Vitamin B12 Status Research Articles

The Status of B Vitamin in Saudi Adults: A Review

Background and Objective: B vitamins are essential for maintaining several body functions. Assessing micronutrient status in a population is crucial for evaluating the individual or the population’s levels of nutrient sufficiency, deficiency, or toxicity; examining the relationship between a nutrient’s status and adverse health outcomes; and determining nutrient needs to establish reference values. There is lack of periodical national surveys in Saudi Arabia that assess the status of the B vitamins. Therefore, this review summarizes and critique the literature of B vitamin status in Saudi adults age of ≥18 years. Methods and Study Design: Databases (PubMed, Medline and Google Scholar) were searched for articles published between January 1980 to December 2022 using combinations of the terms “Saudi Arabia”, “status”, “level” along with all the corresponding vitamin B keywords and metabolites. Results: Forty three studies were obtained. Only 28 studies were included to the current review. Several studies conducted in Saudi adults measured folate and vitamin B12 status. Fewer studies assessed thiamine, riboflavin, and pyridoxine status. No relevant studies were found on the status of niacin, pantothenic acid, and biotin. Studies on thiamin status have not reported rates of deficiency except for one study reporting a prevalence of 3%. Conflicting findings were observed for riboflavin status, but the most recent evidence suggests a prevalence of 36.9% deficiency among Saudi adults. Folate deficiency appears to be low, whereas vitamin B12 might be of concern among Saudi adults. Conclusions: There were discrepancies in the results of some vitamin status in Saudi adults mainly attributed to differences in biomarkers used, methodologies, regional differences, and/or age group/population.

Distribution and status of vitamin B12 in Chinese adults with hypertension: a comprehensive report across 14 provinces

Background: Vitamin B12 (VB12) is an essential biomarker for population health, and its deficiency status leads to severe health burdens. A comprehensive and updated investigation on the distribution of VB12 levels and status is critically needed to address public health and clinical concerns. Methods: We conducted a cross-sectional analysis using data obtained from the Precision Medical Program, which encompassed 14 provinces in China. Specific criteria based on previously published cutoffs and our study population’s characteristics are adopted to define B12 deficiency. Biochemical B12 deficiency was identified with circulating VB12 levels <148 pmol/L. Metabolic B12 deficiency was determined with circulating VB12 levels ≥148 and ≤258 pmol/L with concomitant elevated plasma total homocysteine (tHcy ≥14 µmol/L). Normal B12 status included VB12 levels >258 pmol/L or VB12 levels ranging from 148 to 258 pmol/L with tHcy levels below 14 µmol/L. VB12 levels and status were analyzed and stratified by age, sex, and geographical region. Results: This study enrolled a total of 2174 hypertensive adults, with a mean age of 63.0 years (±13.4) and 45.8% female. The overall mean VB12 levels were 322.3 (85.0) pmol/L. The prevalence rates of B12 biochemical deficiency, metabolic deficiency, metabolic deficiency with excluded renal dysfunction, and adequate status were 0.7%, 13.3%, 11.5%, and 85.9%, respectively. Females exhibited higher VB12 levels than males, with a β value of 19.72 (95% confidence interval [CI], 10.59–28.84) in the multivariate model. The southern population demonstrated higher VB12 levels than people from the north, with a β value of −18.14 (95% CI, −25.72 to −10.76). Males had a higher prevalence of metabolic VB12 deficiency in comparison to females (15.8% vs. 10.4%). Conclusions: Our study revealed that Chinese hypertensive adults exhibit relatively higher levels of VB12. Additionally, while biochemical B12 deficiency is uncommon, a noteworthy proportion of individuals were affected by metabolic VB12 deficiency. This study has important implications for nutritional counseling and vitamin B supplement strategies.

Micronutrient Status in Pregnant Women after Metabolic Bariatric Surgery in the United Arab Emirates: A Prospective Study.

Metabolic bariatric surgery (MBS) helps reduce comorbidities, such as hypertension and gestational diabetes, and is more effective than diet management for women with obesity-related health issues. Vitamin B12, vitamin D, and iron play important roles in ensuring the health of a neonate. However, pregnancies occurring after MBS may face complications related to micronutrient deficiencies, particularly of vitamins B12 and D and iron. This study aimed to investigate the vitamin B12, vitamin D, ferritin, and iron status of pregnant women who underwent MBS compared with women without MBS history. The study included 217 pregnant women (105 with a history of MBS and 112 without a history of MBS) who visited a major maternity hospital in Abu Dhabi, United Arab Emirates (UAE) between July 2021 and November 2022. The maternal vitamin B12, vitamin D, iron, and ferritin levels were measured twice, initially during the first or second trimester and subsequently during the third trimester. The iron was measured once during the pregnancy. Vitamin B12 deficiency was higher among pregnant women with MBS history compared to non-bariatric pregnant women (24.4% vs. 3.9%, p < 0.001). Women with a history of MBS had a higher prevalence of vitamin D deficiency (62.3% vs. 37.7%, p < 0.002). Linear regression analysis indicated that vitamin B12 levels decreased by 55 pg/mL in women with a history of MBS and by 4.6 pg/mL with a unit increase in body mass index (kg/m2). Furthermore, vitamin D levels in women with a history of MBS decreased by 4.9 ng/mL during pregnancy. Metabolic bariatric surgery is associated with vitamin B12, vitamin D, and iron deficiencies during pregnancy.

Riboflavin: a scoping review for Nordic Nutrition Recommendations 2023.

Only a few studies have explored relationships between riboflavin intake and function and a few studies have examined the effects of supplements on various clinical or biochemical outcomes. None of these studies, however, make a useful contribution to understanding requirements in healthy populations. Thus, there is no strong evidence to change the recommendations. The requirement for riboflavin is estimated based on the relationship between intake and biochemical indices of riboflavin status, including urinary excretion and enzyme activities.

Vitamin B6: a scoping review for Nordic Nutrition Recommendations 2023.

Pyridoxal 5´-phosphate (PLP) is the main form of vitamin B6 in animal tissue and functions as a coenzyme for more than 160 different enzymatic reactions in the metabolism of amino acids, carbohydrates, lipids, and neurotransmitters. Estimated dietary intake of vitamin B6 and plasma PLP values differ a lot between studies, something which may be due to variable use of supplements, variations in dietary assessment and analytical methods. These factors make it difficult to achieve precise data for setting a correct recommended intake of vitamin B6. In addition, a plasma PLP concentration of 30 nmol/L is considered to be sufficient and the current recommendations for vitamin B6 intake is based on this concept. However, the metabolic marker for vitamin B6 status, HK ratio (HKr), starts to increase already when plasma PLP falls below 100 nmol/L and increases more steeply below 50 nmol/L, indicating biochemical deficiency. Consequently, a plasma PLP concentration of 30 nmol/L, may be too low as a marker for an adequate vitamin B6 status.

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

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

Folate, vitamin B12, and homocysteine status in the Korean population: data from the 2013-2015 Korea National Health and Nutrition Examination Survey.

We aimed to assess the serum folate, vitamin B12, and homocysteine status in Korean adolescents and adults using national data. Blood samples were collected from participants aged ≥10 years in the Korea National Health and Nutrition Examination Survey 2013-2015. The stored serum samples were used to measure folate, vitamin B12, and homocysteine concentrations. A total of 8,016 participants were included in this analysis. Unweighted descriptive statistics and adjusted geometric means of the B vitamins and homocysteine concentrations were estimated. Females had higher serum folate and vitamin B12 concentrations and lower serum homocysteine concentrations than males. Folate deficiency (<6.8 nmol/L) and hyperhomocysteinemia (>15 μmol/L) were found in 8.6% and 11.8% of males, respectively. Approximately 3% of males had low or marginally low vitamin B12 status (≤221 pmol/L). Folate and vitamin B12 deficiencies and hyperhomocysteinemia were found in <2% of females. Suboptimal folate status was prevalent among adolescents and young adults, while suboptimal vitamin B12 status and hyperhomocysteinemia were relatively higher in older adults. Adjusted mean homocysteine concentrations were sharply decreased from the first to second decile of serum folate in males. In the Korean population, the proportion of males who achieved desirable folate and homocysteine concentrations were lower than those of females. Although most Koreans have adequate vitamin B12, a suboptimal folate status is common, particularly among adolescents and young adults. These findings could establish a foundation for public health initiatives aimed at improving folate levels in the Korean population.

Relationship between hysterectomy and global DNA methylation levels in peripheral blood: an exploratory follow-up study

ObjectiveThe present study aims to understand the relationship between hysterectomy and peripheral blood leukocyte (PBL) global DNA methylation independently and in light of selected biochemicals (vitamin B12, folate, homocysteine). Material and methodsFor the present population-based follow-up study, a total of 616 women aged 30–70 years were recruited from Haryana, India. Recruited participants underwent a baseline assessment, which included the determination of menopausal and hysterectomy status and estimation of vitamin B12, folate, homocysteine, and PBL global DNA methylation (5mC) levels. The 5mC levels were analyzed using ELISA-based colorimetric technique. Participants with no history of hysterectomy were followed up after 8 years, and their current menopausal and hysterectomy statuses were determined. ResultThe median PBL 5mC level of the group with hysterectomy was found to be significantly lower than that of those without hysterectomy in the baseline assessment (PBL 5mC = 0.47 vs. 0.74, respectively; p-value = 0.016). However, there was no significant difference in baseline median PBL 5mC levels between women who eventually underwent hysterectomy and those who did not. When stratified for biochemical levels, the trend of PBL global DNA hypomethylation in the hysterectomy group, compared to the no-hysterectomy group, was statistically significant only within the normal folate group. ConclusionThis study suggests a potential association between hysterectomy (or related factors) and global DNA hypomethylation. Further research is warranted to validate the findings of the present study and to advance the existing knowledge regarding the epigenetic implications of hysterectomy.

Micronutrient Deficiency in Inherited Metabolic Disorders Requiring Diet Regimen: A Brief Critical Review

Many inherited metabolic disorders (IMDs), including disorders of amino acid, fatty acid, and carbohydrate metabolism, are treated with a dietary reduction or exclusion of certain macronutrients, putting one at risk of a reduced intake of micronutrients. In this review, we aim to provide available evidence on the most common micronutrient deficits related to specific dietary approaches and on the management of their deficiency, in the meanwhile discussing the main critical points of each nutritional supplementation. The emerging concepts are that a great heterogeneity in clinical practice exists, as well as no univocal evidence on the most common micronutrient abnormalities. In phenylketonuria, for example, micronutrients are recommended to be supplemented through protein substitutes; however, not all formulas are equally supplemented and some of them are not added with micronutrients. Data on pyridoxine and riboflavin status in these patients are particularly scarce. In long-chain fatty acid oxidation disorders, no specific recommendations on micronutrient supplementation are available. Regarding carbohydrate metabolism disorders, the difficult-to-ascertain sugar content in supplementation formulas is still a matter of concern. A ketogenic diet may predispose one to both oligoelement deficits and their overload, and therefore deserves specific formulations. In conclusion, our overview points out the lack of unanimous approaches to micronutrient deficiencies, the need for specific formulations for IMDs, and the necessity of high-quality studies, particularly for some under-investigated deficits.

Prenatal vitamin B12 status and cognitive functioning in children at 4 years of age: The ECLIPSES Study.

Maternal vitamin B12 deficiency has been associated with disturbed cognitive functioning in offspring at different ages during childhood. However, this association has not been explored in pre-school-age children. The objective of this study was to examine the association between maternal vitamin B12 levels at the beginning and end of pregnancy and cognitive functioning in their children at 4 years of age. This longitudinal prospective study included a subsample of pregnant women and their children aged 4 years (n = 249) who participated in the ECLIPSES Study conducted in the province of Tarragona, Spain, from 2013 to 2017. Maternal vitamin B12 concentrations were determined in the first and third trimesters, and sociodemographic, nutritional and psychological data were collected. The children's cognitive functioning was assessed using the Wechsler Preschool and Primary Scale of Intelligence (WPPSI-IV) and subtests of the Neuropsychological Assessment of Development (NEPSY-II). The multivariable models showed a significant relationship between vitamin B12 and the working memory index in the first trimester of the pregnancy but not in the third trimester. Children of mothers in the second vitamin B12 level tertile (314-413 pg/mL) (β = 6.468, 95% confidence interval [CI]: = 2.054, 10.882, p = 0.004) and third vitamin B12 level tertile (≥414 pg/mL) (β = 4.703, 95% CI: = 0.292, 9.114, p = 0.037) scored higher in the working memory index of the WPPSI-IV than the children of mothers with vitamin B12 levels in the first tertile (<314 pg/mL). Maintaining an adequate level of maternal vitamin B12 during early pregnancy contributes to improved performance in childhood working memory at 4 years of age.

Vitamin B12 – a scoping review for Nordic Nutrition Recommendations 2023

Vitamin B12 (cobalamin) is essential for normal metabolic function, and even moderate deficiency of this vitamin has negative health effects. Vitamin B12 is found in animal foods, and as vegetarian diets are increasingly popular in Western countries, one might expect a higher prevalence of vitamin B12 deficiency in the Nordic population. Setting recommendations for vitamin B12 intake has proven to be difficult, as uptake of vitamin B12 varies substantially, the clinical deficiency symptoms are often diffuse, and there is no clear agreement on the decision limits for vitamin B12 deficiency. Vitamin B12 deficiency is reported to be particularly common among pregnant women and infants, despite the fact that less than 1% of Norwegian pregnant women have a cobalamin intake below the Nordic Nutrition Recommendations 2012-recommended level of 2.0 µg/day. In addition, the assumption that breast milk contains sufficient vitamin B12 for optimal health and neurodevelopment during the first 6 months of life does not comply with the high prevalence of insufficient vitamin B12 status in this age group. Recommended intakes of vitamin B12 vary among age groups and must be based on markers of cobalamin status, indicating an optimal intracellular biochemical status, and not merely absence of clinical signs of vitamin B12 deficiency.

Vitamin B12 status among asymptomatic young adult females and its association with some anthropometric and biochemical parameters: A cross-sectional study from Makkah (cobalamin deficiency in young adult females).

This study was designed to measure the prevalence of vitamin B12 deficiency among young adult females in Makkah City and study its correlation with some anthropometric and biochemical indicators. A cross-sectional study and a detailed questionnaire were used to collect information from 402 young women aged 19 to 22 years, who were university students. Moreover, dietary assessments using a validated food frequency questionnaire and anthropometric measurements were performed. The mean values of serum vitamin B12, serum folate, hemoglobin, and body mass index (BMI) were 343.29 ± 148.16 pg/mL, 12.72 ± 2.62 ng/mL, 12.69 ± 1.41 g/dL, and 22.64 ± 4.24 kg/m2, respectively. About three-quarters of the study sample had normal vitamin B12 levels, while the rest had vitamin B12 deficiency. Meanwhile, a significant negative association (r = -0.201, P = .048) was found between abdominal fat and serum vitamin B12 levels. This study concluded that the young adult females' population from Makkah City is among the risk groups for vitamin B12 deficiency, which is highly correlated with inappropriate values of weight, body fat, and some blood indices. Appropriate dietary interventions and awareness are needed for this population.

The Effect of Vitamin B12 Supplementation on Leukocyte Telomere Length in Mildly Stunted Nepalese Children: A Secondary Outcome of a Randomized Controlled Trial

BackgroundVitamin B12 is essential for deoxyribonucleic acid synthesis and genome stability. A deficiency of vitamin B12 is associated with telomere shortening, genomic aging, and increased risk of chronic disease and mortality. ObjectivesThe study aims to determine the effect of vitamin B12 supplementation on leukocyte telomere length (LTL) in infants at risk of vitamin B12 deficiency. MethodsThe study was a predefined secondary analysis of a randomized controlled trial enrolling 600 Nepalese infants aged 6 –11 mo, who were supplemented with 2 μg (2–3 recommended daily allowances) vitamin B12 or placebo daily for 1 y. At the end of the study, LTL was measured in 497 participants. Mean LTL was compared between the treatment arms in the full sample and predefined subgroups based on markers of vitamin B12 status, hemoglobin, sex, and growth indices. ResultsLTL at end-study did not differ between the vitamin B12 and placebo arm with a standardized mean difference (95% confidence interval) of 0.04 (–0.14, 0.21). There was no effect of vitamin B12 on LTL in any of the subgroups. ConclusionsProviding daily vitamin B12 for 1 y during infancy in a population at risk of vitamin B12 deficiency does not affect LTL.This trial was registered at clinicaltrials.gov as NCT02272842.

Vitamin B12 and Folate Status in Pregnant Females and Their Infants in Norway: Secondary Analysis from the Mommy’s Food Study

BackgroundVitamin B12 and folate are essential micronutrients important for normal infant growth and development. ObjectivesThe aims were to describe vitamin B12 and folate status in pregnant females and their infants according to commonly used status cutoffs and examine the associations between maternal status, maternal supplement use, and breastfeeding and infant status. MethodsPregnant females were recruited at 18 wk gestation in Bergen, Norway. Maternal vitamin B12 and folate status were measured at gestational weeks 18 (n = 136) and 36 (n = 116), and infant status was measured at ages 3 (n = 73) and 6 (n = 74) mo. ResultsAt gestational weeks 18 and 36, respectively, 4.4% and 2.6% of the mothers had plasma cobalamin concentrations <148 pmol/L, 0.7% and 6.9% had methylmalonic acid (MMA) concentrations >0.26 μmol/L, and 3.7% and 30% had folate concentrations <10 nmol/L. None of the females had total homocysteine (t-Hcy) concentrations >13 μmol/L or 3 combined indicator of vitamin B12 (cB12) < −0.5. At 3 and 6 mo, respectively, 4.1% and 5.4% of the infants had cobalamin concentrations <148 pmol/L, 63% and 74% had t-Hcy concentrations >6.5 μmol/L, 59% and 66% had MMA concentrations >0.26 μmol/L, and 47% and 60% had cB12 > −0.5. None of the infants had folate concentrations <10 nmol/L. Several of the vitamin B12 biomarkers in infants were associated with maternal vitamin B12 status during pregnancy. Breastfed infants had lower vitamin B12 status (as indicated by plasma cobalamin, t-Hcy, and cB12) than nonbreastfed infants at both 3 and 6 mo. Use of supplements during pregnancy was associated with better vitamin B12 status among infants at 3 and 6 mo, as indicated by infants’ cobalamin and t-Hcy concentrations. ConclusionsSubclinical vitamin B12 deficiency among infants was common and associated with maternal vitamin B12 status during pregnancy and breastfeeding. Among the mothers, an increase in biochemical folate deficiency was discovered toward the end of gestation. Further studies are needed to investigate clinical consequences.This trial was registered at clinicaltrials.gov as NCT02610959.

A cross-sectional study of nutritional status in healthy, young, physically-active German omnivores, vegetarians and vegans reveals adequate vitamin B12 status in supplemented vegans

Background/Objective Plant-based diets reduce the risk of cardiovascular disease but also increase the risk of certain micronutrient deficiencies, particularly, of vitamin B12 (B12). The extent to which the unsupervised use of oral nutrient supplements is sufficient to prevent these deficiencies is not well established. We analyzed nutrient intake, laboratory biomarkers, supplementation behavior, and B12 status adequacy amongst young, healthy, physically active omnivores, lacto-ovo-vegetarians and vegans from Germany. Methods We recruited 115 participants (n = 40 omnivores; n = 37 lacto-ovo-vegetarians, and n = 38 vegans) with comparable age, sex, marital status, physical activity and educational levels through online advertisements and local newspapers in Freiburg, Germany. Results Energy intake and macronutrient distribution were comparable across diets. Major differences included intake of fiber, cholesterol, and several vitamins. Vegans had the lowest intake of B12 from foods (0.43 (0.58) µg/d), compared to omnivores (2.14 (2.29) µg/d) and lacto-ovo-vegetarians (0.98 (1.34) µg/day). Multivariate analysis of 36 blood biomarkers revealed that three major classes of biomarkers contributed the most to the clustering of individuals by dietary group, namely, biomarkers of B12 status (B12, holoTC, Hcy), iron (iron, ferritin, transferrin) and lipid metabolism (vitamin A, HDL, LDL, total cholesterol, TAG). This suggests that nutrients that modify the metabolic pathways represented by these biomarkers have the most penetrating effect on health status across diets. Analysis of B12 status (including 4cB12) revealed adequacy in omnivores and vegans, and a poorer B12 status amongst lacto-ovo-vegetarians. Fewer lacto-ovo-vegetarians used B12 supplements compared to vegans (51% versus 92%). Conclusions Even amongst homogeneously healthy Germans, each diet manifested with measurable differences in dietary intakes and biomarkers of health. Plant-based diets, in particular the vegan diet, exhibited the most favorable patterns of lipid metabolism and glycemic control, but the lowest food intake of B12. Supplementation of healthy vegans with B12 (median 250 µg B12/day, over 1 year) secured an adequate B12 status that was comparable to that of healthy omnivores. Clinical Trial Registry: German Clinical Trial register number: DRKS00027425

The Association Between the Imbalance of Single-Carbon Nutrients in Early Pregnancy and Gestational Diabetes Mellitus Risk is Influenced by Serum Selenium Status: A Cohort Study.

The role of imbalanced one-carbon nutrients in gestational diabetes mellitus (GDM) risk has garnered significant interest, yet existing studies yield inconsistent results. Our objective was to assess whether the association between an unbalanced ratio of folate to vitamin B12 and GDM risk is influenced by the status of other micronutrients. This cohort study included 366 singleton-pregnancy Han women enrolled at the Shunyi District Maternal and Child Health Hospital in Beijing, China. During the first trimester of pregnancy, we measured red blood cell (RBC) folate, serum levels of vitamin B12, vitamin D, and selenium. We examined the association between the imbalanced status of RBC folate and vitamin B12 and GDM risk using logistic regression, stratified by serum selenium or vitamin D status. Among the 366 women, 67 (18.3%) were diagnosed with GDM, 201 (54.9%) had vitamin D deficiency, and 245 (66.9%) had selenium deficiency. Overall, women with higher RBC folate/vitamin B12 ratios did not exhibit a significantly higher risk of GDM compared to those in reference tertile (all P > 0.05). Subsequently, we divided women into deficient and non-deficient groups based on serum selenium or vitamin D levels. In women with selenium deficiency, those in the highest tertile of the RBC folate/vitamin B12 ratio had the highest odds of GDM [OR: 3.40 (1.16-9.97), P=0.026] after adjusting for covariates. However, similar findings were not observed in pregnancies with normal selenium status. Irrespective of vitamin D status, women with higher RBC folate/vitamin B12 ratios did not exhibit a significantly increased risk of GDM. Micronutrient deficiencies are common in early pregnancy. Women with a higher folate/vitamin B12 ratio coupled with selenium deficiency in early pregnancy have a higher GDM risk. These findings underscore the importance of micronutrient assessment in early pregnancy and subsequent interventions for micronutrient deficiencies.

Lower levels of the neuroprotective tryptophan metabolite, kynurenic acid, in users of estrogen contraceptives

Changes in kynurenine metabolites are reported in users of estrogen containing contraception. We have assessed kynurenines, vitamin B6, vitamin B2 and the inflammation markers, C-reactive protein (CRP) and neopterin, in healthy, never-pregnant women between 18 and 40 years (n = 123) and related this to their use of hormonal contraception. The population included 58 women, who did not use hormonal contraceptives (non-users), 51 users of estrogen-containing contraceptives (EC-users), and 14 users of progestin only contraceptives (PC-users). EC-users had significantly lower plasma kynurenic acid (KA) and higher xanthurenic acid (XA) levels compared to non-users. Serum CRP was significantly higher and negatively associated with both vitamin B6 and B2 status in EC-user compared to non-users. No significant differences in any parameters were seen between PC-users and non-users (p > 0.1). The low KA and high XA concentration in users of estrogen containing contraception resemble the biochemical profile observed in vitamin B6 deficiency. The hormonal effect may result from interference with the coenzyme function of vitamin B6 and B2 for particular enzymes in the kynurenine metabolism. KA has been suggested to be neuroprotective and the significantly reduced concentration in EC-users may be of importance in the observed increased risk of mood disorders among users of oral contraceptives.

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

Vitamin B12 status is assessed primarily by measuring total serum B12 using competitive binding methods. The lack of availability of a standard material and high-level reference measurement procedure affect the trueness of B12 results; this results in variation between methods. This study aimed to determine the reference intervals for vitamin B12 on three routine analytical platforms. A prospective reference population of healthy individuals was recruited according to the IFCC CRIDL criteria. Vitamin B12 samples were measured on Roche, Beckman and Siemens analytical platforms. In total, 300 adult subjects were recruited; the central 95th centile values for B12 for Roche (190-678ng/mL) and Siemens (181-562ng/mL) analytical platforms were in a close agreement. Beckman DXi, however, showed a significantly lower reference limit (110-562ng/mL). All reference intervals are in keeping with previously published data but some are not in agreement with manufacturer provided reference interval. As the quality of the reference intervals plays a significant role in clinical outcome, it is of great importance that laboratories use a method-specific reference interval and if possible, locally derived reference intervals until further method standardization occurs.

Nonlinear Relationship Between Maternal and Cord Blood Vitamin B12 and Folate from a Chinese Population-Based Study.

There remains a data gap on vitamin B12 and folate level in maternal and child populations. This study aimed to assess the status of vitamin B12 and folate in maternal serum (MS) and umbilical cord serum (UCS). This was a planned secondary analysis of a case-control study. A total of 858 pregnant women during late pregnancy and their newborns in the hospitals of China were included. Maternal peripheral venous blood and neonatal umbilical cord blood were collected to determine serum vitamin B12 and folate concentration. Relationship of vitamin B12 or folate concentration between MS and UCS was assessed by a quantile regression model and the non-linear relationship between them was examined. Nutritional status of serum folate was better than that of vitamin B12. Prevalence of deficiency in MS vitamin B12 and folate was 73.4% and 14.2%, respectively and these figures were about 17.8% and 0.1% in UCS. Both vitamin B12 and folate levels in UCS were significantly higher than those in MS (vitamin B12: 321.0 pg/mL vs 158.3 pg/mL, folate: 16.5 ng/mL vs 7.0 ng/mL, P <0.001). The median UCS-MS ratio of vitamin B12 and folate was 2.0 (95% CI: 1.94-2.06) and 2.4 (95% CI: 2.30-2.53), respectively. The levels of folate and vitamin B12 in UCS increased nonlinearly with their increase in MS which presented an inverted U-shaped curve. Deficiency in vitamin B12 and folate in the women during late pregnancy in China is prevalent. Nutritional status of the two vitamins in umbilical cord serum is correlated nonlinearly with that in maternal serum. Folic acid supplementation may be accompanied with vitamin B12 to improve status of vitamin B12 and folate during pregnancy.

The association between methylmalonic acid, a biomarker of mitochondria dysfunction, and phenotypic age acceleration: A population-based study

Phenotypic age acceleration (PAA) is a sensitive marker of biological aging. Circulating methylmalonic acid (MMA) is a novel biomarker of mitochondrial dysfunction and has been associated with age-related disorders. Our study aimed to investigate to what extent circulating MMA was associated with PAA, and whether the association was independent of vitamin B12 status and renal function in the general population. We analyzed cross-sectional data from 13,023 participants across a wide age range (mean age: 38.9 years, range: 12 – 85 years, 51.1% women) from the US National Health and Nutrition Examination Survey (NHANES). PAA was calculated based on the published algorithm. Linear regression models were performed to assess the association between circulating MAA and PAA. Only 31% of the variation in MMA levels was explained by age, sex, race/ethnicity, social economic status, vitamin B12 status, and renal function. Per unit increase in circulating MAA (1.0 nmol/L) was associated with 1.59 years increase in PAA (β = 1.59, 95% CI: 1.17, 2.00, p < 0.001) after adjusting for multiple confounders. Importantly, PAA increased with circulating MMA levels independent of vitamin B12, creatine, and homocysteine levels. The association was more pronounced in subgroups of age ≥ 65 years, women, underweight, vitamin B12 < 400 μmol/L, and homocysteine ≥ 10 μmol/L. The association was much stronger among participants with cardiovascular diseases (CVDs) than without CVDs. In conclusion, our current population-based study showed that mitochondria-derived circulating MMA was associated with increased phenotypic age acceleration in the general population.