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Impact of wheat aleurone on biomarkers of cardiovascular disease, gut microbiota and metabolites in adults with high body mass index: a double-blind, placebo-controlled, randomized clinical trial.
Fava, F, Ulaszewska, MM, Scholz, M, Stanstrup, J, Nissen, L, Mattivi, F, Vermeiren, J, Bosscher, D, Pedrolli, C, Tuohy, KM
European journal of nutrition. 2022;61(5):2651-2671
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Cross-sectional studies have shown that whole grain cereal consumption can reduce the risk of cardiovascular disease (CVD, as well as reduce systemic inflammation, which is linked to many chronic diet associated diseases. Aleurone is a wheat grain fraction composed of a single cell layer that constitutes the outermost portion of the endosperm and contains many of the beneficial substances. The primary aim of this study was to investigate the effect of aleurone consumption on plasma homocysteine concentrations in overweight/ obese subjects. Secondary aim was to measure the impact of chronic aleurone supplementation on markers of CVD risk and on the human gut microbiota and its metabolic output. This study is a placebo-controlled, randomised, double-blind parallel trial with 2 test foods, wheat aleurone-rich foods or placebo foods (cellulose). Participants (n=74) were randomised to receive the active supplementation (aleurone 27 g per day) or placebo for 4 consecutive weeks. Results show that although average plasma homocysteine levels decreased upon wheat aleurone supplementation treatment, this change was not statistically significant, and homocysteine levels did not differ between groups after intervention. Furthermore, there was a significant increase in bifidobacteria both over time and compared to the placebo. Several significant and useful biomarkers of wheat aleurone intake, all related to wheat polyphenol metabolism by the gut microbiota, were identified. Authors conclude that wheat aleurone supplementation has the potential to modulate the gut microbial metabolic output and increase faecal bifidobacterial abundance, but it does not impact plasma homocysteine or other CVD biomarkers.
Abstract
PURPOSE Aleurone is a cereal bran fraction containing a variety of beneficial nutrients including polyphenols, fibers, minerals and vitamins. Animal and human studies support the beneficial role of aleurone consumption in reducing cardiovascular disease (CVD) risk. Gut microbiota fiber fermentation, polyphenol metabolism and betaine/choline metabolism may in part contribute to the physiological effects of aleurone. As primary objective, this study evaluated whether wheat aleurone supplemented foods could modify plasma homocysteine. Secondary objectives included changes in CVD biomarkers, fecal microbiota composition and plasma/urine metabolite profiles. METHODS A parallel double-blind, placebo-controlled and randomized trial was carried out in two groups of obese/overweight subjects, matched for age, BMI and gender, consuming foods supplemented with either aleurone (27 g/day) (AL, n = 34) or cellulose (placebo treatment, PL, n = 33) for 4 weeks. RESULTS No significant changes in plasma homocysteine or other clinical markers were observed with either treatment. Dietary fiber intake increased after AL and PL, animal protein intake increased after PL treatment. We observed a significant increase in fecal Bifidobacterium spp with AL and Lactobacillus spp with both AL and PL, but overall fecal microbiota community structure changed little according to 16S rRNA metataxonomics. Metabolomics implicated microbial metabolism of aleurone polyphenols and revealed distinctive biomarkers of AL treatment, including alkylresorcinol, cinnamic, benzoic and ferulic acids, folic acid, fatty acids, benzoxazinoid and roasted aroma related metabolites. Correlation analysis highlighted bacterial genera potentially linked to urinary compounds derived from aleurone metabolism and clinical parameters. CONCLUSIONS Aleurone has potential to modulate the gut microbial metabolic output and increase fecal bifidobacterial abundance. However, in this study, aleurone did not impact on plasma homocysteine or other CVD biomarkers. TRIAL REGISTRATION The study was registered at ClinicalTrials.gov (NCT02067026) on the 17th February 2014.
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Fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), but not gluten, elicit modest symptoms of irritable bowel syndrome: a double-blind, placebo-controlled, randomized three-way crossover trial.
Nordin, E, Brunius, C, Landberg, R, Hellström, PM
The American journal of clinical nutrition. 2022;115(2):344-352
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Irritable bowel syndrome (IBS) is a chronic functional bowel disorder that is characterised by recurring abdominal pain over ≥3 months within a 6-month period in association with altered bowel habits. Symptomatic treatment of IBS includes dietary adaptation, with a focus on prebiotics, probiotics, gluten, and fermentable oligo-, di-, monosaccharides and polyols (FODMAPs). The main aim of this study was to investigate the effects of weeklong interventions with high intakes of a wide range of FODMAPs, gluten, or a nonfermentable placebo in subjects with moderate to severe IBS. This study is a double-blind, placebo-controlled, randomised 3-way study with triple crossover design. One-hundred and ten participants were enrolled and randomly assigned for the study. Results show that a mixture of widely consumed FODMAPs caused only modest worsening of gastrointestinal symptoms compared with gluten and placebo. Authors conclude that there were interindividual variability in the intervention responses. Thus, future studies should investigate these differences to understand possible underlying disease mechanisms.
Abstract
BACKGROUND Irritable bowel syndrome (IBS) has been associated with diets rich in fermentable oligo-, di-, monosaccharides, and polyols (FODMAPs), and gluten. Most previous studies have been single-blind and have focused on the elimination of FODMAPs or provocation with single FODMAPs. The effect of gluten is unclear, large trials isolating the effect of gluten from that of FODMAPs are needed. OBJECTIVES The aims of this study were to ensure high intakes of a wide range of FODMAPs, gluten, or placebo, and to evaluate the effects on IBS symptoms using the IBS-severity scoring system (IBS-SSS). METHODS The study was carried out with a double-blind, placebo-controlled, randomized 3-way crossover design in a clinical facility in Uppsala from September 2018 to June 2019. In all, 110 participants fulfilling the IBS Rome IV criteria, with moderate to severe IBS, were randomly assigned; 103 (90 female, 13 male) completed the trial. Throughout, IBS participants maintained a diet with minimal FODMAP content and no gluten. Participants were block-randomly assigned to 1-wk interventions with FODMAPs (50 g/d), gluten (17.3 g/d), or placebo, separated by 1-wk washout. All participants who completed ≥1 intervention were included in the intention-to-treat analysis. RESULTS In participants with IBS (n = 103), FODMAPs caused higher IBS-SSS scores (mean 240 [95% CI: 222, 257]) than placebo (198 [180, 215]; P = 0.00056) or gluten (208 [190, 226]; P = 0.013); no differences were found between the placebo and gluten groups (P = 1.0). There were large interindividual differences in IBS-SSS scores associated with treatment. No adverse events were reported. CONCLUSION In participants with IBS, FODMAPs had a modest effect on typical IBS symptoms, whereas gluten had no effect. The large interindividual differences in responses to the interventions warrant further detailed studies to identify possible underlying causes and enable individual prediction of responses. This trial was registered at www.clinicaltrials.gov as NCT03653689.
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Mixed Spices at Culinary Doses Have Prebiotic Effects in Healthy Adults: A Pilot Study.
Lu, QY, Rasmussen, AM, Yang, J, Lee, RP, Huang, J, Shao, P, Carpenter, CL, Gilbuena, I, Thames, G, Henning, SM, et al
Nutrients. 2019;11(6)
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An increasing body of evidence suggests that the gut microbiota has a profound impact on human health. While the microbiome of a healthy individual is relatively stable, gut microbial dynamics can be influenced by host lifestyle and dietary choices. The aim of this study was to investigate the effects of mixed spices (cinnamon, oregano, ginger, black pepper, and cayenne pepper) at culinary doses consumed over 2 weeks in a standardized 5g capsule on the production of gut microbiota and short-chain fatty acids The study is a randomised, placebo-controlled, double-blind pilot study carried out with a total of 31 healthy women and men aged between 18 and 65. The subjects were randomly allocated to one of the two intervention groups. Results indicate that daily intake of 5g of mixed spices for 2 weeks in healthy subjects resulted in a significant reduction in the relative abundance of the phylum Firmicutes (bacteria), and a trend of increasing in phylum Bacteroidetes (bacteria) as compared with a matched control group. Authors conclude that a mixture of spices at culinary doses affects the composition of gut microbiota.
Abstract
Spices were used as food preservatives prior to the advent of refrigeration, suggesting the possibility of effects on microbiota. Previous studies have shown prebiotic activities in animals and in vitro, but there has not been a demonstration of prebiotic or postbiotic effects at culinary doses in humans. In this randomized placebo-controlled study, we determined in twenty-nine healthy adults the effects on the gut microbiota of the consumption daily of capsules containing 5 g of mixed spices at culinary doses by comparison to a matched control group consuming a maltodextrin placebo capsule. The 16S ribosomal RNA sequencing data were used for microbial characterization. Spice consumption resulted in a significant reduction in Firmicutes abundance (p < 0.033) and a trend of enrichment in Bacteroidetes (p < 0.097) compared to placebo group. Twenty-six operational taxonomic units (OTUs) were different between the spice and placebo groups after intervention. Furthermore, there was a significant negative correlation between fecal short-chain fatty acid propionate concentration and Firmicutes abundance in spice intervention group (p < 0.04). The production of individual fecal short-chain fatty acid was not significantly changed by spice consumption in this study. Mixed spices consumption significantly modified gut microbiota, suggesting a prebiotic effect of spice consumption at culinary doses.