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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Validation of ISO 17586 soil quality : extraction of trace elements using dilute nitric acid
Vark, W. van; Harmsen, J. - \ 2016
Alterra, Wageningen-UR (Alterra-rapport 2693) - 55 p.
soil - soil quality - trace elements - standards - bioavailability - iso - extraction - bodem - bodemkwaliteit - sporenelementen - normen - biologische beschikbaarheid - extractie
Aparte toediening geeft betere resultaten : alternatief voor ijzerchelaat in praktijk getoetst met positief resultaat
Hoogstraten, K. van; Voogt, W. - \ 2015
Onder Glas 12 (2015)5. - p. 23 - 25.
glastuinbouw - plantenvoeding - sporenelementen - polyfosfaten - bemesting - toepassing - opname (uptake) - effecten - ijzerhoudende meststoffen - chelaten - meststofdragers - greenhouse horticulture - plant nutrition - trace elements - polyphosphates - fertilizer application - application - uptake - effects - iron fertilizers - chelates - fertilizer carriers
IJzer is een onmisbaar voedingselement, dat nodig is voor de vorming van bladgroen en zo chlorose voorkomt. Omdat het element normaal niet opgelost blijft – en dan niet beschikbaar is voor de plant – zijn al jaren ijzerchelaten voorhanden. Bij een nieuwe meststof is het ijzer op een andere manier gebonden, namelijk met een combinatie van polyfosfaten. Bij toediening via een aparte bak blijkt het in de praktijk goed te werken. De meststof heeft daarnaast andere effecten, zoals minder bladrand en makkelijker UV-ontsmetting. Recent onderzoek en praktijkervaringen geven vergelijkbare resultaten.
Evaluation of dietary diversity scores to assess nutrient adequacy among rural Kenyan women
Ngala, S.A. - \ 2015
University. Promotor(en): Frans Kok, co-promotor(en): Inge Brouwer; A.M. Mwangi. - Wageningen : Wageningen University - ISBN 9789462574236 - 149
kenya - gezondheid van vrouwen - voedingsstoffen - sporenelementen - voedingsgeschiktheid - diversiteit - plattelandsbevolking - kwantitatieve methoden - kwalitatieve methoden - women's health - nutrients - trace elements - nutritional adequacy - diversity - rural population - quantitative methods - qualitative methods

Evaluation of dietary diversity scores to assess nutrient adequacy among rural Kenya women

S. A. Ngala

Abstract

Background:The major cause of micronutrient deficiencies are low intake due to monotonous diets, especially among women of child bearing age. Dietary diversity score has been found to be a good proxy indicator for micronutrient adequacy. However, there are still outstanding methodological questions related to seasonal effects, food intake methods, selection of foods and the cut-off for estimating the prevalence of acceptable nutrient adequacy. This thesis evaluated the performance of a simple dietary diversity score for assessing nutrient adequacy in the diets of rural women in Kenya.

Methods: The study was conducted in Mbooni Division, Makueni District, Kenya among non-pregnant, non-lactating women of reproductive age having a child between 2-5 years. Food consumption data was collected by 3 non-consecutive 24hour-recalls and a qualitative 24hour-recall in pre-harvest (period 1, October 2007, n=73) and post-harvest (period 2, April 2008, n=203) seasons. Dietary diversity scores (DDS) were derived based on 10 and 13 food groups with minimum intake threshold per food group of 0 and 15 g respectively. Mean probability of adequacy (MPA) was calculated based on intake of 11 micronutrients.

Results: The dietary diversity score (DDS) and mean probability of adequacy (MPA) were significantly but moderately associated in both seasons (r=0.40 and r=0.38 period 1 and 2) and the association was independent of season (p=0.45). The DDS from a qualitative 24 hour recall (DDSql) showed little agreement with quantitative 24 hour recall (DDSqn) with a mean difference (DDSqn-DDSql) of -0.51±1.46 (Period 1) and -0.58±1.43 (period 2), with lower correlation between MPA and DDS for DDSql (r=0.14 and 0.19 in period 1 and 2, p>0.05) compared to DDSqn (r=0.40 and 0.54 in period 1 and 2, p<0.01). The Informative food-based scores and the food group-based scores were moderately associated with mean probability of adequacy (r=0.54-0.59 in period 1; r=0.37- 0.45 in period 2) with higher values for informative food based scores. The Minimum Dietary Diversity of Women (MDD-W) and mean probability of adequacy were significantly but moderately associated in both seasons (r=0.43-0.58 in period 1; r=0.24-0.50 in period 2) with but the use of a cutoff of consuming 5 or more food groups as indication of nutrient adequacy resulted in high total misclassification in both periods.

Conclusion: A dietary diversity score can be used as a simple proxy for micronutrient adequacy, independent of season. The dietary diversity score derived from qualitative free-listing 24-hour recall formed a poor indicator, needing further refinement to improve its performance. The informative food-based score performs moderately better in predicting nutrient adequacy, but its advantages do not outway those of the food group-based scores, and the latter is therefore preferred. The Minimum Dietary Diversity score for Women, formed a good indicator to predict nutrient adequacy, but using the cutoff of 5 or more food groups resulted in an overestimation of prevalence of adequate intake in our resource poor population.

Speciation of trace metals and their uptake by rice in paddy soils
Pan, Y. - \ 2015
University. Promotor(en): Rob Comans, co-promotor(en): Gerwin Koopmans; J. Song. - Wageningen : Wageningen University - ISBN 9789462572744
oryza sativa - rijst - padigronden - sporenelementen - voedingsstoffenopname (planten) - bodemchemie - natte rijst - oplosbaarheid - rice - paddy soils - trace elements - nutrient uptake - soil chemistry - flooded rice - solubility

Rice (Oryza sativa L.) is the most important staple food in South and Southeast Asia and plays a crucial role in food security. However, with fast urbanization and industrialization and economic growth in these parts of the world, the production and quality of rice has become an increasing concern, because contamination of paddy soils with trace metals in industrialized areas can lead to yield reduction of rice, a decline in the nutritional quality of the rice, and an accumulation of trace metals in rice grains. In this PhD thesis, I used a combination of experimental research and mechanistic modeling to investigate the solubility of trace metals in paddy soils exposed to alternating flooding and drainage conditions and to link trace metal solubility to the uptake by rice plants over time. This work contributes to the understanding of how redox chemistry affects the solubility of trace metals in flooded soil and sediment systems and provides a tool for the measurement of the free trace metal concentrations in flooded soil and sediment systems in situ in the form of the field DMT.

Voederbomen in trek
Eekeren, N.J.M. van; Luske, B.L. ; Vonk, M. ; Anssems, E. - \ 2015
V-focus 12 (2015)1. - ISSN 1574-1575 - p. 38 - 39.
melkveehouderij - geitenhouderij - schapenhouderij - melkveevoeding - geitenvoeding - schapenvoeding - bomen als veevoer - herkauwersvoeding - mineralenopname - sporenelementen - dairy farming - goat keeping - sheep farming - dairy cattle nutrition - goat feeding - sheep feeding - fodder trees - ruminant feeding - mineral uptake - trace elements
Bladeren en twijgen van bomen en struiken hebben potentie in het rantsoen van koeien, geiten en schapen, omdat ze een aanvullende bron zijn van eiwit, mineralen en sporenelementen. Daarnaast bevatten veel bomen secundaire plantenstoffen die een positief effect kunnen hebben op de vertering en de gezondheid van herkauwers. In het Praktijknetwerk Voederbomen en Functioneel Landgebruik (www.voederbomen.nl) is de inpasbaarheid van voederbomen op melkveebedrijven getest.
Elementen chloor en nikkel ook essentieel voor groei en ontwikkeling : er is meer dan hoofd- en sporenelementen
Kierkels, T. ; Heuvelink, E. - \ 2014
Onder Glas 11 (2014)5. - p. 26 - 27.
glastuinbouw - plantenvoeding - sporenelementen - metaalelementen - plantgezondheid - sporenelementtekorten - mestbehoeftebepaling - toepassing - greenhouse horticulture - plant nutrition - trace elements - metallic elements - plant health - trace element deficiencies - fertilizer requirement determination - application
Het was zo simpel: planten hebben twaalf elementen echt nodig, verdeeld in zes hoofdelementen en zes sporenelementen. Maar dat beeld kan beter op de schop. Van minstens twee elementen is aangetoond dat ook zij noodzakelijk zijn, sommige andere zijn essentieel voor bepaalde planten en nog een hele groep kan soms de groei en kwaliteit bevorderen. En zoals zo vaak: veel is nog onbekend.
Paling analyses Ecofide
Hoek-van Nieuwenhuizen, M. van - \ 2013
IJmuiden : IMARES (Rapport / IMARES Wageningen UR C196/13) - 13
palingen - european eels - representatieve monstername - monsters - chemische analyse - polychloorbifenylen - organo-tinverbindingen - vet - droge stof - sporenelementen - eels - representative sampling - samples - chemical analysis - polychlorinated biphenyls - organotin compounds - fat - dry matter - trace elements
De opdracht bestond uit het karakteriseren, fileren en homogeniseren tot een mengmonster van de door Ecofide aangeleverde set palingen; het uitvoeren van chemische analyses in het mengmonster en het rapporteren van de resultaten. Dit rapport omvat een korte omschrijving van de toegepaste methoden, een kwaliteitsparagraaf en een presentatie van de resultaten in Exceltabellen.
Development of iron and zinc enriched mungbean (Vigna radiata L.) cultivars with agronomic traits in consideration
Singh, R. - \ 2013
University. Promotor(en): Richard Visser, co-promotor(en): Sjaak van Heusden. - S.l. : s.n. - ISBN 9789461736840 - 175
vigna radiata - mungbonen (green gram) - mungbonen - sporenelementen - ijzer - zink - plantenveredeling - genetische diversiteit - voeding - india - voedselsoevereiniteit - green gram - mung beans - trace elements - iron - zinc - plant breeding - genetic diversity - nutrition - food sovereignty

Malnutrition in India, particularly among women, children and adolescents is an emergency that needs immediate attention in this fast growing and developing country. Micronutrient deficiencies are threatening public health in India more and more. Deficiencies of micronutrients drastically affect growth, metabolism and reproductive phase in humans as it does in plants and animals. Cereal and pulse based Indian diets are qualitatively deficient in micronutrients such as iron, calcium, vitamin A and zinc. This is due to a low intake of income-elastic protective foods such as pulses, vegetables, fruits, and foods of animal origin. It is presumed that if we restore the geographical connection between food production and consumption in local food networks it will help in solving this nutritional problem in India. This offers new opportunities to tailor science & technology to location specific patterns of food production and consumption, which may lead to environmentally and socially sustainable agriculture. Despite global pressure (including from science and technology) to focus agricultural cultivation on a limited number of food crops, still many so-called orphan crops like mungbean do exist and are cultivated in location-specific crop rotation systems. Particularly, the seed legumes are of major nutritional importance, especially in developing countries, because they have high protein contents of good biological value. Out of the total sales of mungbean, about half of the sales are within the village which clearly establishes the need for development of infrastructure and facilities at the village level to serve the interests of the farm households. Moreover, it is also necessary to shift the focus of development from the urban market centres (largely developed) to the rural market centres. Linking breeding, nutrition, processing and standardisation of food products, may be designed within the experimental framework of empowering poor farmers. Hence, tailoring plant, food and social sciences to empower local mungbean production and consumption patterns has been designed as an interdisciplinary program of plant breeding, food technology, human nutrition and sociology of science and technology. Thus the ‘Tailoring Food Sciences to Endogenous Patterns of Local Food Supply for Future Nutrition’ (TELFUN) project aimed to help people in selecting their own way of local food production, processing and consumption of the best suited local food. The main objective is to strengthen “The Science in Society” approach by remodeling participatory research and development and the general aim of TELFUN was to attune disciplinary research objectives within an interdisciplinary framework to enhance food sovereignty and to improve mungbean based production and consumption pattern in selected research area (Haryana, India). As an example our research focused on further improving one of the potential nutritional crops, namely mungbean. The present work emphasizes on mungbean in general and especially on the available micronutrient variation in the mungbean germplasm. The mungbean (green gram), Vigna radiata (L.) Wilczek is native to the Indian subcontinent. They are warm season annuals, highly branched and having trifoliate leaves like the other legumes. Seeds of mungbean are small, ovoid in shape, and green in color. Mungbean seeds are high in protein (21%–28%), calcium, phosphorus and certain vitamins. Moreover they are easily digested and they replace scarce animal protein in human diets in vegetarian populations of the world. The selected area of research centres contain a high level of local biodiversity and are the locations for domestication of mungbean. This legume has co-evolved with their natural ecosystems and is well-adapted to withstand the local biotic and abiotic stresses. This will help in enabling the reconnection of the cultivation of the mungbean with their natural environments. Moreover, as domestication has taken place by local farmers during many centuries, they have accumulated local endogenous knowledge, which is very relevant for local food networks (www.telfun.info). Thus to explore the potential mungbean network, the present thesis set its objectives. They were: i) identification of the major constraints, limitations and preferences of producer’s with regard to mungbean, ii) assessing the diversity in the available germplasm and assessing the effects of different environments on selected cultivars for their mineral micronutrients and iii) to make a start to develop tools for marker assisted breeding with regard to iron and zinc.

Socioeconomic differences in micronutrient intake and status in Europe
Novakovic, R.N. - \ 2013
University. Promotor(en): Pieter van 't Veer; Lisette de Groot, co-promotor(en): Anouk Geelen; M. Gurinovic. - [S.l. : S.n. - ISBN 9789461735775 - 154
sporenelementen - voedingsstoffenopname (mens en dier) - voedingstoestand - sociale economie - sociaal-economische positie - europa - vitaminen - trace elements - nutrient intake - nutritional state - socioeconomics - socioeconomic status - europe - vitamins

The aim of this thesis was to evaluate micronutrient intake and status of socioeconomic disadvantaged populations, such as from Central and Eastern European (CEE) as compared to other European populations, and low socioeconomic status (SES) groups as compared to high SES groups within European countries. We addressed the micronutrients that have been prioritized because of their relevance for nutritional health by the EC-funded EURRECA Network of Excellence. Moreover, we assessed the association between folate intake and status which can be used in the process of setting folate DRVs.

Micronutrient intake and status of CEE countries versus other European countries

CEE countries have recently experienced rising income inequalities over a period of economic transition. There is some evidence that these reforms have been accompanied by health inequalities. Inadequacy in micronutrient intake and status may contribute to these inequalities. Because in more affluent Western European countries wide ranges in micronutrient intake and status are observed, we studied if low micronutrient intake and status levels are prevailing in CEE. The findings from this thesis signal no differences in micronutrient intake and status between CEE populations in comparison to those of other European regions with the exception of calcium intake in adults and iodine status in children that were lower in CEE than in other European regions. Since data from Western Europe indicate that inadequacies do exist among SES strata, more insight in the nutritional situation of lower SES populations in CEE and an understanding of both its determinants and consequences is needed. It is important to mention that evidence from grey literature added to that from open access sources. Fundamental to further studying of nutritional health in CEE, is suitable data. We underline the necessity for conducting nutritional surveillances on micronutrient intake and status in CEE as we have identified significant knowledge gaps for many life-stage groups.

Differences in micronutrient intake between SES groups

Considering that not enough studies have addressed the relationship between SES and micronutrient intake and status in their analyses of nutritional health, we performed a systematic review on this topic and we used data from the large European EPIC cohort to address that issue.

To be able to conclude on socioeconomic, i.e. educational, occupational and income, inequalities associated with intake and status of prioritized micronutrients for all life stages in Europe, substantial knowledge gaps should be filled. Currently, data are mostly available for the intake of calcium, vitamin C and iron as collected from adults in Western European countries. When either of the above mentioned SES indicators was applied to estimate relative differences in micronutrient intake and status between the lowest and the highest SES category within one study, the results often, but not consistently, indicated a lower intake and/or status in low versus high SES groups. For example, in eight out of ten studies a lower intake for calcium intake was found with relative differences ranging from -2 to -14%. Similar patterns were found for vitamin C and iron: in eleven out of twelve studies relative differences ranged from -5 to -48% for vitamin C, whereas in nine of ten studies on iron relative differences went up to -14%. Studies on intake and/or status of folate, vitamin B12, zinc, iodine, and intake of vitamin D, selenium and copper were limited. Still, when differences were observed, it appeared that lower intake in low than in high SES groups was found except for vitamin B12 and zinc for which the findings were inconsistent.

Furthermore, using education as a proxy for SES, we assessed differences in micronutrient intake between educational levels using the individual-participant data on European adults and elderly from the EPIC cohort. Based on data from 10 Western European countries it appeared that intake of calcium (except in France and a distinctive ‘health-conscious’ group in the UK), folate (except in Greece), and vitamin C was lower in the lowest than in the highest education groups: relative differences ranged up to 12, 13 and 23%, respectively. The intake of iron differed marginally, whereas the variation in intake of vitamins D and B12 was inconsistent. The observed association between educational level and intake of micronutrients was the same for men and women. Furthermore, differences in micronutrient intake were found to be larger between countries than between SES groups.

With respect to SES differences in micronutrient intake and status, there are significant gaps in the open source literature for many life-stage groups in Europe, but particularly in CEE countries. There is a clear need for cross-country and within country comparative research and for the monitoring of trends in dietary intake across different SES groups and European countries.

Relationship between folate intake and status to add complementary evidence for deriving folate dietary reference values (DRVs)

DRVs are under continuous review and periodic revision as the cumulative evidence base and body of knowledge evolve. Folate is considered a public health priority micronutrient for which re-evaluation of DRVs is needed. For this micronutrient, a systematic review of observational studies on the relationship between intake and status was done followed by meta-analysis. The intake of folate was significantly associated with markers of folate status. The results of our meta-analysis showed that an average person with a folate intake of 100 µg/day has a serum/plasma folate status concentration that is 26% higher and a red blood cell folate status that is 21% higher than a person who has a folate intake of 50 µg/day; plasma homocysteine was found to be 16% lower. The difference between natural food folate and that from supplements and fortified foods (folic acid) significantly influenced the estimated relationship between folate intake and serum/plasma status. Associations were stronger when assessed as folate from the diet than as folate from diet and supplements. Dietary assessment method did not significantly influence the association, although pooled estimates were somewhat higher when FFQs were used as compared to 24-hour recalls combined with food records. To focus on the impact of poor intakes on related health outcomes, data modelling can be conducted to produce estimates for Average Nutrient Requirements. For this analysis datasets and statistical models developed within the EURRECA NoE are available and can be used.

Overall, further research would benefit from methodologically comparable data on food intake in all age ranges, especially on so far understudied CEE populations. Both intakes obtained through diet and from supplements and fortified foods should be assessed. Monitoring of trends across SES strata should be done with standardized SES measurements that would also facilitate cross-country comparative research. The findings on the level and distribution of micronutrient intake and status could be used for development of food based dietary guidelines. To make them effective in meeting populations’ micronutrient needs, they should be created accounting for the country specific dietary patterns giving consideration to the socioeconomic context.

Adviesbasis voor de bemesting van akkerbouwgewassen : sporenelementen
Haan, J.J. de; Geel, W.C.A. van - \ 2013
Kennisakker.nl 2013 (2013)20 maart.
akkerbouw - gewassen - mest - sporenelementen - borium - mangaan - koper - ijzer - zink - molybdeen - toepassing - dosering - bemesting - arable farming - crops - manures - trace elements - boron - manganese - copper - iron - zinc - molybdenum - application - dosage - fertilizer application
In dit artikel worden adviezen gegeven voor de bemesting van akkerbouwgewassen met de sporenelementen; borium, mangaan, koper, ijzer, zink en molybdeen.
Verkenning mogelijke schaarste aan micronutriënten in het voedselsysteem
Chardon, W.J. ; Oenema, O. - \ 2013
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2413) - 43
bodemchemie - bemesting - mineralen - sporenelementen - kringlopen - borium - kobalt - koper - molybdeen - selenium - zink - schaarste - akkerbouw - tuinbouw - soil chemistry - fertilizer application - minerals - trace elements - cycling - boron - cobalt - copper - molybdenum - zinc - scarcity - arable farming - horticulture
Onder een micro-nutriënt wordt verstaan: een element dat essentieel is voor de groei en het functioneren van de plant, een dier of de mens, maar waarvan de benodigde hoeveelheid relatief klein is. In dit rapport zijn zes elementen geselecteerd omdat zij aantoonbaar essentieel zijn voor meerdere soorten gewassen of voor de veehouderij, en omdat de mate van vóórkomen in de aardkorst relatief gering is, waardoor (toekomstige) mondiale schaarste denkbaar is. Deze elementen zijn resp. borium, kobalt, koper, molybdeen, seleen en zink (B, Co, Cu, Mo, Se, en Zn). Alleen voor B en Se dragen de akker- en tuinbouw en de veehouderij significant bij aan het huidige mondiale gebruik: Se in de veehouderij 11% van totaal, en B in akker- en tuinbouw 12% van totaal verbruik. Prijsfluctuaties van Se en B zijn groot en wijzen op schaarste; binnen de industrie vindt recycling van deze elementen nauwelijks plaats. Binnen het voedselsysteem vindt recycling plaats van micronutriënten via hergebruik van dierlijke mest, gewasresten, compost en zuiveringsslib. Voor alle industrieel gebruikte micronutriënten zijn er alternatieven, behalve voor Co. In bodems vindt niet-duurzame ophoping plaats van Cu en Zn via mest, vooral in gebieden met een hoge veedichtheid.
Mineralen-, sporenelementen- en vitaminenbehoeften van paarden
Top, A.M. van den; Blok, M.C. ; Everts, H. - \ 2012
Lelystad : CVB, Productschap Diervoeder (CVB-documentatierapport nr. 54) - 68
paarden - diervoeding - voeding - voedering - voedingsstoffen - mineralenvoeding - sporenelementen - vitaminen - horses - animal nutrition - nutrition - feeding - nutrients - mineral nutrition - trace elements - vitamins
In deze publicatie wordt beschreven hoe de in CVB verband tot stand gekomen voedernormen voor deze voedingsstoffen tot stand zijn gekomen. De publicatie is het resultaat van een deskstudie waarbij allereerst de Duitse DLG normen en de Amerikaanse NRC normen zijn geëvalueerd. Daar waar nodig is gericht gekeken of er nieuwe studies beschikbaar zijn, of is teruggegrepen op de oorspronkelijke publicaties. Voor de macromineralen (calcium, fosfor, magnesium, natrium, kalium, chloor) zijn de voedernormen gebaseerd op de zgn. factoriële methode. Voor sporenelementen en de vitamines bleek deze benadering niet mogelijk. Het rapport bevat een groot aantal tabellen waarin de voedernormen voor de genoemde nutriënten voor alle relevante fysiologische stadia.
Trend analysis of copper and zinc in animal feed
Adamse, P. ; Egmond, H.J. van; Polanen, A. van; Bikker, P. ; Jong, J. de - \ 2011
Wageningen : Rikilt - Institute of Food Safety (Report / RIKILT 2011.012)
veevoeder - voersamenstelling - sporenelementen - koper - zink - chemische analyse - classificatie - fodder - feed formulation - trace elements - copper - zinc - chemical analysis - classification
The EC has introduced maximum inclusion levels of copper and zinc salts in animal diets from 1970 onwards and reduced these levels in recent years. In this report historical values are used to give insight into trends in levels of copper and zinc in compound feeds for animals in the Netherlands. The results of these analyses will enable the nVWA (Dutch Food and Consumer Product Safety Authority) to develop a more risk-directed sampling strategy in the National Feed Monitoring program. Over 2000 feed samples are analysed for this report. The data for this analysis are from the period between 2001 and 2009. The copper and zinc data-set contains mostly feeds for piglets, (older) pigs, sheep and to a lesser extent bovine and other species.
Zuivelproducten zijn belangrijke bronnen van micronutriënten
Groot, C.P.G.M. de - \ 2011
VoedingsMagazine 24 (2011)3. - ISSN 0922-8012 - p. 11 - 13.
melkproducten - melk - voedingsstoffen - aanbevolen dagelijkse hoeveelheden - voeding en gezondheid - voedingsstoffentekorten - voedingsstoffenbehoeften - sporenelementen - milk products - milk - nutrients - recommended dietary allowances - nutrition and health - nutrient deficiencies - nutrient requirements - trace elements
Het network of excellence EURRECA heeft tien micronutriënten geselecteerd die prioriteit verdienen bij de Europese harmonisatie van de voedingsaanbevelingen. Voor veel van de micronutrienënten zijn melk en zuivelproducten belangrijke bronnen. Zo bleek tijdens een symposium in Parijs.
Estimation of micronutrient intake distributions: development of methods to support food and nutrition policy making
Verkaik-Kloosterman, J. - \ 2011
University. Promotor(en): Pieter van 't Veer, co-promotor(en): M.C. Ocké. - [S.l.] : S.n. - ISBN 9789085859451 - 192
sporenelementen - vitaminen - voedingsstoffenopname (mens en dier) - dieet - beleid inzake voedsel - volksgezondheid - fortificatie - voedselsupplementen - trace elements - vitamins - nutrient intake - diet - food policy - public health - fortification - food supplements


Introduction
Adequate and safe micronutrient intake is important. Both insufficient and excessive intakes should be prevented as these can be associated with negative health effects. Therefore, the population intake distribution will ideally lay between insufficient and excessive intakes. For the development and evaluation of nutrition and food policy a good estimation of dietary micronutrient intake is of great importance.

Aim
Three challenges were addressed to improve the estimation of population micronutrient intake distributions: 1) how to estimate current habitual micronutrient intake when (detailed) data are lacking or data from different sources should be combined, 2) how to predict future intakes in order to support policy making, and 3) how to estimate a maximum safe fortification level per food item. The aim of this PhD-thesis is to further develop and apply statistical models which can cope with these challenges.

Methods & Results
Data from the Dutch National Food Consumption Surveys (DNFCSs) were used to develop and apply statistical models which can cope with the defined challenges. In addition, data from the Dutch food composition database (NEVO) and the Dutch dietary supplement database (NES) were used.

Three main methodological improvements have been made. First, the combination of a deterministic approach with probabilistic approaches to be able to take into account uncertainty and variability were needed. This method was applied to estimate habitual iodine and salt intake distributions. From DNFCSs no detailed information was available on the discretionary use of (iodized) salt and no up to date information was available on the use of iodized salt in industrially processed foods. Estimates of the proportion of the population discretionarily using (iodized) salt and the proportion of industrially processed foods applying iodized salt were obtained from other data sources. The model accurately estimates habitual iodine and salt intake distributions when compared with studies measuring urinary iodine and sodium excretion. Additionally a framework was developed to simulate the habitual intake distribution for potential scenarios of future fortification strategies. Within this framework, deterministic and probabilistic approaches were combined when uncertainty or variability had to be taken into account. This framework was illustrated by the estimation of habitual folate-equivalent intake for different scenarios of mandatory or voluntary fortification with folic acid. Further this framework was applied to estimate the habitual iodine intake for several potential changes in the Dutch iodine policy and also for several scenarios of salt reduction strategies.

A second methodological improvement was the development of a new statistical model to estimate habitual total micronutrient intake aggregated from food and dietary supplements. Within this 3-part model, habitual intake is estimated separately for a) intake from food for non-users of dietary supplements, b) intake from food for users of dietary supplements, and c) intake from dietary supplements for users only. Habitual total intake for the whole population was obtained by combination of the three separate habitual intake distributions (‘first shrink then add’). This 3-part model was illustrated by vitamin D intake for young children. With a more simple ‘first add then shrink’ approach the estimation of habitual total vitamin D intake distribution may give inconsistent results for the distribution of intake from foods and dietary supplements combined as compared to the intake from food only. In addition, this more simple approach may not be able to cope with multi modal distributions. With the newly developed model this inconsistency problem was solved and the multi-modal shape of the distribution as observed in the ‘raw’ data was preserved.

Third, a model calculating the maximum safe fortification level per 100 kcal of a food was developed for the Dutch situation. By considering the tolerable upper intake level and reasonable high micronutrient intakes from food and dietary supplements, the ‘free space’ for voluntary fortification was calculated. This amount was divided over the amount of energy intake that can and may be fortified. The model was applied to derive safe maximum fortification levels for vitamin A, D, and folic acid. Based on these results the risk manager decided to legally allow voluntary fortification with vitamin D and folic acid up to a maximum level of 4.5 and 100 μg/100 kcal respectively.

Conclusion
The methodological improvements have resulted in higher accuracy for estimations of habitual intake distributions, which are essential for nutritional and food policy making. Furthermore, scenario analyses provide (under specific conditions) quantitative insight into proposed changes or areas such as maximum safe fortification levels. Several results and methods described are currently being used in research to assist Dutch and European food and nutrition policy making, which shows these methodologies are of immediate value to the practice of policy development and support.

Selenium beschermt tegen vrije radicalen : uit onderzoek blijken positieve effecten op de groei
Kierkels, T. ; Lugt, G.G. van der; Heuvelink, E. - \ 2011
Onder Glas 8 (2011)1. - p. 14 - 15.
glastuinbouw - groenteteelt - sporenelementen - selenium - seleniummeststoffen - plantenontwikkeling - paprika - voeding en gezondheid - groenten - greenhouse horticulture - vegetable growing - trace elements - selenium fertilizers - plant development - sweet peppers - nutrition and health - vegetables
Selenium speelt een rol bij verschillende processen in de plant, maar het is nog onduidelijk of het ook werkelijk essentieel is. Het kan de plant in elk geval beschermen tegen vrije radicalen. Maar het internationale onderzoek concentreert zich vooral op de vraag hoe je het seleniumgehalte in planten omhoog krijgt ten bate van mens en dier.
Effect of preventive supplementation with zinc and other micronutrients on malaria and diarrhoeal morbidity in African children
Veenemans, J. - \ 2011
University. Promotor(en): Huub Savelkoul; A.M. Prentice. - s.n. - ISBN 9789085858294 - 214
zink - sporenelementen - voedselsupplementen - malaria - diarree - ziektepreventie - preventieve voeding - kinderen - tanzania - kenya - nadelige gevolgen - voedingsstoffentekorten - zinc - trace elements - food supplements - diarrhoea - disease prevention - preventive nutrition - children - adverse effects - nutrient deficiencies
Background: Zinc is important for innate and adaptive immune responses
to infection. Preventive zinc supplementation has been shown to reduce
the incidence of acute diarrhoea by 20%. Few trials have evaluated its effect
against malaria. Because trial results for both outcomes are inconsistent,
research priorities must shift from studies to measure efficacy to identifying
factors that determine the magnitude of the effect of zinc supplementation.
We hypothesized that protection by zinc supplementation depends on
concomitant supplementation with other nutrients.
Objectives: Specific objectives were: a) to assess the effect of supplementation
with zinc, alone or in combination with other nutrients, on the rates of malaria
(primary objective); b) to assess intervention effects on rates of diarrhoea and
other common diseases; c) to identify factors that determine the magnitude
of the effect of the interventions. Our studies also provided an opportunity to
assess effects of α+-thalassaemia on malaria and malaria-associated anaemia.
This haemoglobin disorder is highly prevalent in eastern Africa and that has
recently been reported to protect against severe malaria.
Methods: In a highly malaria-endemic area in rural Tanzania, we randomised
children (n=612) aged 6-60 months with height-for-age z-score ≤ –1.5 SD to
daily supplementation with: a) zinc, vitamins and other mineral elements
(‘multi-nutrients’); b) zinc; c) multi-nutrients without zinc; or d) placebo.
Those with Plasmodium infection at baseline were treated. Field staff
and participants were blinded to treatment. Sick children were detected
and evaluated in a research clinic. The primary outcome, an episode of
malaria, was pre-defined as current Plasmodium antigenaemia in children
with guardian-reported fever and any of the following: a) confirmed fever
(axillary temperature ≥ 37.5 °C), or b) unconfirmed fever with inflammation
(whole blood C-reactive protein concentrations ≥ 8 mg/L), separated by at
least 14 days from a previous malaria episode.
Results: The primary analysis included 1,572 episodes of malaria and 526
child-years of observation. The prevalence of zinc deficiency (plasma zinc
concentration < 9.9 μmol/mL) was 67% overall, and 60% in those without
inflammation (plasma C-reactive protein concentration < 8 mg/L). This
prevalence was dramatically reduced by zinc supplementation.
We found no evidence that concurrent supplementation with multi-nutrients
influenced the magnitude of the effect of zinc on rates of malaria or diarrhoea,
so that marginal effects will be presented in the remainder of this summary.
Although we found no evidence that zinc alone protected against malaria, it
reduced rates of diarrhoea by 24% (95% CI: 4%–40%) and of episodes of fever
without localising signs by 25% (4%–43%), two disorders with mutually
exclusive case definitions.
We found no effect of multi-nutrients on the overall rate of malaria episodes,
regardless the case definition used, but the effect estimate was likely
underestimated by children becoming asymptomatically infected in the
course of the intervention period. In the first 100 days of intervention, and
in the analysis of first events, supplementation with multi-nutrients, with
or without zinc, increased the hazard of malaria by one-third. In addition,
subgroup analysis indicated that this effect depended strongly on age and
iron status at baseline, with rates of episodes with parasite densities > 10,000
parasites/ μL increasing by 27 % (1%-61%) and 53% (11%–111%) in the
youngest children (6-17 months) and in children with iron deficiency, whilst
there was no evident effect in older children or those without iron deficiency
(p-values for interaction: 0.02 and 0.007).
Despite the increase in malaria rates, the children who had the lowest
haemoglobin concentrations during malaria (those aged 6-17 months)
were better able to maintain their haemoglobin concentrations when
having received multi-nutrients. Direct epidemiological evidence is
lacking, however, if and under what conditions the higher haemoglobin
concentrations during malaria (and expected reduced risk of death due to
severe malarial anemia) outweigh the possible increase in other potentially
lethal disease manifestations.
Multi-nutrient supplementation seemed to increase the rate of diarrhoea by
19% (–6% to 50%). Subgroup analysis indicated that this effect depended
on Giardia intestinalis infection at baseline (p-values for interaction: 0.03): in
those without multi-nutrients, infection was associated with a reduction in
rates of diarrhoea by 68% (34%-85%), whilst there was no evidence for such
protection in those receiving multi-nutrients. Similar effect modification was
found for fever without localizing signs.
Of 612 children in the trial, 50% had normal genotype, whilst 41% and 9%
were heterozygote and homozygous, respectively, for α+-thalassaemia. We
found no evidence of group differences in malaria rates between genotypes.
Subgroup analysis suggested, however, that the effect of α+-thalassemia
depended on age. Thus in children below 18 months, malaria rates were
increased by 30% (2%–65%) in heterozygotes, whereas they were decreased
by 20% (5%–32%) in older children (p-value for interaction: 0.001). Similar
patterns were found for homozygotes, even though estimates were less
precise due the smaller numbers of children in this age class. Based on data
from a pilot survey and a study in Kenya, we found that children with α+-
thalassaemia (particularly homozygotes) were protected against the decline in
haemoglobin concentration associated with mild to asymptomatic infections,
particularly when these infections were accompanied by inflammation.
Interpretation and conclusions for policies: We found no evidence that addition
of vitamins and other mineral elements increased the health benefits of zinc
supplements. The beneficial effects of zinc described in this thesis strengthen
the case for scaling up zinc interventions in deficient populations of African
children, without concerns that it will cause adverse effects due to malaria.
Multi-nutrient supplementation may be unsafe in malaria-endemic areas,
particularly in young children with iron deficiency. Thus the recommendation
by the World Health Organization that iron supplements should be
administered routinely to iron-deficient infants in settings with adequate
access to anti-malarial treatment is insufficiently supported by evidence and
should be reconsidered. Our results underscore that supplementation or
home fortification, even when targeting deficient subgroups in settings with
access to adequate primary care, should not be recommended in malariaendemic
areas until their safety has been demonstrated.
Honderden enzymen drijven op zink : zinkovermaat kan funest uitpakken
Kierkels, T. ; Heuvelink, E. - \ 2010
Onder Glas 7 (2010)3. - p. 18 - 19.
cultuurmethoden - plantenvoeding - sporenelementen - fotosynthese - voedingsstoffen - ph - zinkmeststoffen - mineraalovermaat - afwijkingen, planten - gewaskwaliteit - glastuinbouw - cultural methods - plant nutrition - trace elements - photosynthesis - nutrients - zinc fertilizers - mineral excess - plant disorders - crop quality - greenhouse horticulture
Zink is belangrijk voor het functioneren van honderden enzymen en andere eiwitten. Fotosynthese, vertaling van genen, aanmaak van eiwitten en hormonen drijven erop. Zinkgebrek leidt tot misvormingen en verkleuring. Een overmaat is funest voor de fotosynthese. Het element is gevoelig voor een te hoge pH
Nutritional interventions and blood pressure : role of specific micronutrients and other food components
Mierlo, L.A.J. van - \ 2010
University. Promotor(en): Frans Kok, co-promotor(en): Marianne Geleijnse; P.L. Zock. - [S.l.] : S.n. - ISBN 9789085856900 - 187
bloeddruk - dieet - ziektepreventie - maatregel op voedingsgebied - sporenelementen - hypertensie - mineralen - blood pressure - diet - disease prevention - nutritional intervention - trace elements - hypertension - minerals
Background
Elevated blood pressure is an important risk factor for cardiovascular diseases (CVD). Modest reductions in blood pressure at the population level, as can be achieved by dietary and lifestyle changes, have a large impact on the burden of CVD. Blood pressure is regulated by several physiological mechanisms, including vascular endothelial function.

This thesis
The studies described in this thesis examined the potential effects of various micronutrients and other food components on blood pressure and endothelial function. The first aim was to assess the importance of selected minerals on population blood pressure levels and the second was to investigate the vascular effects of food components other than minerals that have recently attracted attention in the field of nutrition and blood pressure.
A review of 21 national surveys showed that current dietary potassium intakes are suboptimal (1.7-3.7 gram per day). We estimated that increasing intakes to the recommended level of 4.7 gram per day can reduce population systolic blood pressure by 2-3 mmHg in Western countries, this effect being similar to that which can be achieved by reducing current sodium intakes to recommended levels. Our meta-analysis of 40 randomized controlled intervention studies showed that increasing calcium intake by ~1200 mg per day significantly lowers systolic blood pressure by 2 mmHg and diastolic blood pressure by 1 mmHg. This effect tended to be stronger in populations with lower intakes (<800 mg per day). In an 8-week placebo controlled parallel study in 124 subjects with elevated blood pressure, we found no significant blood pressure lowering effects of skimmed milk enriched in potassium (1500 or 750 mg per daily serving) combined with calcium, magnesium, selenium, vitamin C and vitamin E. However, this study was not designed to detect reductions in systolic blood pressure of 2-3 mmHg, which are still relevant at the population level.
In two 4-week placebo controlled cross-over studies, in 162 subjects with untreated elevated blood pressure, we could not demonstrate an antihypertensive effect of a yogurt drink with lactotripeptides obtained by enzymatic hydrolysis (study 1: 10.2 mg per day; study 2: 4.6 mg per day plus 350 mg added potassium). In another 2-week placebo controlled cross-over study in 35 healthy males we found no consistent effect on endothelial function and blood pressure of ~800 mg polyphenols per day from either a wine-grape mix or grape seeds. Finally, a meta-analysis of 14 randomized controlled intervention studies showed that folic acid at a high dose (≥5000 g per day), which can not be attained with a regular diet, significantly improved flow-mediated dilation by 8%.

Conclusion
Adequate potassium and calcium intakes can play an important role in the prevention of hypertension at the population level. Lactotripeptides have no relevant effect on blood pressure in Caucasian populations. The potential of grape polyphenols and folic acid to improve endothelial function is limited.
Multiple actions are needed to lower blood pressure at the population level and reduce the burden of CVD. To improve intakes of potassium and calcium, public health measures should re-emphasize the intake of fruits, vegetables, and low-fat dairy products. Further optimization of mineral intakes, in particular reduction of sodium intake, requires collaborative actions of government and food industry.

UV-C preventief en curatief te gebruiken in glastuinbouw
Arkesteijn, M. ; Hofland-Zijlstra, J.D. - \ 2010
Onder Glas 7 (2010)2. - p. 18 - 19.
botrytis - sclerotinia - meeldauw - klimaatregeling - teeltsystemen - bloementeelt - gerbera jamesonii - schimmelbestrijding - belichting - sporenelementen - glastuinbouw - snijbloemen - mildews - air conditioning - cropping systems - floriculture - fungus control - illumination - trace elements - greenhouse horticulture - cut flowers
Botrytis is een lastig probleem. Belichting met UV-C kan een oplossing bieden. Luchtbehandeling met deze methode kan als hygiënemaatregel worden toegepast om de sporendruk te verlagen. Een UV-C robot door het groentegewas en een na-oogst-behandeling met dergelijk licht zijn mogelijke alternatieven voor chemische maatregelen. Alle drie zijn ze getest en geven ze positieve resultaten. De luchtbehandeling is nog niet praktijkrijp. Inmiddels loopt er een praktijkproef met gerberabloemen
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