The Role of Oligosaccharides in Host-Microbial Interactions for Human Health.

Milk oligosaccharides have many associated bioactivities which can contribute to human health and offer protective properties to the host. Such bioactivities include anti-infective properties whereby oligosaccharides interact with bacterial cells and prevent adhesion to the host and subsequent colonization. Milk oligosaccharides have also been shown to alter the glycosylation of intestinal cells, leading to a reduction in pathogenic colonization. In addition, these sugars promote adhesion of commensal bacterial strains to host cells as well as possessing the ability to alter mucin expression in intestinal cells and improve barrier function. The ability of milk oligosaccharides to alter the transcriptome of both commensal bacterial strains and intestinal epithelial cells has also been revealed, indicating the potential of many cell types to detect the presence of milk oligosaccharides and respond accordingly at the genetic level. Interestingly, domestic animal milk may provide a bioactive source of oligosaccharides for formula supplementation with the aim of emulating the gold standard that is human milk. Overall, this review highlights the ability of milk oligosaccharides to promote health in a variety of ways, for example, through direct bacterial interactions, immunomodulatory activities, promotion of gut barrier function, and induction of protective transcriptional responses.

Suppression of Food Allergic Symptoms by Raw Cow's Milk in Mice is Retained after Skimming but Abolished after Heating the Milk-A Promising Contribution of Alkaline Phosphatase.

Raw cow's milk was previously shown to suppress allergic symptoms in a murine model for food allergy. In the present study, we investigated the contribution of fat content and heat-sensitive milk components to this allergy-protective effect. In addition, we determined the potency of alkaline phosphatase (ALP), a heat-sensitive raw milk component, to affect the allergic response. C3H/HeOuJ mice were treated with raw milk, pasteurized milk, skimmed raw milk, pasteurized milk spiked with ALP, or phosphate-buffered saline for eight days prior to sensitization and challenge with ovalbumin (OVA). Effects of these milk types on the allergic response were subsequently assessed. Similar to raw milk, skimmed raw milk suppressed food allergic symptoms, demonstrated by a reduced acute allergic skin response and low levels of OVA-specific IgE and Th2-related cytokines. This protective effect was accompanied by an induction of CD103+CD11b+ dendritic cells and TGF-ß-producing regulatory T cells in the mesenteric lymph nodes. Pasteurized milk was not protective but adding ALP restored the allergy-protective effect. Not the fat content, but the heat-sensitive components are responsible for the allergy-protective effects of raw cow's milk. Adding ALP to heat-treated milk might be an interesting alternative to raw cow's milk consumption, as spiking pasteurized milk with ALP restored the protective effects.

Glycomacropeptide Reduces Intestinal Epithelial Cell Barrier Dysfunction and Adhesion of Entero-Hemorrhagic and Entero-Pathogenic Escherichia coli in Vitro.

In recent years, the potential of glycosylated food components to positively influence health has received considerable attention. Milk is a rich source of biologically active glycoconjugates which are associated with antimicrobial, immunomodulatory, anti-adhesion, anti-inflammatory and prebiotic properties. Glycomacropeptide (GMP) is the C-terminal portion of kappa-casein that is released from whey during cheese-making by the action of chymosin. Many of the biological properties associated with GMP, such as anti-adhesion, have been linked with the carbohydrate portion of the protein. In this study, we investigated the ability of GMP to inhibit the adhesion of a variety of pathogenic Escherichia coli strains to HT-29 and Caco-2 intestinal cell lines, given the importance of E. coli in causing bacterial gastroenteritis. GMP significantly reduced pathogen adhesion, albeit with a high degree of species specificity toward enteropathogenic E. coli (EPEC) strains O125:H32 and O111:H2 and enterohemorrhagic E. coli (EHEC) strain 12900 O157:H7. The anti-adhesive effect resulted from the interaction of GMP with the E. coli cells and was also dependent on GMP concentration. Pre-incubation of intestinal Caco-2 cells with GMP reduced pathogen translocation as represented by a decrease in transepithelial electrical resistance (TEER). Thus, GMP is an effective in-vitro inhibitor of adhesion and epithelial injury caused by E. coli and may have potential as a biofunctional ingredient in foods to improve gastrointestinal health.

Bioactive peptides from muscle sources: meat and fish.

Bioactive peptides have been identified in a range of foods, including plant, milk and muscle, e.g., beef, chicken, pork and fish muscle proteins. Bioactive peptides from food proteins offer major potential for incorporation into functional foods and nutraceuticals. The aim of this paper is to present an outline of the bioactive peptides identified in the muscle protein of meat to date, with a focus on muscle protein from domestic animals and fish. The majority of research on bioactives from meat sources has focused on angiotensin-1-converting enzyme (ACE) inhibitory and antioxidant peptides.