Lacticaseibacillus rhamnosus GG DSM 33156 effects on pathogen defence in the upper respiratory tract: a randomised, double-blind, placebo-controlled paediatric trial

Acute upper respiratory tract infections (URTIs) are caused by numerous viruses and bacteria. URTIs can be a cause of morbidity and are among the most common reasons for visiting healthcare practitioners and prescribing antibiotics to children in addition to causing absenteeism from school and work. Oral intake of Lacticaseibacillus rhamnosus GG DSM 33156 has shown beneficial health effects in several clinical trials, primarily relating to immune function and gastrointestinal health in children and adults. It has also been suggested that oral intake of L. rhamnosus GG DSM 33156 can reduce the incidence rate and alleviate symptoms of URTIs in children. We here report the results of a randomised, double-blind, placebo-controlled trial of 619 children aged 2-6 years conducted at a single centre in Scotland. The children, who were in day care or primary school, were followed over a 16-week intervention period with 309 randomised in the active group and 310 in the placebo group. The parents or guardians reported a daily healthcare status and any presumed episodes of URTI, which were subsequently confirmed by a general practitioner. The investigational product was well tolerated in the trial. Although a general trend towards a beneficial effect was observed, this trial did not demonstrate that L. rhamnosus GG DSM 33156 significantly reduced the incidence of URTIs, diagnosed by a general practitioner according to prespecified criteria (primary endpoint). Moreover, none of the secondary efficacy endpoints were met. Applying a Ward's hierarchical clustering, two separate clusters, focussing on four quality of life-related endpoints, were identified. Cluster 1 was associated with more severe URTI characteristics than cluster 2. Cluster 2 was significantly enriched with children who consumed the product, indicating that the symptoms children experience during an URTI are alleviated by the intake of L. rhamnosus GG DSM 33156. The study is registered at ClinicalTrials.gov ID: NCT03636191.

Interactions between Carrageenans and Milk Proteins: A Microstructural and Rheological Study

Gels were produced using kappa-, iota-, or hybrid-carrageenan at a low (0.2-0.25%) and a high (0.7-1.0%) dosage in skim milk. The microstructure of carrageenan and protein was observed by confocal laser scanning microscopy using direct immunostaining. Additionally, rheology was used to characterize the gels. The low kappa- and iota-carrageenan dosages resulted in gels with a fine stranded carrageenan-protein microstructure and emulsion-like inclusions, while the high dosages resulted in strongly flocculated microstructures. Hybrid-carrageenan exhibited flocculation at both dosages. When using iota- and hybrid-carrageenan at a high dosage and kappa-carrageenan at both dosages, the gel characteristics were dominated by carrageenan-carrageenan interactions. On the other hand, the gel with a low dosage of iota-carrageenan in milk was barely fusible, indicating the presence of a true coupled network. We suggest that kappa-, iota-, and hybrid-carrageenan all interact with casein micelles but that the impact of this interaction on the total gel properties varied.