Vitamin C

Synonym(s): acerola, acerola cherry, ascorbic acid, ascorbyl palmitate, calcium ascorbate, calcium threonate, camu camo, Camu Camu Fruit Extract, Esters C, L-threonate, Malpighia glabra, Natural Vitamin C
Nutrient group: Vitamine, Antioxidants

Sources and physiological effects

Dietary sources

While almost all animals are able to synthesize vitamin C themselves, humans depend on an external supply of the water-soluble vitamin. Vitamin C is widespread in both animal and vegetable foods, some of which contain high quantities. In animal foods, adrenal glands and liver provide the highest concentrations of vitamin C. In plant sources, all fresh fruits, fruit juices and vegetables supply plenty of vitamin C. Particularly high amounts of vitamin C are found in acerola cherries, sea buckthorn, peppers, broccoli, green leafy vegetables, kiwi and citrus fruits. Although potatoes do not contain high concentrations of vitamin C, they can make a significant contribution to vitamin C supply due to their high consumption.

Vitamin C is highly sensitive to oxidation. Heat (e.g. cooking), light (e.g. from improper storage), metal ions (e.g. copper pots) and alkaline media (e.g. sodium bicarbonate) are therefore accompanied by partial or complete destruction of the vitamin. Even with gentle meal preparation, losses of around 30 % are to be expected.  

Physiological effects
Antioxidant
  • Protection of cells against oxidative damage by free radicals
  • Recovers oxidatively consumed vitamin E
  • Regeneration of glutathione
Immune system
  • Protection of the phagocyte membrane against oxidative damage
  • Activation of the complement system
Blood vessels
  • Anti-thrombotic and antihypertensive effect by increasing NO bioavailability
Synthesis of collagen
  • Cofactor of fibroblast formation responsible for connective tissue formation
  • Supports the maturation and stability of the cartilage
Iron metabolism
  • Improvement of iron uptake and utilization
Histamine metabolism
  • Promotion of histamine degradation and mast cell stabilization
Adrenal Gland
  • Participation in the physiological stress reaction through biosynthesis of glucocorticoids

EFSA Health Claims

Health claims EFSA opinion
Vitamin C
  • Contributes to a normal collagen formation for a normal function of the blood vessels
  • Contributes to a normal collagen formation for a normal function of the bones
  • Contributes to normal collagen formation for normal cartilage function
  • Contributes to normal collagen formation for normal gum function
  • Contributes to a normal collagen formation for a normal function of the skin
  • Contributes to a normal collagen formation for a normal function of the teeth
  • Contributes to a normal function of the nervous system
  • Contributes to a normal energy metabolism
  • Contributes to normal psychic function
  • Contributes to a normal function of the immune system
  • Helps protect cells from oxidative stress
  • Contributes to the reduction of fatigue and fatigue
  • Contributes to the regeneration of the reduced form of vitamin E

 

Recommended intake

D-A-CH Recommended nutrient intake
  Age Vitamin C (mg/d)
Infants (months)
  0-4 20
  4-12 20
Children (years)
  1-4  20
  4-7  30
  7-10  45
  10-13  65
  13-15  85
Teenagers/adults (years) Women Men
  15-19  90  105
  19-25  95  110
  25-51  95  110
  51-65  95  110
  > 65  95  110
Pregnancy 105
Breast-feeding   125
Smokers w: 135 mg/d; m: 155 mg/d;
Increased need Sports, chronic disease, AIDS/HIV, arthrosis, diabetes mellitus, tumors, kidney disease, osteoporosis, smoking, stress, alcohol abuse, gastritis, chronic gastrointestinal diseases
Special groups at risk of deficiency Smoking, sports, chronic diseases

 

Recommended intake according to food labelling regulations Vitamin C
(=100 % TB marking on label)  80 mg
Nutrient safety  
UL
 
Long-term daily intake, where no adverse
health effects are expected
2000 mg/d
(according to the NIH)
NOAEL
 
Maximum intake, with no observed adverse
effect.
10000 mg (=10 g)
Safety

EFSA has looked at the safety of vitamin C

Detailed information

Antioxidant Vitamin C – Ascorbic Acid – L-Threonate
Vitamin C is a water-soluble antioxidant that can protect the cells from oxidation by free radicals. It is also able to protect other vitamins such as vitamin E or folic acid from oxidation and maintain them in their active form.

The various biochemical forms of vitamin C (ascorbic acid, ascorbates or the fat-soluble ascorbyl palmitate) are all metabolized in a similar way. The ascorbate content is oxidized to dehydroascorbic acid, which in turn is converted into vitamin C metabolites such as L-threonate. These vitamin C metabolites are endogenous substances and familiar to the body. Research shows that L-threonate (a salt of L-threonic acid) improves vitamin C uptake, vitamin C retention and vitamin C activity, a fact that was decisive in the development and patenting of the new raw material Ester C® -. Ester C® is a combination of calcium ascorbate with 0.9% threonate.

Ester C® higher uptake rates, 24-hour retention, better tolerance, fewer urinary stones
The bioavailability of vitamin C decreases with higher intakes of vitamin C. While about 90% is absorbed with an intake of 100 mg, the absorption rate at 1000 mg drops to below 60% (1). For this reason, a daily intake has been recommended for oral supplementation. Due to the presence of calcium L-threonate, vitamin C is absorbed more quickly and, even at higher doses, is better absorbed by the intestine into the bloodstream (2) and better absorbed into the cells and tissue (3), where it is retained for longer. This results in a higher and more even vitamin C level in the tissue than in conventional vitamin C supplements. A clinical study has shown that Ester C® increases vitamin C status in the body and white blood cells up to 24 hours after ingestion (4). In a direct comparison, Ester C® supplementation was more effective in the prevention and treatment of colds than conventional vitamin C (5). The improved gastric tolerance of Ester C® (6) and the reduced risk of urinary stone formation due to reduced urinary oxalate excretion (4) are additional advantages for therapeutic practice. Ester C® has decisive advantages for the patient and the therapist: Ester C® is not acidic and well tolerated by the stomach and the –has a lower risk of urinary stones that are association with high vitamin C supplementation.
Vitamin C – A classic immune support
For colds, timely and sufficiently high vitamin C supplementation can significantly decrease the duration of the disease in adults and children (7). High doses of vitamin C can prevent a decrease in the vitamin C concentration in the leukocytes and thus increase their phagocytosis activity (1). Since Ester C® is retained in the white blood cells in the long term, this vitamin C form ensures 24-hour immune protection (8).
Vitamin C for wound healing
The wound healing process requires the formation and storage of collagen at the injured site. As an essential cofactor in collagen formation, vitamin C is required in these processes and also has an anti-inflammatory effect (9). Patients with wound healing disorders, decubitus, ulcer crusis, burns and after surgery benefit from an adequate vitamin C supply (1), ideally in combination with zinc.
Cardiovascular disorders
A meta-analysis shows that 500 mg vitamin C, taken for at least 4 weeks, can lead to a significant decrease of LDL cholesterol and triglycerides in serum (10). Due to its protective function, vitamin C can also prevent oxidative changes in cholesterol and LDL fractions. In addition, vitamin C appears to have endothelial relaxant properties. . Supportive vitamin C supplementation is therefore useful for patients with atherosclerotic changes and high blood pressure (11).
Cancer
Various epidemiological studies have found a significant correlation between vitamin C intake and the incidence of certain types of cancer. The risk of developing stomach, breast, lung or colon cancer is significantly increased in patients with low vitamin C plasma levels (12). Recent studies have also shown that vitamin C in pharmacological doses can cause apoptosis of certain tumor cells (13).
Vitamin C in diabetes mellitus
Diabetics have significantly reduced vitamin C plasma levels and lower intracellular vitamin C concentrations. The development of late complications such as retino-, nephro- and neuropathies can be linked to this (1). In a study in diabetics, 1 g vitamin C significantly reduced fasting blood sugar, serum insulin, triglyceride levels, LDL and HbA1c, which can reduce the risk of diabetes complications (14). A permanent supplementation of 1 to 3 g vitamin C per day is recommended as an supportive orthomolecular measure for diabetics.
Antioxidant protection for smokers
Smoking is associated with increased oxidative stress and low vitamin C plasma levels (15). Ester C® also shows a retention effect in white blood cells in smokers, thus ensuring 24-hour immune protection (8).
Rutin and quercetin, the natural "vitamin savers";
The bioflavonoids rutin and quercetin have an antioxidant effect on vitamin C, i.e. they recycle oxidized vitamin C and therefore act as “vitamin savers“ and „vitamin enhancers“ (1). In nature, they usually occur in combination, which is why a synergistic effect of these substances has been suspected for a long time. Due to their antioxidant properties, bioflavonoids, like vitamin C, also have anticarcinogenic, immunostimulatory (7) and anti-edemic effects.
Natural vitamin C from fruit extracts of acerola and camu camu

The fruits of the acerola cherry (Malpighia glabra) have an exceptionally high vitamin C content of up to 25%. Compared to oranges, the acerola cherry can contain 30 times as much vitamin C and twice as much magnesium and pantothenic acid. The fruits also contain iron, calcium, phosphorus and vitamins A, vitamin B1, vitamin B2 and niacin. In total, about 150 components were identified in the acerola cherry. In Brazil, the consumption of acerola juice is as common as orange juice consumption in Europe and North America. The fresh fruits are also used as a natural remedy for fever and diarrhea. They have anti-inflammatory, astringent and diuretic effects and are used as a heart tonic and stimulant for the liver and kidney system. Acerola cherry also provides natural support for anemia, diabetes, high cholesterol, liver problems, rheumatism, tuberculosis and during recovery.

The fruits of the tropical camu camu shrub are also characterized by a high vitamin C content, which exceeds that of oranges by a factor of 30 to 50. The red fruits also contain a lot of iron, niacin, vitamin B2, phosphorus, carotenoids and bioflavonoids and thus have antioxidant, astringent and calming effects.

 

Reference values

Parameter Substrate Reference value Description
Vitamin C Serum 4 - 15 mg/l Fasting (12-h)
Vitamin C is extremely sensitive to light and heat. The sample must be centrifuged and stabilized as quickly as possible (after max. 30 minutes).
Interpretation
Low values Indication of vitamin C deficiency, poor nutrition or malnutrition, small bowel disease
High values Practically only observed with parenteral nutrition
Note on the measurement results
As vitamin C is degraded extremely quickly, improper handling of the sample can lead to a false-positive result.
Nutrigenetics
Characteristic gene sites and their effects on vitamin requirements
Gene rsNumber

Risk SNP

Description

Recommended nutrients

TXN

rs2301241

T

Thioredoxin (TXN) plays an important role in the physiological redox system. Due to a reduced efficiency less vitamin C and coenzyme Q10 is recycled. Vitamin E as an important antioxidant can additionally compensate for adverse effects (16).

Vitamin E,
Coenzyme Q10 and Vitamin C

 

Deficiency symptoms

Impact on Symptoms
General health Fatigue, poor performance
Blood Hypochromic, microcytic anemia, thrombocytopenia, granulocytopenia, increased bleeding tendency
Immune system Susceptibility to infection, immunodeficiency
Teeth and gums Periodontopathies, gingivitis, bleeding gums
Oxidative stress Increased risk of free-radical associated sequelae (cancer, diabetic damage, cataract)
Oxidation protection Increased susceptibility to free-radical-associated diseases

Indications

Effect Indication Dosage
Physiological effects
at a low intake
For general prevention 350 - 500 mg/d
To increase vitamin C intake in cases of increased need, e.g. oxidative stress, in smokers and when taking medication  500 - 1000 mg/d
Complementary therapy for cold and flu infections  500 - 2000 mg/d
Complementary therapy for wound healing disorders, burns, decubitus and for connective tissue weaknesses  500 - 1000 mg/d
Pharmacological effects
at a high intake
For therapy support in cardiovascular diseasesarteriosclerosis and diabetes mellitus   500 - 3000 mg/d

 

Administration

General mode of administration
 
When
 
Vitamin C should be taken with meals.
Side effects
In very high doses, mild gastrointestinal disorders (flatulence, diarrhoea) can occur.
Contraindications
Iron storage disease (hemochromatosis), renal insufficiency.
Do not use high doses of oxalate stones (urolithiasis) and hyperoxaluria (>500 mg).

Interactions

Drug interactions
NSAIDs (especially salicylates) Inhibit the active transport of vitamin C through the intestinal wall.
ASA can lower vitamin C levels in the blood and white blood cells.
Vitamin C administration protects against NSAIDs-induced mucous membrane damage.
Corticosteroids (e.g. methylprednisolone) Increased renal vitamin C excretion and increased vitamin C oxidation.
Oral contraceptives Estrogens can increase vitamin C requirements.
Anti Parkinson's drug (L-Dopa) Vitamin C can improve the absorption of L-dopa.
Nitrates (e.g. glycerol trinitrate, isosorbide mononitrate, molsidomin) Vitamin C reduces nitrate tolerance.
Nutrient interactions
Trace elements Vitamin C converts trivalent iron into more absorbable bivalent iron (in high doses).
Long-term high doses of vitamin C can impair copper absorption.
Vitamin C can reduce the absorption of sodium selenite (in high doses).
Vitamins Vitamin C deficiency can increase the excretion of vitamin B6.
Simultaneous intake of vitamin C and vitamin B12 may lead to reduced absorption of vitamin B12.
Secondary plant substances Bioflavonoids increase the bioavailability of vitamin C.

Description and related substances

Description of the micronutrient
Water soluble vitamin
Related substances

Ascorbic acid, various ascorbates are permitted:
L-ascorbic acid, sodium L-ascorbate, calcium L-ascorbate, potassium L-ascorbate, magnesium L-ascorbate, zinc L-ascorbate
the fat-soluble ascorbyl palmitate and Ester-C®.

References

References
1) Gröber Uwe: Orthomolekulare Medizin. Ein Leitfaden für Apotheker und Ärzte. 2008.
2) Verlangieri AJ: An acute study on the relative gastro-intestinal absorption of a novel form of calcium ascorbate. Res Commun Chem Pathol Pharmacol. 1987; 57 (1): 137-40.
3) Verlangieri AJ, Fay MJ, Bannon AW: Comparison of the anti-scorbutic activity of L-ascorbic acid and Ester-C in the non-ascorbate synthesizing Osteogenic Disorder Shionogi (ODS) rat. Life Sci. 1991; 48 (23): 2275-81.
4) Moyad MA et al: Vitamin C with metabolites reduces oxalate levels compared to ascorbic acid: a preliminary and novel clinical urologic finding. Urol Nurs. 2009 Mar-Apr; 29 (2): 95-102.
5) Van Straten M, Josling P: Preventing the common cold with a vitamin C supplement: a double-blind, placebo-controlled survey. Adv Ther. 2002 May- Jun; 19 (3): 151-9.
6) Gruenwald J et al: Safety and tolerance of ester-C compared with regular ascorbic acid. Adv Ther. 2006 Jan-Feb; 23 (1): 171-8.
7) Heimer KA, Hart AM et al.: Examining the evidence for the use of vitamin C in the prophylaxis and treatment of the common cold. J Am Acad Nurse Pract. 2009 May; 21 (5): 295-300.
8) Moyad MA et al: Vitamin C metabolites, independent of smoking status, significantly enhance leukocyte, but not plasma ascorbate concentrations. Adv Ther. 2008 Oct; 25 (10): 995-1009.
9) Lima CC, Pereira AP et al.: Ascorbic acid for the healing of skin wounds in rats. Braz J Biol. 2009 Nov; 69 (4): 1195-201.
10) McRae MP: Vitamin C supplementation lowers serum low-density lipoprotein cholesterol and triglycerides: a meta-analysis of 13 randomized controlled trials. J Chiropr Med. 2008 Jun; 7 (2): 48-58.
11) Hahn Andrea, Ströhle Alexander, Wolters Maike: Ernährung. Physiologische Grundlagen, Prävention, Therapie. 2006.
12) Block G: Vitamin C and cancer prevention: The epidemiologic evidence. Am J Clin Nutr. 1991; 53.
13) Chen Q, Espey MG et al.: Pharmacologic doses of ascorbate act as a prooxidant and decrease growth of aggressive tumor xenografts in mice. Proc Natl Acad Sci U S A. 2008 Aug 12; 105 (32): 11105-9.
14) Afkhami-Ardekani M, Shojaoddiny-Ardekani A.: Effect of vitamin C on blood glucose, serum lipids & serum insulin in type 2 diabetes patients. Indian J Med Res. 2007 Nov; 126 (5): 471-4.
15) Northrop-Clewes CA, Thurnham DI.: Monitoring micronutrients in cigarette smokers. Clin Chim Acta. 2007 Feb; 377 (1-2): 14-38.
16) Mansego, M. L. et al. 2015. The nutrigenetic influence of the interaction between dietary vitamin E and TXN and COMT gene polymorphisms on waist circumference: a case control study. J Transl Med. 13:286. 

References Interactions
Stargrove Mitchell Bebel, Treasure Jonathan, McKee Dwight L.: Herb, Nutrient, and Drug Interactions: Clinical Implications and Therapeutic Strategies. 2008
Gröber Uwe: Mikronährstoffe. Metabolic Tuning – Prävention – Therapie. 3. Auflage, 2011
Gröber Uwe: Arzneimittel und Mikronährstoffe. Medikationsorientierte Supplementierung. 2. Auflage, 2012
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