For the accurate and reliable measurement of ascorbic acid and dehydroascorbic acid, HPLC can be used in combination with electrochemical or ultraviolet detection. Line and Hoffer have reported a method for the determination of vitamin C in plasma.
It can be analysed by HPLC in connection with electrochemical or ultraviolet light detection. Among many analytical methods, spectrophotometric methods are very simple and low-cost. Several studies used the spectrophotometric method for the determination of ascorbic acid.
Other optical methods for vitamin C estimation include spectrophotometrical determination of iodine reacted with ascorbic acid [ 52 ] and chemiluminescence [ 53 ].
A sensitive, simple and low-cost spectrophotometric method was introduced by Kobra and Somayye in The present method was successfully applied to determine the ascorbic acid in food and pharmaceutical samples. The samples were multivitamin tablet, effervescent tablet, vitamin C injection, natural orange juice, orange syrup powdered and commercial orange liquid.
The method is based on the reaction of AgNO 3 with ascorbic acid in the presence of polyvinyl pyrrolidone PVP and slightly basic medium to prepare silver nanoparticles [ 54 ]. Kapur et al. Mohammed and Hazim in reported a UV-spectrophotometric method for the determination of ascorbic acid in fruits and vegetables from hill region with 2,4-dinitrophenylhydrazine [ 56 ]. A new sensitive colorimetric method for the determination of ascorbic acid tablet in aqueous solution was reported by Ahmed and Mohamed in The method is based on the formation of coloured azo dye by diazotization of 2,4-dichloroaniline, followed by azo-coupling reaction between the resulting product and ascorbic acid [ 57 ].
Electrochemical sensing methods are more widely applied as they are simple, sensitive and moderate methods. Ascorbic acid AA , dopamine and catecholamine are important neurotransmitters in the human body. Hence, the low-level detection of ascorbic acid is very important.
All the methods mentioned above involve complicated pretreatment techniques and expensive instruments. Hence, researchers have developed a more simple, sensitive and accurate electrochemical method for the detection of ascorbic acid. Several studies have reported the electrochemical sensing methods for detection of ascorbic acid. Attempts to simplify such methods have resulted in the development of new methods such as the nickel hexacyanoferrate film-modified aluminium electrode [ 58 ] and graphite epoxy electrode [ 59 ].
These methods use specific and modified working electrode systems that are complicated [ 60 ]. These electrochemical methods are widely used to monitor AA metabolites in vivo or in vitro [ 61 , 62 ]. The metallic nickel electrode —6 M , chemiluminometric flow method 5l M [ 64 ], carbon paste mixed electrode 1. Suw et al. In this method, low ascorbic acid concentrations were detected by the square wave stripping voltammetry and a glassy carbon electrode.
The lower detection limit reported as 0. This method can be used to detect biological materials, pharmaceuticals, food and drugs. Many reports are there for the simultaneous electrochemical detection of ascorbic acid in the presence of dopamine and uric acid on the glassy carbon electrode.
From our own group, we have synthesized electrically conducting poly 3,4-ethylenedioxythiophene nanospindles PEDOTSs and used for the electrochemical sensing of ascorbic acid [ 69 ] Figure Cyclic voltammogram of electrochemical sensing of ascorbic acid using a polyaniline-modified platinum electrode [ 70 ]. In another study, our group developed a low-cost electrochemical sensor based on a platinum electrode for ascorbic acid conductive polyaniline-based composite.
This unique low-cost and user-friendly sensor was validated for the nanomolar detection of AA. The lower detection limit for AA was observed at 0. Electrochemical methods have attracted much attention from clinical diagnostic perspectives because of their easy operation, low cost, rapid response, high sensitivity and good selectivity. Vitamin C plays a pivotal role in body-building process and in disease prevention.
The various functions of vitamin C, including the antioxidant activity, formation of protein, tendons, ligaments and blood vessels, for healing wounds and form scar tissue, for repairing and maintaining cartilage, bone, and teeth, and aiding in the absorption of iron, were discussed. This chapter will definitely benefit the students, researchers and technologists globally. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3.
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Built by scientists, for scientists. Our readership spans scientists, professors, researchers, librarians, and students, as well as business professionals. Studies show that low levels of vitamin C lead to problems with the immune system and other illnesses.
Vitamin C deficiency can result in a condition called scurvy. This deficiency is relatively rare in the United States. Some evidence suggests that vitamin C may help lower the risk of heart disease or its complications. One study indicates that people who consume more vitamin C have a lower risk of death from cardiovascular disease.
Other researchers are not convinced that vitamin C alone improves heart health. However, it is clear that eating more fruits and vegetables can help boost the health of the heart by providing a range of vitamins, minerals, antioxidants, and fiber. Vitamin C has an immune-boosting effect that can help the body fight off illnesses, such as the common cold. One study found that vitamin C helped prevent pneumonia and supported tetanus treatment.
Also, findings of an animal study suggest that vitamin C plays a role in reducing lung inflammation that results from the flu.
Vitamin C is an antioxidant, so it can prevent damage caused by free radicals. This may help prevent diseases such as cancer. Investigations into whether vitamin C effectively prevents cancer have yielded mixed findings. However, the results of a few studies have been positive:. Vitamin C-rich foods can be a part of nearly any meal.
The following breakfast, lunch, and dinner ideas can help a person meet their daily requirement. Many people have a glass of orange juice with breakfast, but this is high in sugar. The Nutrition Source Menu. Search for:. For pregnancy and lactation, the amount increases to 85 mg and mg daily, respectively.
Smoking can deplete vitamin C levels in the body, so an additional 35 mg beyond the RDA is suggested for smokers. The UL for vitamin C is mg daily; taking beyond this amount may promote gastrointestinal distress and diarrhea. Only in specific scenarios, such as under medical supervision or in controlled clinical trials, amounts higher than the UL are sometimes used.
Vitamin C absorption and megadosing The intestines have a limited ability to absorb vitamin C. However, adverse effects are possible with intakes greater than mg daily, including reports of diarrhea, increased formation of kidney stones in those with existing kidney disease or history of stones, increased levels of uric acid a risk factor for gout , and increased iron absorption and overload in individuals with hemochromatosis, a hereditary condition causing excessive iron in the blood.
Chronic diseases Although some epidemiological studies that follow large groups of people over time have found a protective effect of higher intakes of vitamin C from food or supplements from cardiovascular disease and certain cancers, other studies have not. Age-related vision diseases Vitamin C has also been theorized to protect from eye diseases like cataracts and macular degeneration. References Carpenter KJ. The history of scurvy and vitamin C.
Cambridge: Cambridge University Press, Pro-oxidant vs. A high concentration of vitamin C may act as a pro-oxidant and generate hydrogen peroxide that has selective toxicity toward cancer cells [ ].
Based on these findings and a few case reports of patients with advanced cancers who had remarkably long survival times following administration of high-dose IV vitamin C, some researchers support reassessment of the use of high-dose IV vitamin C as a drug to treat cancer [ 3 , 47 , 49 , 52 ]. Therefore, individuals undergoing these procedures should consult with their oncologist prior to taking vitamin C or other antioxidant supplements, especially in high doses [ 54 ].
Evidence from many epidemiological studies suggests that high intakes of fruits and vegetables are associated with a reduced risk of cardiovascular disease [ 1 , 55 , 56 ].
This association might be partly attributable to the antioxidant content of these foods because oxidative damage, including oxidative modification of low-density lipoproteins, is a major cause of cardiovascular disease [ 1 , 4 , 56 ]. In addition to its antioxidant properties, vitamin C has been shown to reduce monocyte adherence to the endothelium, improve endothelium-dependent nitric oxide production and vasodilation, and reduce vascular smooth-muscle-cell apoptosis, which prevents plaque instability in atherosclerosis [ 2 , 57 ].
Results from prospective studies examining associations between vitamin C intake and cardiovascular disease risk are conflicting [ 56 ]. In the Nurses' Health Study, a year prospective study involving 85, female nurses, total intake of vitamin C from both dietary and supplemental sources was inversely associated with coronary heart disease risk [ 58 ]. However, intake of vitamin C from diet alone showed no significant associations, suggesting that vitamin C supplement users might be at lower risk of coronary heart disease.
In male physicians participating in the Physicians' Health Study, use of vitamin C supplements for a mean of 5.
The authors of a meta-analysis of prospective cohort studies, including 14 studies reporting on vitamin C for a median follow-up of 10 years, concluded that dietary, but not supplemental, intake of vitamin C is inversely associated with coronary heart disease risk [ 55 ]. Results from most clinical intervention trials have failed to show a beneficial effect of vitamin C supplementation on the primary or secondary prevention of cardiovascular disease.
Other clinical trials have generally examined the effects on cardiovascular disease of supplements combining vitamin C with other antioxidants, such as vitamin E and beta-carotene, making it more difficult to isolate the potential contribution of vitamin C. The SU. The authors of a meta-analysis of randomized controlled trials concluded that antioxidant supplements vitamins C and E and beta-carotene or selenium do not affect the progression of atherosclerosis [ 66 ].
Similarly, a systematic review of vitamin C's effects on the prevention and treatment of cardiovascular disease found that vitamin C did not have favorable effects on cardiovascular disease prevention [ 67 ].
Since then, researchers have published follow-up data from the Linxian trial, a population nutrition intervention trial conducted in China [ 38 ]. Although the Linxian trial data suggest a possible benefit, overall, the findings from most intervention trials do not provide convincing evidence that vitamin C supplements provide protection against cardiovascular disease or reduce its morbidity or mortality.
However, as discussed in the cancer prevention section, clinical trial data for vitamin C are limited by the fact that plasma and tissue concentrations of vitamin C are tightly controlled in humans.
AMD and cataracts are two of the leading causes of vision loss in older individuals. Oxidative stress might contribute to the etiology of both conditions. A population-based cohort study in the Netherlands found that adults aged 55 years or older who had high dietary intakes of vitamin C as well as beta-carotene, zinc, and vitamin E had a reduced risk of AMD [ 68 ]. However, most prospective studies do not support these findings [ 69 ].
The authors of a systematic review and meta-analysis of prospective cohort studies and randomized clinical trials concluded that the current evidence does not support a role for vitamin C and other antioxidants, including antioxidant supplements, in the primary prevention of early AMD [ 70 ]. Although research has not shown that antioxidants play a role in AMD development, some evidence suggests that they might help slow AMD progression [ 71 ].
After an average follow-up period of 6. A follow-up AREDS2 study confirmed the value of this and similar supplement formulations in reducing the progression of AMD over a median follow-up period of 5 years [ 73 ]. High dietary intakes of vitamin C and higher plasma ascorbate concentrations have been associated with a lower risk of cataract formation in some studies [ 2 , 4 ]. In a 5-year prospective cohort study conducted in Japan, higher dietary vitamin C intake was associated with a reduced risk of developing cataracts in a cohort of more than 30, adults aged 45—64 years [ 74 ].
Data from clinical trials are limited. In one study, Chinese adults who took daily supplements of mg vitamin C plus 30 mcg molybdenum for 5 years did not have a significantly lower cataract risk [ 76 ]. Overall, the currently available evidence does not indicate that vitamin C, taken alone or with other antioxidants, affects the risk of developing AMD, although some evidence indicates that the AREDS formulations might slow AMD progression in people at high risk of developing advanced AMD.
Results of subsequent controlled studies have been inconsistent, resulting in confusion and controversy, although public interest in the subject remains high [ 80 , 81 ]. Prophylactic use of vitamin C did not significantly reduce the risk of developing a cold in the general population.
When taken after the onset of cold symptoms, vitamin C did not affect cold duration or symptom severity. The use of vitamin C supplements might shorten the duration of the common cold and ameliorate symptom severity in the general population [ 80 , 83 ], possibly due to the anti-histamine effect of high-dose vitamin C [ 84 ]. However, taking vitamin C after the onset of cold symptoms does not appear to be beneficial [ 81 ].
Vitamin C has low toxicity and is not believed to cause serious adverse effects at high intakes [ 8 ]. The most common complaints are diarrhea, nausea, abdominal cramps, and other gastrointestinal disturbances due to the osmotic effect of unabsorbed vitamin C in the gastrointestinal tract [ 4 , 8 ]. The mechanism for this effect, if real, is not clear and this finding is from a subgroup of patients in an epidemiological study.
No such association has been observed in any other epidemiological study, so the significance of this finding is uncertain. High vitamin C intakes also have the potential to increase urinary oxalate and uric acid excretion, which could contribute to the formation of kidney stones, especially in individuals with renal disorders [ 8 ]. The best evidence that vitamin C contributes to kidney stone formation is in patients with pre-existing hyperoxaluria [ 23 ]. Due to the enhancement of nonheme iron absorption by vitamin C, a theoretical concern is that high vitamin C intakes might cause excess iron absorption.
In healthy individuals, this does not appear to be a concern [ 8 ]. However, in individuals with hereditary hemochromatosis, chronic consumption of high doses of vitamin C could exacerbate iron overload and result in tissue damage [ 4 , 8 ]. Under certain conditions, vitamin C can act as a pro-oxidant, potentially contributing to oxidative damage [ 8 ]. However, other studies have not shown increased oxidative damage or increased cancer risk with high intakes of vitamin C [ 8 , 90 ].
Other reported effects of high intakes of vitamin C include reduced vitamin B12 and copper levels, accelerated metabolism or excretion of ascorbic acid, erosion of dental enamel, and allergic responses [ 8 ]. However, at least some of these conclusions were a consequence of assay artifact, and additional studies have not confirmed these observations [ 8 ].
Long-term intakes of vitamin C above the UL may increase the risk of adverse health effects. The ULs do not apply to individuals receiving vitamin C for medical treatment, but such individuals should be under the care of a physician [ 8 ].
Vitamin C supplements have the potential to interact with several types of medications. A few examples are provided below. Individuals taking these medications on a regular basis should discuss their vitamin C intakes with their healthcare providers. The safety and efficacy of the use of vitamin C and other antioxidants during cancer treatment is controversial [ 53 , 91 , 92 ].
Some data indicate that antioxidants might protect tumor cells from the action of radiation therapy and chemotherapeutic agents, such as cyclophosphamide, chlorambucil, carmustine, busulfan, thiotepa, and doxorubicin [ 54 , 91 , 93 , 94 ].
At least some of these data have been criticized because of poor study design [ 52 ]. However, due to the physiologically tight control of vitamin C, it is unclear whether oral vitamin C supplements could alter vitamin C concentrations enough to produce the suggested effects. Individuals undergoing chemotherapy or radiation should consult with their oncologist prior to taking vitamin C or other antioxidant supplements, especially in high doses [ 54 ]. It is not known whether this interaction occurs with other lipid-altering regimens [ 54 ].
Healthcare providers should monitor lipid levels in individuals taking both statins and antioxidant supplements [ 54 ]. The federal government's Dietary Guidelines for Americans notes that "Because foods provide an array of nutrients and other components that have benefits for health, nutritional needs should be met primarily through foods. In some cases, fortified foods and dietary supplements are useful when it is not possible otherwise to meet needs for one or more nutrients e.
For more information about building a healthy dietary pattern, refer to the Dietary Guidelines for Americans and the U. Department of Agriculture's MyPlate. This fact sheet by the Office of Dietary Supplements ODS provides information that should not take the place of medical advice.
We encourage you to talk to your healthcare providers doctor, registered dietitian, pharmacist, etc. Any mention in this publication of a specific product or service, or recommendation from an organization or professional society, does not represent an endorsement by ODS of that product, service, or expert advice. Updated: March 26, History of changes to this fact sheet. Find ODS on:. Strengthening Knowledge and Understanding of Dietary Supplements.
Health Information Health Information. Vitamin C Fact Sheet for Consumers. New developments and novel therapeutic perspectives for vitamin C. J Nutr ; Toward a new recommended dietary allowance for vitamin C based on antioxidant and health effects in humans.
Am J Clin Nutr ; Ascorbate is an outstanding antioxidant in human blood plasma. Vitamin C function and status in chronic disease. Nutr Clin Care ;
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