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Probiotic Bifidobacterium strains and galactooligosaccharides improve intestinal barrier function in obese adults but show no synergism when used together as synbiotics.
Krumbeck, JA, Rasmussen, HE, Hutkins, RW, Clarke, J, Shawron, K, Keshavarzian, A, Walter, J
Microbiome. 2018;6(1):121
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Numerous studies have established that the gut microbiota contributes to gastrointestinal health and this can also be achieved through dietary consumption of probiotics and prebiotics. Gut microbiota have also been associated in impacting the markers of metabolic diseases but not many studies are available. Henceforth on this basis this study, looked into the synergistic effects of administering prebiotic together with a select probiotic Bifidobacterium strain. The main objective of this study was to establish the synergistic effect of probiotics and prebiotics and compare their effects on microbiota composition. This study was a randomised, double-blinded, placebo-controlled, clinical trial conducted on a total of 151 volunteers assigned to six treatments groups. The authors concluded that the synergistic combinations tested in this study did not demonstrate functional synergism, and neither any significant effects on metabolic disease outcomes were observed within the six treatment groups. Although, the findings from this study clearly demonstrated that the pro and prebiotic components improved markers of colonic permeability, henceforth providing a rational for their use in gut microbiota health.
Abstract
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.
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Long-term effects of provided low and high glycemic load low energy diets on mood and cognition.
Cheatham, RA, Roberts, SB, Das, SK, Gilhooly, CH, Golden, JK, Hyatt, R, Lerner, D, Saltzman, E, Lieberman, HR
Physiology & behavior. 2009;98(3):374-9
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Previous studies have shown a difference between low glycaemic index (GI) and high GI energy restricted diets on mood and cognition. This randomised trial of 46 healthy overweight individuals aimed to assess the long-term effects of LG or HG energy restricted diet on mood and cognition function. Individuals were randomly assigned to a low GI or a high GI diet with caloric restriction for 12 months. The study did not observe any difference in cognitive function of individuals assigned to either the low GI or the high GI diet but it did show a beneficial effect of low GI diet on subclinical depression. The results of this small study were consistent with previous studies where low GI diets may be protective against negative mood change during weight loss whereas negative changes occur if a conventional high GI diet is consumed.
Abstract
Energy-restricted low glycemic load diets are being used increasingly for weight loss. However, the long-term effects of such regimens on mood and cognitive performance are not known. We assessed the effects of low glycemic load (LG) and high glycemic load (HG) energy-restricted diets on mood and cognitive performance during 6 months of a randomized controlled trial when all food was provided. Subjects were 42 healthy overweight adults (age 35+/-5 years; BMI 27.8+/-1.6 kg/m(2)) with a mean weight loss of 8.7+/-5.0% that did not differ significantly by diet randomization. Mood was assessed by using the Profile of Mood States (POMS) questionnaire. Cognitive performance was assessed by using computerized tests of simple reaction time, vigilance, learning, short-term memory and attention, and language-based logical reasoning. Worsening mood outcome over time was observed in the HG diet group compared to the LG for the depression subscale of POMS (p=0.009 after including hunger as a covariate). There was no significant change over time in any cognitive performance values. These findings suggest a negative effect of an HG weight loss diet on sub-clinical depression but, in contrast to a previous suggestion, provide no support for differential effects of LG versus HD diets on cognitive performance.