scholarly journals APLICAÇÕES CLÍNICAS DA VITAMINA C: UMA BREVE REVISÃO

2021 ◽  
Vol 9 (209) ◽  
pp. 1-15
Author(s):  
Mylena Rafaelle Maciel Guimarães

Vitamin C or ascorbic acid (AA) is extremely important for humans, as it is not metabolized by the human body, it is necessary to ingest it through diet and / or supplementation. AA has several functions in the body, such as enzymatic cofactors, hormone biosynthesis and antioxidant effect. However, research reports indicate that ingesting high doses of AA may pose health risks. Therefore, the descriptive effect of the clinical application of AA was analyzed. A bibliographic review was carried out and divided into two aspects: the historical view, which was published between 1753 and 2012, and another contemporary study was carried out between 1990 and 2017. The research was carried out on the Academic Google, PubMed, Scielo, Portal de Periódicos da Capes and books, using the keywords: vitamin C, ascorbic acid, antioxidants and pro-oxidants. AA supplements are controversial and their antioxidant and pro-oxidant effects have been described. Its effectiveness in preventing and treating diabetes and cancer is questionable. Therefore, excessive AA supplementation can cause a transition from a healthy to a pathological state, triggering pro-oxidant activity. In addition, the optimal intake dose and the limit between beneficial and harmful doses are still controversial. Therefore, vitamin C should be supplemented with caution and prescribed and supervised by the medical team.

2015 ◽  
Vol 16 (2) ◽  
pp. 157-161 ◽  
Author(s):  
Dragan M. Pavlović ◽  
Merdin Š. Markišić ◽  
Aleksandra M. Pavlović

Abstract Vitamins are necessary factors in human development and normal brain function. Vitamin C is a hydrosoluble compound that humans cannot produce; therefore, we are completely dependent on food intake for vitamin C. Ascorbic acid is an important antioxidative agent and is present in high concentrations in neurons and is also crucial for collagen synthesis throughout the body. Ascorbic acid has a role in modulating many essential neurotransmitters, enables neurogenesis in adult brain and protects cells against infection. While SVCT1 enables the absorption of vitamin C in the intestine, SVCT2 is primarily located in the brain. Ascorbate deficiency is classically expressed as scurvy, which is lethal if not treated. However, subclinical deficiencies are probably much more frequent. Potential fields of vitamin C therapy are in neurodegenerative, cerebrovascular and affective diseases, cancer, brain trauma and others. For example, there is some data on its positive effects in Alzheimer’s disease. Various dosing regimes are used, but ascorbate is safe, even in high doses for protracted periods. Better designed studies are needed to elucidate all of the potential therapeutic roles of vitamin C.


2002 ◽  
Vol 87 (2) ◽  
pp. 97-100 ◽  
Author(s):  
Lauren MacDonald ◽  
Alfred E. Thumser ◽  
Paul Sharp

Vitamin C (ascorbic acid) is an essential nutrient that is involved in a number of cellular processes. However, unlike most mammals, man is unable to synthesize vitamin C and it must therefore be acquired from the diet. Absorption of vitamin C is achieved by two transporters, SVCT1 and SVCT2, recently cloned from rat and human kidney. SVCT1 is thought to be the predominant transporter in the intestine. Vitamin C supplements are increasingly common, thus contributing to an increased dietary load, and therefore the aim of the present study was to investigate the effect of high doses of ascorbic acid on SVCT1 expression. Using the Caco-2 TC7 cell model of small intestinal enterocytes, we measured the effects of ascorbic acid (4·5 mg/ml culture medium) on L-[14C]ascorbic acid uptake and SVCT1 expression (determined by reverse transcription-polymerase chain reaction). Ascorbic acid uptake was decreased significantly in Caco-2 TC7 cells exposed to ascorbate for 24 h (-50 %, P<0·0005). Expression of SVCT1 was also significantly reduced by exposure to elevated levels of ascorbate for 24 h (-77 %, P<0·005). Taken together these results suggest that high-dose supplements might not be the most efficient way of increasing the body pool of vitamin C.


Nutrients ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 615
Author(s):  
Martin Doseděl ◽  
Eduard Jirkovský ◽  
Kateřina Macáková ◽  
Lenka Krčmová ◽  
Lenka Javorská ◽  
...  

Vitamin C (L-ascorbic acid) has been known as an antioxidant for most people. However, its physiological role is much larger and encompasses very different processes ranging from facilitation of iron absorption through involvement in hormones and carnitine synthesis for important roles in epigenetic processes. Contrarily, high doses act as a pro-oxidant than an anti-oxidant. This may also be the reason why plasma levels are meticulously regulated on the level of absorption and excretion in the kidney. Interestingly, most cells contain vitamin C in millimolar concentrations, which is much higher than its plasma concentrations, and compared to other vitamins. The role of vitamin C is well demonstrated by miscellaneous symptoms of its absence—scurvy. The only clinically well-documented indication for vitamin C is scurvy. The effects of vitamin C administration on cancer, cardiovascular diseases, and infections are rather minor or even debatable in the general population. Vitamin C is relatively safe, but caution should be given to the administration of high doses, which can cause overt side effects in some susceptible patients (e.g., oxalate renal stones). Lastly, analytical methods for its determination with advantages and pitfalls are also discussed in this review.


2020 ◽  
Vol 11 (SPL4) ◽  
pp. 1405-1409
Author(s):  
Omodamiro O.D ◽  
Ewa-ibe C ◽  
Jimoh M.A ◽  
Ajah O

Free radical-mediated cell damage can be prevented by well-known antioxidant vitamins such as Vitamins E and C, and it has been reported that Paracetamol can cause hepatotoxicity at high doses. This study evaluated the efficacy of the combination of Vitamin C and Vitamin E in the prevention of renal and hepatic cell damage caused by paracetamol toxicity. Twenty-eight male albino rats were grouped into seven of four rats per group. Vitamin C at prophylactic dosage; (200mg, 150mg, 100mg, 50mg, 25mg) and Vitamin E at prophylactic dosage; (500iu, 400iu, 300iu, 200iu, 100iu) were administered orally to the rats in groups 1 through 5, respectively with concomitant administration 1000mg/kg bw of paracetamol twice daily for seven days. Group 6 was administered 1000mg/kg of paracetamol only (untreated), and Group 7 served as the normal control. The results revealed a significantly (P < 0.05) increase in serum ALT, AST, ALP, Urea and Creatinine of the group administered 1000mg/kg of paracetamol only. The prophylactic doses of ascorbic acid and α-tocopherol significantly (P < 0.05) decrease serum ALT, AST, ALP, Urea and Creatinine level compared to the untreated rats. This study validates that co-administration of ascorbic acid and α-tocopherol at the proposed prophylactic dosages could be used in the prevention of renal and hepatic cell damage caused by paracetamol toxicity.


Author(s):  
Mary K Walingo ◽  

Vitamin C, also known as ascorbic acid, abounds in nature and is highly labile. It is a water-soluble vitamin that is lost in large amounts during food processing. It is a vitamin whose prescribed requirement across cultures is not uniform. For example , the prescribed requirement of vitamin C in Great Britain is 30mg/day, while in the U.S.A., it is 60mg/day and 100mg/day in Japan. These variations are unusual and point to the need for further research to establish the acceptable RDAs for diverse populations. The RDA for vitamin C should be more than the amount needed to prevent the occurrence of disease. Vitamin C plays significant functions in the body that enhance its role in the health status of the human body. The biochemical functions of vitamin C include: stimulation of certain enzymes, collagen biosynthesis, hormonal activation, antioxidant, detoxification of histamine, phagocytic functions of leukocytes, formation of nitrosamine, and proline hydroxylation amongst others. These functions are related to the health effects of vitamin C status in an individual. In human health, vitamin C has been associated with reduction of incidence of cancer, blood pressure, immunity, and drug metabolism and urinary hydroxyproline excretion, tissue regeneration. This vitamin is needed for the proper metabolism of drugs in the body through adequate hepatic mixed function oxidase system. Epidemiological data have revealed the preventive and curative role of vitamin C on certain disease conditions in the body though controversies still persist. Vitamin C is effective in protecting against oxidative damage in tissues and also suppresses formation of carcinogens like nitrosamines. There is an inverse relationship with blood pressure and both plasma vitamin C and Vitamin C. Vitamin C has a lowering effect on blood pressure, especially on systolic pressure more than a diastolic pressure. Low levels of plasma vitamin C are associated with stroke and with an increased risk of all cause mortality. Increased consumption of ascorbic acid raises serum ascorbic levels and could decrease the risk of death.


2020 ◽  
pp. 193229682093218
Author(s):  
Brooke M. Katzman ◽  
Brandon R. Kelley ◽  
Gayle R. Deobald ◽  
Nikki K. Myhre ◽  
Sean A. Agger ◽  
...  

The use of high-dose vitamin C in cancer care has offered promising results for some patients. However, the intravenous (IV) doses used for these patients can reach concentrations that interfere with some strip-based glucose meters. We characterized the impact of vitamin C interference, from standard to the very high doses used for some cancer protocols, using three different hospital-use glucose meters. For two of the three devices tested, increasing concentrations of ascorbic acid caused false elevations in the glucose measurements. The third glucose meter did not provide inaccurate results, regardless of the vitamin C concentration present. Rather, above a certain threshold, the device generated error messages and no results could be obtained.


2021 ◽  
Vol 16 (7-8) ◽  
pp. 118-125
Author(s):  
S.M. Chuklin ◽  
S.S. Chuklin

Vitamin C (ascorbic acid) plays an important physiological role in numerous metabolic functions. It is also a cofactor in the synthesis of important substances, in particular catecholamines and vasopressin. A decrease in the level of ascorbic acid has been noted in various diseases, often accompanying the severity of the patient’s state. The aim of this article is to review the current knowledge on the physiological role of vitamin C and the experimental evidences of its use in critically ill surgical patients. The pharmacodynamics of ascorbic acid, the possibility of using high doses of vitamin C are also considered. MEDLINE database on the PubMed platform was used to search for the literature sources with key words: vitamin C, sepsis, shock, trauma, burns.


2021 ◽  
Vol 5 (1) ◽  
pp. 46-50
Author(s):  
MD Ayu Mira Cyntia Dewi

Background: COVID-19 is a new pandemic that has claimed many lives in many countries. This pandemic was caused by the SARSCoV2. Until now, there is no specific antiviral drug or vaccine against Covid-19 for potential therapy in humans. This virus can cause cytokine storms which can worsen symptoms in sufferers due to an imbalance between increased oxidant production and available antioxidants. Vitamin C is an important antioxidant that protects the body from various bad effects of free radicals. At high concentrations vitamin C plays an important role in immunomodulation. This study was conducted to determine the effect of high doses of vitamin C on levels of pro-inflammatory cytokines in Covid-19. Method: This research type is literature study. The population in this study were journals about Covid-19, vitamin C, antioxidants and free radicals, inflammatory reactions due to viral infections with samples taken from indexed journals published from 2015 to 2020. There are also clinical trials of high doses of vitamin C against inflammation in Covid-19 from these journals. Results: The results of the study in a clinical trial conducted on 54 patients enrolled in 3 hospitals given a 1: 1 ratio for high-dose intravenous vitamin C (HDIVC) or placebo administration. The HDIVC group received 12 g of vitamin C / 50 ml every 12 hours for 7 days at a rate of 12 ml / hour, and the placebo group received bacteriostatic water for injection in the same way. HDIVC administration showed a reduction in inflammatory markers compared to placebo. Conclusion: The conclusion of this study shows that high doses of vitamin C play a role in reducing levels of proinflammatory cytokines.


2013 ◽  
Vol 2013 ◽  
pp. 1-2
Author(s):  
Csaba Kovago ◽  
Nora Meggyeshazi ◽  
Gabor Andocs ◽  
Andras Szasz

According to recent investigations, the parenteral application of ascorbic acid (vitamin C) at high doses has significant antitumor activity in in vitro assays. The goal of our experiment was to determine the possible potentiating effect of application of high dose pH-neutralized ascorbic acid to the normal oncothermia treatment method. The NMRI mice were inoculated with C26 murine colon carcinoma cell line subcutaneously at both of their femoral regions and were kept till the tumors reached symmetrically 10 mm in diameter. We created four experimental groups, containing 5 male and 5 female animals in each. Both vitamin-C and oncothermia treatments were applied once; ascorbic acid was applied intra-peritoneally. Oncothermia treatment was applied only to the right limb tumor; the other side will be used as internal control. After the treatment, the animals were sacrificed, and all tumors were removed and analyzed histopathologically. Our main question centers on the comparison of the cell destruction ratio of the various applied treatment regimes, and studies the possible synergy or additive cross-potentiating of the methods. The results of this experiment turned out to be controversial, since the ascorbic acid did not change the remission rate of the allografts and showed no synergy with oncothermia.


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