The multiple vitamin status of Chinese pregnant women with anemia and nonanemia in the last trimester

Iron-deficiency or anemia in pregnancy is a major public health problem in China. This cross-sectional study was carried out to observe the association between iron status and multiple vitamin levels of Chinese pregnant women in the third trimester. We measured iron, ascorbic acid, retinol, folate and vitamin B12 in serum, and riboflavin in urine specimens of 1,163 pregnant women in four sites throughout rural and city areas in China. Based on hemoglobin concentrations (Hb), the subjects were divided into an anemia group with Hb < 110 g/L or Hb < or = 100 g/L as severe anemia group, and nonanemia group with Hb > or = 110 g/L. Results showed that 41.58% of the population with serum iron < 700 microg/L and 51.04% of the population with ferritin < 12 microg/L in the anemia group, percentages that were much higher than those in the nonanemia group. Relationships between five vitamins and hemoglobin concentrations of all subjects were observed. There was a lower level of serum ascorbic acid (291.05 microg/dL) in the Hb < or = 100 g/L group than in the Hb > or = 120 g/L group (487.79 microg/dL) (p < 0.001). Serum levels of vitamin B12 and folate were 445.67 pg/mL and 5.94 ng/mL in the Hb < or = 100 g/L group, whose levels were much lower than the levels of 502.01 pg/mL (p < 0.012) and 8.07 ng/mL (p < 0.010) respectively in the Hb > or = 120 g/L group. Further, cross-sectional analysis showed positive correlations between abnormal hematological results and prevalences of vitamin deficiencies. The subjects with iron-deficiency anemia had much higher rates of vitamin C, folate and vitamin B12 deficiencies than those in the nonanemic subjects, and especially in the deficient rates of ascorbic acid and folate in the anemia (Hb < 110 g/L) group, which reached 64.04% and 22.70% respectively. Moreover, we observed that the decreasing trends of hemoglobin concentrations were accompanied by the decreases of serum levels of vitamin A, ascorbic acid, folate and vitamin B12. In conclusion, multiple vitamin deficiencies, especially ascorbic acid, retinol and folic acid, may be associated with anemia or iron deficiency in pregnant women in the last trimester. The study suggested that anemic pregnant women in China should be supplemented with iron and multiple vitamins simultaneously.

Phenotypic expression of the methylenetetrahydrofolate reductase 677C-->T polymorphism and flavin cofactor availability in thyroid dysfunction

BACKGROUND

The 5,10-methylenetetrahydrofolate reductase gene (MTHFR) 677C-->T polymorphism modifies the risk of coronary artery disease and colon cancer and is related to plasma concentrations of total homocysteine (tHcy). Riboflavin status modifies the metabolic effect of the polymorphism, and thyroid hormones increase the synthesis of flavin cofactors.

OBJECTIVE

The aim of the study was to investigate the phenotypic expression of the MTHFR 677C-->T polymorphism in terms of plasma tHcy concentrations in patients with thyroid dysfunction.

DESIGN

The study population consisted of 182 patients with hyperthyroidism. We studied plasma tHcy in relation to MTHFR genotype, riboflavin, and folate before and during 6 mo of treatment with antithyroid drugs.

RESULTS

Before treatment, tHcy was higher in patients with the mutant enzyme than in those with the wild-type enzyme. A genotype effect was observed only at low riboflavin or folate concentrations (P </= 0.05). During treatment, concentrations of flavin cofactors in plasma decreased (P < 0.001), and tHcy increased (P < 0.001). The overall tHcy increase was greatest in patients with the T allele, particularly at low riboflavin concentrations (P = 0.004).

CONCLUSION

Thyroid status affects the phenotypic expression of the MTHFR 677C-->T polymorphism, possibly by modifying the availability of flavin cofactors.

Folate deficiency induces aneuploidy in human lymphocytes in vitro-evidence using cytokinesis-blocked cells and probes specific for chromosomes 17 and 21

Folate plays a critical role in the prevention of chromosome breakage and hypomethylation of DNA. Deficiency in this vitamin may lead to demethylation of heterochromatin causing structural centromere defects that could induce abnormal distribution of replicated chromosomes during nuclear division. Because aneuploidy of chromosomes 17 and 21 is often observed in breast cancer and leukaemia and increased risk for these cancers is associated with folate deficiency, we hypothesized that folate deficiency may lead to aneuploidy of chromosomes 17 and 21. To test these hypotheses we cultured lymphocytes from eight female volunteers (aged 40-48 years) in RPMI 1640 medium containing 12 or 120nM of folic acid (FA) or 5-methyltetrahydrofolate (MF) for 9 days. Chromosomes 17 and 21 aneuploidies induced by folate deficiency were measured in mononucleated (MONO) and cytokinesis-blocked binucleated (BN) lymphocytes after dual-color fluorescent in situ hybridization (FISH) with a digoxigenin-labeled probe for the alphoid satellite sequence of chromosome 17 and a biotin-labeled probe for the pericentric region of chromosome 21. The results showed that 12nm of MF or FA caused a significant 26-35% increment in frequency of aneuploidy of chromosome 17 (P = 0.0017) and aneupoidy of chromosome 21 (P = 0.0008) relative to 120nM MF or FA. The pattern of aneuploidy in binucleated cells was significantly correlated with that observed in mononucleated cells (R = 0.51-0.75, P < 0.0004) and was consistent with a model based on chromosome loss or partial aneusomy rescue as the cause rather than non-disjunction, although the latter mechanism could not be excluded. MF was not more efficient than FA in preventing aneuploidy in this in vitro system. We conclude that folate deficiency is a risk factor for chromosomes 17 and 21 aneuploidy.

Riboflavin deficiency induces ocular surface damage

PURPOSE

To examine the conjunctiva and cornea of riboflavin-deficient rats with scanning (SEM) and transmission (TEM) electron microscopes.

MATERIALS AND METHODS

Three-week-old Wistar Kyoto rats were fed a riboflavin-deficient diet (0.05 mg riboflavin/100 g) for 3 months. As a recovery experiment, rats which had been on a riboflavin-deficient diet for 3 months were given water with 1 mg riboflavin/300 ml for 2 months. The conjunctiva and the cornea were examined with SEM and TEM.

RESULTS

The serum riboflavin level was significantly lower in the riboflavin-deficient group than in the controls. In rats on a riboflavin-deficient diet for 3 months, SEM showed decreased microvilli and microplicae in the superficial epithelium of the conjunctiva and a decrease in the number of goblet cells. The cornea showed many dark cells and a marked decrease of microvilli and microplicae. In the riboflavin-deficient rats, TEM of the conjunctiva showed a decrease of microvilli and microplicae in the most superficial epithelial cells, a decrease in the layers of the epithelium and a marked decrease in the number of goblet cells, while the cornea had decreased microvilli and microplicae in the superficial epithelium, dark wing cells, loss of the basement membrane and hemidesmosomes of basal cells, cell debris and degenerative stroma cells and deposits of dense bodies in the subepithelial layer of the stroma. In rats recovered from riboflavin deficiency, the conjunctiva and cornea showed no abnormalities.

DISCUSSION

Riboflavin plays a role in the development and maintenance of the surface structures of epithelial cells. Riboflavin may also be necessary for the development and maintenance of goblet cells.

CONCLUSION

Riboflavin is essential for maintaining the structure and function of the ocular surface.

A modified vitamin regimen for vitamin B2, A, and E administration in very-low-birth-weight infants

INTRODUCTION

Very-low-birth-weight (VLBW; birth weight, <1,500 g) infants receive preterm infant formulas and parenteral multivitamin preparations that provide more riboflavin (vitamin B2) than does human milk and more than that recommended by the American Society of Clinical Nutrition. VLBW infants who are not breast-fed may have plasma riboflavin concentrations up to 50 times higher than those in cord blood. The authors examined a vitamin regimen designed to reduce daily riboflavin intake, with the hypothesis that this new regimen would result in lower plasma riboflavin concentrations while maintaining lipid-soluble vitamin levels.

METHODS

Preterm infants with birth weight < or =1,000 g received either standard preterm infant nutrition providing 0.42 to 0.75 mg riboflavin/kg/day (standard group), or a modified regimen providing 0.19 to 0.35 mg/kg/day (modified group). The modified group parenteral vitamin infusion was premixed in Intralipid. Enteral feedings were selected to meet daily riboflavin administration guidelines. Plasma riboflavin, vitamin A, and vitamin E concentrations were measured weekly by high-performance liquid chromatography. Data were analyzed with the independent t test, chi, and analysis of variance.

RESULTS

The 36 infants (17 standard group, 19 modified group) had birth weight and gestational age of 779 +/- 29 g and 25.5 +/- 0.3 weeks (mean +/- SEM) with no differences between groups. Modified group infants received 38% less riboflavin (0.281 +/- 0.009 mg/kg/day), 35% more vitamin A (318.3 +/- 11.4 microg/kg/day), and 14% more vitamin E (3.17 +/- 0.14 mg/kg/day) than standard group infants. Plasma riboflavin rose from baseline in both groups but was 37% lower in the modified group during the first postnatal month (133.3 +/- 9.9 ng/mL). Riboflavin intake and plasma riboflavin concentrations were directly correlated. Plasma vitamin A (0.222 +/- 0.022 microg/mL) and vitamin E (22.26 +/- 1.61 /mL) concentrations were greater in the modified group.

CONCLUSIONS

The modified vitamin regimen resulted in reduced riboflavin intake and plasma riboflavin concentration, suggesting plasma riboflavin concentration is partially dose dependent during the first postnatal month in VLBW infants. Modified group plasma vitamin A and vitamin E concentrations were greater during the first month, possibly because the vitamins were premixed with parenteral lipid emulsion. Because of the complexity of this protocol, the authors suggest that a parenteral multivitamin product designed for VLBW infants which uses weight-based dosing should be developed.

[The connection between vitamin and iron status indexes of school-age children]

The analysis of vitamin and iron indexes of 95 children sufficiently supplied with vitamin C and vitamin B2 and carotenoids deficiency has been carried out. Vitamin E deficit takes place among anemic children (with decreased hemoglobin blood level) 2 fold more often than among healthy children. From another side, decreased hemoglobin blood level, erythrocyte quantity and erythrocyte indexes have been determined 1.7-2.4 fold more often in insufficiently supplied with vitamin E children. Tocopherols serum level had tendency to the decrease and vitamin E deficit took place 2 fold more frequently in children suffering from iron deficiency anemia that is with decreased hemoglobin and serum ferritin concentrations. Marked positive linear correlation between these iron indexes and vitamin E serum level has been revealed. These results give evidence concerning significant role of this vitamin in the body iron supplying. The results obtained give evidence for multi-deficient anemia presence among children, which are not always caused by iron deficit. High frequency of vitamin E and B group vitamins deficiency proves expediency of these vitamins inclusion in complex therapy of iron deficiency.

Effects of the interaction between the C677T 5,10-methylenetetrahydrofolate reductase polymorphism and serum B vitamins on homocysteine levels in pregnant women

OBJECTIVE

The purpose of this study was to investigate the effect of the interaction between the C677T mutation in the 5,10-methylenetetrahydrofolate reductase (MTHFR) genotypes and serum levels of B vitamins on serum homocysteine levels in pregnant women.

DESIGN

A cross-sectional study.

SETTING

Ewha Womans University Hospital, Seoul, Korea.

SUBJECTS

A total of 177 normal pregnant women, 24.6+/-1.1 weeks of gestation, in a 6-month period during 2001-2002.

INTERVENTIONS

Serum vitamin B2, vitamin B6, and homocysteine analyses were conducted using high-performance liquid chromatography methods. Serum folate and vitamin B12 concentrations were determined using a radioimmunoassay kit. MTHFR gene mutation was investigated by the polymerase chain reaction of a genomic DNA fragment.

RESULTS

Serum homocysteine was higher in women with the T/T genotype than those with the C/T or C/C genotype of the MTHFR gene (P<0.05). Serum homocysteine was negatively correlated with serum folate in all MTHFR genotypes (P<0.001), and the correlation between the two serum levels was the strongest in the T/T genotype. Serum homocysteine was higher in the subjects with the T/T MTHFR genotype only when the serum folate was below the median level. Explanatory power of B vitamin status as predictors of serum homocysteine levels was more pronounced in the T/T genotypes (68.5%) compared with the C/T (37.9%) or C/C genotypes (20.6%).

CONCLUSIONS

Serum homocysteine levels in pregnant women varied significantly with MTHFR genotype and the serum B vitamin status. Higher serum folate, vitamin B2, and vitamin B12 concentrations may lessen the MTHFR genotypic effect on serum homocysteine levels.

[Nested case-control study on riboflavin levels in blood and urine and the risk of lung cancer]

The present study is designed to explore the relationship between the riboflavin levels in blood and urine and the risk of lung cancer among miners in Yunnan Tin Corporation(YTC) by means of nested case-control design. Cases were patients with lung cancer newly diagnosed from 1992 to 1995. For each case, 2 controls were randomly matched with occupational exposure history, age, the time of collecting blood or urine samples. The indexes for evaluating the riboflavin nutritional status were erythrocyte glutathione reductase activation coefficient (EGR-AC) and the ratio of riboflavin and creatinine in urine. When analyzed as either the continuous or the rank variables, the odds ratios(ORs) used to estimate the relative risk of lung cancer have no statistical significance(P > 0.05) after adjusting the confusing factors. No association of riboflavin indexes in blood and urine with the lung cancer risk among YTC miners were observed in the present study.

Homocysteine and its relation to B-vitamins in Graves' disease before and after treatment: effect modification by smoking

OBJECTIVES

To investigate plasma total homocysteine levels and its relation to B-vitamins and smoking in Graves' disease before and after antithyroid therapy.

DESIGN

A longitudinal study taking place at four hospitals in Norway.

METHODS AND SUBJECTS

Plasma total homocysteine, serum folate, serum cobalamin and riboflavin, flavin mononucleotide and flavin adenine dinucleotide in plasma were investigated in 182 patients with hyperthyroidism before treatment. The same parameters were reinvestigated in 112 of these patients after attaining euthyroid state.

RESULTS

In hyperthyroidism, plasma total homocysteine was low, and inversely related to folate, cobalamin and riboflavin, and positively related to serum creatinine and age. Following antithyroid therapy, total homocysteine increased and the concentration of folate, cobalamin, riboflavin, flavin mononucleotide and flavin adenine dinucleotide decreased significantly. The most pronounced reduction (35%) was observed for flavin mononucleotide. In the hyperthyroid state, smokers had lower levels of folate and flavin mononucleotide than non-smokers. After restoration of euthyroidism, both folate and riboflavin were significantly lower in smokers than non-smokers. Plasma total homocysteine increased according to decreasing quartiles of B-vitamins. For riboflavin, this relation was confined to smokers.

CONCLUSION

Plasma total homocysteine changes according to thyroid status. These changes may be partly attributable to altered folate, cobalamin but also riboflavin status, particularly in smokers.

[The connection between vitamin and antioxidant status of the children with decreased hemoglobin level]

The investigation of vitamin sufficiency of 96 children 4-15 years old living in Moscow with decreased hemoglobin level (less 120 g/l) has been carried out in spring in 2001. Most of the children (90 per cent) had the combined deficiency of B group vitamins and carotenoids while they were sufficiently vitamin C supplied. There were only 2 per cent of children adequately supplied with all vitamins. Range correlation between hemoglobin blood level and riboflavin and tocopherols serum concentration has been observed. Marked negative linear correlation between riboflavin and malone dialdehyde serum content has been revealed: more sufficiently supplied with vitamin B2 child has lower lipid oxidative product level. Thus the necessity of vitamin B2 including in complex therapy of iron deficiency is based.

High doses of riboflavin and the elimination of dietary red meat promote the recovery of some motor functions in Parkinson's disease patients

Abnormal riboflavin status in the absence of a dietary deficiency was detected in 31 consecutive outpatients with Parkinson's disease (PD), while the classical determinants of homocysteine levels (B6, folic acid, and B12) were usually within normal limits. In contrast, only 3 of 10 consecutive outpatients with dementia without previous stroke had abnormal riboflavin status. The data for 12 patients who did not complete 6 months of therapy or did not comply with the proposed treatment paradigm were excluded from analysis. Nineteen PD patients (8 males and 11 females, mean age +/- SD = 66.2+/-8.6 years; 3, 3, 2, 5, and 6 patients in Hoehn and Yahr stages I to V) received riboflavin orally (30 mg every 8 h) plus their usual symptomatic medications and all red meat was eliminated from their diet. After 1 month the riboflavin status of the patients was normalized from 106.4+/-34.9 to 179.2+/-23 ng/ml (N = 9). Motor capacity was measured by a modification of the scoring system of Hoehn and Yahr, which reports motor capacity as percent. All 19 patients who completed 6 months of treatment showed improved motor capacity during the first three months and most reached a plateau while 5/19 continued to improve in the 3- to 6-month interval. Their average motor capacity increased from 44 to 71% after 6 months, increasing significantly every month compared with their own pretreatment status (P < 0.001, Wilcoxon signed rank test). Discontinuation of riboflavin for several days did not impair motor capacity and yellowish urine was the only side effect observed. The data show that the proposed treatment improves the clinical condition of PD patients. Riboflavin-sensitive mechanisms involved in PD may include glutathione depletion, cumulative mitochondrial DNA mutations, disturbed mitochondrial protein complexes, and abnormal iron metabolism. More studies are required to identify the mechanisms involved.

Assessment of thiamin (vitamin B1) and riboflavin (vitamin B2) status in an adult Mediterranean population

The aim of the present study was to assess the nutritional status for thiamin (vitamin B1) and riboflavin (vitamin B2) in an adult Mediterranean population, in order to identify patterns of intake, groups at risk for deficiency and factors that might influence this risk. A cross-sectional survey was carried out in Andalusia, a western Mediterranean region in southern Spain. Nutrient intakes were studied in a random sample of 3390 subjects (1746 men, 1644 women) who were between 25 and 60 years of age. Blood samples were obtained for biochemical assays in a random subsample of 372 subjects (181 men, 191 women). Food consumption was assessed by 48 h recall. Vitamin B1 and B2 were measured as erythrocyte transketolase and as erythrocyte glutathione reductase activation coefficients, respectively. Energy and vitamin intakes were significantly higher in men than in women. Intakes were below two-thirds of the recommended dietary allowance for vitamin B1 in 7.80 % of the men and 4.50 % of the woman, and were below this level for vitamin B2 in 18.00 % of the men and 11.70 % of the women. Age, educational level, alcohol use and smoking were also associated with differences in the intake of these nutrients. Biochemical analyses showed that vitamin B1 and B2 status was deficient in 6.40 and 5.30 % of the population, respectively. Although factors such as gender, age, level of education, drinking and smoking can have an effect on the risk of inadequate intake of these nutrients, these factors did not affect biochemical indices of nutritional status in the present study.

Effect of riboflavin status on the homocysteine-lowering effect of folate in relation to the MTHFR (C677T) genotype

BACKGROUND

Riboflavin (vitamin B(2)) is the precursor for FAD, the cofactor for methylenetetrahydrofolate reductase (MTHFR). MTHFR catalyzes the formation of 5-methyltetrahydrofolate, which acts as a methyl donor for homocysteine remethylation. Individuals with the MTHFR 677C-->T mutation have increased plasma total homocysteine (tHcy) concentrations, particularly in association with low folate status. It has been proposed that riboflavin may act together with folate to lower plasma tHcy, particularly in individuals with the thermolabile MTHFR T variant.

METHODS

We measured B-vitamin status and plasma tHcy in 126 healthy individuals 20-63 years of age (42 CC, 42 CT, and 42 TT MTHFR genotypes) at baseline and after three interventions (4 months): placebo plus natural diet; daily 400 microg folic acid supplement plus natural diet; and increased dietary folate to 400 microg/day.

RESULTS

At baseline and after nutritional intervention, lower riboflavin status was associated with increased plasma tHcy concentrations. Plasma tHcy was 2.6 micromol/L higher in the lowest plasma riboflavin quartile compared with the highest (P <0.02) and was 4.2 micromol/L higher in the highest erythrocyte glutathione reductase activation coefficient (EGRAC) quartile compared with the lowest (P <0.001). This effect was not restricted to those with the T allele. Folic acid given as a 400 microg/day supplement appeared to exacerbate a tendency toward riboflavin deficiency, as suggested by an increase in the proportion of individuals with EGRAC > or =1.4 from 52% to 65% after supplementation (P <0.05).

CONCLUSIONS

Folate and riboflavin interact to lower plasma tHcy, possibly by maximizing the catalytic activity of MTHFR. The effect may be unrelated to MTHFR genotype.

Normal riboflavin status in malaria patients in Gabon

Previous publications reported commonly the occurrence of riboflavin deficiency and a positive correlation between riboflavin status and parasitemia in patients with Plasmodium falciparum malaria. In these studies, riboflavin status was determined by erythrocyte glutathione reductase activation coefficients (EGRACs). Inherited low erythrocyte glutathione reductase activity is highly prevalent in malarial regions, however. To rule out falsely diagnosed riboflavin deficiency in affected patients, we conducted an investigation using a high-performance liquid chromatography method (HPLC) instead of the EGRAC method. In 29 infants (age range, 1-5 years), 22 schoolchildren (age range, 6-12 years), and 33 adolescents and adults (age range, 13-74 years) from Lambaréné, Gabon, with acute P. falciparum malaria, plasma concentrations of riboflavin, flavin mononucleotide (FMN), and flavin adenine dinucleotide (FAD) were measured by HPLC. Results were correlated with parasite densities. Profiles of plasma concentrations of all 3 flavin compounds were within the normal range in all patients. Concentrations of free riboflavin were not different between the 3 age groups. In adolescents and adults, FMN and FAD concentrations were higher than in infants (P = 0.002 and P = 0.001) and schoolchildren (P = 0.003 and P = 0.002). Comparing children with hyperparasitemic and uncomplicated malaria, no difference in the concentrations of either flavin compound was found. Neither the concentrations of free riboflavin nor the concentrations of one of the flavin nucleotides correlated with parasitemia within subgroups of age or of children with uncomplicated and hyperparasitemic malaria. Our data indicate that nutritional riboflavin deficiency might have been overestimated in previous malaria studies and do not support a relationship between flavin concentrations and parasitemia in P. falciparum malaria.

Erythrocyte glutathione reductase activity and riboflavin nutritional status in early-weaned piglets

The reliability of erythrocyte glutathione reductase activity (EGRAC) as an indicator of riboflavin (vitamin B2) status was determined in 36 piglets weaned at two weeks of age. Total B2 metabolites determined by high-performance liquid chromatography (HPLC) in plasma, red blood cells, and liver were used as reference values. There was no correlation between EGRAC values and total B2 metabolites either in circulation (r < 0.15, p > 0.08) or in liver (r < 0.01, p > 0.95). EGRAC does not appear to be a reliable biochemical indicator of vitamin B2 status in the pig.

The effect of B-vitamins on hyperhomocysteinemia in patients on antiepileptic drugs

Patients on antiepileptic drugs (AEDs) may have elevated levels of plasma total homocysteine (p-tHcy). The aim of this study was to assess the effect of B-vitamin supplementation on the levels of p-tHcy and markers of endothelial activation and lipid peroxidation. A total of 33 adult patients on AEDs were identified with either fasting (Group 1, n=23) or post methionine load (PML) (Group 2, n=10) hyperhomocysteinemia. Subjects were supplemented with B-vitamins for 30 days: folic acid 0.4 mg, pyridoxine 120 mg and riboflavin 75 mg per day. After supplementation, serum folate and pyridoxal phosphate had increased, while fasting and PML p-tHcy had decreased (P<0.0001) by 36 and 26%, respectively. Prior to supplementation, the Group 1 patients had elevated levels of P-selectin and von Willebrand factor (vWF) (P=0.05 and 0.03, respectively). After supplementation, the levels of intercellular cell adhesion molecules had decreased (P=0.01) and E-selectin decreased nonsignificantly (P=0.07). However, the levels of vascular cell adhesion molecules had increased (P<0.0001), while lipid peroxidation were unchanged. In conclusion, the combined supplementation with folic acid, pyridoxine and riboflavin reduced fasting and PML hyperhomocysteinemia in patients on AEDs. Patients with fasting hyperhomocysteinemia had elevated levels of P-selectin and vWF, which may indicate an increased risk of cardiovascular disease. Furthermore, B-vitamin supplementation influenced endothelial activation, although the clinical implication is uncertain.

Riboflavin, flavin mononucleotide, and flavin adenine dinucleotide in human plasma and erythrocytes at baseline and after low-dose riboflavin supplementation

BACKGROUND

Vitamin B(2) exists in blood as riboflavin and its cofactors, flavin mononucleotide (FMN) and FAD. The erythrocyte glutathione reductase activation coefficient (EGRAC) has traditionally been used to assess vitamin B(2) status in humans. We investigated the relationships of EGRAC and plasma and erythrocyte concentrations of riboflavin, FMN, and FAD in elderly volunteers and their responses to riboflavin administration.

METHODS

EGRAC and plasma and erythrocyte concentrations of riboflavin, FMN, and FAD were determined in 124 healthy individuals with a mean age of 69 years. The same measurements were made in a subgroup of 46 individuals with EGRAC > or =1.20 who participated in a randomized double-blind 12-week intervention study and received riboflavin (1.6 mg/day; n = 23) or placebo (n = 23).

RESULTS

Median plasma concentrations were 10.5 nmol/L for riboflavin, 6.6 nmol/L for FMN, and 74 nmol/L for FAD. In erythrocytes, there were only trace amounts of riboflavin, whereas median FMN and FAD concentrations were 44 and 469 nmol/L, respectively. Erythrocyte FMN and FAD correlated with each other and with EGRAC and plasma riboflavin (P <0.05). All variables except plasma FAD responded significantly to riboflavin supplementation compared with placebo (P < or =0.04). The strongest increases were for riboflavin in plasma (83%) and for FMN in erythrocytes (87%).

CONCLUSIONS

Concentrations of all B(2) vitamers except plasma FAD are potential indicators of vitamin B(2) status, and plasma riboflavin and erythrocyte FMN may be useful for the assessment of vitamin B(2) status in population studies.

Impaired functioning of thermolabile methylenetetrahydrofolate reductase is dependent on riboflavin status: implications for riboflavin requirements

BACKGROUND

Methylenetetrahydrofolate reductase (MTHFR; EC 1.7.99.5) supplies the folate needed for the metabolism of homocysteine. A reduction in MTHFR activity, as occurs in the homozygous state for the 677C-->T (so-called thermolabile) enzyme variant (TT genotype), is associated with an increase in plasma total homocysteine (tHcy).

OBJECTIVE

In vitro studies suggest that the reduced activity of thermolabile MTHFR is due to the inappropriate loss of its riboflavin cofactor. We investigated the hypothesis that MTHFR activity in the TT genotype group is particularly sensitive to riboflavin status.

DESIGN

We studied tHcy and relevant B-vitamin status by MTHFR genotype in a cross-sectional study of 286 healthy subjects aged 19-63 y (median: 27 y). The effect of riboflavin status was examined by dividing the sample into tertiles of erythrocyte glutathionine reductase activation coefficient, a functional index of riboflavin status.

RESULTS

Lower red blood cell folate (P = 0.0001) and higher tHcy (P = 0.0082) concentrations were found in the TT group than in the heterozygous (CT) or wild-type (CC) groups. However, these expected relations in the total sample were driven by the TT group with the lowest riboflavin status, whose mean tHcy concentration (18.09 micromol/L) was almost twice that of the CC or CT group. By contrast, adequate riboflavin status rendered the TT group neutral with respect to tHcy metabolism.

CONCLUSIONS

The high tHcy concentration typically associated with homozygosity for the 677C-->T variant of MTHFR occurs only with poor riboflavin status. This may have important implications for governments considering new fortification policies aimed at the prevention of diseases for which this genotype is associated with increased risk.

Reduced serum concentrations of riboflavine and ascorbic acid, and blood thiamine pyrophosphate and pyridoxal-5-phosphate in geriatric patients with and without pressure sores

BACKGROUND

Patients with pressure sores have as part of their treatment been reefed with energy and proteins with varying result. It has been uncertain, however, to what an extent these patients also were depleted of micronutrients which might be critical for ulcer healing.

OBJECTIVE

To study the nutritional intake and nutritional status of a number of micronutrients in geriatric pressure sore patients and in matched controls.

DESIGN

The nutritional intake and nutritional status as anthropometric measures, serum conc. of albumin, zinc, and of vitamins (ascorbic acid, riboflavin, calcidiol), were measured. Thiamin pyrophosphate and pyridoxal-5-phosphate were determined in whole blood from 11 geriatric in-patients with pressure sores and 11 matched controls.

RESULTS

The serum conc. of ascorbic acid was significantly (p< 0.05) more reduced in pressure sore patients (mean+/-S.D.) 4.2+/-3.4 (ug/ml) than in control patients 7.4+/-5.4 (ug/ml) which still was lower than in a reference group (10.9+/-1.9) (ug/ml). In all the geriatric patients compared to the reference group, the conc. of serum-riboflavin was reduced to about 15 %, thiamine-pyrophosphate and pyridoxine-5-phosphate in whole blood and serum calcidiol to about 50 %, without any differences between the pressure sore patients and the matched controls.

CONCLUSION

Refeeding of pressure sore patients who often are catabolic and have increased needs for protein and energy, should include micronutrients not only to cover recommended dietary allowances, but sufficient to reach normal nutritional status for the individual micronutrient.