Vitamin B12 in health and disease

Vitamins and type 2 diabetes mellitus

The present review evaluates the relationship between type 2 diabetes mellitus and individual or combined vitamins. Antioxidant vitamins A, C and E are found decreased in diabetic subjects, possibly due to an increased need to control the excessive oxidative stress produced by abnormalities in glucose metabolism. On the other hand, retinol binding protein exerts a modulating effect, as it has adipokine functions. With respect to the B group vitamins, thiamin, pyridoxine and biotin have been found decreased but the mechanisms are not clear, however supplementation has shown some improvement of the metabolic control in diabetic patients. The absorption of folic acid and vitamin B12 is importantly decreased by the prolongued use of metformin, which is the first choice drug in uncomplicated diabetes, thus these two nutrients have been found deficient in the disease and most probably need to be supplemented regularly. On the other hand, vitamin D is considered a risk factor for the development of diabetes as well as its complications, particularly cardiovascular ones. Although some studies have found an association of vitamin K intake with glucose metabolism further research is needed. Studies on the use of multivitamin supplements have shown unconclusive results. After reviewing the evidence, no real recommendation on the use of vitamin supplements in type 2 diabetes mellitus can be issued, however patients using metformin during prolongued periods may need folic acid and vitamin B12.

Paternal intake of folate and vitamins B6 and B12 before conception and risk of childhood acute lymphoblastic leukemia

PURPOSE

We investigated whether paternal dietary intake of folate before conception is associated with the risk of childhood acute lymphoblastic leukemia (ALL) in a nationwide case-control study.

METHODS

Data on dietary folate intake during the 6 months before the child's conception were collected from 285 case fathers and 595 control fathers using a dietary questionnaire. Nutrient intake was quantified using a customized computer software package based on Australian food composition databases. Data on folate intake were analyzed using unconditional logistic regression, adjusting for study-matching variables, total energy, and potentially confounding variables. In a subset of 229 cases and 420 controls, data on vitamin B6 and vitamin B12 intake were also analyzed.

RESULTS

No consistent associations were seen with paternal dietary intake of folate or vitamin B6. Higher levels of paternal dietary vitamin B12 were appeared to be associated with an increased risk of childhood ALL, with those in the highest tertile of consumption having an OR of 1.51 (0.97, 2.36). The use of supplements containing folate and vitamins B6 or B12 was rare.

CONCLUSIONS

We did not find any biologically plausible evidence that paternal nutrition in the period leading up to conception was associated with childhood ALL. Our finding for vitamin B12 may be a chance finding, given the number of analyses performed, or be attributable to participation bias because parents with a tertiary education had the lowest level of B12 intake and tertiary education was more common among control than case parents.

Micronutrient status in female university students: iron, zinc, copper, selenium, vitamin B12 and folate

Young women are at an increased risk of micronutrient deficiencies, particularly due to higher micronutrient requirements during childbearing years and multiple food group avoidances. The objective of this study was to investigate biomarkers of particular micronutrients in apparently healthy young women. Female students (n = 308; age range 18-35 year; Body Mass Index 21.5 ± 2.8 kg/m2; mean ± SD) were recruited to participate in a cross-sectional study. Blood samples were obtained from participants in the fasted state and analysed for biomarkers of iron status, vitamin B12, folate, homocysteine, selenium, zinc, and copper. The results show iron deficiency anaemia, unspecified anaemia, and hypoferritinemia in 3%, 7% and 33.9% of participants, respectively. Low vitamin B12 concentrations (<120 pmol/L) were found in 11.3% of participants, while 4.7% showed sub-clinical deficiency based on serum methylmalonic acid concentrations >0.34 μmol/L. Folate concentrations below the reference range were observed in 1.7% (serum) or 1% (erythrocytes) of participants, and 99.7% of the participant had erythrocyte-folate concentrations >300 nmol/L. Serum zinc concentrations <10.7 μmol/L were observed in 2% of participants. Serum copper and selenium concentrations were below the reference range in 23% and 11% of participants, respectively. Micronutrient deficiencies including iron and vitamin B12, and apparent excess of folate are present in educated Australian female students of childbearing age, including those studying nutrition. The effects of dietary behaviours and food choices on markers of micronutrient status require further investigation.

Long-term proton pump inhibitor therapy and falls and fractures in elderly women: a prospective cohort study

Proton pump inhibitors (PPIs) are widely used in the elderly. Recent studies have suggested that long-term PPI therapy is associated with fractures in the elderly, however the mechanism remains unknown. We investigated the association between long-term PPI therapy ≥1 year and fracture risk factors including bone structure, falls, and balance-related function in a post hoc analysis of a longitudinal population-based prospective cohort of elderly postmenopausal women and replicated the findings in a second prospective study of falling in elderly postmenopausal women. Long-term PPI therapy was associated with increased risk of falls and fracture-related hospitalizations; adjusted odds ratio (AOR) 2.17; 95% CI, 1.25-3.77; p = 0.006 and 1.95; 95% CI, 1.20-3.16; p = 0.007, respectively. In the replication study, long-term PPI use was associated with an increased risk of self-reported falling; AOR, 1.51; 95% CI, 1.00-2.27; p = 0.049. No association of long-term PPI therapy with bone structure was observed; however, questionnaire-assessed falls-associated metrics such as limiting outdoor activity (p = 0.002) and indoor activity (p = 0.001) due to fear of falling, dizziness (p < 0.001) and numbness of feet (p = 0.017) and objective clinical measurement such as Timed Up and Go (p = 0.002) and Romberg eyes closed (p = 0.025) tests were all significantly impaired in long-term PPI users. Long-term PPI users were also more likely to have low vitamin B12 levels than non-users (50% versus 21%, p = 0.003). In conclusion, similar to previous studies, we identified an increased fracture risk in subjects on long-term PPI therapy. This increase in fracture risk in elderly women, already at high risk of fracture, appears to be mediated via increased falls risk and falling rather than impaired bone structure and should be carefully considered when prescribing long-term PPI therapy.

Impact of personalized diet and probiotic supplementation on inflammation, nutritional parameters and intestinal microbiota - The "RISTOMED project": Randomized controlled trial in healthy older people

OBJECTIVES

To assess the impact of a personalized diet, with or without addition of VSL#3 preparation, on biomarkers of inflammation, nutrition, oxidative stress and intestinal microbiota in 62 healthy persons aged 65-85 years.

DESIGN

Open label, randomized, multicenter study.

PRIMARY ENDPOINT

High-sensitivity C-reactive protein.

SETTING

Community.

INTERVENTIONS

Eight week web-based dietary advice (RISTOMED platform) alone or with supplementation of VSL#3 (2 capsules per day). The RISTOMED diet was optimized to reduce inflammation and oxidative stress.

MEASUREMENTS

Blood and stool samples were collected on days 1 and 56.

RESULTS

Diet alone reduced ESR (p = 0.02), plasma levels of cholesterol (p < 0.01) and glucose (p = 0.03). Addition of VSL#3 reduced ESR (p = 0.05) and improved folate (p = 0.007), vitamin B12 (p = 0.001) and homocysteine (p < 0.001) plasma levels. Neither intervention demonstrated any further effects on inflammation. Subgroup analysis showed 40 participants without signs of low-grade inflammation (hsCRP<3 mg/l, subgroup 1) and 21 participants with low-grade inflammation at baseline (hsCRP≥3 mg/l, subgroup 2). In subgroup 2 addition of VSL#3 increased bifidobacteria (p = 0.005) in more participants and improved both folate (p = 0.015) and vitamin B12 (p = 0.035) levels compared with subgroup 1. The increases were positively correlated to the change in the bifidobacteria concentration for folate (p = 0.023) and vitamin B12 (p = 0.001). As expected change in homocysteine correlated negatively to change in folate (r = -0.629, p = 0.002) and vitamin B12 (r = -0.482, p = 0.026).

CONCLUSIONS

Addition of VSL#3 increased bifidobacteria and supported adequate folate and vitamin B12 concentrations in subjects with low-grade inflammation. Decrease in homocysteine with VSL#3 was clinically relevant. suggesting protective potentials for aging-associated conditions, e.g. cardiovascular or neurological diseases. ClinicalTrials.gov: NCT01069445-NCT01179789.

Treatment of vitamin B12 deficiency-methylcobalamine? Cyancobalamine? Hydroxocobalamin?-clearing the confusion

Vitamin B12 (cyancobalamin, Cbl) has two active co-enzyme forms, methylcobalamin (MeCbl) and adenosylcobalamin (AdCbl). There has been a paradigm shift in the treatment of vitamin B12 deficiency such that MeCbl is being extensively used and promoted. This is despite the fact that both MeCbl and AdCbl are essential and have distinct metabolic fates and functions. MeCbl is primarily involved along with folate in hematopiesis and development of the brain during childhood. Whereas deficiency of AdCbl disturbs the carbohydrate, fat and amino-acid metabolism, and hence interferes with the formation of myelin. Thereby, it is important to treat vitamin B12 deficiency with a combination of MeCbl and AdCbl or hydroxocobalamin or Cbl. Regarding the route, it has been proved that the oral route is comparable to the intramuscular route for rectifying vitamin B12 deficiency.

Homocysteine, cysteine, folate and vitamin B₁₂ status in type 2 diabetic patients with chronic kidney disease

BACKGROUND

Hyperhomocysteinemia (hHcy) is a risk factor in the progression of chronic kidney disease (CKD). In type 2 diabetes (T2D), hHcy is strongly associated with increased risk of cardiovascular disease. Vitamin B12 and folic acid supplementation have been reported to lower homocysteine (tHcy) levels, but no data on plasma tHcy, cysteine (Cys), folate and vitamin B12 levels in T2D-CKD patients are reported.

PROCEDURES

tHcy and Cys levels were analyzed in 178 T2D-CKD patients by high performance liquid chromatography (HPLC) with fluorescence detection. In addition, we determined folate and vitamin B12 levels using a chemiluminescence method.

RESULTS

tHcy and Cys levels were increased in T2D patients, and this rise positively correlated with the CKD stage (P < 0.001). Folate levels were comparable to controls at various CKD stages, whereas vitamin B12 levels were lower, except at stage IV. We did not find any correlation between B-vitamins and levels of tHcy and Cys, regardless of the CKD stage.

CONCLUSIONS

This is the first study reporting tHcy, Cys and B-vitamins status in T2D-CKD patients. Although limited to our cohort of 178 patients, our findings could be helpful in clarifying the conflicting literature regarding B-vitamins supplementation. Further studies are necessary before any Hcy-lowering therapy can be safely established in T2D-CKD subjects.

Inborn errors of metabolism underlying primary immunodeficiencies

A number of inborn errors of metabolism (IEM) have been shown to result in predominantly immunologic phenotypes, manifesting in part as inborn errors of immunity. These phenotypes are mostly caused by defects that affect the (i) quality or quantity of essential structural building blocks (e.g., nucleic acids, and amino acids), (ii) cellular energy economy (e.g., glucose metabolism), (iii) post-translational protein modification (e.g., glycosylation) or (iv) mitochondrial function. Presenting as multisystemic defects, they also affect innate or adaptive immunity, or both, and display various types of immune dysregulation. Specific and potentially curative therapies are available for some of these diseases, whereas targeted treatments capable of inducing clinical remission are available for others. We will herein review the pathogenesis, diagnosis, and treatment of primary immunodeficiencies (PIDs) due to underlying metabolic disorders.

A dodecylamine derivative of cyanocobalamin potently inhibits the activities of cobalamin-dependent methylmalonyl-CoA mutase and methionine synthase of Caenorhabditis elegans

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CN-Cbl dodecylamine, a derivative of cyanocobalamin, was absorbed by C. elegans.

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CN-Cbl dodecylamine decreased activities of cobalamin-dependent enzymes.

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CN-Cbl dodecylamine induced cobalamin deficiency in C. elegans.

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CN-Cbl dodecylamine acts as an inhibitor of cobalamin-dependent enzymes.

In this study, we showed that cyanocobalamin dodecylamine, a ribose 5′-carbamate derivative of cyanocobalamin, was absorbed and accumulated to significant levels by Caenorhabditis elegans and was not further metabolized. The levels of methylmalonic acid and homocysteine, which serve as indicators of cobalamin deficiency, were significantly increased in C. elegans treated with the dodecylamine derivative, indicating severe cobalamin deficiency. Kinetic studies show that the affinity of the cyanocobalamin dodecylamine derivative was greater for two cobalamin-dependent enzymes, methylmalonyl-CoA mutase and methionine synthase, compared with their respective coenzymes, suggesting that the dodecylamine derivative inactivated these enzymes. The dodecylamine derivative did not affect the levels of mRNAs encoding these enzymes or those of other proteins involved in intercellular cobalamin metabolism, including methylmalonyl-CoA mutase (mmcm-1), methylmalonic acidemia cobalamin A complementation group (mmaa-1), methylmalonic aciduria cblC type (cblc-1), and methionine synthase reductase (mtrr-1). In contrast, the level of the mRNAs encoding cob(I)alamin adenosyltransferase (mmab-1) was increased significantly and identical to that of cobalamin-deficient C. elegans. These results indicate that the cyanocobalamin-dodecylamine derivative acts as a potent inhibitor of cobalamin-dependent enzymes and induces severe cobalamin deficiency in C. elegans.

Appropriate nutrient supplementation in celiac disease

Reduced levels of iron, folate, vitamin B12, vitamin D, zinc, and magnesium are common in untreated celiac disease (CD) patients probably due to loss of brush border proteins and enzymes needed for the absorption of these nutrients. In the majority of patients, removal of gluten from the diet leads to histological recovery and normalization of iron, vitamin, and mineral levels. Iron deficiency anemia is the most common extra-intestinal sign of CD and usually resolves with adherence to a gluten-free diet. However, deficiencies of both folate and vitamin B12 may persist in some patients on a gluten-free diet, thus requiring vitamin supplementation to improve subjective health status. Similarly, exclusion of gluten from the diet does not always normalize bone mineral density; in these cases, supplementation of vitamin D and calcium is recommended. Resolution of mucosal inflammation may not be sufficient to abrogate magnesium deficiency. Since gluten-free cereal products have a lower magnesium content as compared with gluten-containing counterparts, a magnesium-enriched diet should be encouraged in CD patients. In this article we discuss the frequency and clinical relevance of nutrient deficiency in CD and whether and when nutrient supplementation is needed.

Biological variability and impact of oral contraceptives on vitamins B(6), B(12) and folate status in women of reproductive age

Vitamins B₆, B₁₂ and folate play crucial metabolic roles especially during the reproductive years for women. There is limited reporting of within-subject variability of these vitamins. This study aimed to determine the within and between subject variability in serum vitamins B₆, B₁₂, folate and erythrocyte folate concentrations in young women; identify factors that contribute to variability; and determine dietary intakes and sources of these vitamins. Data were obtained from the control group of a trial aimed at investigating the effect of iron on the nutritional status of young women (age 25.2 ± 4.2 year; BMI 21.9 ± 2.2 kg/m²). The coefficients of variability within-subject (CV_I) and between-subject (CV_G) for serum vitamins B₆, B₁₂ and folate, and erythrocyte folate were calculated. Food frequency questionnaires provided dietary data. CV_I and CV_G were in the range 16.1%–25.7% and 31.7%–62.2%, respectively. Oral contraceptive pill (OCP) use was associated (P = 0.042) with lower serum vitamin B₁₂ concentrations. Initial values were 172 ± 16 pmol/L and 318 ± 51 pmol/L for OCP and non-OCP users, respectively; with differences maintained at four time points over 12 weeks. BMI, age, physical activity, alcohol intake and haematological variables did not affect serum or erythrocyte vitamin concentrations. Vitamin B₁₂ intakes were derived from traditional and unexpected sources including commercial energy drinks. Young women using OCP had significantly lower serum vitamin B₁₂ concentrations. This should be considered in clinical decision making and requires further investigation.

Diet and asthma: vitamins and methyl donors

Diet changes can partly explain the high burden of asthma in industrialised nations. Findings from experimental studies have stimulated many observational studies of the association between vitamins (A, C, D, and E) or nutrients acting as methyl donors (folate, vitamin B12, and choline) and asthma. However, observational studies are susceptible to several sources of bias; well conducted randomised controlled trials (RCTs) are the gold standard to establish whether diet has an effect on asthma. Evidence from observational studies and a few RCTs strongly justifies ongoing and future RCTs in three areas: vitamin D for the prevention or treatment of asthma, choline supplementation as adjuvant treatment for asthma, and vitamin E to prevent the detrimental effects of air pollution in patients with asthma. At present, insufficient evidence exists to recommend supplementation with any vitamin or nutrient acting as a methyl donor to prevent or treat asthma.

Discomfort symptoms reduction and ocular surface parameters recovery with Artelac Rebalance treatment in mild-moderate dry eye

PURPOSE

To evaluate Artelac Rebalance® eyedrops' efficacy in symptoms reduction, ocular surface parameters recovery, and tolerability in the treatment of mild to moderate dry eye.

METHODS

Fifteen patients were enrolled. Inclusion criteria were Ocular Surface Disease Index (OSDI) score >16, tear film break-up time (TFBUT) <10 seconds, Schirmer test I >10 mm/5 min, and mild ocular surface damage (Oxford grading) ≤3. Artelac Rebalance® eyedrops were administered 3 times daily for 2 months. Patients were evaluated at enrollment, after 2 days of washout (baseline), and after 1 and 2 months of treatment. Parameters for ocular discomfort (OSDI score), tear film quality (Schirmer test I, TFBUT, tear osmolarity), ocular surface damage (fluorescein staining, conjunctival imprint cytology), and inflammation (scraping cytology and exuded serum albumin) were measured. Tolerability and satisfaction were assessed by validated questionnaires.

RESULTS

At endpoint versus baseline, all variables showed a statistically significant improvement (paired Student t test, p<0.01 for all parameters) as follows: OSDI score (21.9 ± 10.6 vs 35.8 ± 12.2), TFBUT (6.5 ± 1.1 s vs 5.2 ± 2.3 s), Oxford grading of corneal and conjunctival damage (0.56 ± 0.50 vs 1.16 ± 0.37), tear osmolarity (294.6 ± 2.1 mOsm/L vs 303.1 ± 4.6 mOsm/L), conjunctival goblet cell density/mm2 (140.8 ± 43.3 cells/mm2 vs 115.1 ± 15.8 cells/mm2), scraping cytology score (2.9 ± 1.0 vs 4.2 ± 1.3), and percentage of serum albumin in tears (9.2% ± 4.8% vs 24.1% ± 10.8%). Tolerability and satisfaction were scored high, with no adverse events reported.

CONCLUSIONS

Application of Artelac Rebalance® eyedrops for 2 months in mild to moderate dry eye resulted in a reduction of ocular inflammation parameters, ocular surface damage, and subjective discomfort symptoms, with a parallel improvement in tear film quality (measured by TFBUT and osmolarity).

Hypercobalaminemia induced by an energy drink after total gastrectomy: a case report

We encountered a case of hypercobalaminemia induced by oral intake of an energy drink after total gastrectomy. The patient was referred to our hospital due to findings suspicious for gastric cancer on screening. A 20 mm type 0-IIc lesion was detected in the gastric subcardia on esophagogastroduodenoscopy. Total gastrectomy followed by Roux-en-Y reconstruction was performed. He was discharged without complications. His basal serum vitamin B₁₂ level was initially maintained with monthly intramuscular injections of vitamin B₁₂. After 9 months, his serum vitamin B₁₂ level suddenly increased up to 36-fold higher than the normal range and persisted there for one year without vitamin B₁₂ injections. The patient ultimately reported consuming half a bottle of an energy drink each day during this time period. This case demonstrates the risk of unexpected hypervitaminemia resulting from self-administration of nutritional supplements.

Vitamin B12 absorption: mammalian physiology and acquired and inherited disorders

BACKGROUND

Vitamin B12 (cobalamin) is a cobalt-containing compound synthesized by bacteria and an essential nutrient in mammals, which take it up from diet. The absorption and distribution of dietary vitamin B12 to the organism is a complex process involving several gene products including carrier proteins, plasma membrane receptors and transporters. Disturbed cellular entry, transit or egress of vitamin B12 may lead to low vitamin B12 status or deficiency and eventually hematological and neurological disorders.

OBJECTIVE

The aim of this review is to summarize the causes leading to vitamin B12 deficiency including decreased intake, impaired absorption and increased requirements. Under physiological conditions, vitamin B12 bound to the gastric intrinsic factor is internalized in the ileum by a highly specific receptor complex composed by Cubilin (Cubn) and Amnionless (Amn). Following exit of vitamin B12 from the ileum, general cellular uptake from the circulation requires the transcobalamin receptor CD320 whereas kidney reabsorption of cobalamin depends on Megalin (Lrp2). Whereas malabsorption of vitamin B12 is most commonly seen in the elderly, selective pediatric, nondietary-induced B12 deficiency is generally due to inherited disorders including the Imerslund-Gräsbeck syndrome and the much rarer intrinsic factor deficiency. Biochemical, clinical and genetic research on these disorders considerably improved our knowledge of vitamin B12 absorption. This review describes basic and recent findings on the intestinal handling of vitamin B12 and its importance in health and disease.

Vitamin B₁₂ status, cognitive decline and dementia: a systematic review of prospective cohort studies

Poor vitamin B₁₂ status may lead to the development of cognitive decline and dementia but there is a large variation in the quality, design of and results reported from these investigations. We have undertaken a systematic review of the evidence for the association between vitamin B₁₂ status and cognitive decline in older adults. A database search of the literature to 2011 was undertaken, using keywords related to vitamin B₁₂ and cognition. All prospective cohort studies assessing the association of serum vitamin B₁₂ or biomarkers were included. Quality assessment and extraction of the data were undertaken by two researchers. The quality assessment tool assigns a positive, neutral or negative rating. Of 3772 published articles, thirty-five cohort studies (n 14 325 subjects) were identified and evaluated. No association between serum vitamin B₁₂ concentrations and cognitive decline or dementia was found. However, four studies that used newer biomarkers of vitamin B₁₂ status (methylmalonic acid and holotranscobalamin (holoTC)) showed associations between poor vitamin B₁₂ status and the increased risk of cognitive decline or dementia diagnosis. In general, the studies were of reasonable quality (twenty-one positive, ten neutral and four negative quality) but of short duration and inadequate subject numbers to determine whether an effect exists. Future studies should be of adequate duration (at least 6 years), recruit subjects from the seventh decade, choose markers of vitamin B₁₂ status with adequate specificity such as holoTC and/or methylmalonic acid and employ standardised neurocognitive assessment tools and not screening tests in order to ascertain any relationship between vitamin B₁₂ status and cognitive decline.

Co-occurrence of anemia, marginal vitamin B6, and folate status and depressive symptoms in older adults

Although nutrient deficiencies are thought to play roles in the development of depression, observational studies have yielded inconsistent results. This study aimed to investigate whether multiple marginal nutrient deficiencies are associated with symptoms of depression in community-dwelling older Taiwanese. Data from 1371 elderly adults recruited from the Elderly Nutrition and Health Survey in Taiwan was used in this study. Depressive symptom scores on depressed mood and emotions affecting daily life were derived from the Medical Outcomes Study Short Form-36 (SF-36). Hemoglobin, serum ferritin, plasma vitamins B(6), B(12), and folate concentration, and erythrocyte transketolase and glutathione reductase activation coefficients were measured. After adjusting for age, gender, cognitive function, physical activity, disease history, and medication in the multivariate analysis, anemia, and marginal B(6) deficiency were significantly associated with the presence of depression symptoms, respectively. In addition, co-occurrence of vitamin B(6) with low folate level and co-occurrence of anemia either with low vitamin B(6) or with folate level were all associated with the depressive mood and with depressive emotions defined by SF-36 (odds ratios [OR] in the range of 2.32-7.13, all P values ≤.05). The magnitude of the ORs is larger when the number of deficiencies increased. Elderly people with coexisting marginal deficiencies of nutrients involved in the S-adenosylmethionine and hemoglobin production were more likely to experience depressed mood and emotion that affect daily activity. Examining status of these nutrients is worthy of consideration for older adults with depressed symptoms.

The mechanisms of Mg2+ and Co2+ transport by the CorA family of divalent cation transporters

The metal ions Mg(2+) and Co(2+) are essential for life, although to different degree. They have similar chemical and physical properties, but their slight differences result in Mg(2+) to be the most abundant metal ion in living cells and the trace element Co(2+) being toxic at relatively low concentrations. Specialized transporters have evolved in living cells to supply and balance the Mg(2+) and Co(2+) need of the cells. The current knowledge of the molecular mechanisms of Mg(2+) and Co(2+) -specific transporters is very limited at this point. Recently, there has been remarkable advances to understand the CorA family, a family of transporters that are able to transport both ions. These new data have increased our insights in how Mg(2+) and Co(2+) are translocated across membranes. Presently, CorA is probably the best system to study the mechanisms of Mg(2+) and Co(2+) transport. This chapter discusses the mechanisms through which CorA selects, transports, and regulates the translocation of its substrate. In addition, we highlight the physical and chemical properties of the substrates, which are important parameters required for better understanding of the transporter action.

B vitamin status, dietary intake and length of stay in a sample of elderly rehabilitation patients

OBJECTIVES

To investigate the relationships between previous diet, biomarkers of selected B vitamins, nutritional status and length of stay.

DESIGN

Cross sectional study.

SETTING

Geriatric rehabilitation patients, Sydney, Australia.

PARTICIPANTS

Fifty two consenting patients with normal serum creatinine levels and no dementia.

MEASUREMENTS

Serum vitamin B12, plasma vitamin B6, serum and erythrocyte folate, homocysteine and methylmalonic acid (MMA) concentrations; dietary intake using a validated semi-quantitative food frequency questionnaire and nutritional assessment using the Mini Nutritional Assessment (MNA). Length of stay data were collected from medical records after discharge.

RESULTS

The age was 80 ± 8 year (mean ± SD), BMI 26.4 ± 6.8 kg/m2 and MNA score 22 ± 3 indicating some risk of malnutrition. Deficiencies of vitamins B6, B12 and folate were found in 30, 22 and 5 subjects respectively. Length of stay was positively correlated with age and MMA (Spearman's correlation 0.4, p<0.01 and 0.28, p<0.05 respectively) and negatively correlated with albumin, vitamin B6 and MNA score (Spearman's correlation -0.35, -0.33 and -0.29, p<0.05). After adjustment for age and sex, ln vitamin B6 and ln MMA concentrations were significant in predicting ln LOS (p=0.006 and p=0.014 respectively).

CONCLUSION

The study indicates a high risk of vitamin B deficiencies in the elderly and suggests that deficiencies of vitamins B6 and B12 are associated with length of stay. This is concerning as B vitamin status is rarely fully assessed.