Food-based ingredients to modulate blood glucose

Regulator of G-Protein Signalling 9: A New Candidate Gene for Sweet Food Liking?

Genetics plays an important role in individual differences in food liking, which influences food choices and health. Sweet food liking is a complex trait and has been associated with increased body mass index (BMI) and related comorbidities. This genome-wide association study (GWAS) aimed to investigate the genetics of sweet food liking using two adult discovery cohorts (n = 1109, n = 373) and an independent replication cohort (n = 1073). In addition, we tested the association of our strongest result on parameters related to behaviour (food adventurousness (FA) and reward dependence (RD) and health status (BMI and blood glucose). The results demonstrate a novel strong association between the Regulator of G-Protein Signalling 9 (RGS9I) gene, strongest single nucleotide polymorphism (SNP) rs58931966 (p-value 7.05 × 10^-9 in the combined sample of discovery and replication), and sweet food liking, with the minor allele (A) being associated with a decreased sweet food liking. We also found that the A allele of the rs58931966 SNP was associated with decreased FA and RD, and increased BMI and blood glucose (p-values < 0.05). Differences were highlighted in sex-specific analysis on BMI and glucose. Our results highlight a novel genetic association with food liking and are indicative of genetic variation influencing the psychological-biological drivers of food preference. If confirmed in other studies, such genetic associations could allow a greater understanding of chronic disease management from both a habitual dietary intake and reward-related perspective.

A Novel Luminescent "Nanochip" as a Tandem Catalytic System for Chemiluminescent Detection of Sweat Glucose

Accurate sweat glucose detection is a promising alternative to invasive finger-prick blood tests, allowing for self-monitoring of blood glucose with good patient compliance. In this study, we have developed a tandem catalytic system, termed as a luminescent "nanochip" (LAON), which was composed of gold nanoparticles (AuNPs) and N-(aminobutyl)-N-(ethylisoluminol) (ABEI)-engineered oxygen-doped carbon nitride (O-g-C₃N₄), for chemiluminescent detection of sweat glucose. The LAON exhibits dual catalytic activity of glucose oxidase and peroxidase and can not only oxidize glucose to generate H₂O₂ but catalyze H₂O₂-mediated luminol chemiluminescence, resulting in sensitive detection of glucose. We identify that the LAON can precisely detect glucose with a detection limit of 0.1 μM, enabling us to measure glucose levels in different biological samples. Particularly, the LAON is capable of sensitively and accurately monitoring dynamic changes in sweat glucose during exercise. Therefore, the LAON provides an alternative approach to supersede invasive blood tests and may improve the management of diabetes mellitus.

Assessment of the glycaemic index, content of bioactive compounds, and their in vitro bioaccessibility in oat-buckwheat breads

This study addressed determinations of the glycaemic index (GI), antioxidant capacity (AC), and phenolics content (TPC) of oat, buckwheat, and mixed oat/buckwheat breads. The bioaccessibility of TPC and the AC of breads were studied after in vitro digestion. The lowest values of the GI were determined for oat bread, whereas breads with the highest content of buckwheat flour had the highest AC. The digestion of breads showed that most of the TPC were found in the soluble fraction, but the phenolic compounds were still present also in the insoluble fraction after digestion. It was concluded that the mixed oat-buckwheat breads may serve as products with a medium GI, as a source of TPC, and as products with a high AC. It should be noted that enzymatic digestion or fermentation by microbiota could potentially enhanced breads antioxidant activity during digestion in the gastrointestinal tract.

Mulberry leaf polyphenols attenuated postprandial glucose absorption via inhibition of disaccharidases activity and glucose transport in Caco-2 cells

The present study attempted to evaluate the mechanism of action and bioactivity of mulberry leaf polyphenols (MLPs) in type-2 diabetes prevention via inhibition of disaccharidase and glucose transport.

Enzyme-treated orange pomace alters acute glycemic response to orange juice

The goal of the present study was to determine the impact of the addition of enzyme-treated orange pomace to orange juice on postprandial glycemic response. Ten healthy subjects (aged 27.9 ± 7.7 years, body mass index 22.1 ± 1.1 kg m⁻²) participated in a randomized, 2-arm, cross-over clinical trial to test the glycemic response to 100% orange juice (OJ) or 100% orange juice with 5 g of enzyme-treated orange pomace fiber (OPF). Blood samples were collected and glucose and insulin concentrations were measured at fasting (0 min) and every 15 min for 2 h after consuming the study juice products. Analysis of the 2 h incremental area under the curve (iAUC_0–2h) indicated a significant reduction in blood glucose after ingesting the OPF juice compared to the OJ, p = 0.02. Peak glucose concentrations were also lowered after the OPF juice compared to the OJ, p < 0.05. No significant difference was observed in insulin responses between treatments, p > 0.05. Overall, this study demonstrated that adding 5 g of fiber from orange pomace into a serving of OJ attenuated the postprandial glucose response.

Free sugar content, in vitro starch digestibility and predicted glycemic index of ready-to-eat breakfast cereals commonly consumed in Turkey: An evaluation of nutritional quality

Breakfast cereal products are produced using the extrusion technique, which improves their digestion and absorption in the small intestine. However, this technique may cause an increase in the glycemic index of a food. Although high carbohydrate-rich foods are consumed in Turkey, there is not enough information about their GIs. The purpose of this study was to determine the free sugar content, in vitro starch digestibility, and predicted GI of different types of breakfast cereals commonly consumed in Turkey and evaluate their nutritional quality. The hydrolysis index of breakfast cereals ranged from 78.1 to 114.9, whereas the GI ranged from 82.6 to 102.8. The GI of 6 out of 12 breakfast cereal products was higher than that of white bread. Free sugar content, rapidly available glucose, and resistant starch amounts were significantly related to the increase and decrease of GIs in breakfast cereals, but there was no significant relationship between rapidly and slowly digestible starches. This may be related to the free sugar content in the samples and the extent of extrusion used for the samples. When the breakfast cereal groups were evaluated, overall, the GIs of samples containing oats were lower than those containing rice and corn.

Optimized preparation of anthocyanin-rich extract from black rice and its effects on in vitro digestibility

The procedure for obtaining anthocyanin-enriched extracts from black rice was optimized by response surface methodology, and the effects of the optimized extract on in vitro starch digestibility were investigated in a wheat flour gel model. The experimental results were well-described by a polynomial multiple regression model (R² = 0.8812, p = 0.0546) with regard to anthocyanin content in anthocyanin-enriched extracts from black rice. The optimal conditions for obtaining anthocyanin-enriched extracts from black rice were 50.78% ethanol and 1 N HCl (0.60 mL), yielding a predicted anthocyanin content of 624.27 mg cyanidin 3 glucoside extract. The optimized anthocyanin-enriched extract was a stronger inhibitor of α-glucosidase than acarbose. Furthermore, the predicted glycemic index values of gels prepared with the optimized extract were significantly lower than that of wheat flour gel. These results indicate that the optimized extract suppressed starch hydrolysis by inhibiting digestive enzymes.

Non-cereal ingredients for the attenuation of glycaemic response to bread: a review of the clinical evidence

Enrichment of bread with non-cereal ingredients could favourably influence postprandial glucose response to bread.

Gut microorganisms as promising targets for the management of type 2 diabetes

Each human intestine harbours not only hundreds of trillions of bacteria but also bacteriophage particles, viruses, fungi and archaea, which constitute a complex and dynamic ecosystem referred to as the gut microbiota. An increasing number of data obtained during the last 10 years have indicated changes in gut bacterial composition or function in type 2 diabetic patients. Analysis of this 'dysbiosis' enables the detection of alterations in specific bacteria, clusters of bacteria or bacterial functions associated with the occurrence or evolution of type 2 diabetes; these bacteria are predominantly involved in the control of inflammation and energy homeostasis. Our review focuses on two key questions: does gut dysbiosis truly play a role in the occurrence of type 2 diabetes, and will recent discoveries linking the gut microbiota to host health be helpful for the development of novel therapeutic approaches for type 2 diabetes? Here we review how pharmacological, surgical and nutritional interventions for type 2 diabetic patients may impact the gut microbiota. Experimental studies in animals are identifying which bacterial metabolites and components act on host immune homeostasis and glucose metabolism, primarily by targeting intestinal cells involved in endocrine and gut barrier functions. We discuss novel approaches (e.g. probiotics, prebiotics and faecal transfer) and the need for research and adequate intervention studies to evaluate the feasibility and relevance of these new therapies for the management of type 2 diabetes.

Effect of Black Tea and Black Tea Pomace Polyphenols on α-Glucosidase and α-Amylase Inhibition, Relevant to Type 2 Diabetes Prevention

This study evaluates the potential mechanism of action and bioactivity of black tea and black tea pomace for type 2 diabetes prevention via inhibition of carbohydrate hydrolyzing enzymes. Black tea leaves were extracted in hot water and black tea pomace was extracted in 70% acetone. The phenolic content of the water extract (WBT) and pomace acetone extracts (AOBT) were 5.77 and 8.9 mg/mL, respectively, both based on the same concentration of solid tea in the extract. The water extract was subjected to C18 extraction and the resulting hydrophobic fraction (HBBT) was further subjected to LH-20 extraction to recover a low molecular weight phenolic enriched fraction (LMW) and a high molecular weight enriched fraction (HMW). The phenolic content of the LMW and HMW fraction were 1.42 and 2.66 mg/mL, respectively. Among water extracts the HMW fraction was most bioactive against α-glucosidase (IC50 = 8.97 μg/mL) followed by HBBT fraction (IC50 = 14.83 μg/mL). However, the HBBT fraction was the most bioactive fraction against α-amylase (IC50 = 0.049 mg/mL). The black tea pomace (AOBT) had significant α-glucosidase inhibitory activity (IC50 = 14.72 μg/mL) but lower α-amylase inhibitory activity (IC50 = 0.21 mg/mL). The phenolic profiles for LMW and HMW fractions were evaluated using HPLC and the differences between the two profiles were identified. Further research is underway to identify and evaluate the phenolic compounds that are present in the HMW fraction. Our findings suggest that black tea and black tea pomace has potential for carbohydrate hydrolyzing enzyme inhibition and this activity depends on high molecular weight phenolic compounds.

Can bread processing conditions alter glycaemic response?

Bread is a staple food that is traditionally made from wheat flour. This study aimed to compare the starch digestibility of western baked bread and oriental steamed bread. Four types of bread were prepared: western baked bread (WBB) and oriental steamed bread (OSB), modified baked bread (MBB) made with the OSB recipe and WBB processing, and modified steamed bread (MSB) made with the WBB recipe and OSB processing. MBB showed the highest starch digestibility in vitro, followed by WBB, OSB and MSB. A similar trend was observed for glycaemic response in vivo. MBB, WBB, OSB and MSB had a glycaemic index of 75±4, 71±5, 68±5 and 65±4, respectively. Processing differences had a more pronounced effect on starch digestibility in bread, and steamed bread was healthier in terms of glycaemic response. The manipulation of processing conditions could be an innovative route to alter the glycaemic response of carbohydrate-rich foods.