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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Systematic Review of Observational Studies with Dose-Response Meta-Analysis between Folate Intake and Status Biomarkers in Adults and the Elderly
Novaković, Romana ; Geelen, Anouk ; Ristić-Medić, Danijela ; Nikolić, Marina ; Souverein, Olga W. ; McNulty, Helene ; Duffy, Maresa ; Hoey, Leane ; Dullemeijer, Carla ; Renkema, Jacoba M.S. ; Gurinović, Mirjana ; Glibetić, Marija ; Groot, Lisette C.P.G.M. de; ’t Veer, Pieter van - \ 2018
Annals of Nutrition & Metabolism 73 (2018)1. - ISSN 0250-6807 - p. 30 - 43.
Adults-elderly - Dose-response - Folate - Intake-status

Background: Dietary reference values for folate intake vary widely across Europe. Methods: MEDLINE and Embase through November 2016 were searched for data on the association between folate intake and biomarkers (serum/plasma folate, red blood cell [RBC] folate, plasma homocysteine) from observational studies in healthy adults and elderly. The regression coefficient of biomarkers on intake (β) was extracted from each study, and the overall and stratified pooled β and SE (β) were obtained by random effects meta-analysis on a double log scale. These dose-response estimates may be used to derive folate intake reference values. Results: For every doubling in folate intake, the changes in serum/plasma folate, RBC folate and plasma homocysteine were +22, +21, and –16% respectively. The overall pooled regression coefficients were β = 0.29 (95% CI 0.21–0.37) for serum/plasma folate (26 estimates from 17 studies), β = 0.28 (95% CI 0.21–0.36) for RBC (13 estimates from 11 studies), and β = –0.21 (95% CI –0.31 to –0.11) for plasma homocysteine (10 estimates from 6 studies). Conclusion: These estimates along with those from randomized controlled trials can be used for underpinning dietary recommendations for folate in adults and elderly.

Use of peer reviewed articles in a MOOC : OpenScience blog
Renkema, J.M.S. - \ 2017
Wageningen University & Research
The Library for Learning: One search environment for education resources
Renkema, J.M.S. - \ 2016
Wageningen : OpenScience blog Wageningen University & Research
Open access is more than free access
Renkema, J.M.S. - \ 2016
Wageningen : OpenScience blog Wageningen University & Research
Dietary supplement use and colorectal cancer risk: A systematic review and meta-analyses of prospective cohort studies
Heine-Bröring, R.C. ; Winkels, R.M. ; Renkema, J.M.S. ; Kragt, L. ; Orten-Luiten, A.C.B. van; Tigchelaar, E.F. ; Chan, D.S.M. ; Norat, T. ; Kampman, E. - \ 2015
International Journal of Cancer 136 (2015)10. - ISSN 0020-7136 - p. 2388 - 2401.
beta-carotene supplementation - base-line characteristics - iowa womens health - combined folic-acid - colon-cancer - vitamin-d - multivitamin use - united-states - life-style - randomized-trial
Use of dietary supplements is rising in countries where colorectal cancer is prevalent. We conducted a systematic literature review and meta-analyses of prospective cohort studies on dietary supplement use and colorectal cancer risk. We identified relevant studies in Medline, Embase and Cochrane up to January 2013. Original and peer-reviewed papers on dietary supplement use and colorectal cancer, colon cancer, or rectal cancer incidence were included. “Use-no use”(U-NU), “highest-lowest”(H-L) and “dose-response”(DR) meta-analyses were performed. Random-effects models were used to estimate summary estimates. In total, 24 papers were included in the meta-analyses. We observed inverse associations for colorectal cancer risk and multivitamin (U-NU: RR¿=¿0.92; 95% CI: 0.87,0.97) and calcium supplements (U-NU: RR¿=¿0.86; 95% CI: 0.79,0.95; H-L: RR¿=¿0.80; 95% CI: 0.70,0.92; DR: for an increase of 100 mg/day, RR¿=¿0.96; 95% CI: 0.94,0.99). Inconsistent associations were found for colon cancer risk and supplemental vitamin A and vitamin C, and for colorectal cancer risk and supplemental vitamin D, vitamin E, garlic and folic acid. Meta-analyses of observational studies suggest a beneficial role for multivitamins and calcium supplements on colorectal cancer risk, while the association with other supplements and colorectal cancer risk is inconsistent. Residual confounding of lifestyle factors might be present. Before recommendations can be made, an extensive assessment of dietary supplement use and a better understanding of underlying mechanisms is needed.
Financial aspects of veterinary herd health management programmes
Ifende, V.I. ; Derks, M. ; Hooijer, G.A. ; Hogeveen, H. - \ 2014
Veterinary Record 175 (2014)9. - ISSN 0042-4900
dutch dairy farms - netherlands - mastitis - cattle - cows - objectives - diseases - model
Veterinary herd health management (VHHM) programmes are meant to support herd health and farmers’ income (Brand and Guard 1996). They were introduced in the Netherlands in the 1970s (Sol and Renkema 1984) and at present many veterinarians provide them to farmers. VHHM comprises a basic structure of goal setting, planning, execution and evaluation. Farms are visited every four to six weeks, where the veterinarian inspects the animals, evaluates gathered data and provides advice (Brand and Guard 1996). Ideally, VHHM combines animal health, food safety, animal welfare and public health with farm management and economics (Noordhuizen and Wentink 2001, LeBlanc and others 2006). VHHM programmes are used not only in the Netherlands, but on a wider scale, for instance in the UK (Wassell and Esslemont 1992) and Denmark (Kristensen and Enevoldsen 2008). The farmers in Europe have to produce under strict, often expensive and laborious, regulations while competing with commercial farmers outside the EU who are not subjected to the same rules (Cannas de Silva and others 2006). As dairy farmers strive for further efficiency in production, driven by market economics, the risks and consequences of poor health and suboptimal production increase (Sibley 2006). VHHM programmes are meant to help farmers to produce products of high quality for a low cost price (Brand and Guard 1996). Its primary objectives include the optimisation of herd health, productivity, quality of products and profitability of the dairy enterprise (Blood and others 1978). In practice, some farms or veterinarians embrace the concepts of VHHM by active participation, while others do not (Derks and others 2012). Also, veterinarians are not always able to meet farmers’ requirements for VHHM (Hall and Wapenaar 2012, Derks 2013). Its efficiency is hard to determine. There is, for instance, no recent information on the cost implications of this programme with regard to perceived profitability in farms. A limited number of controlled studies were carried out in the early 1970s and 1980s to evaluate the effects of VHHM on farm performance (Williamson 1980, Sol and others 1984). It was shown that a VHHM programme produced considerable benefits to participating farmers. A follow-up study showed approximately 8 per cent increase in margin per cow compared with the initial margin, using 1974–1975 as a base year (Hogeveen and others 1992). Since that time, no economic studies were carried out on the effects of these programmes. This study evaluates the economic relationship between participation in a VHHM programme and farm performance on dairy farms and estimates the costs incurred by the participation in this programme as well as the net returns (NR), including factors that influence the NR on a farm.
Endnote X7
Brouwer, J.H.D. ; Renkema, J.M.S. ; Kersten, A.M.P. - \ 2014
[Wageningen] : Wageningen UR Library - 42
computer software - bibliografieën - databanken - indexeren - literatuur - publicaties - documentatie - bibliographies - databases - indexing - literature - publications - documentation
Socio-economic determinants of micronutrient intake and status in Europe: a systematic review
Novakovic, R.N. ; Cavelaars, A.J.E.M. ; Geelen, A. ; Nikolic, M. ; Altaba, I.I. ; Vinas, B.R. ; Ngo, J. ; Golsorkhi, M. ; Medina, M. ; Brzozowska, A. ; Szczecinkska, A. ; Cock, D. de; Vansant, G. ; Renkema, J.M.S. ; Serra Majem, L. ; Moreno, L.A. ; Glibetic, M. ; Gurinovic, M. ; Veer, P. van 't; Groot, C.P.G.M. de - \ 2014
Public Health Nutrition 17 (2014)5. - ISSN 1368-9800 - p. 1031 - 1045.
life-style factors - food-habits - dietary-intake - maternal education - nutrient intake - population - nutrition - quality - adults - consumption
OBJECTIVE: To provide the evidence base for targeted nutrition policies to reduce the risk of micronutrient/diet-related diseases among disadvantaged populations in Europe, by focusing on: folate, vitamin B12, Fe, Zn and iodine for intake and status; and vitamin C, vitamin D, Ca, Se and Cu for intake. DESIGN: MEDLINE and Embase databases were searched to collect original studies that: (i) were published from 1990 to 2011; (ii) involved >100 subjects; (iii) had assessed dietary intake at the individual level; and/or (iv) included best practice biomarkers reflecting micronutrient status. We estimated relative differences in mean micronutrient intake and/or status between the lowest and highest socio-economic groups to: (i) evaluate variation in intake and status between socio-economic groups; and (ii) report on data availability. SETTING: Europe. SUBJECTS: Children, adults and elderly. RESULTS: Data from eighteen publications originating primarily from Western Europe showed that there is a positive association between indicators of socio-economic status and micronutrient intake and/or status. The largest differences were observed for intake of vitamin C in eleven out of twelve studies (5-47 %) and for vitamin D in total of four studies (4-31 %). CONCLUSIONS: The positive association observed between micronutrient intake and socio-economic status should complement existing evidence on socio-economic inequalities in diet-related diseases among disadvantaged populations in Europe. These findings could provide clues for further research and have implications for public health policy aimed at improving the intake of micronutrients and diet-related diseases
Systematic review: socioeconomic and cultural determinants of low micronutrient intake and status within EURRECA network.
Novakovic, R. ; Cavelaars, A. ; Renkema, M. ; Ngo, J. ; Vinas, B.R. ; Golsorkhi, M. ; Wharton Medina, M. ; Brzozowska, A. ; Szczecinska, A. ; Iglesia, I. ; Geelen, A. ; Cock, D. de; Veer, P. van 't; Groot, C.P.G.M. de; Serra Majem, L. ; Nikolic, M. ; Moreno, L.A. ; Matthys, C. ; Glibetic, M. - \ 2011
Bibliometrics in the library, putting science into practice
Gerritsma, W. ; Loman, M.E. ; Renkema, J.M.S. ; Togt, P.L. van der; Veerman, I.V. ; Veller, M.G.P. van - \ 2010
In: 11th International conference on science and technology indicators "creating value for users", Leiden, 9-11 September 2010. - - p. 98 - 99.
Nutri-RecQuest: a web-based search engine on current micronutrient recommendations
Cavelaars, A.J.E.M. ; Kadvan, A. ; Doets, E.L. ; Tepsic, J. ; Novakovic, R.N. ; Dhonukshe-Rutten, R.A.M. ; Renkema, M. ; Glibetic, M. ; Bucchini, L. ; Matthys, C. ; Smith, R. ; Veer, P. van 't; Groot, C.P.G.M. de; Gurinovic, M. - \ 2010
European Journal of Clinical Nutrition 64 (2010)S2. - ISSN 0954-3007 - p. S43 - S47.
Background: The EURRECA (EURopean micronutrient RECommendations Aligned) Network of Excellence collated current micronutrient recommendations. A user-friendly tool, Nutri-RecQuest, was developed to allow access to the collated data and to create a database source for use in other nutritional software tools. Methods: Recommendations, that is, intakes of micronutrients sufficient to meet the requirements of the majority of healthy individuals of that population, from 37 European countries/organizations and eight key non-European countries/regions comprising 29 micronutrients were entered into a database. General information on the source of the recommendations, as well scientific background information, was added. Results: A user-friendly web-based interface was developed to provide efficient search, comparison, display, print and export functions. Conclusion: Easy access to existing recommendations through the web-based tool may be valuable for bodies responsible for setting recommendations, as well as for users of recommendations including scientists, policy makers, health professionals and industry. Adding related dietary reference values such as average nutrient requirements and upper limits may extend the utility of the tool
Fish consumption, n-3 fatty acids and colorectal cancer: a meta-analysis of prospective cohort studies
Schouten, J.M. ; Kamphuis, C. ; Stam, B.E. ; Burema, J. ; Renkema, J.M.S. ; Bakker, E.J. ; Veer, P. van 't; Kampman, E. - \ 2007
Fish Consumption, n-3 Fatty Acids, and Colorectal Cancer: A Meta-Analysis of Prospective Cohort Studies
Geelen, A. ; Schouten, J.M. ; Kamphuis, C. ; Stam, B.E. ; Burema, J. ; Renkema, J.M.S. ; Bakker, E.J. ; Veer, P. van 't; Kampman, E. - \ 2007
American Journal of Epidemiology 166 (2007). - ISSN 0002-9262 - p. 1116 - 1125.
colon-cancer - meat consumption - dietary habits - vitamin-d - gastrointestinal cancers - singapore chinese - rectal-cancer - risk-factors - fiber intake - life-style
Animal studies show favorable effects of n-3 fatty acids on inflammation and cancer, but results from epidemiologic studies appear to be inconsistent. The authors conducted meta-analyses of prospective cohort studies that evaluated the association between fish consumption or n-3 fatty acids and colorectal cancer incidence or mortality. Random-effects models were used, and heterogeneity between study results was explored through stratified analyses. The pooled relative risks for the highest compared with the lowest fish consumption category were 0.88 (95% confidence interval: 0.78, 1.00) for colorectal cancer incidence (14 studies) and 1.02 (95% confidence interval: 0.90, 1.16) for colorectal cancer mortality (four studies). The pooled relative risks for colorectal cancer incidence were 0.96 (95% confidence interval: 0.92, 1.00) for each extra occurrence of fish consumption per week (seven studies) and 0.97 (95% confidence interval: 0.92, 1.03) for each extra 100 g of fish consumed per week (four studies). Stratified analysis showed that the pooled relative risk for colorectal cancer incidence was more pronounced for women and in studies with a large exposure contrast. In cohort studies, fish consumption was shown to slightly reduce colorectal cancer risk. Existing evidence that n-3 fatty acids inhibit colorectal carcinogenesis is in line with these results, but few data are available addressing this association.
Location-specific modeling for optimizing wildlife management on crop farms
Wenum, J.H. ; Wossink, G.A.A. ; Renkema, J.A. - \ 2004
Ecological Economics 48 (2004)4. - ISSN 0921-8009 - p. 395 - 407.
biodiversity - diversity - preservation - integration - agriculture - indicators - pollution - gis
In order to guide conservation and restoration of wildlife in agricultural areas research is needed into the trade-off between wildlife and agricultural production and income. This study presents a location-specific model for optimizing wildlife management on crop farms using integer programming. The model is applied to crop farming in the Netherlands. Most important outcome is a wildlife-cost frontier at the farm level. Model results show that rotating wildlife conservation practices across the farm is economically more attractive than fixed-location practices. Opportunities for use of the insights provided by model results by both policy makers and farmers are analyzed.
Relations between rheological properties and network structure of soy protein gels
Renkema, J.M.S. - \ 2004
Food Hydrocolloids 18 (2004)1. - ISSN 0268-005X - p. 39 - 47.
whey-protein - casein gels - beta-lactoglobulin - fractal nature - ph - conglycinin
This paper focuses on the relations between network structure and rheological properties of soy protein gels as a function of pH and ionic strength. Network structure has been characterized independently by permeability measurements and confocal scanning laser microscopy in terms of coarseness. Results showed that gels at pH 3.8 and 5.2 were coarser than at pH 7.6, except for pH 3.8–0 M NaCl. Rheological properties determined were dynamic moduli, Young's modulus, fracture stress and fracture strain. Gels at pH 3.8 had lower fracture strains and higher moduli than gels at pH 5.2 and 7.6, while fracture stresses were about the same. To relate the rheological properties to network structure in a self-consistent way, an additional structural parameter was required: curvature of the strands.
Concentration dependence of dynamic moduli of heat-induced soy protein gels
Renkema, J.M.S. ; Vliet, T. van - \ 2004
Food Hydrocolloids 18 (2004)3. - ISSN 0268-005X - p. 483 - 487.
particle gels - shear modulus - casein gels - denaturation - gelation - ph
The concentration dependence of dynamic moduli of soy protein gels was studied for different protein preparations (soy protein isolate), purified glycinin and a -conglycinin rich fraction) at various pHs and salt concentrations. The concentration dependence of the storage modulus of glycinin and -conglycinin gels was similar to that of SPI gels. For SPI, the critical protein concentration for gelation was estimated to be between 3 and 5% at pH 7.6 (0.2 M NaCl), and between 6.5 and 8% at pH 7 (0 M NaCl), and 0% at pH 5.2 and pH 3.8 (0.2 M NaCl). At the high pHs the critical protein concentration decreased with the stage in the heating cycle. Relating the experimental data to a fractal model, both rheological and permeability measurements resulted in a consistent value for the fractal dimensionality Df (=2.3) for SPI gels at pH 3.8 and 0.2 M NaCl. At pH 5.2 and 7.6 (0.2 M NaCl), and pH 7 (0 M NaCl), the concentration dependence of the modulus could not be analysed theoretically. Likely this is due to rearrangements in the spatial structure of the network starting directly after a percolating network was formed. It causes the concentration dependence to depend on ageing time.
Formation, structure and rheological properties of soy protein gels
Renkema, J.M.S. - \ 2003
Assessment of the quality of farmers environmental management and its effects on resource use efficiency: A Dutch case study
Koeijer, T.J. de; Wossink, G.A.A. ; Smit, A.B. ; Janssens, S.R.M. ; Renkema, J.A. ; Struik, P.C. - \ 2003
Agricultural Systems 78 (2003). - ISSN 0308-521X - p. 85 - 103.
technical efficiency
Most research on efficiency of farm management focuses on the relationship between an array of individual management variables and technical performance. Few studies have analysed the relationship between the total complex of farm management and technical farm performance. The present study uses the concept of strategic management and applies it to nitrogen management on Dutch arable farms. Data Envelopment Analysis (DEA) was used to assess farm specific efficiency scores for fertiliser use. For a sub-sample of the farms used in the DEA analysis, the strategic management concept was addressed by means of a workshop. The management elements (objectives, internal analysis of weaknesses and strengths, external analysis of opportunities and threats, and synthesis) were made operational by relating them to the introduction of the Mineral Accounting System (MINAS) by 2001 for Dutch arable farms. The external analysis was evaluated by questions about the MINAS rules; the internal analysis was evaluated by questions on the expected consequences for the farmer's N management. An interactive simulation model evaluating whether farmers were able to choose the optimal fertilisation strategy in view of MINAS assessed the 'quality of the synthesis'. A positive significant correlation was found between the 'quality of the synthesis' and N efficiency. (C) 2003 Elsevier Ltd. All rights reserved.
Annual variation in weather: its implications for sustainability in the case of optimising nitrogen input in sugar beet
Koeijer, T.J. de; Buck, A.J. de; Wossink, G.A.A. ; Oenema, J. ; Renkema, J.A. ; Struik, P.C. - \ 2003
European Journal of Agronomy 19 (2003). - ISSN 1161-0301 - p. 251 - 264.
damage control - agricultural production - fertilizer application - netherlands 1948-1989 - vonliebig - model - crop - econometrics - efficiency - indexes
Efficient crop husbandry is crucial in order to prevent unnecessary emissions of environmentally damaging inputs and to maintain economic soundness, but it raises the question of which productivity and efficiency levels should be realised. Agronomists and economists are still debating this issue, as they base their insights on different production functions: economists assume decreasing returns of input use, whereas the response curve used by agronomists is often described as linear with a plateau (LRP). The first objective of this paper is to reconcile these points of view by showing that due to annual variation in weather individual LRP curves turn into a concave function with decreasing returns when aggregated. The second objective is to present empirical evidence on the impact of weather variation on optimal input levels for the case of nitrogen in sugar beet in The Netherlands. Two methods were used: bio-physical simulation and estimation with a regression model using panel data. Optimal crop growth and nitrogen input were simulated with the Water and Agro-chemicals in the soil and Vadose Environment (WAVE) model, using weather data for 43 years. Parameters were assessed with and without additional weather effects. An agronomic crop growth simulation model such as WAVE might underestimate the effect of variation in weather on the agronomic efficiency of nitrogen, because pests, weeds and diseases as well as the effectiveness of biocides, the sowing date and possible harvesting problems are strongly influenced by the weather. To test for this effect, weather indexes that include these indirect weather effects on the occurrence of pests and diseases were derived from panel data by means of a regression model. These weather indexes were used to re-assess the impact of weather variability on the agronomic efficiency of nitrogen in sugar beet cropping. The results of the bio-physical simulation showed that due to annual variation in weather the agronomic efficiency of nitrogen use was reduced by 10% at the current ratio of prices of nitrogen and sugar beet. The variation in weather, including indirect effects, caused the agronomic efficiency to decrease by 13%. This relatively small decrease suggests that at least some of the indirect weather effects might have an opposite effect on the agronomic efficiency of nitrogen use compared with the direct weather effects. This hypothesis seems to be supported by the absence of a significant correlation between the two weather indexes and by the lower estimated variance of the weather indexes based on panel data. (C) 2002 Elsevier Science B.V. All rights reserved.
Influence of pH and Ionic Strength on Heat-Induced Formation and Rheological Properties of Soy Protein Gels in Relation to Denaturation and Their Protein Compositions
Renkema, J.M.S. ; Gruppen, H. ; Vliet, T. van - \ 2002
Journal of Agricultural and Food Chemistry 50 (2002)21. - ISSN 0021-8561 - p. 6064 - 6071.
soybean beta-conglycinin - molecular-structure - gelation - glycinin - subunits - solubility - isolate - 7s - association - behavior
The influence of pH and ionic strength on gel formation and gel properties of soy protein isolate (SPI) in relation to denaturation and protein aggregation/precipitation was studied. Denaturation proved to be a prerequisite for gel formation under all conditions of pH and ionic strength studied. Gels exhibited a low stiffness at pH >6 and a high stiffness at pH 5 less protein and especially fewer acidic polypeptides take part in the network, coinciding with less stiff gels. At pH 7.6, extensive rearrangements in the network structure took place during prolonged heating, whereas at pH 3.8 rearrangements did not occur.
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