Riboflavin intake and status and relationship to anemia

Photosensitized Z-isomerization of (all-E)-carotenoids by a natural sensitizer riboflavin (vitamin B2): Experimental and quantum chemistry studies

Recent studies have shown that the Z-isomers of carotenoids have higher bioavailability and potentially greater biological activity than the naturally predominant all-E-isomers. Therefore, the development of a safe and efficient isomerization method is required. In this study, a riboflavin-mediated photoisomerization technique was established for increasing the Z-isomer ratio of carotenoids. Initially, to understand the riboflavin-mediated photoisomerization characteristics of carotenoids, the effects of the reaction conditions (e.g., riboflavin concentration, photoirradiation wavelength, and solvent type) on the isomerization and degradation of lycopene were studied, and the total Z-isomer ratio was successfully increased by >50 %. Riboflavin-mediated photoisomerization was also observed in other carotenoids, that is, β-carotene, lutein, astaxanthin, and fucoxanthin. Subsequently, the riboflavin-mediated photoisomerization of lycopene was investigated using quantum chemical calculations, which indicated that the isomerization proceeded via triplet-triplet energy transfer (TTET) from excited riboflavin to lycopene.

Harnessing Oxidative Stress to Obtain Natural Riboflavin Secreting Lactic Acid Bacteria for Use in Biofortification

Lactococcus lactis suffers from oxidative stress and riboflavin starvation at elevated temperatures due to dissolved oxygen, which can be relieved partially by exogenously supplied riboflavin. Here we explore whether this phenomenon can be harnessed to obtain riboflavin overproducing mutants. Using a riboflavin auxotrophic L. lactis strain as a riboflavin biosensor, we screened L. lactis cultures that had been exposed to temperature induced oxidative stress for up to one year. Riboflavin secreting mutants could readily be identified, some of which had arisen after just two weeks of exposure to oxidative stress. Whole genome sequencing revealed mutations in the riboswitch, which regulate riboflavin biosynthesis. Riboflavin secretion conferred a significant increase in tolerance to oxidative stress and enabled growth at high temperatures in the presence of dissolved oxygen. It was subsequently demonstrated that vigorous aeration at high temperature (37 °C) could prompt rapid emergence of riboflavin secreting mutants. The protective effect provided by riboflavin against oxidative stress may explain the natural occurrence of lactic acid bacteria (LAB) secreting riboflavin. By optimizing fermentation conditions and eliminating lactate formation, we achieved 64 mg/L riboflavin, the highest reported titer so far for LAB, which indicates great potential for use as a riboflavin fortification agent in food.

Riboflavin for women's health and emerging microbiome strategies

Riboflavin (vitamin B2) is an essential water-soluble vitamin that serves as a precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). FMN and FAD are coenzymes involved in key enzymatic reactions in energy metabolism, biosynthesis, detoxification and electron scavenging pathways. Riboflavin deficiency is prevalent worldwide and impacts women's health due to riboflavin demands linked to urogenital and reproductive health, hormonal fluctuations during the menstrual cycle, pregnancy, and breastfeeding. Innovative functional foods and nutraceuticals are increasingly developed to meet women's riboflavin needs to supplement dietary sources. An emerging and particularly promising strategy is the administration of riboflavin-producing lactic acid bacteria, combining the health benefits of riboflavin with those of probiotics and in situ riboflavin production. Specific taxa of lactobacilli are of particular interest for women, because of the crucial role of Lactobacillus species in the vagina and the documented health effects of other Lactobacillaceae taxa in the gut and on the skin. In this narrative review, we synthesize the underlying molecular mechanisms and clinical benefits of riboflavin intake for women's health, and evaluate the synergistic potential of riboflavin-producing lactobacilli and other microbiota.

Rats exposed to Alternaria toxins in vivo exhibit altered liver activity highlighted by disruptions in riboflavin and acylcarnitine metabolism

Natural toxins produced by Alternaria fungi include the mycotoxins alternariol, tenuazonic acid and altertoxins I and II. Several of these toxins have shown high toxicity even at low levels including genotoxic, mutagenic, and estrogenic effects. However, the metabolic effects of toxin exposure from Alternaria are understudied, especially in the liver as a key target. To gain insight into the impact of Alternaria toxin exposure on the liver metabolome, rats (n = 21) were exposed to either (1) a complex culture extract with defined toxin profiles from Alternaria alternata (50 mg/kg body weight), (2) the isolated, highly genotoxic altertoxin-II (ATX-II) (0.7 mg/kg of body weight) or (3) a solvent control. The complex mixture contained a spectrum of Alternaria toxins including a controlled dose of ATX-II, matching the concentration of the isolated ATX-II. Liver samples were collected after 24 h and analyzed via liquid chromatography-high-resolution mass spectrometry (LC-HRMS). Authentic reference standards (> 100) were used to identify endogenous metabolites and exogenous compounds from the administered exposures in tandem with SWATH-acquired MS/MS data which was used for non-targeted analysis/screening. Screening for metabolites produced by Alternaria revealed several compounds solely isolated in the liver of rats exposed to the complex culture, confirming results from a previously performed targeted biomonitoring study. This included the altersetin and altercrasin A that were tentatively identified. An untargeted metabolomics analysis found upregulation of acylcarnitines in rats receiving the complex Alternaria extract as well as downregulation of riboflavin in rats exposed to both ATX-II and the complex mixture. Taken together, this work provides a mechanistic view of Alternari toxin exposure and new suspect screening insights into hardly characterized Alternaria toxins.

Fluoride induces immunotoxicity by regulating riboflavin transport and metabolism partly through IL-17A in the spleen

The impairment of the immune system by fluoride is a public health concern worldwide, yet the underlying mechanism is unclear. Both riboflavin and IL-17A are closely related to immune function and regulate the testicular toxicity of fluoride. However, whether riboflavin or IL-17A is involved in fluoride-induced immunotoxicity is unknown. Here, we first established a male ICR mouse model by treating mice with sodium fluoride (NaF) (100 mg/L) via the drinking water for 91 days. The results showed that fluoride increased the expression of the proinflammatory factors IL-1β and IL-17A, which led to splenic inflammation and morphological injury. Moreover, the expression levels of the riboflavin transporters SLC52A2 and SLC52A3; the transformation-related enzymes RFK and FLAD1; and the key mitochondrial functional determinants SDH, COX, and ATP in the spleen were measured via real-time PCR, Western blotting, and ELISA. The results revealed that fluoride disrupted riboflavin transport, transformation, metabolism, and mitochondrial function. Furthermore, wild-type (WT) and IL-17A knockout (IL-17A-/-) C57BL/6 J male mice of the same age were treated with NaF (24 mg/kg·bw, equivalent to 100 mg/L) and/or riboflavin sodium phosphate (5 mg/kg·bw) via gavage for 91 days. Similar parameters were evaluated as above. The results confirmed that fluoride increased riboflavin metabolism through RFK but not through FLAD1. Fluoride also affected mitochondrial function and activated neutrophils (marked with Ly6g) and macrophages (marked with CD68) in the spleen. Interestingly, IL-17A partly mediated fluoride-induced riboflavin metabolism disorder and immunotoxicity in the spleen. This work not only reveals a novel toxic mechanism for fluoride but also provides new clues for exploring the physiological function of riboflavin and for diagnosing and treating the toxic effects of fluoride in the environment.

Effects of immersing Japanese quail eggs in various doses of riboflavin on reproductive, growth performance traits, blood indices and economics

This investigation aimed to evaluate the impact of immersion (IM) riboflavin treatment on the hatchability, production efficiency, and carcass characteristics of Japanese quail eggs. A total of 260 eggs of Japanese quail birds were used for hatching and were randomly divided into 4 treatments with 5 replicates (13 eggs/replicate) in a fully randomized design. Hatching eggs were immersed in riboflavin for 2 min before incubation. The experiment treatments were designed as follows: G1 control group with no treatment, G2 treated with 3 g/L vit. B2 (IM), G3 treated with 4 g/L vit. B2 (IM) and G4 were treated with 5 g/L vit. B2 (IM). After hatching, 128 Japanese quail chicks, aged 7 d, were randomly grouped into 4 treatment groups, with 32 birds in each group. When quails were given vitamin B2 via immersion, they demonstrated significant enhancements in live body weight, body weight gain, feed consumption, and feed conversion ratio at different stages compared to the control group. Compared to control and other groups, the carcass parameters of Japanese quails given a 4 g/L immersion solution showed a significant improvement (P < 0.05). Hatchability and fertility (%) were considerably raised by Vit.B2 treatments of 3, 4, and 5g; the group immersed in 5 g/L had the highest percentages compared to the other groups. Furthermore, treated chickens with all concentrations of vitamin B2 had significantly higher blood indices than the controls. During the exploratory phase (1-6 wk) of age, the highest returns were reported in G4 treated with 5g/L vit. B2 (IM). Treating Japanese quail eggs with different dosages of vitamin B2 by immersion may be recommended to improve their productive and reproductive performance, blood indices, carcass traits, and economic efficiency.

Revitalising Riboflavin: Unveiling Its Timeless Significance in Human Physiology and Health

Since the early twentieth century, research on vitamins has revealed their therapeutic potential beyond their role as essential micronutrients. Riboflavin, known as vitamin B2, stands out for its unique characteristics. Despite numerous studies, riboflavin remains vital, with implications for human health. Abundantly present in various foods, riboflavin acts as a coenzyme in numerous enzymatic reactions crucial for human metabolism. Its role in energy production, erythrocyte synthesis, and vitamin metabolism underscores its importance in maintaining homeostasis. The impact of riboflavin extends to neurological function, skin health, and cardiovascular well-being, with adequate levels linked to reduced risks of various ailments. However, inadequate intake or physiological stress can lead to deficiency, a condition that poses serious health risks, including severe complications. This underscores the importance of maintaining sufficient levels of riboflavin for general wellness. The essential role of riboflavin in immune function further emphasises its significance for human health and vitality. This paper examines the diverse effects of riboflavin on health and stresses the importance of maintaining sufficient levels for overall well-being.

Effects of dietary selenium deficiency and supplementation on liver in grazing sheep: insights from transcriptomic and metabolomic analysis

Background

Mineral elements play a crucial role in supporting the life activities and physiological functions of animals. However, numerous studies have revealed that in some geographical areas and certain grazing situations, grazing livestock frequently suffers from mineral element deficiencies due to the loss of mineral elements from grassland forages, such as selenium (Se). To shed fresh light on this issue, this study aims to investigate the impact of dietary Se deficiency and supplementation on the liver of grazing sheep in these challenging conditions.

Method

This study involved 28 grazing Mongolian Wu Ranke sheep with an average body weight of about 32.20 ± 0.37 kg, which were divided into the Se treatment group and the control group. The Se treatment group was fed with the low-Se diet for 60 days and then continued to be fed with the high-Se diet for 41 days. The liver concentration of minerals, transcriptomic analysis, and untargeted metabolomic analysis were conducted to assess the impact of Se deficiency and supplementation on the liver of grazing sheep.

Results

Dietary Se deficiency and supplementation significantly reduced and elevated liver concentration of Se, respectively (p < 0.05). Gene functional enrichment analysis suggested that dietary Se deficiency might impair protein synthesis efficiency, while Se supplementation was found to enhance liver protein synthesis in grazing sheep. AGAP1, ERN1, MAL2, NFIC, and RERG were identified as critical genes through the weighted gene correlation network analysis, the quantitative real-time polymerase chain reaction, and the receiver operating characteristic curve validation that could potentially serve as biomarkers. Metabolomics analysis revealed that dietary Se deficiency significantly reduced the abundance of metabolites such as 5-hydroxytryptamine, while dietary Se supplementation significantly elevated the abundance of metabolites such as 5-hydroxytryptophan (p < 0.05).

Conclusion

Integrative analysis of the transcriptome and metabolome revealed that dietary Se deficiency led to reduced hepatic antioxidant and anti-inflammatory capacity, whereas Se supplementation increased the hepatic antioxidant and anti-inflammatory capacity in grazing Wu Ranke sheep. These findings provide new insights into the effects of dietary Se deficiency and supplementation on the liver of grazing sheep, potentially leading to improved overall health and well-being of grazing livestock.

Strachan's syndrome and riboflavin deficiency

Strachan's syndrome comprises a triad of optic, auditory and painful sensory peripheral neuropathy. It has been recognised since the late 19th century and is presumed to result from nutritional deficiency. Patients present acute or subacutely after a period of systemic illness, weight loss or, most commonly, dietary restriction, especially veganism, which can cause riboflavin (vitamin B2) and vitamin B12 deficiencies. The syndrome is more common in people who are black British and often of Jamaican descent. We describe the clinical phenotype using a typical case example, review other endemic nutritional peripheral neuropathies and discuss the potential benefit of riboflavin as a treatment.

Risk factors for anaemia among women and their young children hospitalised with suspected thiamine deficiency in northern Lao PDR

Anaemia among women and young children remains a major public health concern. This secondary study describes the anaemia prevalence among young hospitalised children and their mothers in northern Lao People's Democratic Republic and explores possible nutritional causes and risk factors for anaemia. Hospitalised children (ages 21 days to <18 months) with clinical symptoms suggestive of thiamine deficiency disorders were eligible along with their mothers. Venous blood was collected for determination of haemoglobin, ferritin, soluble transferrin receptor (sTfR), retinol-binding protein (RBP), erythrocyte glutathione reductase activation coefficient (EGRac), thiamine diphosphate (ThDP) and acute phase proteins. Risk factors for anaemia were modelled using minimally adjusted logistic regression controlling for age. Haemoglobin results were available for 436 women (mean ± SD age 24.7 ± 6.4 years; 1.6% pregnant) and 427 children (4.3 ± 3.5 months; 60.3% male). Anaemia prevalence (Hb < 120 g/L for nonpregnant women and <110 g/L for pregnant women and children) was 30.7% among women and 55.2% among children. In bivariate analyses, biomarkers significantly associated with anaemia in women were ferritin, sTfR, RBP, EGRac and ThDP. Other risk factors for women were lower BMI, mid-upper arm circumference < 23.5 cm, lower education, lower socioeconomic index, food insecurity, Hmong ethnicity, not/rarely having attended antenatal care, not having taken antenatal iron-containing supplements and not meeting minimum dietary diversity. Risk factors for anaemia among children were older age, male sex, stunting, sTfR, ThDP and alpha-1-acid-glycoprotein. Anaemia was common among women and their hospitalised children and was associated with micronutrient deficiencies and socioeconomic, dietary and health care-seeking risk factors, suggesting that multiple strategies are required to prevent anaemia among women and children.

Protocol for measuring erythrocyte glutathione reductase activity coefficient to assess riboflavin status

Riboflavin (vitamin B2) is a component of the co-enzyme flavin adenine dinucleotide (FAD). The activity coefficient of erythrocyte glutathione reductase (EGRAC), a FAD-dependent enzyme, is a biomarker of riboflavin status. Here, we describe a protocol for measuring unstimulated (basal) and FAD-stimulated (activated) erythrocyte glutathione reductase activity to calculate EGRAC. We describe the steps for preparing washed red blood cells and hemolysates; preparing reagents; loading, incubating, and reading the 96-well plate; and calculating the results. For complete details on the use and execution of this protocol, please refer to Hess et al.1.

Nutritional peripheral neuropathies

Nutritional peripheral neuropathies are a global problem, heavily influenced by geopolitical, cultural and socioeconomic factors. Peripheral neuropathy occurs most frequently secondary to B-vitamin deficiencies, which is suspected to increase in years to come due to the popularity of vegan and vegetarian diets and increased use of bariatric surgery.This review will focus on the common B-vitamins for which a causal link to peripheral neuropathy is more established (vitamins B1, B2, B6, B9 and B12). We will review the historical human and animal data on which much of the clinical descriptions of vitamin deficiencies are based and summarise current available tools for accurately diagnosing a nutritional deficiency. We will also review recently described genetic diseases due to pathogenic variants in genes involved in B-vitamin metabolism that have helped to inform the phenotypes and potential causality of certain B-vitamins in peripheral neuropathy (B2 and B9).Endemic outbreaks of peripheral neuropathy over the last two centuries have been linked to food shortages and nutritional deficiency. These include outbreaks in Jamaican sugar plantation workers in the nineteenth century (Strachan's syndrome), World War two prisoners of war, Cuban endemic neuropathy and also Tanzanian endemic optic neuropathy, which remains a significant public health burden today. An improved understanding of lack of which vitamins cause peripheral neuropathy and how to identify specific deficiencies may lead to prevention of significant and irreversible disability in vulnerable populations.

Combination of Chemically Characterized Pomegranate Extract and Hydrophilic Vitamins against Prolonged Fatigue: A Monocentric, Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Prolonged fatigue is associated with non-pathological causes and lacks an established therapeutic approach. The current study is aimed at assessing the efficacy of a new food supplement (Improve™) based on a chemically characterized pomegranate extract and hydro-soluble vitamins (B complex and C). UHPLC-HRMS analysis of pomegranate extract showed the presence of 59 compounds, with gallotannins and ellagitannins being the most abundant phytochemicals. For the clinical study, 58 subjects were randomized into two groups, 1 and 2 (n = 29, each), which received either the food supplement or placebo. The effects of the food supplement against fatigue were assessed via validated questionnaires, recorded at time intervals t0 (at baseline), t1 (after 28 days), t2 (56 days), and t3 (after follow-up) in combination with the analysis of biochemical markers at t0 and t2. Fatigue severity scale (FSS) questionnaire scores were significantly decreased at the t2 and t3 time intervals in subjects treated with the food supplements, while the effect of the food supplement on a 12-Item Short Form Survey (SF-12) was not considerable. Moreover, the food supplement did not significantly affect biochemical parameters associated with fatigue and stress conditions. This study shows that the food supplement tested reduces prolonged fatigue following two months of supplementation in healthy subjects with mild prolonged fatigue.

Riboflavin Intake Inversely Associated with Cardiovascular-Disease Mortality and Interacting with Folate Intake: Findings from the National Health and Nutrition Examination Survey (NHANES) 2005-2016

The association between intakes of riboflavin and mortality has not been examined intensively in general populations. In this study, 10,480 adults in the 2005-2016 National Health and Nutrition Examination Survey (NHANES) were followed-up until 2019 for their vital status. Riboflavin and folate were assessed by two-day 24 h recall. The date and cause of death were obtained from the US Mortality Registry. The risks of all-cause mortality and cardiovascular disease (CVD) mortality were investigated using a Cox regression analysis. During a mean of 8.5 years follow-up, there were 1214 deaths registered (including 373 deaths from CVD and 302 from cancer). Compared to low level (quartile 1, Q1) of riboflavin intake, the hazard ratios (HRs) (95% confidence interval (CI)) for high level (quartile 4, Q4) were 0.53 (0.31-0.90) for CVD mortality and 0.62 (0.48-0.81) for all-cause mortality. The inverse association between riboflavin intake and CVD mortality was only significant among those with a high intake of folate (p for interaction 0.045). Those with a high folate intake (Q4) and low intake of riboflavin (Q1) had the highest risk of CVD mortality (HR 4.38, 95% CI 1.79-10.72), as compared with a high intake of both riboflavin and folate. In conclusion, riboflavin intake was inversely associated with all-cause mortality and CVD mortality, and the association was modified by folate intake.