 53 years and letter search accuracy or speed-accuracy trade-off at 69 years, or between diet GI at 53 years and rate of decline between 53 and 69 years in any cognitive measure. Diet GI does not appear to predict cognitive function or decline, which was mainly explained by childhood cognitive ability, education and occupational social class. Our findings confirm the need for further research on the association between diet and cognition from a life-course perspective.

Association between Dietary Glycemic Index and Excess Weight in Pregnant Women in the First Trimester of Pregnancy.

To assess the association between dietary glycemic index (GI) and excess weight in pregnant women in the first trimester of pregnancy. A cross-sectional study in a sample of 217 pregnant women was conducted at the maternal-fetal outpatient clinic of the Hospital Geral de Fortaleza, Fortaleza, state of Ceará, Brazil, for routine ultrasound examinations in the period between 11 and 13 weeks + 6 days of gestation. Weight and height were measured and the gestational body mass index (BMI) was calculated. The women were questioned about their usual body weight prior to the gestation, considering the prepregnancy weight. The dietary GI and the glycemic load (GL) of their diets were calculated and split into tertiles. Analysis of variance (ANOVA) or Kruskal-Walls and chi-squared (χ2) statistical tests were employed. A crude logistic regression model and a model adjusted for confounding variables known to influence biological outcomes were constructed. A p-value < 0.05 was considered significant for all tests employed. The sample group presented a high percentage of prepregnancy and gestational overweight (39.7% and 40.1%, respectively). In the tertile with the higher GI value, there was a lower dietary intake of total fibers (p = 0.005) and of soluble fibers (p = 0.008). In the third tertile, the dietary GI was associated with overweight in pregnant women in the first trimester of gestation, both in the crude model and in the model adjusted for age, total energy intake, and saturated fatty acids. However, this association was not observed in relation to the GL. A high dietary GI was associated with excess weight in women in the first trimester of pregnancy.

Glycaemic Index of Maternal Dietary Carbohydrate Differentially Alters Fto and Lep Expression in Offspring in C57BL/6 Mice.

Maternal diet and gestational hyperglycaemia have implications for offspring health. Leptin (LEP) and fat mass and obesity-associated (FTO) alleles are known to influence body fat mass in humans, potentially via effects on appetite. We hypothesized that expression of Fto, Lep, and other appetite-related genes (Argp, Npy, Pomc, Cart, Lepr) in the offspring of female mice are influenced by the glycaemic index (GI) of carbohydrates in the maternal diet. C57BL/6 mice were randomly assigned to low or high GI diets and mated with chow-fed males at eight weeks of age. Male pups were weaned at four weeks and randomly divided into two groups, one group following their mother’s diet (LL and HH), and one following the standard chow diet (LC and HC) to 20 weeks. Fto expression was 3.8-fold higher in the placenta of mothers fed the high GI diet (p = 0.0001) and 2.5-fold higher in the hypothalamus of 20-week old offspring fed the high GI (HH vs. LL, p < 0.0001). By contrast, leptin gene (Lep) expression in visceral adipose tissue was 4.4-fold higher in four-week old offspring of low GI mothers (LC vs. HC, p < 0.0001) and 3.3-fold higher in visceral adipose tissue of 20-week old animals (LL vs. HH, p < 0.0001). Plasma ghrelin and leptin levels, and hypothalamic appetite genes were also differentially regulated by maternal and offspring diet. These findings provide the first evidence in an animal model that maternal high GI dietary carbohydrates that are digested and absorbed faster may contribute to programming of appetite in offspring.

High fructose consumption with a high-protein meal is associated with decreased glycemia and increased thermogenesis but reduced fat oxidation: A randomized controlled trial.

Fructose is often recommended due to its ability to lower glycemic response and its increased thermogenic effect. Additionally, proteins can reduce the glycemic response of carbohydrate-rich foods and have a high diet-induced thermogenesis (DIT). The aim of this study was to investigate whether the inclusion of fructose in a high-protein meal would demonstrate metabolic advantages. Nineteen Asian women (body mass index 17-28 kg/m2) consumed a low-glycemic index (GI; fructose) or high GI (glucose), high-protein breakfast followed by a standardized lunch in a randomized crossover design. Simultaneously, 8-h continuous glucose monitoring provided incremental area under the curve (iAUC) and 4-h indirect calorimetry provided DIT and respiratory quotient (RQ). The low GI diet resulted in a lower glucose iAUC (135 ± 25 versus 212 ± 23 mmol/L, P < 0.05) following breakfast, but no second-meal effect after the standardized lunch (217 ± 37 versus 228 ± 27 mmol/L, P < 0.05) compared with the high GI diet. Furthermore, 4-h DIT was greater (40.6 ± 2.3 versus 34.9 ± 1.8 kcal, P < 0.05) and RQ was increased after the fructose high-protein breakfast (0.047 ± 0.009 versus 0.028 ± 0.009, P < 0.05) compared with the glucose meal. Fructose is an effective sweetener in reducing glycemia and increasing DIT in the presence of a high-protein diet. However, the reduced fat oxidation after high fructose consumption might present a risk for increased lipogenesis.

Role of diet and food intake in age-related macular degeneration: a systematic review.

A systematic literature review was conducted to evaluate the role of diet and food intake in age-related macular degeneration (AMD). Eighteen high-quality studies were identified. Adherence to a Mediterranean diet had decreased risk of AMD progression. An Oriental diet pattern had decreased association with AMD prevalence, whereas a Western diet pattern had increased association with AMD prevalence. High consumption of vegetables rich in carotenoids and fatty fish containing omega-3 fatty acids was beneficial for those at risk of AMD. Vegetable oils and animal fats containing omega-6 fatty acids, and red/processed meat should be consumed minimally to reduce the risk of AMD progression. High glycaemic index diets and alcohol consumption of greater than two drinks a day had increased association with AMD. As the quality of diet and food intake had a vital role in AMD, the provision of appropriate nutritional advice to those at risk of AMD is recommended.

Altering Glucose Variability with Low- or High-Glycemic–Index Diets in Adults with Prediabetes Does Not Affect Beta-Cell Function or Markers of Oxidative Stress

High glycemic variability has been associated with increased oxidative stress and β-cell dysfunction. To test whether changes in glycemic variability impact β-cell function and oxidative stress markers in adults with prediabetes, we conducted an RCT where we provided study subjects controlled diets varying in glycemic index (GI) to experimentally manipulate post-prandial glucose excursions. After 2 weeks on a control diet (mean GI= 55-58), subjects were randomized to 1 of 3 groups for 4 weeks: low (LGI &amp;lt;35) GI diet, high (HGI &amp;gt;70) GI diet plus the anti-oxidant N-acetylcysteine (HGI/NAC) 600 mg BID or HGI diet plus placebo (HGI/PLAC). Subjects underwent CGMS (iPro), fasting markers of oxidative stress (GSH/GSSG and TBARS) and an IVGTT at the end of each diet. Independent t-test was used to test the intervention effect on the change in disposition index (DI), a marker of β-cell function. Fifty-two subjects (26M/26F, age 53±10 y, BMI 32.1±6.2 kg/m2) with IFG and/or IGT completed the study (18 LGI, 17 HGI/NAC, 17 HGI/PLAC). The 3 groups did not differ by sex, age, BMI, A1c, fasting or 2 h glucose (ANOVA). On the control diet, DI was inversely correlated with CGMS mean daily glucose (r=-0.33, p=0.02) and daily SD glucose (r=-0.31, p=0.03) and the GSH/GSSG ratio (r=-0.35, p=0.01), but not TBARS (r=0.13, p=0.4). Compared to LGI, HGI/PLAC increased mean CGMS glucose (change -1.4±1.9 LGI vs. 4.6±2.4 HGI/PLAC mg/dl, p=0.05) and SD (change -2.6±1.3 vs. 5.0±2.2, p=0.005). Results did not differ between HGI/PLAC and HGI/NAC. There were no significant intervention effects on DI, TBARS or GSH/GSSG ratio. Changes in CGMS mean glucose and SD and oxidative stress markers did not correlate with changes in DI. In conclusion, GI diet-induced changes in glucose concentrations and variability did not impact β-cell function or oxidative stress markers. These results suggest that glucose variability may be a consequence of β-cell dysfunction rather than a cause. Disclosure K. Utzschneider: Consultant; Self; Novo Nordisk Inc.. T.N. Johnson: None. K. Breymeyer: None. M.L. Neuhouser: None.

Higher dietary glycemic index and glycemic load values increase the risk of osteoporotic fracture in the PREvención con DIeta MEDiterránea (PREDIMED)-Reus trial

High glucose and insulin concentrations seem to have a negative impact on bone health. However, the relation between the dietary glycemic index (DGI) and the dietary glycemic load (DGL), which has proved to be effective at modulating blood glucose concentrations after carbohydrate consumption, has yet to be explored in relation to bone health. The aim of the study was to examine the associations between the DGI or DGL and the risk of osteoporotic-related fractures in an elderly Mediterranean population. The study was conducted in 870 subjects aged 55-80 y at high cardiovascular disease risk participating in the PREvención con DIeta MEDiterránea (PREDIMED)-Reus study. The DGI and DGL were estimated from validated food-frequency questionnaires with the use of the international glycemic index and glycemic load values, with glucose as reference. Data on osteoporotic fractures were acquired from a systematic review of medical records. We used Cox proportional hazard models to assess the risk of osteoporotic fracture according to tertiles of average DGI and DGL. A total of 114 new cases of osteoporotic-related fractures were documented after a mean follow-up of 8.9 y. Participants in the highest tertile of DGI and DGL had a significantly higher risk of osteoporotic fractures than those in the lowest tertile after adjusting for potential confounders (HR: 1.80; 95% CI: 1.03, 3.15 and HR: 3.20; 95% CI: 1.25, 8.18, respectively). A high DGI and DGL are associated with a higher risk of osteoporosis-related fractures in an elderly Mediterranean population at high cardiovascular disease risk. This trial was registered at isrctn.com as ISRCTN35739639.

Changes in Plasma Metabolite Concentrations after a Low-Glycemic Index Diet Intervention.

To examine whether a low-glycemic index (LGI) diet improves a set of plasma metabolites related to different metabolic diseases, and comparison to a high-glycemic index (HGI) diet and a low-fat (LF) diet. A parallel, randomized trial with three intervention diets: an LGI diet, an HGI diet, and an LF diet. A total of 122 adult overweight and obese subjects were enrolled in the study for 6 months. Blood samples were collected at baseline and at the end of the intervention. The plasma metabolomic profile of 102 subjects was analyzed using three different approaches: GC/quadrupole-TOF, LC/quadrupole-TOF, and nuclear magnetic resonance. Both univariate and multivariate analysis were performed. Serine levels were significantly higher following the LGI diet compared to both the HGI and LF diets (q=0.002), whereas leucine (q=0.015) and valine (q=0.024) were lower in the LGI diet compared to the LF diet. A set of two sphingomyelins, two lysophosphatidylcholines, and six phosphatidylcholines were significantly modulated after the LGI diet compared to the HGI and LF diets (q<0.05). Significant correlations between changes in plasma amino acids and lipid species with changes in body weight, glucose, insulin, and some inflammatory markers are also reported. These results suggest that an LGI diet modulates certain circulating amino acids and lipid levels. These findings may explain the health benefits attributed to LGI diets in metabolic diseases such as type 2 diabetes.

A Low Glycemic Index and Glycemic Load Diet Decreases Insulin-like Growth Factor-1 among Adults with Moderate and Severe Acne: A Short-Duration, 2-Week Randomized Controlled Trial

BackgroundA high glycemic index (GI) and glycemic load (GL) diet may stimulate acne proliferative pathways by influencing biochemical factors associated with acne. However, few randomized controlled trials have examined this relationship, and this process is not completely understood. ObjectiveThis study examined changes in biochemical factors associated with acne among adults with moderate to severe acne after following a low GI and GL diet or usual eating plan for 2 weeks. DesignThis study utilized a parallel randomized controlled design to compare the effect of a low GI and GL diet to usual diet on biochemical factors associated with acne (glucose, insulin, insulin-like growth factor [IGF]-1, and insulin-like growth factor binding protein [IGFBP]-3) and insulin resistance after 2 weeks. ParticipantsSixty-six participants were randomly allocated to the low GI and GL diet (n=34) or usual eating plan (n=32) and included in the analyses. Main outcome measuresThe primary outcomes were biochemical factors of acne and insulin resistance with dietary intake as a secondary outcome. Statistical analysesIndependent sample t tests assessed changes in biochemical factors associated with acne, dietary intake, and body composition pre- and postintervention, comparing the two dietary interventions. ResultsIGF-1 concentrations decreased significantly among participants randomized to a low GI and GL diet between pre- and postintervention time points (preintervention=267.3±85.6 mg/mL, postintervention=244.5±78.7 ng/mL) (P=0.049). There were no differences in changes in glucose, insulin, or IGFBP-3 concentrations or insulin resistance between treatment groups after 2 weeks. Carbohydrate (P=0.019), available carbohydrate (P<0.001), percent energy from carbohydrate (P<0.001), GI (P<0.001), and GL (P<0.001) decreased significantly among participants following a low GI/GL diet between the pre- and postintervention time points. There were no differences in changes in body composition comparing groups. ConclusionsIn this study, a low GI and GL diet decreased IGF-1 concentrations, a well-established factor in acne pathogenesis. Further research of a longer duration should examine whether a low GI and GL diet would result in a clinically meaningful difference in IGF-1 concentrations leading to a reduction in acne. This trial was registered at clinicaltrials.gov as NCT02913001.

The Effect of Dietary Glycaemic Index on Glycaemia in Patients with Type 2 Diabetes: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

Background: The increasing prevalence of diabetes in the United Kingdom and worldwide calls for new approaches to its management, and diets with low glycaemic index have been proposed as a useful means for managing glucose response. However, there are conflicting reports and differences in the results of studies in terms of their effectiveness. Furthermore, the impact of low-glycaemic index diets and their long-term use in patients with type 2 diabetes remains unclear. Objectives: The objective of this study was to conduct a systematic review and meta-analysis of the effect of low-glycaemic index diets in patients with type 2 diabetes. Methods: Search methods: Randomised controlled studies were selected from a number of databases (EBSCOHost with links to Health Research databases, PubMed, and grey literature) based on the Population, Intervention, Comparator, Outcomes and Study designs (PICOS) framework. The search terms included synonyms and Medical Subject Headings (MeSH) and involved the use of Boolean operators (AND/OR) which allowed the combination of words and search terms. Selection criteria: As per the selection criteria, the following types of articles were selected: studies on randomised controlled trials, with year of publication between 2008 and 2018, including patients with type 2 diabetes. Thus, studies involving patients with gestational and type 1 diabetes were excluded, as were observational studies. Nine articles which met the inclusion criteria were selected for the systematic review, whereas only six articles which met the criteria were included in the meta-analysis. Data collection and analysis: Studies were evaluated for quality and risk of bias. In addition, heterogeneity, meta-analysis, and sensitivity tests of the extracted data were carried out using Review Manager 5.3 (Review Manager, 2014). Results: The findings of the systematic review showed that the low-glycaemic index (low-GI) diet resulted in a significant improvement (<0.05) in glycated haemoglobin (HbA1c) in two studies: low-GI diet Δ = −0.5% (95% CI, −0.61% to −0.39%) vs. high-cereal fibre diet Δ = −0.18% (95% CI, −0.29% to −0.07%); and low-GI legume diet Δ = −0.5% (95%, −0.6% to −0.4%) vs. high-wheat fibre diet Δ = −0.3% (95% Cl, −0.4 to −0.2%). There was a slight improvement in one study (low glycaemic response = 6.5% (6.3–7.1) vs. control = 6.6% (6.3–7.0) and no significant difference (p > 0.05) in four studies compared with the control diet. Four studies showed improvements in fasting blood glucose in low-GI diets compared to higher-GI diets or control: low-GI diet = 150.8 ± 8.7 vs. higher-GI diet = 157.8 ± 10.4 mg/dL, mean ± SD p = 0.43; low-GI diet = 127.7 vs. high-cereal fibre diet = 136.8 mg/dL, p = 0.02; low-GI diet = 6.5 (5.6–8.4) vs. standard diabetic diet = 6.7 (6.1–7.5) mmol/L, median and interquartile range p > 0.05; and low-GI diet = 7.3 ± 0.3 vs. conventional carbohydrate exchange diet = 7.7 ± 0.4 mmol/L, mean ± SEM (Standard Error of Mean) p < 0.05. The results of the meta-analysis and sensitivity tests demonstrated significant differences (p < 0.001 and p < 0.001, respectively) between the low-GI diet and the higher-GI diet or control diet in relation to glycated haemoglobin. Differences between the low-GI diet and higher-GI diet or control were significant (p < 0.05) with respect to the fasting blood glucose following meta-analysis. Conclusion: The low-GI diet is more effective in controlling glycated haemoglobin and fasting blood glucose compared with a higher-GI diet or control in patients with type 2 diabetes.

Effects of a Carob-Pod-Derived Sweetener on Glucose Metabolism.

Background: Patients with type 2 diabetes mellitus (T2DM) have a higher incidence of cardiovascular (CV) events. The ingestion of high-glycemic index (GI) diets, specially sweetened beverage consumption, has been associated with the development of T2DM and CV disease. Objective: We investigated the effects of the intake of a sweetened beverage, obtained from natural carbohydrates containing pinitol (PEB) compared to a sucrose-enriched beverage (SEB) in the context of impaired glucose tolerance (IGT) and diabetes. Methods: The study was divided in three different phases: (1) a discovery phase where the plasma proteomic profile was investigated by 2-DE (two-dimensional electrophoresis) followed by mass spectrometry (matrix-assisted laser desorption/ionization time-of-flight—MALDI-TOF/TOF) in healthy and IGT volunteers; (2) a verification phase where the potential mechanisms behind the observed protein changes were investigated in the discovery cohort and in an additional group of T2DM volunteers; and (3) the results were validated in a proof-of-concept interventional study in an animal model of diabetic rats with complementary methodologies. Results: Six weeks of pinitol-enriched beverage (PEB) intake induced a significant increase in two proteins involved in the insulin secretion pathway, insulin-like growth factor acid labile subunit (IGF1BP-ALS; 1.3-fold increase; P = 0.200) and complement C4A (1.83-fold increase; P = 0.007) in IGT subjects but not in healthy volunteers. Changes in C4A were also found in the serum samples of Zucker diabetic fatty (ZDF) rats after four weeks of PEB intake compared to basal levels (P = 0.042). In addition, an increased expression of the glucose transporter-2 (GLUT2) gene was observed in the jejunum (P = 0.003) of inositol-supplemented rats when compared to sucrose supplementation. This change was correlated with the observed change in C4A (P = 0.002). Conclusions: Our results suggest that the substitution of a common sugar source, such as sucrose, by a naturally-based, pinitol-enriched beverage induces changes in the insulin secretion pathway that could help to reduce blood glucose levels by protecting β-cells and by stimulating the insulin secretion pathway. This mechanism of action could have a relevant role in the prevention of insulin resistance and diabetes progression.

Physicochemical properties, structure and in vitro digestibility on complex of starch with lotus (Nelumbo nucifera Gaertn.) leaf flavonoids

Lotus leaf flavonoids (LLF) are a group of bioactive natural substances. In this study, the structure, thermal properties, rheology behaviors and in vitro digestibility of cooked LLF-starch complex were investigated. Differential scanning calorimetry (DSC) analysis showed the shift in gelatinization peak to a higher temperature and the decrease in gelatinization enthalpies in the complexes significantly. The short-term retrogradation was retarded either. The flow behaviors of starch pastes changed with adding LLF. Scanning electron microscope (SEM) images showed a less compact structure in LLF-starch complex and laser confocal scanning microscope (CLSM) images detected that LLF mostly distributed around starch granules, which further prove the binding between LLF and starch. Moreover, fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) elucidated LLF probably interacted with starch by non-covalent bond especially hydrogen bond. In addition, LLF-starch complex exhibited inhibitory effect on starch digestion compared to pregelatinized starch, and the reasonable content of LLF-starch complex was (0.7 g/100 g). Thus, LLF-starch complex can be potentially used as a functional additive for high resistant starch (RS) and low glycemic index (GI) diets.