Rosalie A. M. Dhonukshe-Rutten

Homocysteine and Vitamin B12 Status Relate to Bone Turnover Markers, Broadband Ultrasound Attenuation, and Fractures in Healthy Elderly People

Hyperhomocysteinemia may contribute to the development of osteoporosis. The relationship of Hcy and vitamin B12 with bone turnover markers, BUA, and fracture incidence was studied in 1267 subjects of the Longitudinal Aging Study Amsterdam. High Hcy and low vitamin B12 concentrations were significantly associated with low BUA, high markers of bone turnover, and increased fracture risk.

Current micronutrient recommendations in Europe: towards understanding their differences and similarities

BackgroundNowadays most countries in Europe have established their own nutrient recommendations to assess the adequacy of dietary intakes and to plan desirable dietary intakes. As yet there is no standard approach for deriving nutrient recommendations, they may vary from country to country. This results in different national recommendations causing confusion for policy-makers, health professionals, industry, and consumers within Europe. EURRECA (EURopean micronutrient RECommendations Aligned) is a network of excellence funded by the European Commission (EC), and established to identify and address the problem of differences between countries in micronutrient recommendations. The objective of this paper is to give an overview of the available micronutrient recommendations in Europe, and to provide information on their origin, concepts and definitions. Furthermore this paper aims to illustrate the diversity in European recommendations on vitamin A and vitamin D, and to explore differences and commonalities in approaches that could possibly explain variations observed.MethodsA questionnaire was developed to get information on the process of establishing micronutrient recommendations. These questionnaires were sent to key informants in the field of micronutrient recommendations to cover all European countries/regions. Also the latest reports on nutrient recommendations in Europe were collected. Standardisation procedures were defined to enable comparison of the recommendations. Recommendations for vitamin A and vitamin D were compared per sex at the ages 3, 9 months and 5, 10, 15, 25, 50 and 70 years. Information extracted from the questionnaires and reports was compared focusing on: (1) The concept of recommendation (recommended daily allowance (RDA), adequate intake (AI) or acceptable range), (2) The year of publication of the report (proxy for available evidence), (3) Population groups defined, (4) Other methodological issues such as selected criteria of adequacy, the type of evidence used, and assumptions made.ResultsTwenty-two countries, the World Health Organization (WHO)/the Food and Agriculture Organization of the United Nations (FAO) and the EC have their own reports on nutrient recommendations. Thirteen countries based their micronutrient recommendations on those from other countries or organisations. Five countries, WHO/FAO and the EC defined their own recommendations. The DACH-countries (Germany, Austria and Switzerland) as well as the Nordic countries (Norway, Sweden, Finland, Denmark and Iceland) cooperated in setting recommendations. Greece and Portugal use the EC and the WHO/FAO recommendations, respectively and Slovenia adopted the recommendations from the DACH-countries. Rather than by concepts, definitions, and defined population groups, variability appears to emerge from differences in criteria for adequacy, assumptions made and type of evidence used to establish micronutrient recommendations.DiscussionThe large variation in current micronutrient recommendations for population groups as illustrated for vitamin A and vitamin D strengthens the need for guidance on setting evidence based, up-to-date European recommendations. Differences in endpoints, type of evidence used to set recommendations, experts’ opinions and assumptions are all likely to contribute to the identified variation. So far, background information was not sufficient transparent to disentangle the relative contribution of these different aspects.ConclusionEURRECA has an excellent opportunity to develop tools to improve transparency on the approaches used in setting micronutrient recommendations, including the selection of criteria for adequacy, weighing of evidence, and interpretation of data.

Dietary intake and status of folate and vitamin B12 and their association with homocysteine and cardiovascular disease in European populations

Background/Objectives:Folate and vitamin B12 have been suggested to play a role in chronic diseases like cardiovascular diseases. The objectives are to give an overview of the actual intake and status of folate and vitamin B12 in general populations in Europe, and to evaluate these in view of the current vitamin recommendations and the homocysteine concentration.Methods:Searches in Medline with ‘folic acid’, ‘folate’ and ‘vitamin B12’, ‘B12’ or ‘cobalamin’ as key words were combined with the names of the European countries. Populations between 18 and 65 years were included.Results:Sixty-three articles reporting on studies from 15 European countries were selected. Low folate intakes were observed in Norway, Sweden, Denmark and the Netherlands. Low intakes of vitamin B12 were not common and only seen in one small Greek study. In the countries with a low intake of folate, the recommended levels were generally not achieved, which was also reflected in the folate status. Vitamin B12 intake was not strongly associated with the vitamin B12 status, which can explain why in the Netherlands and Germany the vitamin B12 status was inadequate, despite sufficient intake levels. In countries with a low folate intake in particular, the Hcy concentration was higher than ideal.Conclusions:Populations from the Nordic countries, the Netherlands, Germany and Greece may need to improve their intakes of folic acid, B12 or both to either meet the recommendations or to optimize their statuses. This could be achieved via a food-based approach, food fortification or supplements.

Rationale and design of the B-PROOF study, a randomized controlled trial on the effect of supplemental intake of vitamin B12 and folic acid on fracture incidence

BackgroundOsteoporosis is a major health problem, and the economic burden is expected to rise due to an increase in life expectancy throughout the world. Current observational evidence suggests that an elevated homocysteine concentration and poor vitamin B12 and folate status are associated with an increased fracture risk. As vitamin B12 and folate intake and status play a large role in homocysteine metabolism, it is hypothesized that supplementation with these B-vitamins will reduce fracture incidence in elderly people with an elevated homocysteine concentration.Methods/DesignThe B-PROOF (B-Vitamins for the PRevention Of Osteoporotic Fractures) study is a randomized double-blind placebo-controlled trial. The intervention comprises a period of two years, and includes 2919 subjects, aged 65 years and older, independently living or institutionalized, with an elevated homocysteine concentration (≥ 12 μmol/L). One group receives daily a tablet with 500 μg vitamin B12 and 400 μg folic acid and the other group receives a placebo tablet. In both tablets 15 μg (600 IU) vitamin D is included. The primary outcome of the study is osteoporotic fractures. Measurements are performed at baseline and after two years and cover bone health i.e. bone mineral density and bone turnover markers, physical performance and physical activity including falls, nutritional intake and status, cognitive function, depression, genetics and quality of life. This large multi-center project is carried out by a consortium from the Erasmus MC (Rotterdam, the Netherlands), VUmc (Amsterdam, the Netherlands) and Wageningen University, (Wageningen, the Netherlands), the latter acting as coordinator.DiscussionTo our best knowledge, the B-PROOF study is the first intervention study in which the effect of vitamin B12 and folic acid supplementation on osteoporotic fractures is studied in a general elderly population. We expect the first longitudinal results of the B-PROOF intervention in the second semester of 2013. The results of this intervention will provide evidence on the efficacy of vitamin B12 and folate supplementation in the prevention of osteoporotic fractures.Trial RegistrationThe B-PROOF study is registered with the Netherlands Trial (NTR NTR1333) and with ClinicalTrials.gov (NCT00696514).

How we will produce the evidence-based EURRECA toolkit to support nutrition and food policy

BackgroundThere is considerable variation in the recommended micronutrient intakes used by countries within Europe, partly due to different methodologies and concepts used to determine requirements and different approaches used to express the recommendations. As populations become more mobile and multi-national, and more traditional foods become available internationally, harmonised recommendations based on up to date science are needed. This was recognised by the European Commission’s (EC) Directorate-General (DG) Research in their 2005 call for proposals for a Network of Excellence (NoE) on ’nutrient status and requirements of specific vulnerable population groups’. EURopean micronutrient RECommendations Aligned (EURRECA), which has 34 partners representing 17 European countries, started on its 5-year EC-funded programme in January 2007. The programme of work was developed over 2 years prior to submitting an application to the EC. The Network’s first Integrating Meeting (IM) held in Lisbon in April 2007, and subsequent consultations, has allowed further refinement of the programme.AimThis paper presents the rationale for the EURRECA Network’s roadmap, which starts by establishing the status quo for devising micronutrient recommendations. The Network has the opportunity to identify previous barriers and then explore ’evidence-based’ solutions that have not been available before to the traditional panels of experts. The network aims to produce the EURRECA ’toolkit’ to help address and, in some cases, overcome these barriers so that it can be used by those developing recommendations.ResultsThe status quo has been largely determined by two recent initiatives; the Dietary Reference Intake (DRI) reports from the USA and Canada and suggestions for approaches to international harmonisation of nutrient-based dietary standards from the United Nations University (UNU). In Europe, the European Food Safety Authority (EFSA) has been asked by the EC’s Directorate-General for Health and Consumer Protection to produce values for micronutrient recommendations. Therefore, EURRECA will draw on the uniqueness of its consortium to produce the sustainable EURRECA toolkit, which will help make such a task more effective and efficient. Part of this uniqueness is the involvement in EURRECA of small and medium-sized enterprises (SMEs), consumer organisations, nutrition societies and other stakeholders as well as many scientific experts. The EURRECA toolkit will contain harmonised best practice guidance for a more robust science base for setting micronutrient recommendations. Hence, in the future, the evidence base for deriving nutrient recommendations will have greater breadth and depth and will be more transparent.ConclusionsThe EURRECA Network will contribute to the broader field of food and nutrition policy by encouraging and enabling the alignment of nutrient recommendations. It will do this through the development of a scientific toolkit by its partners and other stakeholders across Europe. This will facilitate and improve the formulation of micronutrient recommendations, based on transparently evaluated and quantified scientific evidence. The Network aims to be sustainable beyond its EC funding period.

Effect of daily vitamin B-12 and folic acid supplementation on fracture incidence in elderly individuals with an elevated plasma homocysteine concentration: B-PROOF, a randomized controlled trial

BACKGROUND Elevated plasma homocysteine concentrations are a risk factor for osteoporotic fractures. Lowering homocysteine with combined vitamin B-12 and folic acid supplementation may reduce fracture risk. OBJECTIVE This study [B-vitamins for the PRevention Of Osteoporotic Fractures (B-PROOF)] aimed to determine whether vitamin B-12 and folic acid supplementation reduces osteoporotic fracture incidence in hyperhomocysteinemic elderly individuals. DESIGN This was a double-blind, randomized, placebo-controlled trial in 2919 participants aged ≥65 y with elevated homocysteine concentrations (12-50 μmol/L). Participants were assigned to receive daily 500 μg vitamin B-12 plus 400 μg folic acid or placebo supplementation for 2 y. Both intervention and placebo tablets also contained 600 IU vitamin D3. The primary endpoint was time to first osteoporotic fracture. Exploratory prespecified subgroup analyses were performed in men and women and in individuals younger than and older than age 80 y. Data were analyzed according to intention-to-treat and per-protocol principles. RESULTS Osteoporotic fractures occurred in 61 persons (4.2%) in the intervention group and 75 persons (5.1%) in the placebo group. Osteoporotic fracture risk was not significantly different between groups in the intention-to-treat analyses (HR: 0.84; 95% CI: 0.58, 1.21) or per-protocol analyses (HR: 0.81; 95% CI: 0.54, 1.21). For persons aged >80 y, in per-protocol analyses, osteoporotic fracture risk was lower in the intervention group than in the placebo group (HR: 0.27; 95% CI: 0.10, 0.74). The total number of adverse events (including mortality) did not differ between groups. However, 63 and 42 participants in the intervention and placebo groups, respectively, reported incident cancer (HR: 1.56; 95% CI: 1.04, 2.31). CONCLUSIONS These data show that combined vitamin B-12 and folic acid supplementation had no effect on osteoporotic fracture incidence in this elderly population. Exploratory subgroup analyses suggest a beneficial effect on osteoporotic fracture prevention in compliant persons aged >80 y. However, treatment was also associated with increased incidence of cancer, although the study was not designed for assessing cancer outcomes. Therefore, vitamin B-12 plus folic acid supplementation cannot be recommended at present for fracture prevention in elderly people. The B-PROOF study was registered with the Netherlands Trial Register (trialregister.nl) as NTR1333 and at clinicaltrials.gov as NCT00696414.

Vitamin B-12 deficiency stimulates osteoclastogenesis via increased homocysteine and methylmalonic acid

The risk of nutrient deficiencies increases with age in our modern Western society, and vitamin B12 deficiency is especially prevalent in the elderly and causes increased homocysteine (Hcy) and methylmalonic acid (MMA) levels. These three factors have been recognized as risk factors for reduced bone mineral density and increased fracture risk, though mechanistic evidence is still lacking. In the present study, we investigated the influence of B12, Hcy, and MMA on differentiation and activity of bone cells. B12 deficiency did not affect the onset of osteoblast differentiation, maturation, matrix mineralization, or adipocyte differentiation from human mesenchymal stem cells (hMSCs). B12 deficiency caused an increase in the secretion of Hcy and MMA into the culture medium by osteoblasts, but Hcy and MMA appeared to have no effect on hMSC osteoblast differentiation. We further studied the effect of B12, Hcy, and MMA on the formation of multinucleated tartrate-resistant acid phosphatase–positive osteoclasts from mouse bone marrow. We observed that B12 did not show an effect on osteoclastogenesis. However, Hcy as well as MMA were found to induce osteoclastogenesis in a dose-dependent manner. On the basis of these results, we conclude that B12 deficiency may lead to decreased bone mass by increased osteoclast formation due to increased MMA and Hcy levels.

EURRECA's Approach for Estimating Micronutrient Requirements

In Europe, micronutrient dietary reference values have been established by (inter)national committees of experts and are used by public health policy decision-makers to monitor and assess the adequacy of diets within population groups. The approaches used to derive dietary reference values (including average requirements) vary considerably across countries, and so far no evidence-based reason has been identified for this variation. Nutrient requirements are traditionally based on the minimum amount of a nutrient needed by an individual to avoid deficiency, and is defined by the bodys physiological needs. Alternatively the requirement can be defined as the intake at which health is optimal, including the prevention of chronic diet-related diseases. Both approaches are confronted with many challenges (e. g., bioavailability, inter and intra-individual variability). EURRECA has derived a transparent approach for the quantitative integration of evidence on Intake-Status-Health associations and/or Factorial approach (including bioavailability) estimates. To facilitate the derivation of dietary reference values, EURopean micronutrient RECommendations Aligned (EURRECA) is developing a process flow chart to guide nutrient requirement-setting bodies through the process of setting dietary reference values, which aims to facilitate the scientific alignment of deriving these values.

Folate Intake and Markers of Folate Status in Women of Reproductive Age, Pregnant and Lactating Women: A Meta-Analysis

Background. Pregnant and breastfeeding women are at risk for folate deficiency. Folate supplementation has been shown to be associated with enhanced markers of folate status. However, dose-response analyses for adult women are still lacking. Objective. To assess the dose-response relationship between total folate intake (folic acid plus dietary folate) and markers of folate status (plasma/serum folate, red blood cell folate, and plasma homocysteine); to evaluate potential differences between women in childbearing age, pregnant and lactating women. Methods. Electronic literature searches were carried out on three databases until February 2010. The overall pooled regression coefficient (β) and SE(β) were calculated using meta-analysis on a double-log scale. Results. The majority of data was based on nonpregnant, nonlactating women in childbearingage. The pooled estimate of the relationship between folate intake and serum/plasma folate was 0.56 (95% CI = 0.40–0.72, P < 0.00001); that is, the doubling of folate intake increases the folate level in serum/plasma by 47%. For red blood cell folate, the pooled-effect estimate was 0.30 (95% CI = 0.22–0.38, P < 0.00001), that is, +23% for doubling intake. For plasma-homocysteine it was –0.10 (95% = –0.17 to –0.04, P = 0.001), that is, –7% for doubling the intake. Associations tended to be weaker in pregnant and lactating women. Conclusion. Significant relationships between folate intake and serum/plasma folate, red blood cell folate, and plasma homocysteine were quantified. This dose-response methodology may be applied for setting requirements for women in childbearing age, as well as for pregnant and lactating women.

Non-linear associations between serum 25-OH vitamin D and indices of arterial stiffness and arteriosclerosis in an older population

BACKGROUND several studies have been pointing towards a non-linear relationship between serum 25(OH)D and cardiovascular disease. Next to vitamin D deficiency, also higher levels of 25(OH)D have been reported to be associated with increased cardiovascular risk. We aimed to investigate the nature of the relationship between serum 25(OH)D and measures of arterial stiffness and arteriosclerosis in an elderly population. DESIGN cross-sectional. SETTING/SUBJECTS a subgroup of the B-PROOF study was included to determine associations between serum 25(OH)D and arterial stiffness and atherosclerosis (n = 567, 57% male, age 72.6 ± 5.6 years, mean serum 25(OH)D 54.6 ± 24.1 nmol/l). METHODS carotid intima media thickness (IMT) was assessed using ultrasonography and pulse wave velocity (PWV) was determined with applanation tonometry. Associations were tested using multivariable restricted cubic spline functions and stratified linear regression analysis. RESULTS the associations between serum 25(OH)D and carotid IMT or PWV were non-linear. Spline functions demonstrated a difference between 25(OH)D deficient and sufficient individuals. In serum 25(OH)D sufficient participants (≥50 nmol/l; n = 287), a positive association with IMT and serum 25(OH)D was present (β 1.24; 95%CI [0.002; 2.473]). PWV levels were slightly lower in vitamin D deficient individuals, but the association with 25(OH)D was not significant. CONCLUSION our study demonstrates that associations of serum 25(OH)D and PWV and IMT in an elderly population are not linear. In particular from serum 25(OH)D levels of 50 nmol/l and up, there is a slight increase of IMT with increasing 25(OH)D levels.