The second National Health and Nutrition Examination Survey, 1976 to 1980, incorporated medical history, physical examination, anthropometric measurements, dietary information (24-hour recall and food frequency), laboratory tests, and radiographs. In linear regressions of adjusted data from 2,695 children aged 7 years and younger, 91% of the variance in height, 72% of the variance in weight, and 58% of the variance in chest circumference were explained by six variables: age, race, sex, blood lead level, total calories or protein, and hematocrit or transferrin saturation level. Variables that did not significantly improve the models predicting growth included family income, degree of urbanization, serum albumin, copper, iron, and zinc levels, dietary carbohydrate, fat, calcium, potassium, phosphorus, vitamin A, vitamin C, niacin, riboflavin, and thiamine. The highly significant correlation of blood lead level with growth does not contradict the established association of childhood deprivation with increased lead exposure and with nutritional deficiences known to enhance lead absorption. Blood lead level may also represent a composite marker for unidentified genetic, ethnic, environmental, and sociocultural variables, other than race, sex, and nutrition, that affect growth. However, the correlation of stature, particularly height, with blood lead levels in the range of 5 to 35 micrograms/dL is so statistically significant that it merits investigation in other surveys and consideration of the multiple biologic mechanisms by which low-level lead exposure could impair the growth of children.

BACKGROUND

Some pregnant women may be advised or choose to restrict milk consumption and may not take appropriate supplements. We hypothesized that maternal milk restriction during pregnancy, which can reduce intakes of protein, calcium, riboflavin and vitamin D, might represent a health risk by lowering infant birth weight.

METHODS

We screened women between the ages of 19 and 45 years who were attending prenatal programs in Calgary, Alberta (51 degrees N) for low milk consumption (< or = 250 mL/d). Using repeat dietary recalls, we compared these women and their offspring with women whose daily milk consumption exceeded 250 mL (1 cup). Birth weight, length and head circumference were obtained from birth records.

RESULTS

Women who consumed < or = 250 mL/d of milk (n = 72) gave birth to infants who weighed less than those born to women who consumed more (n = 207; 3410 g v. 3530 g, respectively; p = 0.07). Infant lengths and head circumferences were similar. Women who restricted milk intake had statistically significantly lower intakes of protein and vitamin D as well. In multivariate analyses controlled for previously established predictors of infant birth weight, milk consumption and vitamin D intake were both significant predictors of birth weight. Each additional cup of milk daily was associated with a 41 g increase in birth weight (95% confidence interval [CI] 14.0-75.1 g); each additional microgram of vitamin D, with an 11 g increase (95% CI 1.2-20.7 g). Neither protein, riboflavin nor calcium intake was found to predict birth weight.

CONCLUSIONS

Milk and vitamin D intakes during pregnancy are each associated with infant birth weight, independently of other risk factors.

BACKGROUND

Iron and zinc deficiency are prevalent during infancy in low-income countries.

OBJECTIVE

The objectives were to examine whether a weekly supplement of iron, zinc, iron+zinc, or a micronutrient mix (MM) of 16 vitamins and minerals would alter infant development and behavior.

METHODS

The participants were 221 infants from rural Bangladesh at risk of micronutrient deficiencies. Development and behavior were evaluated at 6 and 12 mo of age by using the Bayley Scales of Infant Development II and the Home Observation Measurement of Environment (HOME) scale. In this double-blind trial, the infants were randomly assigned to 1 of 5 treatment conditions: iron (20 mg), zinc (20 mg), iron+zinc, MM (16 vitamins and minerals, including iron and zinc), or riboflavin weekly from 6 to 12 mo. Multivariate analyses were conducted to examine the change in development and behavior for each supplementation group, with control for maternal education, HOME score, months breastfed, anemia, growth at 6 mo, and change in growth from 6 to 12 mo.

RESULTS

Iron and zinc administered together and with other micronutrients had a beneficial effect on infant motor development. Iron and zinc administered individually and in combination had a beneficial effect on orientation-engagement. Two-thirds of the infants were mildly anemic, no treatment effects on hemoglobin concentration were observed, and hemoglobin was not associated with measures of development or behavior.

CONCLUSIONS

The beneficial effects of weekly iron and zinc supplementation on motor development and orientation-engagement suggest that infants benefit from these minerals when administered together.

Antiretroviral therapy has changed human immunodeficiency virus (HIV) infection from a near-certainly fatal illness to one that can be managed chronically. More patients are taking antiretroviral drugs (ARVs) for longer periods of time, which naturally results in more observed toxicity. Overdose with ARVs is not commonly reported. The most serious overdose outcomes have been reported in neonates who were inadvertently administered supratherapeutic doses of HIV prophylaxis medications. Typical ARV regimens include a "backbone" of two nucleoside reverse transcriptase inhibitors (NRTI) and a "base" of either a protease inhibitor (PI) or nonnucleoside reverse transcriptase inhibitor. New classes of drugs called entry inhibitors and integrase inhibitors have also emerged. Older NRTIs were associated with mitochondrial toxicity, but this is less common in the newer drugs, emtricitabine, lamivudine, and tenofovir. Mitochondrial toxicity results from NRTI inhibition of a mitochondrial DNA polymerase. Mitochondrial toxicity manifests as myopathy, neuropathy, hepatic failure, and lactic acidosis. Routine lactate assessment in asymptomatic patients is not indicated. Lactate concentration should be obtained in patients taking NRTIs who have fatigue, nausea, vomiting, or vague abdominal pain. Mitochondrial toxicity can be fatal and is treated by supportive care and discontinuing NRTIs. Metabolic cofactors like thiamine, carnitine, and riboflavin may be helpful in managing mitochondrial toxicity. Lipodystrophy describes changes in fat distribution and lipid metabolism that have been attributed to both PIs and NRTIs. Lipodystrophy consists of loss of fat around the face (lipoatrophy), increase in truncal fat, and hypertriglyceridemia. There is no specific treatment of lipodystrophy. Clinicians should be able to recognize effects of chronic toxicity of ARVs, especially mitochondrial toxicity.

One-carbon metabolism is a network of interrelated biochemical reactions that involve the transfer of one-carbon groups from one compound to another. The coenzymes necessary for several of these reactions include the B-vitamins, folate, vitamin B-12, vitamin B-6 and riboflavin (vitamin B-2), whereas important intermediary compounds in this schema include methionine and choline. There has been renewed interest in one-carbon metabolism during the past several years, engendered by recent insights that indicate that modest dietary inadequacies of the abovementioned nutrients, of a degree insufficient to cause classical deficiency syndromes, can still contribute to important diseases such as neural tube defects, cardiovascular disease and cancer. Traditional means of assessing nutrient exposure with food frequency questionnaires, and nutrient status with plasma and urine vitamin assays, has some genuine validity and utility. Assessing the concentration of appropriate intermediary compounds, such as plasma homocysteine for folate and methylmalonic acid for vitamin B-12, provides further insights because they appear to add a degree of sensitivity that does not exist with the more traditional assays. There may also be value in developing measures that integrate the status of all these nutrients and express it as a functional "methylation capacity" of the individual. Plasma or tissue concentrations of S-adenosylmethionine and S-adenosylhomocysteine, and genomic DNA methylation are two potential candidates in this regard although much work is yet to be done to define the nature of these relationships.

Corneal collagen crosslinking (CXL) with riboflavin and ultraviolet-A light is a method for treating progressive keratectasia. The currently accepted treatment parameters induce collagen crosslinking in the anterior 250 to 350 microm of corneal stroma. To protect the endothelium, CXL inclusion criteria require a minimum corneal thickness of 400 microm after removal of the epithelium. In advanced keratoconus, however, progressive corneal thinning often leads to a remaining stromal thickness of less than 400 microm. We have therefore modified the current treatment protocol by preoperatively swelling thin corneas to a stromal thickness of at least 400 microm using hypoosmolar riboflavin solution. This treatment protocol was performed in a case series of 20 patients, and no complications were observed. Preoperative swelling of the cornea safely broadens the spectrum of CXL indications to thin corneas that would otherwise not be eligible for treatment.

Riboflavin (vitamin B(2)) serves as the precursor for FMN and FAD in almost all organisms that utilize the redox-active isoalloxazine ring system as a coenzyme in enzymatic reactions. The role of flavin, however, is not limited to redox processes, as ∼ 10% of flavin-dependent enzymes catalyze nonredox reactions. Moreover, the flavin cofactor is also widely used as a signaling and sensing molecule in biological processes such as phototropism and nitrogen fixation. Here, we present a study of 374 flavin-dependent proteins analyzed with regard to their function, structure and distribution among 22 archaeal, eubacterial, protozoan and eukaryotic genomes. More than 90% of flavin-dependent enzymes are oxidoreductases, and the remaining enzymes are classified as transferases (4.3%), lyases (2.9%), isomerases (1.4%) and ligases (0.4%). The majority of enzymes utilize FAD (75%) rather than FMN (25%), and bind the cofactor noncovalently (90%). High-resolution structures are available for about half of the flavoproteins. FAD-containing proteins predominantly bind the cofactor in a Rossmann fold (∼ 50%), whereas FMN-containing proteins preferably adopt a (βα)(8)-(TIM)-barrel-like or flavodoxin-like fold. The number of genes encoding flavin-dependent proteins varies greatly in the genomes analyzed, and covers a range from ∼ 0.1% to 3.5% of the predicted genes. It appears that some species depend heavily on flavin-dependent oxidoreductases for degradation or biosynthesis, whereas others have minimized their flavoprotein arsenal. An understanding of 'flavin-intensive' lifestyles, such as in the human pathogen Mycobacterium tuberculosis, may result in valuable new intervention strategies that target either riboflavin biosynthesis or uptake.

The Escherichia coli ssuEADCB gene cluster is required for the utilization of alkanesulfonates as sulfur sources, and is expressed under conditions of sulfate or cysteine starvation. The SsuD and SsuE proteins were overexpressed and characterized. SsuE was purified to homogeneity as an N-terminal histidine-tagged fusion protein. Native SsuE was a homodimeric enzyme of M(r) 58,400, which catalyzed an NAD(P)H-dependent reduction of FMN, but it was also able to reduce FAD or riboflavin. The SsuD protein was purified to >98% purity using cation exchange, anion exchange, and hydrophobic interaction chromatography. The pure enzyme catalyzed the conversion of pentanesulfonic acid to sulfite and pentaldehyde and was able to desulfonate a wide range of sulfonated substrates including C-2 to C-10 unsubstituted linear alkanesulfonates, substituted ethanesulfonic acids and sulfonated buffers. SsuD catalysis was absolutely dependent on FMNH(2) and oxygen, and was maximal for SsuE/SsuD molar ratios of 2.1 to 4.2 in 10 mM Tris-HCl, pH 9.1. Native SsuD was a homotetrameric enzyme of M(r) 181,000. These results demonstrate that SsuD is a broad range FMNH(2)-dependent monooxygenase catalyzing the oxygenolytic conversion of alkanesulfonates to sulfite and the corresponding aldehydes. SsuE is the FMN reducing enzyme providing SsuD with FMNH(2).

This review critically examines the relationship between nutritional status and malaria. The data indicate that protein-energy malnutrition is associated with greater malaria morbidity and mortality in humans. In addition, controlled trials of either vitamin A or zinc supplementation show that these nutrients can substantially reduce clinical malaria attacks. Data for iron indicate that supplementation may minimally aggravate certain malariometric indices in some settings and also strongly improve hematologic status. Withholding of iron supplements from deficient population is, therefore, not currently indicated. Available evidence for other nutrients describe varied effects, with some deficiencies being exacerbative (e.g., thiamine), protective (e.g., vitamin E), or both exacerbative and protective in different settings (e.g., riboflavin, vitamin C). The roles of folate, other B vitamins, unsaturated fatty acids, amino acids, and selenium are also examined. Study of the interactions between nutrition and malaria may provide insight to protective mechanisms and result in nutrient-based interventions as low-cost and effective adjuncts to current methods of malaria prevention and treatment.

Animal nutrition is profoundly influenced by the gut microbiota, but knowledge of the scope and core mechanisms of the underlying animal-microbiota interactions is fragmentary. To investigate the nutritional traits shaped by the gut microbiota of Drosophila, we determined the microbiota-dependent response of multiple metabolic and performance indices to systematically varied diet composition. Diet-dependent differences between Drosophila bearing its unmanipulated microbiota (conventional flies) and experimentally deprived of its microbiota (axenic flies) revealed evidence for: microbial sparing of dietary B vitamins, especially riboflavin, on low-yeast diets; microbial promotion of protein nutrition, particularly in females; and microbiota-mediated suppression of lipid/carbohydrate storage, especially on high sugar diets. The microbiota also sets the relationship between energy storage and body mass, indicative of microbial modulation of the host signaling networks that coordinate metabolism with body size. This analysis identifies the multiple impacts of the microbiota on the metabolism of Drosophila, and demonstrates that the significance of these different interactions varies with diet composition and host sex.

We investigated two male infant patients who were given a diagnosis of progressive mitochondrial encephalomyopathy on the basis of clinical, biochemical, and morphological features. These patients were born from monozygotic twin sisters and unrelated fathers, suggesting an X-linked trait. Fibroblasts from both showed reduction of respiratory chain (RC) cIII and cIV, but not of cI activities. We found a disease-segregating mutation in the X-linked AIFM1 gene, encoding the Apoptosis-Inducing Factor (AIF) mitochondrion-associated 1 precursor that deletes arginine 201 (R201 del). Under normal conditions, mature AIF is a FAD-dependent NADH oxidase of unknown function and is targeted to the mitochondrial intermembrane space (this form is called AIF(mit)). Upon apoptogenic stimuli, a soluble form (AIF(sol)) is released by proteolytic cleavage and migrates to the nucleus, where it induces "parthanatos," i.e., caspase-independent fragmentation of chromosomal DNA. In vitro, the AIF(R201 del) mutation decreases stability of both AIF(mit) and AIF(sol) and increases the AIF(sol) DNA binding affinity, a prerequisite for nuclear apoptosis. In AIF(R201 del) fibroblasts, staurosporine-induced parthanatos was markedly increased, whereas re-expression of AIF(wt) induced recovery of RC activities. Numerous TUNEL-positive, caspase 3-negative nuclei were visualized in patient #1's muscle, again indicating markedly increased parthanatos in the AIF(R201 del) critical tissues. We conclude that AIF(R201 del) is an unstable mutant variant associated with increased parthanatos-linked cell death. Our data suggest a role for AIF in RC integrity and mtDNA maintenance, at least in some tissues. Interestingly, riboflavin supplementation was associated with prolonged improvement of patient #1's neurological conditions, as well as correction of RC defects in mutant fibroblasts, suggesting that stabilization of the FAD binding in AIF(mit) is beneficial.

More than 2 million people in the United States have myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). We performed targeted, broad-spectrum metabolomics to gain insights into the biology of CFS. We studied a total of 84 subjects using these methods. Forty-five subjects (n = 22 men and 23 women) met diagnostic criteria for ME/CFS by Institute of Medicine, Canadian, and Fukuda criteria. Thirty-nine subjects (n = 18 men and 21 women) were age- and sex-matched normal controls. Males with CFS were 53 (±2.8) y old (mean ± SEM; range, 21-67 y). Females were 52 (±2.5) y old (range, 20-67 y). The Karnofsky performance scores were 62 (±3.2) for males and 54 (±3.3) for females. We targeted 612 metabolites in plasma from 63 biochemical pathways by hydrophilic interaction liquid chromatography, electrospray ionization, and tandem mass spectrometry in a single-injection method. Patients with CFS showed abnormalities in 20 metabolic pathways. Eighty percent of the diagnostic metabolites were decreased, consistent with a hypometabolic syndrome. Pathway abnormalities included sphingolipid, phospholipid, purine, cholesterol, microbiome, pyrroline-5-carboxylate, riboflavin, branch chain amino acid, peroxisomal, and mitochondrial metabolism. Area under the receiver operator characteristic curve analysis showed diagnostic accuracies of 94% [95% confidence interval (CI), 84-100%] in males using eight metabolites and 96% (95% CI, 86-100%) in females using 13 metabolites. Our data show that despite the heterogeneity of factors leading to CFS, the cellular metabolic response in patients was homogeneous, statistically robust, and chemically similar to the evolutionarily conserved persistence response to environmental stress known as dauer.

BACKGROUND

We previously reported that maternal micronutrient supplementation in rural Nepal decreased low birth weight by approximately 15%.

OBJECTIVE

We examined the effect of daily maternal micronutrient supplementation on fetal loss and infant mortality.

METHODS

The study was a double-blind, cluster-randomized, controlled trial among 4926 pregnant women and their 4130 infants in rural Nepal. In addition to vitamin A (1000 microg retinol equivalents), the intervention groups received either folic acid (FA; 400 microg), FA + iron (60 mg), FA + iron + zinc (30 mg), or multiple micronutrients (MNs; the foregoing plus 10 microg vitamin D, 10 mg vitamin E, 1.6 mg thiamine, 1.8 mg riboflavin, 2.2 mg vitamin B-6, 2.6 microg vitamin B-12, 100 mg vitamin C, 64 microg vitamin K, 20 mg niacin, 2 mg Cu, and 100 mg Mg). The control group received vitamin A only.

RESULTS

None of the supplements reduced fetal loss. Compared with control infants, infants whose mothers received FA alone or with iron or iron + zinc had a consistent pattern of 15-20% lower 3-mo mortality; this pattern was not observed with MNs. The effect on mortality was restricted to preterm infants, among whom the relative risks (RRs) were 0.36 (95% CI: 0.18, 0.75) for FA, 0.53 (0.30, 0.92) for FA + iron, 0.77 (0.45, 1.32) for FA + iron + zinc, and 0.70 (0.41, 1.17) for MNs. Among term infants, the RR for mortality was close to 1 for all supplements except MNs (RR: 1.74; 95% CI: 1.00, 3.04).

CONCLUSIONS

Maternal micronutrient supplementation failed to reduce overall fetal loss or early infant mortality. Among preterm infants, FA alone or with iron reduced mortality in the first 3 mo of life. MNs may increase mortality risk among term infants, but this effect needs further evaluation.

OBJECTIVE

To evaluate the efficacy of ultraviolet-corneal cross-linking (CXL) for treating infectious melting keratitis.

METHODS

Five patients with infectious keratitis associated with corneal melting were treated with CXL at the outpatient departments of the Institut für Refraktive und Ophthalmo-Chirurgie and the eye hospital at the University of Zurich. CXL was performed when the infection did not respond to systemic and topical antibiotic therapy. Follow-up after cross-linking ranged from 1 to 9 months.

RESULTS

In all cases, the progression of corneal melting was halted after CXL treatment. Emergency keratoplasty was not necessary in any of the 5 cases presented.

CONCLUSIONS

CXL is a promising option for treating patients with therapy-refractory infectious keratitis to avoid emergency keratoplasty.

Beaton et al (Am J Clin Nutr 1979;32:2546-59) reported on the partitioning of variance in 1-day dietary data for the intake of energy, protein, total carbohydrate, total fat, classes of fatty acids, cholesterol, and alcohol. Using the same food intake data and the expanded National Heart, Lung and Blood Institute food composition data base, these analyses of sources of variance have been expanded to include classes of carbohydrate, vitamin A, vitamin C, thiamin, riboflavin, niacin, calcium, iron, total ash, caffeine, and crude fiber. The analyses relate to observed intakes (replicated six times) of 30 adult males and 30 adult females obtained under a paired Graeco-Latin square design with sequence of interview, interviewer, and day of the week as determinants. Neither sequence nor interviewer made consistent contribution to variance. In females, day of the week had a significant effect for several nutrients. The major partitioning of variance was between interindividual variation (between subjects) and intraindividual variation (within subjects) which included both true day-to-day variation in intake and methodological variation. For all except caffeine, the intraindividual variability of 1-day data was larger than the interindividual variability. For vitamin A, almost all of the variance was associated with day-to-day variability. One day data provide a very inadequate estimate of usual intake of individuals. In the design of nutrition studies it is critical that the intended use of dietary data be a major consideration in deciding on methodology. There is no "ideal" dietary method. There may be preferred methods for particular purposes.

OBJECTIVE

Postpartum depression (PPD), a major health concern, produces insidious effects on new mothers, their infant, and family. This literature review aims to explore risk factors for postpartum depression among women in Asian cultures, which has not been fully elaborated.

METHODS

A literature search was undertaken by using various electronic research databases. Studies were eligible for this review if they (a) examined risk factors for PPD, (b) were conducted in Asian countries using quantitative or qualitative methodologies, and (c) were published in English in peer-reviewed journals between 1998 and 2008. A total of 64 studies from 17 countries were reviewed, summarised, and synthesised.

RESULTS

The prevalence of postpartum depression in Asian countries ranged from 3.5% to 63.3% where Malaysia and Pakistan had the lowest and highest, respectively. Risk factors for postpartum depression were clustered into five major groups: biological/physical (e.g., riboflavin consumption), psychological (e.g., antenatal depression), obstetric/paediatric (e.g., unwanted pregnancy), socio-demographic (e.g., poverty), and cultural factors (e.g., preference of infants' gender). Traditional postpartum rituals were not found to provide substantial psychological benefits for the new mothers.

CONCLUSIONS

This review informs a current state of knowledge regarding risk factors for postpartum depression and has implications for clinical practice. Health care professionals should be aware that the phenomenon is as prevalent in Asian cultures as in European cultures. Women should be screened for potential risk factors and depressive symptoms during pregnancy and postpartum periods so that appropriate interventions, if needed, can be initiated in a timely fashion.

The B vitamins are water-soluble vitamins required as coenzymes for enzymes essential for cell function. This review focuses on their essential role in maintaining mitochondrial function and on how mitochondria are compromised by a deficiency of any B vitamin. Thiamin (B1) is essential for the oxidative decarboxylation of the multienzyme branched-chain ketoacid dehydrogenase complexes of the citric acid cycle. Riboflavin (B2) is required for the flavoenzymes of the respiratory chain, while NADH is synthesized from niacin (B3) and is required to supply protons for oxidative phosphorylation. Pantothenic acid (B5) is required for coenzyme A formation and is also essential for alpha-ketoglutarate and pyruvate dehydrogenase complexes as well as fatty acid oxidation. Biotin (B7) is the coenzyme of decarboxylases required for gluconeogenesis and fatty acid oxidation. Pyridoxal (B6), folate and cobalamin (B12) properties are reviewed elsewhere in this issue. The experimental animal and clinical evidence that vitamin B therapy alleviates B deficiency symptoms and prevents mitochondrial toxicity is also reviewed. The effectiveness of B vitamins as antioxidants preventing oxidative stress toxicity is also reviewed.

BACKGROUND

Information about nutritional factors as potential risks of orofacial clefts is limited.

METHODS

In this population-based case-control study, we investigated whether periconceptional intakes of supplemental folic acid, dietary folate, and several other nutrients were associated with orofacial clefts. We included data on deliveries from 1997 through 2000 in the National Birth Defects Prevention Study. Orofacial cleft cases were infants or fetuses born with cleft palate (CP) or with cleft lip with or without cleft palate (CLP). Infants without malformations were eligible as controls. Interview participation was 71% among case mothers and 68% among control mothers. Interviews were completed for 704 CLP cases, 404 CP cases, and 2594 controls.

RESULTS

The odds ratio (OR) for CLP associated with use of vitamin supplements containing folic acid was 0.88 (95% confidence interval = 0.73-1.07) and for CP was 1.09 (0.84-1.40). Adjusting for maternal race/ethnicity, age, and education produced an OR of 1.01 (0.82-1.24) for CLP and 1.02 (0.77-1.34) for CP. We found some evidence for decreased CLP risks >>or=30% reduction in risk) with increasing intakes of total protein, choline, and methionine. Decreased CP risk was associated with increased intake of cysteine. Intakes of only 2 micronutrients, iron and riboflavin, were found to reduce CLP risk when adjusted for other nutrients.

CONCLUSIONS

Our observations contribute to the limited body of evidence suggesting a woman's periconceptional diet may influence clefting risks in her offspring. Our finding of no reduction in clefting risk with periconceptional use of supplements containing folic acid is inconsistent with many previous observations but not all.

Chemical riboflavin production, successfully used for decades, is in the course of being replaced by microbial processes. These promise to save half the costs, reduce waste and energy requirements, and use renewable resources like sugar or plant oil. Three microorganisms are currently in use for industrial riboflavin production. The hemiascomycetes Ashbya gossypii, a filamentous fungus, and Candida famata, a yeast, are naturally occurring overproducers of this vitamin. To obtain riboflavin production with the gram-positive bacterium Bacillus subtilis requires at least the deregulation of purine synthesis and a mutation in a flavokinase/FAD-synthetase. It is common to all three organisms that riboflavin production is recognizable by the yellow color of the colonies. This is an important tool for the screening of improved mutants. Antimetabolites like itaconate, which inhibits the isocitrate lyase in A. gossypii, tubercidin, which inhibits purine biosynthesis in C. famata, or roseoflavin, a structural analog of riboflavin used for B. subtilis, have been applied successfully for mutant selections. The production of riboflavin by the two fungi seems to be limited by precursor supply, as was concluded from feeding and gene-overexpression experiments. Although flux studies in B. subtilis revealed an increase both in maintenance metabolism and in the oxidative part of the pentose phosphate pathway, the major limitation there seems to be the riboflavin pathway. Multiple copies of the rib genes and promoter replacements are necessary to achieve competitive productivity.

BACKGROUND

Animal models show that periconceptional supplementation with folic acid, vitamin B-12, choline, and betaine can induce differences in offspring phenotype mediated by epigenetic changes in DNA. In humans, altered DNA methylation patterns have been observed in offspring whose mothers were exposed to famine or who conceived in the Gambian rainy season.

OBJECTIVE

The objective was to understand the seasonality of DNA methylation patterns in rural Gambian women. We studied natural variations in dietary intake of nutrients involved in methyl-donor pathways and their effect on the respective metabolic biomarkers.

METHODS

In 30 women of reproductive age (18-45 y), we monitored diets monthly for 1 y by using 48-h weighed records to measure intakes of choline, betaine, folate, methionine, riboflavin, and vitamins B-6 and B-12. Blood biomarkers of these nutrients, S-adenosylhomocysteine (SAH), S-adenosylmethionine (SAM), homocysteine, cysteine, and dimethylglycine were also assessed monthly.

RESULTS

Dietary intakes of riboflavin, folate, choline, and betaine varied significantly by season; the most dramatic variation was seen for betaine. All metabolic biomarkers showed significant seasonality, and vitamin B-6 and folate had the highest fluctuations. Correlations between dietary intakes and blood biomarkers were found for riboflavin, vitamin B-6, active vitamin B-12 (holotranscobalamin), and betaine. We observed a seasonal switch between the betaine and folate pathways and a probable limiting role of riboflavin in these processes and a higher SAM/SAH ratio during the rainy season.

CONCLUSIONS

Naturally occurring seasonal variations in food-consumption patterns have a profound effect on methyl-donor biomarker status. The direction of these changes was consistent with previously reported differences in methylation of metastable epialleles. This trial was registered at www.clinicaltrials.gov as NCT01811641.

The aim of this review is to summarize the effect in host energy metabolism of the production of B group vitamins and short chain fatty acids (SCFA) by commensal, food-grade and probiotic bacteria, which are also actors of the mammalian nutrition. The mechanisms of how these microbial end products, produced by these bacterial strains, act on energy metabolism will be discussed. We will show that these vitamins and SCFA producing bacteria could be used as tools to recover energy intakes by either optimizing ATP production from foods or by the fermentation of certain fibers in the gastrointestinal tract (GIT). Original data are also presented in this work where SCFA (acetate, butyrate and propionate) and B group vitamins (riboflavin, folate and thiamine) production was determined for selected probiotic bacteria.

OBJECTIVE

To analyze the 10-year results of corneal collagen crosslinking (CXL) for keratoconus.

METHODS

Department of Ophthalmology, University Hospital, Dresden, Germany.

METHODS

Retrospective interventional case series.

METHODS

The study included eyes treated for progressive keratoconus from 2000 to 2004. Corneal collagen crosslinking was performed by applying riboflavin and ultraviolet-A. The corrected distance visual acuity (CDVA), corneal topography, and endothelial cell count (ECC) were recorded preoperatively and 10 years postoperatively.

RESULTS

The study enrolled 24 patients (34 eyes). The mean age of the 18 men and 6 women was 28.4 years ± 7.3 (SD) and the mean follow-up, 131.9 ± 20.1 months. The mean apical keratometry (K) value was 61.5 diopters (D) preoperatively and 55.3 D 10 years postoperatively; the decrease was statistically significant (P<.001). The mean values for maximum K (53.2 D and 49.56 D, respectively) and minimum K (47.5 D and 45.5 D, respectively) were also significantly lower (P<.001). The preoperative and postoperative CDVA were statistically significantly different (P=.002). The mean CDVA improved by 0.14 logMAR over preoperatively; the change was statistically significant (P=.002). The ECC was unchanged.

CONCLUSIONS

Corneal CXL was effective in treating progressive keratoconus, achieving long-term stabilization of the condition. It was easy to perform, had a good safety profile, and reduced the need for corneal transplantation.

BACKGROUND

No author has a financial or proprietary interest in any material or method mentioned.

The multidrug transporter breast cancer resistance protein (BCRP/ABCG2) is strongly induced in the mammary gland during pregnancy and lactation. We here demonstrate that BCRP is responsible for pumping riboflavin (vitamin B(2)) into milk, thus supplying the young with this important nutrient. In Bcrp1(-/-) mice, milk secretion of riboflavin was reduced >60-fold compared to that in wild-type mice. Yet, under laboratory conditions, Bcrp1(-/-) pups showed no riboflavin deficiency due to concomitant milk secretion of its cofactor flavin adenine dinucleotide, which was not affected. Thus, two independent secretion mechanisms supply vitamin B(2) equivalents to milk. BCRP is the first active riboflavin efflux transporter identified in mammals and the first transporter shown to concentrate a vitamin into milk. BCRP activity elsewhere in the body protects against xenotoxins by reducing their absorption and mediating their excretion. Indeed, Bcrp1 activity increased excretion of riboflavin into the intestine and decreased its systemic availability in adult mice. Surprisingly, the paradoxical dual utilization of BCRP as a xenotoxin and a riboflavin pump is evolutionarily conserved among mammals as diverse as mice and humans. This study establishes the principle that an ABC transporter can transport a vitamin into milk and raises the possibility that other vitamins and nutrients are likewise secreted into milk by ABC transporters.