Reference values for serum levels of vitamin B12 and folic acid in a population-based sample of adults between 35 and 80 years of age

Can vitamins improve periodontal wound healing/regeneration?

Periodontitis is a complex inflammatory disorder of the tooth supporting structures, associated with microbial dysbiosis, and linked to a number if systemic conditions. Untreated it can result in an irreversible damage to the periodontal structures and eventually teeth loss. Regeneration of the lost periodontium requires an orchestration of a number of biological events on cellular and molecular level. In this context, a set of vitamins have been advocated, relying their beneficial physiological effects, to endorse the biological regenerative events of the periodontium on cellular and molecular levels. The aim of the present article is to elaborate on the question whether or not vitamins improve wound healing/regeneration, summarizing the current evidence from in vitro, animal and clinical studies, thereby shedding light on the knowledge gap in this field and highlighting future research needs. Although the present review demonstrates the current heterogeneity in the available evidence and knowledge gaps, findings suggest that vitamins, especially A, B, E, and CoQ10, as well as vitamin combinations, could exert positive attributes on the periodontal outcomes in adjunct to surgical or nonsurgical periodontal therapy.

Vitamin B12 reference intervals on Beckman, Roche and Siemens analytical platforms

BACKGROUND

Vitamin B12 status is assessed primarily by measuring total serum B12 using competitive binding methods. The lack of availability of a standard material and high-level reference measurement procedure affect the trueness of B12 results; this results in variation between methods. This study aimed to determine the reference intervals for vitamin B12 on three routine analytical platforms.

METHOD

A prospective reference population of healthy individuals was recruited according to the IFCC CRIDL criteria. Vitamin B12 samples were measured on Roche, Beckman and Siemens analytical platforms.

RESULTS

In total, 300 adult subjects were recruited; the central 95th centile values for B12 for Roche (190-678 ng/mL) and Siemens (181-562 ng/mL) analytical platforms were in a close agreement. Beckman DXi, however, showed a significantly lower reference limit (110-562 ng/mL). All reference intervals are in keeping with previously published data but some are not in agreement with manufacturer provided reference interval.

CONCLUSION

As the quality of the reference intervals plays a significant role in clinical outcome, it is of great importance that laboratories use a method-specific reference interval and if possible, locally derived reference intervals until further method standardization occurs.

Reference intervals for plasma vitamin B12 and plasma/serum methylmalonic acid in Danish children, adults and elderly

BACKGROUND

Plasma/serum vitamin B12 (B12) is often used to screen for B12 deficiency complemented with analysis of methylmalonic acid (MMA) in case of low B12. The concentration of both analytes likely depends on age, and we, therefore, aimed at establishing 95% age-adjusted reference intervals (RIs) for plasma B12 and serum/plasma MMA in the Danish population.

METHODS

We collected and analysed blood samples from healthy children, adults, and elderly individuals and extracted routine clinical B12 and MMA results to establish RIs. We also evaluated the association between matching B12 and MMA results.

RESULTS

We suggest the following RIs for plasma B12 and plasma/serum MMA, respectively. 0-<1 year: 180-1400 pmol/L, 0.10-1.25 µmol/L; 1-<11 years: 260-1200 pmol/L, 0.10-0.30 µmol/L; 12-<18 years: 200-800 pmol/L, 0.10-0.35 µmol/L; 18-<65 years: 200-600 pmol/L, 0.10-0.40 µmol/L; 65 + years: 200-600 pmol/L, 0.12-0.46 µmol/L. Finally, the proportion of patients with elevated MMA differed between age groups independently of B12 and was highest in children.

CONCLUSION

We propose new age-adjusted RIs for B12 and MMA and suggest that age-dependent cut-off values should be implemented if plasma B12 is used to screen for B12 deficiency.

Do implant-supported prostheses affect bioavailability of nutrients of complete and partially edentulous patients? A systematic review with meta-analysis

BACKGROUND & AIMS

Debate still exists about the impact of dental implant-supported prostheses on nutritional status of partially and complete edentulous patients. This review aims to answer the focused question: "Do complete and partial edentulous patients, using implant-supported prostheses, present better nutritional and masticatory functions when compared to those using conventional rehabilitations?". A possible cause-effect relationship between masticatory improvements and nutritional gain was also evaluated.

METHODS

Literature search included 6 databases (PubMed/Medline, Embase, LILACS, Scopus, Web of Science, and The Cochrane Library - CENTRAL), grey literature (Google Scholar, Proquest Dissertations and Thesis and Open Grey databases) and manual search (last update June 2020), without language, publication time and follow-up restrictions. We included only studies evaluating both masticatory and nutritional outcomes. The PICO question comprised complete and partial edentulous patients (Population), submitted to implant-supported prostheses (Intervention), in comparison to conventional dental prosthetic rehabilitation, evaluating masticatory function and nutrition parameters (outcomes). Risk of bias was assessed by using Cochrane Collaboration's tool (randomized clinical trials), Joanna Briggs Institute critical appraisal checklist (paired clinical trials), and Meta-Analysis of Statistics Assessment and Review Instrument" (JBI - MAStARI) critical appraisal tools (cohort studies). All meta-analyses were conducted at 5% level of significance. This report followed the PRISMA guidelines. (Review registration PROSPERO - CRD42019135744).

RESULTS

We identified 1199 articles while searching databases. Fourteen articles met eligibility criteria, including 817 prostheses installed in 660 patients (mean age = 66.8 years-old). Patients wearing implant overdentures (IOD) presented better masticatory function in comparison to conventional complete denture (CD) wearers (p < 0.05). However, bioavailability of several nutrients remained within the same range, except for serum folate that was lower in IOD patients after 6 (mean difference 3.51 nmol/L; p = 0.01) and 12 months of rehabilitation (mean difference 3.69 nmol/L; p = 0.003). When comparing the effects of CD and IOD rehabilitations along time (for the same patient), serum albumin and vitamin B12 levels also decreased for both groups after 12 months-follow-up, but still within the reference range. The additional retention of the implants did not interfere in body weight, but reduced the risk of malnutrition (using the Mini Nutritional Assessment). Implant-supported partial prostheses also improved mastication in comparison to the conventional ones, increasing short-term daily intake of carbohydrates, protein, calcium, fiber, and iron, whereas decreasing the consumption of cholesterol. However, no long-term changes on bioavailability of most nutrients were observed, expect for a slight increase in ferritin and cholinesterase, and a small reduction in folate and Vitamin A.

CONCLUSION

Current evidence indicates significant masticatory improvements for dental fixed implant-supported prostheses in comparison to conventional removable prostheses. However, bioavailability remained stable for most of the nutrients, especially for complete edentulous patients. These results indicate the importance of a multidisciplinary approach during oral rehabilitation (nutrient specialist), in order to enhance food choices and promote health benefits to the patients.

Dynamics and interactions of cobalamin and folate status during advanced aging - a longitudinal study in a community-dwelling cohort with multiple follow-ups

BACKGROUND

Older people are reported to be prone to imbalances between cobalamin and folate status with possible adverse effects on health. This longitudinal study investigates dynamics and interactions of cobalamin and folate status in a cohort of community-dwelling older adults by considering possible influencing factors.

METHODS

In total, 332 subjects ≥ 60 years were investigated over a mean observation period of 12 years. Data collection included serum cobalamin, folate and creatinine, dietary intakes of cobalamin, folate and alcohol, use of supplements, body composition, smoking behavior, and diseases. Linear mixed-effects models with repeated measurements were used to investigate the influence of variables on serum cobalamin and folate.

RESULTS

At baseline, median cobalamin intake exceeded the dietary reference value (DRV), while median folate intake was considerably below DRV. In most subjects, serum concentrations of both vitamins were within reference ranges. For serum cobalamin, apart from supplement use (Parameter estimate [95% confidence interval]: 130.17 [53.32, 207.01]), the main positive predictor was serum folate (4.63 [2.64, 6.62]). For serum folate, serum creatinine (10.85 [4.85, 16.86]), use of supplements (7.86 [5.05, 10.67]), serum cobalamin (0.01 [< 0.01, 0.01]), and dietary folate intake (0.02 [0.01, 0.03]) were positive predictors. No main effects of age, sex, body composition, alcohol intake or smoking were found after adjusting for simultaneous inference.

CONCLUSIONS

Advancing age, per se, is no risk factor for a decline in serum concentrations of cobalamin or folate in subjects ≥ 60 years. Suboptimal folate intake may limit the function of folate regarding the supply of methyl groups for methylation of cobalamin and subsequent creatine biosynthesis. The positive association of serum creatinine with folate deserves further exploration with regard to its possible relevance for maintaining energy dependent functional integrity in the course of ageing.

Determination of indirect reference intervals of vitamin B12 for outpatients admitted to primary healthcare centers

Background

Vitamin B12 deficiency is still an important nutritional problem worldwide. There is no consensus on the reference intervals (RIs) for vitamin B12. In order to establish vitamin B12 RIs, we used the database obtained from a primary healthcare organization and estimated region-specific intervals.

Methods

Vitamin B12 results were collected from our laboratory information system (LIS) between January 2014 and July 2014. We excluded the results of the individuals who had megaloblastic and microcytic anemia. After outlier detection and exclusion, we estimated the RIs of the “1–12, 13–18, 19–64 and 65 +” age groups according to the International Federation of Clinical Chemistry (IFCC) method. Statistical differences were examined between groups.

Results

The reference limits and 90% confidence intervals (CIs) (n = 14,748, 3790 male, age: 1–96; 10,958 female, age: 1–115) were estimated with 90% CIs as 106 (104–107)–393 (391–395) pmol/L. We also estimated the reference limits of the “1–12, 13–18, 19–64 and 65 +” age groups to be 127–459, 108–398, 106–384 and 104–426 pmol/L, respectively. There was no difference between genders in all age groups.

Conclusions

Both the lower and upper limits of the estimated RIs were found to be lower than the reference limits recommended by the manufacturer. Our findings revealed that the RIs of vitamin B12 should be given for the “1–12, 13–18, 19–64 and 65 +” age groups separately. The big data obtained from laboratories should be used for the determination of its population health status. As our population is composed of outpatients, the estimated vitamin B12 RIs may establish the basic information for the examination of our population for vitamin B12 deficiency.

Methotrexate Affects Cerebrospinal Fluid Folate and Tau Levels and Induces Late Cognitive Deficits in Mice

Intravenous and/or intrathecal administration of the anti-folate drug methotrexate is a common chemotherapeutic procedure in childhood leukemia. Therapeutic and prophylactic efficacy of these procedures notwithstanding, the occurrence of late adverse effects remains a cause of clinical concern in leukemia survivors. We propose an experimental mouse model to mimic the impact of methotrexate exposure on brain biochemistry and cell proliferation, as well as behavioral and neurocognitive functioning at adult age. Female C57Bl6/J mouse pups received saline or methotrexate injection (20 mg/kg, i.p.). CSF and serum concentrations of folate metabolites and toxicity makers were analyzed at 4 h, 24 h, and 1 week following injection. Behavioral test battery performance was assessed at adult age (3-4 months). We found acute changes in serum and CSF levels of folate in exposed pups that coincided with increases in CSF Tau, whereas homocysteine in serum and CSF, and CSF levels of pTau were unchanged or remained below detection. In addition, methotrexate injection coincided with diminished hippocampal cell proliferation 1 week after methotrexate injection. At adult age, exposed mice displayed hippocampus-dependent deficits in the Morris water maze, whereas exploration and anxiety-related behaviors were largely unaffected. Particularly during the reference memory (probe) trial after reversal learning, methotrexate-exposed animals were less precise than controls. These findings demonstrate adult neurocognitive sequelae in a mouse model that can be attributed to the biochemical and cellular impact of early-life methotrexate exposure.

Macrocytosis among patients with heroin use disorder

PURPOSE

Few empirical studies have investigated hematological parameters among people with a heroin use disorder. This study explores the prevalence of macrocytosis and associated factors among patients with heroin use disorder who were entering methadone maintenance treatment (MMT) in Taiwan.

PATIENTS AND METHODS

In this cross-sectional study, hematological parameters were measured and the prevalence of macrocytosis was assessed in a sample of 958 patients with a heroin use disorder entering the MMT program at Tsaotun Psychiatric Center in Taiwan. The demographic characteristics, heroin-related issues, other substance use history, and other clinical variables were analyzed. Univariate analysis was used to assess the association of all variables. Multivariable logistic regression was used to identify the relationship between the significant factors and macrocytosis.

RESULTS

The study found that nearly one-fifth (19.5%) of the participants had macrocytosis. Older age, longer duration of heroin use, and more days of alcohol use within the previous month were associated with macrocytosis.

CONCLUSION

We found that concurrent use of alcohol was an important factor related to macrocytosis among people with a heroin use disorder. The prevalence of macrocytosis indicated that alcohol use is common among this population. It is suggested that policies and practices regarding alcohol use should be addressed within methadone maintenance programs.

Predictors of serum cobalamin and its association with homocysteine in community-dwelling older adults

BACKGROUND/OBJECTIVES

This study investigates the predictors of serum cobalamin concentrations in community-dwelling older adults and the relationship between serum cobalamin and plasma homocysteine.

SUBJECTS/METHODS

Serum cobalamin and plasma homocysteine were measured by SimulTRAC-SNB radio assay and HPLC, respectively. Linear multiple regression analyses were performed with cross-sectional data of 352 participants aged 60-90 years to examine (1) the predictors of serum cobalamin and (2) the association between cobalamin and homocysteine status. Age, sex, body composition, diet, supplement use, smoking, serum folate, serum pyridoxal 5´-phosphate, serum creatinine, and selected diseases were considered as potential predicting/confounding factors.

RESULTS

Median values of serum cobalamin, plasma homocysteine, and dietary cobalamin intake were 256 pmol/L, 9.7 µmol/L, and 5.7 µg/day, respectively. In multiple regression analysis, cobalamin intake, sex, body composition, serum creatinine and smoking did not predict serum cobalamin (all P > 0.05). In contrast, age (β = 0.111, P = 0.031), serum folate (β = 0.410, P < 0.001) and diagnosis of chronic inflammatory bowel disease (IBD) (β = 0.101, P = 0.037) were positively and cancer diagnosis (β = -0.142, P = 0.003) was negatively associated with serum cobalamin. The model explained 23% of the variability of serum cobalamin. After exclusion of subjects with IBD/cancer diagnosis and/or vitamin B/multi-vitamin supplementation, only serum folate remained as positive predictor of serum cobalamin (β = 0.407, P < 0.001). Serum cobalamin was positively associated with inverse-transformed plasma homocysteine before (β = 0.298, P < 0.001) and after (β = 0.199, P < 0.001) multiple adjustments.

CONCLUSIONS

Serum folate but not cobalamin intake or age proves to be a main predictor of cobalamin status. Nevertheless, independent of serum folate and other potential confounders, serum cobalamin is inversely associated with plasma homocysteine.

The effect of vitamin B12 and folic acid supplementation on routine haematological parameters in older people: an individual participant data meta-analysis

BACKGROUND/OBJECTIVES

Low vitamin B12 and folate levels in community-dwelling older people are usually corrected with supplements. However, the effect of this supplementation on haematological parameters in older persons is not known. Therefore, we executed a systematic review and individual participant data meta-analysis of randomised placebo-controlled trials (RCTs).

SUBJECTS/METHODS

We performed a systematic search in PubMed, EMBASE, Web of Science, Cochrane and CENTRAL for RCTs published between January 1950 and April 2016, where community-dwelling elderly (60+ years) who were treated with vitamin B12 or folic acid or placebo. The presence of anaemia was not required. We analysed the data on haematological parameters with a two-stage IPD meta-analysis.

RESULTS

We found 494 full papers covering 14 studies. Data were shared by the authors of four RCTs comparing vitamin B12 with placebo (n = 343) and of three RCTs comparing folic acid with placebo (n = 929). We found no effect of vitamin B12 supplementation on haemoglobin (change 0.00 g/dL, 95% CI: -0.19;0.18), and no effect of folic acid supplementation (change -0.09 g/dL, 95% CI: -0.19;0.01). The effects of supplementation on other haematological parameters were similar. The effects did not differ by sex or by age group. Also, no effect was found in a subgroup of patients with anaemia and a subgroup of patients who were treated >4 weeks.

CONCLUSIONS

Evidence on the effects of supplementation of low concentrations of vitamin B12 and folate on haematological parameters in community-dwelling older people is inconclusive. Further research is needed before firm recommendations can be made concerning the supplementation of vitamin B12 and folate.

Dietary intake and biomarker status of folate in Swedish adults

PURPOSE

National data on folate status are missing in Sweden, and regional data indicate folate insufficiency in up to more than 25% of the study populations. The objectives were to determine folate intake and status in the adult Swedish population as well as identifying dietary patterns associated with beneficial folate status.

METHODS

Folate intake was estimated using a web-based 4-d food record in adults aged 18-80 years (n = 1797). Folate status was measured as erythrocyte (n = 282) and plasma folate concentrations (n = 294). Factor analysis was used to derive a dietary pattern associated with a higher folate status.

RESULTS

Median folate intake was 246 µg/day (Q ₁ = 196, Q ₃ = 304, n = 1797) and for women of reproductive age 227 µg/day (Q ₁ = 181, Q ₃ = 282, n = 450). As dietary folate equivalents (DFE), median intake was 257 µg/day (Q ₁ = 201, Q ₃ = 323) and for women of reproductive age 239 µg/day (Q ₁ = 185, Q ₃ = 300). Low blood folate concentrations were found in 2% (erythrocyte concentrations <317 nmol/L) and 4% (plasma concentrations <6.8 nmol/L) of the participants, respectively. None of the women of reproductive age had erythrocyte folate concentrations associated with the lowest risk of neural tube defects. Dietary patterns associated with higher folate status were rich in vegetables, pulses and roots as well as cheese and alcoholic beverages, and low in meat.

CONCLUSIONS

Prevalence of low erythrocyte folate concentrations was low in this population, and estimated dietary intakes are well above average requirement. However, to obtain a folate status optimal for prevention of neural tube defects major dietary changes are required and folic acid supplements recommended prior to conception.

The Role of Folate Transport in Antifolate Drug Action in Trypanosoma brucei

The aim of this study was to identify and characterize mechanisms of resistance to antifolate drugs in African trypanosomes. Genome-wide RNAi library screens were undertaken in bloodstream form Trypanosoma brucei exposed to the antifolates methotrexate and raltitrexed. In conjunction with drug susceptibility and folate transport studies, RNAi knockdown was used to validate the functions of the putative folate transporters. The transport kinetics of folate and methotrexate were further characterized in whole cells. RNA interference target sequencing experiments identified a tandem array of genes encoding a folate transporter family, TbFT1-3, as major contributors to antifolate drug uptake. RNAi knockdown of TbFT1-3 substantially reduced folate transport into trypanosomes and reduced the parasite's susceptibly to the classical antifolates methotrexate and raltitrexed. In contrast, knockdown of TbFT1-3 increased susceptibly to the non-classical antifolates pyrimethamine and nolatrexed. Both folate and methotrexate transport were inhibited by classical antifolates but not by non-classical antifolates or biopterin. Thus, TbFT1-3 mediates the uptake of folate and classical antifolates in trypanosomes, and TbFT1-3 loss-of-function is a mechanism of antifolate drug resistance.

Haematinic deficiency and macrocytosis in middle-aged and older adults

OBJECTIVE

To assess the prevalence and determinants of haematinic deficiency (lack of B12 folate or iron) and macrocytosis in blood from a national population-based study of middle-aged and older adults.

METHODS

A cross-sectional study involving 1,207 adults aged ≥45 years, recruited from a sub-study of the Irish National Survey of Lifestyle Attitudes and Nutrition (SLÁN 2007). Participants completed a health and lifestyle questionnaire and a standard food frequency questionnaire. Non-fasting blood samples were obtained for measurement of full blood count and expert morphological assessment, serum ferritin, soluble transferrin receptor assay (sTfR), B12, folate and coeliac antibodies. Blood samples were also assayed for thyroid function (T4, TSH), liver function, aminotransferase (AST) and gamma-glutamyl transferase (GGT).

RESULTS

The overall prevalence (95% C.I.) of anaemia (Hb <13.5 g/dl men and 11.3 g/dl women) was 4.6% (2.9%-6.4%) in men and 1.0% (0.2%-1.9%) in women. Iron deficiency (ferritin <17 ng/ml men and <11 ng/ml in women) was detected in 6.3% of participants (3.7% in males and 8.7% in females, p<0.001). Based on both low ferritin and raised sTfR (>21 nmol/ml) only 2.3% were iron-deficient. 3.0% and 2.7% were found to have low levels of serum folate (<2.3 ng/ml) and serum B12 (<120 ng/l) respectively. Clinically significant macrocytosis (MCV>99fl) was detected in 8.4% of subjects. Strong, significant and independent associations with macrocytosis were observed for lower social status, current smoking status, moderate to heavy alcohol intake, elevated GGT levels, deficiency of folate and vitamin B12, hypothyroidism and coeliac disease. The population attributable fraction (PAF) for macrocytosis associated with elevated GGT (25.0%) and smoking (24.6%) was higher than for excess alcohol intake (6.3%), folate deficiency (10.5%) or vitamin B12 (3.4%).

CONCLUSIONS

Haematinic deficiency and macrocytosis are common in middle-aged/older adults in Ireland. Macrocytosis is more likely to be attributable to an elevated GGT and smoking than vitamin B12 or folate deficiency.

Menopause and age-driven changes in blood level of fat- and water-soluble vitamins

OBJECTIVE

The purpose of this cross-sectional study was to assess the association of the menopausal transition with changes in vitamins.

METHODS

The study group comprised women aged 17-85 years from the Third National Health and Nutrition Examination Survey (NHANES), which was conducted between 1988 and 1994, and from the NHANES surveys conducted between 1999 and 2006. Menopausal status was defined using the time since the last period, < 2, 2-12, and > 12 months, for the pre-, peri-, and postmenopause, respectively. The data-cleaning technique employing serum follicle stimulating hormone activity resulted in pre-, peri- and postmenopausal samples encompassing the following age brackets: 17-50, 42-51, and 46-85 years. Statistical inferences were analyzed using non-parametric techniques.

RESULTS

Significant increases in vitamin A and vitamin E concentrations across all phases of the menopausal transition were observed. There was a gradual decrease in the vitamin C concentration across all stages of the menopause but a fairly stable concentration of vitamin B12. There was a statistically significant increase in vitamin D between the pre- and postmenopause. Body mass index correlated negatively with serum vitamin concentration in the pre- and postmenopause.

CONCLUSIONS

Vitamin A should be supplemented in postmenopausal women to decrease the risk of bone fracture. The daily diet should be supplemented with vitamin B12, to avoid possible neurological symptoms due to vitamin B12 deficiency, and with vitamin D to decrease the risk of developing secondary hyperparathyroidism. Due to an adverse influence on serum vitamin concentration, body mass index should be monitored in pre- and postmenopausal women.

Relation of body mass index to blood folate and total homocysteine concentrations in Japanese adults

PURPOSE

Plasma folate concentrations are suggested to be negatively associated with body mass index (BMI, kg/m(2)), although these findings are controversial. Our objective was to evaluate the association of BMI with blood folate and total homocysteine (tHcy) concentrations.

METHODS

We measured plasma and erythrocyte folate and plasma tHcy concentrations in 434 healthy adults (343 women and 91 men; mean age of 63.8 ± 10.7 [SD, range 23-88] years), who participated in a 2007 population-based survey in western Japan.

RESULTS

The overall mean plasma and erythrocyte folate and tHcy were 21.6 (±11.0, SD) nmol/L, 844 (±291) nmol/L and 11.6 (±3.9) μmol/L, respectively. The mean BMI was 22.8 (±3.0; 15.6-33.3) kg/m(2), and only 72 subjects (17%) had BMI > 26.0 kg/m(2). Mean plasma folate decreased as BMI increased (p-trend < 0.01), whereas mean erythrocyte folate and plasma tHcy were similar regardless of BMI (p-trends = 0.49 and 0.28, respectively).

CONCLUSION

Our data indicate that the interpretation of plasma folate concentrations to assess folate nutritional status is complicated by BMI, although the impact of BMI on plasma folate was relatively small. It is important to take this association into account for the selection of subjects for future large-scale studies. The mechanism of this inverse association between BMI and plasma folate concentrations should be investigated.

Serum concentrations of vitamin B12 and folate in British male omnivores, vegetarians and vegans: results from a cross-sectional analysis of the EPIC-Oxford cohort study

BACKGROUND/OBJECTIVES

Vegans, and to a lesser extent vegetarians, have low average circulating concentrations of vitamin B12; however, the relation between factors such as age or time on these diets and vitamin B12 concentrations is not clear. The objectives of this study were to investigate differences in serum vitamin B12 and folate concentrations between omnivores, vegetarians and vegans and to ascertain whether vitamin B12 concentrations differed by age and time on the diet.

SUBJECTS/METHODS

A cross-sectional analysis involving 689 men (226 omnivores, 231 vegetarians and 232 vegans) from the European Prospective Investigation into Cancer and Nutrition Oxford cohort.

RESULTS

Mean serum vitamin B12 was highest among omnivores (281, 95% CI: 270-292 pmol/l), intermediate among vegetarians (182, 95% CI: 175-189 pmol/l) and lowest among vegans (122, 95% CI: 117-127 pmol/l). In all, 52% of vegans, 7% of vegetarians and one omnivore were classified as vitamin B12 deficient (defined as serum vitamin B12 <118 pmol/l). There was no significant association between age or duration of adherence to a vegetarian or a vegan diet and serum vitamin B12. In contrast, folate concentrations were highest among vegans, intermediate among vegetarians and lowest among omnivores, but only two men (both omnivores) were categorized as folate deficient (defined as serum folate <6.3 nmol/l).

CONCLUSION

Vegans have lower vitamin B12 concentrations, but higher folate concentrations, than vegetarians and omnivores. Half of the vegans were categorized as vitamin B12 deficient and would be expected to have a higher risk of developing clinical symptoms related to vitamin B12 deficiency.

Cognitive and mood effects in healthy children during 12 weeks' supplementation with multi-vitamin/minerals

Adequate levels of vitamins and minerals are essential for optimal neural functioning. A high proportion of individuals, including children, suffer from deficiencies in one or more vitamins or minerals. This study investigated whether daily supplementation with vitamins/minerals could modulate cognitive performance and mood in healthy children. In this randomised, double-blind, placebo-controlled, parallel groups investigation, eighty-one healthy children aged from 8 to 14 years underwent laboratory assessments of their cognitive performance and mood pre-dose and at 1 and 3 h post-dose on the first and last days of 12 weeks' supplementation with a commercially available vitamins/mineral product (Pharmaton Kiddi). Interim assessments were also completed at home after 4 and 8 weeks at 3 h post-dose. Each assessment comprised completion of a cognitive battery, delivered over the Internet, which included tasks assessing mood and the speed and accuracy of attention and aspects of memory (secondary, semantic and spatial working memory). The vitamin/mineral group performed more accurately on two attention tasks: 'Arrows' choice reaction time task at 4 and 8 weeks; 'Arrow Flankers' choice reaction time task at 4, 8 and 12 weeks. A single task outcome (Picture Recognition errors) evinced significant decrements at 12 weeks. Mood was not modulated in any interpretable manner. Whilst it is possible that the significant improvements following treatment were due to non-significant numerical differences in performance at baseline, these results would seem to suggest that vitamin/mineral supplementation has the potential to improve brain function in healthy children. This proposition requires further investigation.

Long-term use of proton pump inhibitors and vitamin B12 status in elderly individuals

BACKGROUND

Some studies have shown that short-term use of proton pump inhibitors decreases the absorption of vitamin B12, but the results of studies into long-term proton pump inhibitor use and vitamin B12 deficiency are inconsistent.

AIM

To investigate whether long-term proton pump inhibitor use is associated with an abnormal vitamin B12 status in elderly individuals.

METHODS

One hundred and twenty-five long-term (>3, years) proton pump inhibitor users aged 65, years and above were recruited from general practices. Their 125 partners (who did not use proton pump inhibitors) served as the reference group. Vitamin B12 status was determined by serum levels of vitamin B12 and homocysteine, and mean corpuscular volume.

RESULTS

No differences in mean vitamin B12 levels were observed between the long-term proton pump inhibitor users and their partners [345 (s.d. 126), pm vs. 339 (s.d. 133), pm, P, =, 0.73], even after adjustment for age, gender, Helicobacter pylori status and C-reactive protein levels (P, =, 0.87). Four proton pump inhibitor users and three partners had vitamin B12 levels <150, pm (3% vs. 2%, P, =, 1.00). No differences between the groups were observed in homocysteine levels and mean corpuscular volume.

CONCLUSIONS

No association between long-term proton pump inhibitor use and vitamin B12 status was observed. Regular testing for low vitamin B12 levels in elderly patients on long-term treatment with proton pump inhibitors is therefore not recommended.

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.

Nutritional status in pregnant adolescents: a systematic review of biochemical markers

Adolescent pregnancy is a major public health challenge for many industrialized countries and is associated with significant medical, nutritional, social and economic risk for mothers and their infants. Despite this, relatively little is known about the nutritional status of this population. The aim of this paper was to conduct a systematic review of the current evidence relating to the biochemical markers of nutritional status of pregnant adolescents living in industrialized countries. Six papers were identified that fulfilled the inclusion criteria, the majority of which were conducted in the United States. The studies were of variable quality and most failed to control for potential confounders which may have strongly influenced the findings. Due to limited research, conclusions cannot be drawn about the zinc and calcium status of pregnant adolescents, and data on folate and vitamin B(12) status appeared conflicting. There was some consensus among studies, however, to suggest that indicators of anaemia and iron status were compromised in pregnant adolescents, particularly during the third trimester of pregnancy. Chronological age did not appear to influence nutritional status, although there was some evidence to suggest that increasing gynaecologic age may positively influence plasma ferritin levels. Current research is limited by sampling and measurement bias, and research is urgently required to address these limitations. Further consideration should also be made of the influence of the role of socio-economic support on pregnant adolescents' nutritional status. The achievement of improved nutrition in pregnancy among adolescents requires multidisciplinary collaborations of adolescent healthcare providers, academics, professional organizations, policymakers, industry and service users. Only once this is achieved can adolescent nutrition, and adolescent nutrition in pregnancy, be significantly and sustainably optimized.

Memory Processes, Aging, Cognitive Decline, and Neurodegenerative Diseases

This paper presents four domains of markers that have been found to predict later cognitive impairment and neurodegenerative disease. These four domains are (1) data patterns of memory performance, (2) cardiovascular factors, (3) genetic markers, and (4) brain activity. The critical features of each domain are illustrated with data from the longitudinal Betula Study on memory, aging, and health ( Nilsson et al., 1997 ; Nilsson et al., 2004 ). Up to now, early signs regarding these domains have been examined one by one and it has been found that they are associated with later cognitive impairment and neurodegenerative disease. However, it was also found that each marker accounts for only a very small part of the total variance, implying that single markers should not be used as predictors for cognitive decline or neurodegenerative disease. It is discussed whether modeling and simulations should be used as tools to combine markers at different levels to increase the amount of explained variance.

Plasma folate, vitamin B12, and homocysteine and prostate cancer risk: A prospective study

The role of folate metabolism in cancer development is a topic of much current interest, with maintenance of adequate folate status tending to show a protective effect. Aberrant methylation, primarily hypermethylation of certain genes including tumor suppressors, has been implicated in prostate cancer development. Folate, vitamin B12 and homocysteine are essential for methyl group metabolism and thus also for DNA methylation. We related plasma levels of these factors to prostate cancer risk in a prospective study of 254 case subjects and 514 matched control subjects. Increasing plasma levels of folate and vitamin B12 were statistically significantly associated with increased prostate cancer risk, with an odds ratio of 1.60 (95% CI = 1.03-2.49; p(trend) = 0.02) for folate and 2.63 (95% CI = 1.61-4.29; p(trend) < 0.001) for vitamin B12 for highest vs. lowest quartile. Increasing plasma homocysteine levels were associated with a reduced risk of borderline significance (OR = 0.67; 95% CI = 0.43-1.04; p(trend) = 0.08). After adjustment for the other 2 plasma variables, body mass index and smoking, a statistically significant increased risk remained only for vitamin B12 (OR = 2.96; 95% CI = 1.58-5.55; p(trend) = 0.001). Adjusted OR for folate and homocysteine were 1.30 (95% CI = 0.74-2.24; p(trend) = 0.17) and 0.91 (95% CI = 0.51-1.58; p(trend) = 0.60), respectively. Our results suggest that factors contributing to folate status are not protective against prostate cancer. On the contrary, vitamin B12, associated with an up to 3-fold increase in risk, and possibly also folate, may even stimulate prostate cancer development. These findings are novel and should be explored further in future studies.

Cobalamin status and its biochemical markers methylmalonic acid and homocysteine in different age groups from 4 days to 19 years

BACKGROUND

Recent data indicate that cobalamin and folate status, including the metabolic markers methylmalonic acid (MMA) and total homocysteine (tHcy), undergo marked changes during childhood, particularly during the first year.

METHODS

Serum cobalamin, serum and whole-blood folate, and plasma MMA and tHcy were determined in a cross-sectional study of 700 children, ages 4 days to 19 years.

RESULTS

During the first 6 months, serum cobalamin was lower than and plasma MMA, tHcy, and serum folate were higher than the concentrations detected in the other age groups. In infants 6 weeks to 6 months of age, median MMA and tHcy concentrations were >0.78 and >75 micro mol/L, respectively. In older children (>6 months), serum cobalamin peaked at 3-7 years and then decreased, median plasma MMA remained low (<0.26 micro mol/L), median plasma tHcy was low (<6 micro mol/L) and increased from the age of 7 years on, and serum folate gradually decreased. Plasma MMA was inversely associated with cobalamin (r = -0.4) in both age groups, but across the whole range of cobalamin concentrations, MMA was markedly higher in infants (< or =6 months) than in older children. Plasma tHcy showed a strong negative correlation to cobalamin (r = -0.52) but not to serum folate in infants < or =6 months. In older children, tHcy showed the expected association with both cobalamin (r = -0.48) and folate (r = -0.51).

CONCLUSIONS

In infants 6 weeks to 6 months, concentrations of the metabolic markers MMA and tHcy were higher than in the other age groups and strongly correlated to cobalamin, whereas in older children, both makers showed correlations to cobalamin and folate concentrations documented in adults. Whether this metabolic profile in infants is explained by impaired cobalamin status, which in turn may have long-term effects on psychomotor development, remains to be addressed in intervention studies.