Sensitivity of serum methylmalonic acid and total homocysteine determinations for diagnosing cobalamin and folate deficiencies

Mandatory fortification of the food supply with cobalamin: an idea whose time has not yet come

The success of folic acid fortification has generated consideration of similar fortification with cobalamin for its own sake but more so to mitigate possible neurologic risks from increased folate intake by cobalamin-deficient persons. However, the folate model itself, the success of which was predicted by successful clinical trials and the known favorable facts of high folic acid bioavailability and the infrequency of folate malabsorption, may not apply to cobalamin fortification. Cobalamin bioavailability is more restricted than folic acid and is unfortunately poorest in persons deficient in cobalamin. Moreover, clinical trials to demonstrate actual health benefits of relevant oral doses have not yet been done in persons with mild subclinical deficiency, who are the only practical targets of cobalamin fortification because >94% of persons with clinically overt cobalamin deficiency have severe malabsorption and therefore cannot respond to normal fortification doses. However, it is only in the severely malabsorptive disorders, such as pernicious anemia, not subclinical deficiency, that neurologic deterioration following folic acid therapy has been described to date. It is still unknown whether mild deficiency states, which usually arise from normal absorption or only food-bound cobalamin malabsorption, have real health consequences or how often they progress to overt clinical cobalamin deficiency. Reports of cognitive or other risks in the common subclinical deficiency state, although worrisome, have been inconsistent. Moreover, their observational nature proved neither causative connections nor documented health benefits. Extensive work, especially randomized clinical trials, must be done before mandatory dietary intervention on a national scale can be justified.

Hyperhomocysteinemia, methylenetetrahydrofolate reductase c.677C>T polymorphism and risk of cancer: cross-sectional and prospective studies and meta-analyses of 75,000 cases and 93,000 controls

Global DNA hypomethylation associates with development of cancer. DNA hypomethylation also associates with hyperhomocysteinemia and MTHFR c.677C>T homozygosity, both of which may associate with increased risk of cancer. We tested the putative association of hyperhomocysteinemia with cancer and the association of the MTHFR c.677TC>T variant with hyperhomocysteinemia and with cancer. We performed a cross-sectional study of 5,949 Danish general population adults, a prospective study of 9,235 Danish general population adults with up to 60 years of registry surveillance, and meta-analyses of 231 studies including 74,671 cases and 93,344 controls. Cross-sectionally, plasma homocysteine levels were 12.9 and 11.6 μmol/L in those with and without cancer (p < 0.0001). However, homocysteine levels increased with age and age-adjusted odds ratio for any cancer in those with homocysteine levels >12.4 versus < 9.4 μmol/L did not differ from 1.0. In cancer-free participants, plasma homocysteine levels were 14.7 and 11.7 μmol/L in MTHFR c.677C>T homozygtes and noncarriers (p < 0.0001). Prospectively, hazard ratios for any cancer and for cancer subtypes in MTHFR c.677C>T homozygotes versus noncarriers did not differ from 1.0. However, in meta-analyses odds ratio for MTHFR c.677C>T homozygotes versus noncarriers were 1.07 (95% CI: 1.01-1.12) for any cancer, 1.77 (1.17-2.68) for esophagus cancer, 1.40 (1.19-1.66) for gastric cancer and 0.85 (0.77-0.94) for colorectal cancer. Increased plasma homocysteine levels are not associated with an increased age-adjusted risk of any cancer. However, MTHFR c.677C>T homozygosity with lifelong hyperhomocysteinemia and hence hypomethylation associate with increased risk of esophagus and gastric cancer, and with decreased risk of colorectal cancer.

Oral vitamin B12 for patients suspected of subtle cobalamin deficiency: a multicentre pragmatic randomised controlled trial

Background

Evidence regarding the effectiveness of oral vitamin B12 in patients with serum vitamin B12 levels between 125-200 pM/l is lacking. We compared the effectiveness of one-month oral vitamin B12 supplementation in patients with a subtle vitamin B12 deficiency to that of a placebo.

Methods

This multicentre (13 general practices, two nursing homes, and one primary care center in western Switzerland), parallel, randomised, controlled, closed-label, observer-blind trial included 50 patients with serum vitamin B12 levels between 125-200 pM/l who were randomized to receive either oral vitamin B12 (1000 μg daily, N = 26) or placebo (N = 24) for four weeks. The institution's pharmacist used simple randomisation to generate a table and allocate treatments. The primary outcome was the change in serum methylmalonic acid (MMA) levels after one month of treatment. Secondary outcomes were changes in total homocysteine and serum vitamin B12 levels. Blood samples were centralised for analysis and adherence to treatment was verified by an electronic device (MEMS; Aardex Europe, Switzerland). Trial registration: ISRCTN 22063938.

Results

Baseline characteristics and adherence to treatment were similar in both groups. After one month, one patient in the placebo group was lost to follow-up. Data were evaluated by intention-to-treat analysis. One month of vitamin B12 treatment (N = 26) lowered serum MMA levels by 0.13 μmol/l (95%CI 0.06-0.19) more than the change observed in the placebo group (N = 23). The number of patients needed to treat to detect a metabolic response in MMA after one month was 2.6 (95% CI 1.7-6.4). A significant change was observed for the B12 serum level, but not for the homocysteine level, hematocrit, or mean corpuscular volume. After three months without active treatment (at four months), significant differences in MMA levels were no longer detected.

Conclusions

Oral vitamin B12 treatment normalised the metabolic markers of vitamin B12 deficiency. However, a one-month daily treatment with1000 μg oral vitamin B12 was not sufficient to normalise the deficiency markers for four months, and treatment had no effect on haematological signs of B12 deficiency.

A randomized placebo controlled trial of homocysteine lowering to reduce cognitive decline in older demented people

INTRODUCTION

Whether homocysteine lowering by B vitamins can reduce cognitive decline in Alzheimer disease and vascular dementia patients is unclear.

METHODS AND MATERIALS

140 subjects with mild to moderate Alzheimer disease or vascular dementia were randomly assigned to take 1 mg of methylcobalamin and 5 mg of folic acid, or placebo once daily for 24 months. The primary outcome was Mattis dementia rating scale (MDRS). Secondary outcomes were MDRS domain scores, neuropsychiatric inventory and Cornell scale for depression in dementia. Measurements were performed at baseline and every six months during the study. Fasting plasma tHCY concentrations were measured at baseline and month 18.

RESULTS

Trial groups were well matched in baseline characteristics. The average plasma tHCY concentration of subjects was 14.1 ± 3.8 μmol/L. 80% of subjects completed the trial. The supplement group had average plasma tHCY reduced to 9.3 ± 2.7 μmol/L. There was no significant group difference in changes in any of the neuropsychological scores, but among those with elevated plasma tHCY (>13 μmol/L), the decline in MDRS (construction domain) was significantly smaller in the supplement group (median 0 versus 2 points in placebo group, P = 0.003).

CONCLUSION

Homocysteine lowering in dementia patients did not significantly reduce global cognitive decline.

Acute presentation of dizziness in vitamin B12 deficient old patient of cardiac disease: a case report

BACKGROUND

Neuropsychiatric and hematological manifestations of vitamin B12 deficiency are well known. The present report highlights the biochemical basis for the impaired synthesis of DNA and neurological disorders associated with vitamin B12 deficiency.

METHODS

We present a case of an old patient who developed acute ataxia, dizziness and imbalance 2 days after pacemaker implantation in a cardiac care unit.

RESULTS

On evaluation, the patient was found to have low vitamin B12 levels (121 pmol/l) with raised plasma homocysteine levels (28 μmol/l) and methylmalonic acid levels (17 μmol/l). Neurological examination revealed signs and symptoms of peripheral neuropathy. CT scan of the brain was found to be normal. The usual hematological presentation was absent in this case. The patient responded dramatically to parenteral vitamin B12 supplementation.

CONCLUSION

Though frequent, the vitamin B12 deficiency often goes unnoticed in elderly population. So, with this report we emphasize that deficiency of serum vitamin B12 levels should be suspected and evaluated in elderly patients presenting with neuropsychiatric symptoms.

Human papilloma virus persistence and neopterin, folate and homocysteine levels in cervical dysplasias

OBJECTIVE

To investigate the relationship between human papilloma virus (HPV) infection persistence and serum folate, vitamin B12, homocysteine, neopterin levels in cervical dysplasia.

STUDY DESIGN

Through the years 2007-2008, 122 women who have admitted to Gynecology Clinic were evaluated for cervical cytology, demographical characteristics, HPV infection, serum folate, vitamin B12, homocysteine, albumin, and neopterin levels.

RESULTS

Considering all the cases, the highest percentage of the HPV-infected patients was in high-grade squamous intraepithelial lesion (HSIL) group (83%, n = 25). The serum folate levels in all patient groups [HSIL 10.0 ± 0.4 ng/ml, low-grade squamous intraepithelial lesion (LSIL) 10.6 ± 0.5 ng/ml, atypical squamous cells-undetermined significance (ASCUS) 11.1 ± 0.8 ng/ml] were lower than control group (11.9 ± 0.5 ng/ml; p < 0.05). The vitamin B12 levels were not significantly altered in any of the patient groups. The serum homocysteine levels in all patient groups (HSIL 10.4 ± 0.5 Umol/l, LSIL 10.1 ± 0.5 Umol/l, ASCUS 10.5 ± 0.7 Umol/l) were higher than the control group (7.9 ± 0.5 Umol/l; p < 0.05). The neopterin levels of HSIL group (1.0 ± 0.2 ng/ml) were lower than the control group (1.5 ± 0.2 ng/ml; p < 0.05). The serum neopterin concentrations of HSIL with HPV group (0.6 ± 0.1 ng/ml) were significantly lower than HSIL without HPV (2.4 ± 0.9 ng/ml) and other study groups (p < 0.05). The serum homocysteine levels of HSIL HPV(+) group and LSIL HPV(+) were higher than control group (p < 0.05). The serum albumin levels of HSIL with HPV group are lower than control and other groups (p < 0.05). In all cervical dysplasia groups, folate levels in patients infected with HPV are lower than in HPV(-) patients (p < 0.05).

CONCLUSIONS

Folic acid deficiency could be caused by insufficient cellular immunity. In case of folate deficiency, the predisposition of HPV infection persistency and progression of cervical dysplasia increase. The fact that neopterin is a strong cellular immunity marker and it was detected in patients with HPV persistence and cervical dysplasia in lower levels shows that these patients may have relatively insufficient immune system. In order for dysplasia progression to be prevented, folate fortification on diets may be advised to HPV-infected women.

Serum vitamin B12 and homocysteine levels in pregnant women with neural tube defect

OBJECTIVE

The aim of the study is to investigate the importance of serum vitamin B12 levels in pregnant women with foetal neural tube defect (NTD).

STUDY DESIGN

This study consists of 31 pregnant women having fetuses with NTD. The pregnant women in the study group were selected among cases with normal folate levels. Serum vitamin B12 levels were investigated. Additionally, complete blood count, serum iron level, iron binding capacity, ferritin, folate, free T(3), free T(4), thyroid stimulating hormone and plasma homocysteine levels were measured. Control group consisted of 32 pregnant women who did not have a history of NTD in previous pregnancies and did not have fetuses with NTD in present pregnancy. NTD was diagnosed between 14th and 20th gestational age. The mean gestational age of members of control group was the same as those of NTD group.

RESULTS

There was no statistically significant difference between pregnants with NTD and control group according to number of cases with vitamin B12 deficiency.

CONCLUSION

It seems that vitamin B12 deficiency does not play a causative role in the development of foetal NTD. Monitoring maternal homocystein levels might be important in understanding the aetiologies of foetal NTD.

S phase entry causes homocysteine-induced death while ataxia telangiectasia and Rad3 related protein functions anti-apoptotically to protect neurons

A major phenotype seen in neurodegenerative disorders is the selective loss of neurons due to apoptotic death and evidence suggests that inappropriate re-activation of cell cycle proteins in post-mitotic neurons may be responsible. To investigate whether reactivation of the G1 cell cycle proteins and S phase entry was linked with apoptosis, we examined homocysteine-induced neuronal cell death in a rat cortical neuron tissue culture system. Hyperhomocysteinaemia is a physiological risk factor for a variety of neurodegenerative diseases, including Alzheimer's disease. We found that in response to homocysteine treatment, cyclin D1, and cyclin-dependent kinases 4 and 2 translocated to the nucleus, and p27 levels decreased. Both cyclin-dependent kinases 4 and 2 regained catalytic activity, the G1 gatekeeper retinoblastoma protein was phosphorylated and DNA synthesis was detected, suggesting transit into S phase. Double-labelling immunofluorescence showed a 95% co-localization of anti-bromodeoxyuridine labelling with apoptotic markers, demonstrating that those cells that entered S phase eventually died. Neurons could be protected from homocysteine-induced death by methods that inhibited G1 phase progression, including down-regulation of cyclin D1 expression, inhibition of cyclin-dependent kinases 4 or 2 activity by small molecule inhibitors, or use of the c-Abl kinase inhibitor, Gleevec, which blocked cyclin D and cyclin-dependent kinase 4 nuclear translocation. However, blocking cell cycle progression post G1, using DNA replication inhibitors, did not prevent apoptosis, suggesting that death was not preventable post the G1-S phase checkpoint. While homocysteine treatment caused DNA damage and activated the DNA damage response, its mechanism of action was distinct from that of more traditional DNA damaging agents, such as camptothecin, as it was p53-independent. Likewise, inhibition of the DNA damage sensors, ataxia-telangiectasia mutant and ataxia telangiectasia and Rad3 related proteins, did not rescue apoptosis and in fact exacerbated death, suggesting that the DNA damage response might normally function neuroprotectively to block S phase-dependent apoptosis induction. As cell cycle events appear to be maintained in vivo in affected neurons for weeks to years before apoptosis is observed, activation of the DNA damage response might be able to hold cell cycle-induced death in check.

Subnormal vitamin B12 concentrations and anaemia in older people: a systematic review

BACKGROUND

Pernicious anaemia is undeniably associated with vitamin B12 deficiency, but the association between subnormal vitamin B12 concentrations and anaemia in older people is unclear. The aim of this systematic review was to evaluate the association between subnormal vitamin B12 concentrations and anaemia in older people.

METHODS

Clinical queries for aetiology and treatment in bibliographic databases (PubMed [01/1949-10/2009]; EMBASE [01/1980-10/2009]) were used. Reference lists were checked for additional relevant studies. Observational studies (> or =50 participants) and randomized placebo-controlled intervention trials (RCTs) were considered.

RESULTS

25 studies met the inclusion criteria. Twenty-one observational cross-sectional studies (total number of participants n = 16185) showed inconsistent results. In one longitudinal observational study, low vitamin B12 concentrations were not associated with an increased risk of anaemia (total n = 423). The 3 RCTs (total n = 210) were well-designed and showed no effect of vitamin B12 supplementation on haemoglobin concentrations during follow-up in subjects with subnormal vitamin B12 concentrations at the start of the study. Due to large clinical and methodological heterogeneity, statistical pooling of data was not performed.

CONCLUSIONS

Evidence of a positive association between a subnormal serum vitamin B12 concentration and anaemia in older people is limited and inconclusive. Further well-designed studies are needed to determine whether subnormal vitamin B12 is a risk factor for anaemia in older people.

Functional vitamin B12 deficiency in alcoholics: an intriguing finding in a retrospective study of megaloblastic anemic patients

BACKGROUND

Measurement of serum cobalamin levels is the standard investigation for assessing Vitamin B12 deficiency. However some patients with clinical evidence of cobalamin deficiency may have serum levels within the normal range. Since falsely increased values of cobalamin can be caused by alcoholic liver disease, we evaluated the impact of this disease on the diagnosis of cobalamin and folic acid deficiency.

METHODS

We reviewed data of 101 adult patients with megaloblastic anemia assessed by measuring in parallel serum cobalamin, serum folate and red blood cell folate levels. Further tests were performed in order to find the cause of megaloblastosis. All patients were treated with cobalamin and/or folic acid therapy.

RESULTS

Vitamin B12, folate and both deficiency were found in 86, 5 and 6 cases respectively. Normal cobalamin serum levels, normal serum and erythrocyte folate levels were found only in 3 patients, all alcohol-dependent, while in another alcoholic borderline vitamin B12 serum levels were found. All the four patients responded to cobalamin treatment.

CONCLUSION

Some alcohol-dependent patients with megaloblastic anemia may respond to vitamin B12 treatment despite normal cobalamin serum levels; therefore in alcoholics caution is urged in the interpretation of these vitamin assays, because of possible functional vitamin B12 deficiency.

Fluorescent and colorimetric probes for detection of thiols

Due to the biological importances of thiols, such as cysteine, homocysteine and glutathione, the development of optical probes for thiols has been an active research area in recent few years. This critical review focuses on the fluorescent or colorimetric sensors for thiols according to their unique mechanisms between sensors and thiols, including Michael addition, cyclization with aldehyde, cleavage of sulfonamide and sulfonate ester by thiols, cleavage of selenium-nitrogen bond by thiols, cleavage of disulfide by thiols, metal complexes-oxidation-reduction, metal complexes-displace coordination, nano-particles and others (110 references).

Analytical recovery of folate and its degradation products in human serum stored at -25 degrees C for up to 29 years

Epidemiological studies on folate and chronic diseases often involve the use of frozen serum stored in biorepositories for decades. Folate instability may attenuate associations between folate status and study endpoints. In this cross-sectional study, we retrieved serum samples stored at -25 degrees C for 0, 4, 6, 17, or 29 y in the Janus biobank. Samples were obtained from a total of 650 men aged 40-49 y at the time of blood collection and were evenly distributed according to storage time. Folate was determined by a liquid chromatography tandem MS (LC-MS/MS) assay that measures 5-methyltetrahydrofolate (5mTHF), its oxidation product 4-alpha-hydroxy-5-methyltetrahydrofolate (hmTHF), and other folate species; by a Lactobacillus rhamnosus microbiological assay; and by LC-MS/MS as p-aminobenzoylglutamate (pABG) equivalents after oxidation and mild acid hydrolysis of the folate species. Concentrations of 5mTHF and microbiologically active folate were lower in samples that had been subjected to long-term storage and the data were consistent with a decrease of 3.2 and 2.8%/y, respectively. hmTHF was detected in all specimens but did not accumulate upon long-term storage (>4 y). Folate measured as pABG declined at a slow rate of 0.98%/y and approximately 80% of the folate was recovered after 29 y of storage. B-vitamin status did not differ between individuals delivering samples at different time points, as assessed by measuring total homocysteine, methylmalonic acid, and serum vitamin B-12. In conclusion, folate is substantially degraded in serum frozen for decades but can to a large extent be recovered as pABG equivalents. The pABG assay appears to be the method of choice for the determination of folate status in archival serum samples.

Neurologic presentations of nutritional deficiencies

Optimal functioning of the central and peripheral nervous system is dependent on a constant supply of appropriate nutrients. The first section of this review discusses neurologic manifestations related to deficiency of key nutrients such as vitamin B(12), folate, copper, vitamin E, thiamine, and others. The second section addresses neurologic complications related to bariatric surgery. The third sections includes neurologic presentations caused by nutrient deficiencies in the setting of alcoholism. The concluding section addresses neurologic deficiency diseases that have a geographic predilection.

Subclinical vitamin B12 deficiency in pregnant women attending an antenatal clinic in Nigeria

SUMMARY

Inadequate vitamin B12 status in a pregnant woman increases the risk for adverse maternal and fetal outcomes. The use of serum vitamin B12 concentration alone to assess vitamin B12 status in pregnant women is unreliable because of the decrease in serum vitamin B12 levels in normal pregnancy. The combination of serum vitamin B12 and methylmalonic acid (MMA) concentrations may provide a better estimate of vitamin B12 status. We obtained blood samples from 98 pregnant women in the third trimester at an antenatal clinic in Jos, Nigeria. All subjects were taking iron and folate supplements. Twelve of the subjects had a serum vitamin B12 concentration <148 pmol/l and 18 subjects had a serum MMA level >271 nmol/l. Using a combination of low serum vitamin B12 and elevated MMA concentrations, eight subjects were classified as having subclinical vitamin B12 deficiency. Because of the potential harmful consequences of vitamin B12 deficiency in pregnant women, it would be advisable to add vitamin B12 supplements to the existing regimen of folate and iron supplements currently provided to pregnant women in Nigeria.

Advances in the understanding of cobalamin assimilation and metabolism

The haematological and neurological consequences of cobalamin deficiency define the essential role of this vitamin in key metabolic reactions. The identification of cubilin-amnionless as the receptors for intestinal absorption of intrinsic factor-bound cobalamin and the plasma membrane receptor for cellular uptake of transcobalamin bound cobalamin have provided a clearer understanding of the absorption and cellular uptake of this vitamin. As the genes involved in the intracellular processing of cobalamins and genetic defects of these pathways are identified, the metabolic disposition of cobalamins and the proteins involved are being recognized. The synthesis of methylcobalamin and 5'-deoxyadenosylcobalamin, their utilization in conjunction with methionine synthase and methylmalonylCoA mutase, respectively, and the metabolic consequences of defects in these pathways could provide insights into the clinical presentation of cobalamin deficiency.

Hypersegmented neutrophils and reversible hyperpigmentation in vitamin B(12) deficiency in Ghana

The present report concerns three cases of vitamin B(12) deficiency in Ghana. One case presented in the expected textbook manner with neurological signs, anaemia and a low serum vitamin B(12) level, whereas another presented with anaemia and hyperpigmentation, but a high serum vitamin B(12) level. Both responded well to treatment with vitamin B(12). It is suggested from the literature that the high serum vitamin B(12) may have been the result of high intrinsic factor antibodies. The third patient presented with haemolytic anaemia with depression, and was managed as such initially. She responded well, with a normalisation of haemoglobin levels. Persisting vague neurological symptoms lead to a check of serum vitamin B(12), which was found to be low. Her symptoms cleared with vitamin B(12) treatment. The need for a pragmatic approach in diagnosing vitamin B(12) deficiency is stressed.

Health technology assessment in clinical biochemistry. Methylmalonic acid: a Danish showcase

In 1992 plasma methylmalonic acid (MMA) was introduced in Denmark for diagnosing vitamin B-12 deficiency. Now, 10 years later, we report on a health technology assessment (HTA) suggesting that the clinical usefulness of MMA is uncertain. MMA is an obvious component for measurement in the diagnosis of vitamin B-12 deficiency because MMA accumulates when there is a lack of vitamin B-12, and technologically the analysis is of high quality. The diagnostic sensitivity of MMA is high, whereas the diagnostic specificity is debatable, and our results suggest it to be relatively low. The organizational aspect implies that both MMA and P-cobalamins have been increasingly employed, though no consensus on the use of the analyses has emerged. The benefit to the patient is not obvious. An increased level of MMA does not predict further increases over time, and vitamin B-12 treatment shows limited clinical benefit in individuals with a moderately increased MMA. The economic consequences of introducing MMA were an increase in the costs of MMA and P-cobalamins of 12% per year during 1992-2000 and an increase in the turnover of vitamin B-12 preparations of 9% per year. In conclusion, MMA was introduced on sound grounds for both pathophysiological considerations and analytical quality. Our HTA shows that the resources employed to diagnose and to treat vitamin B-12 deficiency have increased considerably, but yet we have no evidence to suggest the clinical benefit.

Routine determination of serum methylmalonic acid and plasma total homocysteine in Norway

OBJECTIVE

To study the total number of combined analyses of methylmalonic acid (MMA) and total plasma homocysteine (tHcy) carried out during February 1998 at the Central Laboratory of Haukeland University Hospital.

METHODS

Laboratory data and requester comments of 2917 subjects in whom MMA was requested during February 1998, were retrieved from the laboratory information system (LIS). In 2520 cases, the results from the combined analyses of MMA and tHcy were available. Requester comments were registered in the LIS in 1084 cases. Results from additional laboratory analyses were accessible in about 10%, of cases.

RESULTS

General practitioners requested MMA and tHcy on three main indications, i.e. low cobalamin, "control" and neurological symptoms. Metabolites were requested in twice as many women than men. Furthermore, MMA was requested in younger age groups of women compared with men. Plasma tHcy and MMA showed positive correlations with age and serum creatinine, and tHcy was generally 1-2 micromol/L higher in men than in premenopausal women. In cobalamin- (serum cobalamin > 300 pmol/L) and/or folate- (serum folate > 10 nmol/L) replete subjects, the average difference in MMA or tHcy according to the highest and lowest creatinine quartiles was 0.08 and 5-6 micromol/L, respectively. Different combinations of MMA and tHcy were evaluated by using a 5 x 5 matrix of predefined concentration intervals. Based on this matrix, cobalamin and folate deficiency could be excluded or the likely diagnoses proposed in 76% of cases. Cobalamin deficiency or folate deficiency was likely in about 7% and 12% of the subjects investigated, respectively.

CONCLUSIONS

A combined analysis of MMA and tHcy provides complementary diagnostic information. When interpreting MMA and tHcy values, age, gender and renal function in particular must be taken into account. Typical combinations of MMA and tHcy concentration intervals could be proposed, which could either exclude deficiency or indicate likely diagnoses and/or influence of confounders.

Neuropathy as a potential complication of levodopa use in Parkinson's disease

The presence and potential etiologies of peripheral neuropathy (PN) in patients with Parkinson's Disease (PD) is unknown. We examined for presence of PN in patients with PD. From a PD patient population of 500 patients screened for features of symptomatic PN, patients were further selected for clinical, electrophysiological, and laboratory studies related to PN. This PD patient population with idiopathic PN (PD-IPN) was compared to a group of PD patients without PN (PD-only), and a large group of patients without PD with idiopathic PN (IPN) for abnormalities in Cbl, fasting homocysteine (Hcy), and fasting methylmalonic acid (MMA) levels. PD-IPN and IPN patients identified with abnormalities in Cbl, Hcy, or MMA levels were treated with intramuscular Cbl for 1 to 2 years. Of 49 PD patients with symptomatic PN, 34 patients (69%) had PD-IPN, and 32/34 (94%) had abnormal Hcy or MMA levels as compared to 26/258 (10%) of IPN patients. Cumulative lifetime L-dopa dosage and fasting MMA levels were associated with PN severity. Cbl therapy led to improvements in Hcy and MMA levels in all groups, and PN in PD-IPN patients stabilized during therapy. PN in PD patients may be associated with iatrogenic Cbl metabolic abnormalities. Alternatively PN may be a peripheral nervous system manifestation of PD.

Evaluation of distal symmetric polyneuropathy: the role of laboratory and genetic testing (an evidence-based review)

Distal symmetric polyneuropathy (DSP) is the most common variety of neuropathy. Since the evaluation of this disorder is not standardized, the available literature was reviewed to provide evidence-based guidelines regarding the role of laboratory and genetic tests for the assessment of DSP. A literature review using MEDLINE, EMBASE, Science Citation Index, and Current Contents was performed to identify the best evidence regarding the evaluation of polyneuropathy published between 1980 and March 2007. Articles were classified according to a four-tiered level of evidence scheme and recommendations were based on the level of evidence. (1) Screening laboratory tests may be considered for all patients with polyneuropathy (Level C). Those tests that provide the highest yield of abnormality are blood glucose, serum B(12) with metabolites (methylmalonic acid with or without homocysteine), and serum protein immunofixation electrophoresis (Level C). If there is no definite evidence of diabetes mellitus by routine testing of blood glucose, testing for impaired glucose tolerance may be considered in distal symmetric sensory polyneuropathy (Level C). (2) Genetic testing is established as useful for the accurate diagnosis and classification of hereditary neuropathies (Level A). Genetic testing may be considered in patients with cryptogenic polyneuropathy who exhibit a hereditary neuropathy phenotype (Level C). Initial genetic testing should be guided by the clinical phenotype, inheritance pattern, and electrodiagnostic (EDX) features and should focus on the most common abnormalities, which are CMT1A duplication/HNPP deletion, Cx32 (GJB1), and MFN2 mutation screening. There is insufficient evidence to determine the usefulness of routine genetic testing in patients with cryptogenic polyneuropathy who do not exhibit a hereditary neuropathy phenotype (Level U).

Genetic polymorphisms involved in folate metabolism and concentrations of methylmalonic acid and folate on plasma homocysteine and risk of coronary artery disease

OBJECTIVES

Alterations in the enzymes involved in homocysteine (Hcy) metabolism or vitamin deficiency could play a role in coronary artery disease (CAD) development. This study investigated the influence of MTHFR and MTR gene polymorphisms, plasma folate and MMA on Hcy concentrations and CAD development. MMA and folate concentrations were also investigated according to the polymorphisms.

METHODS

Two hundred and eighty-three unrelated Caucasian individuals undergoing coronary angiography (175 with CAD and 108 non-CAD) were assessed in a case-control study. Plasma Hcy and MMA were measured by liquid chromatography/tandem mass spectrometry. Plasma folate was measured by competitive immunoassay. Dietary intake was evaluated using a nutritional questionnaire. Polymorphisms MTHFR and MTR were investigated by polymerase chain reaction (PCR) followed by enzyme digestion or allele-specific PCR.

RESULTS

Hcy mean concentrations were higher in CAD patients compared to controls, but below statistical significance (P = 0.246). Increased MMA mean concentrations were frequently observed in the CAD group (P = 0.048). Individuals with MMA concentrations >0.5 micromol/l (vitamin B(12) deficiency) were found only in the CAD group (P = 0.004). A positive correlation between MMA and Hcy mean concentrations was observed in both groups, CAD (P = 0.001) and non-CAD (P = 0.020). MMA mean concentrations were significantly higher in patients with hyperhomocysteinemia in both groups, CAD and non-CAD (P = 0.0063 and P = 0.013, respectively). Folate mean concentration was significantly lower in carriers of the wild-type MTHFR 1298AA genotype (P = 0.010).

CONCLUSION

Our results suggest a correlation between the MTHFR A1298C polymorphism and plasma folate concentration. Vitamin B(12) deficiency, reflected by increased MMA concentration, is an important risk factor for the development both of hyperhomocysteinemia and CAD.

Severe vitamin B-12 deficiency in a child mimicking thrombotic thrombocytopenic purpura

We report a case of severe vitamin B-12 deficiency in a child who had a clinical presentation of hemolysis and thrombocytopenia that suggested the diagnosis of thrombotic thrombocytopenic purpura (TTP) and was associated with decreased ADAMTS13 activity. In this report, we review vitamin B-12 deficiency in children, the relationship between ADAMTS13 activity and TTP and discuss other conditions associated with decreased ADAMTS13 activity.

Cognitive and psychiatric effects of vitamin B12 replacement in dementia with low serum B12 levels: a nursing home study

BACKGROUND

The aim of this study is to determine whether B12 replacement would ameliorate cognitive and psychiatric symptoms in elderly subjects with dementia and low serum B12 levels.

METHODS

A test group (n = 28) of nursing home residents with low serum B12 levels (<250 pg/mL) and a matched comparison group (n = 28) with normal serum B12 levels (>300 pg/mL) were evaluated by blinded raters while the test group received intramuscular (IM) B12 replacement therapy. All subjects were assessed at baseline, 8 weeks, and 16 weeks with the Dementia Rating Scale, Brief Psychiatric Rating Scale, and Geriatric Depression Scale.

RESULTS

Although B12 replacement produced significant improvement in hematologic and metabolic parameters, it yielded no significant effect on cognitive or psychiatric variables. A few subjects evidenced notable individual treatment responses; however, these were not statistically more frequent than in the normal B12 group.

CONCLUSIONS

These results suggest that B12 replacement is unlikely to benefit cognitive or psychiatric symptoms in the vast majority of elderly dementia patients with low serum B12 levels.

Practice Parameter: Evaluation of distal symmetric polyneuropathy: Role of laboratory and genetic testing (an evidence-based review)

Background: Distal symmetric polyneuropathy (DSP) is the most common variety of neuropathy. Since the evaluation of this disorder is not standardized, the available literature was reviewed to provide evidence-based guidelines regarding the role of laboratory and genetic tests for the assessment of DSP.

Methods: A literature review using MEDLINE, EMBASE, and Current Contents was performed to identify the best evidence regarding the evaluation of polyneuropathy published between 1980 and March 2007. Articles were classified according to a four-tiered level of evidence scheme and recommendations were based upon the level of evidence.

Results and Recommendations: 1) Screening laboratory tests may be considered for all patients with polyneuropathy (Level C). Those tests that provide the highest yield of abnormality are blood glucose, serum B12 with metabolites (methylmalonic acid with or without homocysteine), and serum protein immunofixation electrophoresis (Level C). If there is no definite evidence of diabetes mellitus by routine testing of blood glucose, testing for impaired glucose tolerance may be considered in distal symmetric sensory polyneuropathy (Level C). 2) Genetic testing should be conducted for the accurate diagnosis and classification of hereditary neuropathies (Level A). Genetic testing may be considered in patients with cryptogenic polyneuropathy who exhibit a hereditary neuropathy phenotype (Level C). Initial genetic testing should be guided by the clinical phenotype, inheritance pattern, and electrodiagnostic features and should focus on the most common abnormalities which are CMT1A duplication/HNPP deletion, Cx32 (GJB1), and MFN2 mutation screening. There is insufficient evidence to determine the usefulness of routine genetic testing in patients with cryptogenic polyneuropathy who do not exhibit a hereditary neuropathy phenotype (Level U).

AAN = American Academy of Neurology; AANEM = American Academy of Neuromuscular and Electrodiagnostic Medicine; AAPM&R = American Academy of Physical Medicine and Rehabilitation; CMT = Charcot-Marie-Tooth; DSP = distal symmetric polyneuropathy; EDX = electrodiagnostic; GTT = glucose tolerance testing; IFE = immunofixation electrophoresis; QSS = Quality Standards Subcommittee; SPEP = serum protein electrophoresis.

Epidemiology of anemia in older adults

Anemia is a common, multifactorial condition among older adults. The World Health Organization (WHO) definition of anemia (hemoglobin concentration <12 g/dL in women and <13 g/dL in men) is most often used in epidemiologic studies of older adults. More than 10% of community-dwelling adults age 65 years and older has WHO-defined anemia. After age 50 years, prevalence of anemia increases with advancing age and exceeds 20% in those 85 years and older. In nursing homes, anemia is present in 48% to 63% of residents. Incidence of anemia in older adults is not well characterized. Among older adults with anemia, approximately one third have evidence of iron, folate, and/or vitamin B(12) deficiency, another third have renal insufficiency and/or chronic inflammation, and the remaining third have anemia that is unexplained. Several studies demonstrate that anemia is associated with poorer survival in older adults. This review details the distribution and consequences of anemia in older adults and identifies future epidemiologic research needs.

Nutritional anemias and the elderly

Nutritional anemias are important because they are easily reversed and because their underlying causes, most often unrelated to dietary intake, require individualized assessment. Iron-deficiency anemia (IDA) usually results from iron losses accompanying chronic bleeding, including loss to intestinal parasites, or from gastric disorders or malabsorption in the elderly. Cobalamin-deficiency anemia, the only nutritional anemia with predilection for the elderly, nearly always stems from failure of intrinsic factor (IF)-related absorption. Folate-deficiency anemia, the only nutritional anemia usually caused by poor intake, has nearly disappeared in countries that fortify food with folic acid. Copper-deficiency anemia, which usually results from malabsorptive disorders or from medical or nutritional interventions that provide inadequate copper or excess zinc, is uncommon but increasingly recognized. The prevalences of nutritional anemias, which are not always distinguished from non-anemic deficiency, are uncertain. The mean corpuscular volume (MCV) provides an essential diagnostic tool leading to judicious matching of relevant biochemical changes with relevant anemia. Nutritional anemias usually feature abnormal MCV, whereas the predominant anemias in the aged, especially the anemias of chronic disease/chronic inflammation (ACD/ACI), of renal failure, and of unknown causes, are typically normocytic.

Lower red blood cell counts in middle-aged subjects with shorter peripheral blood leukocyte telomere length

Although telomere biology was revealed to play an important role in several hematopoietic disorders, its impact on the age-dependent dynamics of regular hematopoiesis is poorly understood. In vitro results suggest that particularly the erythropoietic capacity might be limited by critically short telomere length (TL). However, it remains unclear whether TL also affects erythropoiesis in healthy individuals in vivo. Therefore, we analyzed the associations between relevant hematopoietic parameters and peripheral blood leukocyte TL in the apparently healthy Asklepios study population, aged approximately 35-55 years (N > 2500). Our data indicate a clear positive, age and paternal age at birth adjusted, correlation between TL and red blood cell count, both in men (p < 0.001) and women (p = 0.011). This association was particularly significant in the older segment of the population (> 45 years old, both sexes: p = 0.003) and in younger men (p = 0.013), but not in younger women (p = 0.521). Further adjustment for known determinants in a general linear model revealed that peripheral blood leukocyte TL is most probably an independent predictor of red blood cell count (p < 0.001), suggesting that critical telomere shortening might also limit erythropoiesis in vivo. While negligible in a middle-aged population, the clinical consequences might be important in the elderly (e.g. in anemia of chronic disease). Further studies are required to confirm the impact of our results.

[Thromboembolic events, abortions and a sick infant--unusual presentation of a vitamin deficiency]

Homocysteine is a risk factor for the development of thromboembolic disorders and vascular diseases. Furthermore, complications during pregnancy have been ascribed to hyperhomocysteinemia. We report on a pregnant woman being substituted by high doses folic acid for hyperhomocysteinemia. Thereby, the underlying pernicious anemia was masked. After birth, the neonate was exclusively breastfed. At the age of 5 months, the infant had to be admitted to hospital due to severe vitamin B(12)-deficiency. Using parenteral vitamin B(12) substitution, homocystein levels of the mother normalized and the infant throve and prospered again.

Intestinal malabsorption in long-term survivors of cervical cancer treated with radiotherapy

PURPOSE

The aim of this cross-sectional study is to investigate the associations between pelvic radiotherapy (RT) and markers of intestinal absorption in cervical cancer survivors (CCSs). We compared patient data with normative data from a reference population and explored the associations between cobalamin status and clinically significant diarrhea and depression.

METHODS AND MATERIALS

Fifty-five CCSs treated with RT in 1994-1999 were included in 2005 in a follow-up questionnaire study exploring physical and psychological symptoms. Blood tests, including serum (S)-vitamin B(12,) S-methylmalonic acid, S-folate, erythrocyte-folate, and plasma homocysteine, were analyzed. Differences in median values between CCSs and reference populations were evaluated by using Wilcoxon tests. Associations between variables were examined by means of multiple regression analyses.

RESULTS

Median S-vitamin B(12) level was significantly lower and median S-methylmalonic acid level was significantly higher in CCSs compared with the reference population (p < 0.001). Correction for renal function verified a likely cobalamin deficiency in 20% of CCSs (11 of 55). Diarrhea or depression was not significantly related to any of the mentioned markers of cobalamin or folate status. Fifteen percent of CCSs (8 of 55) had subnormal S-calcium values.

CONCLUSIONS

Significant cobalamin deficiency was observed in 11 (20%) and low calcium level was observed in 8 CCSs (15%) 6-12 years after pelvic RT. Neither diarrhea nor depression was associated with this deficiency. Routine monitoring of S-vitamin B(12) level is recommended, and regular intake of cobalamin should be considered in CCSs treated with RT.

How I treat cobalamin (vitamin B12) deficiency

The challenges in medical management of cobalamin deficiency lie in attention to the unique pathophysiology that underlies cobalamin deficiency, more than in the mechanics of therapy. The central physiologic principles are that clinically important deficiency is more likely to occur (and progress) when intrinsic factor-driven absorption fails than when diet is poor and that most causes take years to produce clinically obvious deficiency. Transient defects have little clinical impact. The key management principle is the importance of follow-up, which also requires knowing how the deficiency arose. The virtues of these principles are not always fully appreciated. Recent developments have made diagnosis and management more difficult by diminishing the ability to determine cobalamin absorption status. Clinicians must also grapple with premature medicalization of isolated, mild biochemical changes that added many asymptomatic cases of still undetermined medical relevance to their caseload, often expanded by inflated cobalamin level criteria. The potential for misattribution of cobalamin-unrelated presentations to nongermane cobalamin and metabolite abnormalities has grown. Pathophysiologically based management requires systematic attention to each of its individual components: correctly diagnosing cobalamin deficiency, reversing it, defining its underlying cause, preventing relapse, managing the underlying disorder and its complications, and educating the patient.

Common metabolic profile in infants indicating impaired cobalamin status responds to cobalamin supplementation

OBJECTIVE

A metabolic profile consistent with impaired cobalamin status is prevalent in breastfed infants. We investigated whether this profile reflects immature organ systems or impaired cobalamin status.

METHODS

In a single-center, randomized, placebo-controlled trial, we studied 107 six-week-old infants. The infants were randomly assigned to receive either an intramuscular injection of 400 mug of cobalamin or no intervention. Concentrations of cobalamin and folate in serum and total homocysteine, methylmalonic acid, and cystathionine in plasma were determined at enrollment and at the age of 4 months.

RESULTS

There were no significant differences between the intervention group (n = 54) and the control group (n = 53) in the concentrations of any vitamin marker at baseline (6 weeks). At 4 months, the supplement-treated infants had a 75% higher median serum cobalamin level and remarkable reductions in median plasma total homocysteine (from 7.46 to 4.57 micromol/L) and methylmalonic acid (from 0.58 to 0.20 micromol/L) levels, whereas levels of both metabolites were essentially unchanged during the follow-up period in the control group.

CONCLUSIONS

Cobalamin supplementation changed all markers of impaired cobalamin status (low cobalamin, high total homocysteine, and high methylmalonic acid levels) toward a profile observed in cobalamin-replete older children and adults. Therefore, the high total homocysteine and methylmalonic acid levels reported for a large fraction of infants reflect not immature metabolism but rather insufficient cobalamin levels to fully sustain cobalamin-dependent reactions fully.

The Worldwide Challenge of the Dementias: A Role for B Vitamins and Homocysteine?

Dementia has reached epidemic proportions, with an estimated 4.6 million new cases worldwide each year. With an aging world population, the prevalence of dementia will increase dramatically in the next few decades. Of the predicted 114 million who will have dementia in 2050, about three-quarters will live in less developed regions. Although strongly age-related, dementia is not an inevitable part of aging but is a true disease, caused by exposure to several genetic and nongenetic risk factors. Prevention will be possible when the nongenetic risk factors have been identified. Apart from age, more than 20 nongenetic risk factors have been postulated, but very few have been established by randomized intervention studies. Elevated blood concentrations of total homocysteine and low-normal concentrations of B vitamins (folate, vitamin B12, and vitamin B6) are candidate risk factors for both Alzheimer's disease and vascular dementia. Seventy-seven cross-sectional studies on more than 34,000 subjects and 33 prospective studies on more than 12,000 subjects have shown associations between cognitive deficit or dementia and homocysteine and/or B vitamins. Biologically plausible mechanisms have been proposed to account for these associations, including atrophy of the cerebral cortex, but a definite causal pathway has yet to be shown. Raised plasma total homocysteine is a strong prognostic marker of future cognitive decline, and is common in world populations. Low-normal concentrations of the B vitamins, the main determinant of homocysteine concentrations, are also common and occur in particularly vulnerable sections of the population, such as infants and elderly. Large-scale randomized trials of homocysteine-lowering vitamins are needed to see if a proportion of dementia in the world can be prevented.

Vitamin B12 deficiency in hypersecretors during long-term acid suppression with proton pump inhibitors

BACKGROUND

Proton pump inhibitors (PPIs) may cause cyanocobalamin (vitamin B12) malabsorption, but measuring serum B12 alone may underestimate the prevalence. However, B12 deficiency elevates methylmalonic acid and homocysteine, both additional markers of B12 deficiency.

AIM

To determine the true prevalence of B12 deficiency and whether acid suppression by PPI caused it.

METHODS

Sixty-one acid hypersecretors (basal acid output >15 mmol/h), 46 with gastrinoma [Zollinger-Ellison (ZE) syndrome] and 15 without [acid hypersecretor without gastrinoma (pseudo-ZE)], were treated with lansoprazole to determine its long-term (up to 18 years) pharmacological and clinical efficacy and safety, particularly as regards malabsorption of B12.

RESULTS

Of 61 patients, six (10%) had low serum B12. Additional tests uncovered B12 deficiency in 13 (31%) of 41 still-available patients, despite normal serum B12. B12 replacement reduced elevated homocysteine and methylmalonic acid, supporting the diagnosis. Also, measuring both basal and stimulated gastric secretion, we found that acid suppression was neither prolonged nor profound enough to explain the B12 deficiency.

CONCLUSIONS

In long-term recipients of PPIs, B12 deficiency was more frequent (29%) than detected by measuring only serum B12, and there was not enough acid suppression to explain this deficiency.

Prevalence of and risk factors for vitamin B(12) deficiency in patients with Crohn's disease

BACKGROUND

Crohn's disease (CD) can commonly involve the terminal ileum, which is the site of B(12) absorption. The aim of this study was to define the prevalence of vitamin B(12) abnormalities in a population with CD and to identify risk factors associated with B(12) abnormalities in CD.

METHODS

The medical records of 201 patients with CD evaluated at a tertiary care center were retrospectively reviewed to determine the prevalence of B(12) deficiency and to evaluate factors associated with B(12) deficiency. The prevalence of B(12) deficiency in a control population of 40 patients with ulcerative colitis was also assessed.

RESULTS

The prevalence of an abnormal serum B(12) concentration in patients with CD was 18.4% (95% confidence interval [CI] 13.1-23.8%) compared with 5% (95% CI, 0-11.8%) (P = 0.035) in ulcerative colitis controls. Risk factors for B(12) deficiency in patients with CD included prior ileal (odds ratio [OR], 7.22; 95% CI, 1.97-26.51) or ileocolonic (OR, 5.81; 95% CI, 2.09-16.12) resection and the need for ongoing medical therapy (OR, 2.59; 95% CI, 1.03-6.47). Neither disease location nor duration was independently associated with the risk of B(12) deficiency.

CONCLUSIONS

Vitamin B(12) abnormalities are common in patients with CD and patients with a prior ileal or ileocolonic resection are at particular risk. Routine screening for B(12) deficiency in patients with CD is warranted.

Age-associated B vitamin deficiency as a determinant of chronic diseases

The number of elderly individuals is growing rapidly worldwide and degenerative diseases constitute an increasing problem in terms of both public health and cost. Nutrition plays a role in the ageing process and there has been intensive research during the last decade on B vitamin-related risk factors in vascular and neurological diseases and cancers. Data from epidemiological studies indicate that subclinical deficiency in most water-soluble B vitamins may occur gradually during ageing, possibly due to environmental, metabolic, genetic, nutritional and pathological determinants, as well as to lifestyle, gender and drug consumption. Older adults have distinct absorption, cell transport and metabolism characteristics that may alter B vitamin bioavailability. Case–control and longitudinal studies have shown that, concurrent with an insufficient status of certain B vitamins, hyperhomocysteinaemia and impaired methylation reactions may be some of the mechanisms involved before a degenerative pathology becomes evident. The question that arises is whether B vitamin inadequacies contribute to the development of degenerative diseases or result from ageing and disease. The present paper aims to give an overview of these issues at the epidemiological, clinical and molecular levels and to discuss possible strategies to prevent B vitamin deficiency during ageing.

Vitamin B(12) and methylmalonic acid levels in patients presenting with polyneuropathy

This study was designed to determine the prevalence of definite vitamin B(12) deficiency (defined as < or =240 pg/ml) and possible vitamin B(12) deficiency (defined as >240 pg/ml and a methylmalonic acid [MMA] level >243 nmol/L) in patients with polyneuropathy and to determine whether patients in both groups respond to vitamin B(12) repletion. We performed a retrospective cohort study of 581 patients presenting with polyneuropathy over a 2-year period; 4% had definite vitamin B(12) deficiency and 32% had possible deficiency as the sole or contributing cause for their polyneuropathy. For those who received treatment with vitamin B(12), subjective improvement was seen in 87% with definite and in 43% with possible deficiency. Possible vitamin B(12) deficiency, defined as an elevated MMA level, is a common finding in patients with polyneuropathy and treatment of these patients with vitamin B(12) may lead to clinical improvement.

Life-threatening megaloblastic pancytopenia with normal mean cell volume: Case series

The mean red blood cell volume (MCV) is usually increased in severe megaloblastic anemia due to pernicious anemia. However, during one year in a university hospital, three patients with life-threatening pancytopenia and normal MCV were proven to have severe vitamin B12 deficiency. The red blood cell distribution width was markedly increased (three times normal) and led to review of the blood smear and recognition of megaloblastosis as well as prominent red cell fragmentation. These three cases illustrate that vitamin B12 status should be evaluated in cases of pancytopenia, independent of the MCV value.

Folate and vitamin B12: friendly or enemy nutrients for the elderly

In the UK vitamin B12deficiency occurs in approximately 20% of adults aged >65 years. This incidence is significantly higher than that among the general population. The reported incidence invariably depends on the criteria of deficiency used, and in fact estimates rise to 24% and 46% among free-living and institutionalised elderly respectively when methylmalonic acid is used as a marker of vitamin B12status. The incidence of, and the criteria for diagnosis of, deficiency have drawn much attention recently in the wake of the implementation of folic acid fortification of flour in the USA. This fortification strategy has proved to be extremely successful in increasing folic acid intakes pre-conceptually and thereby reducing the incidence of neural-tube defects among babies born in the USA since 1998. However, in successfully delivering additional folic acid to pregnant women fortification also increases the consumption of folic acid of everyone who consumes products containing flour, including the elderly. It is argued that consuming additional folic acid (as ‘synthetic’ pteroylglutamic acid) from fortified foods increases the risk of ‘masking’ megaloblastic anaemia caused by vitamin B12deficiency. Thus, a number of issues arise for discussion. Are clinicians forced to rely on megaloblastic anaemia as the only sign of possible vitamin B12deficiency? Is serum vitamin B12alone adequate to confirm vitamin B12deficiency or should other diagnostic markers be used routinely in clinical practice? Is the level of intake of folic acid among the elderly (post-fortification) likely to be so high as to cure or ‘mask’ the anaemia associated with vitamin B12deficiency?