1. Vitamin C and immune function
Ströhle A , Hahn A .
Leibniz Universität Hannover, Institut für Lebensmittelwissenschaft und Okotrophologie, Abteilung Ernährungsphysiologie und Humanernährung, Am Kleinen Felde 30, 30167 Hannover .
Med Monatsschr Pharm. 2009
The immune system is strongly influenced by the intake of nutrients. For a long time there has been a controversy whether vitamin C can contribute to the prevention and therapy of the common cold. Several cells of the immune system can indeed accumulate vitamin C and need the vitamin to perform their task, especially phagocytes and t-cells. Thus a vitamin C deficiency results in a reduced resistance against certain pathogens whilst a higher supply enhances several immune system parameters. With regard to the common cold different studies including meta-analyses underline that the prophylactic intake of vitamin C may slightly reduce the duration of the illness in healthy persons but does not affect its incidence and severity. Supplementation of vitamin C is most effective in cases of physical strain or insufficient intake of the vitamin. With regard to the therapy of the common cold the application of vitamin C alone is without clinical effects.
2.Nutritional deficiencies during normal growth
Suskind DL .
Department of Pediatrics, Division of Pediatric Gastroenterology Hepatology and Nutrition, Seattle Children's Hospital, University of Washington
Pediatr Clin North Am. 2009
Nutritional deficiencies have always been a major consideration in pediatrics. Although the classic forms of many of the well-documented nutritional deficiencies are memorized during training as a physician, nutritional deficiencies that can occur in otherwise asymptomatic normally growing children are often overlooked. The two most common deficiencies seen in children who are growing normally are iron and vitamin D deficiencies. These deficiencies are surprisingly common and can have a significant impact on the overall health of a child. This article reviews these nutritional deficiencies and other less commonly seen deficiencies in children who are otherwise growing normally.
3. Vitamin C requirements in parenteral nutrition
Berger MM .
Service of Adult Intensive Care Medicine and Burns Centre, University Hospital (CHUV), Lausanne , Switzerland
Gastroenterology. 2009
Some biochemical functions of vitamin C make it an essential component of parenteral nutrition (PN) and an important therapeutic supplement in other acute conditions. Ascorbic acid is a strong aqueous antioxidant and is a cofactor for several enzymes. The average body pool of vitamin C is 1.5 g, of which 3%-4% (40-60 mg) is used daily. Steady state is maintained with 60 mg/d in nonsmokers and 140 mg/d in smokers. Shocked surgical, trauma, and septic patients have a drastic reduction of circulating plasma ascorbate concentrations. These low concentrations require 3-g doses/d to restore normal plasma ascorbate concentrations, questioning the recommended PN dose of 100 mg/d. Determination of intravenous requirements is usually based on plasma concentrations, which are altered during the inflammatory response. There is no clear indicator of deficiency: serum or plasma ascorbate concentrations <0.3 mg/dL (20 micromol/L) indicates inadequate vitamin C status. On the basis of available pharmacokinetic data the 100 mg/d dose for patients receiving home PN and 200 mg/d for stable adult patients receiving PN are adequate, but requirements have been shown to be higher in perioperative, trauma, burn, and critically ill patients, paralleling oxidative stress. One recommendation cannot fit all categories of patients. Large vitamin C supplements may be considered in severe critical illness, major trauma, and burns because of increased requirements resulting from oxidative stress and wound healing. Future research should distinguish therapeutic use of high-dose ascorbic acid antioxidant therapy from nutritional PN requirements.
4. Vitamin C in complementary oncology--update 2009
Gröber U .
Akademie & Zentrum für Mikronährstoffmedizin, Zweigertstrasse
Med Monatsschr Pharm. 2009
The antioxidant perhaps most widely used in complementary oncology is vitamin C, particularly by intravenous injection. In light of the recent clinical pharmacokinetic findings, the in vitro evidence of anti-tumour mechanisms and some well-documented cases of advanced cancers the role of high-dose intravenous vitamin C therapy in cancer treatment should be reassessed. High dose intravenous vitamin C therapy may have benefits in patients with advanced cancers, and cancers with poor prognosis and limited therapeutic options, but further clinical studies regarding the safety and efficacy of this therapy are necessary, especially in Germany .
5. Effects of hormone replacement therapy with vitamin C and E supplementation on plasma thyroid hormone levels in postmenopausal women with Type 2 diabetes
Naziroğlu M , Simşek M .
Department of Biophysics, Medical (TIP) Faculty, Süleyman Demirel University , Morfoloji Binasi, TR-32260 Isparta , Turkey
Biomed Pharmacother. 2009
Recent studies have shown that hormone replacement therapy (HRT) can exert regulatory affects on lipid and glucose homeostasis. It has been demonstrated that hyperglycemia also involving the formation of lipid peroxides, exert several biological effects that may contribute to the onset and progression of thyroid and kidney abnormalities of postmenopausal women Type 2 diabetes. Therefore, the aim of our study was to evaluate the effect of HRT, vitamin C and E (VCE) treatments on some plasma biochemical and hematological parameters and plasma thyroid hormone levels in postmenopausal women with or without diabetes. Oral HRT and VCE supplementation were compared with no HRT treatment in 40 non-diabetic postmenopausal women and 40 postmenopausal women with Type 2 diabetes mellitus, in a 6-week randomized prospective study. In the 20 women with diabetes who received oral HRT and the 20 women with diabetes who received HRT plus VCE, there was a significant fall in urea, uric acid, creatinine, total bilirubin, conjugated bilirubin, AST, ALT, LDH values. There was no significant change in red blood cell counts, total protein, albumin, sodium, potassium, hematocrit, hemoglobin and free thyrotoxine and triiodothyronine values in postmenopausal women with diabetes or treated with oral HRT and VCE. In conclusion, daily VCE and HRT administrations seem to produce significant improvement on biochemical parameters in the blood of postmenopausal women with Type 2 diabetes. The HRT and VCE supplementations may strengthen the antioxidant defense system and they may play a role in preventing kidney and liver diseases of postmenopausal women with Type 2 diabetes.
6. Supplementation of vitamin E, vitamin C, and zinc attenuates oxidative stress in burned children: a randomized, double-blind, placebo-controlled pilot study
Barbosa E , Faintuch J , Machado Moreira EA , Gonçalves da Silva VR , Lopes Pereima MJ , Martins Fagundes RL , Filho DW .
Postgraduate Program in Nutrition, Federal University of Santa Catarina
J Burn Care Res. 2009
The aim of this study was to investigate the effect of supplementation of vitamin E, vitamin C, and zinc on the oxidative stress in burned children. In a prospective double-blind placebo controlled pilot study, 32 patients were randomized as no supplementation (n = 15) or antioxidant supplementation (n = 17) groups. Supplementation consisted of the antioxidant mixture of vitamin C (1.5 times upper intake level), vitamin E (1.35 times upper intake level), and zinc (2.0 times recommended dietary allowance) administered during 7 days starting on the second day of admittance into the hospital. Energy requirement was calculated by the Curreri equation, and protein input was 3.0 g/kg of ideal body mass index (percentile 50). Total antioxidant capacity of plasma and malondialdehyde were used to monitor oxidative stress. The time of wound healing was evaluated as the main clinical feature. Patients (age 54.2 +/- 48.9 months, 65.6% males), who exhibited 15.5 +/- 6.7% of total burn area, showed no differences in age and sex, when compared with controls. Intake of the administered antioxidants was obviously higher in treated subjects (P = .005), and serum differences were confirmed for vitamin E and C, but not for zinc (P = .180). There was a decrease in lipid peroxidation (malondialdehyde level) (P = .006) and an increase in vitamin E concentrations in the antioxidant supplementation group (P = .016). The time of wound healing was lower in the supplemented group (P < .001). The antioxidant supplementation through vitamin E and C and the mineral zinc apparently enhanced antioxidant protection against oxidative stress and allowed less time for wound healing.
7. Poor vitamin C status is associated with increased carotid intima-media thickness, decreased microvascular function, and delayed myocardial repolarization in young patients with type 1 diabetes
Odermarsky M , Lykkesfeldt J , Liuba P .
Division of Pediatric Cardiology, Department of Pediatrics, Lund University Hospital , 221 85 Lund , Sweden .
Am J Clin Nutr. 2009
BACKGROUND: Vascular endothelial dysfunction, accelerated thickening of arterial intima, and changes in ventricular repolarization contribute to increased cardiovascular morbidity in type 1 diabetes (T1D). Although vitamin C has important antioxidant functions and increased oxidative stress is a central mechanism of cardiovascular dysfunction in T1D, the relation between vitamin C and the cardiovascular system in young diabetic patients has not been investigated. OBJECTIVE: In a cohort of young patients with T1D, we investigated the relation of plasma concentrations of vitamin C with indexes of vascular function and structure and duration of the QT interval corrected for heart rate (QT(c)). DESIGN: Carotid artery intima-media thickness, cutaneous microvascular function, and duration of the QT(c) interval were measured in 59 patients (mean age: 17 y; range: 10-22 y) with T1D (diabetes duration: 3-20 y). Plasma vitamin C was analyzed by HPLC with coulometric detection. RESULTS: Carotid artery intima-media thickness and duration of the QT(c) interval were higher in patients in the lowest tertile of vitamin C than in those in the highest tertile (P < 0.05 for both). The cutaneous microvascular response to acetylcholine was lower (P = 0.003) in the lowest tertile group than in the highest tertile group, but the response to sodium nitroprusside was not significantly different between these 2 groups. All differences remained significant after adjustment for age, sex, diabetes duration, body mass index, and glycated hemoglobin. CONCLUSIONS: In this relatively small-scale cross-sectional study of young patients with T1D, lower plasma concentrations of vitamin C seem to be associated with adverse changes in the microcirculation, peripheral arteries, and ventricular repolarization. Large-scale prospective studies are needed to confirm these results and to clarify the underlying mechanisms.
8. Nutrition and bone health. Roles of vitamin C and vitamin B as regulators of bone mass and quality
Saito M .
Department of Orthopaedic Surgery, Jikei University School of Medicine.
Vitamin C and a vitamin B are essential nutrients to maintain bone density and bone quality. Recent literature clearly shows that vitamin C and B affect bone quality determinant "collagen cross-link formation" . Mildly elevated plasma homocysteine levels induced by vitamin B insufficiency and methylenetetrahydrofolate reductase (MTHFR) deteriorate normal collagen cross-link formation (Saito M, Osteoporos Int 2009 May 30. [Epub ahead of print] , Shiraki M and Saito M, J Bone Miner Metab [6] 2008) . In this review, we describe the effects of vitamin C and vitamin B insufficiency and hyperhomocysteinemia on bone quality in terms of collagen cross-link formation in bone that have been reported in the literature.
9. Vitamin C function in the brain: vital role of the ascorbate transporter SVCT2
Harrison FE , May JM .
Department of Medicine, Vanderbilt University School of Medicine, Nashville , TN 37232-6303 , USA
Free Radic Biol Med. 2009
Ascorbate (vitamin C) is a vital antioxidant molecule in the brain. However, it also has a number of other important functions, participating as a cofactor in several enzyme reactions, including catecholamine synthesis, collagen production, and regulation of HIF-1 alpha. Ascorbate is transported into the brain and neurons via the sodium-dependent vitamin C transporter 2 (SVCT2), which causes accumulation of ascorbate within cells against a concentration gradient. Dehydroascorbic acid, the oxidized form of ascorbate, is transported via glucose transporters of the GLUT family. Once in cells, it is rapidly reduced to ascorbate. The highest concentrations of ascorbate in the body are found in the brain and in neuroendocrine tissues such as adrenal, although the brain is the most difficult organ to deplete of ascorbate. Combined with regional asymmetry in ascorbate distribution within different brain areas, these facts suggest an important role for ascorbate in the brain. Ascorbate is proposed as a neuromodulator of glutamatergic, dopaminergic, cholinergic, and GABAergic transmission and related behaviors. Neurodegenerative diseases typically involve high levels of oxidative stress and thus ascorbate has been posited to have potential therapeutic roles against ischemic stroke, Alzheimer's disease, Parkinson's disease, and Huntington's disease.
10. Ascorbate transport by primary cultured neurons and its role in neuronal function and protection against excitotoxicity
Qiu S , Li L , Weeber EJ , May JM .
Department Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville , Tennessee , USA
J Neurosci Res. 2007
Neurons maintain relatively high intracellular concentrations of ascorbic acid, which is achieved primarily by the activity of the sodium-dependent vitamin C transporter SVCT2. In this work, we studied the mechanisms by which neuronal cells in culture transport and maintain ascorbate as well as whether this system contributes to maturation of neuronal function and cellular defense against oxidative stress and excitotoxic injury. We found that the SVCT2 helps to maintain high intracellular ascorbate levels, normal ascorbate transport kinetics, and activity-dependent ascorbate recycling. Immunocytochemistry studies revealed that SVCT2 is expressed primarily in the axons of mature hippocampal neurons in culture. In the absence of SVCT2, hippocampal neurons exhibited stunted neurite outgrowth, less glutamate receptor clustering, and reduced spontaneous neuronal activity. Finally, hippocampal cultures from SVCT2-deficient mice showed increased susceptibility to oxidative damage and N-methyl-D-aspartate-induced excitotoxicity. Our results revealed that maintenance of intracellular ascorbate as a result of SVCT2 activity is crucial for neuronal development, functional maturation, and antioxidant responses. (c) 2007 Wiley-Liss, Inc
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