Trimethylamine-N-oxide (TMAO) is associated with various chronic diseases. TMAO is a downstream oxidative metabolite of trimethylamine (TMA) that is generated by the gut microbiota from dietary choline, carnitine, and betaine. Current analytical methods predominantly target TMAO only, due to the challenge of efficiently extracting and quantifying TMA. The present study demonstrates a simple and rapid UPLC–MRM–MS method for concurrent quantification of TMAO, TMA, and related precursors (choline, betaine, and various carnitines) following a methanol extraction from plasma and derivatization using iodoacetonitrile (IACN). Pure methanol resulted in a higher extractability of TMA (up to two-fold) compared to both pure acetonitrile and various methanol/acetonitrile mixtures. The quantification method showed high linearity within the tested range of 0.0625–100 μmol/L (determination coefficient > 0.999) and an intra- (n = 3) and inter-day (n = 9) precision of 2–8% along with an average recovery of above 94% for all metabolites (TMAO, TMA, choline, betaine, L-carnitine, acetyl-L-carnitine, and propionyl-L-carnitine). The method’s applicability was confirmed through a comparison of TMAO and its precursor concentrations in plasma samples of overnight-fasted subjects with (n = 12) and without (n = 21) metabolic syndrome.
Background/Objectives: Trimethylamine N-oxide (TMAO) is a gut microbiota-dependent metabolite considered as a risk metabolite for various non-communicable diseases. This study aims to identify differences in the gut microbiota composition and concentrations of TMAO and related metabolites in subjects with and without metabolic syndrome (MetS). Methods: Plasma samples were collected following an overnight fast on two occasions from subjects with (n = 12) and without (n = 21) MetS. Feces samples were collected on the day before the first blood sampling. The gut microbiota was profiled using 16S rRNA full-gene amplification sequencing. TMAO and related methylamines were quantified using UPLC-MSMS. The fasted plasma glucose, plasma lipid profile, and HbA1c were determined, and blood pressure, circumference, height, and weight were measured. Results: A divergent gut microbiota composition was observed in feces samples from both groups. In contrast to subjects without MetS, subjects with MetS had a reduced microbial diversity, with lower Blautia glucerasea and higher Ruminococcus torques—a pattern associated with (increased) inflammation. Trimethylamine (TMA)-producing bacteria were low in abundance across both groups. While plasma TMAO and related methylamines displayed no significant differences between both groups, L-carnitine was elevated (p = 0.0191) in subjects with MetS. A strong positive correlation was detected between TMAO and TMA (r = 0.439, p = 0.003), with a tendency to correlate with carnitine (r = 0.212, p = 0.087). Conclusions: Subjects with MetS were characterized by gut microbiota favoring inflammation-associated species but not TMA producers. This suggests that TMAO may not play a role in MetS subjects without overt comorbidities, e.g., CVD or T2D. The influence of the gut microbiota on early MetS is likely mediated through inflammatory mechanisms driven by specific bacterial shifts rather than TMAO production.
Background/Objectives: Trimethylamine N-oxide (TMAO), a gut microbiota-derived metabolite from L-carnitine and choline (abundant in meat and eggs), is linked to CVD and T2D. This study investigated whether TMAO responses to animal-based foods differ between individuals with and without metabolic syndrome (MetS), in relation to their gut microbiota composition. Subjects/Methods: In a randomized crossover trial, 12 MetS (≥3 criteria according to the Adult Treatment Panel III: elevated waist circumference, fasting glucose, triglycerides, and blood pressure or reduced HDL cholesterol) and 21 non-MetS subjects consumed two test meals (3 hard-boiled eggs or 170 g meat balls) after overnight fasting, with ≥1-week washout. Blood was collected at baseline and 0.5, 1, 2, 4, and 6 h postprandially; urine was collected over 6 h. Fecal samples (collected pre-first day of intervention) underwent 16S rRNA sequencing. Plasma and urinary TMAO, TMA, choline, and carnitine were quantified using UPLC-MS/MS. Results: MetS subjects exhibited a non-significant trend towards higher incremental AUCs for plasma TMA, TMAO, choline, and carnitine after consuming both foods, with a 30–50% higher urinary TMAO excretion (but similar for TMA) versus non-MetS subjects. This exploratory analysis also indicated that MetS subjects had reduced gut microbial diversity, featuring decreased Blautia glucerasea (butyrate producer) and increased Ruminococcus torques (pro-inflammatory), a profile associated with inflammation but not TMA production. Conclusion: No significant increase in plasma methylamines after choline and carnitine challenge was observed in subjects with MetS compared with non-MetS. In MetS subjects (without CVD and T2D), gut microbiota composition was characterized by increased pro-inflammatory bacteria rather than TMAO-generating bacteria. The lack of statistical significance with regard to plasma TMAO response could be due to an insufficient sample size rather than the absence of an effect. Nevertheless, the observed elevation might still be clinically relevant, supported by concurrent differences in microbiota composition. These preliminary findings warrant validation in larger cohorts due to sample size limitations.
Background. Food choices are influenced by habits, experiences, as well as various socioeconomic factors. Understanding these drivers can mitigate negative effects of poor nutrition and yield societal benefits. Preference elicitation methods like discrete choice experiments help understand people’s food preferences revealing factors influencing choices the most, such as nutritional content or cost of a meal. This information can be helpful in developing tailored meal-based interventions and informing food policies. Universities, as anchor institutions, are increasingly concerned with health, wellbeing, and sustainability of their students and staff. Yet, there is limited evidence on food preferences in university settings. This paper outlines a discrete choice experiment protocol to compare lunch preferences among university staff and students across six European countries, aiming to inform campus food policies. Methods. Attributes and levels were derived from a systematic literature review of preference-based studies focused on the drivers of meal choices and validated in the focus group with students and staff from participating universities. The attributes in the discrete choice experiment include nutritional content, price, time to access a meal, sensory properties of a meal, naturalness of the ingredients, and meal size. The survey was piloted in think-aloud interviews with students and staff in participating universities. We will collect preference data, along with data on participants’ sociodemographic characteristics, food-related behaviour, opinions about food, experience of food insecurity, physical activity, and body composition, using an online survey. Preference data will be analysed using random parameter logit and latent class models. Discussion. This study will be the first to investigate lunch preferences of university students and staff across six European countries, informing campus food policies. While campus food systems may not always align with students’ and staff preferences, incorporating them into policy-making can enhance satisfaction and well-being. Strengths include an international focus, inclusion of complementary variables, and involvement of potential respondents in all phases of developing this research. Acknowledging limitations, such as varying lunch habits, the study aims to provide valuable insights for improving university food policies and overall community well-being.
The health benefits of bean consumption are widely recognized and are largely attributed to the dietary fiber content. This study investigated and compared the effects of whole brown beans and an isolated bean dietary fiber fraction on the plasma lipid profile, atherosclerotic plaque amount, gut microbiota, and microbiota-dependent metabolites (cecal short-chain fatty acids (SCFAs) and plasma methylamines) in Apoe−/− mice fed high fat diets for 10.5 weeks. The results showed that both whole bean and the isolated fiber fraction had a tendency to lower atherosclerotic plaque amount, but not plasma lipid concentration. The whole bean diet led to a significantly higher diversity of gut microbiota compared with the high fat diet. Both bean diets resulted in a lower Firmicutes/Bacteroidetes ratio, higher relative abundance of unclassified S24-7, Prevotella, Bifidobacterium, and unclassified Clostridiales, and lower abundance of Lactobacillus. Both bean diets resulted in higher formation of all cecal SCFAs (higher proportion of propionic acid and lower proportion of acetic acid) and higher plasma trimethylamine N-oxide concentrations compared with the high fat diet. Whole beans and the isolated fiber fraction exerted similar positive effects on atherosclerotic plaque amount, gut microbiota, and cecal SCFAs in Apoe−/− mice compared with the control diets.
It has not been clarified whether the anti-atherosclerotic effect of lingonberry can be ascribed to its content of flavonoids or dietary fibre or both. The aim of this study was to evaluate the metabolic effects of whole lingonberries compared with isolated flavonoid and fibre fractions on atherosclerotic plaques, plasma lipid profiles, gut microbiota and microbiota-dependent metabolites in an Apoe(-/-) mouse model. Mice fed whole lingonberries showed the lowest amount of atherosclerotic plaques, while mice fed the fibre fraction had the highest formation of caecal butyric acid. Flavonoids, rather than dietary fibre, were suggested to be the components that favour proliferation of Akkermansia, as judged by the lowest abundance of this bacterium in mice fed the fibre fraction. All groups fed lingonberry diets had both, lower Firmicutes/Bacteroidetes ratios and creatinine concentrations, compared with the control. To conclude, different components in lingonberries are associated with different physiological effects in Apoe(-/-) mice.
Pulses are an important crop for the human diet. The aim of this work was to characterize phenolic compounds (flavonoids and phenolic acids) in common Swedish dried pulses and to investigate the retention and distribution of phenolic compounds during hydrothermal treatment processes, including soaking, draining, and boiling. An ultrasound-assisted extraction method was optimized for flavonoid extraction. The phenolic compounds in the raw and cooked pulses, and the processing (soaking and boiling) water were analyzed using HPLC-UV/MS. Optimized extraction conditions for flavonoids were: 70 % methanol, pH 2, and sonication for 60 min. A total of 33 flavonoids and 6 phenolic acids were directly or tentatively identified and quantified. The profile of phenolic compounds largely depends on the pulse type with the total content ranging between 38-1860 mu g/g dry matter in the raw material. In most pulses, hydrothermal treatment led to a decrease of 50-85 % of total phenolic content, mainly due to leaching. The distribution of major phenolic compound subgroups in the soaking water, boiling water, and cooked pulse varied. The rate of retention of individual phenolic compounds depends possibly on both their structure and the pulse matrix.
Yellow pea and faba bean are potential candidates to replace soybean-based ingredients due to their suitability for cultivation in the northern hemisphere, non-genetically modified organisms cultivation practice and low risk of allergenicity. This study examined the functionality of local yellow pea and faba bean protein isolates/concentrate as meat analogue products. The most critical factors affecting the texture properties of meat analogue were also determined. Extrusion was used to produce high-moisture meat analogues (HMMAs) from yellow pea and faba bean protein isolates/concentrates and HMMAs with fibrous layered structures was successfully produced from both imported commercial and local sources. The texture properties of the HMMA produced were mainly affected by the ash, fiber and protein content and water-holding capacity of the source protein. Three extrusion process parameters (target moisture content, extrusion temperature, screw speed), also significantly affected HMMA texture. In conclusion, functional HMMA can be produced using protein isolates derived from locally grown pulses.
Despite the many benefits of pulses, their consumption is still very low in many Western countries. One approach to solving this issue is to develop attractive pulse-based foods, e.g., plant-based cheeses. This study aimed to assess the suitability of different types of pulse flour, from boiled and roasted yellow peas and faba beans, to develop plant-based cheese analogues. Different stabilizer combinations (kappa- and iota-carrageenan, kappa-carrageenan, and xanthan gum) were tested. The results showed that firm and sliceable pulse-based cheese analogues could be prepared using all types of pulse flour using a flour-to-water ratio of 1:4 with the addition of 1% (w/w) kappa-carrageenan. The hardness levels of the developed pulse-based cheese analogues were higher (1883–2903 g, p < 0.01) than the reference Gouda cheese (1636 g) but lower than the commercial vegan cheese analogue (5787 g, p < 0.01). Furthermore, the crude protein (4–6% wb) and total dietary fiber (6–8% wb) contents in the developed pulse-based cheese analogues were significantly (p < 0.01) higher than in the commercial vegan cheese analogue, whereas the fat contents were lower. In conclusion, flours from boiled and roasted yellow peas and faba beans have been shown to be suitable as raw materials for developing cheese analogues with nutritional benefits.
Trimethylamine-N-oxide (TMAO), a microbiome-derived metabolite from the metabolism of choline, betaine, and carnitines, is associated to adverse cardiovascular outcomes. A method suitable for routine quantification of TMAO and its precursors (trimethylamine (TMA), choline, betaine, creatinine, and propionyl-, acetyl-, and L-carnitine) in clinical and food samples has been developed based on LC-MS. TMA was successfully derivatized using iodoacetonitrile, and no cross-reactions with TMAO or the other methylamines were detected. Extraction from clinical samples (plasma and urine) was performed after protein precipitation using acetonitrile:methanol. For food samples (meatballs and eggs), water extraction was shown to be sufficient, but acid hydrolysis was required to release bound choline before extraction. Baseline separation of the methylamines was achieved using a neutral HILIC column and a mobile phase consisting of 25 mmol/L ammonium formate in water:ACN (30:70). Quantification was performed by MS using external calibration and isotopic labelled internal standards. The assay proved suitable for both clinical and food samples and was linear from ≈ 0.1 up to 200 μmol/L for all methylamines except for TMA and TMAO, which were linear up to 100 μmol/L. Recoveries were 91-107% in clinical samples and 76-98% in food samples. The interday (n=8, four duplicate analysis) CVs were below 9% for all metabolites in clinical and food samples. The method was applied successfully to determine the methylamine concentrations in plasma and urine from the subjects participating in an intervention trial (n=10) to determine the effect of animal food ingestion on methylamine concentrations.
BACKGROUND:Legumes are nutrient-dense foods and can be an environmentally sustainable alternative to meat consumption. Data on legume intake are scarce and data on legume consumption in Sweden are lacking. This study investigated dietary intake and dietary patterns, together with iron, vitamin D, and folate status, in relation to legume consumption in Sweden.METHODS:Cross-sectional dietary and biomarker data (n 1760) from the 2011 Riksmaten national survey were analyzed. All legume foods (including soy) were identified from 4-day dietary records and ferritin, folate, and vitamin D status in a subgroup (n 280). Participants were classified into non-consumers and quartiles of legume intake. Principal Component Analysis (PCA) was performed to uncover dietary patterns associated with legume intake. Partial Least Square (PLS) regression was used to identify variables associated with variations in legume consumption.RESULTS:Legumes were consumed by 44% of the population, with mean (SD) intake of 138 (84) g/d in the highest and 11 (5) g/d in the lowest quartiles. Among consumers, 6% reported being vegetarian, compared with 0.9% among non-consumers. Legume consumers drank less alcohol, but had higher intakes of energy, dietary fiber, folate, thiamin, and several minerals, and more often met recommended intake levels for folate and fiber, critical nutrients in Sweden. Biomarker status did not differ with legume intake. PCA revealed multiple loadings on legumes that generally reflected healthier eating habits for legume-consuming women. PLS revealed that vegetarianism was most influential for high legume intake. Other influential variables were high fruit, tea, nut, and seed intakes. High intake of meat, sodas, fast foods, and sweet foods, together with omnivorism, were influential for low legume intake. The associations were similar for men and women.CONCLUSIONS:This study supports dietary recommendations on inclusion of legumes in a healthy diet. Greater focus on assessment of legume intake is necessary to explore the population-wide health effects of legumes as sustainable meat alternatives, and to reinforce national nutritional guidelines.
There is a growing demand for alternative protein-source ingredients from domestically cultivated pulses in Europe, including Sweden. However, the use of legumes as a food ingredient is limited by the presence of a distinct beany flavor. Mapping the volatile compounds composition in a standardized approach will aid in comparing different legume varieties and processing treatments. The composition of volatile compounds in flour from yellow and gray peas (raw and boiled) was investigated and compared. Volatile compounds were isolated by headspace solid-phase microextraction (HS-SPME) and analyzed using gas chromatography-mass spectrophotometry (GC-MS). A total of 43 volatiles were identified, consisting mostly of aldehydes, followed by alkanes, alcohols, ketones, alkenes, furans, terpenes, aromatics, and sulfur-containing compounds. Boiling led to a marked reduction in alcohols and an increase in aldehydes. Several markers of beany flavor, such as 1-octen-3-ol, 2-pentylfuran, and 3,5-octadien-2-one, were significantly decreased after boiling. The composition of volatiles collected from yellow and gray peas was comparable, but boiled yellow pea had a higher abundance of beany flavor as compared to gray pea. Gray pea is an interesting variety to be explored further as a potential alternative to the well-known yellow pea.
The concept of glycaemic index (GI) has led to efforts to develop low-GI foods. Bread contributes around one-quarter of carbohydrate intake in the Swedish diet. In this study, we sought to develop low-GI bread prototypes and examined the effects of bread making on content of total dietary fibre (TDF) and resistant starch (RS). Five bread prototypes were made in a commercial bakery, using sourdough fermentation and intact cereal and legume kernels. Predicted (p-GI) andin vivoGI values were determined, and TDF and RS were quantified. The p-GI value of the five prototypes was between 56 and 68. The confirmedin vivoGI value was 65 and 67 for two of the breads. The TDF content (>= 17%) was not affected by bread making, but RS content was increased by three-fold. All breads were categorised as medium-GI, but with low glycaemic load (GL).
Berries are considered an ideal source of polyphenols, especially from the flavonoid group. In this study, we examined the flavonoid content in 16 varieties of Swedish lingonberry, raspberry, blueberry, and strawberry. Nineteen flavonoids were simultaneously quantified using external standards. An additional 29 flavonoids were tentatively identified using MS as no standards were available. Quantification was done using HPLC-UV after optimization of chromatographic and extraction procedures. The method showed high linearity within the range of 2–100 μg/mL (correlation co-efficient >0.999), intra- and inter-day precision of 1.7–7.3% and average recovery above 84% for all compounds. Blueberries and lingonberries were found to contain higher contents of flavonoids (1100 mg/100 g dry weight) than raspberries and strawberries (500 mg/100 g dry weight). Anthocyanins were the dominant flavonoids in all berries. The tentatively characterized compounds contribute 18%, 29%, 61%, and 67% of the total flavonoid content in strawberries, lingonberries, raspberries, and blueberries, respectively. Overall, Swedish berries were shown to be good sources of polyphenols.
Abstract Despite the high nutritional profile in pulses, pulse consumption in Sweden is still low. However, the recent increase in consumption of sustainable and locally produced food in Sweden is driving demand for a versatile, functional pulse‐based ingredient that can be incorporated into different food products. This study assessed different treatments (boiling, roasting, and germination) when preparing flour from domestically grown pulses (yellow pea, gray pea, faba bean, and white bean). Functional properties (water and oil absorption capacity, emulsion and foaming properties, and gelation concentration) of the flours produced following different treatments and their nutrient content (total dietary fiber, total choline, and folate content) were determined. Depending on pulse type, all treatments increased (p < .001) water absorption capacity up to threefold and gelation concentration up to twofold, whereas emulsion activity and foaming capacity decreased by 3%–33% and 5%–19%, respectively, compared with flour made from raw pulses. All treatments also had a significant effect (p < .001) on nutrient content. Total dietary fiber increased (p < .02) by 11%–33%, depending on treatment and pulse type. Boiling decreased (p < .001) total choline and folate content in all pulse flours, by 17%–27% and 15%–32%, respectively. Germination doubled folate content (p < .001) in flour from both pea types compared with flour from the raw peas. In conclusion, treated pulse flours could be useful in food applications such as coating batter, dressings, beverages, or bakery goods, to improve the content of fiber, total choline, and folate.
Cereals are a good source of phenolic acids, most of which are present in bound form. The aim of this study was to develop a method for quantifying total phenolic acids in cereals that includes a robust step for hydrolysis of bound forms. Different hydrolysis procedures were evaluated. Acid hydrolysis, even with subsequent use of enzymes, proved unsuitable for releasing bound phenolic acids from the cereal matrix. Base hydrolysis (3 M, 90 min) resulted in the highest extractability, with average recoveries of 88–108% for cereal phenolic acids. The phenolic acid content in cereals (two cultivars each of rye, barley, and oats, and eight cultivars of wheat) varied up to 2-fold between cereal genotypes and 1.5-fold within genotypes. The highest content was found in rye, followed by wheat, barley, and oats. Ferulic acid dominated in all cereals, amounting to 48–72% of total phenolic acid content.
SCOPE Ingestion of rye bread leads to lower postprandial plasma insulin concentrations than wheat bread ingestion, but most often not too different glucose profiles. The mechanism behind this discrepancy is still largely unknown. This study investigates whether glucose kinetics may explain the observed discrepancy. METHODS AND RESULTS Nine healthy men participated in a crossover study, eating 50 g of available carbohydrates as either refined wheat (WB) or traditional wholemeal rye bread (WMR) during d-[6,6-2 H2 ]glucose infusion. Labeled glucose enrichment is measured by an HPLC-TOF-MS method. The calculated rate of glucose appearance (RaE) is significantly lower after ingestion of WMR during the initial 15 min postprandial period. Additionally, the 0-90 min RaE area under the curve (AUC) is significantly lower after ingestion of WMR, as is plasma gastric inhibitory polypeptide (GIP) at 60 and 90 min. Postprandial glycemic responses do not differ between the breads. Postprandial insulin is lower after ingestion of WMR at 45 and 60 min, as is the 0-90 min AUC. CONCLUSION Ingestion of WMR elicits a lower rate of glucose appearance into the bloodstream compared with WB. This may explain the lower insulin response observed after rye bread ingestion, commonly known as the rye factor.
The Western diet is characterized by high meat consumption, which negatively affects the environment and human health. Transitioning toward eating more plant-based products in Western societies has been identified as a key instrument to tackle these problems. However, one potential concern is that radically reducing meat in the current diet might lead to deficiencies in nutritional intake. In this paper, we explore a scenario in which meat consumption in Sweden is reduced by 50% and replaced by domestically grown grain legumes. We quantify and discuss the implications for nutritional intake on population level, consequences for agricultural production systems and environmental performance. The reduction in meat consumption is assumed to come primarily from a decrease in imported meat. We use data representing current Swedish conditions including the Swedish dietary survey, the Swedish food composition database, Statistics Sweden and existing life cycle assessments for different food items. At population level, average daily intake of energy and most macro- and micro-nutrients would be maintained within the Nordic Nutrition Recommendations after the proposed transition (e.g., for protein, fat, zinc, vitamin B12 and total iron). The transition would also provide a considerable increase in dietary fiber and some increase in folate intake, which are currently below the recommended levels. The transition scenario would increase total area of grain legume cultivation from 2.2% (current level) to 3.2% of Swedish arable land and is considered technically feasible. The climate impact of the average Swedish diet would be reduced by 20% and the land use requirement by 23%. There would be a net surplus of approximately 21,500 ha that could be used for bioenergy production, crop production for export, nature conservation, etc. Implementation of this scenario faces challenges, such as lack of suitable varieties for varying conditions, lack of processing facilities to supply functional legume-based ingredients to food industries and low consumer awareness about the benefits of eating grain legumes. In sum, joint efforts from multiple actors are needed to stimulate a decrease in meat consumption and to increase cultivation and use of domestically grown grain legumes.
Public health authorities recommend all fertile women to increase their folate intake to 400 mu g/d by eating folate-rich foods or by taking a folic acid supplement to protect against neural tube defects. In a previous study it was shown that folate-rich foods improved folate blood status as effectively as folic acid supplementation. The aim of the present study was to investigate, using NMR metabolomics, the effects of an intervention with a synthetic folic acid supplement v. native food folate on the profile of plasma metabolites. Healthy women with normal folate status received, in parallel, 500 mu g/d synthetic folic acid from a supplement (n 18), 250 mu g/d folate from intervention foods (n 19), or no additional folate (0 mu g/d) through a portion of apple juice (n 20). The metabolic profile of plasma was measured using H-1-NMR in fasted blood drawn at baseline and after 12 weeks of intervention. Metabolic differences between the groups at baseline and after intervention were assessed using a univariate statistical approach (P <= 0.001, Bonferroni-adjusted significance level). At baseline, the groups showed no significant differences in measured metabolite concentrations. After intervention, eight metabolites, of which six (glycine, choline, betaine, formate, histidine and threonine) are related to one-carbon metabolism, were identified as discriminative metabolites. The present study suggests that different folate forms (synthetic v. natural) may affect related one-carbon metabolites differently.