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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.

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    Dietary patterns for healthier cognitive ageing
    Berendsen, Agnes A.M. - \ 2017
    Wageningen University. Promotor(en): C.P.G.M. de Groot; E.J.M. Feskens, co-promotor(en): O. van de Rest. - Wageningen : Wageningen University - ISBN 9789463436014 - 190
    meal patterns - feeding habits - aging - cognition - health - food supplements - dementia - nutritional intervention - elderly - elderly nutrition - nutrition and health - maaltijdpatronen - voedingsgewoonten - verouderen - kenvermogen - gezondheid - voedselsupplementen - dementie - maatregel op voedingsgebied - ouderen - ouderenvoeding - voeding en gezondheid

    With ageing of our population and the accompanying increase in the number of people living with dementia, it is important to find modifiable risk factors to postpone the onset of cognitive decline. Diet has been proposed such a modifiable risk factor. To date, numerous studies have been conducted demonstrating a possible role of specific nutrients and foods in cognitive functioning. However, as people do not consume single nutrients, the research field has shifted towards studying dietary patterns in which synergistic effects of single nutrients and/or foods can be studied. The main aim of this thesis was to study the association of healthful dietary patterns with cognitive functioning. In addition, nutrient intake inadequacies were assessed and the potential to change dietary intake in older adults aged 65 years and older was studied.

    Chapter 2 describes nutrient intake of 245 Dutch adults aged 65-80 years. We identified the contribution of nutrient dense foods, fortified foods and dietary supplements to the total intake of micronutrients. Nutrient density of foods was evaluated using the Nutrient Rich Food score 9.3. Nutrient intake inadequacies were observed for vitamin D, vitamin B6 and selenium. Conventional foods were the main source of vitamin D, vitamin B6 and selenium intake. Foods with the highest nutrient density contributed most to total vitamin B6 intake. In order to optimize nutrient intakes of elderly, combinations of natural food sources, fortified foods and dietary supplements should be considered.

    Chapter 3 provides a systematic review of the literature on human studies up to May 2014 that examined the role of dietary patterns in relation to cognitive decline or dementia. The results demonstrate that better adherence to a Mediterranean diet was associated with less cognitive decline, dementia or Alzheimer’s Disease (AD) in four out of six cross-sectional studies, six out of 12 longitudinal studies, one trial and three meta-analyses. Other healthy dietary patterns, among which the Healthy Diet Indicator, have shown to be associated with reduced cognitive decline and/or a reduced risk of dementia in all six cross-sectional studies and six out of eight longitudinal studies. The conclusion of this literature review was that more conclusive evidence is needed to come to more targeted and detailed dietary guidelines to prevent or postpone cognitive decline.

    In chapter 4 the association between the Healthy Diet Indicator (HDI) and cognitive functioning in older adults from three different cohort studies was investigated. The cohorts included in total 21,837 subjects from Europe (SENECA and the Rotterdam Study [RS]) and the Unites States (Nurses’ Health Study [NHS]). Cognitive functioning was measured using the Mini-Mental State Examination (MMSE) in SENECA and RS, and the Telephone Interview for Cognitive Status (TICS) in NHS. In all three cohorts, the HDI was not significantly associated with cognitive decline, nor with cognitive function.

    In chapter 5 the association of long-term adherence to the Dietary Approaches to Stop Hypertension (DASH) diet with cognitive function and decline in older American women was examined. A total of 16,144 women from the Nurses’ Health Study, aged ≥70 years, who underwent cognitive testing a total of 4 times by telephone from 1995-2001 (baseline), with multiple dietary assessments between 1984 and the first cognitive exam were studied. Greater adherence to long-term DASH score was significantly associated with better average global cognition, verbal memory and TICS score at older ages, but not with cognitive decline.

    In chapter 6, the same cohort as in chapter 5 was studied to examine the association between long-term adherence to a recently developed Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet with cognitive function and decline. Higher MIND diet scores were associated with better verbal memory at older ages, but not with cognitive decline over 6 years in global cognition, verbal memory or TICS.

    Chapter 7 provides an overview of the NU-AGE (NUtrients and AGEing) dietary intervention study. The NU-AGE study is a randomized one-year intervention in 1,250 apparently healthy, independently living European subjects aged 65 to 80 years. Subjects were randomised into either the intervention group or the control group. Participants in the intervention group received dietary advice aimed at meeting the dietary recommendations of the ageing population. At the start of this thesis, the NU-AGE study was the first dietary intervention investigating the effect of a whole diet and providing targeted dietary recommendations for optimal health and quality of life in apparently healthy European elderly.

    In chapter 8, we evaluated if the NU-AGE intervention could be effective to shift the dietary intake of apparently healthy older adults aged 65-80 years living in Italy, the UK, the Netherlands, Poland, and France towards a more healthful diet. The NU-AGE index was created to assess adherence to the NU-AGE diet. At baseline and after one-year follow-up dietary intake was assessed by means of 7-day food records. In total, 1,296 participants were randomized and 1,145 participants completed the intervention (571 in intervention group, 570 in control group). After one-year follow-up, the intervention group improved mean intake of 13 out of 16 dietary recommendations of the NU-AGE diet (p<0.05) with a significant increase of the total NU-AGE index, compared to the control group (mean change in NU-AGE index 21.3±15.9, p<0.01). The NU-AGE dietary intervention, based on dietary recommendations for older adults, may be a feasible strategy to improve dietary intake in an ageing European population.

    Chapter 9 shows the results of the NU-AGE parallel randomized dietary intervention study on cognitive functioning in the Dutch NU-AGE subpopulation, including 252 older adults aged 65-80 years (123 intervention, 129 control). The primary outcome was one-year change in global cognition and in four cognitive domains as measured through a comprehensive neuropsychological test battery. Comparing the intervention with the control group, there was no effect of the intervention on cognitive functioning.

    In chapter 10 the main findings of this thesis were summarized and a reflection on methodological aspects was given. When grading the reported associations in previous studies and studies in this thesis, it was concluded that there is probable evidence for a role of the Mediterranean diet on cognitive functioning. For the DASH and MIND diet there is a possible link with cognitive functioning; for the HDI and the NU-AGE diet there is no sufficient evidence yet to conclude that there is a relation with cognitive functioning. Not only is there a need for well-designed intervention and prospective studies, we also call for communication strategies to the general public about the consumption of healthier diets to not only impact cardiovascular but also potentially impact brain health as many individuals will face progressive cognitive decline in the near future.

    Affect and cognition in attitude formation towards familiar and unfamiliar attitude objects: the case of nanotechnology
    Giesen, R.I. van - \ 2015
    Wageningen University. Promotor(en): Hans van Trijp, co-promotor(en): Arnout Fischer. - Wageningen : Wageningen University - ISBN 9789462573390 - 187
    nanotechnologie - houding van consumenten - attitudes - besluitvorming - technologie - voedseltechnologie - kennisniveau - kenvermogen - nanotechnology - consumer attitudes - attitudes - decision making - technology - food technology - knowledge level - cognition
    Together, the chapters in this thesis show that although the default is to rely on affect, in attitude formation toward unfamiliar attitude objects, people are able to draw on cognitive inferences provided that there are enough cues available (e.g. product context, high Need for Cognition, or being more often exposed). In addition, whether people rely on affect or cognition depends on which process is the easiest. The attitude component which is decisive in the attitude formation process requires the least elaborate process. This thesis contributes to a better process understanding as both affective-cognitive and deliberative-intuitive dimensions were simultaneously studied. Finally, it is concluded that attitudes toward unfamiliar attitude objects, in this case nanotechnology applications, are still subject to change. This has implications for communication about new technologies, as it is important to address both affective and cognitive aspects.
    Effect of iodine supplementation in Indian pregnant women on maternal and newborn thyroid function and cognitive development
    Jaikrishna, N. - \ 2015
    Wageningen University. Promotor(en): Michael Zimmermann, co-promotor(en): Alida Melse-Boonstra; K Srinivasan. - Wageningen : Wageningen University - ISBN 9789462573338 - 244
    jodium - maternale voeding - zwangerschap - voeding - hypothyreoïdie - schildklierziekten - schildklierwerking - jodiumhoudend zout - minerale supplementen - kenvermogen - cognitieve ontwikkeling - mineraaltekorten - voedingsstoffentekorten - iodine - maternal nutrition - pregnancy - nutrition - hypothyroidism - thyroid diseases - thyroid function - iodized salt - mineral supplements - cognition - cognitive development - mineral deficiencies - nutrient deficiencies


    Background: Iodine is a key nutrient in neurodevelopment, and the fetus is entirely dependent on the iodine intake of the mother to fulfill this important requirement for proper brain function. While this is clearly known, it is uncertain if maternal iodine nutrition should be monitored separately against what is in current practice in public health programs to control iodine deficiency. Also, it is unclear whether it is beneficial to supplement pregnant women with iodine in mild-to moderately iodine deficient and also iodine sufficient areas. Finally, the role of thyroid dysfunction in depression during pregnancy is uncertain.

    Objectives: 1) to determine whether iodine supplementation to pregnant women improves maternal and newborn thyroid function, pregnancy outcome, birth weight, infant growth and cognitive performance; 2) to assess iodine intake and potential determinants of intake, in pregnant women and their children who were sharing all meals; 3) to measure thyroid status during pregnancy and assess potential determinants of maternal thyroid function including iodine status, thyroid autoimmunity, body weight and anemia; 4) to assess the association of maternal depression, and thyroid function during pregnancy.

    Methods: 1) In a randomized placebo controlled trial (RCT), the MITCH (Maternal Iodine Supplementation and its Effects on Thyroid function and CHild Development) study, pregnant women, gestational age ≤14 weeks, in Bangalore, India, were randomized to receive either a daily supplement of 200 µg oral iodine or placebo from enrolment until delivery. Women were followed through delivery, and then with postnatal follow-up of their infants at 6 weeks, 1 and 2 year. Early neonatal development was assessed using the Neonatal Behavioral Assessment Scale (NBAS) at 6 weeks of age; neurocognitive assessment was done using the Bayley Scales of Infant Development (BSID III) at 1 and 2 years, and BRIEF-P (Behavior Rating Inventory of Executive Function) at 2 years; 2) A cross-sectional study comparing iodine status of pregnant women and their children, who were sharing all meals in Bangalore, India; 3) A cross-sectional study among 334 pregnant women ≤14 weeks of gestation, in Bangalore, India, who were screened for the RCT; 4) Secondary analysis of the longitudinal data on 318 pregnant women in the RCT.

    Results: 1) In the RCT, there were no significant differences between groups in maternal thyroid function tests or thyroid volume during gestation. The prevalence of thyroid dysfunction or anti-TPO antibodies did not differ significantly during gestation and postpartum. Postpartum, there were no significant differences between the maternal and infant groups in thyroid function, birth outcomes or UIC. Neonates whose mothers received iodine supplementation during pregnancy had better orientation scores at 6 weeks of age and lower scores of inhibition suggesting better executive function at 2 years of age although neurocognitive development on the BSID III were not significantly different between groups; 2) In the pilot study, a) median UIC in pregnant women was 172 µg/L, b) the median UIC was >150 µg/L in all trimesters and c) thyroid size was not significantly different across trimesters; the median UIC in children was 220µg/L, indicating ‘more than adequate’ iodine intake at this age. Median UIC was significantly higher in children than in their mothers (p=0.008). 3) In the cross-sectional study, 21% women were vegetarian, 19% were anemic and 23% were overweight or obese. Iodized salt was used by 98% of women and they were iodine sufficient, median UIC was 184.2 µg/L and all had normal thyroid volume. However, 18% of women had thyroid insufficiency: 3.7% had overt hypothyroidism (83% with positive TPO-Ab), 9.2% had subclinical hypothyroidism and 5.2% had hypothyroxinemia. Women consuming vegetarian diets did not have significantly lower iodine intakes or higher risk of hypothyroidism than those consuming mixed diets, but overweight/obesity and anemia predicted thyroid insufficiency; 4) In the longitudinal study, there was no significant difference in depressive symptoms between the iodine intervention and placebo groups. Women with depressive symptoms had significantly lower serum TSH compared to women without depressive symptoms in the first trimester. Pregnant women with prenatal depressive symptoms had a significantly higher number of medical symptoms.

    Conclusion: 1) Iodine supplementation in mildly iodine deficient and in iodine sufficient pregnant women was well-accepted and safe and did not increase the risk of excess iodine intake, hyper- or hypothyroidism, or thyroid autoimmunity. Though there were no significant effects of iodine supplementation on neonatal and maternal thyroid function and birth outcomes, there were modest effects on neurocognitive development of children as assessed by executive function of children at 2 years. Thus, additional follow-up of these children for neurocognitive testing at a later age when development and cognitive testing is more reliable would provide valuable add on information; 2) The iodized salt program in Bangalore, India was providing adequate iodine to women throughout pregnancy, at the expense of higher iodine intake in their children, suggesting that the current WHO/UNICEF/ICCIDD cut-off for median UIC in children indicating more-than-adequate intake may need to be reconsidered; 3) Despite iodine sufficiency, many pregnant women had thyroid insufficiency predicted by low hemoglobin and higher BMI. The prevalence of overt hypothyroidism was >5-fold higher than reported in other iodine-sufficient populations of pregnant women, thus, screening of maternal thyroid function should be considered in antenatal care at hospitals in Bangalore, India; 4) Although iodine supplementation did not affect maternal depression, we highlighted the need for systemic screening for prenatal depression during antenatal visits as it is an independent risk factor for later development of clinical depression

    Nutrition and cognition in older adults : studies on the role of glucose, sucrose, protein, vitamin B12 and folic acid
    Zwaluw, N.L. van der - \ 2014
    Wageningen University. Promotor(en): Lisette de Groot, co-promotor(en): Ondine van de Rest; Rosalie Dhonukshe-Rutten. - Wageningen : Wageningen University - ISBN 9789462571075 - 184
    ouderenvoeding - voeding - ouderen - kenvermogen - glucose - sucrose - eiwittoevoegingen - vitamine b12 - dementie - elderly nutrition - nutrition - elderly - cognition - glucose - sucrose - protein supplements - vitamin b12 - dementia

    The age-related cognitive decline and the increase in dementia patients are large problems in societies with growing ageing populations. No cure is present for dementia, while the available medication only focuses on alleviating symptoms. It is therefore of major importance to find risk factors that can modify the development of cognitive decline and dementia. Pre-clinical and observational studies suggest a role for nutrients. Evidence derived from randomized controlled trials (RCTs) is, however, limited and equivocal with most studies showing no effect and only a few studies showing a beneficial effect of a nutritional intervention. In the current thesis, we investigated the acute and longer-term effects of different nutrients, i.e. glucose and sucrose, protein, resistance-type exercise training with or without protein, and vitamin B12 and folic acid in order to optimize and preserve cognitive functions in non-demented elderly people.

    A comprehensive literature review was performed on the acute effects of glucose and sucrose on cognitive performance (Chapter 2). Glucose is the most important fuel for the brain, and as such, manipulation of the supply of glucose may affect cognitive functions. The main conclusion of our review was that a glucose load may have a short-term beneficial effect on episodic memory. Enhancing effects on other cognitive domains were less clear, partly due to the small number of studies examining these effects. Limited research was also done on the possible effects of sucrose on cognitive functions. Therefore, we investigated the acute effects of 50 g of glucose and 100 g of sucrose on a broad spectrum of cognitive functions reflecting performance on episodic memory, working memory, attention and information processing speed, and executive functions (Chapter 3). This was done by a cross-over study in 43 elderly participants who had self-reported memory complaints. In contrast to the conclusion of our review, we did not observe an effect of glucose or sucrose on episodic memory, though we showed a beneficial effect of sucrose on attention and information processing speed.

    Protein supplementation was the next nutritional intervention that was investigated. Several amino acids are precursors for neurotransmitters, and their supply may affect the synthesis and release of these neurotransmitters, and may consequently affect cognitive performance. A 24-week randomized placebo-controlled trial was carried out in 65 frail and pre-frail elderly people (Chapter 4). The protein supplementation included twice a day 15 grams of protein in the form of a drink. Reaction time improved more in the protein group compared to the placebo group, but the scores on the cognitive domains, i.e. episodic memory, attention and working memory, information processing speed, and executive functions, or the other single test scores, did not differ between treatment groups. In addition, we investigated the effects of 24 weeks resistance-type exercise training with and without protein supplementation in pre-frail and frail elderly people (Chapter 5). Exercise training without extra protein (n=62) improved performance on the domain attention and working memory. Exercise training together with protein supplementation (n=65) improved performance on information processing speed.

    Last, the role of vitamin B12 and folate on cognitive health was investigated. Low levels of these nutrients can increase homocysteine levels, which is a suggested risk factor for cognitive decline. The effect of daily supplementation with 500 µg vitamin B12 and 400 µg folic acid was investigated in 2,919 participants for two years (Chapter 6). Global cognitive function and episodic memory were assessed in the total study population, whereas extensive neuropsychological testing was done in a subpopulation (n=856). B-vitamin supplementation did not improve cognitive domain scores. Only a small, though significant, effect was observed on global cognitive performance, measured by the Mini-Mental State Examination, but this was suggested to be due to chance. Brain MRI scans were made in a subgroup (n=218) after two years of intervention to obtain volumetric measures of grey and white matter, and total brain volume (Chapter 7). We investigated the cross-sectional associations between follow-up levels of folate, homocysteine and three vitamin B12 status biomarkers, e.g. methylmalonic acid, holotranscobalamin and serum vitamin B12, and brain volumes. Fully adjusted regression models showed a borderline significant association between plasma homocysteine and total brain volume, with a stronger association in the group that received B-vitamin supplementation. Serum B12 and holotranscobalamin were not associated with brain volumes, whereas high methylmalonic acid levels were associated with lower brain volumes in the group that received B-vitamins. In contrast, higher folate levels were associated with lower total brain volumes. In addition, when comparing the group that received two years of B-vitamin supplementation and those who did not, we observed lower brain volumes in the B-vitamin group, which might be a result of a difference in age between the two groups.

    To conclude, the nutritional intervention studies showed little evidence for a beneficial effect on cognitive performance in relatively healthy older adults. Given the large problem of dementia, research on modifiable risk factors, including nutrition, should continue, with well thought out research methods, including large and long-term observational and intervention studies with high-sensitive study populations and early biomarkers (e.g. imaging techniques) for cognitive decline in combination with neuropsychological tests. In this way, nutrition can be added to the list of lifestyle factors that can fight dementia.

    Voeding en beweging ter preventie van cognitieve achteruitgang
    Severs, A. ; Rest, O. van de; Groot, C.P.G.M. de; Loon, L.J.C. van - \ 2014
    VoedingsMagazine 27 (2014)1. - ISSN 0922-8012 - p. 18 - 20.
    ouderen - ouderenvoeding - eiwittoevoegingen - dementie - kenvermogen - lichaamsbeweging - voeding en gezondheid - voedingsstoffen - elderly - elderly nutrition - protein supplements - dementia - cognition - exercise - nutrition and health - nutrients
    Dementie wordt een steeds groter en kostbaarder probleem door de vergrijzing. Wetenschappers zijn naarstig op zoek naar mogelijkheden om het tij te keren. Zo ook Ondine van de Rest, onderzoeker aan Wageningen University. Haar onderzoek is gericht op de rol van voeding bij leeftijdsgerelateerde cognitieve achteruitgang. Samen met prof. dr.Lisette de Groot, hoogleraar voeding voor de oudere mens aan Wageningen Universiteit, en Prof. Dr. Luc van Loon, hoogleraar fysiologie van inspanning aan Maastricht Universiteit, voerde ze binnen het Top Instituut Food and Nutrition (TIFN) een interventiestudie uit bij ouderen naar het effect van eiwitsuppletie en beweging op de cognitie.
    Bones, brains and B-vitamins : the impact of vitamin B12, folate and homocysteine on bone health and cognitive function in elderly
    Wijngaarden, J.P. van - \ 2013
    Wageningen University. Promotor(en): Lisette de Groot, co-promotor(en): Rosalie Dhonukshe-Rutten. - Wageningen : Wageningen UR - ISBN 9789461737151 - 192
    botontkalking - kenvermogen - ouderen - beenderen - vitamine b12 - foliumzuur - homocysteïne - vitaminetoevoegingen - botbreuken - voedingstoestand - osteoporosis - cognition - elderly - bones - vitamin b12 - folic acid - homocysteine - vitamin supplements - bone fractures - nutritional state


    An elevated homocysteine level has been indicated as a risk factor for cardiovascular disease, cognitive decline, and fractures. Supplementation of vitamin B12 and folic acid in order to normalize homocysteine levels might be of substantial public health importance as this might reduce the risk for several age-related conditions. This thesis focuses on two health outcomes frequently associated with elevated homocysteine levels and low levels of vitamin B12 and folate: osteoporosis and cognitive decline later in life.


    Findings are presented in the context of a model which links dietary intake to biomarkers of nutritional status and subsequently to health outcomes. Two systematic reviews with meta-analyses investigated the current status of knowledge about the association of vitamin B12 intake and status with cognitive function, and the association of homocysteine, vitamin B12 and folate status with bone health. Baseline data of the B-PROOF study were used to assess 1) the association of vitamin B12 intake with status according to four biomarkers (vitamin B12, holotranscobalamin (holoTC), methylmalonic acid (MMA) and homocysteine), 2) the mutual association among these four vitamin B12 biomarkers and 3) the association between homocysteine, vitamin B12 biomarkers, folate and cognitive function. The effect of 2-year daily vitamin B12 (500 μg) and folic acid (400 μg) supplementation on fracture risk was assessed in the B-PROOF study, a large (N=2919) randomized controlled trial in elderly people (aged ≥65 years) with an elevated homocysteine level (≥12.0 µmol/L).


    The systematic review of the literature showed no or inconsistent associations of vitamin B12 intake with cognitive function. Furthermore, serum vitamin B12 was not associated with risk of dementia, global cognition or memory. Studies on MMA and holoTC reported significant associations with risk of dementia, Alzheimer’s disease and global cognition. A meta-analysis showed that serum/plasma vitamin B12 per 50 pmol/L was borderline significantly associated with a lower fracture risk (RR=0.96, 95% CI = 0.92-1.00) and that homocysteine was significantly associated with a higher fracture risk (RR=1.04, 95% CI = 1.02-1.07). Meta-analyses regarding vitamin B12, folate and homocysteine levels and BMD did not show significant associations.

    In the B-PROOF study a doubling of vitamin B12 intake was associated with 9% higher levels of vitamin B12, 15% higher holoTC, 9% lower MMA and 2% lower homocysteine, saturation of biomarkers occurs with dietary intakes of >5 μg B12. Levels of MMA and homocysteine were higher when vitamin B12 levels were below 330 pmol/L and when holoTC levels were below 100 pmol/L, with a steep elevation when levels of vitamin B12 and HoloTC were below 220 and 50 pmol/L respectively. At baseline, levels of vitamin B12 and holoTC were not associated with cognitive function in any cognitive domain. Levels of homocysteine (β= -0.009), folate (β= 0.002), MMA (β= -0.163) and the wellness score – a vitamin B12 biomarker combination score - (β= 0.048) were significantly associated with the domain of episodic memory. Additionally, homocysteine (β= -0.015) and the wellness score (β= 0.103) were significantly associated with the domain information processing speed.

    The B-PROOF intervention did not lower the risk of fracture in the total population (HR=0.84, 95% CI = 0.58-1.22). Per protocol subgroup analysis of elderly aged >80 years, showed a lower risk of fracture in the intervention group (HR=0.28, 95% CI 0.10-0.74). We observed more cancer cases in the intervention group (HR=1.55, 95% CI = 1.04-2.30) compared to the placebo group. We cannot rule out the possibility of accelerated cancer progression as a possible negative side effect.


    Our literature reviews and observational data confirm an association of levels of homocysteine, vitamin B12 and folate with cognitive function and fracture risk in elderly. Supplementation with vitamin B12 and folic acid did not lower the risk of fracture in the total study population. Though positive effects on fracture incidence emerged in elderly aged >80 years, these benefits should be weighed against potential risks.

    Cortical mechanisms underlying low-level motion processing in the visual system of human and non-human primates
    Bours, R.J.E. - \ 2010
    Wageningen University. Promotor(en): Johan van Leeuwen; R.J.A. Wezel, co-promotor(en): Martin Lankheet. - [S.l.] : S.n. - ISBN 9789085857945 - 158
    ogen - beweging - mens - primaten - hersenen - neurobiologie - neurowetenschap - geest - kenvermogen - eyes - movement - man - primates - mind - neurobiology - neuroscience - cognition
    Micronutrients, omega-3 fatty acids and cognitive performance in Indian schoolchildren
    Eilander, J.H.C. - \ 2009
    Wageningen University. Promotor(en): Frans Kok, co-promotor(en): S.J.M. Osendarp; S. Muthayya. - [S.l. : S.n. - ISBN 9789085854708 - 175
    sporenelementen - meervoudig onverzadigde vetzuren - cognitieve ontwikkeling - mentale vaardigheid - minerale supplementen - fortificatie - ondervoeding - schoolkinderen - india - omega-3 vetzuren - kenvermogen - trace elements - polyenoic fatty acids - cognitive development - mental ability - mineral supplements - fortification - undernutrition - school children - india - omega-3 fatty acids - cognition

    In developing countries, approximately 30-40% of school-age children suffer from iodine and iron deficiencies. Poverty and consumption of monotonous diets are underlying causes of inadequate intakes of micronutrients and omega-3 fatty acids and may have severe consequences for children’s cognitive development. Multiple micronutrient interventions have shown to benefit mental performance of children, but a systematic evaluation of the evidence is currently lacking. The omega-3 fatty acid, -linolenic acid (ALA) is converted into docosahexaenoic acid (DHA), a major structural component of the brain, which is important for normal development and maintenance of brain function. At present, it is unclear whether additional intake of omega-3 fatty acids improves cognitive performance in children.
    The aim of this thesis was to investigate the role of multiple micronutrients and omega-3 fatty acids on cognitive performance in school-age children living in deprived environments, thereby addressing three main research questions.
    The first query concerned the investigation of the size of effects of multiple micronutrient interventions on different cognitive domains. Findings of our meta-analysis comprising 17 studies in children 5-16 years of age, suggested that multiple micronutrients were beneficial for fluid intelligence (i.e. reasoning abilities) (0.14 SD; 95% CI: -0.02, 0.29) and academic performance (0.30 SD; 95% CI: 0.01, 0.58). Crystallized intelligence (i.e. acquired knowledge) seemed not affected (-0.03 SD; 95% CI: -0.21, 0.15) and for the other cognitive domains data were too limited to draw firm conclusions.
    Secondly, we examined the role of omega-3 fatty acids on children’s cognitive development, for which a literature review was conducted. Associations between omega-3 fatty acid status or dietary intake and cognitive performance were investigated by cross-sectional analysis using baseline data of a randomized controlled trial in 598 Indian schoolchildren (see below for details). We found no evidence for a beneficial effect of additional intake of omega-3 fatty acids, and of DHA in particular, on cognitive development in school-age children. Neither there was a significant relationship between omega-3 fatty acid status and cognitive performance.
    Lastly, we studied the effect of different doses of micronutrients and omega-3 fatty acids, and their interaction, on cognitive performance. For that purpose, a randomized controlled trial in 598 Indian schoolchildren aged 6-10 years was conducted from November 2005 until March 2007. Children received either 15% or 100% of the Recommended Dietary Allowance of micronutrients in combination with either a low (140 mg ALA) or high dose (900 mg ALA plus 100 mg DHA) of omega-3 fatty acids for 12 months. Cognitive function was measured at baseline, 6 and 12 months. Our results showed that with some small differential effects on short term memory at 6 months (0.11 SD; 95% CI: 0.01-0.20) and fluid intelligence at 6 months (-0.10 SD; 95% CI: -0.17, -0.03) and 12 months (-0.12 SD; 95% CI: -0.20, -0.04), the high and low dose of micronutrients were as effective for improving retrieval ability, cognitive speediness and overall cognitive performance. Neither there were differences between the omega-3 fatty acid treatments, nor an interaction between micronutrients and omega-3 fatty acids on cognitive outcomes.
    In conclusion, although multiple micronutrients may benefit intellectual performance of schoolchildren, development of public health guidelines is currently premature. Further investigation on doses and composition of micronutrients would be needed to identify a cost-effective micronutrient supplement to optimize cognitive performance in children. Presently, no evidence exists for a positive effect of omega-3 fatty acids on cognitive performance in healthy children. A final trial using a higher dose and sufficiently long duration would be needed to conclude whether omega-3 fatty acid supplementation improves mental development at school age.
    Very long-chain n-3 polyunsaturated fatty acids: a head start to win some years between the ears?
    Dullemeijer, C. - \ 2009
    Wageningen University. Promotor(en): Frans Kok; R.J. Brummer, co-promotor(en): I.A. Brouwer. - [S.l.] : S.n. - ISBN 9789085853770 - 136
    vetzuren met een lange keten - hersenen - cognitieve ontwikkeling - mentale vaardigheid - visoliën - ouderen - vaatziekten - omega-3 vetzuren - kenvermogen - long chain fatty acids - brain - cognitive development - mental ability - fish oils - elderly - vascular diseases - omega-3 fatty acids - cognition
    Very long-chain n-3 (or omega-3) polyunsaturated fatty acids have attracted considerable public interest during the past few years for their potential beneficial role in cognitive performance. The proposed benefits stretch from advantages in developing brains of infants and children to preventing cognitive decline at old age.
    In this thesis, we first examined the role of very long-chain n-3 PUFA at the beginning of the lifespan. We investigated the effects of dietary very long-chain n-3 PUFA on the fatty acid composition of the several brain lobes in juvenile pigs, and showed that a diet enriched with fish oil resulted in higher proportions of DHA in the frontal, parietal and occipital brain lobes compared with the temporal brain lobe. These findings suggest a region-specific incorporation of DHA in the developing brain, which may guide future research into the mechanism by which very long-chain n-3 PUFA may in involved in brain development and function.
    Subsequently, we investigated the role of very long-chain n-3 PUFA near the end of the lifespan. In a population of older adults, we investigated the association between very long-chain n-3 PUFA and cognitive decline over three years in multiple cognitive domains. We demonstrated that higher plasma proportions of very long-chain n-3 PUFA were associated with less decline in the cognitive domains sensorimotor speed and complex speed, but not in memory, information-processing speed and word fluency, compared with lower plasma proportions of very long-chain n-3 PUFA. These results suggest a beneficial role of very long-chain n-3 PUFA in the speed-related cognitive domains, which justifies future research in this area with sensitive cognitive outcome measurements that provide domain-specific information.
    Finally, we touched upon the role of very long-chain n-3 PUFA in the macrovascular and the microvascular blood supply in the head region. We showed that plasma very long-chain n-3 PUFA were not associated with changes in carotid intima-media thickness and common carotid distension in a healthy older adult population. This may suggest that the role of very long-chain n-3 PUFA in a healthy population extends in particular to the smaller blood vessels. The role of very long-chain n-3 PUFA in the microcirculation of the brain could therefore be an interesting future direction of research. Although we did not directly investigate the role of very long-chain n-3 PUFA in the brain microcirculation, we did investigate whether plasma very long-chain n-3 PUFA were associated with age-related hearing loss over a period of three years in older adults. Since microvascular disease may decrease the blood supply to the highly vascularised cochlea, this may result in age-related hearing loss. We showed that higher plasma proportions of very long-chain n-3 PUFA were indeed associated with less age-related hearing loss compared with lower plasma proportions of very long-chain n-3 PUFA which implies that the hypothesis of improved microcirculation, if proven correct, may have far-reaching consequences.
    In summary, this thesis showed that very long-chain n-3 PUFA have region-specific effects on the developing brain and that higher plasma proportions of very long-chain n-3 PUFA were associated with less decline in the speed-related cognitive domains and less age-related hearing loss. Further research is required to establish the role of very long-chain n-3 PUFA in the developing as well as the aging brain and to investigate the underlying mechanisms.

    “Very long-chain n-3 polyunsaturated fatty acids: a head start to win some years between the ears?” PhD-thesis by Carla Dullemeijer, Top Institute Food and Nutrition and Division of Human Nutrition, Wageningen University, Wageningen, the Netherlands, May 15, 2009
    Determinants of cognitive decline in older European men
    Gelder, B.M. van - \ 2007
    Wageningen University. Promotor(en): Daan Kromhout, co-promotor(en): M.A.R. Tijhuis; S. Kalmijn. - [S.l.] : S.n. - ISBN 9789085046493 - 157
    cognitieve ontwikkeling - mentale vaardigheid - dieet - ouderen - ouderdom - mannen - europa - kenvermogen - sociale factoren - cognitive development - mental ability - diet - elderly - old age - men - europe - cognition - social factors
    In our ageing population, the number of persons with cognitive impairment, dementia and Alzheimer's disease still increase and cause many problems for the elderly themselves, their relatives and caregivers and for health care. Therefore, the need for preventive action is high. In this thesis we identified social, lifestyle and dietary risk factors for the postponement of cognitive impairment and decline in elderly European men.

    For the results presented in this thesis, data from theFinland,Italyand the Netherlands Elderly (FINE) Study were used. This prospective population-based cohort study was carried out between 1985 and 2000 among 2,285 Finnish, Italian and Dutch men bornbetween 1900 - 1920. Cognitive functioning was measured with the Mini-Mental State Examination (MMSE).

    In the FINE Study, cognitive functioning decreased on average with 1.5 points during the 10-year follow-up period. This decline was due to an age effect, but also to a period and birth cohort effect.

    Men who were married or who lived with others during five years had at least a two times smaller subsequent 10-year cognitive decline compared with men who lost a partner, who were unmarried, who started to live alone and who lived alone during these five years.

    Cognitive decline did not differ among men with a high or low duration of physical activity at baseline. However, men who participated in activities with at leasta medium-low intensity had a 1.8 to 3.5 times smaller cognitive decline compared with men who participated in activities with lowest intensity. Moreover, a decrease in duration or intensity of physical activity resulted respectively in a 2.6 or 3.6 times stronger cognitive decline than maintaining duration or intensity.

    Men who consumed coffee had a two times smaller 10-year cognitive decline than non-consumers. In addition, an inverse and J-shaped association between the number of cups of coffee per day consumed and 10-year cognitive decline was present, with the least decline for men consuming three cups of coffee per day.

    Fish consumers had significantly less 5-year subsequent cognitive decline than non-consumers. A linear trend was observed for the relation between the intake of the n-3 fatty acids EPA + DHA and cognitive decline. An average difference of about 380 mg/day in EPA + DHA intake was associated with a 1.1 points difference in cognitive decline.

    Men whose cognition decreased between 1990 and 1995 had a twofold higher risk of dying in the following five years compared with men whose cognition was stable. Mortality risk of men whose cognition improved between 1995 and 2000 was not different from men with a stable cognition.

    The associations between marital status, living situation and physical activity are strong and provide in combination with the existing literature enough evidence for justifying public health recommendations for postponing cognitive decline. However, our findings on coffee and fish consumption and on the intake of the fatty acids EPA + DHA in relation with cognitive functioning need confirmation in other studies.
    Milde vitamine B12 deficiëntie en het cognitief functioneren van ouderen : de effectiviteit van orale supplementen
    Eussen, S.J.P.M. - \ 2006
    Wageningen University. Promotor(en): Wija van Staveren; W.H.L. Hoefnagels, co-promotor(en): Lisette de Groot. - [S.l.] : S.n. - ISBN 9789085044314 - 142
    vitamine b12 - vitaminetekorten - mentale vaardigheid - verstandelijk gehandicapt - vitaminetoevoegingen - bijvoeding - ouderen - ouderdom - kenvermogen - vitamin b12 - vitamin deficiencies - mental ability - mental retardation - vitamin supplements - supplementary feeding - elderly - old age - cognition
    Cobalamin deficiency is common in older people and has been recognised as a possible cause for several clinical manifestations such as anaemia and cognitive impairment. Markers for cobalamin deficiency include increased concentrations of plasma total homocysteine (tHcy) and methylmalonic acid (MMA), and decreased concentrations of holotranscobalamin (holoTC). Cross sectional analysis in this thesis confirmed that impaired cognitive performance was associated with relatively unfavourable concentrations of markers for cobalamin status. These results are in line with findings from previous cross-sectional and prospective studies and suggest a role for cobalamin status in cognitive function, in particular because cobalamin deficiency is highly prevalent in old age. According to our recruitment activities it appeared that 26.6% of the older people had mild cobalamin deficiency, which we defined as low to low-normal cobalamin concentrations in combination with increased MMA concentrations. Normalizing mild cobalamin deficiency, defined as a decrease of respectively 80% to 90% of the estimated maximum reduction in plasma MMA concentrations, could be achieved by supplementing daily oral doses of 647 mg to 1032 mg crystalline cobalamin. The main purpose of our research was to investigate whether daily supplementation with such a high dose of oral cobalamin alone or in combination with folic acid has beneficial effects on cognitive function in people aged 70 years or older with mild cobalamin deficiency. We did this in a double-blind, placebo-controlled trial with a relatively large number of carefully selected participants, and an extensive assessment of cognitive function. In total, 195 individuals were randomized to receive either 1,000 μg cobalamin, or 1,000 μg cobalamin + 400 μg folic acid, or placebo for 24 weeks. Markers for cobalamin status and cognitive function were assessed before and after 24 weeks of treatment. Assessment of cognitive function included the domains of attention, construction, sensomotor speed, memory and executive function. Cobalamin status did not change in the placebo group, whereas oral cobalamin supplementation corrected mild cobalamin deficiency. Improvement in one domain (memory function) was observed in all treatment groups, and was greater in the placebo group than in the group who received cobalamin alone ( P = 0.0036). Oral supplementation with cobalamin alone or in combination with folic acid for 24 weeks was not associated with improvements in other cognitive functions. Blood collection after cessation of oral cobalamin supplementation showed that adequate cobalamin status may maintain for a period of up to 5 months after cessation. Despite the null finding of this trial, recent studies provide clues for future research in improving cognitive function.
    Conversation and cognition
    Molder, H.F.M. te; Potter, Jonathan - \ 2005
    Cambridge : Cambridge University Press - ISBN 9780521790208 - 284
    communicatie - informatie - verbale communicatie - psychologie - kenvermogen - cognitieve psychologie - sociale kennis - communication - information - verbal communication - psychology - cognition - cognitive psychology - social cognition
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