Plant-Based Dairy Alternatives Contribute to a Healthy and Sustainable Diet.

Plant-based foods are increasing in popularity as more and more people are concerned about personal and planetary health. The consumption of plant-based dairy alternatives (PBDAs) has assumed a more significant dietary role in populations shifting to more sustainable eating habits. Plant-based drinks (PBDs) made from soya and other legumes have ample protein levels. PBDs that are appropriately fortified have adequate levels of important vitamins and minerals comparable to dairy milk. For the PBDs examined, the greenhouse gas emissions were diminished by 59-71% per 250 mL, and the land use and eutrophication impact was markedly less than the levels displayed by dairy milk. The water usage for the oat and soya drinks, but not rice drinks, was substantially lower compared to dairy milk. When one substitutes the 250 mL serving of dairy milk allowed within the EAT Lancet Planetary Health Diet for a fortified plant-based drink, we found that the nutritional status is not compromised but the environmental footprint is reduced. Combining a nutrient density score with an environmental index can easily lead to a misclassification of food when the full nutrition profile is not utilized or only a selection of environmental factors is used. Many PBDAs have been categorized as ultra-processed foods (UPFs). Such a classification, with the implied adverse nutritional and health associations, is inconsistent with current findings regarding the nutritional quality of such products and may discourage people from transitioning to a plant-based diet with its health and environmental advantages.

A Comprehensive Analysis of the Nutritional Composition of Plant-Based Drinks and Yogurt Alternatives in Europe.

Concerns for human and planetary health have led to a shift towards healthier plant-based diets. Plant-based dairy alternatives (PBDA) have experienced exponential market growth due to their lower environmental impact compared to dairy products. However, questions have arisen regarding their suitability as dairy substitutes and their role in food-based dietary guidelines (FBDG). Our study aimed to analyse the nutritional profiles of leading PBDA across Europe and compare them with their dairy counterparts. We examined the nutritional profiles of 309 unflavoured PBDA representing the European market leaders, including 249 plant-based drinks (PBD) and 52 plant-based alternatives to yogurt (PBAY). PBD and PBAY, excluding coconut varieties, were low in saturated fat (<1 g per serving). Seventy percent of PBDA were unsweetened, and most had sugar levels comparable to dairy. Except for soya varieties, PBDA protein levels were lower than dairy. Organic PBDA lacked micronutrients due to legal restrictions on fortification. Among non-organic PBDA, 76% were fortified with calcium, 66% with vitamin D, and 60% with vitamin B12. Less than half were fortified with vitamin B2, and a few with iodine (11%) and vitamin A (6%). PBAY were less frequently fortified compared to PBD. PBDA displayed a favourable macronutrient profile despite lower protein levels, which would be compensated for by other protein-dense foods in a usual mixed diet. Enhancing fortification consistency with dairy-associated micronutrients would address concerns regarding PBDA's integration into FBDG. Our analysis supports the inclusion of fortified PBDA in environmentally sustainable FBDG for healthy populations.

Impact of Phenol-Enriched Olive Oils on Serum Metabonome and Its Relationship with Cardiometabolic Parameters: A Randomized, Double-Blind, Cross-Over, Controlled Trial.

Phenol-rich foods consumption such as virgin olive oil (VOO) has been shown to have beneficial effects on cardiovascular diseases. The broader biochemical impact of VOO and phenol-enriched OOs remains, however, unclear. A randomized, double-blind, cross-over, controlled trial was performed with thirty-three hypercholesterolemic individuals who ingested for 3-weeks (25 mL/day): (1) an OO enriched with its own olive oil phenolic compounds (PCs) (500 ppm; FOO); (2) an OO enriched with its own olive oil PCs (250 ppm) plus thyme PCs (250 ppm; FOOT); and (3) a VOO with low phenolic content (80 ppm). Serum lipid and glycemic profiles, serum 1H-NMR spectroscopy-based metabolomics, endothelial function, blood pressure, and cardiovascular risk were measured. We combined OPLS-DA with machine learning modelling to identify metabolites discrimination of the treatment groups. Both phenol-enriched OO interventions decreased the levels of glutamine, creatinine, creatine, dimethylamine, and histidine in comparison to VOO one. In addition, FOOT decreased the plasma levels of glycine and DMSO2 compared to VOO, while FOO decreased the circulating alanine concentrations but increased the plasma levels of acetone and 3-HB compared to VOO. Based on these findings, phenol-enriched OOs were shown to result in a favorable shift in the circulating metabolic phenotype, inducing a reduction in metabolites associated with cardiometabolic diseases.

Neither soyfoods nor isoflavones warrant classification as endocrine disruptors: a technical review of the observational and clinical data.

Soybeans are a rich source of isoflavones, which are classified as phytoestrogens. Despite numerous proposed benefits, isoflavones are often classified as endocrine disruptors, based primarily on animal studies. However, there are ample human data regarding the health effects of isoflavones. We conducted a technical review, systematically searching Medline, EMBASE, and the Cochrane Library (from inception through January 2021). We included clinical studies, observational studies, and systematic reviews and meta-analyses (SRMA) that examined the relationship between soy and/or isoflavone intake and endocrine-related endpoints. 417 reports (229 observational studies, 157 clinical studies and 32 SRMAs) met our eligibility criteria. The available evidence indicates that isoflavone intake does not adversely affect thyroid function. Adverse effects are also not seen on breast or endometrial tissue or estrogen levels in women, or testosterone or estrogen levels, or sperm or semen parameters in men. Although menstrual cycle length may be slightly increased, ovulation is not prevented. Limited insight could be gained about possible impacts of in utero isoflavone exposure, but the existing data are reassuring. Adverse effects of isoflavone intake were not identified in children, but limited research has been conducted. After extensive review, the evidence does not support classifying isoflavones as endocrine disruptors.

Low-Molecular-Weight Seaweed-Derived Polysaccharides Lead to Increased Faecal Bulk but Do Not Alter Human Gut Health Markers.

Seaweeds are potentially sustainable crops and are receiving significant interest because of their rich bioactive compound content; including fatty acids, polyphenols, carotenoids, and complex polysaccharides. However, there is little information on the in vivo effects on gut health of the polysaccharides and their low-molecular-weight derivatives. Herein, we describe the first investigation into the prebiotic potential of low-molecular-weight polysaccharides (LMWPs) derived from alginate and agar in order to validate their in vivo efficacy. We conducted a randomized; placebo-controlled trial testing the impact of alginate and agar LWMPs on faecal weight and other markers of gut health and on composition of gut microbiota. We show that these LMWPs led to significantly increased faecal bulk (20-30%). Analysis of gut microbiome composition by sequencing indicated no significant changes attributable to treatment at the phylum and family level, although FISH analysis showed an increase in Faecalibacterium prausnitzii in subjects consuming agar LMWP. Sequence analysis of gut bacteria corroborated with the FISH data, indicating that alginate and agar LWMPs do not alter human gut microbiome health markers. Crucially, our findings suggest an urgent need for robust and rigorous human in vivo testing-in particular, using refined seaweed extracts.

Development of a prebiotic blend to influence in vitro fermentation effects, with a focus on propionate, in the gut.

Short chain fatty acids (SCFAs) derived from the human gut microbiota, and in particular propionate, may beneficially influence metabolic processes such as appetite regulation. Development of prebiotics that induce high propionate levels during fermentation is desirable. A total of 11 candidate prebiotics were screened to investigate their fermentation characteristics, with a focus on propionate production in mixed anaerobic batch culture of faecal bacteria. Further to this, a continuous 3-stage colonic fermentation model (simulating the human colon) was used to evaluate changes in microbial ecology, lactate and SCFA production of three 50:50 blends, comprising both slow and rapidly fermented prebiotics. In mixed batch culture: xylo-oligosaccharide, polydextrose and α-gluco-oligosaccharide were associated with the greatest increase in propionate. Polydextrose, α-gluco-oligosaccharide, ß-1,4 glucan and oat fibre induced the greatest reductions in the acetate to propionate ratio. The most bifidogenic prebiotics were the oligosaccharides. Fermentation of a 50:50 blend of inulin and arabinoxylan, through the continuous 3-stage colonic fermentation model, induced a substantial and sustained release of propionate. The sustained release of propionate through the colon, if replicable in vivo, could potentially influence blood glucose, blood lipids and appetite regulation, however, dietary intervention studies are needed. Bifidogenic effects were also observed for the inulin and arabinoxylan blend and an increase synthesis of butyrate and lactate, thus indicating wider prebiotic potential.

Impact of dietary supplementation with resistant dextrin (NUTRIOSE®) on satiety, glycaemia, and related endpoints, in healthy adults.

PURPOSE: Resistant dextrin (RD) supplementation has been shown to alter satiety, glycaemia, and body weight, in overweight Chinese men; however, there are limited data on its effects in other demographic groups. Here, we investigated the effects of RD on satiety in healthy adults living in the United Kingdom. METHODS: 20 normal weight and 16 overweight adults completed this randomised controlled cross-over study. Either RD (14 g/day NUTRIOSE® FB06) or maltodextrin control was consumed in mid-morning and mid-afternoon preload beverages over a 28-day treatment period with crossover after a 28-day washout. During 10-h study visits (on days 1, 14, and 28 of each treatment period), satietogenic, glycaemic and anorectic hormonal responses to provided meals were assessed. RESULTS: Chronic supplementation with RD was associated with higher fasted satiety scores at day 14 (P = 0.006) and day 28 (P = 0.040), compared to control. RD also increased satiety after the mid-morning intervention drink, but it was associated with a reduction in post-meal satiety following both the lunch and evening meals (P < 0.01). The glycaemic response to the mid-morning intervention drink (0-30 min) was attenuated following RD supplementation (P < 0.01). Whilst not a primary endpoint we also observed lower systolic blood pressure at day 14 (P = 0.035) and 28 (P = 0.030), compared to day 1, following RD supplementation in the normal weight group. Energy intake and anthropometrics were unaffected. CONCLUSIONS: RD supplementation modified satiety and glycaemic responses in this cohort, further studies are required to determine longer-term effects on body weight control and metabolic markers. CLINICALTRIALS. GOV REGISTRATION: NCT02041975 (22/01/2014).

High-resolution magnetic resonance and mass spectrometry imaging of the human larynx.

High-resolution, noninvasive and nondestructive imaging of the subepithelial structures of the larynx would enhance microanatomic tissue assessment and clinical decision making; similarly, in situ molecular profiling of laryngeal tissue would enhance biomarker discovery and pathology readout. Towards these goals, we assessed the capabilities of high-resolution magnetic resonance imaging (MRI) and matrix-assisted laser desorption/ionisation-mass spectrometry (MALDI-MS) imaging of rarely reported paediatric and adult cadaveric larynges that contained pathologies. The donors were a 13-month-old male, a 10-year-old female with an infraglottic mucus retention cyst and a 74-year-old female with advanced polypoid degeneration and a mucus retention cyst. MR and molecular imaging data were corroborated using whole-organ histology. Our MR protocols imaged the larynges at 45-117 µm2 in-plane resolution and capably resolved microanatomic structures that have not been previously reported radiographically-such as the vocal fold superficial lamina propria, vocal ligament and macula flavae; age-related tissue features-such as intramuscular fat deposition and cartilage ossification; and the lesions. Diffusion tensor imaging characterised differences in water diffusivity, primary tissue fibre orientation, and fractional anisotropy between the intrinsic laryngeal muscles, mucosae and lesions. MALDI-MS imaging revealed peptide signatures and putative protein assignments for the polypoid degeneration lesion and the N-glycan constituents of one mucus retention cyst. These imaging approaches have immediate application in experimental research and, with ongoing technology development, potential for future clinical application.

Ex vivo fecal fermentation of human ileal fluid collected after raspberry consumption modifies (poly)phenolics and modulates genoprotective effects in colonic epithelial cells.

Diets rich in fruit and vegetables are associated with a decreased incidence of colorectal cancer (CRC) due, in part, to the bioactive (poly)phenolic components and their microbiota-mediated metabolites. This study investigated how such compounds, derived from ingested raspberries in the gastrointestinal tract, may exert protective effects by reducing DNA damage. Ileal fluids collected pre- and post-consumption of 300 g of raspberries by ileostomists (n = 11) were subjected to 24 h ex vivo fermentation with fecal inoculum to simulate interaction with colonic microbiota. The impact of fermentation on (poly)phenolics in ileal fluid was determined and the bioactivity of ileal fluids pre- and post fermentation investigated. (Poly)phenolic compounds including sanguiin H-6, sanguiin H-10 and cyanidin-3-O-sophoroside decreased significantly during fermentation while, in contrast, microbial catabolites, including 3-(3'-hydroxyphenyl)propanoic acid, 3-hydroxybenzoic acid and benzoic acid increased significantly. The post-raspberry ileal fermentate from 9 of the 11 ileostomates significantly decreased DNA damage (~30%) in the CCD 841 CoN normal cell line using an oxidative challenge COMET assay. The raspberry ileal fermentates also modulated gene expression of the nuclear factor 2-antioxidant responsive element (Nrf2-ARE) pathway involved in oxidative stress cytoprotection, namely Nrf2, NAD(P)H dehydrogenase, quinone-1 and heme oxygenase-1. Four of the phenolic catabolites were assessed individually, each significantly reducing DNA damage from an oxidative challenge over a physiologically relevant 10-100 µM range. They also induced a differential pattern of expression of key genes in the Nrf2-ARE pathway in CCD 841 CoN cells. The study indicates that the colon-available raspberry (poly)phenols and their microbial-derived catabolites may play a role in protection against CRC in vivo.

Sulforaphane-enriched extracts from glucoraphanin-rich broccoli exert antimicrobial activity against gut pathogens in vitro and innovative cooking methods increase in vivo intestinal delivery of sulforaphane.

PURPOSE: Studies on broccoli (Brassica oleracea var. italica) indicate beneficial effects against a range of chronic diseases, commonly attributed to their bioactive phytochemicals. Sulforaphane, the bioactive form of glucoraphanin, is formed by the action of the indigenous enzyme myrosinase. This study explored the role that digestion and cooking practices play in bioactivity and bioavailability, especially the rarely considered dose delivered to the colon. METHODS: The antimicrobial activity of sulforaphane extracts from raw, cooked broccoli and cooked broccoli plus mustard seeds (as a source myrosinase) was assessed. The persistence of broccoli phytochemicals in the upper gastrointestinal tract was analysed in the ileal fluid of 11 ileostomates fed, in a cross-over design, broccoli soup prepared with and without mustard seeds. RESULTS: The raw broccoli had no antimicrobial activity, except against Bacillus cereus, but cooked broccoli (with and without mustard seeds) showed considerable antimicrobial activity against various tested pathogens. The recovery of sulforaphane in ileal fluids post soup consumption was < 1% but the addition of mustard seeds increased colon-available sulforaphane sixfold. However, when sulforaphane was extracted from the ileal fluid with the highest sulforaphane content and tested against Escherichia coli K12, no inhibitory effects were observed. Analysis of glucosinolates composition in ileal fluids revealed noticeable inter-individual differences, with six "responding" participants showing increases in glucosinolates after broccoli soup consumption. CONCLUSIONS: Sulforaphane-rich broccoli extracts caused potent antimicrobial effects in vitro, and the consumption of sulforaphane-enriched broccoli soup may inhibit bacterial growth in the stomach and upper small intestine, but not in the terminal ileum or the colon.

Aryl hydrocarbon Receptor activation during in vitro and in vivo digestion of raw and cooked broccoli (brassica oleracea var. Italica).

Broccoli is rich in glucosinolates, which can be converted upon chewing and processing into Aryl hydrocarbon Receptor (AhR) ligands. Activation of AhR plays an important role in overall gut homeostasis but the role of broccoli processing on the generation of AhR ligands is still largely unknown. In this study, the effects of temperature, cooking method (steaming versus boiling), gastric pH and further digestion of broccoli on AhR activation were investigated in vitro and in ileostomy subjects. For the in vitro study, raw, steamed (t = 3 min and t = 6 min) and boiled (t = 3 min and t = 6 min) broccoli were digested in vitro with different gastric pH. In the in vivo ileostomy study, 8 subjects received a broccoli soup or a broccoli soup plus an exogenous myrosinase source. AhR activation was measured in both in vitro and in vivo samples by using HepG2-Lucia™ AhR reporter cells. Cooking broccoli reduced the AhR activation measured after gastric digestion in vitro, but no effect of gastric pH was found. Indole AhR ligands were not detected or detected at very low levels both after intestinal in vitro digestion and in the ileostomy patient samples, which resulted in no AhR activation. This suggests that the evaluation of the relevance of glucosinolates for AhR modulation in the gut cannot prescind from the way broccoli is processed, and that broccoli consumption does not necessarily produce substantial amounts of AhR ligands in the large intestine.

Expert consensus on low-calorie sweeteners: facts, research gaps and suggested actions.

A consensus workshop on low-calorie sweeteners (LCS) was held in November 2018 where seventeen experts (the panel) discussed three themes identified as key to the science and policy of LCS: (1) weight management and glucose control; (2) consumption, safety and perception; (3) nutrition policy. The aims were to identify the reliable facts on LCS, suggest research gaps and propose future actions. The panel agreed that the safety of LCS is demonstrated by a substantial body of evidence reviewed by regulatory experts and current levels of consumption, even for high users, are within agreed safety margins. However, better risk communication is needed. More emphasis is required on the role of LCS in helping individuals reduce their sugar and energy intake, which is a public health priority. Based on reviews of clinical evidence to date, the panel concluded that LCS can be beneficial for weight management when they are used to replace sugar in products consumed in the diet (without energy substitution). The available evidence suggests no grounds for concerns about adverse effects of LCS on sweet preference, appetite or glucose control; indeed, LCS may improve diabetic control and dietary compliance. Regarding effects on the human gut microbiota, data are limited and do not provide adequate evidence that LCS affect gut health at doses relevant to human use. The panel identified research priorities, including collation of the totality of evidence on LCS and body weight control, monitoring and modelling of LCS intakes, impacts on sugar reduction and diet quality and developing effective communication strategies to foster informed choice. There is also a need to reconcile policy discrepancies between organisations and reduce regulatory hurdles that impede low-energy product development and reformulation.

Metabolic targets of watercress and PEITC in MCF-7 and MCF-10A cells explain differential sensitisation responses to ionising radiation.

PURPOSE: Watercress is a rich source of phytochemicals with anticancer potential, including phenethyl isothiocyanate (PEITC). We examined the potential for watercress extracts and PEITC to increase the DNA damage caused by ionising radiation (IR) in breast cancer cells and to be protective against radiation-induced collateral damage in healthy breast cells. The metabolic events that mediate such responses were explored using metabolic profiling. METHODS: 1H nuclear magnetic resonance spectroscopy-based metabolic profiling was coupled with DNA damage-related assays (cell cycle, Comet assay, viability assays) to profile the comparative effects of watercress and PEITC in MCF-7 breast cancer cells and MCF-10A non-tumorigenic breast cells with and without exposure to IR. RESULTS: Both the watercress extract and PEITC-modulated biosynthetic pathways of lipid and protein synthesis and resulted in changes in cellular bioenergetics. Disruptions to the redox balance occurred with both treatments in the two cell lines, characterised by shifts in the abundance of glutathione. PEITC enhanced the sensitivity of the breast cancer cells to IR increasing the effectiveness of the cancer-killing process. In contrast, watercress-protected non-tumorigenic breast cells from radiation-induced damage. These effects were driven by changes in the cellular content of the antioxidant glutathione following exposure to PEITC and other phytochemicals in watercress. CONCLUSION: These findings support the potential prophylactic impact of watercress during radiotherapy. Extracted compounds from watercress and PEITC differentially modulate cellular metabolism collectively enhancing the therapeutic outcomes of radiotherapy.

Modelling the role of microbial p-cresol in colorectal genotoxicity.

Background: A greater understanding of mechanisms explaining the interactions between diet and the gut microbiota in colorectal cancer is desirable. Genotoxic microbial metabolites present in the colon may be implicated in carcinogenesis and potentially influenced by diet. Aims: We hypothesised that microbial p-cresol is a colonic genotoxin and set out to model potential exposures in the colon and the effects of these exposures on colonic cells. Methods: Batch culture fermentations with human faecal inoculate were used to determine the synthesis of p-cresol and other metabolites in response to various substrates. The fermentation supernatants were evaluated for genotoxicity and the independent effects of p-cresol on colonic cells were studied in vitro. Results: In batch culture fermentation, supplementary protein increased the synthesis of phenols, indoles and p-cresol, whereas supplementary fructoligosaccharide (FOS) increased the synthesis of short chain fatty acids. The p-cresol was the greatest predictor of genotoxicity against colonocytes in the fermentation supernatants. Spiking fermentation supernatants with exogenous p-cresol further increased DNA damage, and independently p-cresol induced DNA damage in a dose-dependent manner against HT29 and Caco-2 cells and influenced cell cycle kinetics. Conclusions: In the colon p-cresol may reach physiologically significant concentrations which contribute to genotoxic exposures in the intestinal lumen, p-cresol production may be attenuated by substrate, and therefore diet, making it a potential modifiable biomarker of genotoxicity in the colon.

Assessing the in vivo data on low/no-calorie sweeteners and the gut microbiota.

Low/no-calorie sweeteners (LNCS) are continually under the spotlight in terms of their safety and benefits; in 2014 a study was published linking LNCS to an enhanced risk of glucose intolerance through modulation of the gut microbiota. In response, an in-depth review of the literature was undertaken to evaluate the major contributors to potential changes in the gut microbiota and their corresponding sequelae, and to determine if consuming LNCS (e.g., acesulfame K, aspartame, cyclamate, neotame, saccharin, sucralose, steviol glycosides) contributes to changes in the microbiome based on the data reported in human and animal studies. A few rodent studies with saccharin have reported changes in the gut microbiome, but primarily at high doses that bear no relevance to human consumption. This and other studies suggesting an effect of LNCS on the gut microbiota were found to show no evidence of an actual adverse effect on human health. The sum of the data provides clear evidence that changes in the diet unrelated to LNCS consumption are likely the major determinants of change in gut microbiota numbers and phyla, confirming the viewpoint supported by all the major international food safety and health regulatory authorities that LNCS are safe at currently approved levels.

Impact of a (poly)phenol-rich extract from the brown algae Ascophyllum nodosum on DNA damage and antioxidant activity in an overweight or obese population: a randomized controlled trial.

Background: Epidemiologic evidence suggests that a diet rich in (poly)phenols has beneficial effects on many chronic diseases. Brown seaweed is a rich source of (poly)phenols. Objective: The aim of this study was to investigate the bioavailability and effect of a brown seaweed (Ascophyllum nodosum) (poly)phenol extract on DNA damage, oxidative stress, and inflammation in vivo. Design: A randomized, double-blind, placebo-controlled crossover trial was conducted in 80 participants aged 30-65 y with a body mass index (in kg/m2) ≥25. The participants consumed either a 400-mg capsule containing 100 mg seaweed (poly)phenol and 300 mg maltodextrin or a 400-mg maltodextrin placebo control capsule daily for an 8-wk period. Bioactivity was assessed with a panel of blood-based markers including lymphocyte DNA damage, plasma oxidant capacity, C-reactive protein (CRP), and inflammatory cytokines. To explore the bioavailability of seaweed phenolics, an untargeted metabolomics analysis of urine and plasma samples after seaweed consumption was determined by ultra-high-performance liquid chromatography-high-resolution mass spectrometry. Results: Consumption of the seaweed (poly)phenols resulted in a modest decrease in DNA damage but only in a subset of the total population who were obese. There were no significant changes in CRP, antioxidant status, or inflammatory cytokines. We identified phlorotannin metabolites that are considered potential biomarkers of seaweed consumption including pyrogallol/phloroglucinol-sulfate, hydroxytrifurahol A-glucuronide, dioxinodehydroeckol-glucuronide, diphlorethol sulfates, C-O-C dimer of phloroglucinol sulfate, and C-O-C dimer of phloroglucinol. Conclusions: To the best of our knowledge, this work represents the first comprehensive study investigating the bioactivity and bioavailability of seaweed (poly)phenolics in human participants. We identified several potential biomarkers of seaweed consumption. Intriguingly, the modest improvements in DNA damage were observed only in the obese subset of the total population. The subgroup analysis should be considered exploratory because it was not preplanned; therefore, it was not powered adequately. Elucidation of the biology underpinning this observation will require participant stratification according to weight in future studies. This trial was registered at clinicaltrials.gov as NCT02295878.

Stevia Leaf to Stevia Sweetener: Exploring Its Science, Benefits, and Future Potential.

Steviol glycoside sweeteners are extracted and purified from the Stevia rebaudiana Bertoni plant, a member of the Asteraceae (Compositae) family that is native to South America, where it has been used for its sweet properties for hundreds of years. With continued increasing rates of obesity, diabetes, and other related comorbidities, in conjunction with global public policies calling for reductions in sugar intake as a means to help curb these issues, low- and no-calorie sweeteners (LNCSs, also known as high-potency sweeteners) such as stevia are gaining interest among consumers and food manufacturers. This appeal is related to stevia being plant-based, zero calorie and with a sweet taste that is 50-350 times sweeter than sugar, making it an excellent choice for use in sugar- and calorie-reduced food and beverage products. Despite the fact that the safety of stevia has been affirmed by several food regulatory and safety authorities around the world, insufficient education about stevia's safety and benefits, including continuing concern with regard to the safety of LNCSs in general, deters health professionals and consumers from recommending or using stevia. Therefore, the aim of this review and the stevia symposium that preceded this review at the ASN's annual conference in 2017 was to examine, in a comprehensive manner, the state of the science for stevia, its safety and potential health benefits, and future research and application. Topics covered included metabolism, safety and acceptable intake, dietary exposure, impact on blood glucose and insulin concentrations, energy intake and weight management, blood pressure, dental caries, naturality and processing, taste and sensory properties, regulatory status, consumer insights, and market trends. Data for stevia are limited in the case of energy intake and weight management as well as for the gut microbiome; therefore, the broader literature on LNCSs was reviewed at the symposium and therefore is also included in this review.

Gut microbiota functions: metabolism of nutrients and other food components.

The diverse microbial community that inhabits the human gut has an extensive metabolic repertoire that is distinct from, but complements the activity of mammalian enzymes in the liver and gut mucosa and includes functions essential for host digestion. As such, the gut microbiota is a key factor in shaping the biochemical profile of the diet and, therefore, its impact on host health and disease. The important role that the gut microbiota appears to play in human metabolism and health has stimulated research into the identification of specific microorganisms involved in different processes, and the elucidation of metabolic pathways, particularly those associated with metabolism of dietary components and some host-generated substances. In the first part of the review, we discuss the main gut microorganisms, particularly bacteria, and microbial pathways associated with the metabolism of dietary carbohydrates (to short chain fatty acids and gases), proteins, plant polyphenols, bile acids, and vitamins. The second part of the review focuses on the methodologies, existing and novel, that can be employed to explore gut microbial pathways of metabolism. These include mathematical models, omics techniques, isolated microbes, and enzyme assays.

Systematic review of the effects of the intestinal microbiota on selected nutrients and non-nutrients.

PURPOSE: There is considerable interest in the effects of the intestinal microbiota (IM) composition, its activities in relation with the metabolism of dietary substrates and the impact these effects may have in the development and prevention of certain non-communicable diseases. It is acknowledged that a complex interdependence exists between the IM and the mammalian host and that the IM possesses a far greater diversity of genes and repertoire of metabolic and enzymatic capabilities than their hosts. However, full knowledge of the metabolic activities and interactions of the IM and the functional redundancy that may exist are lacking. Thus, the current review aims to assess recent literature relating to the role played by the IM in the absorption and metabolism of key nutrients and non-nutrients. METHODS: A systematic review (PROSPERO registration: CRD42015019087) was carried out focussing on energy and the following candidate dietary substrates: protein, carbohydrate, fat, fibre, resistant starch (RS), and polyphenols to further understand the effect of the IM on the dietary substrates and the resulting by-products and host impacts. Particular attention was paid to the characterisation of the IM which are predominantly implicated in each case, changes in metabolites, and indirect markers and any potential impacts on the host. RESULTS: Studies show that the IM plays a key role in the metabolism of the substrates studied. However, with the exception of studies focusing on fibre and polyphenols, there have been relatively few recent human studies specifically evaluating microbial metabolism. In addition, comparison of the effects of the IM across studies was difficult due to lack of specific analysis/description of the bacteria involved. Considerable animal-derived data exist, but experience suggests that care must be taken when extrapolating these results to humans. Nevertheless, it appears that the IM plays a role in energy homeostasis and that protein microbial breakdown and fermentation produced ammonia, amines, phenols and branch chain fatty acids, and a greater diversity in the microbes present. Few recent studies appear to have evaluated the effect of the IM composition and metabolism per se in relation with digestible dietary carbohydrate or fat in humans. Intakes of RS and prebiotics altered levels of specific taxa that selectively metabolised specific prebiotic/carbohydrate-type substances and levels of bifidobacteria and lactobacilli were observed to increase. In controlled human studies, consistent data exist that show a correlation between the intake of fibre and an increase in bifidobacteria and short-chain fatty acids, in particular butyrate, which leads to lower intestinal pH. Dietary polyphenols rely on modification either by host digestive enzymes or those derived from the IM for absorption to occur. In the polyphenol-related studies, a large amount of inter-individual variation was observed in the microbial metabolism and absorption of certain polyphenols. CONCLUSIONS: The systematic review demonstrates that the IM plays a major role in the breakdown and transformation of the dietary substrates examined. However, recent human data are limited with the exception of data from studies examining fibres and polyphenols. Results observed in relation with dietary substrates were not always consistent or coherent across studies and methodological limitations and differences in IM analyses made comparisons difficult. Moreover, non-digestible components likely to reach the colon are often not well defined or characterised in studies making comparisons between studies difficult if not impossible. Going forward, further rigorously controlled randomised human trials with well-defined dietary substrates and utilizing omic-based technologies to characterise and measure the IM and their functional activities will advance the field. Current evidence suggests that more detailed knowledge of the metabolic activities and interactions of the IM hold considerable promise in relation with host health.