| 1. |
- Bay Nord, Anders, 1976, et al.
(författare)
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Blending Samples to Increase Accuracy and Precision of 1H NMR Urine Metabolomics
- 2024
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Ingår i: ANALYTICAL CHEMISTRY. - 0003-2700 .- 1520-6882. ; 96:32, s. 13078-13085
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Tidskriftsartikel (refereegranskat)abstract
- Urine is an equally attractive biofluid for metabolomics analysis, as it is a challenging matrix analytically. Accurate urine metabolite concentration estimates by Nuclear Magnetic Resonance (NMR) are hampered by pH and ionic strength differences between samples, resulting in large peak shift variability. Here we show that calculating the spectra of original samples from mixtures of samples using linear algebra reduces the shift problems and makes various error estimates possible. Since the use of two-dimensional (2D) NMR to confirm metabolite annotations is effectively impossible to employ on every sample of large sample sets, stabilization of metabolite peak positions increases the confidence in identifying metabolites, avoiding the pitfall of oranges-to-apples comparisons.
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| 2. |
- Karlsson, Therese, 1979, et al.
(författare)
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Identification of Single and Combined Serum Metabolites Associated with Food Intake
- 2022
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Ingår i: Metabolites. - : MDPI AG. - 2218-1989. ; 12:10
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Tidskriftsartikel (refereegranskat)abstract
- Assessment of dietary intake is challenging. Traditional methods suffer from both random and systematic errors; thus objective measures are important complements in monitoring dietary exposure. The study presented here aims to identify serum metabolites associated with reported food intake and to explore whether combinations of metabolites may improve predictive models. Fasting blood samples and a 4-day weighed food diary were collected from healthy Swedish subjects (n = 119) self-defined as having habitual vegan, vegetarian, vegetarian + fish, or omnivore diets. Serum was analyzed for metabolites by 1H-nuclear magnetic resonance spectroscopy. Associations between single and combined metabolites and 39 foods and food groups were explored. Area under the curve (AUC) was calculated for prediction models. In total, 24 foods or food groups associated with serum metabolites using the criteria of rho > 0.2, p < 0.01 and AUC ≥ 0.7 were identified. For the consumption of soybeans, citrus fruits and marmalade, nuts and almonds, green tea, red meat, poultry, total fish and shellfish, dairy, fermented dairy, cheese, eggs, and beer the final models included two or more metabolites. Our results indicate that a combination of metabolites improve the possibilities to use metabolites to identify several foods included in the current diet. Combined metabolite models should be confirmed in dose–response intervention studies.
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| 3. |
- Lindqvist, Helen, 1977, et al.
(författare)
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Validity of bioimpedance for assessment of fat-free mass in women with Rheumatoid Arthritis compared to non-rheumatic controls
- 2022
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Ingår i: Clinical Nutrition Espen. - : Elsevier BV. - 2405-4577. ; 47, s. 333-338
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Tidskriftsartikel (refereegranskat)abstract
- Background & aims: The aim was to assess the validity of bioimpedance in the assessment of fat free mass (FFM) among women and to study if the validity differs between women with and without Rheumatoid Arthritis (RA). Methods: 38 women with RA and 24 non-rheumatic controls were included. FFM was measured in the non-fasting state using DXA (Lunar Prodigy), multi-frequency bioelectrical impedance analysis (BIA) (MF-BIA [Tanita MC-180 MA]), single-frequency BIA (SF-BIA) and bioelectrical impedance spectroscopy (BIS) (both Impedimed SFB7). BIS raw data were also used to calculate FFM from equations by Matthie, Jaffrin and Moissl. Results were compared using correlation, Bland Altman analysis, Mann Whitney U test and Wilcoxon Signed Ranks Test. Results: Women with RA had different body water distribution compared to women without RA (p < 0.05). Median bias in FFM assessed by bioimpedance was 0.62-7.87 kg with wide limits of agreement for all methods. Median FFM differed significantly from DXA by all bioimpedance methods except for BIS by Jaffrin. Women with RA had significantly smaller biases compared to non-rheumatic controls using BIS equations by Matthie (p = 0.012) and Moissl (p = 0.025). Correlations between FFM measured by DXA and bioimpedance (r = 0.73-0.85, all p < 0.001) did not differ between groups. The sensitivity of bioimpedance to detect low fat free mass index (FFMI) was 0-47%. Conclusion: The results of this study show that bioimpedance has similar validity in women with RA compared to non-rheumatic controls, despite differences in body water distribution. Agreement with DXA improved when applying specific equations, but the clinical utility of bioimpedance is questionable as all methods failed to identify low FFMI with acceptable precision. (C) 2021 The Authors. Published by Elsevier Ltd on behalf of European Society for Clinical Nutrition and Metabolism.
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| 4. |
- Rådjursöga, Millie, 1977, et al.
(författare)
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Metabolic profiles from two different breakfast meals characterized by H-1 NMR-based metabolomics
- 2017
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 231, s. 267-274
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Tidskriftsartikel (refereegranskat)abstract
- It is challenging to measure dietary exposure with techniques that are both accurate and applicable to free-living individuals. We performed a cross-over intervention, with 24 healthy individuals, to capture the acute metabolic response of a cereal breakfast (CB) and an egg and ham breakfast (EHB). Fasting and postprandial urine samples were analyzed using H-1 nuclear magnetic resonance (NMR) spectroscopy and multivariate data analysis. Metabolic profiles were distinguished in relation to ingestion of either CB or EHB. Phosphocreatine/creatine and citrate were identified at higher concentrations after consumption of EHB. Beverage consumption (i.e., tea or coffee) could clearly be seen in the data. 2-furoylglycine and 5-hydroxymethyl-2-furoic acid - potential biomarkers for coffee consumption were identified at higher concentrations in coffee drinkers. Thus H-1 NMR urine metabolomics is applicable in the characterization of acute metabolic fingerprints from meal consumption and in the identification of metabolites that may serve as potential biomarkers. (C) 2017 Elsevier Ltd. All rights reserved.
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| 5. |
- Rådjursöga, Millie, 1977, et al.
(författare)
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Nutritional metabolomics: Postprandial response of meals relating to vegan, lacto-ovo vegetarian, and omnivore diets
- 2018
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Ingår i: Nutrients. - : MDPI AG. - 2072-6643. ; 10:8
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Tidskriftsartikel (refereegranskat)abstract
- Metabolomics provide an unbiased tool for exploring the modulation of the human metabolome in response to food intake. This study applied metabolomics to capture the postprandial metabolic response to breakfast meals corresponding to vegan (VE), lacto ovo-vegetarian (LOV), and omnivore (OM) diets. In a cross over design 32 healthy volunteers (16 men and 16 females) consumed breakfast meals in a randomized order during three consecutive days. Fasting and 3 h postprandial serum samples were collected and then subjected to metabolite profiling using1 H-nuclear magnetic resonance (NMR) spectroscopy. Changes in concentration of identified and discriminating metabolites, between fasting and postprandial state, were compared across meals. Betaine, choline, and creatine displayed higher concentration in the OM breakfast, while 3-hydroxyisobutyrate, carnitine, proline, and tyrosine showed an increase for the LOV and unidentified free fatty acids displayed a higher concentration after the VE breakfast. Using1 H NMR metabolomics it was possible to detect and distinguish the metabolic response of three different breakfast meals corresponding to vegan, lacto-ovo vegetarian, and omnivore diets in serum. © 2018 by the authors. Licensee MDPI, Basel, Switzerland.
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| 6. |
- Rådjursöga, Millie, 1977, et al.
(författare)
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The H-1 NMR serum metabolomics response to a two meal challenge: a cross-over dietary intervention study in healthy human volunteers
- 2019
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Ingår i: Nutrition Journal. - : Springer Science and Business Media LLC. - 1475-2891. ; 18:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Metabolomics represents a powerful tool for exploring modulation of the human metabolome in response to food intake. However, the choice of multivariate statistical approach is not always evident, especially for complex experimental designs with repeated measurements per individual. Here we have investigated the serum metabolic responses to two breakfast meals: an egg and ham based breakfast and a cereal based breakfast using three different multivariate approaches based on the Projections to Latent Structures framework. Methods: In a cross over design, 24 healthy volunteers ate the egg and ham breakfast and cereal breakfast on four occasions each. Postprandial serum samples were subjected to metabolite profiling using H-1 nuclear magnetic resonance spectroscopy and metabolites were identified using 2D nuclear magnetic resonance spectroscopy. Metabolic profiles were analyzed using Orthogonal Projections to Latent Structures with Discriminant Analysis and Effect Projections and ANOVA-decomposed Projections to Latent Structures. Results: The Orthogonal Projections to Latent Structures with Discriminant Analysis model correctly classified 92 and 90% of the samples from the cereal breakfast and egg and ham breakfast, respectively, but confounded dietary effects with inter-personal variability. Orthogonal Projections to Latent Structures with Effect Projections removed inter-personal variability and performed perfect classification between breakfasts, however at the expense of comparing means of respective breakfasts instead of all samples. ANOVA-decomposed Projections to Latent Structures managed to remove inter-personal variability and predicted 99% of all individual samples correctly. Proline, tyrosine, and N-acetylated amino acids were found in higher concentration after consumption of the cereal breakfast while creatine, methanol, and isoleucine were found in higher concentration after the egg and ham breakfast. Conclusions: Our results demonstrate that the choice of statistical method will influence the results and adequate methods need to be employed to manage sample dependency and repeated measurements in cross-over studies. In addition, H-1 nuclear magnetic resonance serum metabolomics could reproducibly characterize postprandial metabolic profiles and identify discriminatory metabolites largely reflecting dietary composition.
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