Increased bioavailability of plasma polyphenols via the intestinal fermentation of soybean fibers: a role for gut microbiome?

Increased bioavailability of plasma polyphenols via the intestinal fermentation of soybean fibers: a role for gut microbiome?

Chronic refined low-fat diet consumption reduces cholecystokinin satiation in rats Abstract Purpose Reduced ability of cholecystokinin (CCK) to induce satiation contributes to hyperphagia and weight gain in high-fat/high-sucrose (HF/HS) diet-induced obesity, and has been linked to altered gut microbiota. Rodent models of obesity use chow or low-fat (LF) diets as control diets; the latter has been shown to alter gut microbiota and metabolome. We aimed to determine whether LF-diet consumption impacts CCK satiation in rats and if so, whether this is prevented by addition of inulin to LF diet. Methods Rats (n = 40) were fed, for 8 weeks, a chow diet (chow) or low-fat (10%) or high-fat/high-sucrose (45 and 17%, respectively) refined diets with either 10% cellulose (LF and HF/HS) or 10% inulin (LF-I and HF/HS-I). Caecal metabolome was assessed by 1H-NMR-based metabolomics. CCK satiation was evaluated by measuring the suppression of food intake after intraperitoneal CCK injection (1 or 3 µg/kg). Results LF-diet consumption altered the caecal metabolome, reduced caecal weight, and increased IAP activity, compared to chow. CCK-induced inhibition of food intake was abolished in LF diet-fed rats compared to chow-fed rats, while HF/HS diet-fed rats responded only to the highest CCK dose. Inulin substitution ameliorated caecal atrophy, reduced IAP activity, and modulated caecal metabolome, but did not improve CCK-induced satiety in either LF- or HF/HS-fed rats. Conclusions CCK signaling is impaired by LF-diet consumption, highlighting that caution must be taken when using LF diet until a more suitable refined control diet is identified.

Abundance of gut Prevotella at baseline and metabolic response to barley prebiotics Abstract Purpose We previously showed that short-term intervention with barley kernel bread (BKB) improved glucose tolerance. However, glucose tolerance was not improved in a subset of individuals (non-responders) who were characterized by a low Prevotella/Bacteroidesratio. The purpose of the present study was to investigate if the baseline Prevotella/Bacteroides ratio can be used to stratify metabolic responders and non-responders to barley dietary fiber (DF). Methods Fecal samples were collected from 99 healthy humans with BMI < 28 kg/m2 between 50 and 70 years old. The abundance of fecal Prevotella and Bacteroides was quantified with 16S rRNA quantitative PCR. 33 subjects were grouped in three groups: subjects with highest Prevotella/Bacteroides ratios, “HP”, n = 12; subjects with lowest Prevotella/Bacteroides ratios, “LP”, n = 13; and subjects with high abundance of both measured bacteria, HPB, n = 8. A 3-day randomized crossover intervention with BKB and white wheat bread (control) was performed. Cardiometabolic test variables were analyzed the next day following a standardized breakfast. Results The BKB intervention lowered the blood glucose responses to the breakfast independently of Prevotella/Bacteroides ratios (P < 0.01). However, independently of intervention, the HP group displayed an overall lower insulin response and lower IL-6 concentrations compared with the LP group (P < 0.05). Furthermore, the groups HP and HPB showed lower hunger sensations compared to the LP group (P < 0.05). Conclusions Here we show that the abundance of gut Prevotella and Bacteroides at baseline did not stratify metabolic responders and non-responders to barley DF intervention. However, our results indicate the importance of gut microbiota in host metabolic regulation, further suggesting that higher Prevotella/Bacteroides ratio may be favorable. ClinicalTrials.gov ID NCT02427555

Estimated dietary intake of polyphenols in European adolescents: the HELENA study Abstract Purpose Knowledge about polyphenols intakes and their determinants among adolescents might be helpful for planning targeted prevention strategies at an early age. Methods In the European multicenter cross-sectional HELENA study of 2006–2007, 2428 subjects (47% boys) had data on dietary intake of polyphenols from 2 non-consecutive 24 h recalls via linking with the Phenol-Explorer database. Differences by sex, age, country, BMI, maternal education, paternal education, family affluence, smoking status, alcohol use, and physical activity were explored by linear regression. Results Median, lower and upper quartiles of polyphenol intakes were 326, 167 and 564 mg/day, respectively. Polyphenol intake was significantly higher in the oldest (16–17.49 years), girls, non-Mediterranean countries, lowest BMI, highest paternal education, and alcohol consumers. Main food contributors were fruit (23%, mainly apple and pear, i.e., 16.3%); chocolate products (19.2%); and fruit and vegetable juices (15.6%). Main polyphenol classes were flavonoids (75–76% of total) and phenolic acids (17–19% of total). The three most consumed polyphenols were proanthocyanidin polymers (> 10 mers), hesperidin, and proanthocyanidin 4–6 oligomers. Conclusion The current study provided for the first time numbers on the total polyphenol intake and their main food sources in a heterogeneous group of European adolescents. Major differences with adult populations are the lower polyphenol consumption and the major food sources, such as chocolate and biscuits. The discussed determinants and polyphenol types already point to some important population groups that need to be targeted in future public health initiatives.

Significant metabolic improvement by a water extract of olives: animal and human evidence Abstract Purpose Dyslipidemia and impaired glucose metabolism are the main health issues of growing prevalence and significant high healthcare cost, requiring novel prevention and/or therapeutic approaches. Epidemiological and animal studies revealed that olive oil is an important dietary constituent, inducing normolipidemia. However, no studies have specifically investigated the polyphenol-rich water extract of olives (OLWPE), generated during olive oil production. Methods In the present work, we initially examined the effect of OLPWE on animals’ metabolic parameters. Rats fed with a high-fat diet were treated with three different doses of OLPWE for 4 months. Additionally, bioavailability was explored. Afterwards, OLWPE’s metabolic effect was explored in humans. Healthy volunteers consumed microencapsulated OLWPE for 4 weeks, in a food matrix [one portion (30 g) of a meat product]. Results High-fat-fed rats developed a metabolic dysfunction, with increased LDL and insulin levels and decreased HDL; this syndrome was significantly impaired when treated with OLWPE. Treated rats had increased total plasma antioxidant capacity, while several phenolic compounds were detected in their blood. These findings were also verified in humans that consumed OLWPE, daily, for 4 weeks. Interestingly, in individuals with elements of cardio-metabolic risk, OLWPE consumption resulted in reduced glucose, insulin, total cholesterol, LDL and oxLDL levels. Conclusions Our data clearly show that OLWPE can improve glucose and lipid profile, indicating its possible use in the design of functional food and/or therapeutic interventions.

Effect of diet in females (F1) from prenatally undernourished mothers on metabolism and liver function in the F2 progeny is sex-specific Abstract Purpose Poor maternal nutrition sensitises to the development of metabolic diseases and obesity in adulthood over several generations. The prevalence increases when offspring is fed with a high-fat (HF) diet after weaning. This study aims to determine whether such metabolic profiles can be transmitted to the second generation and even aggravated when the mothers were exposed to overnutrition, with attention to potential sex differences. Methods Pregnant Wistar rats were subjected to ad libitum (control) or 70% food-restricted diet (FR) during gestation (F0). At weaning, F1 females were allocated to three food protocols: (1) standard diet prior to and throughout gestation and lactation, (2) HF diet prior to and standard diet throughout gestation and lactation, and (3) HF diet prior to and throughout gestation and lactation. F2 offspring was studied between 16 and 32 weeks of age. Results FR-F2 offspring on standard diet showed normal adiposity and had no significant metabolic alterations in adulthood. Maternal HF diet resulted in sex-specific effects with metabolic disturbances more apparent in control offspring exposed to HF diet during gestation and lactation. Control offspring displayed glucose intolerance associated with insulin resistance in females. Female livers overexpressed lipogenesis genes and those of males the genes involved in lipid oxidation. Gene expression was significantly attenuated in the FR livers. Increased physical activity associated with elevated corticosterone levels was observed in FR females on standard diet and in all females from overnourished mothers. Conclusions Maternal undernutrition during gestation (F0) improves the metabolic health of second-generation offspring with more beneficial effects in females.

Association study of dietary non-enzymatic antioxidant capacity (NEAC) and colorectal cancer risk in the Spanish Multicase–Control Cancer (MCC-Spain) study Abstract Purpose Studies attempting to link dietary non-enzymatic antioxidant activity (NEAC) and colorectal cancer (CRC) risk have reported mixed results. We examined this association in the Spanish Multicase–Control Study considering the likely influence of coffee and other dietary factors. Methods 1718 CRC cases and 3312 matched-controls provided information about diet through a validated 140-item food frequency questionnaire. Dietary NEAC was estimated for three methods [total radical-trapping antioxidant parameters (TRAP), ferric reducing/antioxidant power (FRAP) and TEAC-ABTS] using published values of NEAC content in food, with and without coffee’s NEAC. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated through unconditional logistic regression models adjusted for lifestyle and dietary factors. Results Overall dietary intake of NEAC was significantly lower in cases compared to controls and associated with a significantly reduced CRC risk, in both men (ORQ5vsQ1 = 0.67, 95% CI 0.47–0.96 for FRAP) and women (ORQ5vsQ1 = 0.53, 95% CI 0.32–085 for FRAP), in multivariate models with and without the antioxidant contribution from coffee. The effect was similar for all the NEAC methods evaluated and for both colon and rectum. The association between dietary NEAC and CRC risk became non-significant when adjusting for fiber intake. However, intakes of NEAC and fiber were correlated. Conclusion This study indicates that intake of an antioxidant-rich plant-based diet, both with and without NEAC from coffee, is associated with decreased CRC risk.

High intake of dietary fibre from fruit and vegetables reduces the risk of hospitalisation for diverticular disease Abstract Backgrounds and aims High intake of dietary fibres has been associated with a reduced risk of DD. However, reports on which type of dietary fibre intake that is most beneficial have been conflicting. The aim of this study was to investigate the association between different dietary fibres and hospitalisation due to diverticular disease (DD) of the colon. Methods This was a major cohort study. The Swedish Mammography Cohort and the Cohort of Swedish Men were linked to the Swedish Inpatient Register and the Causes of Death Register. Data on the intake of dietary fibre were collected through questionnaires. The effect of intake (in quartiles) of different types of dietary fibre on the incidence of hospitalisation due to DD was investigated using multivariable Cox regression. Estimates were adjusted according to age, BMI, physical activity, co-morbidity, intake of corticosteroids, smoking, alcohol intake and education level. Results Women with intake of fruit and vegetable fibres in the highest quartile (median 12.6 g/day) had a 30% decreased risk of hospitalisation compared to those with the lowest intake (4.1 g/day). Men within the highest quartile (10.3 g/day) had a 32% decreased risk compared to those with a low intake (2.9 g/day). High intake of fibres from cereals did not affect the risk. Conclusion A high intake of fruits and vegetables may reduce the risk of hospitalisation due to DD. Intake of cereals did not influence the risk.

The insulinotropic effect of a high-protein nutrient preload is mediated by the increase of plasma amino acids in type 2 diabetes Abstract Aims Eating protein before carbohydrate reduces postprandial glucose excursions by enhancing insulin and glucagon-like peptide-1 (GLP-1) secretion in type 2 diabetes (T2D). We tested the hypothesis that this insulinotropic effect depends on the elevation of plasma amino acids (AA) after the digestion of food protein. Methods In 16 T2D patients, we measured plasma AA levels through the course of two 75-g oral glucose tolerance tests (OGTT) preceded by either 500-ml water or a high-protein nutrient preload (50-g Parmesan cheese, one boiled egg, and 300-ml water). Changes in beta cell function were evaluated by measuring and modelling plasma glucose, insulin, and C-peptide through the OGTT. Changes in incretin hormone secretion were assessed by measuring plasma GLP-1. Results Plasma AA levels were 24% higher after the nutrient preload (p < 0.0001). This increment was directly proportional to both the enhancement of beta cell function (r = 0.58, p = 0.02) and the plasma GLP-1 gradients (r = 0.57, p = 0.02) produced by the nutrient preload. Among single AA, glutamine showed the strongest correlation with changes in beta cell function (r = 0.61, p = 0.01), while leucine showed the strongest correlation with GLP-1 responses (r = 0.74, p = 0.001). Conclusions The elevation of circulating AA that occurs after a high-protein nutrient preload is associated with an enhancement of beta cell function and GLP-1 secretion in T2D. Manipulating the meal sequence of nutrient ingestion may reduce postprandial hyperglycaemia through a direct and GLP-1-mediated stimulation of insulin secretion by plasma AA. Trial registration number NCT02342834.