Archive

Research Area: Gut Health

Effect of nuts on gastrointestinal health. 

Mandalari, G., T. Gervasi, D.W. Rosenberg, K.G. Lapsley, D.J. Baer, 2023. Effect of nuts on gastrointestinal health. Nutrients. 15(7):1733. https://doi.org/10.3390/nu15071733

Nuts are high nutrient-dense foods containing healthy lipids, dietary fiber, and bioactive phytochemicals, including vitamins and minerals. Although the beneficial effect of nut consumption on different chronic diseases has been well documented, especially in relation to their cardiometabolic benefits, less scientific evidence is available on their possible beneficial effects on gastrointestinal health. In this narrative review, we summarize the most important findings and new research perspectives in relation to the importance of nut consumption on gastrointestinal health. The integrity of the cell wall structure, cell size and particle size after mastication are known to play a crucial role in energy, nutrient and bioactive release from nuts during digestion, therefore affecting bioaccessibility. Other mechanisms, such as cell wall composition, thickness and porosity, as well as stability of the membranes surrounding the oil bodies within the cell, are also important for energy extraction. As the undigested nutrients and phytochemicals are delivered to the colon, effects on gut microbiota composition are predicted. Although the overall effect of nut consumption on microbial alpha- and beta-diversity has been inconsistent, some scientific evidence suggests an increase in fecal butyrate after almond consumption, and a beneficial role of walnuts on the prevention of ulcerative colitis and protection against the development of gastric mucosal lesions.

The impact of almonds and almond processing on gastrointestinal physiology, luminal microbiology, and gastrointestinal symptoms: a randomized controlled trial and mastication study.

Creedon, A. C., E. Dimidi, E.S. Hung, M. Rossi, C. Probert, T. Grassby, J. Miguens-Blanco, J.R. Marchesi, S.M. Scott, S.E. Berry, K. Whelan, 2022. The impact of almonds and almond processing on gastrointestinal physiology, luminal microbiology, and gastrointestinal symptoms: a randomized controlled trial and mastication study. Am. J. Clin. Nutr. 116(6):1790–1804. https://doi.org/10.1093/ajcn/nqac265

Background: Almonds contain lipid, fiber, and polyphenols and possess physicochemical properties that affect nutrient bioaccessibility, which are hypothesized to affect gut physiology and microbiota. Objectives: To investigate the impact of whole almonds and ground almonds (almond flour) on fecal bifidobacteria (primary outcome), gut microbiota composition, and gut transit time. Methods: Healthy adults (n = 87) participated in a parallel, 3-arm randomized controlled trial. Participants received whole almonds (56 g/d), ground almonds (56 g/d), or an isocaloric control in place of habitual snacks for 4 wk. Gut microbiota composition and diversity (16S rRNA gene sequencing), SCFAs (GC), volatile organic compounds (GC-MS), gut transit time (wireless motility capsule), stool output and gut symptoms (7-d diary) were measured at baseline and endpoint. The impact of almond form on particle size distribution (PSD) and predicted lipid release was measured (n = 31). Results: Modified intention-to-treat analysis was performed on 79 participants. There were no significant differences in mean ± SD abundance of fecal bifidobacteria after consumption of whole almonds (8.7% ± 7.7%), ground almonds (7.8% ± 6.9%), or control (13.0% ± 10.2%; q = 0.613). Consumption of almonds (whole and ground pooled) resulted in higher mean ± SD butyrate (24.1 ± 15.0 μmol/g) than control (18.2 ± 9.1 μmol/g; P = 0.046). There was no effect of almonds on gut microbiota at the phylum level or diversity, gut transit time, stool consistency, or gut symptoms. Almond form (whole compared with ground) had no effect on study outcomes. Ground almonds resulted in significantly smaller PSD and higher mean ± SD predicted lipid release (10.4% ± 1.8%) than whole almonds (9.3% ± 2.0%; P = 0.017). Conclusions: Almond consumption has limited impact on microbiota composition but increases butyrate in adults, suggesting positive alterations to microbiota functionality. Almonds can be incorporated into the diet to increase fiber consumption without gut symptoms.This trial was registered at clinicaltrials.gov as NCT03581812.

The effects of the Green-Mediterranean diet on cardiometabolic health are linked to gut microbiome modifications: a randomized controlled trial. 

Rinott, E., A.Y. Meir, G. Tsaban, H. Zelicha, A. Kaplan, D. Knights, K. Tuohy, M.U. Scholz, O. Koren, M.J. Stampfer, D.D. Wang, I. Shai, I. Youngster, 2022. The effects of the Green-Mediterranean diet on cardiometabolic health are linked to gut microbiome modifications: a randomized controlled trial. Genome Med. 14(1):29. https://doi.org/10.1186/s13073-022-01015-z

Background: Previous studies have linked the Mediterranean diet (MED) with improved cardiometabolic health, showing preliminary evidence for a mediating role of the gut microbiome. We recently suggested the Green-Mediterranean (Green-MED) diet as an improved version of the healthy MED diet, with increased consumption of plant-based foods and reduced meat intake. Here, we investigated the effects of MED interventions on the gut microbiota and cardiometabolic markers, and the interplay between the two, during the initial weight loss phase of the DIRECT-PLUS trial. Methods: In the DIRECT-PLUS study, 294 participants with abdominal obesity/dyslipidemia were prospectively randomized to one of three intervention groups: healthy dietary guidelines (standard science-based nutritional counseling), MED, and Green-MED. Both isocaloric MED and Green-MED groups were supplemented with 28g/day walnuts. The Green-MED group was further provided with daily polyphenol-rich green tea and Mankai aquatic plant (new plant introduced to a western population). Gut microbiota was profiled by 16S rRNA for all stool samples and shotgun sequencing for a select subset of samples. Results: Both MED diets induced substantial changes in the community structure of the gut microbiome, with the Green-MED diet leading to more prominent compositional changes, largely driven by the low abundant, “non-core,” microorganisms. The Green-MED diet was associated with specific microbial changes, including enrichments in the genus Prevotella and enzymatic functions involved in branched-chain amino acid degradation, and reductions in the genus Bifidobacterium and enzymatic functions responsible for branched-chain amino acid biosynthesis. The MED and Green-MED diets were also associated with stepwise beneficial changes in body weight and cardiometabolic biomarkers, concomitantly with the increased plant intake and reduced meat intake. Furthermore, while the level of adherence to the Green-MED diet and its specific green dietary components was associated with the magnitude of changes in microbiome composition, changes in gut microbial features appeared to mediate the association between adherence to the Green-MED and body weight and cardiometabolic risk reduction. Conclusions: Our findings support a mediating role of the gut microbiome in the beneficial effects of the Green-MED diet enriched with Mankai and green tea on cardiometabolic risk factors.

Transcriptome profiling analysis of the response to walnut polyphenol extract in Helicobacter pylori-infected cells.

Park, J.M., Y.M. Han, H.J. Lee, S.J. Hwang, S.J. Kim, K.B. Hahm, 2021. Transcriptome profiling analysis of the response to walnut polyphenol extract in Helicobacter pylori-infected cells. J Clin Biochem Nutr. doi.org/10.3164/jcbn.20-128.

Dietary intervention to prevent Helicobacter pylori (H. pylori)-associated gastric diseases seems to be ideal with no risk of bacterial resistance, safe long-term intervention, and correcting pathogenic mechanisms including rejuvenation of precancerous atrophic gastritis and anti-mutagenesis. A transcriptome as set of all RNAs transcribed by certain tissues or cells demonstrates gene functions and reveals the molecular mechanism of specific biological processes against diseases. Here, we have performed RNAseq and bioinformatic analysis to explain proof of concept that walnut intake can rescue from H. pylori infection and explore unidentified mode of actions of walnut polyphenol extract (WPE). As results, BIRC3, SLC25A4, f3 transcription, VEGFA, AZU1, HMOX1, RAB3A, RELBTNIP1, ETFB, INPP5J, PPME1, RHOB, TPI1, FOSL1, JUND.RELB, KLF2, MUC1, NDRG1, ALDOA, ENO1, PFKP, GPI, GDF15, and NRTN genes were newly discovered to be enriched with WPE, whereas CCR4, BLNK, CCR7, CXCR4, CDO1, KLSG1, SELE, RASGRP2, PIK3R3, TSPAN32, HOXC-AS3, HCG8, BTNL8, and CXCL3 genes as inhibitory targets by WPE in H. pylori infection. We identified additional genes what WPE afforded actions of avoiding H. pylori-driven onco-inflammation and rejuvenating precancerous atrophic gastritis. Conclusively, after applying RNAseq analysis in order to document walnut intake for precision medicine against H. pylori infection, significant transcriptomic profiling applicable for validation were drawn.

Neural correlates of future weight loss reveal a possible role for brain-gastric interactions.

Levakov, G., A. Kaplan, A. Yaskolka Meir, E. Rinott, G. Tsaban, H. Zelicha, N. Meiran, I. Shelef, I. Shai, G. Avidan, 2021. Neural correlates of future weight loss reveal a possible role for brain-gastric interactions. Neuroimage. 224:117403. doi: 10.1016/j.neuroimage.2020.117403.

Lifestyle dietary interventions are an essential practice in treating obesity, hence neural factors that may assist in predicting individual treatment success are of great significance. Here, in a prospective, open-label, three arms study, we examined the correlation between brain resting-state functional connectivity measured at baseline and weight loss following 6 months of lifestyle intervention in 92 overweight participants. We report a robust subnetwork composed mainly of sensory and motor cortical regions, whose edges correlated with future weight loss. This effect was found regardless of intervention group. Importantly, this main finding was further corroborated using a stringent connectivity-based prediction model assessed with cross-validation thus attesting to its robustness. The engagement of senso-motor regions in this subnetwork is consistent with the over-sensitivity to food cues theory of weight regulation. Finally, we tested an additional hypothesis regarding the role of brain-gastric interaction in this subnetwork, considering recent findings of a cortical network synchronized with gastric activity. Accordingly, we found a significant spatial overlap with the subnetwork reported in the present study. Moreover, power in the gastric basal electric frequency within our reported subnetwork negatively correlated with future weight loss. This finding was specific to the weight loss related subnetwork and to the gastric basal frequency. These findings should be further corroborated by combining direct recordings of gastric activity in future studies. Taken together, these intriguing results may have important implications for our understanding of the etiology of obesity and the mechanism of response to dietary intervention.

Effects of diet-modulated autologous fecal microbiota transplantation on weight regain.

Rinott, E., I. Youngster, A.Y. Meir, G. Tsaban, H. Zelicha, A. Kaplan, D. Knights, K. Tuohy, F. Fava, M.U. Scholz, O. Ziv, E. Reuven, A. Tirosh, A. Rudich, M. Blüher, M. Stumvoll, U. Ceglarek, K. Clement, O. Koren, D.D. Wang, F.B. Hu, M.J. Stampfer, I. Shai, 2021. Effects of diet-modulated autologous fecal microbiota transplantation on weight regain. Gastroenterology. 160(1):158–173.

Background & Aims: We evaluated the efficacy and safety of diet-modulated autologous fecal microbiota transplantation (aFMT) for treatment of weight regain after the weight loss phase. Methods: In the DIRECT-PLUS weight loss trial (May 2017 through July 2018), abdominally obese or dyslipidemic participants in Israel were randomly assigned to (1) healthy dietary guidelines, (2) Mediterranean diet, and (3) green-Mediterranean diet weight-loss groups. All groups received free gym membership and physical activity guidelines. Both iso-caloric Mediterranean groups consumed 28g/day walnuts (+440mg/d polyphenols provided). The green-Mediterranean dieters further consumed green tea (3-4 cups/day) and a Wolffia-globosa (Mankai strain;100g/day) green shake (+800mg/day polyphenols provided). After 6 months (weight-loss phase), 90 eligible participants (mean age, 52 years; mean weight loss, 8.3 kg) provided a fecal sample that was processed into aFMT by frozen, opaque and odorless capsules. The participants were then randomly assigned to groups that received 100 capsules containing their own fecal microbiota or placebo until month 14. The primary outcome was regain of the lost weight over the expected weight regain phase (months 6–14). Secondary outcomes were gastrointestinal symptoms, waist-circumference, glycemic status and changes in the gut microbiome, as measured by metagenomic sequencing and 16s-rRNA. We validated the results in a parallel in-vivo study of mice specifically fed with Mankai, as compared to control chow diet. Results: Of the 90 participants in the aFMT trial, 96% ingested at least 80 of 100 oral aFMT or placebo frozen capsules over the transplantation period. No aFMTrelated adverse events or symptoms were observed. For the primary outcome, although no significant differences in weight regain were observed among the participants in the different lifestyle interventions during months 6–14 (aFMT, 30.4% vs. placebo, 40.6%;P=.28), aFMT significantly attenuated weight regain in the green Mediterranean group (aFMT, 17.1%, vs placebo, 50%; P=.02), but not in the dietary guidelines (P=.57) or Mediterranean diet (P=.64) groups (P for the interaction=.03). Accordingly, aFMT attenuated waist circumference gain (aFMT, 1.89cm vs placebo, 5.05cm;P=.01) and insulin rebound (aFMT, 1.46±3.6µIU/ml vs placebo, 1.64±4.7µIU/ml;P=.04) in the green Mediterranean group but not in the dietary guidelines or Mediterranean diet (P for the interaction=.04 and .03, respectively). The green-Mediterranean diet was the only intervention to induce a significant change in microbiome composition during the weight loss phase, and to prompt preservation of weight loss-associated specific bacteria and microbial metabolic pathways (mainly microbial sugar transport) following the aFMT. In mice, Mankai modulated aFMT in the weight loss phase, compared with control diet aFMT, significantly prevented weight regain, and resulted in better glucose tolerance, during a high-fat-diet induced regain phase (P<.05 for all). Conclusions: Autologous FMT, collected during the weight loss phase and administrated in the regain phase, might preserve weight loss and glycemic control and is associated with specific microbiome signatures. High-polyphenols, green plant-based or Mankai diet better optimizes the microbiome for an aFMT procedure.

Neural correlates of future weight loss reveal a possible role for brain-gastric interactions.

Levakov G, Kaplan A, Yaskolka Meir A, Rinott E, Tsaban G, Zelicha H, Meiran N, Shelef I, Shai I, Avidan G., 2021. Neural correlates of future weight loss reveal a possible role for brain-gastric interactions. Neuroimage. 224:117403. doi: 10.1016/j.neuroimage.2020.117403.

Lifestyle dietary interventions are an essential practice in treating obesity, hence neural factors that may assist in predicting individual treatment success are of great significance. Here, in a prospective, open-label, three arms study, we examined the correlation between brain resting-state functional connectivity measured at baseline and weight loss following 6 months of lifestyle intervention in 92 overweight participants. We report a robust subnetwork composed mainly of sensory and motor cortical regions, whose edges correlated with future weight loss. This effect was found regardless of intervention group. Importantly, this main finding was further corroborated using a stringent connectivity-based prediction model assessed with cross-validation thus attesting to its robustness. The engagement of senso-motor regions in this subnetwork is consistent with the over-sensitivity to food cues theory of weight regulation. Finally, we tested an additional hypothesis regarding the role of brain-gastric interaction in this subnetwork, considering recent findings of a cortical network synchronized with gastric activity. Accordingly, we found a significant spatial overlap with the subnetwork reported in the present study. Moreover, power in the gastric basal electric frequency within our reported subnetwork negatively correlated with future weight loss. This finding was specific to the weight loss related subnetwork and to the gastric basal frequency. These findings should be further corroborated by combining direct recordings of gastric activity in future studies. Taken together, these intriguing results may have important implications for our understanding of the etiology of obesity and the mechanism of response to dietary intervention.

Walnuts and vegetable oils containing oleic acid differentially affect the gut microbiota and associations with cardiovascular risk factors: Follow-up of a randomized, controlled, feeding trial in adults at risk for cardiovascular disease.

Tindall, A.M., C.J. McLimans, K.S. Petersen, P.M. Kris-Etherton, R. Lamendella, 2020. Walnuts and vegetable oils containing oleic acid differentially affect the gut microbiota and associations with cardiovascular risk factors: Follow-up of a randomized, controlled, feeding trial in adults at risk for cardiovascular disease. J Nutr. 2020;150(4):806-817.

Background: It is unclear whether the favorable effects of walnuts on the gut microbiota are attributable to the fatty acids, including α-linolenic acid (ALA), and/or the bioactive compounds and fiber. Objective: This study examined between-diet gut bacterial differences in individuals at increased cardiovascular risk following diets that replace SFAs with walnuts or vegetable oils. Methods: Forty-two adults at cardiovascular risk were included in a randomized, crossover, controlled-feeding trial that provided a 2-wk standard Western diet (SWD) run-in and three 6-wk isocaloric study diets: a diet containing whole walnuts (WD; 57-99 g/d walnuts; 2.7% ALA), a fatty acid-matched diet devoid of walnuts (walnut fatty acid-matched diet; WFMD; 2.6% ALA), and a diet replacing ALA with oleic acid without walnuts (oleic acid replaces ALA diet; ORAD; 0.4% ALA). Fecal samples were collected following the run-in and study diets to assess gut microbiota with 16S rRNA sequencing and Qiime2 for amplicon sequence variant picking. Results: Subjects had elevated BMI (30 ± 1 kg/m2), blood pressure (121 ± 2/77 ± 1 mmHg), and LDL cholesterol (120 ± 5 mg/dL). Following the WD, Roseburia [relative abundance (RA) = 4.2%, linear discriminant analysis (LDA) = 4], Eubacterium eligensgroup (RA = 1.4%, LDA = 4), LachnospiraceaeUCG001 (RA = 1.2%, LDA = 3.2), Lachnospiraceae UCG004 (RA = 1.0%, LDA = 3), and Leuconostocaceae (RA = 0.03%, LDA = 2.8) were most abundant relative to taxa in the SWD (P ≤ 0.05 for all). The WD was also enriched in Gordonibacter relative to the WFMD. Roseburia (3.6%, LDA = 4) and Eubacterium eligensgroup (RA = 1.5%, LDA = 3.4) were abundant following the WFMD, and Clostridialesvadin BB60group (RA = 0.3%, LDA = 2) and gutmetagenome (RA = 0.2%, LDA = 2) were most abundant following the ORAD relative to the SWD (P ≤ 0.05 for all). Lachnospiraceae were inversely correlated with blood pressure and lipid/lipoprotein measurements following the WD. Conclusions: The results indicate similar enrichment of Roseburia following the WD and WFMD, which could be explained by the fatty acid composition. Gordonibacter enrichment and the inverse association between Lachnospiraceae and cardiovascular risk factors following the WD suggest that the gut microbiota may contribute to the health benefits of walnut consumption in adults at cardiovascular risk. This trial was registered at clinicaltrials.gov as NCT02210767.

Effects of diet-modulated autologous fecal microbiota transplantation on weight regain.

Rinott, E., I. Youngster, A.Y. Meir, G. Tsaban, H. Zelicha, A. Kaplan, D. Knights, K. Tuohy, F. Fava, M.U. Scholz, O. Ziv, E. Reuven, A. Tirosh, A. Rudich, M. Blüher, M. Stumvoll, U. Ceglarek, K. Clement, O. Koren, D.D. Wang, F.B. Hu, M.J. Stampfer, I. Shai, 2020. Effects of diet-modulated autologous fecal microbiota transplantation on weight regain. Gastroenterology. doi: https:// doi.org/10.1053/j.gastro.2020.08.041.

Background & Aims: We evaluated the efficacy and safety of diet-modulated autologous fecal microbiota transplantation (aFMT) for treatment of weight regain after the weight loss phase. Methods: In the DIRECT-PLUS weight loss trial (May 2017 through July 2018), abdominally obese or dyslipidemic participants in Israel were randomly assigned to (1) healthy dietary guidelines, (2) Mediterranean diet, and (3) green-Mediterranean diet weight-loss groups. All groups received free gym membership and physical activity guidelines. Both iso-caloric Mediterranean groups consumed 28g/day walnuts (+440mg/d polyphenols provided). The green-Mediterranean dieters further consumed green tea (3-4 cups/day) and a Wolffia-globosa (Mankai strain;100g/day) green shake (+800mg/day polyphenols provided). After 6 months (weight-loss phase), 90 eligible participants (mean age, 52 years; mean weight loss, 8.3 kg) provided a fecal sample that was processed into aFMT by frozen, opaque and odorless capsules. The participants were then randomly assigned to groups that received 100 capsules containing their own fecal microbiota or placebo until month 14. The primary outcome was regain of the lost weight over the expected weight regain phase (months 6–14). Secondary outcomes were gastrointestinal symptoms, waist-circumference, glycemic status and changes in the gut microbiome, as measured by metagenomic sequencing and 16s-rRNA. We validated the results in a parallel in-vivo study of mice specifically fed with Mankai, as compared to control chow diet. Results: Of the 90 participants in the aFMT trial, 96% ingested at least 80 of 100 oral aFMT or placebo frozen capsules over the transplantation period. No aFMTrelated adverse events or symptoms were observed. For the primary outcome, although no significant differences in weight regain were observed among the participants in the different lifestyle interventions during months 6–14 (aFMT, 30.4% vs. placebo, 40.6%;P=.28), aFMT significantly attenuated weight regain in the green Mediterranean group (aFMT, 17.1%, vs placebo, 50%; P=.02), but not in the dietary guidelines (P=.57) or Mediterranean diet (P=.64) groups (P for the interaction=.03). Accordingly, aFMT attenuated waist circumference gain (aFMT, 1.89cm vs placebo, 5.05cm;P=.01) and insulin rebound (aFMT, 1.46±3.6µIU/ml vs placebo, 1.64±4.7µIU/ml;P=.04) in the green Mediterranean group but not in the dietary guidelines or Mediterranean diet (P for the interaction=.04 and .03, respectively). The green-Mediterranean diet was the only intervention to induce a significant change in microbiome composition during the weight loss phase, and to prompt preservation of weight loss-associated specific bacteria and microbial metabolic pathways (mainly microbial sugar transport) following the aFMT. In mice, Mankaimodulated aFMT in the weight loss phase, compared with control diet aFMT, significantly prevented weight regain, and resulted in better glucose tolerance, during a high-fat-diet induced regain phase (P<.05 for all). Conclusions: Autologous FMT, collected during the weight loss phase and administrated in the regain phase, might preserve weight loss and glycemic control and is associated with specific microbiome signatures. High-polyphenols, green plant-based or Mankai diet better optimizes the microbiome for an aFMT procedure.

Dietary walnut as food factor to rescue from NSAID-induced gastrointestinal mucosal damages.

An, J.M., E.H., Kim, H. Le, H.J. Lee, K.B. Hahm, 2020. Dietary walnut as food factor to rescue from NSAID-induced gastrointestinal mucosal damages. Arch Biochem Biophys. 689:108466. doi:10.1016/j.abb.2020.108466.

Nuclear factor erythroid-derived 2-like 2 (Nrf-2) is transcription factor implicated in the antioxidant response element-mediated induction of endogenous antioxidant enzyme such as heme oxygenase-1 (HO-1), glutamatecysteine ligase, and NAD(P)H quinone dehydrogenase 1, among which HO-1 is an enzyme catalyzing the degradation of heme.producing biliverdin, ferrous iron, and carbon monoxide. In the stomach, as much as regulating gastric acid secretions, well-coordinated establishment of defense system stands for maintaining gastric integrity. In previous study, author et al. for the first time discovered HO-1 induction was critical in affording faithful gastric defense against various irritants including Helicobacter pylori infection, stress, alcohol, nonsteroidal anti-inflammatory drugs (NSAIDs), aspirin, and toxic bile acids. In this review article, we can add the novel evidence that dietary walnut intake can be reliable way to rescue from NSAIDs-induced gastrointestinal damages via the induction of HO-1 transcribed with Nrf-2 through specific inactivation of Keap-1. From molecular exploration to translational animal model of indomethacin-induced gastrointestinal damages, significant induction of HO-1 contributed to rescuing from damages. In addition to HO-1 induction action relevant to walnut, we added the description the general actions of walnut extracts or dietary intake of walnut regarding cytoprotection and why we have focused on to NSAID damages.