Thiamine deficiency is prevalent in a selected group of urban Indonesian elderly people.
(1/4015)
This cross-sectional study involved 204 elderly individuals (93 males and 111 females). Subjects were randomly recruited using a list on which all 60-75 y-old-people living in seven sub-villages in Jakarta were included. The usual food intake was estimated using semiquantitative food frequency questionnaires. Hemoglobin, plasma retinol, vitamin B-12, red blood cell folate and the percentage stimulation of erythrocyte transketolase (ETK), as an indicator of thiamine status, were analyzed. Median energy intake was below the assessed requirement. More than 75% of the subjects had iron and thiamine intakes of approximately 2/3 of the recommended daily intake, and 20.2% of the study population had folate intake of approximately 2/3 of the recommended daily intake. Intakes of vitamins A and B-12 were adequate. Biochemical assessments demonstrated that 36.6% of the subjects had low thiamine levels (ETK stimulation > 25%). The elderly men tended to have lower thiamine levels than the elderly women. The overall prevalence of anemia was 28.9%, and the elderly women were affected more than the elderly men. Low biochemical status of vitamins A, B-12 and RBC folate was found in 5.4%, 8.8 % and 2.9% of the subjects, respectively. Dietary intakes of thiamine and folate were associated with ETK stimulation and plasma vitamin B-12 concentration (r = 0.176, P = 0.012 and r = 0.77, P = 0.001), respectively. Results of this study suggest that anemia, thiamine and possibly vitamin B-12 deficiency are prevalent in the elderly living in Indonesia. Clearly, micronutrient supplementation may be beneficial for the Indonesian elderly population living in underprivileged areas. (+info)
Plasma total homocysteine and cysteine in relation to glomerular filtration rate in diabetes mellitus.
(2/4015)
BACKGROUND: The plasma concentrations of total homocysteine (tHcy) and total cysteine (tCys) are determined by intracellular metabolism and by renal plasma clearance, and we hypothesized that glomerular filtration is a major determinant of plasma tHcy and tCys. We studied the relationships between the glomerular filtration rate (GFR) and plasma tHcy and tCys in populations of diabetic patients with particularly wide ranges of GFR. METHODS: We measured GFR, urine albumin excretion rate (UAER), plasma tHcy, tCys, methionine, vitamin B12, folate, C-peptide, and routine parameters in 50 insulin-dependent diabetes mellitus (IDDM) and 30 non-insulin-dependent diabetes mellitus (NIDDM) patients. All patients underwent intensive insulin treatment and had a serum creatinine concentration below 115 micromol/liter. RESULTS: Mean plasma tHcy in diabetic patients (0.1 micromol/liter) was lower than in normal persons (11.1 micromol/liter, P = 0.0014). Mean plasma tCys in diabetic patients (266.1 micromol/liter) was also lower than in normal persons (281.9 micromol/liter, P = 0.0005). Seventy-three percent of the diabetic patients had relative hyperfiltration. Plasma tHcy and tCys were closely and independently associated with GFR, serum folate, and serum B12. However, plasma tHcy was not independently associated with any of the 22 other variables tested, including age, serum creatinine concentration, UAER, total daily insulin dose, and glycemic control. CONCLUSIONS: Glomerular filtration rate is an independent determinant of plasma tHcy and tCys concentrations, and GFR is rate limiting for renal clearance of both homocysteine and cysteine in diabetic patients without overt nephropathy. Declining GFR explains the age-related increase in plasma tHcy, and hyperfiltration explains the lower than normal mean plasma tHcy and tCys concentrations in populations of diabetic patients. (+info)
Effect of MTHFR 677C>T on plasma total homocysteine levels in renal graft recipients.
(3/4015)
BACKGROUND: Hyperhomocysteinemia is an established, independent risk factor for vascular disease morbidity and mortality. The 5,10-methylenetetrahydrofolate reductase (MTHFR) gene polymorphism C677T has been shown to result in increased total homocysteine concentrations on the basis of low folate levels caused by a decreased enzyme activity. The effect of this polymorphism on total homocysteine and folate plasma levels in renal transplant patients is unknown. METHODS: We screened 636 kidney graft recipients for the presence of the MTHFR C677T gene polymorphism. The major determinants of total homocysteine and folate plasma concentrations of 63 patients, who were identified to be homozygous for this gene polymorphism compared with heterozygotes (N = 63), and patients with wild-type alleles (N = 63), who were matched for sex, age, glomerular filtration rate (GFR), and body mass index, were identified by analysis of covariance. The variables included sex, age, GFR, body mass index, time since transplantation, folate and vitamin B12 levels, the use of azathioprine, and the MTHFR genotype. To investigate the impact of the kidney donor MTHFR genotype on total homocysteine and folate plasma concentrations, a similar model was applied in 111 kidney graft recipients with stable graft function, in whom the kidney donor C677T MTHFR gene polymorphism was determined. RESULTS: The allele frequency of the C677T polymorphism in the MTHFR gene was 0.313 in the whole study population [wild-type (CC), 301; heterozygous (CT), 272; and homozygous mutant (TT), 63 patients, respectively] and showed no difference in the patient subgroups with various renal diseases. The MTHFR C677T gene polymorphism significantly influenced total homocysteine and folate plasma concentrations in renal transplant recipients (P = 0.0009 and P = 0.0002, respectively). Furthermore, a significant influence of the GFR (P = 0.0001), folate levels (P = 0.0001), age (P = 0.0001), body mass index (P = 0.0001), gender (P = 0.0005), and vitamin B12 levels (P = 0.004) on total homocysteine concentrations was observed. The donor MTHFR gene polymorphism had no influence on total homocysteine and folate levels. Geometric mean total homocysteine levels in patients homozygous for the mutant MTHFR allele were 18.6 micromol/liter compared with 14.6 micromol/liter and 14.9 micromol/liter in patients heterozygous for the MTHFR gene polymorphism and those with wild-type alleles (P < 0.05 for TT vs. CT and CC). Geometric mean folate levels were lower in CT and TT patients (11.2 and 10.2 nmol/liter) compared with CC patients (13.6 nmol/liter, P < 0.05 vs. CT and TT). CONCLUSIONS: This study demonstrates that homozygosity for the C677T polymorphism in the MTHFR gene significantly increases total homocysteine concentrations and lowers folate levels in kidney graft recipients, even in patients with excellent renal function (GFR more than median). These findings have important implications for risk evaluation and vitamin intervention therapy in these patients who carry an increased risk for the development of cardiovascular disease. (+info)
Endothelial dysfunction by acute hyperhomocyst(e)inaemia: restoration by folic acid.
(4/4015)
Recent evidence demonstrates that hyperhomocyst(e)inaemia is a novel risk factor for cardiovascular diseases. In patients with chronic hyperhomocyst(e)inaemia, endothelial function is impaired. However, whether hyperhomocyst(e)inaemia per se is a cause or an epiphenomenon of endothelial dysfunction remains unknown. In this study, we examined the effects of methionine-induced acute hyperhomocyst(e)inaemia on human endothelial function. In healthy volunteers we administered methionine (0.1 g/kg body weight, per os), a substrate of homocyst(e)ine, with or without folic acid (20 mg, per os) and examined flow-mediated vasodilatation of the brachial artery by high-resolution ultrasonography as a non-invasive measure of endothelial function. We also measured plasma levels of homocyst(e)ine before and 3, 8 and 24 h after methionine loading. Methionine administration increased plasma levels of homocyst(e)ine by four times the basal level at 8 h (P<0.0001, ANOVA). The plasma levels returned to baseline at 24 h. Flow-mediated vasodilatation was significantly decreased to half of the baseline value at 8 h and returned to baseline at 24 h (P<0.0001, ANOVA), whereas endothelium-independent vasodilatation by glyceryl trinitrate was not affected by the methionine loading. Co-administration of folic acid did not attenuate methionine-induced hyperhomocyst(e)inaemia but completely prevented endothelial dysfunction. Our results suggest that in humans a methionine-rich diet may acutely impair endothelial function, which can be prevented by folic acid supplementation. (+info)
Influence of haemodialysis on plasma total homocysteine concentration.
(5/4015)
BACKGROUND: The high prevalence of hyperhomocysteinaemia in uraemic patients is of interest because of the cardiovascular risk associated with increased plasma total homocysteine (tHcy) concentration. Treatment with folic acid lowers tHcy in haemodialysis patients, however, in most patients not to normohomocysteinaemic levels. With possible tHcy-lowering modifications in mind, we studied the influence of standard haemodialysis on tHcy. METHODS: In 56 folate-loaded haemodialysis patients, tHcy and parameters of dialysis adequacy were measured. In six patients, interdialytic curves of tHcy and serum creatinine concentrations were obtained and in five patients, the amount of homocysteine (Hcy) in dialysate was determined. RESULTS: tHcy (21.8+/-14.4 micromol/l) correlated significantly with Kt/V (r=0.32, P<0.05), total Kt/V (r=0.29, P<0.05), nPCR (r=0.30, P<0.05) and serum concentrations of albumin (r=0.28, P<0.05) and cobalamines (r=-0.27, P<0.05). In a multiple linear regression analysis, only serum albumin concentrations significantly predicted tHcy (r=0.34, P < 0.05). During dialysis, tHcy decreased by 28% and remained constant for at least 8 h after treatment. The amount of Hcy recovered in dialysate was 63 micromol (12-158 micromol). There was no difference in tHcy between those who had residual renal function and those who had not. CONCLUSIONS: The direct relationship between tHcy and Kt/V seemed to be mediated by the serum albumin concentration. The shape of the interdialytic tHcy curve suggested facilitated Hcy removal for at least 8 h after dialysis possibly due to reduced levels of inhibitory activities against relevant enzyme(s). The dialysed amount of Hcy did not seem to contribute significantly to Hcy removal. Thus, modifications of standard dialytic regimens are not likely to be effective from a tHcy-lowering point of view whereas convective procedures such as haemofiltration or haemodiafiltration might be more effective. (+info)
An estimation of the requirement for folic acid in gestating sows: the metabolic utilization of folates as a criterion of measurement.
(6/4015)
Sows at their second parity were randomly distributed in five groups of seven animals each to determine the dietary concentration of folic acid that optimizes the metabolic utilization of the vitamin during gestation. The groups differed by dietary supplement of folic acid: 0, 5, 10, 15, or 20 ppm. Sows were fed 2.5 kg of diet each day. The response of serum folates and folate binding capacity to treatments and the excretion of urinary folates after an i.v. injection of folic acid were measured. The total daily excretion of urinary folates was corrected according to the response to one i.v. injection of saline on the day preceding the i.v. injection of folic acid. The decrease of total serum folates throughout gestation was less pronounced in the groups fed 15 and 20 ppm of dietary folic acid (supplement x period interaction, P<.06) than it was in the other three treatments. The proportion of i.v. folic acid not recovered in sow urine (injected - excreted) decreased as the amount of dietary folic acid increased to reach a minimum, which differed according to the period (supplement x period interaction, P<.02); it was 15 ppm during wk 1 of gestation and 10 ppm for the other periods studied. The unrecovered folates increased over a dietary concentration of 15 ppm. These minimum values correspond to the most appropriate feed concentration that covered the whole body utilization (tissue and cell metabolism, catabolism, and storage) of folates by the sows and could be interpreted as a reliable index of the requirement. (+info)
MTHFR polymorphism, methyl-replete diets and the risk of colorectal carcinoma and adenoma among U.S. men and women: an example of gene-environment interactions in colorectal tumorigenesis.
(7/4015)
Our studies on interactions of a folate-metabolizing gene polymorphism and dietary intake in colorectal tumorigenesis demonstrate the potential importance of studying interactions between genotype and environmental exposure in relation to cancer risk. We observed an inverse association of a polymorphism (667C --> T, ala --> val) in the methylenetetrahydrofolate reductase (MTHFR) gene with colorectal cancer but not with colorectal adenomas. The inverse association of methionine and adverse association of alcohol with colorectal cancer were stronger among val/val individuals. These interactions were not present in studies of colorectal adenomas. Our studies illustrate that studying gene-environment interactions in relation to cancer can be of importance in clarifying cancer etiology as well as pointing to preventive dietary modifications. (+info)
Hyperhomocyst(e)inaemia in children with chronic renal failure.
(8/4015)
BACKGROUND: Hyperhomocyst(e)inaemia has been identified as a significant risk factor for the occurrence of atherosclerosis in adults with chronic renal failure. Because of its presumed direct toxic effect on the vascular wall, long-standing hyperhomocyst(e)inaemia in children with chronic renal failure might have an important influence on their risk of future development of atherosclerosis. Hitherto no data on hyperhomocyst(e)inaemia in children with renal failure have been published. METHODS: We investigated 16 children with chronic renal failure on conservative management, 12 children on haemodialysis and 17 children with a renal transplant. Age-matched controls were used for comparison. Plasma homocyst(e)ine levels after an overnight fast were determined by HPLC. Glomerular filtration rate was estimated by the Schwartz formula. RESULTS: Mean plasma homocyst(e)ine levels were 12.6 +/- 5.2 micromol/l in the conservatively managed group, 22.2 +/- 13.5 micromol/l in the haemodialysed group, 14.2 +/- 2.1 micromol/l in transplanted children with an estimated GFR > 60 ml/min/1.73 m2 and 17.5 +/- 5.1 micromol/l in transplanted children with a lower estimated GFR. In all groups homocyst(e)ine levels were significantly elevated as compared to controls. Homocyst(e)ine levels were significantly correlated with age and negatively correlated with estimated GFR and serum folate levels. CONCLUSIONS: Hyperhomocyst(e)inaemia is a feature of chronic renal failure in children as well as in adults. Elevated homocyst(e)ine levels can already be demonstrated in children with renal failure before end-stage renal disease has developed and persist after renal transplantation. Whether treatment of hyperhomocyst(e)inaemia in children with renal failure decreases the risk for future atherosclerosis remains to be proven. (+info)