Safety, feasibility, and impact on the gut microbiome of kefir administration in critically ill adults.

BACKGROUND: Dysbiosis of the gut microbiome is frequent in the intensive care unit (ICU), potentially leading to a heightened risk of nosocomial infections. Enhancing the gut microbiome has been proposed as a strategic approach to mitigate potential adverse outcomes. While prior research on select probiotic supplements has not successfully shown to improve gut microbial diversity, fermented foods offer a promising alternative. In this open-label phase I safety and feasibility study, we examined the safety and feasibility of kefir as an initial step towards utilizing fermented foods to mitigate gut dysbiosis in critically ill patients. METHODS: We administered kefir in escalating doses (60 mL, followed by 120 mL after 12 h, then 240 mL daily) to 54 critically ill patients with an intact gastrointestinal tract. To evaluate kefir's safety, we monitored for gastrointestinal symptoms. Feasibility was determined by whether patients received a minimum of 75% of their assigned kefir doses. To assess changes in the gut microbiome composition following kefir administration, we collected two stool samples from 13 patients: one within 72 h of admission to the ICU and another at least 72 h after the first stool sample. RESULTS: After administering kefir, none of the 54 critically ill patients exhibited signs of kefir-related bacteremia. No side effects like bloating, vomiting, or aspiration were noted, except for diarrhea in two patients concurrently on laxatives. Out of the 393 kefir doses prescribed for all participants, 359 (91%) were successfully administered. We were able to collect an initial stool sample from 29 (54%) patients and a follow-up sample from 13 (24%) patients. Analysis of the 26 paired samples revealed no increase in gut microbial α-diversity between the two timepoints. However, there was a significant improvement in the Gut Microbiome Wellness Index (GMWI) by the second timepoint (P = 0.034, one-sided Wilcoxon signed-rank test); this finding supports our hypothesis that kefir administration can improve gut health in critically ill patients. Additionally, the known microbial species in kefir were found to exhibit varying levels of engraftment in patients' guts. CONCLUSIONS: Providing kefir to critically ill individuals is safe and feasible. Our findings warrant a larger evaluation of kefir's safety, tolerability, and impact on gut microbiome dysbiosis in patients admitted to the ICU. TRIAL REGISTRATION: NCT05416814; trial registered on June 13, 2022.

Comparing Nutritional Values and Bioactivity of Kefir from Different Types of Animal Milk.

The growing interest in fermented dairy products is due to their health-promoting properties. The use of milk kefir grains as a starter culture made it possible to obtain a product with a better nutritional and biological profile depending on the type of milk. Cow, buffalo, camel, donkey, goat, and sheep milk kefirs were prepared, and the changes in sugar, protein, and phenol content, fatty acid composition, including conjugated linoleic acids (CLAs), as well as antioxidant activity, determined by ABTS and FRAP assays, were evaluated and compared. The protein content of cow, buffalo, donkey, and sheep milk increased after 24 h of fermentation. The fatty acid profile showed a better concentration of saturated and unsaturated lipids in all fermented milks, except buffalo milk. The highest content of beneficial fatty acids, such as oleic, linoleic, and C18:2 conjugated linoleic acid, was found in the cow and sheep samples. All samples showed a better antioxidant capacity, goat milk having the highest value, with no correlation to the total phenolic content, which was highest in the buffalo sample (260.40 ± 5.50 µg GAE/mL). These findings suggested that microorganisms living symbiotically in kefir grains utilize nutrients from different types of milk with varying efficiency.

Study and characterization of a product based on a vegetable extract of quinoa fermented with water kefir grains.

This work aimed to study and characterize a product based on vegetable extract of quinoa (WVEQ) fermented with water kefir grains. The effect of sucrose concentration (SC), inulin concentration (IC), and xanthan gum (XG) concentration were evaluated using a central composite design (CCD) 23. They were subsequently characterized regarding cellular growth of the grains, beverage yield, pH, soluble solids, carbon dioxide (CO2) production, lactic acid, and ethanol production. Therefore, for the final stage, two formulations (F1 and F8) of the CCD were chosen to be characterized in terms of proximate composition, microbiological composition of the kefir culture, analysis of organic compounds, sensory analysis, and enzymatic and microbiological characterization before and after simulation of in vitro gastrointestinal digestion. In the two chosen products, one can see that fermentation optimized the bioavailability of proteins due to the high proteolytic activity of the microorganisms in kefir and the increase in lipid content. In identifying microorganisms, there was a prevalence of Saccharomyces sp. yeasts. In the sensory analysis, the F8 formulation showed better results than the F1 formulation. In vitro, gastrointestinal digestion showed reduced lactic acid bacteria and yeast and increased acetic acid bacteria in the liquid phase for both formulations. In the enzymatic profile, there was a reduction in all enzymes analyzed for both formulations, except for amylase in F1, which went from 14.05 U/mL to 39.41 U/mL. Therefore, it is concluded that using WVEQ as a substrate for the product appears to be a viable alternative with nutritional and technological advantages for serving a specific market niche.

Water kefir: Factors affecting grain growth and health-promoting properties of the fermented beverage.

Nowadays, the interest in the consumption of healthy foods has increased as well as the homemade preparation of artisanal fermented product. Water kefir is an ancient drink of uncertain origin, which has been passed down from generation to generation and is currently consumed practically all over the world. Considering the recent and extensive updates published on sugary kefir, this work aims to shed light on the scientific works that have been published so far in relation to this complex ecosystem. We focused our review evaluating the factors that affect the beverage microbial and chemical composition that are responsible for the health attribute of water kefir as well as the grain growth. The microbial ecosystem that constitutes the grains and the fermented consumed beverage can vary according to the fermentation conditions (time and temperature) and especially with the use of different substrates (source of sugars, additives as fruits and molasses). In this sense, the populations of microorganisms in the beverage as well as the metabolites that they produce varies and in consequence their health properties. Otherwise, the knowledge of the variables affecting grain growth are also discussed for its relevance in maintenance of the starter biomass as well as the use of dextran for technological application.

Immunomodulatory Efficacy-Mediated Anti-HCV and Anti-HBV Potential of Kefir Grains; Unveiling the In Vitro Antibacterial, Antifungal, and Wound Healing Activities.

The utilization of fermented foods with health-promoting properties is becoming more popular around the world. Consequently, kefir, a fermented milk beverage made from kefir grains, was shown in numerous studies to be a probiotic product providing significant health benefits. Herein, we assessed the antibacterial and antifungal potential of kefir against a variety of pathogenic bacteria and fungi. This study also showed the effectiveness of kefir in healing wounds in human gastric epithelial cells (GES-1) by (80.78%) compared with control (55.75%) within 48 h. The quantitative polymerase chain reaction (qPCR) results of kefir-treated HCV- or HBV- infected cells found that 200 µg/mL of kefir can eliminate 92.36% of HCV and 75.71% of HBV relative to the untreated infected cells, whereas 800 µg/mL (the highest concentration) completely eradicated HCV and HBV. Moreover, the estimated IC50 values of kefir, at which HCV and HBV were eradicated by 50%, were 63.84 ± 5.81 µg/mL and 224.02 ± 14.36 µg/mL, correspondingly. Kefir can significantly suppress the elevation of TNF-α and upregulate IL-10 and INF-γ in both treated HCV- and HBV-infected cells. High-performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) analysis of kefir revealed the presence of numerous active metabolites which mainly contribute to the antimicrobial, antiviral, and immunomodulatory activities. This study demonstrated, for the first time, the anti-HBV efficacy of kefir while also illustrating the immunomodulatory impact in the treated HBV-infected cells. Accordingly, kefir represents a potent antiviral agent against both viral hepatitis C and B, as well as having antimicrobial and wound healing potential.

Determination of selenite and selenomethionine in kefir grains by reversed-phase high-performance liquid chromatography-inductively coupled plasma-optical emission spectrometry.

A new and efficient reversed-phase high-performance liquid chromatography-inductively coupled plasma-optical emission spectrometry method was developed for the simultaneous separation and determination of SeO3 2- and seleno-dl-methionine in kefir grains. For the system, limits of detection and quantitation values for SeO3 2- and seleno-dl-methionine were calculated as 0.52/1.73 mg/kg (as Se) and 0.26/0.87 mg/kg (as Se), respectively. After performing the system analytical performance, recovery experiment was done for kefir grains and percent recovery results for SeO3 2- and seleno-dl-methionine were calculated as 98.4 ± 0.8% and 93.6 ± 1.0%, respectively. It followed by the feeding studies that the kefir grains were exposed to three different concentrations of SeO3 2- (20, 30, and 50 mg/kg) for approximately 4 days at room temperature to investigate the conversion/non-conversion of SeO3 2- to seleno-dl-methionine. Next, the fed grains were extracted with tetramethylammonium hydroxide pentahydrate solution (20%, w/w) and then sent to the developed system. There was no detectable seleno-dl-methionine found in fed kefir grains at different concentrations of SeO3 2- while inorganic or elemental selenium in the fed kefir grains was determined between 1579.5 - 3116.0 mg/kg (as Se). Selenium species in the kefir grains samples was found in the form of SeO3 2- proved by using an anion exchange column.

Sheep milk kefir sweetened with different sugars: Sensory acceptance and consumer emotion profiling.

The objective of this study was to determine the sensory acceptance and emotional profile of sheep milk kefir sweetened with different sugars (demerara sugar, brown sugar, fructose, coconut sugar, and honey, 100 g/L). Consumers (n = 100) assessed sensory acceptance (appearance, aroma, taste, texture, and overall impression), and expressed their emotions (satisfied, active, loving, calm, comfortable, energetic, happy, healthy, refreshing, disgusted, worried, and upset). The emotions "satisfied," "active," "comfortable," "energetic," "healthy," and "refreshing" were found between moderate and very high levels, indicating that they are important emotions for the characterization and sensory acceptance of kefir samples. The use of different sugars had no influence on the intensity of the emotions "calm," "comfortable," "happy," or "disgusted," and resulted in a greater sense of satisfaction. The use of demerara sugar or fructose did not alter the acceptance of the products or the intensity of emotions. The use of brown sugar decreased acceptance (taste, texture, and overall impression) and the intensity of the emotions "active," "loving," "energetic," "healthy," and "refreshing." The use of coconut sugar decreased acceptance (appearance, aroma, and taste) and the intensity of the emotions "refreshing" and "upset." The use of honey improved acceptance in appearance and aroma but reduced the intensity of the emotions "active," "loving," "energetic," and "healthy." Based on sensory data, it is recommended to use demerara sugar or fructose as a substitute for sucrose. In conclusion, the study of emotions can be used as an additional tool for obtaining data related to the sensory acceptance of products.

Chemical Constitution and Antimicrobial Activity of Kefir Fermented Beverage.

Kefir beverage (KB) is a fermented milk initiated by kefir grains rich with starter probiotics. The KB produced in this study seemed to contain many chemical compounds elucidated by gas chromatography-mass spectrometry (GC-MS) and IR spectra. These compounds could be classified into different chemical groups such as alcohols, phenols, esters, fatty esters, unsaturated fatty esters, steroids, polyalkenes, heterocyclic compounds and aromatic aldehydes. Both KB and neutralized kefir beverage (NKB) inhibited some pathogenic bacteria including Escherichia coli ATCC11229 (E. coli), Listeria monocytogenes ATCC 4957 (L. monocytogenes), Bacillus cereus ATCC 14579 (B. cereus), Salmonella typhimurium ATCC 14028 (Sal. typhimurium) as well as some tested fungal strains such as Aspergillus flavus ATCC 16872 (A. flavus) and Aspergillus niger ATCC 20611 (A. niger), but the inhibitory activity of KB was more powerful than that obtained by NKB. It also appeared to contain four lactic acid bacteria species, one acetic acid bacterium and two yeast species. Finally, the KB inhibited distinctively both S. aureus and Sal. typhimurium bacteria in a brain heart infusion broth and in some Egyptian fruit juices, including those made with apples, guava, strawberries and tomatoes.

Microencapsulation of Bioactive Ingredients for Their Delivery into Fermented Milk Products: A Review.

The popularity and consumption of fermented milk products are growing. On the other hand, consumers are interested in health-promoting and functional foods. Fermented milk products are an excellent matrix for the incorporation of bioactive ingredients, making them functional foods. To overcome the instability or low solubility of many bioactive ingredients under various environmental conditions, the encapsulation approach was developed. This review analyzes the fortification of three fermented milk products, i.e., yogurt, cheese, and kefir with bioactive ingredients. The encapsulation methods and techniques alongside the encapsulant materials for carotenoids, phenolic compounds, omega-3, probiotics, and other micronutrients are discussed. The effect of encapsulation on the properties of bioactive ingredients themselves and on textural and sensory properties of fermented milk products is also presented.

Use of ultrafiltrated cow's whey for the production of whey cheese with Kefir or probiotics.

BACKGROUND: In Southern European countries, whey cheeses are normally produced with ovine or caprine whey. Cow's cheese whey can also be used, although the whey cheese yield is low (2-3%, w/v) which discourages its use. In the present study, bovine cheese whey was concentrated by ultrafiltration for the production of four types of whey cheeses (Requeijão): conventional, without any addition (WC); with 10% (w/w) addition of cream (WCC); with cream fermented with Kefir culture (WCCK); and with cream fermented with Bifidobacterium sp. culture (WCCBB12). RESULTS: Whey cheeses with cream presented lower protein content (330-360 g kg-1 , dry basis) and higher levels of total solids (220-250 g kg-1 ) and fat (300-330 g kg-1 , dry basis) than WC. C16:0 and C18:1 were the most abundant fatty acids present, with 31% and 38%, respectively. The small differences found concerning instrumental determination of colour and texture were not perceived by panelists. However, the presence of Kefir and probiotics decreased the elastic modulus (G') of the samples, as well as their viscosity. Fermentation with Kefir presented the highest counts of lactic acid bacteria (7 logUFC g-1 ). However, after 14 days of refrigerated storage, the counts of yeasts and moulds reached 6 logUFC g-1 in all products, indicating the need for appropriate packaging solutions. CONCLUSION: Ultrafiltration of bovine whey allows for the efficient production of bovine whey cheeses. The addition of cream fermented with Kefir or BB12 appears to be an efficient methodology to incorporate Kefir or probiotic bacteria in Requeijão, improving its nutritional and sensory characteristics, alongside the potential for the extension of its shelf-life. © 2020 Society of Chemical Industry.

Encapsulation of Russian Olive Water Kefir as an Innovative Functional Drink with High Antioxidant Activity.

Processing of Russian olive water kefir (RWK), as a fermented functional drink made with Russian olive juice and water kefir grains with high antioxidant activity, into powder is crucial for improving its stability for the commercialization of this product. For the first time, this study aimed to encapsulate water kefir microorganisms and bioactive compounds in RWK using carrier materials to develop a synbiotic functional powder using spray drying as an encapsulation method. The goal was maximizing antioxidant activity, product yield, and survival rate of water kefir microorganisms in the produced Russian olive water kefir powder. The optimal spray drying conditions were observed to be at an inlet air temperature of 120ºC, 35 % feed flow rate, and 7 % concentration of drying aid. The effects of spray drying conditions on the quality of microcapsules were assessed and modeled, and the validity of the model was verified. Also, the spray-dried powder's physicochemical properties were assessed and showed promising microbial and physicochemical characteristics compared with the freeze-dried powder.

Short communication: Effect of different kefir grains on the attributes of kefir produced with milk from Costa Rica.

Kefir is an artisanal product that is gaining scientific attention due to its increase in consumption attributed to its potential health benefits. The effect on the quality attributes of kefir grains of different origin (household and commercial) and preserved with different methods (drying and freezing) was evaluated to standardize a domestic and semi-industrial process. Chemical (protein, lactose. lactic acid, ethanol, and acetic acid) as well as microbial properties (total plate count and total yeast count) were monitored during the experiment. Results show a statistical difference between the kefir grains in terms of acetic acid and ethanol percentages, which leads to the conclusion that there is a difference in the microbial populations that produce these products. Lactic acid, protein, and lactose parameters are statistically the same as well as the growth in biomass and the total population of yeast. Our results suggest that both types of kefir grains maintain a similar performance and that their metabolic capabilities are stable throughout time (taking into account that the household grains have been productive for years), meaning that domestic or semi-industrial processes could be easily standardized.

The Effect of Fermentation with Kefir Grains on the Physicochemical and Antioxidant Properties of Beverages from Blue Lupin (Lupinus angustifolius L.) Seeds.

Plant derived fermented beverages have recently gained consumers' interest, particularly due to their intrinsic functional properties and presence of beneficial microorganisms. Three variants containing 5%, 10%, and 15% (w/w) of sweet blue lupin (Lupinus angustifolius L. cv. "Boregine") seeds were inoculated with kefir grains and incubated at 25 °C for 24 h. After processing, beverages were stored in refrigerated conditions (6 °C) for 21 days. Changes in microbial population, pH, bioactive compounds (polyphenolics, flavonoids, ascorbic acid), reducing sugars, and free amino acids were estimated. Additionally, viscosity, firmness, color, and free radicals scavenging properties were determined. Results showed that lactic acid bacteria as well as yeast were capable of growing well in the lupin matrix without any supplementation. During the process of refrigeration, the viability of the microorganisms was over the recommended minimum level for kefir products. Hydrolysis of polysaccharides as well as increase of free amino acids was observed. As a result of fermentation, the beverages showed excellent DPPH, ABTS+·, ·OH, and O2- radicals scavenging activities with a potential when considering diseases associated with oxidative stress. This beverages could be used as a new, non-dairy vehicle for beneficial microflora consumption, especially by vegans and lactose-intolerant consumers.

Effect of Addition of Pectins from Jujubes (Ziziphus jujuba Mill.) on Vitamin C Production during Heterolactic Fermentation.

Soluble fibers, including pectins from apple and lemon, are commonly used as prebiotic and to prepare functional foods. The present study aimed to investigate the physicochemical and functional properties of pectins extracted from jujubes (Ziziphus jujuba Mill.). Pectins were extracted from jujubes at three stages of harvesting and characterized by FTIR and SEM analyses. Whole milk inoculated with kefir grains was supplemented by 0.25 mg·mL-1 of pectins. The pH value and vitamin C content were evaluated after 24 and 48 h of fermentation. Pectins from jujubes at the first harvesting stage (PJ1K) showed the lowest methoxylation degree. The addition of pectins enhanced the production of vitamin C during heterolactic process. This result was found to depend on jujube harvesting stage as PJ1K stimulated the growth of yeasts in kefir grains yielding to the highest amount of vitamin C (0.83 ± 0.01 µg·mL-1) compared to other samples (0.53-0.60 µg·mL-1) at 24 h. Lactic acid bacteria diminish pH rapidly with respect to control (4.13 ± 0.05), according to the stage of maturation, reducing its initial value by 38.3% in PJ1K. Besides being an excellent prebiotic, pectins from jujubes could be used to enrich kefir with vitamin C.

Freeze-dried immobilized kefir culture in cider-making.

BACKGROUND: The aim of the present study was to evaluate the fermentation efficiency of freeze-dried immobilized kefir culture on natural supports (apple pieces, delignified cellulosic material) in cider making at various temperatures (5-45 °C) in comparison with freeze-dried free cells. Freeze-dried cells were initially tested in apple juice fermentations at 30 °C, and then the freeze-dried cultures produced with no cryoprotectants were assessed in repeated batch fermentations. RESULTS: Repeated batch fermentations lasted for longer than 5 months. High malic acid conversion rates (up to 78.5%) and ethanol productivity values (up to 37.9 g L-1 day-1 ) were recorded for freeze-dried immobilized cells. Polymerase chain reaction - denaturing gradient gel electrophoresis (PCR-DGGE) analysis showed that freeze-drying had no effect on the microbial diversity of kefir culture. Higher alcohols were significantly reduced at low fermentation temperatures. Application of principal component analysis (PCA) revealed that both the fermentation temperature and the nature of the freeze-dried kefir culture affected significantly the minor volatiles determined by gas chromatography/mass spectrometry (GC/MS). Notably, all ciders produced were of high quality and were accepted by the tasting panel. CONCLUSIONS: Freeze-dried immobilized kefir culture on natural supports with no cryoprotectants was found to be suitable for simultaneous alcoholic and malolactic cider fermentation at various temperatures (5-45 °C). The high operational stability of the systems was confirmed and the results obtained are of great interest for the industrial sector as they could be exploited for cider, low-alcohol cider, or 'soft' cider production. © 2020 Society of Chemical Industry.

Kefir micro-organisms: their role in grain assembly and health properties of fermented milk.

Kefir is a homemade viscous and slightly effervescent beverage obtained by milk fermentation with kefir grains, which are built up by a complex community of lactic acid and acetic acid bacteria and yeasts confined in a matrix of proteins and polysaccharides. The present review summarizes the role of kefir micro-organisms in grain assembly and in the beneficial properties attributed to kefir. The use of both culture-dependent and independent methods has made possible to determine the micro-organisms that constitute this ecosystem. Kefir consumption has been associated with a wide range of functional and probiotic properties that could be attributed to the micro-organisms present in kefir and/or to the metabolites synthetized by them during milk fermentation. In this context, the role of micro-organisms in kefir health promoting properties is discussed with particular attention to the contribution of yeast as well as bioactive metabolites such as lactic and acetic acid, exopolysaccharides and bioactive peptides. Even though many advances on the knowledge of this ancient fermented milk have been made, further studies are necessary to elucidate the complex nature of the kefir ecosystem.

In situ riboflavin fortification of different kefir-like cereal-based beverages using selected Andean LAB strains.

Cereal-based functional beverages represent social, economic, and environmental sustainable opportunities to cope with emerging trends in food consumption and global nutrition. Here we report, for the first time, the polyphasic characterization of three cereal-based kefir-like riboflavin-enriched beverages, obtained from oat, maize and barley flours, and their comparison with classical milk-based kefir. The four matrices were successfully fermented with commercial starters: i) milk-kefir and ii) water-kefir, proving the potential of cereal ingredients in the formulation of dairy-like fermented beverages with milk-kefir starter behavior better in these matrices. In the light of their potentiality, seven riboflavin-producing Andean Lactic Acid Bacteria (LAB) were tested for tolerance to food stresses commonly encountered during food fermentation. Moreover, the LAB strains investigated were screened for spontaneous riboflavin overproducing derivatives. Lactobacillus plantarum M5MA1-B2 with outstanding response to stress, was selected to improve riboflavin content in an in situ fortification approach. The combination of L. plantarum M5MA1-B2 riboflavin overproducing strain with milk kefir starter in oat, lead to cover, for one serving of 100 g, 11.4% of Recommended Dietary Allowance (RDA). Besides, addition of L. plantarum M5MA1-B2 improved performance of water kefir in oat and maize matrices. Proton Transfer Reaction Time-of-Flight Mass Spectrometry (PTR-ToF-MS) analysis provided the on-line Volatile Organic Compounds profiles supporting the best combination of starter, LAB and cereal matrix for novel functional foods development.

Comparative in vitro efficacy of kefir produced from camel, goat, ewe and cow milk on Haemonchus contortus.

One of the great challenges of veterinary parasitology is the search for alternative methods for controlling gastrointestinal parasites in small ruminants. Milk kefir is a traditional source of probiotic, with great therapeutic potential. The objective of this study was to investigate the anthelmintic effects of kefir on the abomasal nematode Haemonchus contortus from sheep. The study used camel, goat, ewe and cow milk as a starting material, to produce camel, goat, cow and ewe milk kefir. All kefirs showed a significant concentration-dependent effect on H. contortus egg hatching at all tested concentrations. The highest inhibition (100%) of eggs was observed with camel milk kefir at a concentration 0.125 mg/ml. In relation to the effect of kefirs on the survival of adult parasites, all kefirs induced concentration-dependent mortality in adults, with variable results. The complete mortality (100%) of adults of H. contortus occurred at concentrations in the range 0.25-2 mg/ml. The highest inhibition of motility (100%) of worms was observed after 8 h post exposure with camel milk kefir at 0.25 mg/ml. These findings indicate that kefir can be considered a potential tool to control haemonchosis in sheep. Further investigations are needed to assess the active molecules in kefir responsible for its anthelmintic properties and to investigate similar in vivo effects.

Mechanisms of Action of Kefir in Chronic Cardiovascular and Metabolic Diseases.

The gut microbiota maintains a complex mutual interaction with different organs of the host. Whereas in normal conditions this natural community of trillions of microorganisms greatly contributes to the human health, gut dysbiosis is related with onset or worsening of diverse chronic systemic diseases. Thus, the reestablishment of gut microbiota homeostasis with consumption of prebiotics and probiotics may be a relevant strategy to prevent or attenuate several cardiovascular and metabolic complications. Among these functional foods, the synbiotic kefir, which is a fermented milk composed of a mixture of bacteria and yeasts, is currently the most used and has attracted the attention of health care professionals. The present review is focused on reports describing the feasibility of kefir consumption to provide benefits in cardiometabolic diseases, including hypertension, vascular endothelial dysfunction, dyslipidemia and insulin resistance. Interestingly, recent studies show that mechanisms of actions of kefir in cardiometabolic diseases include recruitment of endothelial progenitor cells, improvement of the balance vagal/sympathetic nervous system, diminution of excessive generation of reactive oxygen species, angiotensin converting enzyme inhibition, anti-inflammatory cytokines profile and alteration of the intestinal microbiota. These findings provide a better understanding about the mechanisms of the beneficial actions of kefir and motivate further investigations to determine whether the use of this synbiotic could also be translated into clinical improvements in cardiometabolic diseases.

Oxygen and diverse nutrients influence the water kefir fermentation process.

Eight water kefir fermentation series differing in the presence of oxygen, the nutrient concentration, and the nutrient source were studied during eight consecutive backslopping steps. The presence of oxygen allowed the proliferation of acetic acid bacteria, resulting in high concentrations of acetic acid, and decreased the relative abundance of Bifidobacterium aquikefiri. Low nutrient concentrations resulted in slow water kefir fermentation and high pH values, which allowed the growth of Comamonas testosteroni/thiooxydans. Further, low nutrient concentrations favored the growth of Lactobacillus hilgardii and Dekkera bruxellensis, whereas high nutrient concentrations favored the growth of Lactobacillus nagelii and Saccharomyces cerevisiae. Dried figs, dried apricots, and raisins resulted in stable water kefir fermentation. Water kefir fermentation with dried apricots resulted in the highest pH and water kefir grain growth, whereas that with raisins resulted in the lowest pH and water kefir grain growth. Further, water kefir fermentation with raisins resembled fermentations with low nutrient concentrations, that with dried apricots resembled fermentations with normal nutrient concentrations, and that with fresh figs or a mixture of yeast extract and peptone resembled fermentations with high nutrient concentrations.