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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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Increased Colonic Permeability and Lifestyles as Contributing Factors to Obesity and Liver Steatosis.
Di Palo, DM, Garruti, G, Di Ciaula, A, Molina-Molina, E, Shanmugam, H, De Angelis, M, Portincasa, P
Nutrients. 2020;12(2)
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Intestinal permeability (IP) is dependent on the structure and function of the intestinal barrier. The gut barrier integrity is the result of ongoing equilibrium and crosstalk involving the microbiome, the mucus, the enterocytes [intestinal absorptive cells], the gut immune system, and the gut–vascular barrier. The main aim of this study was to explore the pan-enteric IP (stomach, small intestine, and colon) with respect to size and fat distribution, as well as the presence of liver steatosis. The study is a cohort study that examined 120 subjects (obese n = 45, overweight n=30, normal weight n = 45). Groups were gender-matched except for the prevalence of males in the overweight group. Results highlight the existence of an association between colonic (but not stomach and small intestinal) permeability, obesity, and liver steatosis. Findings show that: - liver steatosis was detected in 69 (57.5%) subjects, of which 36 (52%) were males. The prevalence of liver steatosis increased from 4% in normal weight subjects to 77%, and to 98% in overweight and obese subjects, respectively. - gastrointestinal permeability changed between age groups at every tract, whereas stomach and small intestine IP decreased with age. Furthermore, this finding also occurred in subjects aged over or equal to 65 years, with respect to colonic permeability. Authors conclude that further studies must evaluate the possibility of modulating colonic permeability to allow both primary prevention measures and new therapeutic strategies in metabolic and liver diseases.
Abstract
Intestinal permeability (IP) is essential in maintaining gut-metabolic functions in health. An unequivocal evaluation of IP, as marker of intestinal barrier integrity, however, is missing in health and in several diseases. We aimed to assess IP in the whole gastrointestinal tract according to body mass index (BMI) and liver steatosis. In 120 patients (61F:59M; mean age 45 ± SEM 1.2 years, range: 18-75), IP was distinctively studied by urine recovery of orally administered sucrose (SO, stomach), lactulose/mannitol ratio (LA/MA, small intestine), and sucralose (SA, colon). By triple quadrupole mass-spectrometry and high-performance liquid chromatography, we measured urinary recovery of saccharide probes. Subjects were stratified according to BMI as normal weight, overweight, and obesity, and answered questionnaires regarding dietary habits and adherence to the Mediterranean Diet. Liver steatosis was assessed by ultrasonography. IP at every gastrointestinal tract was similar in both sexes and decreased with age. Stomach and small intestinal permeability did not differ according to BMI. Colonic permeability increased with BMI, waist, neck, and hip circumferences and was significantly higher in obese than in lean subjects. As determined by logistic regression, the odds ratio (OR) of BMI increment was significantly higher in subjects in the highest tertile of sucralose excretion, also after adjusting for age and consumption of junk food. The presence of liver steatosis was associated with increased colonic permeability. Patients with lower score of adherence to Mediterranean diet had a higher score of 'junk food'. Intestinal permeability tended to increase in subjects with a lower adherence to Mediterranean diet. In conclusion, colonic (but not stomach and small intestinal) permeability seems to be linked to obesity and liver steatosis independently from dietary habits, age, and physical activity. The exact role of these last factors, however, requires specific studies focusing on intestinal permeability. Results should pave the way to both primary prevention measures and new therapeutic strategies in metabolic and liver diseases.
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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.