Evaluation of riboflavin intakes and status of 20-64-year-old adults in South Korea

Wireless and battery-free wearable biosensing of riboflavin in sweat for precision nutrition

Nutrition assessment is crucial for dietary guidance and prevention of malnutrition. Recent endeavors in wearable biochemical sensors have enabled real-time, in situ analysis of nutrients in sweat. However, the monitoring of riboflavin, an indispensable vitamin B involved in energy metabolism, remains challenging due to its trace level and variations in the sweat matrix. Herein, we report a wireless, battery-free, and flexible wearable biosensing system for the in situ monitoring of sweat riboflavin. Highly sensitive and selective electrochemical voltammetric detection is realized based on the synergistic effect of electrodeposited reduced graphene oxide (rGO) and platinum nanoparticles (PtNPs) with a low detection limit of 1.2 nM. The fully integrated system is capable of sweat sampling with the microfluidic patch, real-time riboflavin analysis and pH calibration with the flexible electrode array, as well as wirelessly simultaneous near field communication (NFC) energy harvesting and data transmission with the flexible circuit and a smartphone. On-body human sweat analysis demonstrates high accuracy cross-validated with gold-standard measurements, and reveals a strong correlation between sweat and urine riboflavin levels. The proposed wearable platform opens up attractive possibilities for noninvasive nutrient tracking, providing strong potential for personalized dietary guidance towards precision nutrition.

Mathematical kinetic modelling followed by in vitro and in vivo assays reveal the bifunctional rice GTPCHII/DHBPS enzymes and demonstrate the key roles of OsRibA proteins in the vitamin B2 pathway

BACKGROUND

Riboflavin is the precursor of several cofactors essential for normal physical and cognitive development, but only plants and some microorganisms can produce it. Humans thus rely on their dietary intake, which at a global level is mainly constituted by cereals (> 50%). Understanding the riboflavin biosynthesis players is key for advancing our knowledge on this essential pathway and can hold promise for biofortification strategies in major crop species. In some bacteria and in Arabidopsis, it is known that RibA1 is a bifunctional protein with distinct GTP cyclohydrolase II (GTPCHII) and 3,4-dihydroxy-2-butanone-4-phosphate synthase (DHBPS) domains. Arabidopsis harbors three RibA isoforms, but only one retained its bifunctionality. In rice, however, the identification and characterization of RibA has not yet been described.

RESULTS

Through mathematical kinetic modeling, we identified RibA as the rate-limiting step of riboflavin pathway and by bioinformatic analysis we confirmed that rice RibA proteins carry both domains, DHBPS and GTPCHII. Phylogenetic analysis revealed that OsRibA isoforms 1 and 2 are similar to Arabidopsis bifunctional RibA1. Heterologous expression of OsRibA1 completely restored the growth of the rib3∆ yeast mutant, lacking DHBPS expression, while causing a 60% growth improvement of the rib1∆ mutant, lacking GTPCHII activity. Regarding OsRibA2, its heterologous expression fully complemented GTPCHII activity, and improved rib3∆ growth by 30%. In vitro activity assays confirmed that both OsRibA1 and OsRibA2 proteins carry GTPCHII/DHBPS activities, but that OsRibA1 has higher DHBPS activity. The overexpression of OsRibA1 in rice callus resulted in a 28% increase in riboflavin content.

CONCLUSIONS

Our study elucidates the critical role of RibA in rice riboflavin biosynthesis pathway, establishing it as the rate-limiting step in the pathway. By identifying and characterizing OsRibA1 and OsRibA2, showcasing their GTPCHII and DHBPS activities, we have advanced the understanding of riboflavin biosynthesis in this staple crop. We further demonstrated that OsRibA1 overexpression in rice callus increases its riboflavin content, providing supporting information for bioengineering efforts.

Host-Guest Encapsulation of RIBO with TSC4X: Synthesis, Characterization, and Its Application by Physicochemical and Computational Investigations

In our present work, we synthesized a new encapsulated complex denoted as RIBO-TSC4X, which was derived from an important vitamin riboflavin (RIBO) and p-sulfonatothiacalix[4]arene(TSC4X). The synthesized complex RIBO-TSC4X was then characterized by utilizing several spectroscopic techniques such as ¹H-NMR, FT-IR, PXRD, SEM, and TGA. Job's plot has been employed to show the encapsulation of RIBO (guest) with TSC4X (host) having a 1:1 molar ratio. The molecular association constant of the complex entity (RIBO-TSC4X) was found to be 3116.29 ± 0.17 M^-1, suggesting the formation of a stable complex. The augment in aqueous solubility of the RIBO-TSC4X complex compared to pure RIBO was investigated by UV-vis spectroscopy, and it was viewed that the newly synthesized complex has almost 30 times enhanced solubility over pure RIBO. The enhancement of thermal stability upto 440 °C for the RIBO-TSC4X complex was examined by TG analysis. This research also forecasts RIBO's release behavior in the presence of CT-DNA, and at the same time, BSA binding study was also carried out. The synthesized RIBO-TSC4X complex exhibited comparatively better free radical scavenging activity, thereby minimizing oxidative injury of the cell as evident from a series of antioxidant and anti-lipid peroxidation assay. Furthermore, the RIBO-TSC4X complex showed peroxidase-like biomimetic activity, which is very useful for several enzyme catalyst reactions.

Riboflavin intake and status and relationship to anemia

Riboflavin in its coenzyme forms, flavin mononucleotide and flavin adenine dinucleotide, is essential for multiple redox reactions necessary for energy production, antioxidant protection, and metabolism of other B vitamins, such as niacin, pyridoxine, and folate. Erythrocyte glutathione reductase activity coefficient (EGRac) is a biomarker of riboflavin status; ratios ≥1.40 are commonly interpreted as indicating biochemical deficiency. Most research on riboflavin status comes from low-income countries and rural settings, which reported high rates of riboflavin deficiency and inadequate intake. However, some studies suggest that riboflavin deficiency, based on the functional indicator EGRac, is also of concern in middle- and high-income countries. Biochemical riboflavin deficiency that does not cause clinical symptoms may contribute to anemia, particularly among women and children. Riboflavin enhances iron absorption, and riboflavin deficiency decreases iron mobilization from stores. The current knowledge on riboflavin's role in metabolic processes and its biochemical status is summarized in this review, and the available evidence on the role of riboflavin in anemia among different populations is discussed.

The Prevalence of Vitamin and Mineral Deficiencies and High Levels of Non-Essential Heavy Metals in Saudi Arabian Adults

Although the micronutrient status of a population is of high national priority, as it critically impacts public health, limited data is available for quantifying the micronutrient status in Saudi Arabia. We aimed to provide comprehensive, epidemiological, descriptive data regarding micronutrient levels in Saudi adults. This cross-sectional study included 3432 adults aged ≥18 years (mean age, 37.7 ± 11.7 years; women, 51.2%) across all 13 Saudi administrative regions (March 2019-November 2021). Laboratory data for 14 micronutrients (8 vitamins, 4 minerals, and 2 nonessential heavy metals) were characterized using descriptive analysis. Vitamin D deficiency (64.3%) was the most prevalent, followed by vitamin B2 (44.9%) and A (9.6%) deficiencies. Among minerals, iron deficiency was the most prevalent (23.2%), followed by zinc (15.3%) and copper (8.7%) deficiencies. Most Saudi adults exhibited normal arsenic (99.7%) and mercury (99.9%) levels. Men exhibited significantly higher vitamin B2, B9, and D deficiencies than women, while women exhibited higher vitamin A, B12, iron, and zinc deficiencies than men. Younger adults demonstrated a significantly higher prevalence of vitamin D and iron deficiencies, whereas older adults exhibited a higher prevalence of vitamin B1 and magnesium deficiencies. As micronutrient deficiencies are a public health concern, health policies and programs need to be developed and implemented to address them.

Riboflavin is an antioxidant: a review update

Aerobic organisms need antioxidant defense systems to deal with free radicals which either are produced during aerobic respiration or may have an external origin. Oxidative stress, which is resulted from an imbalance between the production of free radicals and the ability of antioxidant defense mechanism to deactivate them, is involved in the development of many chronic diseases such as cancer, diabetes, CVD and some neurodegenerative diseases. Reinforcing the antioxidant potential of the body has been considered as a strategy that could prevent and manage such conditions. In the previous review article published by British Journal of Nutrition, in 2014, for the first time, we concluded that riboflavin could alleviate oxidative stress. Although riboflavin can serve as a prooxidant when exposed to ultraviolet irradiation, the literature is replete with studies that support its antioxidant properties. Furthermore, recent evidence suggests that riboflavin may have a therapeutic potential in many conditions in which oxidative stress is involved, although the therapeutic efficacy of riboflavin as an antioxidant requires further study under conditions of wellness and clinical disease.

Association of Household Income Level with Vitamin and Mineral Intake

Appropriate nutrient intake is essential for maintaining health and resisting disease. The current study investigated the association between household income quintile and nutrient intake using data from KNHANES 2019. A total of 5088 South Korean adults were analyzed. The estimated average requirement cut-point method, extended to handle participants with intakes higher than the tolerable upper level, was utilized to determine the need for dietary modification. The suitability of overall vitamin, overall mineral, and individual nutrient intake was evaluated by logistic regression analysis. Subgroup analysis was performed on overall mineral intake suitability. None of the individual nutrients had an intake ratio of over 70%, with the ratio being under 30% for some nutrients. The intake of iron, phosphorus, vitamin B9, and vitamin C had a significant upward trend as household income rose. A subgroup analysis revealed sex differences in the trends of overall mineral intake. The results revealed that some nutrients are not consumed appropriately in the Korean population. Furthermore, they suggest that household income is significantly associated with the intake of overall minerals and several individual nutrients. These results suggest that nutritional assistance is required for certain vulnerable groups, and provide supplementary data for appropriate interventions or further research.

Knowledge Gaps in Understanding the Etiology of Anemia in Indonesian Adolescents

BACKGROUND

Anemia is a public health problem among adolescents in Indonesia. Strategies to prevent or treat anemia should be tailored to local conditions, taking into account its specific etiology and prevalence in a given setting and population group.

OBJECTIVE

This review aims to (1) identify and synthesize the current knowledge on the etiology of anemia among adolescents in Indonesia, (2) reveal knowledge gaps in this area, and (3) suggest directions for future research and programmatic work.

METHODS

We systematically searched PubMed, Web of Science, Scopus, Medline, and WorldCat databases for peer-reviewed journal articles to identify which etiological factors were related to anemia among Indonesian adolescents. Research papers were reviewed and included in the review according to inclusion criteria.

RESULTS

Of 13 studies, 8 showed that anemia was associated with iron deficiency; 4 are suggestive of vitamin A deficiency; and 2 of folic acid deficiency. Five studies underscore different etiological determinants for anemia, such as malaria, protein and energy malnutrition, vitamin B2 deficiency, calcium, and vitamin C deficiency. Based on these findings, we developed a framework on knowledge gaps on the etiology of anemia among adolescents in Indonesia, divided in 3 levels of knowledge: (1) significant knowledge gaps, (2) knowledge gaps, and (3) established knowledge.

CONCLUSIONS

The knowledge gaps around the etiology of anemia among Indonesian adolescents are significant. Our framework emphasizes the need for further research across all etiological factors, namely inadequate nutritional intake and absorption, genetic hemoglobin disorders, infection and inflammation, and menstrual disorders.

Dietary Riboflavin Intake and Riboflavin Status in Young Adult Women Living in Metro Vancouver, Canada

BACKGROUND

Nutrition surveys suggest that <10% of Canadian adults have inadequate riboflavin intakes. However, biochemical riboflavin deficiency [erythrocyte glutathione reductase activity coefficient (EGRac) ≥1.40] has been reported in 41% of young adult women living in Metro Vancouver. Canadian Chinese ethnicity comprise >25% of Vancouver's population and are postulated to have poorer riboflavin status than those of European ethnicity because they could be less likely to consume dairy products and fortified wheat.

OBJECTIVES

The objectives of this study were to determine dietary riboflavin intake and food sources, and to assess the association between riboflavin intake and status in young women of European (n = 107) and Chinese (n = 91) ethnicities living in Metro Vancouver, Canada.

METHODS

This was a cross-sectional study conducted in women (aged 19-45 y). Women were healthy, not pregnant or breastfeeding, of European or Chinese ethnicities, and not taking riboflavin-containing supplements for the past 4 mo. Dietary riboflavin intake was assessed using the past-year Diet History Questionnaire II, and riboflavin status (EGRac) was measured in fasting venous blood samples.

RESULTS

Only 7% of participants had dietary riboflavin intakes below the Estimated Average Requirement (0.9 mg/d), but 40% of women had biochemical riboflavin deficiency (EGRac ≥1.40). Although more Canadian women of European ethnicity than Chinese ethnicity had biochemical riboflavin deficiency (46% and 34%; P < 0.001), median dietary riboflavin intake did not differ (1.73 and 1.82 mg/d; P = 0.587). Dairy products and vegetables contributed the most to riboflavin intake. Energy-adjusted dietary riboflavin intake was inversely associated with EGRac (B = -0.04, 95% CI: -0.07, -0.01). However, after further adjustment the relation was not significant.

CONCLUSIONS

Overall, women of reproductive age living in Metro Vancouver, Canada, had a low prevalence of inadequate dietary riboflavin intake despite the high prevalence of apparent biochemical riboflavin deficiency.

Dietary riboflavin deficiency induces ariboflavinosis and esophageal epithelial atrophy in association with modification of gut microbiota in rats

PURPOSE

Riboflavin deficiency causes ariboflavinosis, a common nutritional deficiency disease. The purpose of this study is to investigate the effects of riboflavin deficiency on the important internal organs and its potential mechanisms.

METHODS

Experiment 1, male F344 rats were randomly assigned to R₆ (normal riboflavin, 6 mg/kg) and R₀ (riboflavin-deficient, 0 mg/kg) groups. Experiment 2 rats were assigned to R₆, R_0.6 (0.6 mg/kg) and R_0.06 (0.06 mg/kg) groups. Experiment 3 rats were assigned to R₆ and R₀ → R₆ (riboflavin replenishment) groups. Bacterial communities were analyzed based on 16S rRNA gene sequencing.

RESULTS

Riboflavin deficiency induced ariboflavinosis (R_0.06 46.7%; R₀ 72%) and esophageal epithelial atrophy (R_0.06 40%; R₀ 44%) in rats, while the R₆ group did not display symptoms (P < 0.001, respectively). Esophageal epithelial atrophy occurred simultaneously (R_0.06 66.7%; R₀ 63.6%) with ariboflavinosis or appeared alone (R_0.06 33.3%; R₀ 36.4%). Esophagus is the most vulnerable internal organ. Riboflavin deficiency followed by replenishment (R₀ → R₆) was effective in treating ariboflavinosis (83.3% vs. 0%, P < 0.001) and esophageal epithelial atrophy (66.7% vs. 20%, P = 0.17). Riboflavin deficiency modulated gut microbiota composition. The several key genera (Romboutsia, Turicibacter and Clostridium sensu stricto 1) were strongly correlated with ariboflavinosis and esophageal epithelial atrophy (P < 0.01 or P < 0.05). The potential mechanism is that gut microbiota affects body's xenobiotic biodegradation and metabolism, and genomic instability.

CONCLUSIONS

Riboflavin deficiency induces ariboflavinosis and esophageal epithelial atrophy by modulating the gut microbiota, and offers new Queryinsight into riboflavin deficiency and esophageal lesions.

Dietary riboflavin deficiency induces genomic instability of esophageal squamous cells that is associated with gut microbiota dysbiosis in rats

SCOPE

Epidemiologic evidence suggests that riboflavin (RBF) deficiency is a specific nutritional predisposition for esophageal cancer. The aim of this study is to investigate the potential roles of gut microbiota in esophageal tumorigenesis caused by the RBF deficiency.

METHODS

Male F344 rats were subcutaneously injected with the chemical carcinogen N-nitrosomethylbenzylamine (NMBA, 0.35 mg kg-1). Rats were assigned to 4 groups, denoted as R6 (normal RBF, 6 mg kg-1), R6N (normal RBF combined with NMBA), R6N → R0N (normal RBF conversion to RBF-deficiency), and R0N → R6N (RBF-deficiency conversion to normal RBF). Bacterial communities were analyzed based on high-throughput 16S rRNA gene sequencing. Oxidative DNA damage and double-strand break markers were studied by immunohistochemistry.

RESULTS

The R6N → R0N diet enhanced the incidence of esophageal intraepithelial neoplasia (EIN, 40 weeks 66.7% vs. 25 weeks 16.7%, P < 0.05). RBF deficiency and replenishment modulated the gut microbiota composition. The gut microbiota (e.g. Caulobacteraceae, Sphingomonas and Bradyrhizobium) affected xenobiotic biodegradation and the genomic instability of the host. Furthermore, the RBF deficiency aggravated oxidative DNA damage and DNA double-strand breaks (immunohistochemistry) in the esophageal epithelium, whereas the RBF replenishment had the opposite effect (P < 0.05, respectively).

CONCLUSIONS

RBF deficiency promotes NMBA-induced esophageal tumorigenesis, which is associated with gut microbiota-associated genomic instability, and offers new insights into the role of RBF deficiency in esophageal carcinogenesis.

Decreased plasma riboflavin is associated with poor prognosis, invasion, and metastasis in esophageal squamous cell carcinoma

BACKGROUND

Riboflavin deficiency confers a predisposition for esophageal cancer. The role of plasma riboflavin levels in development and prognosis of individuals with digestive tract inflammation and ulcer (DTIU), digestive tract polyps (DTPs), and ESCC is not well understood.

METHODS

We performed a cross-sectional study, including 177 DTIU, 80 DTP, and 324 ESCC cases, to measure the plasma riboflavin levels among the three populations. Correlation between plasma riboflavin levels (categorized as ≥31.8, 6.5-31.8 and ≤6.5 nmol/L groups) and clinical characteristics, as well as survival of ESCC patients (556 cases) was analyzed.

RESULTS

There was no difference in plasma riboflavin levels between DTIU, DTP, and ESCC cases (P > 0.05). Plasma riboflavin levels were inversely correlated with invasive depth (correlation coefficient = -0.09, P = 0.026) and lymph node metastasis (correlation coefficient = -0.11, P = 0.010) of ESCC, and ESCC patients with low riboflavin levels had poor recurrence-free survival (P = 0.035) and overall survival (P = 0.003). Decreased riboflavin was a prognostic factor for poor overall survival (HR = 1.91, 95% CI = 1.19-3.07, P = 0.007).

CONCLUSIONS

Plasma riboflavin levels in DTIU, DTP, and ESCC patients are similar. Plasma riboflavin levels are associated with the development and prognosis of ESCC.

Dietary patterns related to cardiovascular disease based on reduced rank regression analysis of healthy middle-aged Koreans: data from the community-based Korean Genome and Epidemiology Study (KoGES) cohort

BACKGROUND

Dietary patterns (DPs) provide a comprehensive picture of the foods consumed by an individual.

OBJECTIVES

Using 12-y follow-up data from the Korean Genome Epidemiology Study (KoGES), we determined the associations of DPs with incident cardiovascular disease (CVD) using reduced rank regression (RRR).

METHODS

This study analyzed the data of 7354 CVD-free subjects aged 40-69 y drawn from the community-based KoGES cohort. Based on the daily intake of 26 food groups at baseline, we identified DPs based on retinol, vitamin B-2 (riboflavin), and vitamin B-3 (niacin) intakes using RRR. The effects of the DPs on incident CVD were assessed using HRs with 95% CIs. Furthermore, using a marginal structural model, the association between DPs and incident CVD was evaluated after adjusting for time-varying confounders.

RESULTS

The incidence of CVD during the follow-up period was 3.7 per 1000 person-years (n = 274). The identified DP accounted for 28.99% of the variation in the response variables (i.e., the intake amounts of all 3 nutrients) and was characterized by high intakes of eggs, fish, milk, and dairy products. The effect of DP quintile on incident CVD differed by sex (Pinteraction = 0.03); the highest DP quintile was associated with a protective effect against the development of CVD in women (HR: 0.44; 95% CI: 0.22, 0.89), but not in men (HR: 1.57; 95% CI: 0.82, 3.00), compared with the lowest quintile. Even after adjusting for time-dependent variables, the effect of DP on incident CVD was significant in women (HR: 0.43; 95% CI: 0.22, 0.84), but not in men (HR: 1.49; 95% CI: 0.71, 3.10).

CONCLUSIONS

In this study, we identified DPs related to CVD, and a DP characterized by high intakes of eggs, fish, milk, and dairy products protected against incident CVD in women.

Riboflavin deficiency alters cholesterol homeostasis partly by reducing apolipoprotein B100 synthesis in HepG2 cells

Riboflavin deficiency led to lower blood cholesterol level and higher content of hepatic cholesterol in rats and the mechanisms are not clarified yet. We hypothesized that riboflavin deficiency might alter cholesterol homeostasis via apolipoprotein B100, one of the important proteins in cholesterol transport. To test this hypothesis, HepG2 cells were cultured in riboflavin-deficient media for 4 days to develop riboflavin deficiency. Compared to riboflavin-sufficient cells, the mRNA (0. 37 ± 0.04 vs 1.03 ± 0.29 relative expression level, n = 3) and protein expressions of apolipoprotein B100 (intracellular: 173.7 ± 14.4 vs 254.8 ± 47.2 μg/mg protein; extracellular: 93.8 ± 31.1 vs 161.6 ± 23.9 μg/mg protein; n = 3) were significantly reduced in riboflavin-deficient cells (P < 0.05). Endoplasmic reticulum oxidoreductin 1 and protein disulfide isomerase, two enzymes involved in the oxidative folding of apolipoprotein B100, were also lower remarkably in expression at both mRNA and protein levels. Meanwhile, intracellular cholesterol was increased (256.3 ± 17.1 μM/g protein vs 181.4 ± 23.9 μM/g protein, n = 4) and extracellular cholesterol decreased (110.0 ± 23.2 μM/g protein vs 166.2 ± 34.6 μM/g protein, n = 4) significantly in riboflavin-deficient cells (P < 0.05). Very low-density lipoprotein was also diminished (29.0 ± 6.1 μM/g protein vs 67.0 ± 11.0 μM/g protein, n = 4) in the culture media (P < 0.05). These findings suggest that riboflavin deficiency alters cholesterol homeostasis partly by reducing apolipoprotein B100 synthesis in HepG2 cells.

Riboflavin deficiency affects lipid metabolism partly by reducing apolipoprotein B100 synthesis in rats

Lipid metabolism is dependent on riboflavin status. Apolipoprotein B100 plays an important role in lipids transportation. This study was aimed to investigate the effect of riboflavin status on lipid metabolism and explore its association with apolipoprotein B100 synthesis in vivo. Riboflavin deficiency was developed in rats by feeding riboflavin-deficient diets. Compared to the control rats, the mRNA and protein expressions of apolipoprotein B100 were significantly reduced in riboflavin-deficient rats. Endoplasmic reticulum oxidoreductin 1 (ERO1) and protein disulfide isomerase (PDI), two enzymes involved in the oxidative folding of apolipoprotein B100, were also lowered remarkably in expression at protein level. Meanwhile, total cholesterol and triglyceride levels were decreased in the plasma and increased in the liver of riboflavin-deficient rats. The plasma very low-density lipoprotein cholesterol (VLDL-c) and low-density lipoprotein cholesterol (LDL-c) were also reduced in riboflavin-deficient rats. Our findings demonstrate that riboflavin deficiency affects lipid metabolism partly by reducing apolipoprotein B100 synthesis.

Riboflavin deficiency induces a significant change in proteomic profiles in HepG2 cells

Riboflavin deficiency is widespread in many regions over the world, especially in underdeveloped countries. In this study, we investigated the effects of riboflavin deficiency on protein expression profiles in HepG2 cells in order to provide molecular information for the abnormalities induced by riboflavin deficiency. HepG2 cells were cultured in media containing different concentrations of riboflavin. Changes of cell viability and apoptosis were assessed. A comparative proteomic analysis was performed using a label-free shotgun method with LC-MS/MS to investigate the global changes of proteomic profiles in response to riboflavin deficiency. Immunoblotting test was used to validate the results of proteomic approach. The cell viability and apoptosis tests showed that riboflavin was vital in maintaining the cytoactivity of HepG2 cells. The label-free proteomic analysis revealed that a total of 37 proteins showing differential expression (±2 fold, p < 0.05) were identified after riboflavin deficiency. Bioinformatics analysis indicated that the riboflavin deficiency caused an up-regulation of Parkinson's disease pathway, steroid catabolism, endoplasmic reticulum stress and apoptotic process, while the fatty acid metabolism, tricarboxylic citrate cycle, oxidative phosphorylation and iron metabolism were down-regulated. These findings provide a molecular basis for the elucidation of the effects caused by riboflavin deficiency.

Riboflavin status, MTHFR genotype and blood pressure: current evidence and implications for personalised nutrition

Clinical deficiency of the B-vitamin riboflavin (vitamin B2) is largely confined to developing countries; however accumulating evidence indicates that suboptimal riboflavin status is a widespread problem across the developed world. Few international data are available on riboflavin status as measured by the functional biomarker, erythrocyte glutathione reductase activation coefficient, considered to be the gold standard index. One important role of riboflavin in the form of flavin dinucleotide is as a co-factor for the folate-metabolising enzyme methylenetetrahydrofolate reductase (MTHFR). Homozygosity for the common C677T polymorphism in MTHFR, affecting over 10 % of the UK and Irish populations and up to 32 % of other populations worldwide, has been associated with an increased risk of CVD, and more recently with hypertension. This review will explore available studies reporting riboflavin status worldwide, the interaction of riboflavin with the MTHFR C677T polymorphism and the potential role of riboflavin in personalised nutrition. Evidence is accumulating for a novel role of riboflavin as an important modulator of blood pressure (BP) specifically in individuals with the MTHFR 677TT genotype, with results from a number of recent randomised controlled trials demonstrating that riboflavin supplementation can significantly reduce systolic BP by 5-13 mmHg in these genetically at risk adults. Studies are however required to investigate the BP-lowering effect of riboflavin in different populations and in response to doses higher than 1·6 mg/d. Furthermore, work focusing on the translation of this research to health professionals and patients is also required.