The influence of stevia glycosides on the growth of Lactobacillus reuteri strains

Pro-pre and Postbiotic Fermentation of the Dietetic Dairy Matrix with Prebiotic Sugar Replacers

In this study, bacterial growth, postbiotic short-chain fatty acids (SCFAs) formation, and gelation properties of sugar-free probiotic milk gels produced with stevia and inulin as a sugar replacer and synbiotic interactions were investigated with regard to prebiotic/bio-therapeutic potential and consumer preference. Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis cultures were used in the manufacture of dietetic milk gels. The addition of stevia and inulin promoted the viability of bacteria and enhanced milk gel firmness throughout its shelf life. The activity of the probiotic bacteria was identified to be within the potential prebiotic effects (> 8.30 log10 cfu mL-1) in a food matrix. However, it was determined that especially stevia and stevia + inulin addition increased the survival rate of probiotic bacteria and in vitro total SCFA production with higher scores for consumers' preferences rather than with the addition of stevia alone. Yoghurts containing B. animalis subsp. lactis have improved the instrumental textural properties, whereas yoghurts containing L. acidophilus had higher scores for sensorial attributes.

Comparison of a Daily Steviol Glycoside Beverage compared with a Sucrose Beverage for Four Weeks on Gut Microbiome in Healthy Adults

BACKGROUND

Recent studies suggest that some nonnutritive sweeteners (NNS) have deleterious effects on the human gut microbiome (HGM). The effect of steviol glycosides on the HGM has not been well studied.

OBJECTIVE

We aimed to evaluate the effects of stevia- compared with sucrose-sweetened beverages on the HGM and fecal short-chain fatty acid (SCFA) profiles.

METHODS

Using a randomized, double-blinded, parallel-design study, n = 59 healthy adults [female/male, n = 36/23, aged 31±9 y, body mass index (BMI): 22.6±1.7 kg/m2] consumed 16 oz of a beverage containing either 25% of the acceptable daily intake (ADI) of stevia or 30 g of sucrose daily for 4 weeks followed by a 4-week washout. At weeks 0 (baseline), 4, and 8, the HGM was characterized via shotgun sequencing, fecal SCFA concentrations were measured using ultra-high performance liquid chromatography-tandem mass spectrometry and anthropometric measurements, fasting serum glucose, insulin and lipids, blood pressure, pulse, and 3-d diet records were obtained.

RESULTS

There were no significant differences in the HGM or fecal SCFA between the stevia and sucrose groups at baseline (P > 0.05). At week 4 (after intervention), there were no significant differences in the HGM at the phylum, family, genus, or species level between the stevia and sucrose groups and no significant differences in fecal SCFA. At week 4, BMI had increased by 0.3 kg/m2 (P = 0.013) in sucrose compared with stevia, but all other anthropometric and cardiometabolic measures and food intake did not differ significantly (P > 0.05). At week 8 (after washout), there were no significant differences in the HGM, fecal SFCA, or any anthropometric or cardiometabolic measure between the stevia and sucrose groups (P > 0.05).

CONCLUSIONS

Daily consumption of a beverage sweetened with 25% of the ADI of stevia for 4 weeks had no significant effects on the HGM, fecal SCFA, or fasting cardiometabolic measures, compared with daily consumption of a beverage sweetened with 30 g of sucrose.

TRIAL REGISTRATION

clinicaltrials.gov as NCT05264636.

Non-nutritive sweeteners and their impacts on the gut microbiome and host physiology

Non-nutritive sweeteners (NNS) are broadly incorporated into foods, especially those representing a growing share of the beverage market. NNS are viewed as a noncaloric and desirable alternative to sugar-based sweeteners and are thought to contribute to reducing overall caloric intake. While these compounds have been studied extensively and have long been considered inert, new research has presented a different view and raises new questions about the effects of NNS on human physiology. Namely, the influence on glucose responses, the gastrointestinal epithelium, and the gut microbiome. As the gut microbiome is now recognized as a major mediator of human health and perturbations to this community are generally associated with negative health trajectories or overt disease, interactions between NNS and the gut microbiome are of increasing interest to clinicians and researchers. Several NNS compounds are now hypothesized to affect human physiology by modulating the gut microbiome, though the mechanism for this action remains unclear. The purpose of this review is to discuss the history and current knowledge of NNS, their reported utility and effects on host physiology and the gut microbiome, and describes a model for investigating the underlying mechanism behind reported effects of NNS on the gut microbiome.

Effect of stevia leaves ( Stevia rebaudiana Bertoni) on diabetes: A systematic review and meta‐analysis of preclinical studies

Stevia (Stevia rebaudiana Bertoni) is a natural herb with biological activities such as anticancer, antidiabetic, anticardiovascular disease, anti‐inflammatory, and antimicrobial. The current systematic review and meta‐analysis of previously published data were performed to assess the antidiabetic effect of stevia leaves. Three electronic databases (PubMed, CENTRAL, and DOAJ) had been used for searching articles published before September 2020. Meta‐analysis via random‐effect model had been performed to assess the effects of different doses of stevia on blood glucose level (BGL) and studies were weighted according to an estimate of the standard mean difference (SMD). Overall, 16 eligible studies were selected for qualitative analysis and 9 were included for quantitative analysis. The results of the meta‐analysis for BGL showed that at the doses of 200, 300, and 400 mg/kg of stevia leaves there was a significant difference in means of BGL between the intervention and control group and the dose of 500 mg/kg showed no significance (Standard mean difference (SMD): −3.84 (−9.96, 2.27); p = .22). Based on the duration of intervention, subgroup analysis of articles showed a significant difference between the groups (p < .001). The results of the meta‐analysis support the hypothesis that stevia leaf has an antihyperglycemic effect and reduces the blood glucose level at doses of 200, 300, and 400 mg/kg. Therefore, more clinical trials on animals and humans have to be done to investigate the antidiabetic and antihyperglycemic effects along with the efficacy and safety of these medicinal leaves.

The Effects of Stevia Consumption on Gut Bacteria: Friend or Foe?

Stevia, a zero-calorie sugar substitute, is recognized as safe by the Food and Drug Administration (FDA) and the European Food Safety Authority (EFSA). In vitro and in vivo studies showed that stevia has antiglycemic action and antioxidant effects in adipose tissue and the vascular wall, reduces blood pressure levels and hepatic steatosis, stabilizes the atherosclerotic plaque, and ameliorates liver and kidney damage. The metabolism of steviol glycosides is dependent upon gut microbiota, which breaks down glycosides into steviol that can be absorbed by the host. In this review, we elucidated the effects of stevia’s consumption on the host’s gut microbiota. Due to the lack of randomized clinical trials in humans, we included in vitro using certain microbial strains and in vivo in laboratory animal studies. Results indicated that stevia consumption has a potential benefit on the microbiome’s alpha diversity. Alterations in the colonic microenvironment may depend on the amount and frequency of stevia intake, as well as on the simultaneous consumption of other dietary components. The anti-inflammatory properties of stevioside were confirmed in vitro by decreasing TNF-α, IL-1β, IL-6 synthesis and inhibiting of NF-κB transcription factor, and in vivo by inhibiting NF-κB and MAPK in laboratory animals.

Diet and the Microbiota-Gut-Brain Axis: Sowing the Seeds of Good Mental Health

Over the past decade, the gut microbiota has emerged as a key component in regulating brain processes and behavior. Diet is one of the major factors involved in shaping the gut microbiota composition across the lifespan. However, whether and how diet can affect the brain via its effects on the microbiota is only now beginning to receive attention. Several mechanisms for gut-to-brain communication have been identified, including microbial metabolites, immune, neuronal, and metabolic pathways, some of which could be prone to dietary modulation. Animal studies investigating the potential of nutritional interventions on the microbiota-gut-brain axis have led to advancements in our understanding of the role of diet in this bidirectional communication. In this review, we summarize the current state of the literature triangulating diet, microbiota, and host behavior/brain processes and discuss potential underlying mechanisms. Additionally, determinants of the responsiveness to a dietary intervention and evidence for the microbiota as an underlying modulator of the effect of diet on brain health are outlined. In particular, we emphasize the understudied use of whole-dietary approaches in this endeavor and the need for greater evidence from clinical populations. While promising results are reported, additional data, specifically from clinical cohorts, are required to provide evidence-based recommendations for the development of microbiota-targeted, whole-dietary strategies to improve brain and mental health.

Maternal Sweeteners Intake Modulates Gut Microbiota and Exacerbates Learning and Memory Processes in Adult Male Offspring

Background: There is increasing evidence that gut microbiota in offspring is derived in part from maternal environment such as diet. Thus, sweeteners intake including caloric or non-caloric during perinatal period can induce gut dysbiosis and program the offspring to develop cognitive problems later in life. Objective: To determine the effect of maternal high-sweeteners intake during gestation and lactation on gut microbiota shifts in adult male offspring rats and the impact on cognitive dysfunction. Methods: Thirty-four male pups from dams fed standard diet (Control-C, n = 10), high-sucrose diet (HS-C, n = 11), high-honey diet (Ho-C, n = 8), and high-stevia diet (HSt-C, n = 5) were fed standard diet after weaning, and body weight and food intake were recorded once a week for 26 weeks. Learning and memory tests were performed at week 23 of life using the Barnes maze. Fecal samples from the breastfeeding and adulthood periods were collected and analyzed by sequencing the 16S rRNA V3-V4 region of gut microbiota. Results: Maternal high-sucrose and stevia diets programmed the male offspring, and changes in microbial diversity by Shannon index were observed after weaning (p < 0.01). Furthermore, maternal high-stevia diet programming lasted into adulthood. The increase of Firmicutes abundance and the decrease in phylum Bacteroidetes were significant in HS-C and HSt-C groups. This led to an increase in the Firmicutes/Bacteroidetes index, although only in HS-C group was statistically significant (p < 0.05). Of note, the downstream gram-negative Bacteroidales and the upregulation of the gram-positive Clostridiales abundance contribute to cognitive dysfunction. Conclusion: These results suggest that dams fed a high-sucrose and stevia diets during gestation and lactation favor a deficient memory performance in adult male offspring rats through shifts gut microbiota diversity and relative abundance at several taxa.

Metabolic networks of the human gut microbiota

The human gut microbiota controls factors that relate to human metabolism with a reach far greater than originally expected. Microbial communities and human (or animal) hosts entertain reciprocal exchanges between various inputs that are largely controlled by the host via its genetic make-up, nutrition and lifestyle. The composition of these microbial communities is fundamental to supply metabolic capabilities beyond those encoded in the host genome, and contributes to hormone and cellular signalling that support the dynamic adaptation to changes in food availability, environment and organismal development. Poor functional exchange between the microbial communities and their human host is associated with dysbiosis, metabolic dysfunction and disease. This review examines the biology of the dynamic relationship between the reciprocal metabolic state of the microbiota-host entity in balance with its environment (i.e. in healthy states), the enzymatic and metabolic changes associated with its imbalance in three well-studied diseases states such as obesity, diabetes and atherosclerosis, and the effects of bariatric surgery and exercise.

Anti-Quorum Sensing Activity of Stevia Extract, Stevioside, Rebaudioside A and Their Aglycon Steviol

Governments are creating regulations for consumers to reduce their sugar intake, prompting companies to increase the ratio of artificial sweeteners in their products. However, there is evidence of some deleterious effects ascribed to the aforementioned synthetic agents and therefore consumers and food manufacturers have turned their attention to natural dietary sweeteners, such as stevia, to meet their sweetening needs. Stevia is generally considered safe; however, emerging scientific evidence has implicated the agent in gut microbial imbalance. In general, regulation of microbial behavior is known to depend highly on signaling molecules via quorum sensing (QS) pathways. This is also true for the gut microbial community. We, therefore, evaluated the possible role of these stevia-based natural sweeteners on this bacterial communication pathway. The use of a commercial stevia herbal supplement resulted in an inhibitory effect on bacterial communication, with no observable bactericidal effect. Purified stevia extracts, including stevioside, rebaudioside A (Reb A), and steviol revealed a molecular interaction, and possible interruption of Gram-negative bacterial communication, via either the LasR or RhlR receptor. Our in-silico analyses suggest a competitive-type inhibitory role for steviol, while Reb A and stevioside are likely to inhibit LasR-mediated QS in a non-competitive manner. These results suggest the need for further safety studies on the agents.

Impact of Steviol Glycosides and Erythritol on the Human and Cebus apella Gut Microbiome

Leaf extracts of Stevia rebaudiana, composed of more than 10 steviol glycosides (SGs), are used as non-nutritive, table sugar (sucrose) alternatives due to their high level of sweetness and low caloric impact. They are often combined with the sugar alcohol erythritol to increase volume and reduce aftertaste. Little is known of the impact of sugar alternatives on the human gut microbiota in terms of the diversity, composition, and metabolic products. Testing of SGs and erythritol using six representatives of the gut microbiota in vitro found no impact on bacterial growth, yet treatment with erythritol resulted in an enhancement of butyric and pentanoic acid production when tested using a human gut microbial community. Furthermore, administration of SGs and erythritol to a Cebus apella model resulted in changes to the gut microbial structure and diversity. Overall, the study did not find a negative impact of SGs and erythritol on the gut microbial community.

What was First, Obesity or Inflammatory Bowel Disease? What Does the Gut Microbiota Have to Do with It?

A sedentary lifestyle and inadequate nutrition often leads to disturbances in intestinal homeostasis, which may predispose people to excess body weight and metabolic syndrome. Obesity is frequently observed in patients with inflammatory bowel diseases (IBD), similar to the general population. Obesity may exert a negative effect on the course of IBD as well as reduce the response to treatment. Moreover, it may also be an additional risk factor for vein thromboembolism during the flare. In both obesity and IBD, it is of great importance to implement proper dietary ingredients that exert desirable effect on gut microbiota. The key to reducing body mass index (BMI) and alleviating the course of IBD is preserving healthy intestinal microflora.

Maternal low-dose aspartame and stevia consumption with an obesogenic diet alters metabolism, gut microbiota and mesolimbic reward system in rat dams and their offspring

OBJECTIVE

We examined the impact of maternal low-dose aspartame and stevia consumption on adiposity, glucose tolerance, gut microbiota and mesolimbic pathway in obese dams and their offspring.

DESIGN

Following obesity induction, female Sprague-Dawley rats were allocated during pregnancy and lactation to: (1) high fat/sucrose diet (HFS) +water (obese-WTR); (2) HFS +aspartame (obese-APM; 5-7 mg/kg/day); (3) HFS +stevia (obese-STV; 2-3 mg/kg/day). Offspring were weaned onto control diet and water and followed until 18 weeks. Gut microbiota and metabolic outcomes were measured in dams and offspring. Cecal matter from offspring at weaning was used for faecal microbiota transplant (FMT) into germ-free (GF) mice.

RESULTS

Maternal APM and STV intake with a HFS diet increased body fat in offspring at weaning and body weight long-term with APM. Maternal APM/HFS consumption impaired glucose tolerance in male offspring at age 8 weeks and both APM and STV altered faecal microbiota in dams and offspring. Maternal obesity/HFS diet affected offspring adiposity and glucose tolerance more so than maternal LCS consumption at age 12 and 18 weeks. APM and STV altered expression of genes in the mesolimbic reward system that may promote consumption of a palatable diet. GF mice receiving an FMT from obese-APM and obese-STV offspring had greater weight gain and body fat and impaired glucose tolerance compared with obese-WTR.

CONCLUSION

Maternal low-calorie sweetener consumption alongside HFS may disrupt weight regulation, glucose control and gut microbiota in dams and their offspring most notably in early life despite no direct low-calorie sweetener consumption by offspring.

The hidden hazardous effects of stevia and sucralose consumption in male and female albino mice in comparison to sucrose

Replacing sucrose with non-caloric sweeteners is an approach to avoid overweight and diabetes development. Non-caloric sweeteners are classified into either artificial as sucralose or natural as stevia. Both of them have been approved by FDA, but the effects of their chronic consumption are controversial. The present study aimed to evaluate the effects of these two sweeteners, in male and female albino mice, on different blood biochemical parameters, enzymes activities and immunological parameters after 8 and 16 weeks of sweeteners administration. 40.5 mg/ml of sucrose, 5.2 mg/ml of sucralose and 4.2 mg/ml of stevia were dissolved individually in distilled water. Mice were administrated by sweetener's solution for 5 h daily. Male and female mice showed a preference for water consumption with sucralose or stevia. Both of the two sweeteners significantly reduced the hemoglobin level, HCT%, RBCs and WBCs count. After 18 weeks, significant elevations in liver and kidney function enzymes were observed in male and female mice administrated with both non-caloric sweeteners. Histopathological examination in sucralose and stevia administrated groups confirmed the biochemical results; where it revealed a severe damage in liver and kidney sections. While, sucrose administration elevated, only, the levels of ALT, AST and cholesterol in male mice. A vigorous elevation in levels of different immunoglobulin (IgG, IgE and IgA) and pro-inflammatory cytokines (IL-6 and -8), that was accompanied by a significant reduction in level of anti-inflammatory cytokine IL-10, was observed in male and female mice groups administrated with sucralose or stevia. On the other hand, sucrose administration led to an elevation in IgA and reduction in IL-10 levels.

Neuroendocrine and Metabolic Effects of Low-Calorie and Non-Calorie Sweeteners

Since excessive sugar consumption has been related to the development of chronic metabolic diseases prevalent in the western world, the use of sweeteners has gradually increased worldwide over the last few years. Although low- and non-calorie sweeteners may represent a valuable tool to reduce calorie intake and prevent weight gain, studies investigating the safety and efficacy of these compounds in the short- and long-term period are scarce and controversial. Therefore, future studies will need to elucidate the potential beneficial and/or detrimental effects of different types of sweeteners on metabolic health (energy balance, appetite, body weight, cardiometabolic risk factors) in healthy subjects and patients with diabetes, obesity and metabolic syndrome. In this regard, the impact of different sweeteners on central nervous system, gut hormones and gut microbiota is important, given the strong implications that changes in such systems may have for human health. The aim of this narrative review is to summarize the current evidence for the neuroendocrine and metabolic effects of sweeteners, as well as their impact on gut microbiota. Finally, we briefly discuss the advantages of the use of sweeteners in the context of very-low calorie ketogenic diets.

Adaptation of the Gut Microbiota to Modern Dietary Sugars and Sweeteners

The consumption of sugar has become central to the Western diet. Cost and health concerns associated with sucrose spurred the development and consumption of other sugars and sweeteners, with the average American consuming 10 times more sugar than 100 y ago. In this review, we discuss how gut microbes are affected by changes in the consumption of sugars and other sweeteners through transcriptional, abundance, and genetic adaptations. We propose that these adaptations result in microbes taking on different metabolic, ecological, and genetic profiles along the intestinal tract. We suggest novel approaches to assess the consequences of these changes on host-microbe interactions to determine the safety of novel sugars and sweeteners.

Review of the scientific evidence and technical opinion on noncaloric sweetener consumption in gastrointestinal diseases

The present review of noncaloric sweeteners (NCSs) by the Asociación Mexicana de Gastroenterología was carried out to analyze and answer some of the most frequent questions and concerns about NCS consumption in patients with gastrointestinal disorders, through a thorough review of the medical literature. A group of gastroenterologists and experts on nutrition, toxicology, microbiology, and endocrinology reviewed and analyzed the published literature on the topic. The working group formulated conclusions, based on the scientific evidence published, to give an opinion with respect to NCS ingestion. Current evidence does not confirm the carcinogenic potential of NCSs. However, the studies analyzed showed that saccharin could have a proinflammatory effect and that polyols can cause gastrointestinal symptoms and manifestations, depending on the dose and type of compound. The ingestion of xylitol, erythritol, sucralose, aspartame, acesulfame K, and saccharin could increase the secretion of the gastrointestinal hormones that regulate intestinal motility, and stevia and its derivatives could have a favorable effect on the percentage of liver fat. Caution should be taken in recommending aspartame consumption in patients with chronic liver disease because it reduces the ratio of branched-chain amino acids to aromatic amino acids. In addition, NCS ingestion could modify the composition of the intestinal microbiota, having an effect on gastrointestinal symptoms and manifestations. It is important to continue conducting causality studies on humans to be able to establish recommendations on NSC consumption.

Altered in Vitro Metabolomic Response of the Human Microbiota to Sweeteners

Non-nutritive sweeteners represent an ingredient class that directly affects human health, via the development of inflammatory processes that promote chronic diseases related to microbiota dysbiosis. Several in vitro tests were conducted in the static GIS1 simulator. The aim of the study was to highlight the effect of sweeteners on the microbiota pattern of healthy individuals, associated with any alteration in the metabolomic response, through the production of organic acids and ammonium. The immediate effect of the in vitro treatment and the influence of the specific sweetener type on the occurrence of dysbiosis were evaluated by determining the biomarkers of the microbiota response. The presence of the steviol reduced the ammonium level (minimum of 410 mg/L), while the addition of cyclamate and saccharin caused a decrease in the number of microorganisms, in addition to lowering the total quantity of synthesized short-chain fatty acids (SCFAs). The bifidobacteria appeared to decrease below 10² genomes/mL in all the analyzed samples at the end of the in vitro simulation period. Barring the in vitro treatment of steviol, all the sweeteners tested exerted a negative influence on the fermentative profile, resulting in a decline in the fermentative processes, a rise in the colonic pH, and uniformity of the SCFA ratio.

Non-nutritive sweeteners possess a bacteriostatic effect and alter gut microbiota in mice

Non-nutritive sweeteners (NNSs) are widely used in various food products and soft drinks. There is growing evidence that NNSs contribute to metabolic dysfunction and can affect body weight, glucose tolerance, appetite, and taste sensitivity. Several NNSs have also been shown to have major impacts on bacterial growth both in vitro and in vivo. Here we studied the effects of various NNSs on the growth of the intestinal bacterium, E. coli, as well as the gut bacterial phyla Bacteroidetes and Firmicutes, the balance between which is associated with gut health. We found that the synthetic sweeteners acesulfame potassium, saccharin and sucralose all exerted strong bacteriostatic effects. We found that rebaudioside A, the active ingredient in the natural NNS stevia, also had similar bacteriostatic properties, and the bacteriostatic effects of NNSs varied among different Escherichia coli strains. In mice fed a chow diet, sucralose increased Firmicutes, and we observed a synergistic effect on Firmicutes when sucralose was provided in the context of a high-fat diet. In summary, our data show that NNSs have direct bacteriostatic effects and can change the intestinal microbiota in vivo.

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.

Fermented food in the context of a healthy diet: how to produce novel functional foods?

PURPOSE OF REVIEW

This review presents an overview of recent studies on the production of functional fermented foods, of both traditional and innovative natures, and the mapping of the functional compounds involved.

RECENT FINDINGS

The functional aspects of fermented foods are mostly related to the concept of probiotic bacteria or the targeted microbial generation of functional molecules, such as bioactive peptides, during food fermentation. Apart from conventional yoghurt and fermented milks, several fermented nondairy foods are globally gaining in interest, in particular from soy or cereal origin, sometimes novel but often originating from ethnic (Asian) diets. In addition, a range of functional nonmicrobial compounds may be added to the fermented food matrix. Overall, a wide variety of potential health benefits is being claimed, yet often poorly supported by mechanistic insights and rarely demonstrated with clinical trials or even animal models.

SUMMARY

Although functional foods offer considerable market potential, several issues still need to be addressed. As most of the studies on functional fermented foods are of a rather descriptive and preliminary nature, there is a clear need for mechanistic studies and well controlled in-vivo experiments.