-
1.
A Randomized Pilot Trial to Evaluate the Bioavailability of Natural versus Synthetic Vitamin B Complexes in Healthy Humans and Their Effects on Homocysteine, Oxidative Stress, and Antioxidant Levels.
Lindschinger, M, Tatzber, F, Schimetta, W, Schmid, I, Lindschinger, B, Cvirn, G, Stanger, O, Lamont, E, Wonisch, W
Oxidative medicine and cellular longevity. 2019;:6082613
Abstract
The vitamin B complex comprises 8 different water-soluble constituents that humans must sequester from the diet. This pilot study compared natural versus synthetic vitamin B complexes for their bioavailability, accumulation, and their impact on antioxidants, homocysteine levels, and oxidative stress. We conducted a double-blind randomized clinical trial with thirty healthy participants. They were randomly assigned to group N (natural) and group S (synthetic). Vitamin B was ingested daily for 6 weeks in the range of about 2.5 times above the recommended daily allowance. Blood samples were taken at baseline, 1.5 h, 4 h, 7 h (diurnal), 6 w (discontinuation of supplements), and 8 w (washout). Blood levels of thiamine (B1), riboflavin (B2), pyridoxine (B6), folic acid (B9), cobalamin (B12), homocysteine, total antioxidants, peroxidase activity, polyphenols, and total peroxides were determined. Compared to initial values, serum levels of each B vitamin increased at the end of the supplementation period: i.e., B1 (+23% N; +27% S), B2 (+14% N; +13% S), B6 (+101% N; +101% S), B9 (+86% N; +153% S), and B12 (+16% N) (p < 0.05). Homocysteine (-13% N) decreased, while peroxidase activity (+41% S) and antioxidant capacity increased (+26% N). Short-term effects were already observed after 1.5 h for B9 (+238% N; +246% S) and after 4 h for vitamin B2 (+7% N; +8% S), B6 (+59% N; +51% S), and peroxidase activity (+58% N; +58% S). During the washout period, serum levels of B vitamins decreased except for thiamine and peroxidase activity, which increased further. This clinical pilot study revealed comparable bioavailability for both natural and synthetic B vitamins but did not show statistically noticeable differences between groups despite some favourable tendencies within the natural vitamin group, i.e., sustained effects for cobalamin and endogenous peroxidase activity and a decrease in homocysteine and oxidative stress levels.
-
2.
Effect of long-term low-dose folic acid supplementation on degree of total homocysteine-lowering: major effect modifiers.
Wang, B, Wu, H, Li, Y, Ban, Q, Huang, X, Chen, L, Li, J, Zhang, Y, Cui, Y, He, M, et al
The British journal of nutrition. 2018;(10):1122-1130
Abstract
We sought to examine the potential modifiers in the association between long-term low-dose folic acid supplementation and the reduction of serum total homocysteine (tHcy) among hypertensive patients, using data from the China Stroke Primary Prevention Trial (CSPPT). This analysis included 16 867 participants who had complete data on tHcy measurements at both the baseline and exit visit. After a median treatment period of 4·5 years, folic acid treatment significantly reduced the tHcy levels by 1·6 μmol/l (95 % CI 1·4, 1·8). More importantly, after adjustment for baseline tHcy and other important covariates, a greater degree of tHcy reduction was observed in certain subgroups: males, the methylenetetrahydrofolate reductase (MTHFR) 677TT genotype, higher baseline tHcy levels (≥12·5 (median) v. <12·5 μmol/l), lower folate levels (<8·0 (median) v. ≥8·0 ng/ml), estimated glomerular filtration rate (eGFR) <60 ml/min per 1·73 m2 (v. 60-<90 and ≥90 ml/min per 1·73 m2), ever smokers and concomitant use of diuretics (P for all interactions <0·05). The degree of tHcy reduction associated with long-term folic acid supplementation can be significantly affected by sex, MTHFR C677T genotypes, baseline folate, tHcy, eGFR levels and smoking status.
-
3.
MTHFR 677C → T genotype modulates the effect of a 5-year supplementation with B-vitamins on homocysteine concentration: The SU.FOL.OM3 randomized controlled trial.
Fezeu, LK, Ducros, V, Guéant, JL, Guilland, JC, Andreeva, VA, Hercberg, S, Galan, P
PloS one. 2018;(5):e0193352
Abstract
AIMS: To study how MTHFR 677C→T genotype modulates the effect of supplementation with B-vitamins on total homocysteine (tHcy) and B-vitamin concentrations. METHODS 2381 patients with a personal history of cardiovascular disease were randomly assigned to one of four groups: 1) B-vitamins alone (560 μg of 5-methyl-THF, 3 mg of vitamin B6 and 20 μg of vitamin B12), 2) n-3 fatty acids alone (600 mg of EPA and DHA in a 2:1 ratio), 3) B-vitamins and n-3 fatty acids, and 4) placebo. Participants were followed up for 4.7 years. At baseline and annually thereafter, biological parameters were assessed. Multivariate and linear mixed models were fit to study the interaction between B-vitamins and MTHFR genotype. RESULTS Among supplemented participants, concentrations of all three B-vitamins increased during the first year (all p<0.0001) across MTHFR genotype categories. tHcy decreased by 26.3% during the first year (p<0.0001), then steadily increased throughout the 5 years (ptrend<0.001). However, at the end of follow-up, that increase was smaller among TT than among CT or CC subjects (pinteraction<0.02). At baseline, the difference in tHcy concentrations between TT homozygous and CC homozygous subjects was 2.33 μmol/l (p<0.001). After 5 years, that difference was reduced to 1.06 μmol/l and remained statistically significant (p<0.001). CONCLUSION Participants with the TT genotype exhibited a lower 5-year decrease in tHcy concentrations following a B-vitamin supplementation than did participants with the CC or CT genotype. CLINICAL TRIAL REGISTRATION Current Controlled Trials # ISRCTN41926726.
-
4.
Prospective study of plasma homocysteine, its dietary determinants, and risk of age-related macular degeneration in men.
Christen, WG, Cook, NR, Chiuve, SE, Ridker, PM, Gaziano, JM
Ophthalmic epidemiology. 2018;(1):79-88
-
-
Free full text
-
Abstract
PURPOSE Cross-sectional and case-control studies generally support a direct association between elevated plasma homocysteine and age-related macular degeneration (AMD), but data from prospective studies are limited. We examined the prospective relation of plasma homocysteine level, its dietary determinants, and risk of AMD in a large cohort of apparently healthy male physicians. METHODS During a mean follow-up of 11.2 years, we identified 146 incident cases of visually significant AMD (responsible for a reduction of visual acuity to 20/30 or worse), and 146 controls matched for age, smoking status, and time of blood draw. We measured concentration of homocysteine in blood samples collected at baseline using an enzymatic assay. and we assessed dietary intake of B vitamins and related compounds betaine and choline with a food frequency questionnaire administered at baseline. RESULTS AMD was not associated with plasma level of homocysteine; the multivariable-adjusted odds ratio (OR) of AMD comparing the highest and lowest quartile of homocysteine was 1.09 (95% confidence interval [95% CI]: 0.52-2.31; p for trend = 0.99). However, AMD was inversely associated with quartile of intake of total folate (OR: 0.55; 95% CI: 0.24-1.23; p for trend = 0.08), vitamin B6 from food (OR: 0.39; 95% CI: 0.17-0.88; p for trend = 0.01), and betaine (OR: 0.53; 95% CI: 0.22-1.27; p for trend = 0.048). CONCLUSIONS These prospective data from a cohort of apparently healthy men do not support a major role for homocysteine in AMD occurrence, but do suggest a possible beneficial role for higher intake of several nutrients involved in homocysteine metabolism.
-
5.
Plasma Homocysteine and Prognosis of Acute Ischemic Stroke: a Gender-Specific Analysis From CATIS Randomized Clinical Trial.
Zhong, C, Xu, T, Xu, T, Peng, Y, Wang, A, Wang, J, Peng, H, Li, Q, Geng, D, Zhang, D, et al
Molecular neurobiology. 2017;(3):2022-2030
Abstract
Elevated total homocysteine level (tHcy) has been hypothesized to be associated with morbidity and mortality of stroke; however, results regarding the association between plasma tHcy status and prognosis of acute ischemic stroke are inconsistent. Moreover, the gender effect on this association has yet to be explored. We thus prospectively investigated whether higher tHcy concentrations predicted poor stroke prognosis in Chinese adults. A total of 3309 acute ischemic stroke patients were included in this prospective multicenter study from the China Antihypertensive Trial in Acute Ischemic Stroke (CATIS). Baseline tHcy concentrations were quantitatively determined via enzymatic cycling assay. The primary outcome was a combination of death and major disability at 3 months (modified Rankin scale scores 3-6) after hospitalization. Multivariate logistic regression models with restricted cubic splines were used to determine the association between baseline plasma tHcy and the subsequent outcome. Higher plasma tHcy concentrations were associated with increased risks of the primary outcome in women but not in men (P interaction = 0.016). Adjusted odds ratios comparing two extreme tHcy quartiles were 1.83 (95 % confidence interval 1.12-2.98; P trend = 0.02) in women and 0.87 (95 % confidence interval 0.61-1.25; P trend = 0.37) in men. The significant association between baseline tHcy status and stroke prognosis in women, but not in men, persisted in further subgroup analyses, stratified by age, baseline systolic blood pressure, and other pre-specified factors. Elevated tHcy is positively associated with poor prognosis of acute ischemic stroke in women, but not in men. Further studies are needed to replicate our findings and to clarify the potential sex-specific mechanisms.
-
6.
Effects of Two-Year Vitamin B12 and Folic Acid Supplementation on Depressive Symptoms and Quality of Life in Older Adults with Elevated Homocysteine Concentrations: Additional Results from the B-PROOF Study, an RCT.
de Koning, EJ, van der Zwaluw, NL, van Wijngaarden, JP, Sohl, E, Brouwer-Brolsma, EM, van Marwijk, HW, Enneman, AW, Swart, KM, van Dijk, SC, Ham, AC, et al
Nutrients. 2016;(11)
Abstract
Lowering elevated plasma homocysteine (Hcy) concentrations by supplementing vitamin B12 and folic acid may reduce depressive symptoms and improve health-related quality of life (HR-QoL) in older adults. This study aimed to test this hypothesis in a randomized controlled trial. Participants (N = 2919, ≥65 years, Hcy concentrations ≥12 µmol/L) received either 500 µg vitamin B12 and 400 µg folic acid daily or placebo for two years. Both tablets contained 15 µg vitamin D₃. Depressive symptoms were measured with the Geriatric Depression Scale-15 (GDS-15). HR-QoL was assessed with the SF-12 Mental and Physical component summary scores and the EQ-5D Index score and Visual Analogue Scale. Differences in two-year change scores were analyzed with Analysis of Covariance (ANCOVA). Hcy concentrations decreased more in the intervention group, but two-year change scores of the GDS-15 and three of four HR-QoL measures did not differ between groups. The EQ-5D Index score declined less in the intervention group than in the placebo group (mean change 0.00 vs. -0.02, p = 0.004). In conclusion, two-year supplementation with vitamin B12 and folic acid in older adults with hyperhomocysteinemia showed that lowering Hcy concentrations does not reduce depressive symptoms, but it may have a small positive effect on HR-QoL.
-
7.
Effect of vitamin B12 and folic acid supplementation on biomarkers of endothelial function and inflammation among elderly individuals with hyperhomocysteinemia.
van Dijk, SC, Enneman, AW, Swart, KM, van Wijngaarden, JP, Ham, AC, de Jonge, R, Blom, HJ, Feskens, EJ, Geleijnse, JM, van Schoor, NM, et al
Vascular medicine (London, England). 2016;(2):91-8
Abstract
B-vitamin trials failed to demonstrate beneficial effects on cardiovascular outcomes, but hyperhomocysteinemia still stands out as an independent cardiovascular risk factor, particularly in elderly individuals. B-vitamins may influence early vascular dysfunction, such as endothelial dysfunction, or may have adverse effects, for example on inflammation. We investigated the effect of B-vitamins on endothelial function and inflammation within an interventional study. This study was conducted within the framework of the B-PROOF trial, which included 2919 hyperhomocysteinemic elderly individuals, who received daily vitamin B12 (500 μg) and folic acid (400 μg) or placebo for 2 years. Using an electrochemiluminescence platform, we measured intercellular adhesion molecule 1 (ICAM-1), vascular adhesion molecule 1 (VCAM-1), serum amyloid A (SAA), vascular endothelial growth factor (VEGF) and C-reactive protein (CRP) at baseline and follow-up in a subsample of 522 participants (271 intervention group; 251 placebo). Treatment effects were analyzed with ANCOVA. The participants had a mean age of 72 years, and 55% of them were male. At the 2-year follow-up, B-vitamins did not change the ICAM-1 (+36% change in the intervention group versus +32% change in the placebo group; p = 0.72), VCAM-1 (+27% vs +25%; p = 0.39), VEGF (-1% vs +4%; p = 0.40), SAA (+34% vs +38%; p = 0.85) or CRP levels (+26% vs +36%; p = 0.70) as compared to placebo. In conclusion, in elderly patients with hyperhomocysteinemia, vitamin B12 and folic acid are unlikely to influence either endothelial function or low-grade systemic inflammation. ClinicalTrials.gov Identifier: NCT00696514.
-
8.
Effect of Vitamin B12 and Folic Acid Supplementation on Bone Mineral Density and Quantitative Ultrasound Parameters in Older People with an Elevated Plasma Homocysteine Level: B-PROOF, a Randomized Controlled Trial.
Enneman, AW, Swart, KM, van Wijngaarden, JP, van Dijk, SC, Ham, AC, Brouwer-Brolsma, EM, van der Zwaluw, NL, Dhonukshe-Rutten, RA, van der Cammen, TJ, de Groot, LC, et al
Calcified tissue international. 2015;(5):401-9
-
-
Free full text
-
Abstract
High plasma homocysteine (Hcy) levels are associated with increased osteoporotic fracture incidence. However, the mechanism remains unclear. We investigated the effect of Hcy-lowering vitamin B12 and folic acid treatment on bone mineral density (BMD) and calcaneal quantitative ultrasound (QUS) parameters. This randomized, double-blind, placebo-controlled trial included participants aged ≥65 years with plasma Hcy levels between 12 and 50 µmol/L. The intervention comprised 2-year supplementation with either a combination of 500 µg B12, 400 µg folic acid, and 600 IU vitamin D or placebo with 600 IU vitamin D only. In total, 1111 participants underwent repeated dual-energy X-ray assessment and 1165 participants underwent QUS. Femoral neck (FN) BMD, lumbar spine (LS) BMD, calcaneal broadband ultrasound attenuation (BUA), and calcaneal speed of sound (SOS) were assessed. After 2 years, FN-BMD and BUA had significantly decreased, while LS-BMD significantly increased (all p < 0.01) and SOS did not change in either treatment arm. No statistically significant differences between the intervention and placebo group were present for FN-BMD (p = 0.24), LS-BMD (p = 0.16), SOS (p = 0.67), and BUA (p = 0.96). However, exploratory subgroup analyses revealed a small positive effect of the intervention on BUA at follow-up among compliant persons >80 years (estimated marginal mean 64.4 dB/MHz for the intervention group and 61.0 dB/MHz for the placebo group, p = 0.04 for difference). In conclusion, this study showed no overall effect of treatment with vitamin B12 and folic acid on BMD or QUS parameters in elderly, mildly hyperhomocysteinemic persons, but suggests a small beneficial effect on BUA in persons >80 years who were compliant in taking the supplement.
-
9.
Plasma homoarginine, arginine, asymmetric dimethylarginine and total homocysteine interrelationships in rheumatoid arthritis, coronary artery disease and peripheral artery occlusion disease.
Kayacelebi, AA, Willers, J, Pham, VV, Hahn, A, Schneider, JY, Rothmann, S, Frölich, JC, Tsikas, D
Amino acids. 2015;(9):1885-91
Abstract
Elevated circulating concentrations of total L-homocysteine (thCys) and free asymmetric dimethylarginine (ADMA) are long-established cardiovascular risk factors. Low circulating L-homoarginine (hArg) concentrations were recently found to be associated with increased cardiovascular morbidity and mortality. The biochemical pathways of these amino acids overlap and share the same cofactor S-adenosylmethionine (SAM). In the present study, we investigated potential associations between hArg, L-arginine (Arg), ADMA and thCys in plasma of patients suffering from rheumatoid arthritis (RA), coronary artery disease (CAD) or peripheral artery occlusive disease (PAOD). In RA, we did not find any correlation between ADMA or hArg and thCys at baseline (n = 100) and after (n = 83) combined add-on supplementation of omega-3 fatty acids, vitamin E, vitamin A, copper, and selenium, or placebo (soy oil). ADMA correlated with Arg at baseline (r = 0.446, P < 0.001) and after treatment (r = 0.246, P = 0.03). hArg did not correlate with ADMA, but correlated with Arg before (r = 0.240, P = 0.02) and after treatment (r = 0.233, P = 0.03). These results suggest that hArg, ADMA and Arg are biochemically familiar with each other, but unrelated to hCys in RA. In PAOD and CAD, ADMA and thCys did not correlate.
-
10.
Homocysteine, an additional factor, is linked to osteoporosis in postmenopausal women with type 2 diabetes.
Jianbo, L, Zhang, H, Yan, L, Xie, M, Mei, Y, Jiawei, C
Journal of bone and mineral metabolism. 2014;(6):718-24
Abstract
We explored the relationship between plasma total homocysteine concentration and osteoporosis in postmenopausal patients with type 2 diabetes. Postmenopausal patients with type 2 diabetes (n = 258) were enrolled in a cross-sectional hospital-based study. Osteoporosis was documented by dual energy X-ray absorptiometry. Plasma total homocysteine concentration was measured using fluorescence polarization immunoassay. Risk factors for osteoporosis and determinants of homocysteine were obtained from blood samples and interviewer questionnaire. We found that plasma total homocysteine levels were higher in subjects with osteoporosis and diabetes than without [(9.5 ± 2.0) vs. (10.4 ± 2.4) μmol/l, p = 0.001]. The association of homocysteine with osteoporosis was independent of possible risk factors for osteoporosis in diabetes (e.g., duration of diabetes, HbA1c, body mass index, serum 25-hydroxyvitamin D, thiazolidinediones, and retinopathy) and determinants of homocysteine concentration (age, serum folate and vitamin B12, renal status, and biguanide use) [OR 1.40 (1.02-1.90), p = 0.036]. In addition, bone mineral density was closely correlated with homocysteine as a continuous variable after adjusting for age [r = -0.64 (-0.69 to -0.58), p = 0.002]. Furthermore, per increase of 5.0 μmol/l, plasma homocysteine was related to osteoporosis, after controlling for per unit increase of other factors [OR 1.42 (1.07-1.96), p = 0.027]. The optimal cut-off point for the plasma homocysteine level distinguishing diabetic patients with osteoporosis from without was 10.18 μmol/l. The results suggest that plasma total homocysteine concentration is independently associated with the occurrence of osteoporosis in postmenopausal patients with type 2 diabetes. Future prospective studies are warranted to clarify the relationship.