Vitamin C, also known as ascorbic acid, is a water-soluble vitamin that is essential to maintain human body health. It is essential because human body is unable to synthesise vitamin C due to the lack of enzyme, L-gluconolactone oxidase. Fortunately, vitamin C can be obtained from fruits and vegetables such as citrus fruit, pepper, broccoli, tomatoes, and many more.
Vitamin C plays an important role in improving the immune system, biosynthesis of collagen, and preventing chronic disease caused by oxidative damage. Severe vitamin C deficiency can cause scurvy with symptoms such as fatigue, muscular weakness, swollen gums, and poor wound healing.
Vitamin C is important in enhancing the differentiation and proliferation of B- and T-cells which result in improving the generation of antibodies³. Vitamin C also acts as a stimulant of leukocyte functions, especially of neutrophil and monocyte movement. Research indicates that supplementation of vitamin C enhances natural killing cell activity up to ten-fold in 78% of patients who were exposed to toxic chemicals before⁷.
Vitamin C provides direct antioxidant protection by scavenging numerous reactive oxygen species and reducing free radical generation in plasma. This helps to prevent chronic diseases that are caused by oxidative damage such as cardiovascular diseases, atherosclerosis, and aging. Vitamin C also provides indirect antioxidant protection by regenerating vitamin E and maintaining glutathione in reduced form² Research indicates that daily intake ≥700mg of vitamin C can reduce the risk of coronary heart disease incidence by 25%⁸.
Vitamin C enhances the absorption of non-heme iron in gastric fluid and helps to prevent iron deficiency anemia. Research show iron absorption increase double after adding ascorbic acid into cow milk containing sulphate ferrous with molar ratio (ascorbic acid-iron), 2:1¹.
Vitamin C stimulates collagen mRNA production by fibroblasts and acts as a cofactor for the proline and lysine hydroxylases enzymes to enhance stabilisation of the tertiary structure of collagen. Vitamin C also helps to inhibit melanogenesis by reducing the ortho-quinones generation as well as assisting in antioxidant protection of the skin against UV-induced photodamage⁵.
Ascorbate act as a cofactor for the biosynthesis of noradrenaline and serotonin. It is also important as a modulator in glutaminergic, cholinergic, and GABAergic transmission as well as provides a neuroprotective function in neural maturation².
In general, vitamin C is well tolerated and rare to cause serious side effects as an excessive amount of vitamin C will be excreted from the body through urine. The most common adverse effect are abdominal cramps, esophagitis, heartburn, headache, diarrhea, nausea and vomiting.
Dietary Reference Allowance (DRA) for Vitamin C6
| Age | Male | Female | Pregnancy | Lactation |
|---|---|---|---|---|
| 0-6 months | 40mg | 40mg | ||
| 7-12 months | 50mg | 50mg | ||
| 1-3 years | 15mg | 15mg | ||
| 4-8 years | 25mg | 25mg | ||
| 9-13 years | 45mg | 45mg | ||
| 14-18 years | 75mg | 65mg | 80mg | 115 mg |
| 19+ years | 90mg | 75mg | 85mg | 120mg |
*Daily vitamin C intake of smokers needs 35mg more than nonsmokers.
– Aluminium: containing antacids:
Increases the aluminium absorption.
– Warfarin:
Reduces the activity of anticoagulants.
– Estrogen:
Increases the serum concentration of oestrogen derivatives.
– Antihypertensive drugs:
Potential side effects may occur when consumed together with grape seed extract.
In general, vitamin C is well tolerated and rare to cause serious side effects as an excessive amount of vitamin C will be excreted from the body through urine. The most common adverse effect are abdominal cramps, esophagitis, heartburn, headache, diarrhea, nausea and vomiting.
Dietary Reference Allowance (DRA) for Vitamin C6
| Age | Male | Female | Pregnancy | Lactation |
|---|---|---|---|---|
| 0-6 months | 40mg | 40mg | ||
| 7-12 months | 50mg | 50mg | ||
| 1-3 years | 15mg | 15mg | ||
| 4-8 years | 25mg | 25mg | ||
| 9-13 years | 45mg | 45mg | ||
| 14-18 years | 75mg | 65mg | 80mg | 115 mg |
| 19+ years | 90mg | 75mg | 85mg | 120mg |
*Daily vitamin C intake of smokers needs 35mg more than nonsmokers.
– Aluminium: containing antacids:
Increases the aluminium absorption.
– Warfarin:
Reduces the activity of anticoagulants.
– Estrogen:
Increases the serum concentration of oestrogen derivatives.
– Antihypertensive drugs:
Potential side effects may occur when consumed together with grape seed extract.
The material is prepared for informational purposes only and should not be construed as a piece of personal medical advice. Owing to each person’s varying health needs, a physician should be consulted before acting on any information provided in this material. Although every effort is made to ensure that this material is accurate, it is compiled for internal use only and should not be considered definitive. Neither VitaHealth nor its employees, or information providers shall be responsible or liable for any errors, inaccuracies, or other defects in the information contained in this publication.
L-theanine is a unique water-soluble non-protein amino acid with structure resembles that of L-glutamate acid. It is predominantly present naturally in tea, Camellia sinensis or
