Absorption Of Ascorbic Acid Research Articles

Bioavailability of Liposomal Vitamin C in Powder Form: A Randomized, Double-Blind, Cross-Over Trial

The purpose of this study was to evaluate the properties and pharmacokinetics of liposomal vitamin C in powder form obtained by a method devoid of organic solvents. The powder and liposome morphology were analyzed using scanning electron microscopy (SEM) and cryogenic transmission electron microscopy (cryo-TEM), respectively. Additionally, the carrier particle size, size distribution (STEP-Technology®; L.U.M. GmbH, Berlin, Germany), and zeta potential value were determined. The pharmacokinetic parameters of liposomal and non-liposomal vitamin C (AUC, Cmax, C10h, and C24h) were compared in a randomized, single-dose, double-blind, cross-over trial (ClinicalTrials.gov ID: NCT05843617) involving healthy adult volunteers (n = 10, 1000 mg dose). The process of spray drying used to transform liquid suspensions of the liposomes into powder form did not adversely affect the quality of the carrier particles obtained. Compared to non-encapsulated vitamin C, oral administration of the liposomal formulation resulted in significantly better absorption of ascorbic acid into the bloodstream, which equated to a higher bioavailability of the liposomal product (30% increase in AUC, p < 0.05). The duration of elevated vitamin C blood levels was also longer (C24h increase of 30%, p < 0.05). Although the results obtained are promising and suggest higher bioavailability for the liposomal form of vitamin C, the limited sample size necessitates further research with a larger cohort to confirm these findings.

Exogenous applications of ascorbic acid improve wheat growth, physiology and yield under salinity stress via a balance in antioxidant production and ROS scavenging

ABSTRACT Ascorbic acid (AsA) improves plant tolerance against abiotic stresses, but key mechanisms of salt tolerance by its different application modes are obscure. In this study, 5 mM AsA was applied in seed priming (SP), foliar spray (FS) and medium supplementation (MS) modes to explore their comparative effectiveness in improving salinity (170 mM) tolerance in wheat (Triticum aestivum L. cv. Galaxy-2013). For SP, seeds were primed while FS and MS were administered at tillering. One set of plants was harvested 30 days after treatment to record data for growth, pigments, leaf gas exchange and water relations, as well as shoot and root osmolytes accumulation, antioxidative defence and ionic contents. Another set was harvested at ripening to measure grain yield (GY) components. Salinity stress reduced growth, photosynthesis, water relations, antioxidants defence, enhanced free amino acids, soluble sugars, free proline and glycine betaine, hydrogen peroxide and malondialdehyde. The correlations heatmap revealed positive associations among growth, physiological and GY; being stronger in MS mode. All AsA modes reduced salinity damage, but MS was highly promising. Conclusively, maintenance of a balance in reactive oxygen species dousing and antioxidant production following tissue absorption of AsA in diminishing oxidative damage is a plausible mechanism of wheat salt tolerance.

Higher serum ascorbic acid levels are associated with lower depression prevalence in US adults: a case-control study.

Recent studies have shown that a higher intake of ascorbic acid was associated with a lower prevalence of depression. Nevertheless, the recall bias was common in dietary surveys in these studies, and it was ignored that there were differences in the absorption and utilization of ascorbic acid in the body. Hence, we aim to investigate the association between serum ascorbic acid levels and the prevalence of depression in US adults. A total of 3,404 participants from the 2017-2018 National Health and Nutrition Examination Survey (NHANES) that underwent measurement of the Patient Health Questionnaire-9 (PHQ-9) scores and serum levels of ascorbic acid. Propensity Score Matching (PSM) successfully established a case-control study, comprising 299 participants diagnosed with depression and 1,107 as controls. We used binary logistic regression to estimate odds ratios (ORs) and 95% confidence intervals (CIs) to explore associated risk factors for depression. Restricted cubic splines (RCS) were used to show the nonlinear relationship between serum ascorbic acid levels and the prevalence of depression. The prevalence of depression was approximately 8.8%, with a median serum ascorbic acid level of 49.9 (36.0, 67.0) μmol/L. Results revealed that the serum ascorbic acid levels of depressed patients were significantly lower than those of non-depressed individuals (42.97 VS 52.97 μmol/L). The baseline data indicated that as serum ascorbic acid levels increased from Quartile 1 (Q1) to Quartile 4 (Q4), the depression prevalence decreased from 12.0 to 5.4% (p < 0.05). The results of the chi-square test after PSM showed that serum ascorbic acid was still statistically significant (p < 0.001) with the prevalence of depression. Forest plot showed that compared with the Q1 of serum ascorbic acid level, the OR and 95%CI of depression prevalence in Q4 was 0.42 (0.30 ~ 0.61), and the adjusted OR and 95%CI of depressive prevalence was 0.49 (0.33 ~ 0.73). RCS models showed an L-shaped nonlinear relationship (P for nonlinearity <0.05) between serum ascorbic acid and depression. Our results suggested that higher serum ascorbic acid levels are associated with a reduced prevalence of depression.

Neutral Oil-Incorporated Liposomal Nanocarrier for Increased Skin Delivery of Ascorbic Acid

In this study, a neutral oil-incorporated liposomal system (lipo-oil-some, LOS) was designed to improve the skin absorption of ascorbic acid (Vit C), and the effects of an edge activator and neutral oil on the skin absorption of Vit C were evaluated. As components of the LOS system, sodium deoxycholate, polysorbate 80, and cholesterol were screened as edge activators, and camellia oil, tricaprylin, and grapeseed oil were employed as neutral oils. The LOS systems prepared by the ethanol injection method were spherical in shape, 130-350 nm in size, and had 4-27% Vit C loading efficiency (%). In a skin absorption study using a Franz diffusion cell mounted with porcine skin, the LOS system prepared with sodium deoxycholate (10 w/w% of phospholipid) exhibited 1.2-and 2.9-fold higher absorption than those prepared with polysorbate 80 and cholesterol, respectively. Moreover, the type of neutral oil had a marked effect on the absorption of Vit C; the liposomal system containing camellia oil provided 1.3 to 1.8 times higher flux (45.4 μg/cm2∙h) than vesicles with tricaprylin or grapeseed oil, respectively. The optimized lipid nanocarrier is expected to be a promising tool for promoting the skin absorption of Vit C and improving its dermatological functions.

Salmonella Typhimurium Infection Reduces the Ascorbic Acid Uptake in the Intestine.

Salmonella Typhimurium infection of the gastrointestinal tract leads to damage that compromises the integrity of the intestinal epithelium and results in enterocolitis and inflammation. Salmonella infection promotes the expression of inflammasome NLRP3, leading to activation and release of proinflammatory cytokines such as IL-1β, and the infected host often displays altered nutrient levels. To date, the effect of Salmonella infection and proinflammatory cytokine IL-1β on the intestinal uptake of ascorbic acid (AA) is unknown. Our results revealed a marked decrease in the rate of AA uptake in mouse jejunum infected with Salmonella wild type (WT). However, the nonpathogenic mutant (Δ invA Δ spiB) strain did not affect AA uptake. The decrease in AA uptake due to Salmonella WT infection is accompanied by significantly lower expression of mouse (m)SVCT1 protein, mRNA, and hnRNA levels. NLRP3 and IL-1β expression levels were markedly increased in Salmonella-infected mouse jejunum. IL-1β-exposed Caco-2 cells displayed marked inhibition in AA uptake and significantly decreased hSVCT1 expression at both protein and mRNA levels. Furthermore, the activity of the SLC23A1 promoter was significantly inhibited by IL-1β exposure. In addition, GRHPR (a known SVCT1 interactor) protein and mRNA expression levels were significantly reduced in Salmonella-infected mouse jejunum. These results indicate that Salmonella infection inhibits AA absorption in mouse jejunum and IL-1β-exposed Caco-2 cells. The observed inhibitory effect may partially be mediated through transcriptional mechanisms.

Tailoring Oxygen-Containing Groups on Graphene for Ratiometric Electrochemical Measurements of Ascorbic Acid in Living Subacute Parkinson's Disease Mouse Brains.

Ascorbic acid (AA), a major antioxidant in the central nervous system (CNS), is involved in withstanding oxidative stress that plays a significant role in the pathogenesis of Parkinson's disease (PD). Exploring the AA disturbance in the process of PD is of great value in understanding the molecular mechanism of PD. Herein, by virtue of a carbon fiber electrode (CFE) as a matric electrode, a three-step electrochemical process for tailoring oxygen-containing groups on graphene was well designed: potentiostatic deposition was carried out to fabricate graphene oxide on CFE, electrochemical reduction that assisted in removing the epoxy groups accelerated the electron transfer kinetics of AA oxidation, and electrochemical oxidation that increased the content of the carbonyl group (C═O) generated an inner-reference signal. The mechanism was solidified by ab initio calculations by comparing AA absorption on defected models of graphene functionalized with different oxygen groups including carboxyl, hydroxyl, epoxy, and carbonyl. It was found that epoxy groups would hinder the physical absorption of AA onto graphene, while other functional groups would be beneficial to it. Biocompatible polyethylenedioxythiophene (PEDOT) was further rationally assembled to improve the antifouling property of graphene. As a result, a new platform for ratiometric electrochemical measurements of AA with high sensitivity, excellent selectivity, and reproducibility was established. In vivo determination of AA levels in different regions of living mouse brains by the proposed method demonstrated that AA decreased remarkably in the hippocampus and cortex of a subacute PD mouse than those of a normal mouse.

Common Pitfalls in the Management of Patients with Micronutrient Deficiency: Keep in Mind the Stomach.

Micronutrient deficiencies are relatively common, in particular iron and cobalamin deficiency, and may potentially lead to life-threatening clinical consequences when not promptly recognized and treated, especially in elderly patients. The stomach plays an important role in the homeostasis of some important hematopoietic micronutrients like iron and cobalamin, and probably in others equally important such as ascorbic acid, calcium, and magnesium. A key role is played by the corpus oxyntic mucosa composed of parietal cells whose main function is gastric acid secretion and intrinsic factor production. Gastric acid secretion is necessary for the digestion and absorption of cobalamin and the absorption of iron, calcium, and probably magnesium, and is also essential for the absorption, secretion, and activation of ascorbic acid. Several pathological conditions such as Helicobacter pylori-related gastritis, corpus atrophic gastritis, as well as antisecretory drugs, and gastric surgery may interfere with the normal functioning of gastric oxyntic mucosa and micronutrients homeostasis. Investigation of the stomach by gastroscopy plus biopsies should always be considered in the management of patients with micronutrient deficiencies. The current review focuses on the physiological and pathophysiological aspects of gastric acid secretion and the role of the stomach in iron, cobalamin, calcium, and magnesium deficiency and ascorbate homeostasis.

Apple juice enhances ascorbic acid absorption and accumulation in ODS rats

Apple juice enhances ascorbic acid absorption and accumulation in ODS rats

EnteropathogenicEscherichia coliInfection Inhibits Intestinal Ascorbic Acid Uptake via Dysregulation of Its Transporter Expression.

Enteropathogenic Escherichia coli (EPEC) infection causes prolonged, watery diarrhea leading to morbidity and mortality. Although EPEC infection impacts nutrient transporter function and expression in intestinal epithelial cells, the effects of EPEC infection on intestinal absorption of ascorbic acid (AA) have not yet been investigated. To investigate the effect of EPEC infection on intestinal AA uptake process and expression of both AA transporters. We used two experimental models: human-derived intestinal epithelial Caco-2 cells and mice. 14C-AA uptake assay, Western blot, RT-qPCR, and promoter assay were performed. EPEC (WT) as well as ΔespF and ΔespG/G2 mutant-infected Caco-2 cells showed markedly inhibited AA uptake, while other mutants (ΔescN, ΔespA, ΔespB, and ΔespD) did not affect AA uptake. Infection also reduced protein and mRNA expression levels for both hSVCT1 and hSVCT2. EPEC-infected mice showed marked inhibitory effect on AA uptake and decreased protein and mRNA expression levels for both mSVCT1 and mSVCT2 in jejunum and colon. MicroRNA regulators of SVCT1 and SVCT2 (miR103a, miR141, and miR200a) were upregulated significantly upon EPEC infection in both Caco-2 and mouse jejunum and colon. In addition, expression of the accessory protein glyoxalate reductase/hydroxypyruvate reductase (GRHPR), which regulates SVCT1 function, was markedly decreased by EPEC infection in both models. These findings suggest that EPEC infection causes inhibition in AA uptake through a multifactorial dysregulation of SVCT1 and SVCT2 expression in intestinal epithelial cells.

Enteropathogenic Escherichia coli (EPEC) infection inhibits intestinal vitamin C transporter function and expression: in vitro and in vivo studies

Enteropathogenic Escherichia coli (EPEC) is a food‐borne pathogen and causes enteric illnesses in children. EPEC infection is often associated with malnutrition of the host, especially in individuals experiencing severe and prolonged infection, and/or in those who are nutritionally compromised. While EPEC infection impacts nutrient transporter function and expression in intestinal epithelial cells, to date the consequences of EPEC infection on intestinal absorption of ascorbic acid (AA) are not known. Therefore, we investigated this issue using human intestinal epithelial Caco‐2 cells (in vitro) and mouse (in vivo) models. Infecting Caco‐2 cells with EPEC (WT) markedly inhibited AA uptake. EPEC mutants (ΔescN, ΔespA, ΔespB and ΔespD) did not affect AA uptake, whereas ΔespF and ΔespG/G2 mutants significantly inhibited AA uptake in Caco‐2 cells. Further, we observed significantly reduced expression of both hSVCT1 and hSVCT2 protein and mRNA levels upon infection. Similarly, infecting mice with EPEC (WT) significantly inhibited AA uptake and also reduced the expression of both mSVCT1 and mSVCT2 protein and mRNA levels in jejunum and colon. Studies have shown that epigenetic mechanisms (microRNA) play a role in mediating responses to bacterial infection in the intestine. Therefore, we determined miR103a, miR141 and miR200a expression levels, which were recently shown to regulate SVCT1 and SVCT2. Data from in vitro and in vivo models showed that all three microRNAs were up‐regulated significantly upon EPEC infection. In addition, expression of the accessory protein human glyoxalate reductase/hydroxypyruvate reductase (hGRHPR), which regulates the SVCT1 function, was also markedly decreased by EPEC in both models. These findings suggest that in intestinal epithelial cells, EPEC infection markedly inhibits AA uptake via dysregulation of both SVCT1 and SVCT2 expression.Support or Funding InformationSupported by NIH grants DK 107474, DK 58057, DK 56057, MH108154, GM088790, and a grant from the DVA

Manganese(II)-doped zinc/germanium oxide nanoparticles as a viable fluorescent probe for visual and time-resolved fluorometric determination of ascorbic acid and its oxidase.

A method is described for the determination of ascorbic acid (AA) in complex biological fluids. It based on maganese(II)-doped zinc/germanium oxide nanoparticles (Mn@ZnGe NPs) with appealing time-resolved phosphorescence (TRP). TRP can provide a background-free reporter signalin analytical methods. The absorption of AA overlaps the excitation band of Mn@ZnGe NPs at 254nm. This reduces the intensity of fluorescence via an inner filter effect (IFE) with increasing concentration of AA. Typical experimental conditions include an emission peak at 536nm, a delay time of 50μs and a counting time of 2ms. This method can detect AA in a range of 5-500μM with a 0.13μM limit of detection. If AA is oxidized by the enzymeAA oxidase (AAOx), dehydroascorbic acid will be formed which doesn't absorb at 254nm. Hence, the IFE cannot occur and fluorescence is not reduced. The strategy can be used to quantify AAOx in the activity range of 1-4U·mL-1. By using a handheld UV lamp and a smart phone with a color-scanning feature, the feasibility for visual detection and real-time/onsite quantitative scanometric monitoring of AA and AAOx is demonstrated. Graphical abstract Schematic presentation of a fluorometric method for determination of ascorbic acid (AA) and ascorbic oxidase and a scanometric visual assay. It based on theuse of maganese(II)-doped zinc/germanium oxide nanoparticles (Mn@ZnGe NPs) with appealing time-resolved phosphorescence (TRP) and the inner-filter effect (IFE) between AA and Mn@ZnGe NPs.

MicroRNA-103a regulates sodium-dependent vitamin C transporter-1 expression in intestinal epithelial cells

Intestinal absorption of ascorbic acid (AA) occurs via a Na+-dependent carrier-mediated process facilitated through the human sodium-dependent vitamin C transporters-1 &-2 (hSVCT1 and hSVCT2). Many studies have shown that hSVCT1 (product of the SLC23A1 gene) is expressed on the apical membrane of polarized enterocytes where it mediates AA absorption. hSVCT1 expression levels are therefore an important determinant of physiological vitamin C homeostasis. However, little is known about posttranscriptional mechanisms that regulate hSVCT1 expression in intestinal epithelia. In this study, we investigated regulation of hSVCT1 by microRNA (miRNA). A pmirGLO-SLC23A1–3′-UTR construct transfected into human intestinal cell lines (Caco-2 and NCM460 cells) showed markedly reduced luciferase activity. Bioinformatic analysis of the SLC23A1–3′-UTR predicted five miRNA binding sites (miR-103a, miR-107, miR-328, miR-384, and miR-499-5p) in the 3′-UTR. Expression of mature miR-103a was markedly higher compared to the other four putative miRNA regulators in both intestinal cell lines and mouse jejunal mucosa. Addition of a miR-103a mimic, but not a miR-103a mutant construct, markedly reduced the luminescence of the pmirGLO-SLC23A1–3′-UTR reporter. Reciprocally, addition of a miR-103a inhibitor significantly increased luciferase reporter activity. Addition of the miR-103a mimic led to a significant inhibition in AA uptake, associated with decreased hSVCT1 mRNA and protein expression in Caco-2 cells. In contrast, the miR-103a inhibitor increased AA uptake, associated with increased levels of hSVCT1 mRNA and protein. These findings provide the first evidence for posttranscriptional regulation of hSVCT1 by miRNA in intestinal epithelial cells.

Molecular mechanism(s) involved in differential expression of vitamin C transporters along the intestinal tract.

Mammalian cells utilize two transporters for the uptake of ascorbic acid (AA), Na+-dependent vitamin C transporter SVCT-1 and SVCT-2. In the intestine, these transporters are involved in AA absorption and are expressed at the apical and basolateral membrane domains of the polarized epithelia, respectively. Little is known about the differential expression of these two transporters along the anterior-posterior axis of the intestinal tract and the molecular mechanism(s) that dictate this pattern of expression. We used mouse and human intestinal cDNAs to address these issues. The results showed a significantly lower rate of carrier-mediated AA uptake by mouse colon than jejunum. This was associated with a significantly lower level of expression of SVCT-1 and SVCT-2 at the protein, mRNA, and heterogeneous nuclear RNA (hnRNA) levels in the colon than the jejunum, implying the involvement of transcriptional mechanism(s). Similarly, expression levels of SVCT-1 and SVCT-2 mRNA and hnRNA were significantly lower in human colon. We also examined the levels of expression of hepatocyte nuclear factor 1α and specificity protein 1, which drive transcription of the Slc23a1 and Slc23a2 promoters, respectively, and found them to be markedly lower in the colon. Furthermore, significantly lower levels of the activating markers for histone (H3) modifications [H3 trimethylation of lysine 4 (H3K4me3) and H3 triacetylation of lysine 9 (H3K9ac)] were observed in the Slc23a1 and Slc23a2 promoters in the colon. These findings show, for the first time, that SVCT-1 and SVCT-2 are differentially expressed along the intestinal tract and that this pattern of expression is, at least in part, mediated via transcriptional/epigenetic mechanisms.NEW & NOTEWORTHY Our findings show, for the first time, that transporters of the water-soluble vitamin ascorbic acid (i.e., the vitamin C transporters SVCT-1 and SVCT-2) are differentially expressed along the length of the intestinal tract and that the pattern of expression is mediated, at least in part, by transcriptional and epigenetic mechanism(s) affecting both Slc23a1 and Slc23a2 genes.

Impulsive mathematical modeling of ascorbic acid metabolism in healthy subjects

In this work, we develop an impulsive mathematical model of Vitamin C (ascorbic acid) metabolism in healthy subjects for daily intake over a long period of time. The model includes the dynamics of ascorbic acid plasma concentration, the ascorbic acid absorption in the intestines and a novel approach to quantify the glomerular excretion of ascorbic acid. We investigate qualitative and quantitative dynamics. We show the existence and uniqueness of the global asymptotic stability of the periodic solution. We also perform a numerical simulation for the entire time period based on published data reporting parameters reflecting ascorbic acid metabolism at different oral doses of ascorbic acid.

Formulation and Evaluation of Novel Starch-Based Microspheres for Adsorption of Ascorbic Acid

The microspheres(SBM) was prepared using N, N'-methylene-bis-acrylamide (MBAA) as cross-linker and K2S2O8-Na2SO3 as initiator in water-in-oil emulsion. And then the effects of the O/W ratio (v/v), the amount of cross-linker and the amount of K2S2O8-Na2SO3 on particle size and swelling ratio were investigated. An increase in particle size was observed by increasing the amount of cross-linker and the amount of K2S2O8-Na2SO3, while with decreasing the O/W ratio and the amount of K2S2O8-Na2SO3 particle size was found to decreased, which was just opposite to the trend of swelling ratio. Particle size of the microspheres is 12-65μm. Ascorbic acid was selected as a sample drug, and the function between ascorbic acid and SBM was illustrated by the three-electrode equipment. The absorption mechanism suggested that the absorption of ascorbic acid on SBM is exist and ascribes to hydrogen bond for－OH and－NH2 of SBM and －OH of ascorbic acid.

Vitamin C and Charcot–Marie–Tooth 1A: Pharmacokinetic considerations

Charcot–Marie–Tooth 1A disease (CMT1A) is a disease for which no drug treatments are available. In 2004, it was reported that ascorbic acid reduced the severity of neuropathy in transgenic mice overexpressing PMP22, an animal model of human CMT1A, compared with untreated mice. Based on those results, clinical trials were undertaken at different centers worldwide and four of them have been completed, but none of them resulted in significant improvements. Based on the pharmacokinetics of ascorbic acid, we propose that the randomized clinical trial carried out thus far confirmed the tight control of ascorbic acid's absorption and proved its tolerability at one and two years. The pharmacokinetic considerations discussed in this article might largely explain the disappointing results of the recent CMT1A trials.

Penetration Enhancing Effect of Polysorbate 20 and 80 on the &lt;i&gt;In Vitro&lt;/i&gt; Percutaneous Absorption of LAscorbic Acid

Purpose: To investigate the penetration enhancing effect of two polysorbates - polyoxyethylene 20 (POE-20) and polyoxyethylene 80 (POE-80) - on the in vitro percutaneous absorption of ascorbic acid (AA). Methods: For the permeation experiments, Franz diffusion cell covered with aluminum foil providing an effective diffusion area of 1.76 cm 2 and hairless rabbit skin were used. A range of concentrations (1 – 5 %) of POE-20 and POE-80 was added to the ascorbic acid to determine their optimum enhancement concentration. Results: The cumulative amount of AA that diffused across the skin increased with increase in the concentration of the permeation enhancers. Without the enhancer, AA flux was 0.626 µg/cm 2 /h while mean permeability coefficient (K p) was 2.09 × 10 -6 cm/h. AA flux was 3.17 and 2.44 µg/cm 2 /h for POE-20 and POE-80, respectively, while mean permeability coefficient was 10.6 × 10 -6 and 8.14 × 10 -6 K p, cm/h. Maximum flux (3.16 µg/cm 2 /h) at POE-20 concentration of 5 % was obtained, with an enhancement ratio (ER) of 5.07 in relation to control (i.e., AA without enhancer). For POE-80 (5 %), maximum flux was 2.44 µg/cm 2 /h with an ER value of 3.89, compared to control. Conclusion: This study demonstrates that POE-20 and POE-80 exerted a penetration enhancing effect on the percutaneous absorption of L-ascorbic acid (AA).

Imbalanced dietary ascorbic acid alters molecular pathways involved in skeletogenesis of developing European sea bass ( Dicentrarchus labrax)

The influence of dietary ascorbic acid (AA) on growth and morphogenesis during the larval development of European sea bass ( Dicentrarchus labrax) was evaluated until 45 days post hatching. Diets incorporated 0, 5, 15, 30, 50 or 400 mg AA per kg diet to give AA-0, AA-5, AA-15, AA-30, AA-50 and AA-400 dietary treatments, respectively. Dietary AA levels lower than 15 mg/kg reduced larval growth and survival was affected in specimens fed diets devoid of AA. Globally, disruption of the expression of genes involved in AA and calcium absorption in the intestine (SVCT-1, TRPV-6), skeletogenesis (BMP-4, IGF-1, RARγ) and bone mineralization (VDRβ, osteocalcin) were observed in groups fed doses lower and higher than 50 mg AA/kg diet. Such disturbances detected at molecular level were associated with disruptions of the ossification process and the appearance of skeletal abnormalities.

Absorption and Excretion of Ascorbic Acid Alone and in Acerola (Malpighia emarginata) Juice: Comparison in Healthy Japanese Subjects

It has been suggested that some food components, such as bioflavonoids, affect the bioavailability of ascorbic acid in humans. Since little is known in Japan about the effective intake of this dietary requirement, we tested young Japanese males after the ingestion of commercial ascorbic acid or acerola (Malpighia emarginata DC.) juice to compare the quantities absorbed and excreted. Healthy Japanese subjects received a single oral dose of ascorbic acid solution (50, 100, 200 or 500 mg) and received distilled water as a reference at intervals of 14 d or longer. All subjects were collected blood and urine until 6 h after ingestion and evaluated for time-dependent changes in plasma and urinary ascorbic acid levels. Predictably, the area under the curve (AUC) values in plasma and urine after ingestion increased dose-dependently. Next, each subject received diluted acerola juice containing 50 mg ascorbic acid. Likewise, their plasma and urinary ascorbic acid concentrations were measured. In plasma, the AUC value of ascorbic acid after ingestion of acerola juice tended to be higher than that from ascorbic acid alone. In contrast, the urinary excretion of ascorbic acid at 1, 2 and 5 h after ingestion of acerola juice were significantly less than that of ascorbic acid. These results indicate that some component of acerola juice favorably affected the absorption and excretion of ascorbic acid.

Absorption of Folic Acid and Ascorbic Acid from Nutrient Comparable Beverages

One hundred percent fruit juices can help consumers increase the nutrient content of the diet since these beverages can be naturally rich in micronutrients. Micronutrient-fortified low-calorie beverages are an important alternative to those wishing to minimize their calorie intakes. However, little is known about the bioavailability of nutrients from fortified beverages relative to 100% fruit juices. The present study examined the bioavailability of ascorbic acid (AA) and folic acid (FA) in 100% orange juice (OJ) and a low-calorie beverage fortified with these nutrients. In a within-subjects, cross-over design, 12 adult men consumed a 591 mL serving of OJ, a low-calorie beverage fortified with AA and FA, and 1% low fat milk. Participants were aged 20 to 35 y, with body mass indexes between 20 and 30 kg/m(2). Blood plasma concentrations of AA and serum concentrations of FA were assayed by serial blood draws, made at 30 min intervals for 4.5 h. Blood plasma concentration of AA was significantly greater after ingestion of the fortified beverage compared to after OJ ingestion. However, the bioavailability of AA did not significantly differ from that of OJ. Analyses of FA indicated no significant difference between fortified beverage and OJ. Consumption of both vitamin containing beverages led to higher concentrations of AA and FA than the milk control. This study showed that similar levels of AA and FA bioavailability can be attained through ingestion of 100% OJ and a fortified beverage.