Kefir is fermented milk produced from grains that comprise a specific and complex mixture of bacteria and yeasts that live in a symbiotic association. The nutritional composition of kefir varies according to the milk composition, the microbiological composition of the grains used, the time/temperature of fermentation and storage conditions. Kefir originates from the Caucasus and Tibet. Recently, kefir has raised interest in the scientific community due to its numerous beneficial effects on health. Currently, several scientific studies have supported the health benefits of kefir, as reported historically as a probiotic drink with great potential in health promotion, as well as being a safe and inexpensive food, easily produced at home. Regular consumption of kefir has been associated with improved digestion and tolerance to lactose, antibacterial effect, hypocholesterolaemic effect, control of plasma glucose, anti-hypertensive effect, anti-inflammatory effect, antioxidant activity, anti-carcinogenic activity, anti-allergenic activity and healing effects. A large proportion of the studies that support these findings were conducted in vitro or in animal models. However, there is a need for systematic clinical trials to better understand the effects of regular use of kefir as part of a diet, and for their effect on preventing diseases. Thus, the present review focuses on the nutritional and microbiological composition of kefir and presents relevant findings associated with the beneficial effects of kefir on human and animal health.

Dogs and cats have been cohabiting with us for thousands of years. They are the major human companions. Today, dogs and cats live in urban areas. Cats and most dogs are on high carbohydrate diets and face similar life-style challenges as the human beings. The health and well-being of companion animals, just as their owners, depends on the gut microbes. Providing a proper care and nutritionally balanced diet to companion animals is recognised as a part of our responsibility to maintain the health and well being of our pet. However, as microbiota differences may facilitate exposure to pathogens and harmful environmental influences, it is prudent to search for novel tools to protect dogs and cats and at the same time the human owners from pathogens. Specific probiotic strains and/or their defined combinations may be useful in the canine and feline nutrition, therapy, and care. Probiotic supplementations have been successful in the prevention and treatment of acute gastroenteritis, treatment of IBD, and prevention of allergy in companion animals. New challenges for probiotic applications include maintenance of obesity and overweight, urogenital tract infections, Helicobacter gastritis and parasitic infections. The probiotics of human origin appear to be among the new promising tools for the maintenance of pets' health. However, the host-derived microorganisms might be the most appropriate probiotic source. Therefore, more controlled trials are needed to characterise new and safe probiotic preparations with an impact on general health and well being as well as health maintenance in dogs and cats.

Dietary fat strongly affects human health by modulating gut microbiota composition and low-grade systemic inflammation. High-fat diets have been implicated in reduced gut microbiota richness, increased Firmicutes to Bacteroidetes ratio, and several changes at family, genus and species levels. Saturated (SFA), monounsaturated (MUFA), polyunsaturated (PUFA) and conjugated linolenic fatty acids share important pathways of immune system activation/inhibition with gut microbes, modulating obesogenic and proinflammatory profiles. Mechanisms that link dietary fat, gut microbiota and obesity are mediated by increased intestinal permeability, systemic endotoxemia, and the activity of the endocannabinoid system. Although the probiotic therapy could be a complementary strategy to improve gut microbiota composition, it did not show permanent effects to treat fat-induced dysbiosis. Based upon evidence to date, we believe that high-fat diets and SFA consumption should be avoided, and MUFA and omega-3 PUFA intake should be encouraged in order to regulate gut microbiota and inflammation, promoting body weight/fat control.

The gut microbiota of 6-month-old infants in a low-income country differs significantly from that in a high-income country. This may have an effect on both the energy harvest from the diet typifying malnutrition and diarrheal diseases in low-income countries and Western lifestyle diseases in high-income countries.

The aim of this study was to investigate in vitro the protective effect of commercial probiotic strains (Bifidobacterium lactis Bb12 and Lactobacillus rhamnosus LGG) alone and in combination on the adhesion of pathogenic strains as Salmonella, Clostridium, and Escherichia coli to pig intestinal mucus obtained from different intestinal regions. In combination, probiotic strains enhanced each other's adhesion, mainly in large intestinal mucus. Treatment of intestinal mucus with Bb12 and LGG, alone or in combination, significantly reduced (P < 0.05) the adhesion of the tested pathogens. The ability to inhibit pathogen adhesion appears to depend on the specific probiotics and pathogens and on the mucosal site. B. lactis Bb12 and L. rhamnosus LGG in combination revealed a better ability to inhibit adhesion of all pathogens tested to pig intestinal mucus than probiotic strains. Probiotic combinations could be useful for counteracting disease-associated aberrations in intestinal microbiota. Specific protective probiotics could be selected for particular pig pathogens. Probiotic strains from human origin and intended for human use also adhere to pig intestinal mucus and are able to displace and inhibit pathogens.

The aim here was to elucidate the mother-infant association in the gut colonization of 1-6 month-old infants and to establish whether probiotics can influence this process. Fecal samples from 80 mother-infant pairs were analyzed at 1 month (mothers and infants) and 6 months (infants) by real-time polymerase chain reaction to assess bacterial numbers. This double-blind placebo-controlled trial involved 2 different probiotic combinations (1. Lactobacillus rhamnosus + Bifidobacterium longum and 2. Lactobacillus paracasei + Bifidobacterium longum) given to the mothers 2 months prior to and 2 months after delivery. Bifidobacterium bifidum colonization in the mothers significantly increased the infants' probability of being colonized by B. bifidum and their bifidobacterial diversity indexes (DI) and the mother-infant similarity indexes (SI) both at 1 and 6 months of age. The counts of Bifidobacterium genus (at 1 month) and Bifidobacterium longum (at 6 months) correlated between mothers and infants. At 6 months, a significant effect of the probiotic intervention was found in the mother-infant association of fecal bifidobacterial counts but not in the colonization frequencies, DI or SI. In conclusion, a clear association between mother and infant was found in gut colonization by bifidobacteria. Maternal colonization by B. bifidum had the most consistent effects on the infant's bifidobacterial microbiota. Maternal probiotic treatment had little effect on this mother-infant association.

SCFA provide energy to the host and influence lipid and glucose metabolism, suggesting that they may have an impact on the occurrence of metabolic risk factors. The aim of the present study was to determine the concentration of SCFA in faeces of lean and obese individuals and to analyse whether associations between faecal SCFA and metabolic syndrome parameters are present. Lean (n 20) and obese (n 20) women of similar age (28·5 (SD 7·6) v. 30·7 (SD 6·5) years, P¼ 0·33) participated in the study. Anthropometric measurements, body composition, blood pressure and biochemical parameters were assessed. SCFA were extracted from faeces and quantified by GC. Blood pressure and blood glucose, although within the normal limits, were higher in the obese group compared to lean subjects (P,0·05). Lower HDL concentration and higher insulin and homeostasis model assessment (HOMA) index were observed in the obese than in the lean group (P, 0·05). The median values of SCFA (% w/w) from the lean and obese groups were butyric (0·021 v. 0·044, P¼ 0·024), propionic (0·021 v. 0·051, P¼ 0·007) and acetic (0·03 v. 0·061, P¼ 0·01). SCFA correlated positively with metabolic syndrome risk factors such as adiposity, waist circumference and HOMA index (P,0·05), and inversely with HDL (P,0·05). Our results suggest that the higher faecal concentration of SCFA is associated with metabolic risk factors and thus may influence metabolic homeostasis.

SUMMARY Celiac disease (CD) is a common chronic autoimmune enteropathy caused by gluten intake. To date, the only therapy for CD is the complete exclusion of dietary sources of grains and any food containing gluten. It has been hypothesized that the intestinal microbiota is somehow involved in CD. For this reason, probiotics are appearing as an interesting adjuvant in the dietetic management of CD. This review aims to discuss the characteristics of the microbiota in CD subjects and the use of probiotics as a novel therapy for CD. Comparisons between children with CD and controls show that their microbiota profiles differ; the former have fewer lactobacilli and bifidobacteria. Specific probiotics have been found to digest or alter gluten polypeptides. It has also been demonstrated that some bacterial species belonging to the genera Lactobacillus and Bifidobacterium exert protective properties on epithelial cells from damage caused by gliadin.