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Noncommunicable disease development is related to impairments in glycemic and insulinemic responses, which can be modulated by fiber intake. Fiber's beneficial effects upon metabolic health can be partially attributed to the production of SCFAs via microbial fermentation of fiber in the gastrointestinal tract.We aimed to determine the effects of SCFAs, acetate, propionate, and butyrate on glycemic control in humans.The CENTRAL, Embase, PubMed, Scopus, and Web of Science databases were searched from inception to 7 December 2021. Papers were included if they reported a randomized controlled trial measuring glucose and/or insulin compared to a placebo in adults. Studies were categorized by the type of SCFA and intervention duration. Random-effects meta-analyses were performed for glucose and insulin for those subject categories with ≥3 studies, or a narrative review was performed.We identified 43 eligible papers, with 46 studies within those records (n = 913), and 44 studies were included in the meta-analysis. Vinegar intake decreased the acute glucose response [standard mean difference (SMD), -0.53; 95% CI, -0.92 to -0.14; n = 67] in individuals with impaired glucose tolerance or type 2 diabetes and in healthy volunteers (SMD, -0.27; 95% CI, -0.54 to 0.00; n = 186). The meta-analyses for acute acetate, as well as acute and chronic propionate studies, showed no significant effect.Vinegar decreased the glucose response acutely in healthy and metabolically unhealthy individuals. Acetate, propionate, butyrate, and mixed SCFAs had no effect on blood glucose and insulin in humans. Significant heterogeneity, risks of bias, and publication biases were identified in several study categories, including the acute vinegar glucose response. As evidence was very uncertain, caution is urged when interpreting these results. Further high-quality research is required to determine the effects of SCFAs on glycemic control.

High-fibre diets are beneficial for many health outcomes via a wide range of mechanisms including gut microbiota fermentation-derived short-chain fatty acid (SCFAs) production. Mycoprotein (marketed as Quorn) is a food high in fibre (>6 g/100 g wet weight (ww)) and protein (13 g/100 g ww) which has been shown to have positive effects on glycemic control and appetite in humans. Nevertheless, the mechanisms underpinning this are poorly understood. Here, we investigate the changes in gut microbiota α- and β-diversity, pH and SCFAs production in faecal batch cultures supplemented with pre-digested mycoprotein (Quorn), soy, chicken and control (unsupplemented) using eight fresh stools from healthy donors. The results showed that pre-digested mycoprotein did not alter pH (p = .896), α- or β-diversity of the gut microbiota when compared to the control, soy, and chicken. Nevertheless, chicken led to a significant increase in total SCFAs post-24 h vs. control (+57.07 mmol/L, p = .01). In particular, propionate increased when compared to soy (+19.59 mmol/L, p = .03) and the control (+23.19 mmol/L, p < .01). No other differences in SCFAs were detected. In conclusion, pre-digested mycoprotein was not fermented in vitro by healthy gut microbiota in the settings of this experiment.

Mycoprotein is a fungal-based ingredient rich in fibre and protein used in meat substitutes called Quorn. Fibre and protein positively regulate glycaemia, lipidaemia and energy intake which are non-communicable diseases’ (NCD) markers. We performed a cross-sectional study to investigate the association of mycoprotein intake with diet quality, nutrient, energy intake and NCD risk within 5507 UK free-living adults from the National Diet and Nutrition Survey from years 2008/2009 to 2016/2017. Dietary approaches to stop hypertension (DASH) and healthy diet index (HDI) were calculated to estimate diet quality. Comparison between mycoprotein consumers (>1 % kcal) and non-consumers, and associations between consumers and nutrient intakes, NCD’s risk markers and diet quality were investigated using a survey-adjusted general linear model adjusted for sex, age, BMI, ethnicity, socio-economic, smoking status, region of residency, total energy, energy density, HDI and non-mycoprotein fibre intake. Mycoprotein consumers (3·44 % of the cohort) had a higher intake of dietary fibre (+22·18 %, P < 0·001), DASH score (+23·33 %) and HDI (+8·89 %) (P < 0·001, both) and lower BMI (−4·77 %, P = 0·00) v. non-consumers. There was an association (P = 0·00) between mycoprotein consumers and diet quality scores (+0·19 and +0·26), high fibre (+3·17 g), total and food energy (+3·09 and +0·22 kcal), but low energy density intakes (−0·08 kcal/g, P = 0·04). Consumers were negatively associated with fasting blood glucose (−0·31 mmol/l, P = 0·00) and glycated HbA1c (−0·15 %, P = 0·01). In conclusion, mycoprotein intake is associated with lower glycaemic markers and energy density intake, and high fibre, energy intake and diet quality scores.

Mycoprotein is a food high in both dietary fibre and non-animal-derived protein. Global mycoprotein consumption is increasing, although its effect on human health has not yet been systematically reviewed. This study aims to systematically review the effects of mycoprotein on glycaemic control and energy intake in humans. A literature search of randomised controlled trials was performed in PubMed, Embase, Web of Science, Google Scholar and hand search. A total of twenty-one studies were identified of which only five studies, totalling 122 participants, met the inclusion criteria. All five studies were acute studies of which one reported outcomes on glycaemia and insulinaemia, two reported on energy intake and two reported on all of these outcomes. Data were extracted, and risk-of-bias assessment was then conducted. The results did not show a clear effect of acute mycoprotein on blood glucose levels, but it showed a decrease in insulin levels. Acute mycoprotein intake also showed to decrease energy intake at an ad libitum meal and post-24 h in healthy lean, overweight and obese humans. In conclusion, the acute ingestion of mycoprotein reduces energy intake and insulinaemia, whereas its impact on glycaemia is currently unclear. However, evidence comes from a very limited number of heterogeneous studies. Further well-controlled studies are needed to elucidate the short- and long-term effects of mycoprotein intake on glycaemic control and energy intake, as well as the mechanisms underpinning these effects.

Background: Non-communicable disease development is related to impairments in glycaemic and insulinemic response, which can be modulated by fiber intake. Fiber's beneficial effect upon metabolic health can be partially attributed to the production of short-chain fatty acids (SCFAs) via microbial fermentation of fiber in the gastrointestinal tract. Objective: We aimed to determine the effect of the SCFAs, acetate, propionate, and butyrate on glycemic control in humans. Methods: CENTRAL, Embase, PubMed, Scopus and Web of Science databases were searched from inception to the 07/12/2021. Papers were included if they reported a randomized, controlled trial measuring glucose and/or insulin compared to a placebo in adults. Studies were categorized by the type of SCFA and intervention duration. Random effects meta-analyses were performed for glucose and insulin for those subject categories with ≥3 studies, or a narrative review was performed. Results: We identified 43 eligible papers, with 46 studies within those records (n = 913), 44 studies were included in the meta-analysis. Vinegar intake decreased acute glucose response, standard mean difference (SMD) and (95% CI) –0.53 (–0.92, –0.14) (n = 67) in individuals with impaired glucose tolerance or type 2 diabetes and in healthy (SMD) –0.27 (–0.54, 0.00) (n = 186). The meta-analyses for acute acetate as well as acute and chronic propionate studies had no significant effect. Conclusions: Vinegar decreased glucose response acutely in healthy and non-healthy. Acetate, propionate, butyrate, and mixed SCFAs had no effect on blood glucose and insulin in humans. Significant heterogeneity, risk of bias, and publication bias were identified in several study categories, including acute vinegar glucose response. As evidence was very uncertain, caution is urged when interpreting these results. Further high-quality research is required to determine the effect of SCFAs on glycemic control.

Type 2 diabetes (T2D) is a disease with a high prevalence in south Asian countries. Diet is the cornerstone strategy for the management of T2D. South Asians may have increased postprandial blood glucose responses following the same dietary challenge compared to white Europeans. Dietary fibre and protein play a role in regulating blood glucose and appetite via a myriad of mechanisms such as gut microbiota fermentation to short-chain fatty acids. Mycoprotein is a food ingredient high in both fibre and protein which has a positive effect on blood glucose and appetite in humans. Likewise, guar gum is a fibre-rich ingredient that decreases blood glucose and appetite in people with T2D. The aim of this thesis is to determine the effect of mycoprotein on glycaemia and energy intake in humans and the mechanisms underpinning these. In Study 1, the associations between mycoprotein-based food consumers and non-consumers with non-communicable disease markers such as blood glucose, energy intake and diet quality are studied in the UK free-living population using the National Diet and Nutrition Survey. The results showed that there is a positive association between mycoprotein consumers and healthy diet scores, fibre, fasting glucose and glycated haemoglobin. In Study 2, a systematic review of the effects of mycoprotein on glycaemic control and appetite in humans is performed. The results showed that the acute effects of mycoprotein on glycaemia are unclear, there is a consistent decrease in insulinaemia and energy intake in healthy humans. In Study 3, the acute effect of mycoprotein and guar gum in glycaemic control and appetite in people with T2D of South Asian and European ethnicity is investigated via a randomised controlled trial. The results showed that mycoprotein decreases postprandial blood glucose and that enriching chapati with guar gum induces a decreased blood glucose response. South Asians, however, had an increased postprandial glucose response compared to white Europeans. In Study 4, the effects of mycoprotein fermentation by the healthy gut microbiota is investigated using in vitro batch fermentation cultures. The results on breath hydrogen, pH, SCFAs, and bacterial communities, showed that mycoprotein may not be fermented. Open Access

Refined starchy foods are usually rapidly digested, leading to poor glycaemic control, but not all starchy foods are the same. Complex carbohydrates like resistant starch (RS) have been shown to reduce the metabolic risk factors for chronic diseases such as hyperglycaemia and overweight. The aim of the project was to develop a semolina-based food made from a starch branching enzyme II (sbeIIa/b-AB) durum wheat mutant with a high RS content and to measure its glycaemic index using a double-blind randomised pilot study. We report here the amylose, RS and non-starch polysaccharide concentration of raw sbeIIa/b-AB and wild-type control (WT) semolina. We measured RS after cooking to identify a model food for in vivo testing. Retrograded sbeIIa/b-AB semolina showed a higher RS concentration than the WT control (RS = 4.87 ± 0.6 g per 100 g, 0.77 ± 0.34 g per 100 g starch DWB, respectively), so pudding was selected as the test food. Ten healthy participants consumed ∼50 g of total starch from WT and sbeIIa/b-AB pudding and a standard glucose drink. Capillary blood glucose concentrations were measured in the fasting and postprandial state (2 h): incremental area-under-the-curve (iAUC) and GI were calculated. We found no evidence of difference in GI between sbeIIa/b-AB pudding and the WT control, but the starch digestibility was significantly lower in sbeIIa/b-AB pudding compared to the WT control in vitro (C90 = 33.29% and 47.38%, respectively). Based on these results, novel sbeIIa/b-AB wheat foods will be used in future in vivo studies to test the effect of different RS concentrations and different food matrices on glycaemia.

Mycoprotein is a fungal-based ingredient rich in fibre and protein used in meat-replacement foods sold under the name of Quorn in 17 countries. Fibre and protein positively regulate glycaemia, lipidaemia, energy intake which are non-communicable diseases' (NCDs) markers. We performed a cross-sectional study to investigate the association of mycoprotein intake with diet quality, nutrient, energy intake and NCDs risk within UK free-living adults from the National Diet and Nutrition Survey (NDNS) from years 2008/09-2016/17. Dietary approaches to stop hypertension (DASH) and healthy diet index (HDI) were calculated to estimate diet quality. Comparison between mycoprotein consumers (>1% kcal) and non-consumers, and associations between consumers and nutrient intakes, NCDs' risk markers and diet quality were investigated using a survey-adjusted general linear model adjusted for sex, age, body mass index (BMI), ethnicity, socio-economic, smoking status, region of residency, total energy, energy density, HDI and non-mycoprotein fibre intake. 5507 adults were included, of which 3.44% were mycoprotein consumers and had a higher intake of dietary fibre (+22.18%,p