Purpose A multifunctional diet (MFD) targeting subclinical inflammation was developed as a tool to decrease risk factors for cardiometabolic disease in healthy “at-risk” individuals (BMI 25–33 kg/m²). MFD contains several components that are degraded in the colon by the microbiota, such as dietary fibers from rye, barley, oats and berries. It also contains soy beans, oily fish and plant stanols. In previous studies, we have observed improved cardiometabolic markers in healthy at-risk individuals after 4–8 week intake of MFD. However, whether these improvements can be associated with changes in the gut microbiota composition has not been investigated. In the present study, we analyzed the gut microbiota before and after an 8-week dietary intervention with MFD. Methods Cardiometabolic at-risk individuals (n = 47), between 51 and 72 years old and with a BMI of 25–33 kg/m², were given either the MFD or a control diet lacking the functional (“active”) components for 8 weeks in a parallel, randomized design. Next-generation sequencing of bacterial 16S rRNA genes was used to analyze the gut microbiota composition. Results The 8-week intervention with MFD did not significantly alter the gut microbiota composition at phylum or genus taxonomic levels, while LEfSE analysis identified increased abundance of Prevotella copri in the MFD group as compared to the control group. Treponema correlated positively with blood pressure. In contrast, Faecalibacterium showed a negative association with blood pressure, while Bilophila appeared to associate with a negative blood lipid profile. Conclusions Taken together, results from the present study may be used in the further development of effective dietary concepts capable of reducing cardiometabolic risk markers in humans through a targeted modulation of the gut microbial community. Trial registration number Clinical Trials.gov NCT02148653.

Lingonberries (LB) have been shown to have beneficial metabolic effects, which is associated with an altered gut microbiota. This study investigated whether the LB-induced improvements were associated with altered gut- and neuroinflammatory markers, as well as cognitive performance in ApoE−/− mice fed high-fat (HF) diets. Whole LB, as well as two separated fractions of LB were investigated. Eight-week-old male ApoE−/− mice were fed HF diets (38% kcal) containing whole LB (wLB), or the insoluble (insLB) and soluble fractions (solLB) of LB for 8 weeks. Inclusion of wLB and insLB fraction reduced weight gain, reduced fat deposition and improved glucose response. Both wLB and insLB fraction also changed the caecal microbiota composition and reduced intestinal S100B protein levels. The solLB fraction mainly induced weight loss in the mice. There were no significant changes in spatial memory, but significant increases in synaptic density in the hippocampus were observed in the brain of mice-fed wLB and insLB. Thus, this study shows that all lingonberry fractions counteracted negative effects of HF feedings on metabolic parameters. Also, wLB and insLB fraction showed to potentially improve brain function in the mice.

High-fat diet has been known to have adverse effects on metabolic markers, as well as the gut microbiota. However, the effect of heat processing of high-fat diet, which leads to formations of advanced glycation end products (AGEs) has not been clearly distinguished from the effect of unheated fat. This study compared the effect of high-fat diet with heat-treated high-fat diet on adiposity, atherosclerosis and gut microbiota composition in the caecum of apoe −/− mice. Male apoe −/− mice were fed either low-fat (LF) control diet, high-fat (40 E% saturated fat, HF) control diet, or heat-treated high-fat (200 °C for 10 min, HT) diet, for 8 weeks. The plasma samples were used in the analysis of Nε-carboxy-methyl-lysine (CML) and Nε-carboxy-ethyl-lysine (CEL). The heart samples were analysed for atherosclerotic plaques, and the DNA from caecum was extracted and analysed for microbiota composition using 16S rRNA gene sequencing on a Miseq instrument. Additionally, the functions of microbial communities were also predicted based on the bacterial 16S rRNA gene sequence using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt). Here we found that HT modifies gut microbiota composition and host adiposity. Prediction of bacterial gene functions based on 16S rRNA gene sequence revealed that HF increased bacterial genera enriched in lipid metabolism genes, while HT did not. Plasma CML and CEL increased 1.7 and 2.5 times, respectively, in mice fed HT as compared to mice fed HF. Despite lower adiposity, mice fed HT maintained atherosclerosis and displayed enlarged spleens. The results suggested that heat processing of high-fat diet modifies the substrates reaching the lower gut of apoe −/− mice, resulting in different effects on gut microbiota composition. AGEs seem to maintain the effect on atherosclerosis, despite lower adiposity, and causing enlarged spleens, which possibly reflect elevated levels of inflammation in the body.

Background: Precocious maturation of the gastrointestinal barrier (GIB) in newborn mammals can be induced by dietary provocation, but how this affects the gut microbiota and the gut‐brain axis remains unknown. The objective of this study was to investigate effects of induced GIB maturation on gut microbiota composition and blood‐brain barrier (BBB) permeability.Methods: Suckling rats were studied at 72 h after gavage with phytohemagglutinin (PHA) or microbial protease (PT) to induce maturation of GIB. For comparison, untreated suckling and weaned rats were included (n = 10). Human serum albumin (HSA) was administered orally and analyzed in blood to assess permeability of the GIB, while intraperitoneally injected bovine serum albumin (BSA) was measured in the brain tissue for BBB permeability. The cecal microbial composition, plasma lipopolysaccharide‐binding protein (LBP) levels and short‐chain fatty acids in serum and brain were analyzed.Key Results: Cessation of HSA passage to blood after PHA or PT treatment was similar to that seen in weaned rats. Interestingly, concomitant increases in cecal Bacteroidetes and plasma LBP levels were observed after both PHA and PT treatments. The BBB passage of BSA was surprisingly elevated after weaning, coinciding with lower plasma LBP levels and specific microbial taxa and increased acetate uptake into the brain.Conclusions & Inferences: This study provides evidence that the gut microbiota alteration following induced precocious GIB maturation may induce low‐grade systemic inflammation and alter SCFAs utilization in the brain which may also play a potential role in GIB‐BBB dysfunction disorders in neonates.

High-fat diets are associated with neuronal and memory dysfunction. Berries may be useful in improving age-related memory deficits in humans, as well as in mice receiving high-fat diets. Emerging research has also demonstrated that brain health and cognitive function may be related to the dynamic changes in the gut microbiota. In this study, the impact of Nordic berries on the brain and the gut microbiota was investigated in middle-aged C57BL/6J mice. The mice were fed high-fat diets (60%E fat) supplemented with freeze-dried powder (6% dwb) of bilberry, lingonberry, cloudberry, blueberry, blackcurrant, and sea buckthorn for 4 months. The results suggest that supplementation with bilberry, blackcurrant, blueberry, lingonberry, and (to some extent) cloudberry has beneficial effects on spatial cognition, as seen by the enhanced performance following the T-maze alternation test, as well as a greater proportion of DCX-expressing cells with prolongation in hippocampus. Furthermore, the proportion of the mucosa-associated symbiotic bacteria Akkermansia muciniphila increased by 4–14 times in the cecal microbiota of mice fed diets supplemented with lingonberry, bilberry, sea buckthorn, and blueberry. These findings demonstrate the potential of Nordic berries to preserve memory and cognitive function, and to induce alterations of the gut microbiota composition.