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1.
Vitamin B6 in Health and Disease.
Stach, K, Stach, W, Augoff, K
Nutrients. 2021;(9)
Abstract
Vitamin B6 is a fascinating molecule involved in the vast majority of changes in the human body because it is a coenzyme involved in over 150 biochemical reactions. It is active in the metabolism of carbohydrates, lipids, amino acids, and nucleic acids, and participates in cellular signaling. It is an antioxidant and a compound with the ability to lower the advanced glycation end products (AGE) level. In this review, we briefly summarize its involvement in biochemical pathways and consider whether its deficiency may be associated with various diseases such as diabetes, heart disease, cancer, or the prognosis of COVID-19.
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2.
Revised D-A-CH Reference Values for the Intake of Vitamin B6.
Jungert, A, Linseisen, J, Wagner, KH, Richter, M, ,
Annals of nutrition & metabolism. 2020;(4):213-222
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Abstract
BACKGROUND The Nutrition Societies of Germany, Austria, and Switzerland as the joint editors of the "D-A-CH reference values for nutrient intake" have revised the reference values for vitamin B6 in summer 2019. SUMMARY For women, the average requirement (AR) for vitamin B6 intake was derived on the basis of balance studies using a pyridoxal-5'-phosphate (PLP) plasma concentration of ≥30 nmol/L as a biomarker of an adequate vitamin B6 status. The recommended intake (RI) was derived considering a coefficient of variation of 10%. The RIs of vitamin B6 for men, children, and adolescents were extrapolated from the vitamin B6 requirement for women considering differences in body weight, an allometric exponent, growth factors as appropriate, and a coefficient of variation. For infants aged 0 to under 4 months, an estimated value was set based on the vitamin B6 intake via breast feeding. The reference value for infants aged 4 to under 12 months was extrapolated from the estimated value for infants under 4 months of age and the average vitamin B6 requirement for adults. The reference values for pregnant and lactating women consider the requirements for the foetus and the loss via breast milk. Key Messages: According to the combined analysis of 5 balance studies, the AR for vitamin B6 to ensure a plasma PLP concentration of ≥30 nmol/L is 1.2 mg/day for adult females and the extrapolated AR for adult males is 1.3 mg/day. The corresponding RIs of vitamin B6 are 1.4 mg/day for adult females and 1.6 mg/day for adult males, independent of age. For infants, the estimated value is 0.1 mg/day and 0.3 mg/day, depending on age. The AR of vitamin B6 for children and adolescents ranges between 0.5 and 1.5 mg/day, and the RI is between 0.6 mg/day and 1.6 mg/day. During pregnancy, the AR is 1.3 mg/day in the first trimester and 1.5 mg/day in the second and third trimesters; the RI is 1.5 mg/day in the first trimester and 1.8 mg/day in the second and third trimesters. For lactating women, the AR is 1.3 mg/day and the RI is 1.6 mg/day.
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Acne related to dietary supplements.
Zamil, DH, Perez-Sanchez, A, Katta, R
Dermatology online journal. 2020;(8)
Abstract
Multiple prescription medications may cause or aggravate acne. A number of dietary supplements have also been linked to acne, including those containing vitamins B6/B12, iodine, and whey, as well as "muscle building supplements" that may be contaminated with anabolic-androgenic steroids (AAS). Acne linked to dietary supplements generally resolves following supplement discontinuation. Lesions associated with high-dose vitamin B6 and B12 supplements have been described as monomorphic and although pathogenesis is unknown, a number of hypotheses have been proposed. Iodine-related acne may be related to the use of kelp supplements and has been reported as monomorphic, inflammatory pustules on the face and upper trunk. Whey protein supplements, derived from milk and used for bodybuilding, are associated with papulonodular acne involving the trunk and sometimes the face. Finally, AAS-induced acne has been described as acne fulminans, acne conglobata, and acne papulopustulosa. With studies indicating that about half of US adults report using dietary supplements, it is important that dermatologists directly ask acne patients about their supplement use and educate them on the potential risks of even seemingly innocuous dietary supplements.
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Vitamin B Supplementation and Nutritional Intake of Methyl Donors in Patients with Chronic Kidney Disease: A Critical Review of the Impact on Epigenetic Machinery.
Cappuccilli, M, Bergamini, C, Giacomelli, FA, Cianciolo, G, Donati, G, Conte, D, Natali, T, La Manna, G, Capelli, I
Nutrients. 2020;(5)
Abstract
Cardiovascular morbidity and mortality are several-fold higher in patients with advanced chronic kidney disease (CKD) and end-stage renal disease (ESRD) than in the general population. Hyperhomocysteinemia has undoubtedly a central role in such a prominent cardiovascular burden. The levels of homocysteine are regulated by methyl donors (folate, methionine, choline, betaine), and cofactors (vitamin B6, vitamin B12,). Uremia-induced hyperhomocysteinemia has as its main targets DNA methyltransferases, and this leads to an altered epigenetic control of genes regulated through methylation. In renal patients, the epigenetic landscape is strictly correlated with the uremic phenotype and dependent on dietary intake of micronutrients, inflammation, gut microbiome, inflammatory status, oxidative stress, and lifestyle habits. All these factors are key contributors in methylome maintenance and in the modulation of gene transcription through DNA hypo- or hypermethylation in CKD. This is an overview of the epigenetic changes related to DNA methylation in patients with advanced CKD and ESRD. We explored the currently available data on the molecular dysregulations resulting from altered gene expression in uremia. Special attention was paid to the efficacy of B-vitamins supplementation and dietary intake of methyl donors on homocysteine lowering and cardiovascular protection.
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Associations between B Vitamins and Parkinson's Disease.
Shen, L
Nutrients. 2015;(9):7197-208
Abstract
B vitamins may correlate with Parkinson's disease (PD) through regulating homocysteine level. However, there is no comprehensive assessment on the associations between PD and B vitamins. The present study was designed to perform a meta-analytic assessment of the associations between folate, vitamin B6, and vitamin B12 and PD, including the status of B vitamins in PD patients compared with controls, and associations of dietary intakes of B vitamins and risk of PD. A literature search using Medline database obtained 10 eligible studies included in the meta-analyses. Stata 12.0 statistical software was used to perform the meta-analysis. Pooled data revealed that there was no obvious difference in folate level between PD patients and healthy controls, and PD patients had lower level of vitamin B12 than controls. Available data suggested that higher dietary intake of vitamin B6 was associated with a decreased risk of PD (odds ratio (OR) = 0.65, 95% confidence intervals (CI) = (0.30, 1.01)), while no significant association was observed for dietary intake of folate and vitamin B12 and risk of PD. PD patients had lower level of vitamin B12 and similar level of folate compared with controls. Dietary intake of vitamin B6 exhibited preventive effect of developing PD based on the available data. As the number of included studies is limited, more studies are needed to confirm the findings and elucidate the underpinning underlying these associations.
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Effect of folic acid, vitamin B6 and vitamin B12 supplementation on mortality and cardiovascular complication among patients with chronic kidney disease: an evidence-based case report.
Nursalim, A, Siregar, P, Widyahening, IS
Acta medica Indonesiana. 2013;(2):150-6
Abstract
AIM: to determine whether the administration of folic acid, vitamin B6 and vitamin B12 would lead to reduction of cardiovascular complication and mortality among CKD patients. METHODS a search was conducted on PubMed and Google. The selection of title and abstract was conducted using inclusion and exclusion criterias, which led to six relevant articles. The selected studies were critically appraised for its validity, importance and applicability. RESULTS the administration of folic acid and vitamin B reduce homocysteine level among CKD patients. Despite homocysteine level reduction, all six studies reported similar findings that folic acid and vitamin B supplementation did not significantly reduce cardiovascular complication and mortality. CONCLUSION treatment with folic acid, vitamin B6 and vitamin B12 did not reduce cardiovascular complication and mortality among CKD patients.
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Pyridoxine for prevention of hand-foot syndrome caused by chemotherapy: a systematic review.
Chen, M, Zhang, L, Wang, Q, Shen, J
PloS one. 2013;(8):e72245
Abstract
BACKGROUND Hand-foot syndrome (HFS) is a relatively frequent dermatologic toxic reaction to certain anti-cancer chemotherapies. The syndrome can evolve into a distressing condition that limits function and affects quality of life. Pyridoxine (vitamin B6) has been used empirically for the prevention of HFS caused by anti-cancer therapy. However, evidence of its efficacy remains controversial. METHODOLOGY//PRINCIPAL FINDINGS Systematic literature searches were conducted on the Cochrane Library, PUBMED, EMBASE, LILACS, CBM, CNKI, VIP, WANFANG and the U.S. ClinicalTrials.gov website. We included all related randomized controlled trials (RCTs) irrespective of language. Reviewers from different professions independently assessed all potential studies and extracted data. Subgroup analysis was planned according to dose of pyridoxine. 5 RCTs involving 607 patients were contributed to the meta-analysis. No significant differences were found between patients receiving pyridoxine and placebo for prevention of incidence of HFS and grade 2 or worse HFS (relative risk (RR) 0.96, 95%confidence interval (CI) 0.86-1.06; RR0.95, 95%CI 0.73-1.24, respectively). Similarly, no significant improvement in quality of life was detected among patients. However, significant difference was found for prevention of grade 2 or worse HFS with pyridoxine 400 mg daily compared to 200 mg (RR0.55, 95%CI 0.33-0.92). CONCLUSIONS/SIGNIFICANCE There is inadequate evidence to make any recommendation about using pyridoxine for prevention of HFS caused by chemotherapy. However, pyridoxine 400 mg may have some efficacy. Further studies of large sample sizes are needed to evaluate the efficacy and safety of pyridoxine, especially at high dose, in comparison with placebo.
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Vitamin B6 and colorectal cancer: current evidence and future directions.
Zhang, XH, Ma, J, Smith-Warner, SA, Lee, JE, Giovannucci, E
World journal of gastroenterology. 2013;(7):1005-10
Abstract
Colorectal cancer remains the third most common cancer in both women and men worldwide. Identifying modifiable dietary factors is crucial in developing primary prevention strategies. Vitamin B6 is involved in more than 100 coenzyme reactions, and may influence colorectal cancer risk in multiple ways including through its role in one-carbon metabolism related DNA synthesis and methylation and by reducing inflammation, cell proliferation, and oxidative stress. Observational studies of dietary or dietary plus supplementary intake of vitamin B6 and colorectal cancer risk have been inconsistent with most studies reporting nonsignificant positive or inverse associations. However, published studies of plasma pyridoxal 5'-phosphate (the active form of vitamin B6) levels consistently support an approximately 30%-50% reduction in risk of colorectal cancer comparing high with low concentrations. The reasons for the discrepancy in the results between dietary-based and plasma-based studies remain unresolved. Other unresolved questions include the effects of vitamin B6 intake in early life (i.e., childhood or adolescence) and of suboptimal vitamin B6 status on colorectal cancer risk, whether the associations with vitamin B6 differ across molecular subtypes of colorectal cancer, and whether the vitamin B6-colorectal cancer association is modified by genetic variants of one-carbon metabolism.
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9.
Mechanisms and structures of vitamin B(6)-dependent enzymes involved in deoxy sugar biosynthesis.
Romo, AJ, Liu, HW
Biochimica et biophysica acta. 2011;(11):1534-47
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Abstract
PLP is well-regarded for its role as a coenzyme in a number of diverse enzymatic reactions. Transamination, deoxygenation, and aldol reactions mediated by PLP-dependent enzymes enliven and enrich deoxy sugar biosynthesis, endowing these compounds with unique structures and contributing to their roles as determinants of biological activity in many natural products. The importance of deoxy aminosugars in natural product biosynthesis has spurred several recent structural investigations of sugar aminotransferases. The structure of a PMP-dependent enzyme catalyzing the C-3 deoxygenation reaction in the biosynthesis of ascarylose was also determined. These studies, and the crystal structures they have provided, offer a wealth of new insights regarding the enzymology of PLP/PMP-dependent enzymes in deoxy sugar biosynthesis. In this review, we consider these recent achievements in the structural biology of deoxy sugar biosynthetic enzymes and the important implications they hold for understanding enzyme catalysis and natural product biosynthesis in general. This article is part of a Special Issue entitled: Pyridoxal Phosphate Enzymology.
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A case of McArdle disease: efficacy of vitamin B6 on fatigability and impaired glycogenolysis.
Izumi, R, Suzuki, N, Kato, K, Warita, H, Tateyama, M, Nakashima, I, Itoyama, Y
Internal medicine (Tokyo, Japan). 2010;(15):1623-5
Abstract
McArdle disease is a glycogenetic myopathy caused by a deficit of myophosphorylase inherited in an autosomal recessive pattern. Here, we report a case of McArdle disease in which fatigability was the only subjective complaint. Objective neurological findings were normal except for very mild muscle weakness in limbs and an elevated serum creatine kinase level. Ischemic forearm exercise test showed deficient glycogenolysis. In the muscle biopsy specimen, periodic acid Schiff (PAS) stained subsarcolemmal glycogen was increased and the muscle phosphorylase A activity was decreased. After administration of vitamin B6, fatigability was diminished and ischemic forearm exercise test showed improved glycogenolysis. Vitamin B6 may be beneficial for McArdle disease, especially for its easy fatigability.