Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Root traits and belowground herbivores relate toplant–soil feedback variation among congeners
Wilschut, Rutger ; Putten, W.H. van der; Garbeva, Paolina ; Harkes, Paula ; Konings, W. ; Kulkarni, Purva ; Martens, H.J. ; Geisen, Stefan - \ 2019
Nature Communications 10 (2019). - ISSN 2041-1723
Plant–soil feedbacks contribute to vegetation dynamics by species-specific interactionsbetween plants and soil biota. Variation in plant–soil feedbacks can be predicted by roottraits, successional position, and plant nativeness. However, it is unknown whether closelyrelated plant species develop more similar plant–soil feedbacks than more distantly relatedspecies. Where previous comparisons included plant species from distant phylogeneticpositions, we studied plant–soil feedbacks of congeneric species. Using eight intra-continentally range-expanding and nativeGeraniumspecies, we tested relations betweenphylogenetic distances, chemical and structural root traits, root microbiomes, and plant–soilfeedbacks. We show that root chemistry and specific root length better predict bacterial andfungal community composition than phylogenetic distance. Negative plant–soil feedbackstrength correlates with root-feeding nematode numbers, whereas microbiome dissimilarity,nativeness, or phylogeny does not predict plant–soil feedbacks. We conclude that rootmicrobiome variation among congeners is best explained by root traits, and that root-feedingnematode abundances predict plant–soil feedbacks.
Wageningen hunkert naar Eindhovense kennis
Nierop Groot, Masja ; Mol, Arthur ; Hemming, Silke - \ 2018

Wetenschappers van de universiteit van Wageningen (WUR) en van de TU/e vinden elkaar op dit moment ook al op verschillende onderzoeksterreinen, maar de bestuurders van beide instellingen denken dat er nog veel meer mogelijk is. De komende jaren willen ze de onderlinge samenwerking stevig gaan versterken en hopen daarmee dat de mensen op de werkvloer elkaar nog vaker weten te vinden. "Want die spreken dezelfde taal."

The effects of feedstock polydispersity on conversion kinetics: modelling starch oxidation
Hoogstad, Tim ; Konings, G. ; Boxtel, A.J.B. van; Buwalda, P.L. ; Bitter, J.H. - \ 2018
Intermodality and synchromodality
Tavasszy, L. ; Behdani, B. ; Konings, Rob - \ 2018
In: Ports and Networks - Strategies, Operations and Perspectives / Geerlings, Harry, Kuipers, Bart, Zuidwijk, Rob, Oxon : Routledge - ISBN 9781472485007 - p. 251 - 266.
Transport networks have evolved from multimodal networks towards integrated networks allowing for intermodal transport – the carriage of a single load unit by consecutive modes in a transport chain. Synchromodality (or synchronized intermodality) – as the next stage in port/hinterland network development – can be briefly summarized as the vision of a network of well-synchronized and interconnected transport modes, which together cater for the aggregate transport demand and can dynamically adapt to the individual and instantaneous needs of network users. The objective of the chapter is to introduce the idea of Synchromodality. We discuss the current position and evolution of intermodal hinterland transport systems. Next, we describe the main elements of a synchronized intermodal transport system and the innovations that are necessary to arrive at synchromodal transport systems. We further describe the barriers for future development including technological, economical and institutional aspects.
How People Domesticated Amazonian Forests
Levis, C. ; Flores, Bernardo ; Moreira, Priscilla ; Luize, Bruno G. ; Alves, Rubana ; Franco-Moraes, Juliano ; Lins, Juliana ; Konings, Evelien ; Pena Claros, M. ; Bongers, F. ; Costa, Flavia ; Clement, Charles - \ 2018
Frontiers in Ecology and Evolution 5 (2018). - ISSN 2296-701X - 21 p.
For millennia, Amazonian peoples have managed forest resources, modifying the natural environment in subtle and persistent ways. Legacies of past human occupation are striking near archaeological sites, yet we still lack a clear picture of how human management practices resulted in the domestication of Amazonian forests. The general view is that domesticated forests are recognizable by the presence of forest patches dominated by one or a few useful species favored by long-term human activities. Here, we used three complementary approaches to understand the long-term domestication of Amazonian forests. First, we compiled information from the literature about how indigenous and traditional Amazonian peoples manage forest resources to promote useful plant species that are mainly used as food resources. Then, we developed an interdisciplinary conceptual model of how interactions between these management practices across space and time may form domesticated forests. Finally, we collected field data from 30 contemporary villages located on and near archaeological sites, along four major Amazonian rivers, to compare with the management practices synthesized in our conceptual model. We identified eight distinct categories of management practices that contribute to form forest patches of useful plants: (1) removal of non-useful plants, (2) protection of useful plants, (3) attraction of non-human animal dispersers, (4) transportation of useful plants, (5) selection of phenotypes, (6) fire management, (7) planting of useful plants, and (8) soil improvement. Our conceptual model, when ethnographically projected into the past, reveals how the interaction of these multiple management practices interferes with natural ecological processes, resulting in the domestication of Amazonian forest patches dominated by useful species. Our model suggests that management practices became more frequent as human population increased during the Holocene. In the field, we found that useful perennial plants occur in multi-species patches around archaeological sites, and that the dominant species are still managed by local people, suggesting long-term persistence of ancient cultural practices. The management practices we identified have transformed plant species abundance and floristic composition through the creation of diverse forest patches rich in edible perennial plants that enhanced food production and food security in Amazonia.
Effects of plant stanol ester consumption on fasting plasma oxy(phyto)sterol concentrations as related to fecal microbiota characteristics
Baumgartner, Sabine ; Mensink, Ronald P. ; Smet, Els De; Konings, Maurice ; Fuentes Enriquez de Salamanca, Susana ; Vos, Willem M. de; Plat, Jogchum - \ 2017
Journal of Steroid Biochemistry and Molecular Biology 169 (2017). - ISSN 0960-0760 - p. 46 - 53.
Gut microbiota - Oxycholesterols - Oxyphytosterols - Plant stanols
Information regarding dietary effects on plasma oxyphytosterol concentrations as well as on the origin of oxyphytosterols is scarce. We hypothesized that plant sterols are oxidized in the intestinal lumen, mediated by microbial activity, followed by uptake into the circulation. To address this hypothesis, we carried out, a randomized, double blind, crossover study in 13 healthy subjects, who consumed for 3 weeks control and plant stanol ester enriched margarines (3.0. g/d plant stanols) separated by a 4-week wash-out period. Plasma oxy(phyto)sterols were determined via GC-MS/MS, while microbiota analyses were performed on fecal DNA using a phylogenetic microarray to assess microbial composition and diversity. Plasma plant sterol concentrations did not correlate with plasma oxyphytosterols concentrations at baseline. Plant stanol consumption reduced serum sitosterol and campesterol concentrations (-37% and -38%), respectively (p
Sodium fluoroacetate ("Compound 1080") in infant formula
Sullivan, Darryl ; Alewijn, Martin ; Austad, John ; Boison, Joe ; Christiansen, Scott ; Cook, Jo Marie ; Vries, Jon De; Indyk, Harvey ; Joseph, George ; Konings, Erik ; Krynitsky, Alex ; Phillips, Tom ; Popping, Bert ; Reddy, Murali ; Wong, John ; Coates, Scott - \ 2015
Journal of AOAC International 98 (2015)4. - ISSN 1060-3271 - p. 1092 - 1093.

Determination of total fluoroacetic acid and its salts in all forms of infant formula is evaluated. Infant formula includes breast-milk substitute specially manufactured to satisfy, by itself, the nutritional requirements of infants during the first months of life up to the introduction of appropriate complementary feeding, made from any combination of milk, soy, rice, whey, hydrolyzed protein, starch, and amino acids, with and without intact protein. Suitable methods will include blank check samples, and check standards at the lowest point and midrange point of the analytical range.

Determination of sodium monofluoroacetate in dairy powders by liquid chromatography tandem mass spectrometry (LC-MS/MS): First Action 2015.02
Joseph, George ; Sullivan, Darryl ; Alewijn, Martin ; Austad, John ; Boison, Joe ; Christiansen, Scott ; Cook, Jo Marie ; Vries, Jon De; Indyk, Harvey ; Konings, Erik ; Krynitsky, Alex ; Phillips, Tom ; Popping, Bert ; Reddy, Murali ; Wong, John - \ 2015
Journal of AOAC International 98 (2015)4. - ISSN 1060-3271 - p. 1121 - 1126.

Determination of sodium monofluoroacetate in dairy powders by liquid chromatography tandem mass spectrometry (LC-MS/MS) is discussed. Samples are dissolved in water and extracted into acetone to allow precipitation of proteins. After centrifugation, the solutions are passed through an anion exchange column and eluted with acid to give free fluoroacetic acid. This acid is converted to 2-fluoro-3?-nitroacetanilide via a carbodiimide-mediated amide coupling reaction. The derivative is then subjected to SPE cleanup, eluting with t-butyl methyl ether (TBME)?n-hexane, concentrated and quantified by LC-MS/MS using derivatized isotopically substituted sodium fluoroacetate as an internal standard.

Determination of monofluoroacetate in powdered nutritional products by derivatization with 2-nitrophenylhydrazine and LC-MS/MS: First action 2015.04
Reddy, Murali ; Sullivan, Darryl ; Alewijn, Martin ; Austad, John ; Boison, Joe ; Christiansen, Scott ; Cook, Jo Marie ; Vries, Jon De; Indyk, Harvey ; Joseph, George ; Konings, Erik ; Krynitsky, Alex ; Phillips, Tom ; Popping, Bert ; Wong, John - \ 2015
Journal of AOAC International 98 (2015)4. - ISSN 1060-3271 - p. 1135 - 1139.

Determination of monofluoroacetate in powdered nutritional products by derivatization with 2-nitrophenylhydrazine and LC-MS/MS IS discussed. Samples are prepared by dilution in water followed by protein precipitation with acetonitrile. An aliquot of the sample extract is derivatized with 2-nitrophenylhydrazine (2-NPH) in the presence of 1-ethyl-3-(-3-dimethylaminopropyl) carbodiimide hydrochloride (EDC). This reaction achieves the coupling of the carboxyl group of monofluoroacetate to the amino group of 2-NPH with the formation of an amide bond. Samples are processed through a solid-phase extraction (SPE) step in order to exchange.

Determination of sodium fluoroacetate in infant formula by liquid chromatography-tandem mass spectrometry (LC-MS/MS): First Action 2015.03
Mottier, Pascal ; Sullivan, Darryl ; Alewijn, Martin ; Austad, John ; Boison, Joe ; Christiansen, Scott ; Cook, Jo Marie ; Vries, Jon De; Indyk, Harvey ; Joseph, George ; Konings, Erik ; Krynitsky, Alex ; Phillips, Tom ; Popping, Bert ; Reddy, Murali ; Wong, John - \ 2015
Journal of AOAC International 98 (2015)4. - ISSN 1060-3271 - p. 1127 - 1134.

Determination of sodium fluoroacetate in infant formula by liquid chromatography-tandem mass spectrometry (LC-MS/MS)is discussed. Sodium fluoroacetate is also a naturally occurring poison found in at least 40 plants native in Australia, South and West Africa, and Brazil. Milk powder is first reconstituted in water. Liquid sample is used as such. Acetonitrile is added to precipitate proteins. After centrifugation, the supernatant is washed with hexane and then acidified with concentrated sulfuric acid. QuEChERS salts are added for phase separation and the mixture is centrifuged. The resulting supernatant is evaporated to 0.5 mL remaining volume and centrifuged before LC-MS/MS analysis in selected reaction monitoring (SRM) by electrospray ionization (ESI) in negative mode.

The effects of 30 days resveratrol supplementation on adipose tissue morphology and gene expression patterns in obese men
Konings, E. ; Timmers, S. ; Boekschoten, M.V. ; Goossens, G.H. ; Jocken, J.W. ; Afman, L.A. ; Müller, M.R. ; Schrauwen, P. ; Mariman, E.C. ; Blaak, E.E. - \ 2014
International Journal of Obesity 38 (2014)3. - ISSN 0307-0565 - p. 470 - 473.
insulin-resistance - glucose-tolerance - adipogenesis - metabolism - health - women - mice
Polyphenolic compounds, such as resveratrol, have recently received widespread interest because of their ability to mimic effects of calorie restriction. The objective of the present study was to gain more insight into the effects of 30 days resveratrol supplementation on adipose tissue morphology and underlying processes. Eleven healthy obese men were supplemented with placebo and resveratrol for 30 days (150¿mg per day), separated by a 4-week washout period in a double-blind randomized crossover design. A postprandial abdominal subcutaneous adipose tissue biopsy was collected to assess adipose tissue morphology and gene expression using microarray analysis. Resveratrol significantly decreased adipocyte size, with a shift toward a reduction in the proportion of large and very-large adipocytes and an increase in small adipocytes. Microarray analysis revealed downregulation of Wnt and Notch signaling pathways and upregulation of pathways involved in cell cycle regulation after resveratrol supplementation, suggesting enhanced adipogenesis. Furthermore, lysosomal/phagosomal pathway and transcription factor EB were upregulated reflecting an alternative pathway of lipid breakdown by autophagy. Further research is necessary to investigate whether resveratrol improves adipose tissue function.
Effects of 30 days resveratrol supplementation on adipose tissue morphology and gene expression patterns in obese men
Konings, E. ; Timmers, S. ; Boekschoten, Mark ; Goossens, G.H. ; Jocken, J.W. ; Afman, Lydia ; Muller, Michael ; Schrauwen, P. ; Mariman, E.C. ; Blaak, E.E. - \ 2013
GSE42432 - Homo sapiens - PRJNA181956
Polyphenolic compounds, such as resveratrol, have recently received widespread interest due to their ability to mimic effects of calorie restriction. The objective of the present study was to gain more insight into the effects of 30 days resveratrol supplementation on adipose tissue morphology and underlying processes. Nine healthy obese men were supplemented with placebo and 150mg/day resveratrol for 30 days, separated by a 4-week washout period. A postprandial abdominal subcutaneous adipose tissue biopsy was collected to assess adipose tissue morphology and gene expression using microarray analysis. Resveratrol significantly decreased adipocyte size, with a shift towards a reduction in the proportion of large and very large adipocytes and an increase in small adipocytes. Microarray analysis revealed downregulation of Wnt, Notch and BMP/TGF-β signaling pathways and upregulation of pathways involved in cell cycle after resveratrol supplementation, suggesting enhanced adipogenesis. Furthermore, the lysosomal/phagosomal pathway and the transcription factor EB were upregulated, reflecting an alternative pathway of lipid breakdown by autophagy. These data suggest that adipose tissue is an important target tissue for the effects of resveratrol in humans, but further research is necessary to investigate whether it translates into an improved adipose tissue function.
Polyunsaturated fatty acids acutely affect triacylglycerol-derived skeletal muscle fatty acid uptake and increases postprandial insulin sensitivity
Jans, Anneke ; Konings, Ellen ; Goossens, Gijs H. ; Bouwman, Freek G. ; Moors, Chantalle C. ; Boekschoten, Mark ; Afman, Lydia ; Muller, Michael ; Mariman, Edwin C. ; Blaak, Ellen E. - \ 2012
GSE31901 - Homo sapiens - PRJNA145213
Dietary fat quality may influence skeletal muscle lipid handling and fat accumulation, thereby modulating insulin sensitivity. Objective: To examine acute effects of meals with various fatty acid (FA) compositions on skeletal muscle FA handling and postprandial insulin sensitivity in obese insulin resistant men. Design: In a single-blinded randomized crossover study, 10 insulin resistant men consumed three high-fat mixed-meals (2.6MJ). Meals were high in saturated FA (SFA), in monounsaturated FA (MUFA) or in polyunsaturated FA (PUFA). Fasting and postprandial skeletal muscle FA handling were examined by measuring arterio-venous concentration differences across forearm muscle. [2H2]-palmitate was infused intravenously to label endogenous triacylglycerol (TAG) and FFA in the circulation and [U-13C]-palmitate was added to the meal to label chylomicron-TAG. Skeletal muscle biopsies were taken to assess intramuscular lipid metabolism and gene expression. Results: Insulin and glucose responses (AUC) after SFA meal were significantly higher compared with PUFA meal (p=0.003 and 0.028, respectively). Uptake of TAG-derived FA was significantly lower in the early postprandial phase after PUFA meal as compared with other meals (AUC60-120, p<0.001). The PUFA meal induced less transcriptional downregulation of oxidative pathways compared with other meals. The fractional synthetic rate was higher in DAG and PL fraction after MUFA and PUFA meal. Conclusion: Intake of a PUFA meal reduced TAG-derived skeletal muscle FA uptake, which was accompanied by higher postprandial insulin sensitivity and a tendency towards a higher muscle lipid turnover. These data suggest that the effects of replacement of SFA by PUFA may contribute to less muscle lipid uptake and may be therefore protective against the development of insulin resistance.
Intestinally secreted C-type lectin Reg3b attenuates salmonellosis but not listeriosis in mice
Ampting, M.T.J. van; Loonen, L.M.P. ; Schonewille, A.J. ; Konings, I. ; Vink, C. ; Iovanna, J. ; Chamaillard, M. ; Dekker, J. ; Meer, R. van der; Wells, J. ; Bovee-Oudenhoven, I.M.J. - \ 2012
Infection and Immunity 80 (2012)3. - ISSN 0019-9567 - p. 1115 - 1120.
bactericidal lectin - host-cells - expression - gut - infection - entry - rats - monocytogenes - mechanisms - induction
The Reg3 protein family, including the human member designated pancreatitis-associated protein (PAP), consists of secreted proteins that contain a C-type lectin domain involved in carbohydrate binding. They are expressed by intestinal epithelial cells. Colonization of germ-free mice and intestinal infection with pathogens increase the expression of Reg3g and Reg3b in the murine ileum. Reg3g is directly bactericidal for Gram-positive bacteria, but the exact role of Reg3b in bacterial infections is unknown. To investigate the possible protective role of Reg3b in intestinal infection, Reg3b knockout (Reg3b-/-) mice and wild-type (WT) mice were orally infected with Gram-negative Salmonella enteritidis or Gram-positive Listeria monocytogenes. At day 2 after oral Listeria infection and at day 4 after oral Salmonella infection, mice were sacrificed to collect intestinal and other tissues for pathogen quantification. Protein expression of Reg3b and Reg3g was determined in intestinal mucosal scrapings of infected and noninfected mice. In addition, ex vivo binding of ileal mucosal Reg3b to Listeria and Salmonella was investigated. Whereas recovery of Salmonella or Listeria from feces of Reg3b-/- mice did not differ from that from feces of WT mice, significantly higher numbers of viable Salmonella, but not Listeria, bacteria were recovered from the colon, mesenteric lymph nodes, spleen, and liver of the Reg3b-/- mice than from those of WT mice. Mucosal Reg3b binds to both bacterial pathogens and may interfere with their mode of action. Reg3b plays a protective role against intestinal translocation of the Gram-negative bacterium S. enteritidis in mice but not against the Gram-positive bacterium L. monocytogenes.
PUFAs acutely affect triacylglycerol-derived skeletal muscle fatty acid uptake and increase postprandial insulin sensitivity
Jans, A. ; Konings, E. ; Goossens, G.H. ; Bouwman, F.G. ; Moors, C.C. ; Boekschoten, M.V. ; Afman, L.A. ; Muller, M.R. ; Mariman, E.C. ; Blaak, E.E. - \ 2012
American Journal of Clinical Nutrition 95 (2012). - ISSN 0002-9165 - p. 825 - 836.
beta-cell function - olive oil - metabolic syndrome - adipose-tissue - resistant subjects - glucose-tolerance - gene-expression - protein-content - soybean-oil - obesity
Background: Dietary fat quality may influence skeletal muscle lipid processing and fat accumulation, thereby modulating insulin sensitivity. Objective: The objective was to examine the acute effects of meals with various fatty acid (FA) compositions on skeletal muscle FA processing and postprandial insulin sensitivity in obese, insulin-resistant men. Design: In a single-blind, randomized, crossover study, 10 insulin-resistant men consumed 3 high-fat mixed meals (2.6 MJ), which were high in SFAs, MUFAs, or PUFAs. Fasting and postprandial skeletal muscle FA processing was examined by measuring differences in arteriovenous concentrations across the forearm muscle. [H-2(2)]Palmitate was infused intravenously to label endogenous triacylglycerol and FFAs in the circulation, and [U-C-13]palmitate was added to the meal to label chylomicron-triacylglycerol. Skeletal muscle biopsy samples were taken to assess intramuscular lipid metabolism and gene expression. Results: Insulin and glucose responses (AUC) after the SFA meal were significantly higher than those after the PUFA meal (P = 0.006 and 0.033, respectively). Uptake of triacylglycerol-derived FAs was lower in the postprandial phase after the PUFA meal than after the other meals (AUC(60-240); P = 0.02). The fractional synthetic rate of the triacylglycerol, diacylglycerol, and phospholipid pool was higher after the MUFA meal than after the SFA meal. PUFA induced less transcriptional downregulation of oxidative pathways than did the other meals. Conclusion: PUFAs reduced triacylglycerol-derived skeletal muscle FA uptake, which was accompanied by higher postprandial insulin sensitivity, a more transcriptional oxidative phenotype, and altered intra-myocellular lipid partitioning and may therefore be protective against the development of insulin resistance. This trial was registered at clinicaltrials.gov as NCT01466816. Am J Clin Nutr 2012;95:825-36.
Calorie restriction-like effects of 30 days of resveratrol supplementation on energy metabolism and metabolic profile in obese humans
Timmers, Silvie ; Konings, Ellen ; Bilet, Lena ; Houtkooper, Riekelt H. ; Weijer, Tineke van de; Hoeks, Joris ; Krieken, Sophie van der; Ryu, Dongryeol ; Kersten, Sander ; Moonen-Kornips, Esther ; Goossens, Gijs H. ; Hesselink, Matthijs K. ; Kunz, Iris ; Schrauwen-Hinderling, Vera B. ; Blaak, Ellen E. ; Auwerx, Johan ; Schrauwen, Patrick - \ 2011
Homo sapiens - GSE32357 - PRJNA14724
Resveratrol is a naturally occurring compound that profoundly affects energy metabolism and mitochondrial function and serves as a calorie restriction mimetic, at least in animal models of obesity. Here we treated 10 healthy, obese men with placebo and 150 mg/day resveratrol in a randomized double-blind cross-over study for 30 days. Resveratrol supplementation significantly reduced sleeping- and resting metabolic rate. In muscle, resveratrol activated AMPK, increased SIRT1 and PGC-1alpha protein levels, increased citrate synthase activity, and improved muscle mitochondrial respiration on a fatty acid-derived substrate. Furthermore, resveratrol elevated intramyocellular lipid levels, and decreased intrahepatic lipid content, circulating glucose, triglycerides, alanine-aminotransferase, and inflammation markers. Systolic blood pressure dropped and HOMA index improved after resveratrol. In the postprandial state, adipose tissue lipolysis and plasma fatty acid and glycerol decreased. In conclusion, we demonstrate that 30 days of resveratrol supplementation induces profound metabolic changes in obese subjects, mimicking the effects of calorie restriction.
Calorie Restriction-like Effects of 30 Days of Resveratrol Supplementation on Energy Metabolism and Metabolic Profile in Obese Humans
Timmers, S. ; Konings, E. ; Bilet, L. ; Houtkooper, R.H. ; Weijer, T. van de; Goossens, G.H. ; Hoeks, J. ; Krieken, S. van der; Ryu, D. ; Kersten, A.H. ; Moonen-Kornips, E. ; Hesselink, M.K.C. ; Kunz, I. ; Schrauwen-Hinderling, V.B. ; Blaak, E.E. ; Auwerx, J. ; Schrauwen, P. - \ 2011
Cell Metabolism 14 (2011)5. - ISSN 1550-4131 - p. 612 - 622.
beta-cell function - life-span - insulin sensitivity - mitochondrial-function - skeletal-muscle - saccharomyces-cerevisiae - sirt1 activation - lipid-metabolism - fat oxidation - exercise
Resveratrol is a natural compound that affects energy metabolism and mitochondrial function and serves as a calorie restriction mimetic, at least in animal models of obesity. Here, we treated 11 healthy, obese men with placebo and 150 mg/day resveratrol (resVida) in a randomized double-blind crossover study for 30 days. Resveratrol significantly reduced sleeping and resting metabolic rate. In muscle, resveratrol activated AMPK, increased SIRT1 and PGC-1 alpha protein levels, increased citrate synthase activity without change in mitochondrial content, and improved muscle mitochondrial respiration on a fatty acid-derived substrate. Furthermore, resveratrol elevated intramyocellular lipid levels and decreased intrahepatic lipid content, circulating glucose, triglycerides, alanine-aminotransferase, and inflammation markers. Systolic blood pressure dropped and HOMA index improved after resveratrol. In the postprandial state, adipose tissue lipolysis and plasma fatty acid and glycerol decreased. In conclusion, we demonstrate that 30 days of resveratrol supplementation induces metabolic changes in obese humans, mimicking the effects of calorie restriction.
Monitoring of polycyclic aromatic hydrocarbons (PAH) in food supplements containing botanicals and other ingredients on the Dutch market
Martena, M.J. ; Grutters, M. ; Groot, H.N. de; Konings, E.J.M. ; Rietjens, I. - \ 2011
Food Additives & Contaminants. Pt. A, Chemistry, Analysis, Control, Exposure & Risk Assessment 28 (2011)7. - ISSN 1944-0049 - p. 925 - 942.
performance liquid-chromatography - fluorescence detection
Food supplements can contain polycyclic aromatic hydrocarbons (PAH). The European Food Safety Authority (EFSA) has defined 16 priority PAH that are both genotoxic and carcinogenic and identified eight priority PAH (PAH8) or four of these (PAH4) as good indicators of the toxicity and occurrence of PAH in food. The current study aimed to determine benzo[a]pyrene and other EFSA priority PAH in different categories of food supplements containing botanicals and other ingredients. From 2003 to 2008, benzo[a]pyrene exceeded the limit of quantification (LOQ) in 553 (44%) of 1258 supplements with a lower-bound mean of 3.37¿µg¿kg-1. In 2008 and 2009, benzo[a]pyrene and 12 other EFSA priority PAH were determined in 333 food supplements. Benzo[a]pyrene exceeded the LOQ in 210 (63%) food supplements with a lower-bound mean of 5.26¿µg¿kg-1. Lower-bound mean levels for PAH4 and PAH8(-indeno[1,2,3-cd]pyrene) were 33.5 and 40.5¿µg¿kg-1, respectively. Supplements containing resveratrol, Ginkgo biloba, St. John's wort and propolis showed relatively high PAH4 levels in 2008 and 2009. Before 2008, supplements with these ingredients and also dong quai, green tea or valerian contained relatively high benzo[a]pyrene levels. On average, PAH4 intake resulting from food supplement use will be at the lower end of the range of contributions of main food groups to PAH4 exposure, although individual food supplements can contribute significantly to PAH4 exposure. Regular control of EFSA indicator PAH levels in food supplements may prove a way forward to reduce further the intake of PAH from food.
Food Fermentations
Smid, E.J. ; Wood, B.J.B. - \ 2011
In: Thirty Years of Research on Lactic Acid Bacteria : celebrating the 10th Symposium on LAB / Ledeboer, A., Hugenholtz, J., Kok, J., Konings, W., Wouters, J., Rotterdam, The Netherlands : 24 Media LABS - ISBN 9789081767101 - p. 171 - 183.
Safety of herbal preparations on the Dutch market
Martena, M.J. - \ 2010
Wageningen University. Promotor(en): Ivonne Rietjens, co-promotor(en): E.J.M. Konings. - [S.l.] : S.n. - ISBN 9789085858225 - 224
keukenkruiden - azië - voedingsmiddelenwetgeving - toxiciteit - besmetters - analyse - natuurlijke toxinen - culinary herbs - asia - food legislation - toxicity - contaminants - analysis - natural toxins
The use and availability of herbal preparations covered by food law is increasing in the Netherlands and in other European Member States. Correspondingly, safety concerns relating to herbal preparations are growing as well. The aim of the present PhD project was therefore to review the toxicity of selected herbal preparations, to investigate the presence and actual levels of selected naturally-occurring toxic substances and contaminants in herbal preparations on the Dutch market and to estimate the associated risks.
First, an overview is provided of the Dutch and European legal provisions for food commodities with botanical ingredients, the nature and mechanism of action of various toxic botanical ingredients specifically covered by these provisions, and the health concerns defined by risk assessors related to several botanicals for which no specific legal provisions exist. Secondly, data are presented on the actual occurrence in traditional herbal preparations (THPs) of a group of phytotoxins, i.e. aristolochic acids, which were banned by the Dutch Commodities Act Decree ‘Herbal preparations’. Aristolochic acids and derivatives are nephrotoxic, genotoxic and carcinogenic and are present in several plants from the Aristolochiaceae family. Aristolochic acids were found in 25 of 190 THPs used in Traditional Chinese Medicine (TCM) sampled on the Dutch market. This shows that testing for aristolochic acids of Chinese THPs at risk of contamination is essential in the framework of food safety.
Thirdly, the presence of selected toxic contaminants in herbal preparations on the Dutch market was investigated. Lead, mercury and arsenic levels were analyzed in THPs used in several Asian traditional medicine systems, such as Ayurveda, TCM, and Traditional Tibetan Medicine (TTM). These metals and metalloids were present in 186 (64%) of 292 THPs and use at recommended dose levels of 59 THPs (20%) would result in intakes of these contaminants significantly above established toxicological safety limits. It was concluded that the mercury, arsenic and lead contents of these Asian THPs are cause for concern. Because metals such as mercury can exist in various defined chemical species with different toxic properties, a study was performed using selective acid extraction procedures to determine the presence or absence of the relatively non-toxic elemental form of mercury in 19 Ayurvedic THPs, which were shown in the previous study to result in mercury intakes above the safety limit for inorganic mercury when used at the recommended daily dose level. It was concluded that in these THPs the main part of the mercury content is not present in the elemental form, that the mercury detected in Ayurvedic THPs is likely to be present in the inorganic form and that therefore the estimation of the related risks based on the safety limits for inorganic mercury is justified.
In the last study of this PhD thesis, polycyclic aromatic hydrocarbons (PAH) were determined in more than 1500 food supplements sampled on the Dutch market, many of which contained herbal ingredients. Herbal preparations can become contaminated with PAH through various processes including direct atmospheric deposition on plant surfaces and drying practices during manufacturing. Several PAH, such as benzo[a]pyrene are genotoxic and carcinogenic. Supplements containing herbal ingredients such as St. John’s wort and Ginkgo biloba, the phytochemical resveratrol and the bee product propolis showed the highest mean PAH levels. It was shown that individual food supplements can contribute significantly to PAH exposure, whereas on average PAH intake resulting from food supplement use will be at the lower end of the range of contributions of main food groups to PAH exposure.
From the work described in this thesis it can be concluded that for herbal preparations ‘natural’ does not equal ‘safe’. Given that uncertainty exists whether additional European legal measures will be taken in the near future to restrict or prohibit the use of specific toxic herbal substances in foods and the fact that several herbal preparations for which specific provisions are absent in Dutch food safety law raise toxicological concern, would suggest that it is prudent to keep the Dutch Decree ‘Herbal preparations’ and other national legislation up to date in order to protect consumers from serious risks resulting from use of botanicals in food products such as herbal preparations.
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