Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 218

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==obesity
Check title to add to marked list
B Vitamins Can Reduce Body Weight Gain by Increasing Metabolism-related Enzyme Activities in Rats Fed on a High-Fat Diet
Zheng, Ying ; Ma, A. ; Zheng, Ming C. ; Wang, Qiuzhen ; Liang, Hui ; Han, Xiuxia ; Schouten, Evert G. - \ 2018
Current Medical Science 38 (2018)1. - ISSN 2096-5230 - p. 174 - 183.
B vitamins - body weight gain - enzyme activities - obesity - rats

B vitamins are enzyme cofactors that play an important role in energy metabolism. The aim of this study was to elucidate whether B vitamin administration can reduce body weight (BW) gain by improving energy metabolism-related enzyme activities in rats fed on a highfat diet. Fifty rats were randomly assigned to one of the following five groups: control group (C), including rats fed on standard rat chow; four treatment groups (HO, HI, H2, and H3), in which rats were fed on a high-fat diet. Rats in the HI group were treated daily with 100 mg/kg BW thiamine (VB1), 100 mg/kg BW riboflavin (VB2), and 250 mg/kg BW niacin (VPP); rats in the H2 group were treated daily with 100 mg/kg BW pyridoxine (VB6), 100 mg/kg BW cobalamin (VB12), and 5 mg/kg BW folate (FA); and rats in the H3 group were treated daily with all of the B vitamins administered to the HI and H2 groups. After 12 weeks, the BW gains from the initial value were 154.5±58.4 g and 159.1±53.0 g in the HI and C groups, respectively, which were significantly less than the changes in the HO group (285.2±14.8 g, P<0.05). In the HO group, the plasma total cholesterol (CHO) and triglyceride (TG) levels were 1.59±0.30 mmol/L and 1,55±0.40 mmol/L, respectively, which were significantly greater than those in the HI group (1.19±0.18 mmol/L and 0.76±0.34 mmol/L, respectively, P<0.05). The activities of transketolase (TK), glutathione reductase, and Na+/K+ adenosine triphosphatase were significantly increased in the B vitamin-treated groups and were significantly greater than those in the HO group (P<0.05). Furthermore, the glucose-6-phosphate dehydrogenase, pyruvic acid kinase, and succinate dehydrogenase activities also were increased after treatment with B vitamins. Supplementation with B vitamins could effectively reduce BW gain and plasma levels of lipids by improving energy metabolism-related enzyme activities in rats, thus possibly providing potential benefits to humans.

Data and analysis of diet-induced and obesity-associated alterations of gut microbiota of 129S6/Sv and C57BL/6J mice
Xiao, Liang ; Sonne, Si Brask ; Feng, Qiang ; Chen, Ning ; Xia, Zhongkui ; Li, Xiaoping ; Fang, Zhiwei ; Fjære, Even ; Derrien, M.M.N. ; Hugenholtz, F. ; Kleerebezem, M. - \ 2017
PRJEB10308 - ERP011540 - C57BL/6J mice - 129S6/Sv mice - obesity - high fat feeding - microbiota - indomethacin
High fat feeding rather than obesity drives taxonomical and functional changes in the gut microbiota in mice. It is well known that the microbiota of high fat (HF) diet-induced obese mice differs from that of lean mice, but to what extent this difference reflects the obese state or the diet is unclear. To dissociate changes in the gut microbiota associated with high HF feeding from those associated with obesity, we took advantage of the different susceptibility of C57BL/6JBomTac (BL6) and 129S6/SvEvTac (Sv129) mice to diet-induced obesity and of their different responses to inhibition of cyclooxygenase (COX) activity, where inhibition of COX activity in BL6 mice prevents HF diet-induced obesity, but in Sv129 mice accentuates obesity. Using HiSeq-based whole genome sequencing we identified taxonomic and functional differences in the gut microbiota of the two mouse strains fed regular low fat or HF diets with or without supplementation with the COX-inhibitor, indomethacin. Here we present the sequence assemblies and annotations for those 54 samples, together with the gene catalogue and relevative abundance levels of both genes and OTUs. It is hoped these data can be used for comparison in future studies of a similar design.
Data from: Intestinal Ralstonia pickettii augments glucose intolerance in obesity
Udayappan, Shanthadevi D. ; Kovatcheva-Datchary, Petia ; Bakker, Guido J. ; Havik, Stefan R. ; Herrema, Hilde ; Cani, Patrice D. ; Bouter, Kristien E. ; Belzer, C. ; Witjes, Julia J. ; Vrieze, Anne ; Sonnaville, Noor De; Chaplin, Alice ; Raalte, Daniël H. van; Aalvink, S. ; Dallinga-Thie, Geesje M. ; Heilig, G.H.J. ; Bergström, Göran ; Meij, Suzan Van Der; Wagensveld, Bart A. Van; Hoekstra, Joost B.L. ; Holleman, Frits ; Stroes, Erik S.G. ; Groen, Albert K. ; Bäckhed, Fredrik ; Vos, W.M. de; Nieuwdorp, Max - \ 2017
microbiome - obesity - glucose intolerance - inflammation - Ralstonia pickettii
An altered intestinal microbiota composition has been implicated in the pathogenesis of metabolic disease including obesity and type 2 diabetes mellitus (T2DM). Low grade inflammation, potentially initiated by the intestinal microbiota, has been suggested to be a driving force in the development of insulin resistance in obesity. Here, we report that bacterial DNA is present in mesenteric adipose tissue of obese but otherwise healthy human subjects. Pyrosequencing of bacterial 16S rRNA genes revealed that DNA from the Gram-negative species Ralstonia was most prevalent. Interestingly, fecal abundance of Ralstonia pickettii was increased in obese subjects with pre-diabetes and T2DM. To assess if R. pickettii was causally involved in development of obesity and T2DM, we performed a proof-of-concept study in diet-induced obese (DIO) mice. Compared to vehicle-treated control mice, R. pickettii-treated DIO mice had reduced glucose tolerance. In addition, circulating levels of endotoxin were increased in R. pickettii-treated mice. In conclusion, this study suggests that intestinal Ralstonia is increased in obese human subjects with T2DM and reciprocally worsens glucose tolerance in DIO mice.
Between odours and overeating : behavioural and neurobiological mechanisms of olfactory food-cue reactivity
Zoon, Harriët F.A. - \ 2017
University. Promotor(en): Kees de Graaf, co-promotor(en): Sanne Boesveldt. - Wageningen : Wageningen University - ISBN 9789463431675 - 178
geurstoffen - overeten - neurobiologie - voedingsgedrag - reukstimulatie - obesitas - eetlust - overgewicht - buik bypass - verzadigdheid - odours - overeating - neurobiology - feeding behaviour - olfactory stimulation - obesity - appetite - overweight - gastric bypass - satiety

The obesogenic environment we live in is characterized by an abundance of available foods and food cues that tempt us to eat. Throughout our lives we learn to associate these food cues (odours, pictures) with physiological consequences of food consumption. The sense of smell is suggested to be very important for determining food quality, guiding us away from spoilt food and towards rewarding foods. Increased sensitivity to environmental cues of rewarding food, decreased sensitivity to physiological cues of hunger and a decreased ability to control impulses are thought to contribute to overeating and obesity. With the research in this thesis we aimed to elucidate the role of odours in (over)eating, to better understand how sensory food cues and hunger feelings are involved in determining our eating pattern.

We assessed the appetizing effects of exposure to odours signalling food with a certain taste (sweet/savoury) and energy density (high/low). Our findings show that smelling a food odour increases appetite for foods that are similar to the odour, both in terms of taste and energy density. These appetizing effects were present when participants were hungry but also when they had just eaten, indicating a possible role in overeating.

Further, consumption of a high-energy food with a certain taste (sweet/savoury) led to a decrease in liking and wanting of foods with a similar taste and energy density. Next to this, we observed more pronounced changes in early neural processing of pictures of high-energy/sweet food after consumption of a high-energy/sweet meal.

Food preferences and -intake after ambient exposure to odours signalling high-energy food, low-energy food and non-food were not different. Odours did not affect these measures of eating behaviour differently in a hungry or satiated state and in normal-weight or overweight participants.

In a group of patients who underwent Roux-en-Y Gastric Bypass weight-loss surgery, we found a shift in food preferences away from high-fat/high-sugar and towards low-fat/low-sugar foods and altered activation in the frontoparietal neural network during (food) cue processing. After compared to before surgery we also found altered prefrontal neural responses when patients inhibited their responses to pictures of high-energy food. These results suggest that RYGB leads to changes in cognitive control of attention and increased neural inhibitory control over behavioural responses.

In conclusion, odours have a specific appetizing function in the anticipatory phase of eating. They are important in determining the taste quality and energy-density and may be involved in the selection of foods for macronutrient regulation. Orthonasal odours should be used to guide food selection towards a healthier eating pattern.

Endocannabinoids derived from n-3 PUFAs - Formation, release and possible roles in inflammation and obesity
Wang, Ya - \ 2017
University. Promotor(en): Renger Witkamp, co-promotor(en): Jocelijn Meijerink; Jean-Paul Vincken. - Wageningen : Wageningen University - ISBN 9789463432016 - 195
polyunsaturated fats - health promotion - obesity - inflammation - cannabinoids - neurology - energy restricted diets - meervoudig onverzadigde vetten - gezondheidsbevordering - obesitas - ontsteking - cannabinoïden - neurologie - energiearme diëten

The fatty acid composition of our daily diet is considered a major determinant of long-term health risk and the development of disease. Several lines of evidence point toward a state of chronic ‘low-grade’ inflammation as an overarching process that is modulated by fatty acids and their different metabolites. Diets rich in omega-3 polyunsaturated fatty acids (PUFAs), among which docosahexaenoic acid (22:6n-3; DHA) have been found to be associated with a reduction of inflammatory activity. However, the mechanisms underlying these immune-modulatory effects of n-3 PUFAs are only partly known. Earlier data from our group and from other labs have provided evidence for an as yet largely unexplored mechanism involving the formation of DHA-derived fatty acid amides. Fatty acid amides (FAAs) are a group of lipids formed from fatty acids and biogenic amines, which are widely occurring in nature. An increasing number of FAAs, including conjugates of fatty acids with neurotransmitters and mono-amines, have been detected as endogenous molecules in different cells and tissues. However, their bioactivities have remained largely unknown so far.

In the first experimental part (chapter 2 and 3) of this thesis, we explored the immune-modulatory profiles of two relatively unknown DHA-derived FAAs conjugates with dopamine and serotonin, respectively. In chapter 2, we enzymatically synthesised the dopamine conjugate of DHA, N-docosahexaenoyl dopamine (DHDA), and demonstrated that DHDA significantly suppressed the production of several mediators involved in (neuro-)inflammation. We showed that these immune-modulatory effects involved the enzyme cyclooxygenase-2 (COX-2), as its gene-expression and (or) production of its metabolite PGE2 were down-regulated by DHDA in both activated macrophages as well as microglia. Additionally, the immune-modulatory activities of DHDA were compared with those of N-arachidonoyl dopamine (NADA) and similar potencies were found in the cell types tested. In chapter 3, we investigated the effects of docosahexaenoyl serotonin (DHA-5-HT), the serotonin conjugate of DHA on inflammatory processes in human PBMCs. By comparing the immune-modulatory potencies of 6 serotonin-conjugates with palmitic acid (PA-5-HT), stearic acid (SA-5-HT), oleic acid (OA-5-HT), arachidonic acid (AA-5-HT), eicosapentaenoic acid (EPA-5-HT) and docosahexaenoic acid (DHA-5-HT), DHA-5-HT turned out to exert the strongest inhibitory effects on the production of IL-17 from ConA-stimulated human PBMCs. Furthermore, DHA-5-HT concentration-dependently inhibited the production of IL-17 and CCL-20, two important Th17 mediators involved in the pathogenesis of IBD. Also, we demonstrated the in vivo presence of N-acyl serotonins in human intestine. Taken together, we revealed the immune-modulatory effects of two n-3 PUFA-derived fatty acid amides with thus far largely unknown functions and showed that these compounds were far more potent than its parent compound DHA. These findings were shown not only for innate inflammatory processes in stimulated mouse macrophages, but were also found to be present in human PBMCs and likely involved the adaptive CD4+ Th17 response.

In order to study the effects of dietary omega-3 fatty acids on endocannabinoid tone in relation to obesity and metabolic health, a parallel-designed, randomized human study was conducted in the second part of the thesis. In this 12 weeks intervention hundred men and women with abdominal obesity were assigned to either a Western type energy restricted (ER) diet, a Targeted ER diet or a control group. The two ER diet groups were both subjected to energy restriction but their diets differed in nutrient composition. The traditional, more Western-style diet (Western ER diet) included both saturated as well as unsaturated fats, whereas the Targeted ER diet was amongst others enriched with monounsaturated fatty acids (MUFAs) and polyunsaturated fatty acids (PUFAs). This intervention resulted in significant weight loss and significant improvements of metabolic parameters in both energy restriction (ER) dietary intervention groups. In chapter 4, we revealed that the two weight loss regimes (ER-diets) with different fatty acid composition did not significantly affect fasting peripheral levels of AEA and 2-AG in both plasma and abdominal adipose tissues. By contrast, plasma DHEA was found to be significantly decreased in the Western ER group compared with the Targeted ER group. Additionally, circulating EC-related compounds DHEA, DHAGly, PEA and SEA were significantly decreased in the Western ER diet group after intervention. Furthermore, decreased levels of DHEA were positively associated with body weight reduction. In chapter 5, by performing a high calorie mixed meal test (MMT) before and after the intervention, we found that postprandial AEA and 2-AG levels were significantly reduced in the targeted ER group upon the intervention. By contrast, the DHA-derived compounds DHEA and DHAGly showed a significant increase in the Targeted ER group after 12 weeks of intervention. Additionally, all measured endocannabinoids and related compounds, with the exception of 2-AG, showed a similar characteristic time curve in response to the MMT, with EC levels reaching their highest concentration as early as 5 minutes after food intake (T=10min in experiment).

In conclusion, we showed here that two largely unknown amidated DHA conjugates are more potent mediators of inflammatory processes than their parent compound DHA. These findings support our previously proposed idea that DHA-derived FAAs play a role in the underlying mechanism of the beneficial health effects of DHA. We further uncovered that a combination of ER and n-3 PUFAs in the diet alters the postprandial endocannabinoid tone. Given the fact that the endocannabinoid system (ECS) plays an important role in both the central and peripheral regulation of food intake and energy homeostasis, these findings provide new insights in the potentially mechanisms involved in an over-activated endocannabinoid system during obesity.

External cues challenging the internal appetite control system—Overview and practical implications
Bilman, Els ; Kleef, Ellen van; Trijp, Hans van - \ 2017
Critical Reviews in Food Science and Nutrition 57 (2017)13. - ISSN 1040-8398 - p. 2825 - 2834.
Food environment - food intake - obesity - satiation - satiety
Inadequate regulation of food intake plays an important role in the development of overweight and obesity, and is under the influence of both the internal appetite control system and external environmental cues. Especially in environments where food is overly available, external cues seem to override and/or undermine internal signals, which put severe challenges on the accurate regulation of food intake. By structuring these external cues around five different phases in the food consumption process this paper aims to provide an overview of the wide range of external cues that potentially facilitate or hamper internal signals and with that influence food intake. For each of the five phases of the food consumption process, meal initiation, meal planning, consumption phase, end of eating episode and time till next meal, the most relevant internal signals are discussed and it is explained how specific external cues exert their influence.
How to measure health improvement? : assessment of subtle shifts in metabolic phenotype
Fazelzadeh, Parastoo - \ 2017
University. Promotor(en): Sander Kersten; John van Duynhoven, co-promotor(en): Mark Boekschoten. - Wageningen : Wageningen University - ISBN 9789463430739 - 187
health promotion - improvement - measurement - metabolic profiling - elderly - obesity - microarrays - rna - peripheral blood mononuclear cells - gezondheidsbevordering - verbetering - meting - metabolische profilering - ouderen - obesitas - perifere mononucleaire bloedcellen

Human health is impacted by a complex network of interactions between biological pathways, mechanisms, processes, and organs, which need to be able to adapt to a continuously changing environment to maintain health. This adaptive ability is called ‘phenotypic flexibility’. It is thought that health is compromised and diseases develop when these adaptive processes fail. As the product of interactions between several factors such as genetic makeup, diet, lifestyle, environment and the gut microbiome, the ‘metabolic phenotype’ provides a readout of the metabolic state of an individual. Understanding these relationships will be one of a major challenges in nutrition and health research in the next decades. To address this challenge, the development of high-throughput omics tools combined with the application of elaborate statistical analyses will help characterize the complex relationship of (bio) chemicals in human systems and their interaction with other variables including environment and lifestyle to produce the measured phenotype. An important aim of this thesis was to identify phenotype shifts by looking at effect of prolonged resistance-type exercise training on skeletal muscle tissue in older subjects and the possible shift toward the features of younger subjects as a reference for a healthier phenotype. A second aim was to identify phenotype shifts by looking at the response to a challenge in obese subjects and the possible shift toward lean subjects as a reference for a healthier phenotype.

Chapter 2 and 3 of this thesis show how the significant remaining plasticity of ageing skeletal muscle can adapt to resistance-type exercise training. The data indicate that frail and healthy older subjects have two distinct phenotypes according to the skeletal muscle tissue metabolite profiles and that exercise training shifts aged muscle towards a younger phenotype. We showed that the effect of exercise on amino acid derived acylcarnitines (AAAC’s) in older subjects points towards decreased branched chain amino acid catabolism, likely due to compromised activation of the branched chain α-keto acid hydrogenase (BCKDH) complex. Furthermore, we found that the protocadherin gamma gene cluster might be involved in aged-muscle denervation and re-innervation. Finally, plasma was found to be a poor indicator of muscle metabolism, emphasizing the need for direct assessment of metabolites in muscle tissue.

Chapter 4 of this thesis examines whether a mixed meal challenge response provides a readout for a shift in phenotype upon weight loss in obese male subjects. We concluded that weight loss moderately affects the mixed meal challenge response of both plasma metabolome and transcriptome of peripheral blood mononuclear cells in obese subjects. Measurements at the fasted and postprandial state also provide us with a different type of information.

In Chapter 5 it is demonstrated that the global testing of pathways could provide a concise summary of the multiple univariate testing approach used in Chapter 4. In Chapter 6 it is discussed how the findings of this thesis increase our understanding of how to measure phenotypic flexibility as a proxy of health. In this thesis it is shown that the correlations between tissue and plasma metabolites are rather weak, emphasising the need to perform organ-specific studies. Availability of less invasive/painful sampling techniques and the use of small amounts of tissue would enable larger scale human studies on adipose tissue and skeletal muscle to more accurately define phenotypical shifts due to diet or lifestyle interventions. With respect to the assessment of phenotypical flexibility by omics approaches, significant complications can be expected in trying to relate plasma metabolism to PBMC gene expression. Organ-focussed approaches that integrate multiple omics levels using system biology approaches are considered to be a lot more promising.

Food-grade Micro-encapsulation Systems that May Induce Satiety via Delayed Lipolysis: A Review
Corstens, M.N. ; Berton-Carabin, C.C. ; Vries, R.J. de; Troost, F.J. ; Masclee, A.A.M. ; Schroen, C.G.P.H. - \ 2017
Critical Reviews in Food Science and Nutrition 57 (2017)10. - ISSN 1040-8398 - p. 2218 - 2244.
In vitro digestion - Ileal brake - emulsion - Food - obesity
The increasing prevalence of overweight and obesity requires new, effective prevention and treatment strategies. One approach to reduce energy intake is by developing novel foods with increased satiating properties, which may be accomplished by slowing down lipolysis to deliver substrates to the ileum, thereby enhancing natural gut-brain signalling pathways of satiety that are normally induced by meal intake. To develop slow release food additives, their processing in the gastrointestinal tract has to be understood; therefore, we start from a general description of the digestive system and relate that to in vitro modelling, satiety and lipolytic mechanisms. The effects of physicochemical lipid composition, encapsulation matrix and interfacial structure on lipolysis are emphasized. We give an overview of techniques and materials used, and discuss partitioning, which may be a key factor for encapsulation performance. Targeted release capsules that delay lipolysis form a real challenge because of the high efficiency of the digestive system; hardly any proof was found that intact orally ingested lipids can be released in the ileum and thereby induce satiety. We expect that this challenge could be tackled with structured o/w-emulsion-based systems that have some protection against lipase, e.g., by hindering bile salt adsorption and/or delaying lipase diffusion.
Goede voeding voor het hart : zorg dat het klopt
Geleijnse, Marianne - \ 2016
Wageningen : Wageningen University & Research - ISBN 9789463430234 - 32
gezondheidsgedrag - voeding en gezondheid - hart- en vaatziekten - obesitas - roken - zout - levensstijl - health behaviour - nutrition and health - cardiovascular diseases - obesity - smoking - salt - lifestyle
Mining the human intestinal microbiota for biomarkers associated with metabolic disorders
Hermes, Gerben - \ 2016
University. Promotor(en): Hauke Smidt; Erwin Zoetendal. - Wageningen : Wageningen University - ISBN 9789462579514 - 205
gastrointestinal microbiota - metabolic disorders - biomarkers - obesity - intestinal microorganisms - antibiotics - dna sequencing - rna - ribosomal rna - microbiota van het spijsverteringskanaal - stofwisselingsstoornissen - obesitas - darmmicro-organismen - antibiotica - dna-sequencing - ribosomaal rna

After birth, our gastrointestinal (GI) tract is colonized by a highly complex assemblage of microbes, collectively termed the GI microbiota, that develop intimate interactions with our body. Recent evidence indicates that the GI microbiota and its products may contribute to the development of obesity and related diseases. This, coupled with the current worldwide epidemic of obesity, has moved microbiome research into the spotlight of attention. Although the main cause of obesity and its associated metabolic complications is excess caloric intake compared with expenditure, differences in GI tract microbial ecology between individuals might be an important biomarker, mediator or even new therapeutic target. Nevertheless, it is currently still unclear which bacterial groups play a role in the development of the metabolic syndrome in humans. This might partly be explained by: 1. Biological factors such as the heterogeneity in genotype, lifestyle, diet; and the often complex aetiology of human disease of which the metabolic syndrome is no exception. 2. Technological factors, such as the use of miscellaneous incompatible methods to assess the gut microbiota, often enumerating specific groups rather than using broad 16S rRNA gene surveys or metagenomics. 3. Studies vary greatly in the populations considered, their designs, and the degree of control for potential confounding factors such as lifestyle and diet. Nevertheless, recent research on this matter has shown a conceptual shift by focusing on more homogenous subpopulations, based on stricter control over variables such age range or through the use of both anthropometric (weight, total body fat) as well as biochemical variables (insulin resistance, hyperlipidaemia) to define groups.

Perturbations in microbial diversity and community structure in adults with overweight and obesity may be partly due to long-term dietary habits or physiological changes in these subjects. As such, exploring the association between the gut microbiota and variation in BMI and weight in early life, prior to or close to the onset of overweight, might provide additional insights into these processes. Therefore, we studied the fecal microbiota of 295 six-seven year old children from the KOALA Birth Cohort, living in the south of the Netherlands. This age range is relatively uncharted microbiota territory. We found that its composition seems to conform to tot same ecosystem rules as that of adults. The bimodal distribution pattern of several bacterial groups as well as their co-correlating groups that were reported previously, including Uncultured Clostridiales II (UCII), Prevotella spp. and Dialister were confirmed. Furthermore, one of the previously described bimodal groups (Uncultured Clostridiales I) was shown before to exhibit very clear shifting state probabilities associated with ageing, where the high abundance state was mainly observed above 40 years of age. This was corroborated as no support for bimodality of this group was observed in the children included in the study described here. A large part of the variation in microbiota composition was explained by the abundance of aforementioned groups in contrast to the anthropometric outcomes, suggesting that in this group of healthy children within a relatively normal weight range, weight and associated parameters were not major drivers of overall genus-level microbial composition or vice versa. Hereafter, multiple linear and logistic regression models with rigorous adjustment for confounders were applied to investigate individual microbiota features association with weight related anthropometric outcomes. Previously reported parameters such as diversity, richness and Bacteroidetes to Firmicutes ratio, were not significantly associated with any of the outcomes. Nevertheless, the abundance of several specific bacterial taxa; Akkermansia, Sutterella wadsworthia et rel. and Bryantella formatexigens et rel. and the dichotomous abundance state of the bi-modally distributed UCII was consistently associated with weight-related outcomes.

Other biochemical features of the metabolic syndrome have been associated with the gut microbiome. Mainly rodent studies have indicated that antibiotic treatment may improve glucose homeostasis and metabolic impairments. Therefore, the effects of gut microbiota manipulation by antibiotics (7d administration of amoxicillin, vancomycin or a placebo) on tissue-specific insulin sensitivity, energy metabolism, gut permeability and inflammation in 57 obese, pre-diabetic men from the same geographical region, were investigated. Vancomycin decreased bacterial diversity and significantly reduced well known butyrate- producing Firmicutes from Clostridium clusters IV and XIVa and bacterial groups involved in bile acid metabolism. These changes occurred concomitantly with altered plasma and fecal concentrations of these metabolites. In adipose tissue, gene expression of oxidative pathways was upregulated by antibiotics, whereas immune-related pathways were downregulated by vancomycin. However, antibiotic treatment had no significant effects on tissue-specific insulin sensitivity, energy/substrate metabolism, postprandial hormones and metabolites, systemic inflammation, gut permeability and adipocyte size. Importantly, despite a still considerably altered microbial composition at eight weeks follow-up, energy harvesting, adipocyte size and whole-body insulin sensitivity (HOMA-IR) remained unaltered. Overall these data indicate that interference with adult microbiota by antibiotic treatment for 7 days had no clinically relevant impact on metabolic health in obese humans. These data are in contrast with several rodent studies as well as a human intervention. The present study, which was well-powered and placebo-controlled, indicates that the previously reported vancomycin-induced effects on human peripheral insulin sensitivity are probably of minor physiological significance.

The aforementioned group that was relatively homogeneous with regards to phenotype was combined with another cohort with similar phenotypical characteristics (obese, male and pre-diabetic) from another region of the Netherlands, to investigate whether tissue specific insulin sensitivity, as measured by the golden standard hyperinsulinemic-euglycemic clamp technique, is related to a specific microbial pattern. Remarkably, despite the fact that both cohorts were constructed based on comparable recruitment strategies, the average microbiota composition in both cohorts showed pronounced differences. Firstly, we found no consistent and significant association between liver, adipose tissue or skeletal muscle insulin sensitivity and the microbiota in both cohorts. Nevertheless, Random Forests classifiers using microbiota composition as predictors revealed taxa associated with fasting glucose concentrations and HbAc1 but only in one cohort. The top microbial features distinguishing classes were different Proteobacteria and groups involved in butyrogenesis, such as Faecalibacterium prausnitzii, Roseburia intestinalis, and Eubacterium rectale and related species, for fasting glucose levels. For HbAc1 these taxa were Oscillospira guillermondii, Sporobacter termitidis, Lactobacillus gasseri and Peptococcus niger and related species. The striking cohort-specific observations suggest that the relation between microbiota composition and type 2 diabetes mellitus as well as other characteristics of the metabolic syndrome is very dependent on the selected cohort of patients and their respective baseline microbiota composition. Similar observations have been made by other researchers as well. It could be that differences in microbiota composition are not associated with the insulin resistance phenotype when the overweight and/or obese state of the patient is already established, as is the case for our metabolic syndrome patients. In the latter case we cannot exclude that the composition of the fecal microbiota may play a role in the worsening of insulin sensitivity in an early stage in the development from a lean towards an overweight/obese phenotype. Furthermore, the observation of a subgroup- specific microbiota only observed in one of the cohorts might indicate an alternative state of microbiota composition driven by yet unknown forces. Nevertheless, this study clearly demonstrated that cohort-specific microbiota differences hamper finding a consensus biological interpretation between cross-sectional studies. This, combined with the complexity of individual disease pathogenesis, as well as the individual-specific differences in microbiota composition, may explain the inconsistency in observations between different studies concerning the identification of signature microbes for obesity, irritable bowel syndrome and other diseases.

Besides the biological drivers for cohort specific inconsistencies in identified microbial biomarkers, there are also technological factors. Although high-throughput sequencing of short, hypervariable segments of the 16S ribosomal RNA (rRNA) gene has transformed the methodological landscape describing microbial diversity within and across complex biomes, evidence is increasing that methodology rather than the biological variation is responsible for observed sample composition and distribution. Large meta-analyses would aid in elucidating whether the basis for these observed inconsistencies is biological, technical or maybe a combination of both. To facilitate these meta-analyses of microbiota studies we developed NG-Tax, a pipeline for 16S rRNA gene amplicon sequence analysis that was validated with different Mock Communities (MC). NG-Tax demonstrated high robustness against choice of region and other technical biases associated with 16S rRNA gene amplicon sequencing studies. The analysis of α- and β-diversity of these MC confirmed conclusions guided by biology rather than the methodological aspects. This pipeline was applied to biological samples to monitor the developing communities an in vitro gut model (TIM-2) fed either with a normal diet, or modified versions from which the carbohydrate (MPLC) or protein fraction was diluted (LPMC) for 72h. In combination with global metatranscriptomics and metabolomics this revealed that each diet produced distinct microbial communities and temporal patterns and ratios of metabolites. The microbiota in reactors fed diets containing normal carbohydrate levels were enriched in members of the genera Prevotella, Subdoligranulum, Blautia and Bifidobacterium, all associated with carbohydrate fermentation. In turn, the microbiota in the reactors fed the MPLC diet, containing ten-fold less carbohydrates, was enriched in the genus Bacteroides, which is associated with diets rich in protein and animal fat. This setup allows researchers to study the (trophic) interactions and task division within a community and how they are impacted by diet-related factors under controlled conditions, which may assist in defining causal links between specific diet-derived parameters microbial groups and their activities.

In conclusion, currently it seems that GI microbiota based biomarkers associated with metabolic impairments and anthropometric variables associated with the metabolic syndrome are cohort specific or possibly individual, which could partly be due to the use of incompatible analytical approaches. Nevertheless, there is growing evidence that human health is a collective property of the human body and its associated microbiome and thus requires to study the interface of two very complex systems, i.e. on one side the extraordinary coding capacity, high inter-individuality and complex dynamics of the microbiome and on the other side the multifactorial individual nature of human disease. In light of these observations the manifestation of individual dynamics of the microbiota with the host when homeostasis is lost seems plausible and likely.

Anthropometry and the risk of lung cancer in EPIC
Dewi, Nikmah Utami ; Boshuizen, Hendriek C. ; Johansson, Mattias ; Vineis, Paolo ; Kampman, Ellen ; Steffen, Annika ; Tjønneland, Anne ; Halkjær, Jytte ; Overvad, Kim ; Severi, Gianluca ; Fagherazzi, Guy ; Boutron-Ruault, Marie Christine ; Kaaks, Rudolf ; Li, Kuanrong ; Boeing, Heiner ; Trichopoulou, Antonia ; Bamia, Christina ; Klinaki, Eleni ; Tumino, Rosario ; Palli, Domenico ; Mattiello, Amalia ; Tagliabue, Giovanna ; Peeters, Petra H. ; Vermeulen, Roel ; Weiderpass, Elisabete ; Gram, Inger Torhild ; Huerta, José María ; Agudo, Antonio ; Sánchez, María José ; Ardanaz, Eva ; Dorronsoro, Miren ; Quirós, José Ramón ; Sonestedt, Emily ; Johansson, Mikael ; Grankvist, Kjell ; Key, Tim ; Khaw, Kay Tee ; Wareham, Nick ; Cross, Amanda J. ; Norat, Teresa ; Riboli, Elio ; Fanidi, Anouar ; Muller, David ; Bueno-De-Mesquita, H.B. - \ 2016
American Journal of Epidemiology 184 (2016)2. - ISSN 0002-9262 - p. 129 - 139.
body mass index - lung cancer - obesity - smoking - waist circumference - waist to hip ratio - waist-to-height ratio

The associations of body mass index (BMI) and other anthropometric measurements with lung cancer were examined in 348,108 participants in the European Investigation Into Cancer and Nutrition (EPIC) between 1992 and 2010. The study population included 2,400 case patients with incident lung cancer, and the average length of follow-up was 11 years. Hazard ratios were calculated using Cox proportional hazard models in which we modeled smoking variables with cubic splines. Overall, there was a significant inverse association between BMI (weight (kg)/height (m)2) and the risk of lung cancer after adjustment for smoking and other confounders (for BMI of 30.0-34.9 versus 18.5-25.0, hazard ratio = 0.72, 95% confidence interval: 0.62, 0.84). The strength of the association declined with increasing follow-up time. Conversely, after adjustment for BMI, waist circumference and waist-to-height ratio were significantly positively associated with lung cancer risk (for the highest category of waist circumference vs. the lowest, hazard ratio = 1.25, 95% confidence interval: 1.05, 1.50). Given the decline of the inverse association between BMI and lung cancer over time, the association is likely at least partly due to weight loss resulting from preclinical lung cancer that was present at baseline. Residual confounding by smoking could also have influenced our findings.

Sierteelt in de biobased economy : Screening van siergewasextracten op werking voor de plantgezondheid en de farmacie : Ornamentals in the biobased economy
Poot, E.H. ; Staaij, M. van der; Hofland-Zijlstra, J.D. ; Vos, C.H. de; Korthout, H. ; Schulte, Annelies - \ 2016
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1387) - 52 p.
plantensamenstelling - plantextracten - biopesticiden - obesitas - medicinale eigenschappen - screenen - pesticiden bevattende planten - gewasbescherming - biobased economy - siergewassen - sierteelt - plant composition - plant extracts - microbial pesticides - obesity - medicinal properties - screening - pesticidal plants - plant protection - ornamental crops - ornamental horticulture
The public-private funded project “Ornamentals in the Biobased Economy” was conducted by Royal FloraHolland, Kenniscentrum Plantenstoffen, Wageningen UR, Fytagoras and Prisna. In this project, bioactivity in plant extracts against the most important pests and diseases in greenhouse cultivation were tested. In bioassays, extracts with bioactivity against powdery mildew, botrytis, aphids, spider mite and thrips were found. With LCMS, metabolic profiles of the extracts were generated. Furthermore explorative experiments with plant extracts for crop resilience were conducted, and also plant extracts were tested in a bioassay for fat metabolism in obesitas
Targeting persons with low socioeconomic status of different ethnic origins with lifestyle interventions : opportunities and effectiveness
Bukman, A.J. - \ 2016
University. Promotor(en): Edith Feskens, co-promotor(en): Reint-Jan Renes. - Wageningen : Wageningen University - ISBN 9789462577022 - 169 p.
socioeconomic status - lifestyle - ethnic groups - intervention - cardiovascular diseases - type 2 diabetes - diabetes - obesity - dutch - turkish - glucose tolerance - morocco - physical activity - prevention - sociaal-economische positie - levensstijl - etnische groepen - interventie - hart- en vaatziekten - diabetes type 2 - suikerziekte - obesitas - nederlands - turks - glucosetolerantie - marokko - lichamelijke activiteit - preventie

Lifestyle intervention studies have shown that the development of cardiometabolic diseases can be partly prevented or postponed by the combination of a healthy diet and physical activity. Cardiometabolic diseases and their risk factors are particularly prevalent among individuals with low socioeconomic status and some ethnic minorities, and therefore these groups especially may benefit from participating in lifestyle interventions. Although individuals with low socioeconomic status and ethnic minorities could potentially benefit from lifestyle interventions, it seems that these groups are often not successfully reached for such interventions. Moreover, when they do participate in these interventions, they seem more likely to quit. The overall aim of this thesis was therefore to study opportunities for, and the effectiveness of, lifestyle interventions to reduce the risk of cardiometabolic diseases, targeting individuals with low socioeconomic status of different ethnic origins. To this end, this thesis reports two studies that identified opportunities for adapting lifestyle interventions to the target group’s needs, one study describing the process of adapting an effective lifestyle intervention (SLIM) into a new lifestyle intervention targeting individuals with low SES of different ethnic origins (MetSLIM) and two studies that determined the effectiveness of lifestyle interventions among the target group.

The aim of the study described in chapter 2 was to identify opportunities for adapting lifestyle interventions in such a way as to be more appealing for individuals with low socioeconomic status. The study provided insight into perspectives of groups with different socioeconomic positions regarding their current eating and physical activity behaviour; triggers for lifestyle change; and preferred ways to support lifestyle change. Data were gathered in semi-structured focus group interviews with adults with low socioeconomic status (four groups) and with adults with high socioeconomic status (five groups). In general, three key topics were identified, namely: current lifestyle is logical for participants given their personal situation; lifestyle change is prompted by feedback from their body; and support for lifestyle change should include individually tailored advice and could profit from involving others. The perceptions of the participants with low socioeconomic status were generally comparable to the perceptions shared by the participants with high socioeconomic status. Some perceptions were, however, especially mentioned in the low socioeconomic status groups. Participants with low socioeconomic status indicated that their current eating behaviour was sometimes affected by cost concerns. They seemed to be especially motivated to change their lifestyle when they experienced health complaints but were rather hesitant to change their lifestyle for preventive purposes. Regarding support for lifestyle change, participants with low socioeconomic status preferred to receive advice in a group rather than on their own. For physical activities, groups should preferably consist of persons of the same age, gender or physical condition.

The aim of the study described in chapter 3 was to identify how Turkish and Moroccan adults living in the Netherlands, aged 45 years and older, could be reached to participate in health checks for cardiometabolic diseases and follow-up (lifestyle) advice. In this study, questionnaire data were combined with interview data. This was done in order to use the narratives from the interviews to get a better understanding of the numbers that resulted from the questionnaire data. It turned out that both ethnic groups preferred an invitation from their general practitioner (GP) for a health check and preferred to fill out the health check questionnaire at the GP’s office or at home, on paper. They preferred to receive advice at individual level in relation to personal matters via either a physician or a specialised healthcare professional. Sixty-one percent of the Turkish respondents preferred to receive information in their native language, compared to 37% of the Moroccan respondents. Several participants mentioned a low proficiency in the local language as an explanation for their preference to fill out the health check questionnaire at home, to receive advice from an ethnicity-matched professional and to receive information in their native language. The results of this study suggested that the GP would be a promising contact to reach adults of Turkish and Moroccan origin for health checks or (lifestyle) advice. Furthermore, the findings suggested that it would be necessary to provide information in individuals’ native language to overcome language barriers and that (lifestyle) advice should be tailored towards the needs of the targeted individuals.

The insights gained into the needs and preferences of the target group – as described in chapter 2 and chapter 3 – were taken into account in the design of the MetSLIM intervention study. The MetSLIM study targeted individuals with low socioeconomic status of Dutch, Turkish and Moroccan origin. The MetSLIM study protocol was based on the SLIM study protocol. The SLIM study showed the beneficial effects of nutrition advice and physical activity promotion on the prevention type 2 diabetes, but drop-out was relatively high among low SES participants. Chapter 4 provides a detailed description of the development from the SLIM study protocol to the MetSLIM study protocol. Furthermore, this chapter gives insight into the obstacles encountered in developing the MetSLIM study to target individuals with low socioeconomic status of different ethnic origins. The new elements regarding the lifestyle intervention programme were: 1) additional group meetings about price concerns and social occasions with regard to a healthy diet; 2) ethnicity-matched dieticians; 3) gender-matched sports instructors; 4) all activities in the participants’ own neighbourhood; and 5) activities for women and men separately. The new elements regarding the study design, in order to study the effectiveness of the MetSLIM intervention programme, included: 1) from an university stetting to a community setting; 2) from a randomised controlled trial to a quasi-experimental study; 3) waist circumference – as a visible cardiometabolic risk factor – as main study outcome; 4) recruitment via GPs and in community centres; 5) translated study materials and ethnicity-matched research assistants involved in measuring; and 6) fewer measurements and measurements that could take place at different locations. Adaptations to the original SLIM study protocol were considered necessary in order to overcome practical barriers that hinder the target group’s participation; to suit the target group’s (cultural) needs; and to make it feasible to perform the study in a local (community) setting.

MetSLIM was not the only study set up based on the SLIM study. The SLIMMER study translated SLIM from a university setting to a real-world setting. The intervention was implemented in the public health and primary healthcare setting involving local GPs, practice nurses, dieticians, physiotherapists and sports clubs. The SLIMMER study did not target individuals with low socioeconomic status in particular; however, 52% of the study participants did have a low socioeconomic status, as determined by highest completed educational level. Chapter 5 describes how we explored the role of socioeconomic status in willingness to participate, programme attendance, programme acceptability, adherence to lifestyle guidelines, drop-out and effectiveness in the SLIMMER diabetes prevention intervention. The SLIMMER study was a randomised controlled trial, targeting 40- to 70-year-old adults at increased risk of type 2 diabetes, carried out in Apeldoorn and Doetinchem. The intervention group participated in a 10-month lifestyle programme: weekly training sessions were guided by a physiotherapist, and dietary advice was given by a dietician during 5–8 individual consultations and one group session. Measurements were carried out at baseline, after 12 months and six months after the active intervention period ended. The study showed that participation, attendance, acceptability, adherence, drop-out and effect of the SLIMMER study were mostly not affected by socioeconomic status. The SLIMMER study was able to reach the low socioeconomic status group as effectively as the higher socioeconomic status group, resulting in at least similar health benefits. The SLIMMER sample size was too small to study differences within the low socioeconomic status group, e.g. comparing the low vs. the least educated or comparing ethnic groups. Only 10% of the 316 SLIMMER participants had the lowest educational levels (no education or primary education) and only 11% had a foreign background.

The aim of the study described in chapter 6 was to measure the effectiveness of the MetSLIM intervention on waist circumference and other cardiometabolic risk factors, lifestyle and quality of life among 30- to 70-year-old adults with an elevated waist-to-height ratio. In the MetSLIM study, 220 individuals participated, of whom 40% had no education or only primary education and of whom 64% had a foreign background. MetSLIM had a quasi-experimental design with measurements at baseline and after 12 months. Participants were recruited in deprived neighbourhoods of Arnhem and Eindhoven via either their GP or in community centres. The intervention group participated in a 12-month lifestyle programme: an introductory group meeting was guided by the researcher, weekly physical activity lessons were guided by a sports instructor and dietary advice was given by an ethnicity-matched dietician (in total four hours of individual consultations and three group sessions). The study showed that the MetSLIM lifestyle intervention was effective in reducing waist circumference, other measures of obesity, total and LDL cholesterol, and quality of life. MetSLIM had a drop-out of 31%, which was higher than at 12 months in the SLIM study (10%) and SLIMMER study (13%), but comparable to drop-out in similar studies among ethnic minorities or low socioeconomic status populations.

Finally, in chapter 7, the main results of this thesis are described, followed by a discussion of methodological considerations, public health implications, suggestions for future research and the general conclusion. The adaptation process from SLIM to MetSLIM is discussed, including a reflection on the decision to use SLIM as a starting point and the decision to target three different ethnic groups at the same time. Moreover, difficulties in defining and selecting persons with low socioeconomic status and specific ethnic groups within research are addressed. As SLIMMER and MetSLIM proved that low socioeconomic status populations can be reached, and that their health can be improved when they participate in lifestyle interventions, it is suggested that further implementation should be considered. Insight should be gained into the ‘black box’ of lifestyle interventions; i.e. we should get to know what works for whom. Planned future research includes a process and economic evaluation of MetSLIM.

This thesis has shown that intensive combined lifestyle interventions can be effective in low socioeconomic status populations and identified possible adaptations to make lifestyle interventions more suitable for individuals with low socioeconomic status of Dutch, Turkish and Moroccan origin. The question is not whether a lifestyle intervention can be effective, but how diverse groups can be reached and benefit from it. For this purpose, further insight into the success of different adaptations for different target groups should be obtained to reveal the effective elements to reach, inspire and retain different low socioeconomic status populations and ethnic minorities with lifestyle interventions.

Intestinal nutrient sensing : a gut feeling for food
Wielen, N. van der - \ 2016
University. Promotor(en): Renger Witkamp, co-promotor(en): Jocelijn Meijerink; Henk F.J. Hendriks. - Wageningen : Wageningen University - ISBN 9789462576995 - 200 p.
obesity - hormones - intestines - gastrointestinal hormones - pancreozymin - vasoactive intestinal peptide - sensing - in vivo experimentation - animal models - in vitro - gastric bypass - food - weight reduction - stevia rebaudiana - release - obesitas - hormonen - darmen - maagdarmhormonen - pancreozymine - vasoactief intestinaal peptide - aftasten - in vivo experimenten - diermodellen - buik bypass - voedsel - gewichtsvermindering - vrijgeven

The alarming increase in obesity rates creates an urgent need for effective prevention and treatment strategies. The most effective treatment for obesity today is bariatric surgery. Bariatric surgery comprises a number of different procedures having in common that they induce weight loss and alter gut hormone release. Gut hormones are well known for their effects on food intake behavior and their role in weight loss after bariatric surgery is undeniable. In addition, the therapeutic use of GLP-1 (Glucagon-Like Peptide-1) analogues including liraglutide in type II diabetes and obesity is on the rise. This underlines why gut hormones are considered promising targets for the development of new treatment strategies against obesity and its comorbidities.

The secretion of gut hormones, among which GLP-1, is influenced by nutrient ingestion. The interactions of dietary components or their breakdown products with receptors and transporters located on the enteroendocrine cells of the intestinal tract can induce their release, a process called intestinal nutrient sensing. In this thesis, we aimed to further elucidate intestinal nutrient sensing mechanisms on a cellular level. First, the regional expression of several gut nutrient sensing related genes along the intestinal tract was assessed in three commonly studied species, namely mouse, pig and man. Gene expression of receptors, transporters and peptides involved in nutrient sensing shows a distinctive distribution pattern along the small intestine, which is in the distal small intestine highly similar between the species. Subsequently, we sought to investigate if this expression was changed after a weight loss inducing bariatric procedure. By whole transcriptome analysis, we showed that upper gastrointestinal tissue expression of genes associated with nutrient sensing was hardly changed. In contrast, a considerable reduction in inflammatory pathways was observed.

Next, we sought to investigate the effects of the non-caloric sweetener rebaudioside A. This Stevia rebaudiana-derived compound was approved on the European market in 2011. As there is still some controversy about the effects of sweeteners in general on GLP-1 release, we investigated the effects of this specific sweetener. Because of the short half-life of GLP-1, the effect of nutrient stimulation was mainly studied in ex vivo and in vitro models in which local intestinal hormone release could be determined. A two dimensional gut model using intestinal organoids derived from murine intestinal crypts was developed to study location-specific hormone secretion. Rebaudioside A was found to induce GLP-1 and PYY release ex vivo from porcine intestinal tissue and in two dimensional organoids. This induction of the release was specific for the intestinal location, with the ileum being most potently stimulated by rebaudioside A. Moreover, prolonged exposure to rebaudioside A increased enteroendocrine cell numbers in two dimensional organoids. When studying the underlying mechanism in enteroendocrine STC-1 cells, we concluded that rebaudioside A-induced GLP-1 release was independent of the sweet taste receptor.

The studies presented in this thesis add to our understanding the role of receptors and other molecular structures that are likely to be involved in nutrient sensing and the modulation of gut hormone release. What we know now is that several factors play a role in gut hormone release. This includes not only the nature and dose of the active compound(s), but also the location and timing of its (their) interactions with receptors and other targets along the gastrointestinal tract. We have shown that rebaudioside A may be a potential compound to induce gut hormone release in vivo, especially when applied to the distal small intestine. Therefore, rebaudioside A may be a promising compound to influence food intake, possibly most potent when delivered in the ileum.

Small intestinal targets involved in food intake regulation : 'from nutrient to satiety signal'
Ripken, D. - \ 2016
University. Promotor(en): Renger Witkamp; H.F.J. Hendriks. - Wageningen : Wageningen University - ISBN 9789462576438 - 180 p.
obesity - preventive nutrition - small intestine - ileum - duodenum - jejunum - satiety - appetite control - food intake - safflower oil - vagus nerve - casein - stevia rebaudiana - sucrose - macronutrients - serotonin - animal models - human feeding - obesitas - preventieve voeding - dunne darm - verzadigdheid - eetlustcontrole - voedselopname - saffloerolie - nervus vagus - caseïne - macronutriënten - serotonine - diermodellen - humane voeding

Background and aim: The worldwide increasing prevalence of overweight and obesity raises concerns for health. There is a clear need for preventive strategies, because current preventative interventions have proven to be unsuccessful in the long term. New strategies may be developed based on targets in the small intestine by activating satiety signals. The thesis aimed to investigate small intestinal targets contributing to food intake regulation. These targets included serotonin, the vagal nerve and the intestinal brake mechanism.

Methods: The effects of ileal stimulation with safflower oil (lipid mixture), casein (protein), sucrose (carbohydrate) and rebaudioside A (non-caloric sweetener) on GLP-1 and PYY release were investigated by applying an porcine ex vivo intestinal segment model. The same model was also used to investigate if serotonin is involved in (non-)nutritional-induced GLP-1 and PYY release.

The contribution to satiation of GLP-1 and CCK receptors at the vagal nerve, was studied by investigating the effects of GLP-1 and CCK receptor antagonists on ad libitum food intake in a pig model of subdiaphragmatic vagotomy.

Two placebo controlled randomized crossover studies were performed in healthy volunteers to investigate the effects of small intestinal macronutrient delivery on ad libitum food intake and satiety signals. The first study compared the effects of duodenal, jejunal and ileal casein delivery on ad libitum food intake and satiety signals. The second study investigated if ileal delivery of all three macronutrients results in activation of satiety signals and reduction in ad libitum food intake. In addition, it was investigated if ileal delivery of native casein is efficiently digested and absorbed and does not result in adverse effects. In both studies the nutrients were delivered to the small intestine by inserting a nasointestinal feeding tube in healthy volunteers.

Results: All macronutrients and rebaudioside A stimulated GLP-1 and PYY release from ileal tissue segments. Protein and fat stimulated serotonin release. Inhibiting the reuptake of serotonin resulted in enhanced nutrient induced GLP-1, PYY and CCK release. Serotonin stimulated GLP-1 release from enteroendocrine cells via a serotonin receptor mediated process.

Results of the in vivo pig study showed that antagonism of the CCK receptor increased food intake in both vagotomized and sham operated pigs. Blocking the GLP-1 receptor did not affect food intake in both groups.

The human studies showed that ileal protein delivery inhibited food intake and activated satiety signals as compared to duodenal or jejunal protein delivery. Also, ileal delivery of small quantities (51.7 kcal) of each macronutrient decreased food intake and activated satiety signals. In addition, it was shown that ileal delivery of native casein resulted in a time and concentration depended increase in plasma concentrations of amino acids and did not result in activation of immune responses nor in gastrointestinal complaints.

Conclusions: The data presented in this thesis show that ileal delivery of all macronutrients results in activation of satiety signals and reduction of food intake. Stimulation of the ileum resulted in the strongest activation of satiety signals and inhibition of food intake compared to duodenal and jejunal stimulation. Besides direct nutrient-receptor interaction, the ileum senses (non-)nutritional stimuli via serotonin mediated processes resulting in GLP-1 release. In conclusion, these results demonstrate that targeting the ileum with small amounts of macronutrients is safe and has potential as a weight management strategy.

Human nutrition : a crunchy bite
Kok, F.J. - \ 2015
Wageningen : Wageningen University - ISBN 9789462573703 - 28 p.
obesity - malnutrition - infant nutrition - nutrition and health - nutrition research - human nutrition research - vitamins - aging - pregnancy - abdominal fat - body fat - obesitas - slechte voeding - zuigelingenvoeding - voeding en gezondheid - voedingsonderzoek - voedingsonderzoek bij de mens - vitaminen - verouderen - zwangerschap - buikvet - lichaamsvet
Farewell address upon retiring as Professor of Nutrition and Health
at Wageningen University on 15 October 2015
Hoe kun je te dik en toch gezond zijn?
Witkamp, R.F. - \ 2015
Universiteit van Nederland
overgewicht - lichaamsgewicht - quetelet index - obesitas - gezondheid - volksgezondheid - buikvet - lichaamsvet - fysiologie - overweight - body weight - body mass index - obesity - health - public health - abdominal fat - body fat - physiology
Je kijkt naar beneden en ziet dat er zich in de loop der jaren wat vet is gaan ophopen rondom je middel. Waarom is het gevaarlijk om juist daar teveel vet te hebben? Renger Witkamp (Wageningen UR) legt uit hoe het nu precies zit met de gevaren van die extra kilootjes en of het per definitie ongezond is om wat dikker te zijn.
Overweight and obesity in primary-school children: a surveillance system for policy-making in Europe from 2007 onwards
Wijnhoven, T.M.A. - \ 2015
University. Promotor(en): Pieter van 't Veer, co-promotor(en): Joop van Raaij. - Wageningen - ISBN 9789462574656 - 265
overgewicht - obesitas - quetelet index - lichaamsgewicht - schoolkinderen - kinderen - kwantitatieve analyse - who - gezondheid van kinderen - risicoschatting - kindervoeding - lichamelijke activiteit - kleding - overweight - obesity - body mass index - body weight - school children - children - quantitative analysis - child health - risk assessment - child nutrition - physical activity - clothing

Trudy M.A. Wijnhoven

Overweight and obesity in primary-school children: a surveillance system for policy-making in Europe from 2007 onwards.

Background

As a follow-up to the European Ministerial Conference on Counteracting Obesity convened in 2006 in Turkey, the European Childhood Obesity Surveillance Initiative (COSI) was launched by the Regional Office for Europe of the World Health Organization (WHO). COSI, a collaboration between WHO and interested Member States, aims to monitor the magnitude of overweight and obesity among primary-school children in European countries, to allow intercountry comparisons and to identify regional differences for informed policy-making. It collects at regular intervals data on weight and height of primary-school children and on their nutrition and physical activity behaviours, as well as on school environmental characteristics supportive to healthy nutrition and physical activity.

Methods

The research described in this PhD thesis is based on the data collected in the first two COSI rounds by 12 European countries in school year 2007/2008 and by 13 European countries in school year 2009/2010. Nationally representative samples of children aged 6–9 years were drawn, whereby a majority of the countries applied a two-stage school-based cluster sampling approach.

A total of 168 832 children in school year 2007/2008 and 224 920 children in school year 2009/2010 were included in the anthropometric intercountry data analyses. Children's weight and height were measured by trained examiners using standardized procedures. Participating countries were allowed to adhere to their local legal requirements by specified deviations from standardized procedures, such as in types of clothing worn by the children during weight and height measurements. For each country, the prevalence of overweight and obesity, as well as mean Z-scores of anthropometric indices of height, weight and body mass index (BMI) were computed.

The characteristics included in the analyses on the school environment referred to the frequency of physical education lessons, the availability of school playgrounds, the possibility to obtain food items and beverages on the school premises, and the organization of school initiatives to promote a healthy lifestyle. The school form was usually completed by the school principal or the teachers involved with the sampled classes. Data from 1831 schools in school year 2007/2008 and from 2045 schools in school year 2009/2010 were used. For each school, a school nutrition environment score (range: 0–1) was determined whereby higher scores correspond to higher support for a healthy school nutrition environment and the mean of the children's BMI-for-age Z-scores calculated.

Five countries in school year 2007/2008 provided children's data on 13 health-risk behaviours related to breakfast and food consumption frequency, physical activity, screen time and sleep duration (n = 15 643). These data were reported by the caregivers alone or jointly with their child. For each country, the prevalence of the risk behaviours was estimated, and associations between them and overweight and obesity examined by multilevel logistic regression analyses.

Results

In both school years, a wide range in overweight and obesity prevalence estimates was found that differed significantly by country, as well as by European region. In all countries, the percentage of overweight children was about 20% or more (range: 18–57%), and the percentage of obese children was 5% or more (range: 5–31%). The findings suggest the presence of a north–south gradient with the highest overweight and obesity prevalence estimates found in southern European countries. Furthermore, changes in mean BMI-for-age Z-scores (range: from –0.21 to +0.14) and prevalence of overweight (range: from –9.0% to +6.2%) from school year 2007/2008 to school year 2009/2010 varied significantly among countries, whereas a period of two years is considered too short to identify these developments. The clothes-adjusted overweight prevalence estimates were lower by as much as 12% than the unadjusted estimates. Monthly BMI-for-age Z-score values within countries did not show systematic seasonal effects.

Large between-country differences were observed in both school years in the availability of food items or beverages on the school premises (e.g., fresh fruit could be obtained in 12–95% of schools) and in the organization of initiatives to promote a healthy lifestyle in the selected classes (range: 42–97%). The provision of physical education lessons and the availability of school playgrounds were more uniformly present across the countries (range: 76–100%). A large variation was also seen in school nutrition environment scores (range: 0.30–0.93) whereby countries with a low score (< 0.70) graded less than three out of five characteristics as supportive. High-score countries showed more often than low-score countries a combined absence of cold drinks containing sugar, sweet snacks and salted snacks on the school premises.

The prevalence of all 13 health-risk behaviours differed significantly across countries. For instance, the percentage of children who ate ‘foods like candy bars or chocolate’ > 3 days/week ranged from 2.2% to 63.4%; this figure ranged from 1.1% to 46.5% for those who ate ‘foods like potato chips (crisps), corn chips, popcorn or peanuts’ > 3 days/week. The range for children who did not have breakfast every day was between 4.4% and 32.5%, and from 4.8% to 35.0% for those who did not play outside ≥ 1 hour/day. Not having breakfast daily and spending screen time ≥ 2 hours/day were clearly positively associated with obesity. The same was true for eating ‘foods like pizza, French fries, hamburgers, sausages or meat pies’ > 3 days/week and playing outside < 1 hour/day. While a combination of multiple less favourable physical activity behaviours was clearly positively associated with obesity, a combination of the presence of multiple unhealthy eating behaviours did not lead to higher odds of obesity.

Conclusions

The results found in both COSI school years show that overweight and obesity among 6–9-year-old children are a serious public health concern, especially in southern European countries, and show the need for accelerated efforts to prevent excess body weight early in life by all participating countries. It was possible to detect relevant changes within a period of two years but to identify clear trends within countries, a longer time interval is necessary. The data on the school nutrition environment and the children's health-risk behaviours may assist policy-makers in monitoring their national policies targeting school settings and childhood obesity. In particular, promoting physical activity-related and discouraging sedentary behaviours among schoolchildren in the context of obesity preventive interventions seem to be essential.

Aantafel! helpt tegen kinderobesitas
Ramaker, R. ; Hoek, E. van - \ 2015
Resource: nieuwssite voor studenten en medewerkers van Wageningen UR (2015). - ISSN 1389-7756
overgewicht - obesitas - kinderen - gezondheid van kinderen - voeding en gezondheid - programmaeffectiviteit - gezondheidsbevordering - gezondheidsprogramma's - overweight - obesity - children - child health - nutrition and health - program effectiveness - health promotion - health programs
Steeds vaker komt overgewicht voor bij kinderen. Doelgroepen bereiken is grote uitdaging.
The double burden of malnutrition: obesity and iron deficiency
Cepeda López, A.C. - \ 2015
University. Promotor(en): Michael Zimmermann, co-promotor(en): Alida Melse-Boonstra; I. Herter Aeberli; S. Osendarp. - Wageningen : Wageningen University - ISBN 9789462574465 - 158
obesitas - overgewicht - ijzergebrekanemie - gebreksziekten - slechte voeding - ontsteking - ijzerabsorptie - ascorbinezuren - ascorbinezuur - vrouwen - kinderen - kindervoeding - bloedvolume - mens - obesity - overweight - iron deficiency anaemia - deficiency diseases - malnutrition - inflammation - iron absorption - ascorbic acids - ascorbic acid - women - children - child nutrition - blood volume - man

Background: The world faces a “double burden” of malnutrition; this is true especially in transition countries like Mexico. The co-existence of obesity and iron deficiency (ID) within a person has been clearly demonstrated in several studies but the mechanisms linking them remain largely unknown.

Objectives: To investigate possible mechanisms that link obesity and iron status through the following specific objectives: a) reviewing the existing literature; b) investigating the coexistence of obesity and iron deficiency at the national level in Mexico; c) assessing and comparing iron absorption and blood volume (BV) in healthy, non-anemic women from different body mass index (BMI) categories, and evaluating if ascorbic acid improves iron absorption in overweight (OW) and obese (OB) women; d) evaluating if differences in BV explains reduced iron status in OW/OB women; and e) evaluating whether fat loss in obese subjects decreases inflammation and serum hepcidin and thereby improves iron absorption.

Methods: a) A literature review was conducted using Google Scholar and PubMed search engines; b) data from the 1999 Mexican Nutrition Survey, which included 1174 children (aged 5–12 y) and 621 nonpregnant women (aged 18–50 y), was used to assess the relationship between BMI, dietary iron, and dietary factors affecting iron bioavailability, iron status, and inflammation; c & d) healthy, non-anemic Swiss women (n=62) (BMI 18.5-39.9 kg/m2) consumed a stable-isotope labelled wheat-based test meal, without (-AA) and with (+AA) 31.4 mg ascorbic acid. We measured iron absorption, body composition by dual energy X-ray absorptiometry (DXA), blood volume by carbon monoxide (CO)-rebreathing method, iron status, inflammation and serum hepcidin; e) We performed a 6-month, prospective study in OB (BMI, ≥35<45 kg/m2) adults from Mexico (n=..), who had recently undergone laparoscopic sleeve-gastrectomy (LSG). At 2 months and 8 months post-LSG, subjects consumed a test drink with 6mg 57Fe as ferrous sulfate and were intravenously infused with 100 μg 58Fe as iron citrate and we measured body composition by DXA, iron status, hepcidin and inflammation.

Results: a) Obesity-related subclinical inflammation and its effects on hepcidin levels seem to be the most plausible explanation for the link between ID and obesity; b) the risk of iron deficiency in OB women and children was 2-4 times that of normal-weight individuals at similar dietary iron intakes. In addition, we found that C-reactive protein but not iron intake was a strong negative predictor of iron status, independently of BMI (P < 0.05); c) dietary iron absorption was lower in OW/OB versus normal weight subjects (Geometric mean (95%CI): 12.9 (9.7, 16.9)%) vs 19.0 (15.2, 23.5)%, P=0.049). Moreover, the enhancing effect of ascorbic acid on iron absorption in overweight/obese (28%) was only half that in normal weight women (56%); d) OW/OB women presented higher absolute blood volume and lower serum iron compared to the normal weight group. BV (r2=0.22, β=-0.29, P=0.02) was a negative predictor for serum iron when adjusted for body iron stores. We developed an equation to calculate BV in OW and OB women considering weight, height and lean body mass; e) Fat loss lead to a reduction of inflammation (Interleukin-6) and hepcidin concentrations. In iron-deficient subjects (n=17), iron absorption significantly increased after fat loss (Geometric mean (95%CI): 9.7% (6.5-14.6) to 12.4% (7.7-20.1) (P=0.03), while in iron sufficient subjects (n=21), it did not change (Geometric mean (95%CI): 5.9% (4.0-8.6) and 5.6% (3.9-8.2)) (P=0.81)).

Conclusion: Increased hepcidin concentrations, along with subclinical inflammation, limits dietary iron absorption in subjects with excessive body fat, especially in iron deficient individuals. Due to a dilutional effect of blood volume, ‘true’ hypoferremia might be overestimated in populations with a high prevalence of obesity when using serum iron as an indicator. OW/OB individuals may require: higher dietary iron intake combined with iron absorption enhancers to keep their iron status in balance; and a reduction of the obesity-related inflammatory process in order to ensure adequate iron absorption.

Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.