News & Publications

• The gut microbiome alters the brain's response to tempting foods, affecting dietary choices. www.sciencedaily.com
  Brain Obesity Microbiome Prebiotics

  The brain’s reward centers react more strongly to the sight of tempting food than to less tempting options, driving food choices. Evidence suggests the gut microbiome influences these neural activity patterns, ultimately modulating body weight and metabolic health. A recent study found that inulin, a prebiotic derived from chicory root, alters the gut microbiome, reducing the intensity of the brain’s reward system activation.

  Researchers gave 59 overweight young to middle-aged adults 30 grams of inulin or a placebo every day for two weeks. Then, the participants underwent functional MRI scans while viewing images of various foods and rating the foods' desirability. Finally, they ate the most desired food and underwent more MRIs. After a two-week break, they switched to the alternate treatment. The researchers collected blood and fecal samples from the participants before and after the two interventions.

  They found that the participants' reward-related brain activation in response to high-calorie food stimuli decreased after consuming the prebiotic inulin. A shift in the gut microbial composition accompanied these changes.

  These findings suggest that prebiotics influence dietary choices via alterations in the gut microbiome. They also highlight the complex interplay between the gut, brain, and the body’s microbial partners. Learn more about the gut microbiome in this episode featuring Dr. Eran Elinav.

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• Probiotic Bifidobacterium strains and galactooligosaccharides improve intestinal barrier function in obese adults microbiomejournal.biomedcentral.com
  Gut Obesity Probiotics Prebiotics Endotoxemia Lipopolysaccharide

  Full Title: Probiotic Bifidobacterium strains and galactooligosaccharides improve intestinal barrier function in obese adults but show no synergism when used together as synbiotics

  Background: One way to improve both the ecological performance and functionality of probiotic bacteria is by combining them with a prebiotic in the form of a synbiotic. However, the degree to which such synbiotic formulations improve probiotic strain functionality in humans has not been tested systematically. Our goal was to use a randomized, double-blind, placebo-controlled, parallel-arm clinical trial in obese humans to compare the ecological and physiological impact of the prebiotic galactooligosaccharides (GOS) and the probiotic strains Bifidobacterium adolescentis IVS-1 (autochthonous and selected via in vivo selection) and Bifidobacterium lactis BB-12 (commercial probiotic allochthonous to the human gut) when used on their own or as synbiotic combinations. After 3 weeks of consumption, strain-specific quantitative real-time PCR and 16S rRNA gene sequencing were performed on fecal samples to assess changes in the microbiota. Intestinal permeability was determined by measuring sugar recovery in urine by GC after consumption of a sugar mixture. Serum-based endotoxin exposure was also assessed.

  Results: IVS-1 reached significantly higher cell numbers in fecal samples than BB-12 (P < 0.01) and, remarkably, its administration induced an increase in total bifidobacteria that was comparable to that of GOS. Although GOS showed a clear bifidogenic effect on the resident gut microbiota, both probiotic strains showed only a non-significant trend of higher fecal cell numbers when administered with GOS. Post-aspirin sucralose:lactulose ratios were reduced in groups IVS-1 (P = 0.050), IVS-1 + GOS (P = 0.022), and GOS (P = 0.010), while sucralose excretion was reduced with BB-12 (P = 0.002) and GOS (P = 0.020), indicating improvements in colonic permeability but no synergistic effects. No changes in markers of endotoxemia were observed.

  Conclusion: This study demonstrated that “autochthony” of the probiotic strain has a larger effect on ecological performance than the provision of a prebiotic substrate, likely due to competitive interactions with members of the resident microbiota. Although the synbiotic combinations tested in this study did not demonstrate functional synergism, our findings clearly showed that the pro- and prebiotic components by themselves improved markers of colonic permeability, providing a rational for their use in pathologies with an underlying leakiness of the gut.

  Keywords: Synbiotic, Probiotic, Prebiotic, Obesity, Gut barrier function, Autochthonous, Allochthonous, Galactooligosaccharide, Bifidobacteria, Bifidobacterium

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• 30% of infants gut bacteria may come from the mother’s breast milk and another 10% has been traced to the skin around the mother’s nipple. www.the-scientist.com
  Gut Microbiome Probiotics Pregnancy Prebiotics

  30% of infants gut bacteria may come from the mother’s breast milk and another 10% has been traced to the skin around the mother’s nipple. There is a specific type of prebiotic found exclusively in breastmilk called human milk oligosaccharides that have been shown to set up the early infant microbiome. The bacteria around the skin of the nipple also appears to be important for seeding the infant microbiome. While this study did not examine health consequences of breastfeeding, other studies have found that it is important for immune system development and may protect against obesity.

  To learn more about the role of breastfeeding in setting up the infant microbiome and more generally about how to have a healthy microbiome during adulthood listen to (or watch) my podcast (video/audio) with microbiome experts Drs. Justin and Erica Sonnenburg. YouTube: https://youtu.be/gOZcbNw7sng iTunes: https://itunes.apple.com/us/podcast/sonnenburgs-on-how-gut-microbiota-interacts-our-bodies/id818198322?i=1000351247766&mt=2

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