Alkylresorcinols (ARs) are phenolic lipids present in whole grain and bran of wheat and rye. Chemically, they comprise 1,3- dihydroxy-5-alkylbenzene homologs with odd-numbered, mainly saturated ...hydrocarbon side chains in the range of 17-25 carbon atoms. ARs are evaluated both for physiological effects and for their potential use as biomarkers of whole-grain wheat and rye intake. In this study, plasma kinetics and relative bioavailability of ARs in humans were investigated after a single intake of rye bran 120 g (190 mg ARs). The shapes of plasma concentration time curves were similar in the subjects (n = 6) with 2 peaks at ~2.8 and 6.5 h and maximum concentrations (mean ± SEM) of 1253 ± 125 and 3365 ± 309 nmol/L, respectively. The relative bioavailability of different homologs increased with increasing length of the AR side chain (r = 0.97, P < 0.001), indicating differences in metabolism. The apparent half-lives were rather short, ~5 h for all homologs, which suggests that the AR concentration in plasma could be used as a short- to medium-term biomarker of regular intake of whole-grain wheat and rye.
Metabolomics has emerged as a promising technique to understand relationships between environmental factors and health status. Through comprehensive profiling of small molecules in biological ...samples, metabolomics generates high-dimensional data objectively, reflecting exposures, endogenous responses, and health effects, thereby providing further insights into exposure-disease associations. However, the multivariate nature of metabolomics data contributes to high complexity in analysis and interpretation. Efficient visualization techniques of multivariate data that allow direct interpretation of combined exposures, metabolome, and disease risk, are currently lacking. We have therefore developed the 'triplot' tool, a novel algorithm that simultaneously integrates and displays metabolites through latent variable modeling (e.g., principal component analysis, partial least squares regression, or factor analysis), their correlations with exposures, and their associations with disease risk estimates or intermediate risk factors. This paper illustrates the framework of the 'triplot' using two synthetic datasets that explore associations between dietary intake, plasma metabolome, and incident type 2 diabetes or BMI, an intermediate risk factor for lifestyle-related diseases. Our results demonstrate advantages of triplot over conventional visualization methods in facilitating interpretation in multivariate risk modeling with high-dimensional data. Algorithms, synthetic data, and tutorials are open source and available in the R package 'triplot'.
Flavonoids are bioactive plant compounds that are widely present in the human diet. Estimating flavonoid intake with a high degree of certainty is challenging due to the inherent limitations of ...dietary questionnaires and food composition databases. This study aimed to evaluate the degree of reliability among flavonoid intakes estimated using four different approaches based on the two most comprehensive flavonoid databases, namely, United States Department of Agriculture (USDA) and Phenol Explorer (PE). In 678 individuals from the MAX study, a subcohort of the Diet, Cancer and Health-Next Generations cohort, dietary data were collected using three 24-h diet recalls over 1 year. Estimates of flavonoid intake were compared using flavonoid food content from PE as (1) aglycones (chromatography with hydrolysis), (2) aglycones transformed (converted from glycosides by chromatography without hydrolysis), (3) as they are in nature (glycosides, aglycones, and esters), and 4) using flavonoid content from USDA as aglycones (converted). Spearman's intra-class correlation (ICC) coefficient and weighted kappa (K) coefficient were calculated for the reliability analysis. When comparing PE total aglycones to USDA total aglycones, there was a moderate reliability when a continuous variable was used ICC: 0.73, 95% confidence interval (CI): 0.70-0.76 and an excellent reliability when flavonoid intake was modeled as a categorical variable (K: 0.89, 95% CI: 0.88-0.90). The degree of reliability among all methods of estimated flavonoid intakes was very similar, especially between database pairs, for the flavanol subclass, while larger differences were observed for flavone, flavonol, and isoflavone subclasses. Our findings indicate that caution should be taken when comparing the results of the associations between flavonoid intakes and health outcomes from studies, when flavonoid intakes were estimated using different methods, particularly for some subclasses.
Whole diets and dietary patterns are increasingly highlighted in modern nutrition and health research instead of single food items or nutrients alone. The Healthy Nordic Diet is a dietary pattern ...typically associated with beneficial health outcomes in observational studies, but results from randomized controlled trials are mixed. Dietary assessment is one of the greatest challenges in observational studies and compliance is a major challenge in dietary interventions. During the last decade, research has shown the great importance of the gut microbiota in health and disease. Studies have have both shown that the Nordic diet affects the gut microbiota and that the gut microbiota predicts the effects of such a diet. Rapid technique developments in the area of high-throughput mass spectrometry have enabled the large-scale use of metabolomics both as an objective measurement of dietary intake as well as in providing the final readout of the endogenous metabolic processes and the impact of the gut microbiota. In this review, we give an update on the current status on biomarkers that reflect a Healthy Nordic Diet or individual components thereof (food intake biomarkers), biomarkers that show the effects of a Healthy Nordic Diet and biomarkers reflecting the role of a Healthy Nordic Diet on the gut microbiota as well as how the gut microbiota or derived molecules may be used to predict the effects of a Healthy Nordic Diet on different outcomes.
Plant-based diets are associated with potential health benefits, but the contribution of gut microbiota remains to be clarified. We aimed to identify differences in key features of microbiome ...composition and function with relevance to metabolic health in individuals adhering to a vegan vs. omnivore diet.
This cross-sectional study involved lean, healthy vegans (
= 62) and omnivore (
= 33) subjects. We assessed their glucose and lipid metabolism and employed an integrated multi-omics approach (16S rRNA sequencing, metabolomics profiling) to compare dietary intake, metabolic health, gut microbiome, and fecal, serum, and urine metabolomes.
The vegans had more favorable glucose and lipid homeostasis profiles than the omnivores. Long-term reported adherence to a vegan diet affected only 14.8% of all detected bacterial genera in fecal microbiome. However, significant differences in vegan and omnivore metabolomes were observed. In feces, 43.3% of all identified metabolites were significantly different between the vegans and omnivores, such as amino acid fermentation products p-cresol, scatole, indole, methional (lower in the vegans), and polysaccharide fermentation product short- and medium-chain fatty acids (SCFAs, MCFAs), and their derivatives (higher in the vegans). Vegan serum metabolome differed markedly from the omnivores (55.8% of all metabolites), especially in amino acid composition, such as low BCAAs, high SCFAs (formic-, acetic-, propionic-, butyric acids), and dimethylsulfone, the latter two being potential host microbiome co-metabolites. Using a machine-learning approach, we tested the discriminative power of each dataset. Best results were obtained for serum metabolome (accuracy rate 91.6%).
While only small differences in the gut microbiota were found between the groups, their metabolic activity differed substantially. In particular, we observed a significantly different abundance of fermentation products associated with protein and carbohydrate intakes in the vegans. Vegans had significantly lower abundances of potentially harmful (such as p-cresol, lithocholic acid, BCAAs, aromatic compounds, etc.) and higher occurrence of potentially beneficial metabolites (SCFAs and their derivatives).
Sourdough fermented bread has been suggested to have beneficial health effects, in part mediated by increased satiety in the postprandial phase, but only limited research has been conducted to verify ...this. The current study aimed to investigate the effect of the amounts of sourdough and rye in soft bread on postprandial appetite. On 6 occasions, 23 healthy volunteers consumed 5 different test breads, with varying amount of rye and sourdough, and a yeast-fermented refined wheat control bread as part of a breakfast meal. The sourdough ranged between 9⁻51% of dough weight and rye content between 35⁻48% of flour weight. Appetite was recorded using visual analogue scales from immediately before breakfast and every 30 min the following 4 h. An ad libitum lunch was served 4 h after the breakfast meal, from which voluntary energy intake was measured. While some of the test breads resulted in lower hunger ratings and increased sense of fullness compared to the refined wheat bread, there were no differences between the test breads. The content of rye in the test breads differed within a narrow range, which might explain the lack of a consistent effect of rye on appetite. Microstructural examination of the test breads showed an increased aggregation of proteins in the breads with high content of sourdough, indicating additional changes to the breads, beyond change in pH, which may counteract the potential effect of decreased pH in the bread on appetite. In conclusion, our study does not support an effect of sourdough on appetite and ad libitum food intake.
High dietary fiber intake has been associated with reduced risk of
infection and co-morbidities such as gastric cancer but also with reduced risk of cardiovascular disease. It has been suggested that ...fermented rye could affect
bacterial load and that high- fiber rye may be superior to wheat for improvement of several cardiometabolic risk factors, but few long-term interventions with high fiber rye foods have been conducted.
To examine the effect of high-fiber wholegrain rye foods with added fermented rye bran vs. refined wheat on
infection and cardiometabolic risk markers in a Chinese population with a low habitual consumption of high fiber cereal foods.
A parallel dietary intervention was set up and 182 normal- or overweight men and women were randomized to consume wholegrain rye products containing fermented rye bran (FRB) or refined wheat (RW) for 12 weeks. Anthropometric measurements, fasting blood sample collection and
C-urea breath test (
C-UBT) were performed at baseline and after 6 and 12 weeks of intervention as well as 12 weeks after the end of the intervention.
No difference between diets on
bacterial load measured by
C-UBT breath test or in virulence factors of
in blood samples were found. Low density lipoprotein cholesterol (LDL-C) and high sensitivity C-reactive protein (hs-CRP) were significantly lower in the FRB group, compared to the RW group after 12 weeks of intervention. The intervention diets did not affect markers of glucose metabolism or insulin sensitivity.
While the results of the present study did not support any effect of FRB on
bacterial load, beneficial effects on LDL-C and hs-CRP were clearly shown. This suggest that consumption of high fiber rye foods instead of refined wheat could be one strategy for primary prevention of cardiovascular disease.
The trial was registered at www.clinicaltrials.gov, Identifier: NCT03103386.
Recent studies suggest that a diet rich in sugars significantly affects the gut microbiota. Adverse metabolic effects of sugars may partly be mediated by alterations of gut microbiota and gut health ...parameters, but experimental evidence is lacking. Therefore, we investigated the effects of high intake of fructose or galactose, with/without fructooligosaccharides (FOS), on gut microbiota composition in rats and explored the association between gut microbiota and low-grade systemic inflammation. Sprague–Dawley rats (
n
= 6/group) were fed the following isocaloric diets for 12 weeks (% of the dry weight of the sugars or FOS): (1) starch (control), (2) fructose (50%), (3) galactose (50%), (4) starch+FOS (15%) (FOS control), (5) fructose (50%)+FOS (15%), (6) galactose (50%)+FOS (15%), and (7) starch+olive (negative control). Microbiota composition in the large intestinal content was determined by sequencing amplicons from the 16S rRNA gene; 341F and 805R primers were used to generate amplicons from the V3 and V4 regions. Actinobacteria, Verrucomicrobia, Tenericutes, and Cyanobacteria composition differed between diets.
Bifidobacterium
was significantly higher in all diet groups where FOS was included. Modest associations between gut microbiota and metabolic factors as well as with gut permeability markers were observed, but no associations between gut microbiota and inflammation markers were observed. We found no coherent effect of galactose or fructose on gut microbiota composition. Added FOS increased Bifidobacterium but did not mitigate potential adverse metabolic effects induced by the sugars. However, gut microbiota composition was associated with several metabolic factors and gut permeability markers which warrant further investigations.
Van Trijp et al conducted a post hoc analysis of a 12-wk parallel intervention study where the effect of an intervention diet rich in whole grain wheat compared with refined wheat on markers of ...nonalcoholic fatty liver disease (NAFLD) was studied. The main study was one of the first dietary intervention trials to investigate the effect of a high whole grain compared with refined grain intake on hepatic health and markers of NAFLD. The study found increased intrahepatic triglyceride in the refined wheat group compared with the whole-grain wheat group after 12 wk of intervention, as well as a tendency toward lower C-reactive protein concentrations in the whole-grain wheat group, but contrarily also higher postprandial triglyceride in the whole-grain wheat group. Van Trijp et al only found minor alterations in gut microbiota composition following a whole-grain intervention, despite a high dose of whole grain and a long intervention period.
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