Yogurt and gut function

Effect of Lactiplantibacillus plantatum HFY11 on Colitis in Mice

This study aimed to examine the potential impact of the intervention of Lactiplantibacillus plantatum HFY11 (LP-HFY11) on colitis using in vivo animal trials. The impact of LP-HFY11 intervention on colitis was determined by measuring the levels of relevant indicators in the intestine, colon, and blood after oxazolone-induced colitis in BALB/c mice. The results of the trial show that LP-HFY11 improved the colon weight-to-length ratio, reduced the colitis-induced colon length shortening, and reduced colonic abstinence. Furthermore, it decreased the levels of myeloperoxidase, nitric oxide, and malondialdehyde activities while increasing the glutathione content in the colon tissue of colitis-affected animals. LP-HFY11 lowered the interleukin-10 (IL-10) level and increased the IL-2 level in the serum of colitis mice. LP-HFY11 also upregulated the expression of neuronal nitric oxide synthase, endothelial nitric oxide synthase, c-Kit, and stem cell factor (SCF), and downregulated the expression of IL-8, C-X-C chemokine receptor type 2 (CXCR2), and inducible nitric oxide synthase (iNOS) in the colon tissue of mice with colitis. LP-HFY11 decreased the expression of Firmicutes in the gut while increasing the expression of Bacteroidetes, Bifidobacteria, and Lactobacillus. This indicates that LP-HFY11 could control physiological alterations in the serum and colon tissue, as well as the expression of gut microorganism.

Silk-derived sericin/fibroin mixture drink fermented with plant-derived Lactococcus lactis BM32-1 improves constipation and related microbiota: a randomized, double-blind, and placebo-controlled clinical trial

We previously showed through clinical trials that one plant-derived lactic acid bacteria (LAB) can improve constipation. We preliminarily found that the plant-derived LAB Lactococcus lactis BM32-1 can grow in a mixture of sericin and fibroin, which are extracted from silk and have been reported to help promote health. Thus, in the present study, we evaluated the favorable effect of a sericin/fibroin mixture (S/F-M), which was extracted from silk prepared from cocoons reared in an aseptic rearing system using an artificial diet, fermented with the BM32-1 strain through a clinical trial. The trial was conducted at Hiroshima University from June to October 2022 as a double-blind, placebo-controlled, randomized parallel-group comparative study with 50 eligible subjects (aged 23-71) who had an average defecation frequency of less than 5 times per week. The subjects were instructed to drink 100 mL of fermented S/F-M or placebo every day. After the 12 weeks of the clinical trial period, the average defecation frequency increased significantly-1.4 times higher than that at baseline in the test group-as compared with the placebo group. Furthermore, the fecal microbiota was also compared before and after treatment, revealing that intake of the fermented S/F-M significantly multiplied the relative abundance of the genera Enterococcus and Clostridium, which have been reported to contribute to the amelioration of constipation by improving the gut microbiota and producing butyric acid, respectively. In conclusion, the S/F-M fermented using the BM32-1 strain improves defecation frequency through alteration of the gut microbiota.

The inhibition effects of Lentilactobacillus buchneri-derived membrane vesicles on AGS and HT-29 cancer cells by inducing cell apoptosis

In recent years, probiotics and their derivatives have been recognized as important therapeutic agents in the fight against cancer. Therefore, this study aimed to investigate the anticancer effects of membrane vesicles (MVs) from Lentilactobacillus buchneri strain HBUM07105 probiotic isolated from conventional and unprocessed yogurt in Arak province, Iran, against gastric and colon cancer cell lines. The MVs were prepared from the cell-free supernatant (CFS) of L. buchneri and characterized using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) and SPS-PAGE techniques. The anticancer activity of MVs was evaluated using MTT, flow cytometry, qRT-PCR techniques, and a scratch assay. The study investigated the anti-adenocarcinoma effect of MVs isolated from L. buchneri on a human gastric adenocarcinoma cell line (AGS) and a human colorectal adenocarcinoma cell line (HT-29) at 24, 48, and 72-h time intervals. The results demonstrated that all prepared concentrations (12.5, 25, 50, 100, and 200 µg/mL) of MVs reduced the viability of both types of human adenocarcinoma cells after 24, 48, and 72 h of treatment. The analysis of the apoptosis results revealed that the percentage of AGS and HT-29 cancer cells in the early and late stages of apoptosis was significantly higher after 24, 48, and 72 h of treatment compared to the untreated cancer cells. After treating both AGS and HT-29 cells with the MVs, the cells were arrested in the G0/G1 phase. These microvesicles demonstrate apoptotic activity by increasing the expression of pro-apoptotic genes (BAX, CASP3, and CASP9). According to the scratch test, MVs can significantly decrease the migration of HT-29 and AGS cancer cells after 24, 48, and 72 h of incubation compared to the control groups. The MVs of L. buchneri can also be considered a potential option for inhibiting cancer cell activities.

Effects of Panax notoginseng Saponins Encapsulated by Polymerized Whey Protein on the Rheological, Textural and Bitterness Characteristics of Yogurt

Panax notoginseng saponins (PNSs) have been used as a nutritional supplement for many years, but their bitter taste limits their application in food formulations. The effects of PNS (groups B, C, and D contained 0.8, 1.0 and 1.2 mg/mL of free PNS, respectively) or Panax notoginseng saponin-polymerized whey protein (PNS-PWP) nanoparticles (groups E, F, and G contained 26.68, 33.35 and 40.03 mg/mL of PNS-PWP nanoparticles, respectively) on the rheological, textural properties and bitterness of yogurt were investigated. Group G yogurt showed a shorter gelation time (23.53 min), the highest elastic modulus (7135 Pa), higher hardness (506 g), higher apparent viscosity, and the lowest syneresis (6.93%) than other groups, which indicated that the yogurt formed a stronger gel structure. The results of the electronic tongue indicated that the bitterness values of group E (-6.12), F (-6.56), and G (-6.27) yogurts were lower than those of group B (-5.12), C (-4.31), and D (-3.79), respectively, which might be attributed to PNS being encapsulated by PWP. The results indicated that PWP-encapsulated PNS could cover the bitterness of PNS and improve the quality of yogurt containing PNS.

Research Progress for Probiotics Regulating Intestinal Flora to Improve Functional Dyspepsia: A Review

Functional dyspepsia (FD) is a common functional gastrointestinal disorder. The pathophysiology remains poorly understood; however, alterations in the small intestinal microbiome have been observed. Current treatments for FD with drugs are limited, and there are certain safety problems. A class of active probiotic bacteria can control gastrointestinal homeostasis, nutritional digestion and absorption, and the energy balance when taken in certain dosages. Probiotics play many roles in maintaining intestinal microecological balance, improving the intestinal barrier function, and regulating the immune response. The presence and composition of intestinal microorganisms play a vital role in the onset and progression of FD and serve as a critical factor for both regulation and potential intervention regarding the management of this condition. Thus, there are potential advantages to alleviating FD by regulating the intestinal flora using probiotics, targeting intestinal microorganisms. This review summarizes the research progress of probiotics regarding improving FD by regulating intestinal flora and provides a reference basis for probiotics to improve FD.

Milk and dairy product intakes, intestinal bacteria, and respiratory infections in children of elementary school age and older in Japan

OBJECTIVES

The aim of this study was to examine the associations between milk and dairy product intakes, intestinal bacteria, and respiratory infections in children of elementary school age and older in Japan.

METHODS

We conducted cross-sectional surveys each year from 2013 to 2015 for grades 2, 5, and 8 students of an elementary and junior high school (n = 1020). Exclusion owing to ineligibility regarding data on dietary intake, respiratory infections, and intestinal bacteria led to 922 participants for the analyses. Dietary intake was assessed with a self-administered food frequency questionnaire. Respiratory infections occurring ≥ 4 episodes over the past year were determined based on the caregivers' reports. Intestinal bacteria (species and counts) were analyzed with real-time polymerase chain reaction. Logistic regression models were used to estimate the odds ratios (ORs) and 95% CIs.

RESULTS

The odds of ≥ 4 respiratory infection episodes decreased with higher milk intake after adjusting for potential confounders, and the ORs (95% CIs) for the second and third tertile categories, compared with the first tertile category, were 0.91 (0.58-1.42) and 0.48 (0.29-0.77), respectively (P for trend = 0.001). A decreasing trend in the ORs for lactic acid drink intake was observed only in those with a low count of intestinal Faecalibacterium prausnitzii.

CONCLUSIONS

We found that higher milk intake was inversely associated with respiratory infections in children older than preschool age. Higher lactic acid drink intake could be inversely associated only in children with a low F. prausnitzii count in the intestine.

Application of natural and modified additives in yogurt formulation: types, production, and rheological and nutraceutical benefits

Yogurt, a popular fermented dairy product, is of different types and known for its nutritional and nutraceutical benefits. However, incorporating additives into yogurt has been adopted to improve its functionality and nutraceutical properties. Additives incorporated in yogurt may be natural or modified. The incorporation of diverse natural additives in yogurt formulation, such as moringa, date palm, grape seeds and argel leaf extracts, cornelian cherry paste, mulberry fruit and leaf powder, lentil flour, different types of fibers, lemongrass and spearmint essential oils, and honey, has been reported. Similarly, modified additives, such as β-glucan, pectin, inulin, sodium alginate, and gelatin, are also added to enhance the physicochemical, textural, sensory, and rheological properties of yogurt. Although additives are traditionally added for their technological impact on the yogurt, studies have shown that they influence the nutritional and nutraceutical properties of yogurt, when added. Hence, yogurts enriched with functional additives, especially natural additives, have been reported to possess an improved nutritional quality and impart several health benefits to consumers. These benefits include reducing the risk of cardiovascular disease, cancer, osteoporosis, oxidative stress, and hyperglycemia. This current review highlights the common types of yogurt, the production process, and the rheological and nutraceutical benefits of incorporating natural and modified additives into yogurt.

Influences of Yogurt with Functional Ingredients from Various Sources That Help Treat Leaky Gut on Intestinal Barrier Dysfunction in Caco-2 Cells

The impact of yogurts made with starter culture bacteria (L. bulgaricus and S. thermophilus) and supplemented with ingredients (maitake mushrooms, quercetin, L-glutamine, slippery elm bark, licorice root, N-acetyl-D-glucosamine, zinc orotate, and marshmallow root) that can help treat leaky gut were investigated using the Caco-2 cell monolayer as a measure of intestinal barrier dysfunction. Milk from the same source was equally dispersed into nine pails, and the eight ingredients were randomly allocated to the eight pails. The control had no ingredients. The Caco-2 cells were treated with isoflavone genistein (negative control) and growth media (positive control). Inflammation was stimulated using an inflammatory cocktail of cytokines (interferon-γ, tumor necrosis factor-α, and interleukin-1β) and lipopolysaccharide. The yogurt without ingredients (control yogurt) was compared to the yogurt treatments (yogurts with ingredients) that help treat leaky gut. Transepithelial electrical resistance (TEER) and paracellular permeability were measured to evaluate the integrity of the Caco-2 monolayer. Transmission electron microscopy (TEM), immunofluorescence microscopy (IM), and real-time quantitative polymerase chain reaction (RTQPCR) were applied to measure the integrity of tight junction proteins. The yogurts were subjected to gastric and intestinal digestion, and TEER was recorded. Ferrous ion chelating activity, ferric reducing potential, and DPPH radical scavenging were also examined to determine the yogurts' antioxidant capacity. Yogurt with quercetin and marshmallow root improved the antioxidant activity and TEER and had the lowest permeability in fluorescein isothiocyanate (FITC)-dextran and Lucifer yellow flux among the yogurt samples. TEM, IM, and RTQPCR revealed that yogurt enhanced tight junction proteins' localization and gene expression. Intestinal digestion of the yogurt negatively impacted inflammation-induced Caco-2 barrier dysfunction, while yogurt with quercetin, marshmallow root, maitake mushroom, and licorice root had the highest TEER values compared to the control yogurt. Yogurt fortification with quercetin, marshmallow root, maitake mushroom, and licorice root may improve functionality when dealing with intestinal barrier dysfunction.

Physicochemical, Rheological, and Sensory Characteristics of Yogurt Fermented by Lactic Acid Bacteria with Probiotic Potential and Bioprotective Properties

The applicability of two lactic acid bacterial strains with probiotic potential and bioprotective properties as additions in the starter culture in yogurt fermentation was examined. The studied strains, Lactobacillus delbrueckii subsp. bulgaricus KZM 2-11-3 and Lactiplantibacillus plantarum KC 5-12, inhibited the growth of Kluyveromyces lactis, Kluyveromyces marxianus, and Saccharomyces cerevisiae. The strain L. delbrueckii subsp. bulgaricus KZM 2-11-3 directly inhibited Escherichia coli. The important characteristics for the quality of the yogurt product, such as physicochemical parameters during fermentation and storage, rheological characteristics, and sensory changes during the storage of samples were determined. The yogurt samples with the strains did not differ in most parameters from the control yogurt with the commercial starter. The added strains showed stable viability in the yogurt samples during storage. The yogurt sample with L. delbrueckii subsp. bulgaricus KZM 2-11-3 and the sample with both strains based on the total evaluation were very similar to the control yogurt with the commercial starter. Using these strains as probiotic supplements to enrich the starter cultures in yogurt production will contribute to developing new products with benefits to human health.

Inulin increases the EPS biosynthesis of Lactobacillus delbrueckii ssp. bulgaricus LDB-C1

OBJECTIVE

Its eps gene cluster, the antioxidant activity and monosaccharide composition of exopolysaccharides, the expression levels of related genes at different fermentations were analyzed for clarifying the exopolysaccharide biosynthesis mechanism of Lactobacillus delbrueckii subsp. bulgaricus LDB-C1.

RESULTS

The comparison analysis of eps gene clusters indicated that the gene clusters present diversity and strain specificity. The crude exopolysaccharides from LDB-C1 exhibited a good antioxidant activity. Compared with glucose, fructose, galactose, and fructooligosaccharide, inulin significantly improved the exopolysaccharide biosynthesis. The structures of EPSs were significantly different under different carbohydrate fermentation conditions. Inulin obviously increased the expressions of most EPS biosynthesis related genes at fermentation 4 h.

CONCLUSION

Inulin accelerated the beginning of the exopolysaccharide production in LDB-C1, and the enzymes promoted by inulin was beneficial for the accumulation of exopolysaccharide at the whole fermentation process.

Deep Shotgun metagenomic and 16S rRNA analysis revealed the microbial diversity of lactic acid bacteria in traditional fermented foods of eastern Hainan, China

The eastern part of Hainan, China, has a flat terrain and a suitable climate with abundant sunshine and rain. This unique environment makes the tropical microbial resources of natural fermented food unique and rich. Therefore, we combined Shotgun metagenomic sequencing, 16S rRNA sequencing and pure culture technology to analyze the microbial diversity, microbiota composition, species differences and correlation of 30 traditional fermented food samples collected from Wenchang, Qionghai, Wanning and Lingshui in the eastern part of Hainan province, and isolated, identified and preserved the microorganisms in them. The results showed that the microbial community structure differs significantly between samples from different regions and between different substrates. The alpha diversity of microorganisms in traditional fermented foods in the Wanning area was higher than those of the other three areas. The beta diversity indicated that the microbiota structural difference between Wanning and Qionghai was smaller. This is consistent with the fact that the precipitation in the Wanning area is the highest and similar to that of Qionghai. The alpha diversity of microorganisms was the highest in fermented vegetables, followed by fermented grains, and the lowest in fermented seafood. Beta diversity showed that the microbiota composition of fermented grains and fermented vegetables is very similar, but that of fermented seafood is significantly different. The results of microbiota structural analysis showed that firmicutes and proteobacteria are the dominant bacterial phyla, and Lactobacillus plantarum and Lactobacillus fermentum are the dominant species in traditional fermented foods in eastern Hainan. Lactic acid bacteria are the dominant species in traditional fermented foods from the eastern Hainan region of China, regardless of the substrate used in fermentation. According to the microbial functional characteristics, the microbial metabolism and biosynthesis pathways in traditional fermented foods in Hainan tend to be active. In addition, combined with pure culture technology, we isolated, identified and preserved 342 lactic acid bacteria strains from traditional fermented food in eastern Hainan province. This study helped us understand the different characteristics of microbial communities in tropical southern China and supplement the Lactobacillus species resource pool in tropical southern China. Moreover, it provided new insights and directions for the development and utilization of fermented foods.

The gut microbiome: an overview of current trends and risks for paediatric populations

PURPOSE OF REVIEW

Gut health is an increasingly popular topic of discussion among scientists and the general population alike. As interest surrounding the gut microbiome grows, the accessibility to misinformation and unfounded gut health trends to youth is likely to emerge as a public health concern. The purpose of this review is to provide paediatricians with current information about the gut microbiome, as well as explanations and possible risks of the multitude of gut health trends that adolescents may be exposed to.

RECENT FINDINGS

The gut microbiome is implicated in overall health by playing roles in digestion, immunity and mental health. Novel microbiome-related therapies, such as faecal microbiota transplants, and the gut-brain link show the therapeutic potential of the gut microbiome. However, unproven dietary fads and trends on social media are rampant as well, such as ginger juice shots. In addition, paediatric supplements meant to target gut health are unregulated, yet are highly marketed. Improperly applying these trends and diets may result in risks of malnutrition and body image issues for impressionable children.

SUMMARY

Increased familiarity regarding the types of gut health trends and diets among young people will allow paediatricians to more effectively advise their patients about potential risks and good gut health practices. Paediatricians and caregivers serve as role models and educators with regard to children's perceptions and management of their gut and overall health.

Approaches to nutrition intervention in plaque psoriasis, a multi-system inflammatory disease-The Diet and Psoriasis Project (DIEPP)

Psoriasis is an immune-mediated inflammatory skin disease affecting approximately 2% of the UK population. Its pathogenesis is suggested to be an outcome of genetic and environmental interplay. People with psoriasis have an increased likelihood of developing other conditions such as type 2 diabetes and cardiovascular disease. Systemic inflammation is hypothesised to be the common link between psoriasis and cardio-metabolic diseases. Emerging evidence shows diet as a potential therapeutic adjunct in the management of psoriasis. The Diet and Psoriasis Project (DIEPP) aims to investigate whether dietary factors are related to psoriasis severity by conducting an observational study followed by a dietary intervention trial, to assess the effect of the Mediterranean diet (MedD) and time-restricted eating (TRE) on psoriasis. This review article will explore the potential mechanisms by which the MedD and TRE may exert protective effects on psoriasis, evaluate the current evidence, and outline the design of the DIEPP. Given the early-stage evidence, we hope to be able to build knowledge to derive medically approved dietary recommendations and contribute to the research gaps exploring the role of diet and psoriasis.

Plant-Derived Lactobacillus paracasei IJH-SONE68 Improves the Gut Microbiota Associated with Hepatic Disorders: A Randomized, Double-Blind, and Placebo-Controlled Clinical Trial

Our previous clinical study has shown that the exopolysaccharide (EPS) produced by a plant-derived lactic acid bacterium, Lactobacillus paracasei IJH-SONE68, improves chronic allergy status in humans. In addition, an inhibition of visceral fat accumulation was observed following the intake of EPS during animal experimentation. In the present study, we have further evaluated the health-promoting effects of a spray-dried powder of pineapple juice that is fermented with the IJH-SONE68 strain. This was conducted in a double-blind, randomized, placebo-controlled, parallel-group clinical trial at Hiroshima University from May 2019 to July 2021. Eighty healthy volunteers at range of ages 23-70, with a body mass index between 25 and 29.99, were enrolled. After the 12 weeks of the experimental period were complete, although the average visceral fat area in both groups similarly decreased, there was no significant difference in the content of visceral fat area or in the obesity-related physical parameters in both groups. Further, we found that the serum liver function indices (AST and ALT) in the test group decreased within a statistically determined trend (p = 0.054). The fecal microflora analysis revealed, in the test group, a statistically significant increase in the relative abundance changes within Anaerostipes, which has been reported to help suppress hepatic inflammation.

Beneficial Effects of Yoghurts and Probiotic Fermented Milks and Their Functional Food Potential

Probiotic fermented milks and yoghurts are acidified and fermented by viable bacteria, usually L. bulgaricus and S. thermophilus, resulting in a thicker product with a longer shelf life. They are a nutrition-dense food, providing a good source of calcium, phosphorus, potassium, vitamin A, vitamin B2, and vitamin B12. Additionally, they deliver high biological value proteins and essential fatty acids. There is accumulating evidence suggesting that yoghurt and fermented milk consumption is related to a number of health advantages, including the prevention of osteoporosis, diabetes, and cardiovascular diseases, as well as the promotion of gut health and immune system modulation. This review aims at presenting and critically reviewing the beneficial effects from the consumption of probiotic fermented milks in human health, whilst revealing potential applications in the food industry.

Physicochemical, functional and sensory properties of probiotic yoghurt flavored with white sapote fruit (Casimiroa edulis)

Yoghurt is one of the health-functional foods and its nutritive value can be enhanced by adding native fruit. This study aimed to produce novel functional probiotic yoghurt using Bifidobacterium longum (B. longum) strain and White sapote fruits pulp (WSP) at levels of 5, 10, and 15%. WSP contains 19.87% carbohydrates, 0.90% protein, 0.35% fat, 0.78% fiber, 0.6% ash, 48.70 (mg GAE/100 g) total phenolic, 28.25 (mg/100 g) ascorbic acid and 153.53 (IC50 (mg/mL)) for antioxidant activity. Physicochemical, microbiological and sensory evaluation of flavored yoghurt samples were investigated during storage at 5 ± 1 °C for 21 days. The results revealed that increases in total solids, protein, ash, and carbohydrates content were observed in the flavored probiotic yoghurt compared to the control sample. Syneresis and WHC values of flavored yoghurt were influenced by supplementation with WSP whether in fresh or stored samples. Furthermore, significant (P< 0.05) increases in ascorbic acid, antioxidant activity, total phenols, vitamins, and minerals were observed in flavored probiotic yoghurt. Molds & yeast were not detected in all samples except in both control and probiotic yoghurt samples that appeared after 14 and 21 days. Similarly, coliforms were not found in all fresh and stored yoghurt samples. Sensory evaluation results showed that probiotic yoghurt flavored with 10% WSP had the highest acceptance scores compared to other treatments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-022-05393-5.

Modulating Gene Expression within a Microbiome Based on Computational Models

Simple Summary

Development of computational biology methodologies has provided comprehensive understanding of the complexity of microbiomes, and the extensive ways in which they influence their environment. This has awakened a new research goal, aiming to not only understand the mechanisms in which microbiomes function, but to actively modulate and engineer them for various purposes. However, current microbiome engineering techniques are usually manually tailored for a specific system and neglect the different interactions between the new genetic information and the bacterial population, turning a blind eye to processes such as horizontal gene transfer, mutations, and other genetic alterations. In this work, we developed a generic computational method to automatically tune the expression of heterologous genes within a microbiome according to given preferences, to allow the functionality of the engineering process to propagate in longer periods of time. This goal was achieved by treating each part of the gene individually and considering long term fitness effects on the environment, providing computational and experimental evidence for this approach.

Abstract

Recent research in the field of bioinformatics and molecular biology has revealed the immense complexity and uniqueness of microbiomes, while also showcasing the impact of the symbiosis between a microbiome and its host or environment. A core property influencing this process is horizontal gene transfer between members of the bacterial community used to maintain genetic variation. The essential effect of this mechanism is the exposure of genetic information to a wide array of members of the community, creating an additional “layer” of information in the microbiome named the “plasmidome”. From an engineering perspective, introduction of genetic information to an environment must be facilitated into chosen species which will be able to carry out the desired effect instead of competing and inhibiting it. Moreover, this process of information transfer imposes concerns for the biosafety of genetic engineering of microbiomes as exposure of genetic information into unwanted hosts can have unprecedented ecological impacts. Current technologies are usually experimentally developed for a specific host/environment, and only deal with the transformation process itself at best, ignoring the impact of horizontal gene transfer and gene-microbiome interactions that occur over larger periods of time in uncontrolled environments. The goal of this research was to design new microbiome-specific versions of engineered genetic information, providing an additional layer of compatibility to existing engineering techniques. The engineering framework is entirely computational and is agnostic to the selected microbiome or gene by reducing the problem into the following set up: microbiome species can be defined as wanted or unwanted hosts of the modification. Then, every element related to gene expression (e.g., promoters, coding regions, etc.) and regulation is individually examined and engineered by novel algorithms to provide the defined expression preferences. Additionally, the synergistic effect of the combination of engineered gene blocks facilitates robustness to random mutations that might occur over time. This method has been validated using both computational and experimental tools, stemming from the research done in the iGEM 2021 competition, by the TAU group.

Nitrogen source: an effective component for the growth and viability of Lactobacillus delbrueckii subsp. bulgaricus

In this study, we developed and optimized a growth media by evaluating various nitrogen sources for the cultivation of Lactobacillus bulgaricus, a probiotic and an important dairy starter culture. We modified the composition of deMan, Rogosa and Sharpe (MRS) culture media and substituted the nitrogen content with alternative nitrogen sources X-Seed KAT, X-Seed Carbo Max and X-Seed Nucleo Max in various blends of 5 g/l and 10 g/l respectively. Results showed that bacterial growth was significantly higher when the nitrogen source blend KCMax (10/10) was used. The optical density (OD610 nm) of the Lactobacillus bulgaricus strains were higher (1.34 and 1.79) in the KCMax (10/10) medium than in the MRS medium (0.89 and 1.42) (P < 0.05). There was no significant difference in the bacterial counts for both the MRS medium and the KCMax (10/10) medium, and all bacterial counts were estimated at 8 log CFU/ml. The buffering capacity of KCMax (10/10) was also tested and supplemented with l-histidine and was significantly different (P < 0.05) than that of the MRS control medium. Calcium supplemented in the KCMax (10/10) also served as a cryoprotectant for the cells during freezing and freeze-drying. Bacterial counts of the recovered calcium-treated freeze-dried cells were statistically significant (P < 0.05). We hypothesized that alternative nitrogen sources such as selected yeast extracts from the X-Seed brand of complex nitrogen sources could efficiently support the viability of Lb. bulgaricus. Our results thus suggested the growth of Lb. bulgaricus was efficiently supported by the X-Seed KAT, X-Seed Nucleo Max and X-Seed Carbo Max nitrogen sources. Consequently, these alternative nitrogen sources could potentially be recommended for dairy starter culture fermentations.

Clinical Potential of Microbial Strains, Used in Fermentation for Probiotic Food, Beverages and in Synbiotic Supplements, as Psychobiotics for Cognitive Treatment through Gut–Brain Signaling

Pure and viable strains of microorganisms identified and characterized as probiotic strains are used in the fermentation process to prepare probiotic food and beverages. These products are sources of nutrition and help in the maintenance of gut microflora. The intake of food products prepared with the use of probiotic microorganisms and containing their metabolites and whole microbial cells can be considered as a natural formulation of synbiotic products with prebiotic substrates and culture. Other than through the intake of fermented food and beverages, probiotic microorganisms can be taken through a supplement, which is a complementary form prepared by combining separate sources of prebiotic substrates and specific probiotic cultures. Whether a fermented solid food or beverage, both the components in the product are in a synergistic relationship and contribute to several health benefits at a lower cost. The aim of this article is to review the relevant literature and present the outcomes of recent studies which have been conducted to explore the clinical potential of probiotic strains and their effect on psychological conditions. Studies have shown the relationship between gut microbiota and the brain, and their interaction through signaling. The studies have concluded that the gut–brain axis can be manipulated with the intake of probiotic foods or synbiotic supplements containing specific probiotic strains accompanied with their complementary prebiotics for the enhanced sustainability of healthy GIT microflora.

New insights into perceptions of technology claims in greek-style yogurt: A view in the COVID-19 pandemic

The Covid-19 pandemic has strongly impacted people's lives and the food industry. In this sense, food products claiming nutritional and health-promoting benefits due to the presence of bioactive peptides and probiotics, such as Greek-style yogurt, have been in demand. The objective of this work was to investigate, through word association, the perception of the consumers regarding the seven concepts related to Greek-style yogurt (traditional, ultra-creamy, zero fat, high content proteins, zero lactose, light and with no added sugars), in the context of social isolation due to Covid-19. In this online survey, 346 participants completed a questionnaire. The participants were divided according to health concerns (increased, not changed, or decreased) and eating habits (improved, not changed, or worsened) during the Covid-19 pandemic. Chi-square and prototypical analysis were used as statistical tests. During the Covid-19 pandemic, based on self-report, around 66% of the participants had their eating habits and their concerns about health changed. The general associations were related to the categories pleasure, health, creamy, pleasant texture, food restriction, and loss of sensory quality. 'Health' and 'pleasure' were negatively associated with the conceptualization of Greek-style yogurt. For the zero-fat, light, and sugar-free Greek-style yogurts, the terms creamy and ultra-creamy are sensory appealing to the consumers. In general, the price and concerns about health are factors that strongly influence the purchase intention of Greek-style yogurts. The yogurts were associated with sensory and non-sensory characteristics, which can be useful for marketing strategies for of different product concepts.

Effect of Chilled Storage on Antioxidant Capacities and Volatile Flavors of Synbiotic Yogurt Made with Probiotic Yeast Saccharomyces boulardii CNCM I-745 in Combination with Inulin

Fermentation of available sugars in milk by yogurt starter culture initially and later by Saccharomyces boulardii (Probiotic yeast) improves the bioavailability of nutrients and produces bioactive substances and volatile compounds that enhance consumer acceptability. The combination of S. boulardii, a unique species of probiotic yeast, and inulin, an exopolysaccharide used as a prebiotic, showed remarkable probiotic and hydrocolloid properties in dairy products. The present study was designed to study the effect of fermentation and storage on antioxidant and volatile capacities of probiotic and synbiotic yogurt by incorporation of S. boulardii and inulin at 1%, 1.5%, and 2% (w/v), compared with the probiotic and control plain yogurt. All samples were stored at 4 °C, and during these four weeks, they were analyzed in terms of their antioxidant and volatile compounds. The synbiotic yogurt samples having inulin and S. boulardii displayed significantly higher DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical activity values and more values of TPC (total phenol contents) than control plain yogurt. A total of 16 volatile compounds were identified in S5-syn2 and S4-syn1.5, while S3-syn1 and S2-P had 14, compared with the control S1-C plain yogurt samples, which had only 6. The number of volatile compounds increased with the increasing concentration of inulin throughout the storage period. Therefore, this novel synbiotic yogurt with higher antioxidant and volatile compounds, even with chilling storage conditions, will be a good choice for consumer acceptability.

Development of rice based probiotic yogurt enriched with some fruit pulps and its quality analysis

Yogurt is one of the popular dairy products produced by the bacterial fermentation of milk. Researches proved that fruit enriched Rice-based yogurt is good alternative for the traditional yogurt. Hence, four different combinations of rice-based yogurt were prepared by adding rice slurry. Rice-based yogurt containing 25% milk and 75% rice slurry scored best in microbial analysis. Count of both Streptococcus salivarius ssp. thermophilus and Lactobacillus delbrueckii ssp. bulgaricus were higher in this combination but organoleptic quality was poor. The one with 75% milk and 25% slurry scored best in organoleptic analysis as it scored high in all the characters under study. Hence the combination with 75% milk and 25% slurry was selected and was enriched with the fruit pulps of Annona, Papaya and Guava. The one with 20% Annona fruit pulp and one with 5% Papaya fruit pulp were selected as the best combinations as they got the highest overall acceptability score and the count of both the bacteria were higher in these combinations, proved that fruit enrichment doesn't affect bacteria in yogurt. Cost analysis proved that collection of fruits from wild will help to reduce the price of the yogurt. Thus, Rice-based Probiotic Yogurt with 75% milk and 25% rice slurry with 20% Annona fruit pulp and one with 5% Papaya fruit pulp were developed as best combinations and can replace normal yogurts currently available in the market with low cost.

Higher Yogurt Consumption Is Associated With Lower Risk of Colorectal Cancer: A Systematic Review and Meta-Analysis of Observational Studies

Background: Yogurt is known to be nutrient-rich and probiotic content, which gather optimism due to their potential role in preventing and managing cancers. The effect of yogurt consumption on colorectal cancer (CRC) is inconsistent.

Objective: This study aims to investigate the association of yogurt consumption with the risk of CRC.

Methods: Three databases, namely, PubMed, Web of Science, and Embase, were searched for all relevant studies from July 2021 on the association of yogurt consumption with CRC risk. We pooled the odds ratios (ORs) and their 95% CIs using a random-effects meta-analysis to assess the association.

Results: Finally, 16 studies met the inclusion criteria and were chosen in the meta-analysis. Yogurt consumption was significant with lower risk of CRC risk in the overall comparison (OR = 0.87, 95% CI: 0.81–0.94), in the cohort studies (OR = 0.91, 95% CI: 0.86–0.97), and case-control studies (OR = 0.75, 95% CI: 0.65–0.85). With regard to subgroup analyses by study region, cancer type, publication year, and sex, yogurt consumption significantly decreased overall CRC, colon cancer, and distal colon cancer risks. In stratified analyses, we observed significantly decreased CRC risk in Europe and Africa and published after 2010 and overall population. Sensitivity analysis indicated the result is stable and there is no publication bias in the meta-analysis.

Conclusions: Overall, this study indicated that yogurt intake was related to a decreased risk of CRC.

Exploitation of Yeasts with Probiotic Traits for Kefir Production: Effectiveness of the Microbial Consortium

Kefir is a fermented milk made by beneficial lactic acid bacteria and yeasts inoculated as grains or free cultures. In this work, five yeast strains with probiotic aptitudes belonging to Candida zeylanoides, Yarrowia lipolytica, Kluyveromyces lactis, and Debaryomyces hansenii species were assessed in a defined consortium, in co-culture with a commercial strain of Lactobacillus casei, in order to evaluate the yeasts’ fermentation performance during kefir production, using different milks. The concentration of each yeast was modulated to obtain a stable consortium that was not negatively affected by the bacteria. Furthermore, all yeasts remained viable for five weeks at 4 °C, reaching about 8.00 Log CFU in 150 mL of kefir, a volume corresponding to a pot of a commercial product. The yeasts consortium showed a suitable fermentation performance in all milks, conferring peculiar and distinctive analytical and aromatic properties to the kefirs, confirmed by a pleasant taste. Overall, the panel test revealed that the cow’s and sheep’s kefir were more appreciated than the others; this evaluation was supported by a distinctive fermentation by-products’ content that positively influences the final aroma, conferring to the kefir exalted taste and complexity. These results allow us to propose the yeasts consortium as a versatile and promising multistarter candidate able to affect industrial kefir with both recognizable organoleptic properties and probiotic aptitudes.

Metagenomics assembled genome scale analysis revealed the microbial diversity and genetic polymorphism of Lactiplantibacillus plantarum in traditional fermented foods of Hainan, China

Exploring the microbiome in fermented foods and their effects on food quality and sustainability is beneficial to provide data support for understanding how they affects human physiology. Here, metagenomic sequencing and metagenomic assembled genomes (MAGs) were applied to appraise the microbial diversity of fermented Yucha (FYC) and fermented vegetables (FVE). The antibiotic resistance genes (ARGs) enrichment and genetic polymorphism of Lactiplantibacillus plantarum in fermented foods of different regions were compared. The results showed that Lactiplantibacillus plantarum was the dominant species in FYC, while Lactiplantibacillus fermentum in FVE occupied the dominant position. From 32 high-quality MAGs, the central differential Lactic acid bacteria were higher in FVE. By comparing the Lactiplantibacillus plantarum MAGs in Hainan and Other regions, we found that the total Single Nucleotide Polymorphisms of Lactiplantibacillus plantarum in Hainan were significantly higher than other areas. Six non-synonymous mutations were included in the primary differential mutation, especially TrkA family potassium uptake protein and MerR family transcriptional regulator, which may be related to the hypersaline environment and highest ARGs enrichment in Hainan. This research provides valuable insight into our understanding of the microbiome of fermented food. Meanwhile, the analysis of Lactiplantibacillus plantarum genetic polymorphism based on MAGs helps us understand this strain's evolutionary history.

Exopolysaccharide Produced by Plant-Derived Lactobacillus plantarum SN35N Exhibits Antiviral Activity

A lactic acid bacterial strain, Lactobacillus plantarum SN35N, which has been isolated from the pear, secretes negatively charged acidic exopolysaccharide (EPS) to outside cells. We have previously found that the SN35N-derived acidic EPS inhibits the catalytic activity of hyaluronidase (EC 3.2.1.35) promoting inflammation. The aim of this study is to find other health benefits of EPS. EPS has been found to exhibit an inhibitory effect against the influenza virus (Alphainfluenzavirus Influenza A virus) and feline calicivirus (Vesivirus Feline calicivirus), which is recognized as a model of norovirus. Although more studies on the structure-function relationship of EPSs are needed, SN35N-derived EPS is a promising lead for developing not only anti-inflammatory agents, but also antiviral substances.

Plant-Derived Lactobacillus paracasei IJH-SONE68 Improves Chronic Allergy Status: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

We have recently demonstrated that the exopolysaccharides (EPSs) produced by a plant-derived lactic acid bacterium, Lactobacillus paracasei IJH-SONE68, prevent and ameliorate allergic reaction on contact in dermatitis model mice. In the present study, we conducted a clinical trial using a capsule containing spray-dried powder from pineapple juice broth fermented with the LAB strain as an experimental diet. The clinical trial was conducted as a double-blind and placebo-controlled randomized comparative study from May 2019 to July 2021. Males and females between the ages of 21 and 70 who experience chronic allergies participated in the study. Sixty subjects were instructed to orally take a capsule containing the IJH-SONE68 powder or placebo, every day for 12 weeks. After the clinical trial was over, the scores based on subjects' self-assessment of allergic status were significantly improved in the intervention group, as compared with the placebo group. Some serum biochemicals associated with inflammation response were also significantly improved by intake of the experimental diet. In conclusion, the IJH-SONE68-derived EPS improves chronic allergy status in humans and is expected to decrease their inconvenience.

Co-Fermentation by Lactobacillus brevis B7 Improves the Antioxidant and Immunomodulatory Activities of Hydroponic Ginseng-Fortified Yogurt

The development of convenient and accessible health-functional foods has become an area of increased interest in recent years. Probiotics, ginseng, and yogurts have been recognized as representative nutraceutical products. To improve the functionality of yogurts, co-fermentation was performed during yogurt preparation. Four kinds of yogurt were prepared using a combination of probiotic Lactobacillus brevis B7 and hydroponic ginseng based on plain yogurt. The fundamental characteristics of yogurts, including pH, titratable acidity, microbial counts, color, and physicochemical properties, were determined. To assess functionality, four different antioxidant assays and real-time PCR analysis using RAW 264.7 cells were performed. Finally, sensory evaluation was conducted to evaluate customer preference. Hydroponic ginseng supplementation influenced pH, solid content, lightness, and yellowness. However, probiotic supplementation did not affect most factors except pH. In functionality analysis, the yogurt co-fermented with probiotics and ginseng showed the highest antioxidant activity and gene expression levels of the immune-related factors TNF-α and iNOS in RAW 264.7 cells. Although ginseng supplementation received poor acceptance because of its color and flavor, these attempts were considered beneficial despite the risk. Overall, co-fermentation within a short yogurt preparation time presented the potential for improvement of functionality. These findings suggest a range of feasibility for the development of attractive nutraceutical products.

Fermented foods and probiotics: An approach to lactose intolerance

The aim of this review was to present various topics related to lactose intolerance with special attention given to the role of fermented foods and probiotics in alleviating gastrointestinal symptoms. Lactose intolerance is a common digestive problem in which the human body is unable to digest lactose, known as milk sugar. Lactose intolerance can either be hereditary or a consequence of intestinal diseases. Recent work has demonstrated that fermented dairy products and probiotics can modify the metabolic activities of colonic microbiota and may alleviate the symptoms of lactose intolerance. We suggest that, lactose free dairy products could be recommended as alternatives for the alleviation of lactose intolerance and for the promotion of human health and wellness.

Dairy-Derived and Egg White Proteins in Enhancing Immune System Against COVID-19

Coronavirus disease (COVID-19) is a global health challenge, caused by the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) triggers a plethora of respiratory disturbances and even multiple organs failure that can be fatal. Nutritional intervention is one of the key components toward to a proper management of COVID-19 patients, especially in those requiring medication, and should thus be considered the first-line treatment. Immuno-modulation and -stimulation are currently being explored in COVID-19 management and are gaining interest by food and pharmaceutical industries. Various dietary combinations, bioactive components, nutrients and fortified foods have been reported to modulate inflammation during disease progression. Dietary combinations of dairy-derived products and eggs are gaining an increasing attention given the huge immunomodulatory and anti-inflammatory properties attributed to some of their chemical constituents. Eggs are complex dietary components containing many essential nutrients and bioactive compounds as well as a high-quality proteins. Similarly, yogurts can replenish beneficial bacteria and contains macronutrients capable of stimulating immunity by enhancing cell immunity, reducing oxidative stress, neutralizing inflammation and regulating the intestinal barriers and gut microbiome. Thus, this review highlights the impact of nutritional intervention on COVID-19 management, focusing on the immunomodulatory and inflammatory effects of immune-enhancing nutrients.

Lactobacillus reuteri BM53-1 Produces a Compound That Inhibits Sticky Glucan Synthesis by Streptococcus mutans

Cariogenic bacteria, such as Streptococcus (S.) mutans and S. sobrinus, produce insoluble and sticky glucans as a biofilm material. The present study demonstrates that a lactic acid bacterium (LAB) named BM53-1 produces a substance that inhibits the sticky glucan synthesis. The BM53-1 strain was isolated from a flower of Actinidia polygama and identified as Lactobacillus reuteri. The substance that inhibits sticky glucan synthesis does not exhibit antibacterial activity against S. mutans. The cariogenic S. mutans produces glucans under the control of three glucosyltransferase (GTF) enzymes, named GtfB, GtfC, and GtfD. Although GtfB and GtfC produce insoluble glucans, GtfD forms soluble glucans. Through quantitative reverse-transcriptional (qRT)-PCR analysis, it was revealed that the BM53-1-derived glucan-production inhibitor (GI) enhances the transcriptions of gtfB and gtfC genes 2- to 7-fold at the early stage of cultivation. However, that of gtfD was not enhanced in the presence of the GI, indicating that the glucan stickiness produced by S. mutans was significantly weaker in the presence of the GI. Our result demonstrates that Lb. reuteri BM53-1 is useful to prevent dental caries.

Consumption of OLL1073R-1 yogurt improves psychological quality of life in women healthcare workers: secondary analysis of a randomized controlled trial

Background

We conducted a randomized controlled trial to investigate the effects of consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 in women healthcare workers. In a previous study we used these data to investigate hypothesized preventive effects against flu, however any effects on improving mental quality of life were not analyzed at that time. In the present study, we focus on that aspect.

Methods

The participants (961 women; mainly nurses, aged 20–71 years) were randomly allocated to either the yogurt group (n = 479) or the control group (n = 482). Participants in the yogurt group drank 112 mL of OLL1073R-1 yogurt for 16 weeks, while those in the control group did not consume any yogurt. All participants were prohibited from consuming other yogurt or fermented dairy products during the study period. The participants answered the Pittsburgh Sleep Quality Index (PSQI), Short Form-8 Health Survey (SF-8), and Gastrointestinal Symptom Rating Scale (GSRS) questionnaires at baseline and after 16 weeks.

Results

The PSQI score showed significant improvement after the intake of yogurt (p < 0.01). SF-8 results showed significant intervention effects in the General Health and Vitality scores (p = 0.02 and p = 0.01, respectively). In other subscales of SF-8, we did not observe significant effects of the yogurt. In the GSRS, daily intake of yogurt exerted a preventive effect on constipation (p = 0.03).

Conclusions

Consumption of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 enhances subjective psychological quality of life by improving quality of sleep and gastrointestinal condition among women healthcare workers.

Gut microbiota mediated molecular events and therapy in liver diseases

Gut microbiota is a community of microorganisms that reside in the gastrointestinal tract. An increasing number of studies has demonstrated that the gut-liver axis plays a critical role in liver homeostasis. Dysbiosis of gut microbiota can cause liver diseases, including nonalcoholic fatty liver disease and alcoholic liver disease. Preclinical and clinical investigations have substantiated that the metabolites and other molecules derived from gut microbiota and diet interaction function as mediators to cause liver fibrosis, cirrhosis, and final cancer. This effect has been demonstrated to be associated with dysregulation of intrahepatic immunity and liver metabolism. Targeting these findings have led to the development of novel preventive and therapeutic strategies. Here, we review the cellular and molecular mechanisms underlying gut microbiota-mediated impact on liver disease. We also summarize the advancement of gut microbiota-based therapeutic strategies in the control of liver diseases.

Lactic Acid Bacteria: Food Safety and Human Health Applications

Research on lactic acid bacteria has confirmed how specific strains possess probiotic properties and impart unique sensory characteristics to food products. The use of probiotic lactic acid bacteria (LAB) in many food products, thus confers various health benefits to humans when they are frequently consumed in adequate amounts. The advent of functional food or the concept of nutraceuticals objectively places more emphasis on seeking alternatives to limit the use of medications thus promoting the regular consumption of fermented foods. Probiotic use has thus been recommended to fulfill the role of nutraceuticals, as no side effects on human health have been reported. Probiotics and lactic acid bacteria can boost and strengthen the human immune system, thereby increasing its resistance against numerous disease conditions. Consumer safety and confidence in dairy and fermented food products and the desire of the food industry to meet the sensory and health needs of consumers, has thus increased the demand for probiotic starter cultures with exceptional performance coupled with health benefiting properties. The potential of probiotic cultures and lactic acid bacteria in many industrial applications including fermented food products generally affects product characteristics and also serves as health-promoting foods for humans. The alleviation of lactose intolerance in many populations globally has been one of the widely accepted health claims attributed to probiotics and lactic acid bacteria, although many diseases have been treated with probiotic lactic acid bacteria and have been proven with scientific and clinical studies. The aim of our review was to present information related to lactic acid bacteria, the new classification and perspectives on industrial applications with a special emphasis on food safety and human health.

Postprandial Effect of Yogurt Enriched with Anthocyanins from Riceberry Rice on Glycemic Response and Antioxidant Capacity in Healthy Adults

The pigment of riceberry rice has been reported to contain anthocyanins which act as a free radical scavenger and inhibitor of carbohydrate digestive enzymes. Since the probiotic yogurt incorporated with the pigment of riceberry rice extract was previously developed, the present study was aimed to investigate the acute effect of riceberry rice yogurt consumption on postprandial glycemic response, antioxidant capacity, and subjective ratings in healthy adults. In a cross-over design, 19 healthy participants were randomized to consume 350 g of yogurt supplemented with 0.25% (w/w) riceberry rice extract or the control yogurt. Postprandial plasma glucose, antioxidant status, and subjective ratings were measured at fasting and intervals (0–3 h) after ingestion of yogurt. The primary outcome was glycemic response; the secondary outcomes were plasma antioxidant capacity. In comparison to the yogurt control, riceberry rice yogurt reduced plasma glucose concentration after 30 min of consumption. The incremental area under the curve (iAUC) was significantly lower after riceberry rice yogurt load than after the control yogurt load. The consumption of riceberry yogurt caused an acute increase in plasma ferric reducing ability of plasma (FRAP), Trolox equivalent antioxidant capacity (TEAC), and oxygen radical absorbance capacity (ORAC) from the baseline values after 60 min of 0.25 ± 0.06 mM FeSO₄, 253.7 ± 35.5 mM Trolox equivalents, and 166.8 ± 28.9 mM Trolox equivalents, respectively. Furthermore, the iAUCs for FRAP, TEAC, ORAC, and protein thiol were higher in riceberry yogurt consumption compared with the control yogurt (1.6-, 1.6-, 2.9-, and 1.9-fold, respectively). A decrease in iAUC for plasma malondialdehyde (MDA) concentration was also observed in the riceberry yogurt group. However, consumption of riceberry rice yogurt and control yogurt showed similar subjective rating scores of hunger, desire to eat, fullness, and satiety. In conclusion, acute consumption of riceberry rice yogurt suppressed postprandial glucose level and improved plasma antioxidant capacity in healthy volunteers.

Traditional plain yogurt: a therapeutic food for metabolic syndrome?

Dairy products have an important role in a healthy diet due to their high-quality protein and rich micronutrients. Yogurt, a fermented milk product, has a similar composition to milk but is a more concentrated product in terms of group B vitamins, minerals, and proteins. It is known that bioactive metabolites and live enzymes that occur by fermentation and digestion, affect the health positively by improving gut microbiota. In recent years, the prevalence of metabolic syndrome, which threatens public health, is increasing rapidly. As with other noninfectious diseases, the diet has an important effect on the prevention and treatment of metabolic syndrome. It has been demonstrated that yogurt has a high-quality amino acid pattern, reduces energy intake by stimulating satiety, and regulates blood glucose level. In addition to the rich protein variety, yogurt also contains peptides that positively affect blood pressure. Unlike milk, increased acidity during the fermentation of yogurt positively affects calcium absorption. Calcium plays an important role in the control of blood glucose and energy metabolism through insulin-dependent and non-insulin-dependent routes. In addition to reducing inflammation, calcium has a positive effect on the regulation of the blood lipid profile by increasing fecal fat excretion. There are many lipid and lipoid nutrients such as saturated fatty acids, phospholipids, sphingolipids, and conjugated linoleic acid that may affect the blood lipid profile in yogurt positively or negatively. There are seen very few randomized controlled studies that are focused on the relationship between yogurt and metabolic syndrome, and these are based on contradictory results. In this review, based on the clinical studies conducted to date, and the nutrient content of yogurt, possible mechanisms of these contradictory results are investigated.

Yogurt consumption and colorectal polyps

Diet modifies the risk of colorectal cancer (CRC), and inconclusive evidence suggests that yogurt may protect against CRC. We analysed the data collected from two separate colonoscopy-based case-control studies. The Tennessee Colorectal Polyp Study (TCPS) and Johns Hopkins Biofilm Study included 5446 and 1061 participants, respectively, diagnosed with hyperplastic polyp (HP), sessile serrated polyp, adenomatous polyp (AP) or without any polyps. Multinomial logistic regression models were used to derive OR and 95 % CI to evaluate comparisons between cases and polyp-free controls and case-case comparisons between different polyp types. We evaluated the association between frequency of yogurt intake and probiotic use with the diagnosis of colorectal polyps. In the TCPS, daily yogurt intake v. no/rare intake was associated with decreased odds of HP (OR 0·54; 95 % CI 0·31, 0·95) and weekly yogurt intake was associated with decreased odds of AP among women (OR 0·73; 95 % CI 0·55, 0·98). In the Biofilm Study, both weekly yogurt intake and probiotic use were associated with a non-significant reduction in odds of overall AP (OR 0·75; 95 % CI 0·54, 1·04) and (OR 0·72; 95 % CI 0·49, 1·06) in comparison with no use, respectively. In summary, yogurt intake may be associated with decreased odds of HP and AP and probiotic use may be associated with decreased odds of AP. Further prospective studies are needed to verify these associations.