Mutations in the genes encoding the alpha-subunit and beta-subunit of the mitochondrial electron transfer flavoprotein (ETF) and the electron transfer flavoprotein:ubiquinone oxidoreductase (ETF:QO) cause multiple acyl-CoA dehydrogenation deficiency (MADD), a disorder of fatty acid and amino acid metabolism. Point mutations in ETF, which may compromise folding, and/or activity, are associated with both mild and severe forms of MADD. Here we report the investigation on the conformational and stability properties of the disease-causing variant ETFbeta-D128N, and our findings on the effect of flavinylation in modulating protein conformational stability and activity. A combination of biochemical and biophysical methods including circular dichroism, visible absorption, flavin, and tryptophan fluorescence emission allowed the analysis of structural changes and of the FAD moiety. The ETFbeta-D128N variant retains the overall fold of the wild type, but under stress conditions its flavin becomes less tightly bound. Flavinylation is shown to improve the conformational stability and biological activity of a destabilized D128N variant protein. Moreover, the presence of flavin prevented proteolytic digestion by avoiding protein destabilization. A patient homozygous for the ETFbeta-D128N mutation developed severe disease symptoms in association with a viral infection and fever. In agreement, our results suggest that heat inactivation of the mutant may be more relevant at temperatures above 37 degrees C. To mimic a situation of fever in vitro, the flavinylation status was tested at 39 degrees C. FAD exerts the effect of a pharmacological chaperone, improving ETF conformation, and yielding a more stable and active enzyme. Our results provide a structural and functional framework that could help to elucidate the role that an increased cellular FAD content obtained from riboflavin supplementation may play in the molecular pathogenesis of not only MADD, but genetic disorders of flavoproteins in general.

OBJECTIVE

We report a case of failure of corneal collagen cross-linking (CXL) for progressive keratoconus after preoperative stromal swelling with hypoosmolar riboflavin solution in an extremely thin cornea.

METHODS

CXL was performed using the protocol established for the treatment of thin corneas. Preoperative minimal thickness after abrasion was 268 μm and increased to 406 μm after swelling with hypoosmolar riboflavin solution.

RESULTS

Despite CXL, a distinct progression of up to 1.9 diopters was observed at 3 months after the procedure on the anterior corneal surface. At 6 months after CXL, progression had increased to 2.3 diopters. Although swelling with hypoosmolar riboflavin solution was effective and led to a preoperative thickness of more than 400 μm, the increase in biomechanical resistance was not sufficient to arrest the progression of the disease.

CONCLUSIONS

Little is known about the minimal stromal thickness required for effective CXL to occur. Although swelling with hypoosmolar riboflavin solution over 400 μm and safety of the procedure can be achieved in even thinner corneas, the outcome of this case suggests that a minimal preoperative stromal thickness of 330 μm needs to be respected for a successful CXL procedure.

The possibility that the taking of vitamin supplements may influence mood was explored. One hundred and twenty-nine young healthy adults took either 10 times the recommended daily dose of 9 vitamins, or a placebo, under a double-blind procedure, for a year. Males taking the vitamins differed from those taking the placebo in that they reported themselves as feeling more 'agreeable' after 12 months. After 12 months the mood of females taking the vitamin supplement was significantly improved in that they felt more 'agreeable', more composed and reported better mental health. These changes in mood after a year occurred even though the blood status of 9 vitamins reached a plateau after 3 months: this improvement in mood was associated in particular with improved riboflavin and pyridoxine status. In females baseline thiamin status was associated with poor mood and an improvement in thiamin status after 3 months was associated with improved mood.

BACKGROUND

Collagen cross-linking of the cornea has been shown by us to have an antiedematous effect in the cornea. The aim of the present study was to examine if this effect can be used for the treatment of bullous keratopathy.

METHODS

This clinical interventional case series included 3 patients (3 eyes) with bullous keratopathy due to pseudophakia, corneal transplant rejection, and Fuchs' endothelial dystrophy. After dehydration for 1 day using 40% glucose, the central 8 mm of the cornea were abraded and cross-linked with the photosensitizer riboflavin and UVA (370 nm, 3 mW/cm(2)) for 30 min. Optical coherence tomography pachymetry measurements of the central cornea were performed at various time intervals.

RESULTS

Corneal thickness was reduced by 90.33 +/- 17.04 microm on average 3 days after cross-linking and by 93.67 +/- 14.22 microm after 8 months. The bullous changes of the epithelium were markedly improved, resulting in loss of pain and discomfort. Visual acuity was significantly improved in the case without prior stromal scarring.

CONCLUSIONS

Cross-linking might become another useful tool in the treatment of bullous keratopathy. It is primarily suited for patients with pain symptoms, restricted visual prognosis or to extend the time interval for an upcoming corneal transplantation.

In this study, we describe the nutritional status of women from a South African community with very high rates of fetal alcohol spectrum disorders (FASD). Nutrient intake (24-h recall) of mothers of children with FASD was compared to mothers of normal controls. Nutrient adequacy was assessed using Dietary Reference Intakes (DRIs). More than 50% of all mothers were below the Estimated Average Requirement (EAR) for vitamins A, D, E, and C, thiamin, riboflavin, vitamin B6, folate, calcium, magnesium, iron, and zinc. Mean intakes were below the Adequate Intake (AI) for vitamin K, potassium, and choline. Mothers of children with FASD reported significantly lower intake of calcium, docosapentaenoic acid (DPA), riboflavin, and choline than controls. Lower intake of multiple key nutrients correlates significantly with heavy drinking. Poor diet quality and multiple nutritional inadequacies coupled with prenatal alcohol exposure may increase the risk for FASD in this population.

The risk of endometrial cancer is positively associated with obesity, but the role of specific nutrients remains unclear. Given the distinct characteristics of the Greek diet and the low incidence of this form of cancer among Greek women, we undertook a case-control study to investigate the association of endometrial cancer with food groups and micronutrients. Cases were 84 women with histologically confirmed endometrial cancer and controls were 84 women with intact uterus admitted to the same teaching hospital in Athens, Greece. Consumption of pulses, nuts, and seeds was significantly inversely related to the risk for endometrial cancer. No other significant association with food groups was detected, although a protective effect of added lipids, which in the Greek diet are primarily represented by olive oil, was highly suggestive. Retinol, nicotinic acid, vitamin B- 6, and riboflavin were inversely associated with the disease. These findings need to be replicated, because this was a relatively small study with the statistical power to detect only strong associations between cases and controls; they appear, however, to support a role of diet in the etiology of endometrial cancer.

Migraine is a common disorder in childhood and adolescence. Studies on adults show the effectiveness and tolerability of riboflavin in migraine prevention, while data on children are scarce. This retrospective study reports on our experience of using riboflavin for migraine prophylaxis in 41 pediatric and adolescent patients, who received 200 or 400 mg/day single oral dose of riboflavin for 3, 4 or 6 months. Attack frequency and intensity decreased (P < 0.01) during treatment, and these results were confirmed during the follow-up. A large number of patients (77.1%) reported that abortive drugs were effective for controlling ictal events. During the follow-up, 68.4% of cases had a 50% or greater reduction in frequency of attacks and 21.0% in intensity. Two patients had vomiting and increased appetite, respectively, most likely for causes unrelated to the use of riboflavin. In conclusion, riboflavin seems to be a well-tolerated, effective, and low-cost prophylactic treatment in children and adolescents suffering from migraine.

BACKGROUND

Previously we showed that women in rural Nepal experience multiple micronutrient deficiencies in early pregnancy.

OBJECTIVE

This study examined the effects of daily antenatal micronutrient supplementation on changes in the biochemical status of several micronutrients during pregnancy.

METHODS

In Nepal, we conducted a randomized controlled trial in which 4 combinations of micronutrients (folic acid, folic acid + iron, folic acid + iron + zinc, and a multiple micronutrient supplement containing folic acid, iron, zinc, and 11 other nutrients) plus vitamin A, or vitamin A alone as a control, were given daily during pregnancy. In a subsample of subjects (n = 740), blood was collected both before supplementation and at approximately 32 wk of gestation.

RESULTS

In the control group, serum concentrations of zinc, riboflavin, and vitamins B-12 and B-6 decreased, whereas those of copper and alpha-tocopherol increased, from the first to the third trimester. Concentrations of serum folate, 25-hydroxyvitamin D, and undercarboxylated prothrombin remained unchanged. Supplementation with folic acid alone or folic acid + iron decreased folate deficiency. However, the addition of zinc failed to increase serum folate, which suggests a negative inhibition; multiple micronutrient supplementation increased serum folate. Folic acid + iron + zinc failed to improve zinc status but reduced subclinical infection. Multiple micronutrient supplementation decreased the prevalence of serum riboflavin, vitamin B-6, vitamin B-12, folate, and vitamin D deficiencies but had no effect on infection.

CONCLUSIONS

In rural Nepal, antenatal supplementation with multiple micronutrients can ameliorate, to some extent, the burden of deficiency. The implications of such biochemical improvements in the absence of functional and health benefits remain unclear.

BACKGROUND

The methodology used in the first Belgian food consumption survey followed to a large extent the instructions of the European Food Consumption (EFCOSUM) reports, where repeated 24-hour recalls (24HR) using EPIC-SOFT were recommended.

OBJECTIVE

To evaluate the relative validity of two non-consecutive 24HR using EPIC-SOFT by comparison with 5-day estimated dietary records (EDR). To assess misreporting in energy for both methods by comparing energy intake with energy expenditure from accelerometery in a subsample.

METHODS

A total of 175 subjects (aged 15 and over) were recruited to participate in the study. Repeated 24HR were performed with an interval of 2-8 weeks. After completion of the second interview, subjects were instructed to keep an EDR. Dietary intakes were adjusted for within-person variability to reflect usual intakes. A Student's t-test was calculated to assess differences between both methods. Spearman and Kappa correlation coefficients were used to investigate agreement.

RESULTS

In total, 127 subjects completed the required repeated 24HR, as well as the five record days. From 76 participants, accelerometer data were available. In both methods, about 35% of participants had ratios of Energy Intake/Total Energy Expenditure (EI/TEE) above or below 95% confidence intervals for EI/TEE, suggesting misreporting of energy. Significant differences between the two dietary intake methods were found for total energy, total fat, fatty acids, cholesterol, alcohol, vitamin C, thiamine, riboflavin and iron. In general, intakes from 24HR were higher compared to EDR. Correlation coefficients for all nutrients ranged from 0.16 for thiamine to 0.70 for water.

CONCLUSIONS

The results from this study show that in the context of nutritional surveillance, duplicate 24HR can be used to asses intakes of protein, carbohydrates, starch, sugar, water, potassium and calcium.

The effects of water-soluble vitamins, singly or in combinations, on development of hamster 1-cell embryos were examined in a protein-free, chemically defined culture medium, HECM-6. Pantothenate significantly stimulated blastocyst development compared to the vitamin-free control and to every other single vitamin, except thiamine. Ascorbic acid, biotin, choline, folic acid, inositol, niacinamide, pyridoxal, riboflavin and thiamine had no detectable stimulation or inhibition on cleavage stage development or morula/blastocyst formation. When combinations of vitamins were tested, embryo development was either unchanged or significantly greater than in the control, but never significantly greater than development with pantothenate alone. A dose response to pantothenate indicated that 3 micromol/l was the optimum concentration. After embryo transfer, the percentage of live fetuses recovered per 100 1-cell embryos cultured in HECM-6 plus pantothenate (now designated HECM-9) was 24%, significantly higher than the 11% recovered from 100 1-cell embryos cultured in HECM-6 alone. This is the first report to show a stimulatory effect of a single vitamin on in-vitro development of preimplantation embryos in any mammalian species.

BACKGROUND

There is growing interest in possible dietary involvement in the aetiology and treatment of Autistic Spectrum Disorders (ASD). Research has focused on the physiological and behavioural effects of dietary change but has not examined the effect of exclusion diets on nutritional intake.

OBJECTIVE

The aim of this study was to examine whether the removal of major dietary staples placed children with autism at risk of nutrient deficiency and compares their food choice with ASD children not following gluten and/or casein free diets.

METHODS

A postal questionnaire was sent to parents of children aged 3-16 years, diagnosed with ASD belonging to the National Autistic Society in Leicestershire and southern Derbyshire. Detailed dietary information and a 3-day food diary were collected. The sample size was small: those using gluten/casein free diets (n = 8) and those not following diet (n = 29).

RESULTS

Nutrient intakes fell below the Lower Reference Nutrient Intake (LRNI) in 12 children (32%) for zinc, calcium, iron, vitamin A, vitamin B12 and riboflavin in the nondiet group and four children (50%) for zinc and calcium in the diet group. Fruit and vegetable intakes were higher and cereal, bread and potato consumption were lower in those children using gluten and/or casein free diets.

CONCLUSIONS

No significant differences in the energy, protein and micronutrient intakes were found between the two groups of children. A longitudinal prospective study is suggested to examine whether differences in food choice are the result of dietary intervention or the prerequisite for the successful application of diet in this special group of children.

Glutathione reductase of hemolyzates from clinically normal subjects is activated by the addition of flavin-adenine dinucleotide. One-half maximum stimulation could be achieved by approximately 0.02 micromolar flavin-adenine dinucleotide; prior addition of adenosine triphosphate, adenosine diphosphate, or adenosine mnonophosphate prevented activation. Stimulation of glutathione reductase activity of red cells of normal subjects occurred when they were given 5 milligrams of riboflavin daily for 8 days. The degree of stimulation in vitro by flavin-adenine dinucleotide and in vivo by riboflavin was inversely proportional to dietary intake of riboflavin. The variety of clinical disorders which have been associated with glutathione reductase deficiency may have, as a common denominator, abnormalities in flavin-adenine dinucleotide formation.

OBJECTIVE

To compare 2 sequences of combined intrastromal corneal ring segment (ICRS) implantation and ultraviolet/riboflavin-mediated corneal collagen crosslinking (CXL) in progressive keratoconus.

METHODS

Dunya Eye Hospital, Istanbul, Turkey.

METHODS

In this prospective comparative randomized consecutive study, CXL was followed by ICRS implantation (Group 1) or ICRS implantation was followed by CXL (Group 2). Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, spherical equivalent (SE), manifest cylinder (cylinder), and mean keratometry (K) were compared preoperatively and postoperatively.

RESULTS

The mean interval between treatments was 7 months +/- 2 (SD) (mean follow-up, 13 +/- 1 months). The mean UDVA and CDVA improved in both groups (UDVA: 0.07 +/- 0.09 to 0.25 +/- 0.12, Group 1, and 0.11 +/- 0.09 to 0.32 +/- 0.21, Group 2; CDVA: 0.24 +/- 0.11 to 0.41 +/- 0.20 and 0.22 +/- 0.16 to 0.55 +/- 0.2, respectively). The mean SE, cylinder, and mean K values decreased in both groups (SE: -7.13 +/- 3.34 D to -2.98 +/- 2.33 D, Group 1, and -7.05 +/- 5.54 D to -2.81 +/- 4.08 D, Group 2; cylinder: -4.38 +/- 2.03 D to -2.62 +/- 1.93 D and -4.68 +/- 2.60 D to -2.20 +/- 1.67 D, respectively; mean K: 52.47 +/- 4.01 D to 48.31 +/- 3.65 D and 52.06 +/- 4.93 D to 48.08 +/- 4.13 D, respectively). Overall, there was more improvement in CDVA, SE, and mean K in Group 2 than in Group 1.

CONCLUSIONS

Implantation of ICRS followed by CXL resulted in greater improvement of keratoconus.

OBJECTIVE

To determine long-term efficacy and safety of riboflavin/ultraviolet A corneal cross-linking (CXL).

METHODS

Prospective cohort study.

METHODS

Thirty-six patients (36 eyes) who underwent epithelium-off CXL at a University Hospital (Guy's and St Thomas' National Health Service Foundation Trust) 6-8 years previously were examined. The main outcome measures were refractive error, visual acuity, corneal topographic keratometry, ultrasonic pachymetry, and topography-derived corneal wavefront.

RESULTS

At 7 years compared to preoperative values, mean spherical equivalent refractive error (SEQ) increased by +0.78 diopter (D) (P < .005) and mean simulated topographic keratometry (SimK) and mean maximum keratometry (Kmax) reduced by -0.74 D (P < .0001) and -0.91 D (P < .0001), respectively. Uncorrected distance acuity (UCDA) (P < .0005) and corrected distance acuity (CDVA) (P < .0001) had improved and root mean square (RMS) (P < .0005), coma (P < .0005), and secondary astigmatism (P < .005) lessened. At 7 years compared to 1 year, CDVA improved (P < .05); mean SimK (P < .0005) and mean Kmax (P < .005) reduced by -0.45 D and -0.56 D, respectively; and RMS (P < .0005) and coma (P < .0005) decreased. At 7 years compared to 5 years, CDVA improved (P < .05) and trefoil reduced (P < .05). No treated eyes progressed. In 29 initially untreated fellow eyes mean SimK increased by +0.54 D (P < .02), mean Kmax by +0.87 D (P < .05), and refractive astigmatism increased (P < .0005).

CONCLUSIONS

Following corneal cross-linking, improvements in topographic and wavefront parameters evident at 1 year were seen to continue to improve at 5 years and were maintained at 7 years. No treated eyes progressed over the 7-year follow-up period.

Mucosa-associated invariant T (MAIT) cells are unconventional innate-like T cells that recognize microbial riboflavin metabolites presented by the MHC class I-like protein MR1. Human MAIT cells predominantly express the CD8α coreceptor (CD8+), with a smaller subset lacking both CD4 and CD8 (double-negative, DN). However, it is unclear if these two MAIT cell subpopulations distinguished by CD8α represent functionally distinct subsets. Here, we show that the two MAIT cell subsets express divergent transcriptional programs and distinct patterns of classic T cell transcription factors. Furthermore, CD8+ MAIT cells have higher levels of receptors for IL-12 and IL-18, as well as of the activating receptors CD2, CD9, and NKG2D, and display superior functionality following stimulation with riboflavin-autotrophic as well as riboflavin-auxotrophic bacterial strains. DN MAIT cells display higher RORγt/T-bet ratio, and express less IFN-γ and more IL-17. Furthermore, the DN subset displays enrichment of an apoptosis gene signature and higher propensity for activation-induced apoptosis. During development in human fetal tissues, DN MAIT cells are more mature and accumulate over gestational time with reciprocal contraction of the CD8+ subset. Analysis of the T cell receptor repertoire reveals higher diversity in CD8+ MAIT cells than in DN MAIT cells. Finally, chronic T cell receptor stimulation of CD8+ MAIT cells in an in vitro culture system supports the accumulation and maintenance of the DN subpopulation. These findings define human CD8+ and DN MAIT cells as functionally distinct subsets and indicate a derivative developmental relationship.

The proton-pumping NADH:ubiquinone oxidoreductase of Escherichia coli is composed of 14 different subunits and contains one FMN and up to nine iron-sulfur clusters as prosthetic groups. By use of salt treatment, the complex can be split into an NADH dehydrogenase fragment, a connecting fragment and a membrane fragment. The water-soluble NADH dehydrogenase fragment has a molecular mass of approximately 170,000 Da and consists of the subunits NuoE, F, and G. The fragment harbors the FMN and probably six iron-sulfur clusters, four of them being observable by EPR spectroscopy. Here, we report that the fully assembled fragment can be overproduced in E. coli when the genes nuoE, F, and G were simultaneously overexpressed with the genes nuoB, C, and D. Furthermore, riboflavin, sodium sulfide, and ferric ammonium citrate have to be added to the culture medium. The fragment was purified from the cytoplasm by means of ammonium sulfate fractionation and chromatographic steps. The preparation contains one noncovalently bound FMN per molecule. Two binuclear (N1b and N1c) and two tetranuclear (N3 and N4) iron-sulfur clusters were detected by EPR in the NADH reduced preparation with spectral characteristics identical with those of the corresponding clusters in complex I. The preparation fulfills all prerequisites for crystallization of the fragment.

OBJECTIVE

In an attempt to reduce treatment time in corneal collagen cross-linking (CXL) with riboflavin and ultraviolet-A (UV-A), recent protocol modifications include shorter irradiation times at higher fluence, while maintaining constant total applied energy (Bunsen-Roscoe law of reciprocity). While such parameter changes might produce similar biological results within a certain range, the limits of reciprocity are unknown. Limitations in the corneal oxygen diffusion capacity and its potential impact on the efficacy of CXL, raise concerns regarding the efficiency of high-fluence CXL, and also of transepithelial CXL.

METHODS

Porcine corneas were treated with an epithelium-off CXL at a fluence of 9 mW/cm2 under two different atmospheres: one with a regular oxygen content (21%) and another in a helium-supplemented, low-oxygen environment (<0.1%). Untreated corneas served as controls (n = 20 each). Five-millimeter corneal stripes were prepared and biomechanical stiffness was measured using an extensometer.

RESULTS

Corneas cross-linked under normal oxygen levels showed a significant increase in biomechanical stability (14.36 MPa ± 2.69 SD), whereas corneas treated similarly, but in a low-oxygen atmosphere showed a Young's modulus similar to untreated controls (11.72 MPa ± 2.77 SD).

CONCLUSIONS

The biomechanical effect of CXL seems to be oxygen dependent. This dependency will be of particular importance in high-fluence and transepithelial CXL and will most likely require major protocol modifications to maintain the efficiency of the method.

UNASSIGNED

The oxygen dependency of CXL shown here raises concerns about the effectiveness of high-fluence and transepithelial CXL. Both methods were introduced to clinical ophthalmology without thorough validation.

To evaluate the safety and efficacy of corneal collagen crosslinking (CXL) for the treatment of progressive keratoconus.

Prospective, randomized, multicenter, controlled clinical trial.

Patients with progressive keratoconus (n = 205).

The treatment group underwent standard CXL and the sham control group received riboflavin alone without removal of the epithelium.

The primary efficacy criterion was the change over 1 year of topography-derived maximum keratometry value, comparing treatment with control group. Secondary outcomes evaluated were corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), manifest refraction spherical equivalent, endothelial cell count, and adverse events.

In the CXL treatment group, the maximum keratometry value decreased by 1.6 diopters (D) from baseline to 1 year, whereas keratoconus continued to progress in the control group. In the treatment group, the maximum keratometry value decreased by 2.0 D or more in 28 eyes (31.5%) and increased by 2.0 D or more in 5 eyes (5.6%). The CDVA improved by an average of 5.7 logarithm of the minimum angle of resolution (logMAR) units. Twenty-three eyes (27.7%) gained and 5 eyes lost (6.0%) 10 logMAR or more. The UDVA improved 4.4 logMAR. Corneal haze was the most frequently reported CXL-related adverse finding. There were no significant changes in endothelial cell count 1 year after treatment.

Corneal collagen crosslinking was effective in improving the maximum keratometry value, CDVA, and UCVA in eyes with progressive keratoconus 1 year after treatment, with an excellent safety profile. Corneal collagen crosslinking affords the keratoconic patient an important new option to decrease progression of this ectatic corneal process.

OBJECTIVE

To evaluate the safety and efficacy of corneal collagen cross-linking (CXL) by riboflavin/UV light for the treatment of keratoconus.

METHODS

This randomized, prospective, and comparative study involved 10 eyes with keratoconus diagnosed between September 2006 and January 2008. Each patient underwent CXL in the keratoconus eye. Preoperative and postoperative (at 1, 3, 6, and 12 months) biomicroscopy examinations, distance uncorrected and best-corrected visual acuities, refractive error, endothelial cell counts, keratometry readings, ultrasound pachymetry, macular thickness, and Scheimpflug analyses were performed and compared.

RESULTS

Mean uncorrected visual acuity was 1.18 logarithm of the minimum angle of resolution preoperatively and 0.46 logarithm of the minimum angle of resolution at 12 months postoperatively (P < 0.001). Statistically significant reductions in the mean maximum [2.66 diopter (D), P = 0.04] and minimum (1.61 D, P = 0.03) keratometry values were present at 12 months postoperatively, in addition there was a 2.25 D reduction in the mean spherical equivalent (P = 0.01). At the end of follow-up, 8 (80%) and 6 (60%) of the 10 eyes showed a decrease in the anterior and posterior elevation values, respectively, and the thinnest point of the cornea was statistically thinner by a mean of 13.4 μm (P = 0.03). No statistically significant differences were found between preoperative and postoperative endothelial cell counts and macular thicknesses. The improvements in visual acuity, keratometry readings, and spherical equivalent values occurred progressively during follow-up.

CONCLUSIONS

CXL procedure is a safe treatment for keratoconus, yields good visual results, and reduces the progression of the disease, but long follow-up is necessary.

BACKGROUND

Previous animal studies have shown that vitamins may prevent age-related hearing loss. However, no concrete conclusions have been reached about the association between vitamin intake and presbycusis in humans.

OBJECTIVE

We investigated the association between dietary vitamin intake and hearing thresholds in adults between 50 and 80 y of age by using data from a large population-based survey.

METHODS

We used data from the 2011 Korea National Health and Nutrition Examination Survey. A pure-tone audiogram and physical examination of the ear were performed, and vitamin intake was calculated by using the 24-h recall method. Data from 1910 participants were analyzed through univariate and multivariate linear regression analyses.

RESULTS

After adjustment for age, sex, smoking, and exposure to occupational and explosive noise, intake of vitamin C correlated with better hearing at midfrequency (2000 and 3000 Hz) (coefficient: -0.012; 95% CI: -0.022, -0.002). Dietary supplement use was positively associated with better hearing at all frequencies. The univariate analysis indicated that dietary intakes of retinol, riboflavin, niacin, and vitamin C were positively correlated with better hearing at most frequencies. In contrast, serum concentrations of vitamin D were associated with worse hearing at mid and high (4000 and 6000 Hz) frequencies.

CONCLUSIONS

Dietary intake of vitamin C was associated with better hearing in the older population. Because less than one-half of elderly participants in this study consumed a sufficient amount of vitamins, and vitamin intake decreased with age, we should consider proper diet counseling to prevent hearing decline.

BACKGROUND

Mandatory folic acid fortification of food is effective in reducing neural tube defects and may even reduce stroke-related mortality, but it remains controversial because of concerns about potential adverse effects. Thus, it is virtually nonexistent in Europe, albeit many countries allow food fortification on a voluntary basis.

OBJECTIVE

The objective of the study was to examine the effect of a voluntary but liberal food fortification policy on dietary intake and biomarker status of folate and other homocysteine-related B vitamins in a healthy population.

METHODS

The study was a cross-sectional study. From a convenience sample of 662 adults in Northern Ireland, those who provided a fasting blood sample and dietary intake data were examined (n = 441, aged 18-92 y). Intakes of both natural food folate and folic acid from fortified foods were estimated; we used the latter to categorize participants by fortified food intake.

RESULTS

Fortified foods were associated with significantly higher dietary intakes and biomarker status of folate, vitamin B-12, vitamin B-6, and riboflavin than were unfortified foods. There was no difference in natural food folate intake (range: 179-197 microg/d) between the fortified food categories. Red blood cell folate concentrations were 387 nmol/L higher and plasma total homocysteine concentrations were 2 micromol/L lower in the group with the highest fortified food intake (median intake: 208 microg/d folic acid) than in the nonconsumers of fortified foods (0 microg/d folic acid).

CONCLUSIONS

These results show that voluntary food fortification is associated with a substantial increase in dietary intake and biomarker status of folate and metabolically related B vitamins with potential beneficial effects on health. However, those who do not consume fortified foods regularly may have insufficient B vitamin status to achieve the known and potential health benefits.

BACKGROUND

Current data suggest that physiologic doses of vitamin B-6 have no significant homocysteine-lowering effect. It is possible that an effect of vitamin B-6 was missed in previous trials because of a much greater effect of folic acid, vitamin B-12, or both.

OBJECTIVE

The aim of this study was to investigate the effect of low-dose vitamin B-6 supplementation on fasting total homocysteine (tHcy) concentrations in healthy elderly persons who were made replete with folate and riboflavin.

METHODS

Twenty-two healthy elderly persons aged 63-80 y were supplemented with a low dose of vitamin B-6 (1.6 mg/d) for 12 wk in a randomized, double-blind, placebo-controlled trial after repletion with folic acid (400 microg/d for 6 wk) and riboflavin (1.6 mg/d for 18 wk); none of the subjects had a vitamin B-12 deficiency.

RESULTS

Folic acid supplementation lowered fasting tHcy by 19.6% (P < 0.001). After folic acid supplementation, baseline tHcy concentrations ranged from 6.22 to 23.52 micromol/L and 10 subjects had suboptimal vitamin B-6 status (plasma pyridoxal-P < 20 nmol/L). Two-way analysis of variance showed that the significant improvement in vitamin B-6 status in response to vitamin B-6 supplementation (on the basis of both pyridoxal-P: and the erythrocyte aspartate aminotransferase activation coefficient) was reflected in a significant reduction in plasma tHcy of 7.5%.

CONCLUSIONS

Low-dose vitamin B-6 effectively lowers fasting plasma tHcy in healthy subjects who are both folate and riboflavin replete. This suggests that any program aimed at the treatment or prevention of hyperhomocysteinemia should include vitamin B-6 supplementation.

The biosynthesis pathway for riboflavin (vitamin B(2)), the precursor of the essential cofactors flavin mononucleotide and flavin adenine dinucleotide, is present in bacteria and plants but is absent in vertebrates. Due to their conservation in bacterial species and their absence in humans, the riboflavin synthesis genes should be well suited either for detection of bacterial DNA in human specimens or for the differentiation of pathogenic bacteria by molecular techniques. A DNA fragment carrying the genes ribD, ribC, and ribE, which encode homologues of riboflavin deaminase (RibD) and subunits of riboflavin synthetase (RibC and RibE), respectively, was isolated from a plasmid-based DNA library of the human pathogen Bartonella henselae by complementation of a ribC mutation in Escherichia coli. Sequence analysis of the ribC gene region in strains of B. henselae, which were previously shown to be genetically different, revealed that the ribC gene is highly conserved at the species level. PCR amplification with primers derived from the ribC locus of B. henselae was used to isolate the corresponding DNA regions in B. bacilliformis, B. clarridgeiae, and B. quintana. Sequence analysis indicated that the riboflavin synthesis genes are conserved and show the same operon-like genetic organization in all four Bartonella species. Primer oligonucleotides designed on the basis of localized differences within the ribC DNA region were successfully used to develop species-specific PCR assays for the differentiation of B. henselae, B. clarridgeiae, B. quintana, and B. bacilliformis. The results obtained indicate that the riboflavin synthesis genes are excellent targets for PCR-directed differentiation of these emerging pathogens. The PCR assays developed should increase our diagnostic potential to differentiate Bartonella species, especially B. henselae and the newly recognized species B. clarridgeiae.

We studied seven male wrestlers and three judo athletes (weight 55-93 kg) during two weight reductions. In the "gradual" procedure (GP), a 5.0 +/- 0.4% (mean +/- SEM) weight loss was achieved in 3 weeks by energy restriction. In the "rapid" procedure (RP), 6.0 +/- 0.6% of body weight was lost in 2.4 days by fluid and diet restriction and forced sweating, and followed by a 5-h "loading" (food and drinks ad libitum). The net weight loss after GP and loading was 2.7 +/- 0.5%. Protein intakes (4-d food records) during GP and RP were 71 +/- 16 and RP 56 +/- 17 g.d-1, respectively. Carbohydrate intakes were 239 +/- 56 (GP) and 182 +/- 55 g.d-1 (RP). During GP and RP, mean thiamin, magnesium, and zinc intakes were at or below the respective recommendation. Thiamin, riboflavin, potassium, iron, and zinc status, assessed from blood chemistry, remained stable during both procedures. Changes in vitamin B6 indicator (E-ASTAC) and S-magnesium concentration were different (P < 0.01) between the procedures, suggesting negative trends during GP. Sprint (30-m run) and anaerobic (1-min Wingate test) performance was similar throughout the study. Following GP, vertical jump height with extra load increased by 6-8% (P < 0.01). Jumping results were not affected by RP. Hence, < or = 5% loss in body weight by either method did not impair experienced athletes' performance.