The effect of short-chain fatty acids on glycemic control in humans: A systematic review and meta-analysis

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

Effect of semolina pudding prepared from starch branching enzyme IIa and b mutant wheat on glycaemic response in vitro and in vivo: a randomised controlled pilot study

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

The association of mycoprotein-based foods consumption with diet quality, energy intake and non-communicable diseases' risk in the UK adult population using the National Diet and Nutrition Survey (NDNS) years 2008/09-2016/17: A cross-sectional study.

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<0.001), DASH score (+23.33%) and HDI (+8.89%) (p<0.001, both) and lower BMI (-4.77%,p=0.00) vs. non-consumers. There was an association (p=0.00) between mycoprotein consumers and diet quality scores (+0.19 and +0.26), high fibre (+3.17g), 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 haemoglobin A1c (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

Effects of mycoprotein on glycaemic control and energy intake in humans: a systematic review

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 21 studies were identified of which only 5 studies, totalling 122 participants, met the inclusion criteria. All 5 studies were acute studies of which 1 reported outcomes on glycaemia and insulinaemia, 2 reported on energy intake and 2 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-24h 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