Vitamin C half life

[Guest guest]

_http://www.cbn.com/cbnnews/news/040826a.aspx_

(http://www.cbn.com/cbnnews/news/040826a.aspx)

This site says the half life of vitamin C is 30 mins.

_http://www.newmediaexplorer.org/chris/2004/07/09/the_vitamin_c_fanatics_were_

right_all_along.htm_

(http://www.newmediaexplorer.org/chris/2004/07/09/the_vitamin_c_fanatics_were_ri\

ght_all_along.htm)

This site also says 30 mins.

_http://www.nutritionj.com/content/2/1/7_

(http://www.nutritionj.com/content/2/1/7)

This site explains that the body will not store a large amount of vitamin C.

Making the 10-20 day half life next to nothing in the body. In order to

maintain a large amount of vitamin C you have to continue with supplements.

Ascorbic acid being a water soluble compound is easily absorbed but it is

not stored in the body. The average adult has a body pool of 1.2–2.0 g of

ascorbic acid that may be maintained with 75 mg/d of ascorbic acid. About 140

mg/d

of ascorbic acid will saturate the total body pool of vitamin C [_7_

(http://www.nutritionj.com/content/2/1/7#B7) ]. The average half life of

ascorbic

acid in adult human is about 10–20 days, with a turn over of 1 mg/kg body and

a

body pool of 22 mg/kg at plasma ascorbate concentration of 50 μmol/ L [_8_

(http://www.nutritionj.com/content/2/1/7#B8) ,_9_

(http://www.nutritionj.com/content/2/1/7#B9) ]. Hence ascorbic acid has to

regularly supplemented through

diet or tablets to maintain ascorbic acid pool in the body.

_http://www.exrx.net/Nutrition/Antioxidants/VitaminC.html_

(http://www.exrx.net/Nutrition/Antioxidants/VitaminC.html)

This site explains that the body will excrete anything over 1500 mg. Again

making the half life period of AA next to nothing as far as a therapeutic dose

goes..

Excretion

The average half-life of AA is believed to be between 16 and 20 days (17).

Its half-life is inversely related to intake. The water-soluble properties of

vitamin C lead to urinary excretion of the vitamin. Metabolites of vitamin C

including dehydroascorbate (DHAA), oxalic acid, 2-O-methyl ascorbate, and

2-ketoascorbitol are also excreted from the body via the urinary system

(13,17).

The kidneys play a major role in vitamin C excretion and retention. DHAA and

AA can be reabsorbed by the kidney tubules as long as body pool levels are

equal to or less than 1500 mg. Levels within the body that are 1500 mg or less

will result in no urinary excretion of vitamin C (13). As levels increase

above 1500 mg the reabsorption efficiency of the kidneys decreases. Thus, body

pool levels from 1500 to 3000 mg relate to tissue saturation of the vitamin

(13). Plasma ascorbate levels between 0.8 and 1.4 mg/dl are considered the

renal threshold. Above these levels, vitamin C will be excreted rather than

reabsorbed by the kidneys (13).

_http://www.vitamincfoundation.org/topten/_

(http://www.vitamincfoundation.org/topten/)

This site says half life is 30 mins.

_http://www.knowledgeofhealth.com/report.asp?story=Flaw%20In%20Analyzing%20Eff

ect%20Of%20Vitamin%20C%20On%20Cardiovascular%20Disease%20Revealed & catagory=Hea

rt%20Disease,%20Vitamin%20C_

(http://www.knowledgeofhealth.com/report.asp?story=Flaw%20In%20Analyzing%20Effec\

t%20Of%20Vitamin%20C%20On%20Cardiovascular%20Di

sease%20Revealed & catagory=Heart%20Disease,%20Vitamin%20C)

Again 30 minutes

_http://www.hullcontactlensclinic.co.uk/cardior.htm_

(http://www.hullcontactlensclinic.co.uk/cardior.htm)

Again 30 minutes for high doses 8 -40 days low doses

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