The prevalence of low serum vitamin B-12 status in the absence of anemia or macrocytosis did not increase among older U.S. adults after mandatory folic acid fortification

An examination of relationships between vitamin B12 status and functional measures of peripheral neuropathy in young adult vegetarians

Introduction

Prevalence rates for vitamin B12 deficiency in U.S. adult vegetarians may exceed 30%, which is concerning given the role for this vitamin in numerous nervous system functions, including the synthesis of myelin sheaths. Defective myelin synthesis and repair are directly linked to peripheral neuropathy; yet, few investigations have examined how physical indicators of peripheral neuropathy (e.g., hand dexterity, vibration sensitivity and balance) are impacted in individuals adhering to vegetarian diets. This feasibility research explored the relationships between peripheral neuropathy and vitamin B12 status using a cross-sectional study design. In addition, a small pilot trial was conducted for limited-efficacy testing of vitamin B12 supplementation for reducing peripheral neuropathy.

Methods

Healthy, able-bodied adults (n = 38; 19-40 years of age) reported exclusive adherence to a vegetarian or vegan diet for 3 years. Peripheral neuropathy was measured using a force plate for assessing balance, and a vibration sensitivity tester and pegboard tests to assess hand dexterity. Serum vitamin B12 and folate were measured using standard radioimmunoassay techniques.

Results

Twenty-six percent of the sample displayed deficient or marginal vitamin B12 status (serum vitamin B12 <221 pmol/L). Participants with adequate vitamin B12 status scored 10% higher on the Purdue pegboard assembly test and 20% higher on the left hand adjusted functional dexterity test in comparison to participants with marginal-to-deficient vitamin B12 status (p < 0.05).

Discussion

These data provide preliminary evidence that peripheral neuropathy can be detected in individuals with marginal-to-deficient vitamin B12 status.

Folic Acid and the Prevention of Birth Defects: 30 Years of Opportunity and Controversies

For three decades, the US Public Health Service has recommended that all persons capable of becoming pregnant consume 400 μg/day of folic acid (FA) to prevent neural tube defects (NTDs). The neural tube forms by 28 days after conception. Fortification can be an effective NTD prevention strategy in populations with limited access to folic acid foods and/or supplements. This review describes the status of mandatory FA fortification among countries that fortify (n = 71) and the research describing the impact of those programs on NTD rates (up to 78% reduction), blood folate concentrations [red blood cell folate concentrations increased ∼1.47-fold (95% CI, 1.27, 1.70) following fortification], and other health outcomes. Across settings, high-quality studies such as those with randomized exposures (e.g., randomized controlled trials, Mendelian randomization studies) are needed to elucidate interactions of FA with vitamin B12 as well as expanded biomarker testing.

Efficacy of 4.0 mg versus 0.4 mg Folic Acid Supplementation on the Reproductive Outcomes: A Randomized Controlled Trial

Folic acid (FA) supplementation prevents neural tube defects (NTDs), but the effects on other reproductive outcomes are unclear. While common recommendation is 0.4 mg/day in addition to regular nutrition, the most appropriate dose of FA is still under debate. We investigated the effects of a higher dose of periconception FA on reducing adverse reproductive outcomes. In this multicenter double-blind randomized controlled trial (RCT), 1060 women (aged 18-44 years and planning a pregnancy) were randomly assigned to receive 4.0 mg or 0.4 mg of FA daily. The primary outcome was the occurrence of congenital malformations (CMs). A composite outcome including one or more adverse pregnancy outcomes was also evaluated. A total of 431 women had a natural conception within 1 year. The primary outcome occurred in 8/227 (3.5%) women receiving 4.0 mg FA and 9/204 (4.4%) women receiving 0.4 mg FA (RR 0.80; 95%CI 0.31 to 2.03). The composite outcome occurred in 43/227 (18.9%) women receiving 4.0 mg FA and 75/204 (36.8%) women receiving 0.4 mg FA (RR 0.51; 95%CI 0.40 to 0.68). FA 4.0 mg supplementation was not associated with different occurrence of CMs, compared to FA 0.4 mg supplementation. However, FA 4.0 mg supplementation was associated with lower occurrence of other adverse pregnancy outcomes.

B vitamin blood concentrations and one-carbon metabolism polymorphisms in a sample of Italian women and men attending a unit of transfusion medicine: a cross-sectional study

PURPOSE

To define blood status of folate, vitamin B12, vitamin B6, homocysteine, and major one-carbon metabolism-related polymorphisms in healthy, males and females blood donors, aged 18-65 years were evaluated. General characteristics and lifestyle factors were also investigated.

METHODS

An explorative cross-sectional study design was used to evaluate a sample of blood donors attending the Unit of Transfusion Medicine of the Verona University Hospital, Italy. From April 2016 to May 2018, 499 subjects were enrolled (255 men, 244 women of whom 155 of childbearing age). Major clinical characteristics including lifestyle and dietary habits, B vitamins and homocysteine were analyzed. The MTHFR 677 C>T, cSHMT 1420 C>T, DHFR 19 bp ins/del, RFC1 80 G>A polymorphisms were also determined.

RESULTS

Mean plasma concentrations of folate, vitamin B12, vitamin B6 and homocysteine were 14.2 nmol/L (95% CI 13.7-14.8), 271.9 pmol/L (95% CI 262.6-281.5), 51.0 nmol/L (95% CI 48.7-53.4) and 13.5 µmol/L (95% CI 13.1-14.0), respectively. Plasma folate, was adequate (> 15 nmol/L) in 44.7% of all subjects, 39.0% of males and 42.5% of women < 45 years. Similarly, vitamin B12 was adequate (> 350 pmol/L) in 25.1% of all subjects and in 20.3% of men ≥ 45 years. The rare allele frequencies were 0.21 for MTHFR 677TT, 0.11 for cSHMT 1420TT, 0.18 for DHFR 19 bp del/del, 0.20 for RFC1 80AA, and a gene-nutrient interaction was confirmed for folate concentrations according to MTHFR 677C>T and DHFR 19 bp del/del.

CONCLUSION

An Italian sample of healthy blood donors shows that an adequate concentration of plasma folate and vitamin B12 is reached only in a limited percentage of subjects, thus encouraging consideration for specific public health strategies.

Modelling the impact of mandatory folic acid fortification of bread or flour in Ireland on the risk of occurrence of NTD-affected pregnancies in women of childbearing age and on risk of masking vitamin B12 deficiency in older adults

PURPOSE

The rate of neural tube defects (NTDs) in Europe has remained similar since the 1990s despite folic acid supplement recommendations (400 µg/day) for women of childbearing age. Mandatory folic acid fortification of staple foods has proved effective for reducing the prevalence of NTDs in over 80 countries. This study estimated the impact of addition of folic acid to bread or flour in the Republic of Ireland on reducing the risk of occurrence of NTD-affected pregnancies and the possible risk of masking (undiagnosed) vitamin B₁₂ deficiency in older adults.

METHODS

Analyses were based on the Irish National Adult Nutrition Survey (2008-2010). Folic acid fortification was modelled using DaDiet© software. Estimates were made of the increase in average daily folic acid intake in women (18-50 years) and the risk of exceeding the tolerable upper intake level (UL) of 1000 µg for folic acid in adults over 50 years of age.

RESULTS

The fortification scenarios examined would reduce the risk of NTD-affected pregnancies by 8-32%, corresponding to an increase of 39-152 μg in the mean daily folic acid intake of WCBA. The risk of masking anaemia associated with vitamin B₁₂ deficiency in older adults would be negligible as the probability of exceeding the UL for folic acid, even by a small amount, is very low (≤ 0.2%).

CONCLUSIONS

These levels of addition of folic acid to bread or flour would effectively reduce the risk of NTDs while allowing safe consumption of folic acid at current levels from other fortified foods and supplements.

Lack of historical evidence to support folic acid exacerbation of the neuropathy caused by vitamin B12 deficiency

In 1998 a Tolerable Upper Intake Level (UL) for folic acid was established based on case reports from the 1940s suggesting that high-dosage folic acid intake, used to treat patients with pernicious anemia, had the potential to precipitate or speed-up the development of neurological problems. This UL has been employed in the decision-making process used by more than 80 countries to establish programs to fortify staple foods with folic acid to prevent neural tube birth defects. Some have claimed that this UL is flawed and has become an obstacle to the wider adoption of neural tube defect prevention programs and have called for re-evaluation of the scientific validity of this UL. Case reports cannot establish causality, but they can reveal patterns in the timing of the onset and treatment of patients with pernicious anemia. These patterns can be compared with secular trends of usual medical practice for the treatment of pernicious anemia and with the changes in usage of folic acid preparations, including recommended therapeutic dosage and precautions for its usage surrounding the synthesis of folic acid in 1945 and vitamin B12 in 1948. Folic acid package inserts, early editions of hematology textbooks, and international expert reports provide valuable historical information. The recommended therapeutic daily dosage for folic acid of 5-20 mg was unchanged from 1946 through to 1971. The likely cause of the neurological problems encountered is the development of vitamin B12 neuropathy when pernicious anemia was treated with high-dosage folic acid before vitamin B12 was widely available in the early 1950s. Thus, the historical record does not provide compelling evidence that folic acid can potentially cause neurologic complications among those with low vitamin B12 status and lends support for reconsidering the basis for the UL of folic acid.

Fortification of wheat and maize flour with folic acid for population health outcomes

BACKGROUND

Folate is a B-vitamin required for DNA synthesis, methylation, and cellular division. Wheat and maize (corn) flour are staple crops consumed widely throughout the world and have been fortified with folic acid in over 80 countries to prevent neural tube defects. Folic acid fortification may be an effective strategy to improve folate status and other health outcomes in the overall population.

OBJECTIVES

To evaluate the health benefits and safety of folic acid fortification of wheat and maize flour (i.e. alone or in combination with other micronutrients) on folate status and health outcomes in the overall population, compared to wheat or maize flour without folic acid (or no intervention).

SEARCH METHODS

We searched the following databases in March and May 2018: Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and MEDLINE In Process, Embase, CINAHL, Web of Science (SSCI, SCI), BIOSIS, Popline, Bibliomap, TRoPHI, ASSIA, IBECS, SCIELO, Global Index Medicus-AFRO and EMRO, LILACS, PAHO, WHOLIS, WPRO, IMSEAR, IndMED, and Native Health Research Database. We searched the International Clinical Trials Registry Platform and ClinicalTrials.gov for ongoing or planned studies in June 2018, and contacted authors for further information.

SELECTION CRITERIA

We included randomised controlled trials (RCTs), with randomisation at the individual or cluster level. We also included non-RCTs and prospective observational studies with a control group; these studies were not included in meta-analyses, although their characteristics and findings were described. Interventions included wheat or maize flour fortified with folic acid (i.e. alone or in combination with other micronutrients), compared to unfortified flour (or no intervention). Participants were individuals over two years of age (including pregnant and lactating women), from any country.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed study eligibility, extracted data, and assessed risk of bias.

MAIN RESULTS

We included 10 studies: four provided data for quantitative analyses (437 participants); five studies were randomised trials (1182 participants); three studies were non-RCTs (1181 participants, 8037 live births); two studies were interrupted time series (ITS) studies (1 study population of 2,242,438, 1 study unreported). Six studies were conducted in upper-middle-income countries (China, Mexico, South Africa), one study was conducted in a lower-middle-income country (Bangladesh), and three studies were conducted in a high-income country (Canada). Seven studies examined wheat flour fortified with folic acid alone or with other micronutrients. Three studies included maize flour fortified with folic acid alone or with other micronutrients. The duration of interventions ranged from two weeks to 36 months, and the ITS studies included postfortification periods of up to seven years. Most studies had unclear risk of bias for randomisation, blinding, and reporting, and low/unclear risk of bias for attrition and contamination.Neural tube defects: none of the included RCTs reported neural tube defects as an outcome. In one non-RCT, wheat flour fortified with folic acid and other micronutrients was associated with significantly lower occurrence of total neural tube defects, spina bifida, and encephalocoele, but not anencephaly, compared to unfortified flour (total neural tube defects risk ratio (RR) 0.32, 95% confidence interval (CI) 0.21 to 0.48; 1 study, 8037 births; low-certainty evidence).Folate status: pregnant women who received folic acid-fortified maize porridge had significantly higher erythrocyte folate concentrations (mean difference (MD) 238.90 nmol/L, 95% CI 149.40 to 328.40); 1 study, 38 participants; very low-certainty evidence) and higher plasma folate (MD 14.98 nmol/L, 95% CI 9.63 to 20.33; 1 study, 38 participants; very low-certainty evidence), compared to no intervention. Women of reproductive age consuming maize flour fortified with folic acid and other micronutrients did not have higher erythrocyte folate (MD -61.80 nmol/L, 95% CI -152.98 to 29.38; 1 study, 35 participants; very low-certainty evidence) or plasma folate (MD 0.00 nmol/L, 95% CI -0.00 to 0.00; 1 study, 35 participants; very low-certainty evidence) concentrations, compared to women consuming unfortified maize flour. Adults consuming folic acid-fortified wheat flour bread rolls had higher erythrocyte folate (MD 0.66 nmol/L, 95% CI 0.13 to 1.19; 1 study, 30 participants; very low-certainty evidence) and plasma folate (MD 27.00 nmol/L, 95% CI 15.63 to 38.37; 1 study, 30 participants; very low-certainty evidence), versus unfortified flour. In two non-RCTs, serum folate concentrations were significantly higher among women who consumed flour fortified with folic acid and other micronutrients compared to women who consumed unfortified flour (MD 2.92 nmol/L, 95% CI 1.99 to 3.85; 2 studies, 657 participants; very low-certainty evidence).Haemoglobin or anaemia: in a cluster-randomised trial among children, there were no significant effects of fortified wheat flour flatbread on haemoglobin concentrations (MD 0.00 nmol/L, 95% CI -2.08 to 2.08; 1 study, 334 participants; low-certainty evidence) or anaemia (RR 1.07, 95% CI 0.74 to 1.55; 1 study, 334 participants; low-certainty evidence), compared to unfortified wheat flour flatbread.

AUTHORS' CONCLUSIONS

Fortification of wheat flour with folic acid may reduce the risk of neural tube defects; however, this outcome was only reported in one non-RCT. Fortification of wheat or maize flour with folic acid (i.e. alone or with other micronutrients) may increase erythrocyte and serum/plasma folate concentrations. Evidence is limited for the effects of folic acid-fortified wheat or maize flour on haemoglobin levels or anaemia. The effects of folic acid fortification of wheat or maize flour on other primary outcomes assessed in this review is not known. No studies reported on the occurrence of adverse effects. Limitations of this review were the small number of studies and participants, limitations in study design, and low-certainty of evidence due to how included studies were designed and reported.

Rapid healing of a patient with dramatic subacute combined degeneration of spinal cord: a case report

Background

Prevalence of cobalamin deficiency is high especially in older patients and an immediate therapy start is necessary to prevent irreversible neurological damages. Unfortunately, the diagnosis of cobalamin deficiency is difficult and at present, there is no consensus for diagnosis of this deficiency. Therefore, we aim to elucidate a meaningful diagnostic pathway by a case report with an initially misleading medical history.

Case presentation

A 57 year-old Caucasian man suffering from dramatic myelosis of the cervical posterior columns. Apart from associated neurological symptoms (tactile hypaesthesia, reduced vibration sensation, loss of stereognosis and of two-point-discrimination) there were no further complaints; especially no gastrointestinal, haematological or psychiatric disorders were provable. Cobalamin (vitamin B12) serum level was normal. The diagnosis of subacute combined degeneration of spinal cord was confirmed by an elevated methylmalonic acid, and hyperhomocysteinemia. Cobalamin deficiency was caused by asymptomatic chronic atrophic inflammation of the stomach with a lack of intrinsic factor producing gland cells. This was revealed by increased gastrin and parietal cell antibodies and finally confirmed by gastroscopy. Parenteral substitution of cobalamin rapidly initiated regeneration.

Conclusions

This case demonstrates that normal cobalamin serum levels do not rule out a cobalamin deficiency. In contrast, path-breaking results can be achieved by determining homocysteine, holotranscobalamin, and methylmalonic acid.

Interaction between excess folate and low vitamin B12 status

Current epidemiological evidence suggests that an imbalance of high folate status and low vitamin B12 status is associated with negative health outcomes in older adults and children. Such an imbalance during pregnancy also predisposes women to diabetes and their offspring to insulin resistance and adiposity and low birthweight. In older adults, vitamin B12 status can remain low despite adequate intake due to age-related decline in vitamin B12 absorption. Pregnant women are exposed to folic acid at varying doses depending on the prenatal care prescribed in different countries. This review summarizes the current knowledge on the interaction between folate and vitamin B12 and the associated health outcomes.

Causes, Consequences and Public Health Implications of Low B-Vitamin Status in Ageing

The potential protective roles of folate and the metabolically related B-vitamins (vitamins B12, B6 and riboflavin) in diseases of ageing are of increasing research interest. The most common cause of folate and riboflavin deficiencies in older people is low dietary intake, whereas low B12 status is primarily associated with food-bound malabsorption, while sub-optimal vitamin B6 status is attributed to increased requirements in ageing. Observational evidence links low status of folate and the related B-vitamins (and/or elevated concentrations of homocysteine) with a higher risk of degenerative diseases including cardiovascular disease (CVD), cognitive dysfunction and osteoporosis. Deficient or low status of these B-vitamins alone or in combination with genetic polymorphisms, including the common MTHFR 677 C → T polymorphism, could contribute to greater disease risk in ageing by causing perturbations in one carbon metabolism. Moreover, interventions with the relevant B-vitamins to optimise status may have beneficial effects in preventing degenerative diseases. The precise mechanisms are unknown but many have been proposed involving the role of folate and the related B-vitamins as co-factors for one-carbon transfer reactions, which are fundamental for DNA and RNA biosynthesis and the maintenance of methylation reactions. This review will examine the evidence linking folate and related B-vitamins with health and disease in ageing, associated mechanisms and public health implications.

Diagnostic value of blood tests for occult causes of initially idiopathic small-fiber polyneuropathy

Small-fiber polyneuropathy (SFPN) causes non-specific symptoms including chronic pain, cardiovascular, gastrointestinal, and sweating complaints. Diagnosis is made from history and exam in patients with known risk factors such as diabetes, but objective test confirmation is recommended for patients without known risks. If tests confirm SFPN, and it is "initially idiopathic" (iiSFPN), screening for occult causes is indicated. This study's aim was to evaluate the 21 widely available, recommended blood tests to identify the most cost-effective ones and to learn about occult causes of iiSFPN. Records were reviewed from all 213 patients with SFPN confirmed by distal-leg skin biopsy, nerve biopsy, or autonomic-function testing in our academic center during 2013. We determined the prevalence of each abnormal blood-test result (ABTR) in the iiSFPN cohort, compared this to population averages, and measured the costs of screening subjects to obtain one ABTR. Participants were 70 % female and aged 43.0 ± 18.6 years. High erythrocyte sedimentation rate (ESR) and antinuclear antibody (ANA; ≥1:160 titer) were most common, each present in 28 % of subjects. The ABTR ≥3 × more prevalent in iiSFPN than in the total population were high ESR, high ANA, low C3, and Sjögren's and celiac autoantibodies. Together, these suggest the possibility of a specific association between iiSFPN and dysimmunity. ABTR identifying diabetes, prediabetes, and hypertriglyceridemia were less common in iiSFPN than in the population and thus were not associated with iiSFPN here. The six most cost-effective iiSFPN-associated blood tests-ESR, ANA, C3, autoantibodies for Sjögren's and celiac, plus thyroid-stimulating hormone-had estimated cost of $99.57/person and 45.6 % probability of obtaining one abnormal result. Angiotensin-converting enzyme was elevated in 45 %, but no patients had sarcoidosis, so this test was futile here.

Folate and neural tube defects: The role of supplements and food fortification

Periconceptional folic acid significantly reduces the risk of neural tube defects. It is difficult to achieve optimal levels of folate by diet alone, even with fortification of flour, especially because flour consumption in Canada is slightly decreasing. Intermittent concerns have been raised concerning possible deleterious effects of folate supplementation, including the masking of symptoms of vitamin B12 deficiency and an association with cancer, especially colorectal cancer. Both concerns have been disproved. The Canadian Paediatric Society endorses the following steps to enhance folate intake in women of child-bearing age: encouraging the consumption of folate-rich foods such as leafy vegetables, increasing the level of folate food fortification, taking a supplement containing folate and B12, and providing free folate supplementation to disadvantaged women of child-bearing age. These recommendations are consistent with those of the Society of Obstetricians and Gynaecologists of Canada.

Retrospective Assessment of Cost Savings From Prevention: Folic Acid Fortification and Spina Bifida in the U.S

INTRODUCTION

Although fortification of food with folic acid has been calculated to be cost saving in the U.S., updated estimates are needed. This analysis calculates new estimates from the societal perspective of net cost savings per year associated with mandatory folic acid fortification of enriched cereal grain products in the U.S. that was implemented during 1997-1998.

METHODS

Estimates of annual numbers of live-born spina bifida cases in 1995-1996 relative to 1999-2011 based on birth defects surveillance data were combined during 2015 with published estimates of the present value of lifetime direct costs updated in 2014 U.S. dollars for a live-born infant with spina bifida to estimate avoided direct costs and net cost savings.

RESULTS

The fortification mandate is estimated to have reduced the annual number of U.S. live-born spina bifida cases by 767, with a lower-bound estimate of 614. The present value of mean direct lifetime cost per infant with spina bifida is estimated to be $791,900, or $577,000 excluding caregiving costs. Using a best estimate of numbers of avoided live-born spina bifida cases, fortification is estimated to reduce the present value of total direct costs for each year's birth cohort by $603 million more than the cost of fortification. A lower-bound estimate of cost savings using conservative assumptions, including the upper-bound estimate of fortification cost, is $299 million.

CONCLUSIONS

The estimates of cost savings are larger than previously reported, even using conservative assumptions. The analysis can also inform assessments of folic acid fortification in other countries.

B Vitamins and the Brain: Mechanisms, Dose and Efficacy--A Review

The B-vitamins comprise a group of eight water soluble vitamins that perform essential, closely inter-related roles in cellular functioning, acting as co-enzymes in a vast array of catabolic and anabolic enzymatic reactions. Their collective effects are particularly prevalent to numerous aspects of brain function, including energy production, DNA/RNA synthesis/repair, genomic and non-genomic methylation, and the synthesis of numerous neurochemicals and signaling molecules. However, human epidemiological and controlled trial investigations, and the resultant scientific commentary, have focused almost exclusively on the small sub-set of vitamins (B9/B12/B6) that are the most prominent (but not the exclusive) B-vitamins involved in homocysteine metabolism. Scant regard has been paid to the other B vitamins. This review describes the closely inter-related functions of the eight B-vitamins and marshals evidence suggesting that adequate levels of all members of this group of micronutrients are essential for optimal physiological and neurological functioning. Furthermore, evidence from human research clearly shows both that a significant proportion of the populations of developed countries suffer from deficiencies or insufficiencies in one or more of this group of vitamins, and that, in the absence of an optimal diet, administration of the entire B-vitamin group, rather than a small sub-set, at doses greatly in excess of the current governmental recommendations, would be a rational approach for preserving brain health.

Contemporary issues surrounding folic Acid fortification initiatives

The impact of folate on health and disease, particularly pregnancy complications and congenital malformations, has been extensively studied. Mandatory folic acid fortification therefore has been implemented in multiple countries, resulting in a reduction in the occurrence of neural tube defects. However, emerging evidence suggests increased folate intake may also be associated with unexpected adverse effects. This literature review focuses on contemporary issues of concern, and possible underlying mechanisms as well as giving consideration the future direction of mandatory folic acid fortification. Folate fortification has been associated with the presence of unmetabolized folic acid (PteGlu) in blood, masking of vitamin B12 deficiency, increased dosage for anti-cancer medication, photo-catalysis of PteGlu leading to potential genotoxicity, and a role in the pathoaetiology of colorectal cancer. Increased folate intake has also been associated with twin birth and insulin resistance in offspring, and altered epigenetic mechanisms of inheritance. Although limited data exists to elucidate potential mechanisms underlying these issues, elevated blood folate level due to the excess use of PteGlu without consideration of an individual's specific phenotypic traits (e.g. genetic background and undiagnosed disease) may be relevant. Additionally, the accumulation of unmetabolized PteGlu may lead to inhibition of dihydrofolate reductase and other enzymes. Concerns notwithstanding, folic acid fortification has achieved enormous advances in public health. It therefore seems prudent to target and carefully monitor high risk groups, and to conduct well focused further research to better understand and to minimize any risk of mandatory folic acid fortification.