“Megadoses of Vitamin C for everybody?”
 ©2001 PFPC

Commentary by Wendy Small, July 2001

   Several articles have circulated  within the last several days critizing the way the media reported a recent study regarding possible Vitamin C gentoxic effects. The report in question appeared in the journal Science and alleges that mega-dose vitamin C supplements beyond 200 milligrams a day may promote the development of cancer-causing substances (Lee et al, 2001). 

   Many alternative “experts”were quick to slam the media reports, and disseminated information aimed at proving otherwise, using a selected  list of evidence culled from Medline.

   While everyone knows that the media frequently distorts scientific findings, the information supplied by those authors and others is just as false and irresponsible, contributing even more to the confusion which already exists in the consumer faced with so many conflicting "expert" advice.

   While some authors state that the "biological action of virtually very prescription drug can be duplicated with nutritional supplements at far less cost and with fewer side effects", threy has no problem advocating daily supplementation with Vitamin C, which is advocated as part of a daily health regimen.

   Vitamin C has been shown to be  beneficial in many treatments, and certainly should be considered effective medicine. We have used it with great benefit in treating some symptoms of fluoride poisoning (thyroid hormone dysfunction). However, there are many other aspects to consider.

   Vitamin C has been shown to be much more than just a "vitamin" as it is a required co-factor for numerous enzymes. For example, recent evidence suggests that dopamine requires ascorbic acid as a co-factor in prolactin-release inhibition (Shin et al, 1997).

   Is Vitamin C good for everyone and every day? Will the same dose have the same effect on different people? Of course not! For example, people on thyroid supplements will have inhibited absorption of ascorbic acid, as T3 inhibits the uptake of ascorbic acid. It has long been known that ascorbic acid affects the regulation of the levels of the circulating thyroid and adrenal cortical hormones.

   There are many other additional factors to consider in matters related to nutrition. For example, Robinson et al (1985) measured the rate of selenite-Se absorbtion. The selenite was taken two hours before a meal or mixed with 1 g ascorbic acid; or with a continental type breakfast providing 4.5-5.6 micrograms Se and 0.6-0.8 mg Cu, with or without 200 ml orange juice (60 mg ascorbic acid). While the light meal appeared to have little effect on selenite-Se absorption, and orange juice appeared even to assist it, the availability of Se was reduced almost to zero when selenite and 1 g ascorbic acid were taken together well before the meal. Se is an essential component of the deiodinases, enzymes which convert the prohormone thyroid hormone T4 into the active hormone T3.

   Ascorbic acid also increases the body’s absorbtion of aluminum, a very important factor to consider in all fluoride-related issues (Domingo et al, 1991, 1993; Fulton et al, 1990; Partridge et al, 1987).

   Why would anyone advocate daily use of such medication, whether its needed or not?

   Since the 1970s numerous information has surfaced that Vitamin C might also have adverse health effects. In 1998 Auer et al reported a) haematuria (blood in urine), hyperoxaluria - a disease which results in the deposition of calcium oxalate in the genitourinary system and kidneys (nephrocalcinosis) and which often leads to progressive renal failure - as well  crystalluria (excretion of crystals in the urine, producing renal irritation).

   In immature pigeons, administration of vitamin C increased mitotis as well as epithelial thickeness in the follicles of the thyroid in both sexes (Maiti & Sengupta, 1979).

   In response to the above study from “Science”, one author claimed that, "If vitamin C supplements are going to damage DNA and promote cancer, it will occur in the digestive tract (colon and rectum) where the concentration of vitamin C is the greatest when taking supplements".

   This is an entirely false statement. Greatest concentrations will always be found in the liver. The organism limits the absorption of physiological oral uptake of Vitamin C. When the limit is exceeded, the liver is unprotected and becomes swamped (Degwitz 1985).

   The liver, of course, is the major organ for thyroid hormone synthesis.

   Anybody who advises the public on such matters is supposed to be in knowledge of all factors before offering advice. Anything else is unethical. Our health is regulated by many factors, working together in the most intricate ways. Regarding thyroid hormones which are involved in every cell of our body, they are regulated by numerous highly sensitive feedback mechanisms.

   It is simple wrong and irresponsible to advise supplementation with anything on a daily basis, considering that such measures have the potential to upset such feedback mechanisms.

   It is indeed unfortunate that this leads to more and more confusion. The best advice one can give to the people is: Please conduct your own investigations and re-claim responsibility for your own health.

   Use common sense, and don't trust any of the "experts" - be they from the orthodox or alternative medicine fields!

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Auer BL, Auer D, Rodgers AL - "Relative hyperoxaluria, crystalluria and haematuria after megadose ingestion of vitamin C" Eur J Clin Invest 28(9):695-700 (1998)

Campbell A - "Development of a papillary thyroid carcinoma in a patient while on high dosage ascorbic acid therapy" Chem Biol Interact 30(3):305-8 (1980)

Degkwitz E - "New aspects of the biochemistry of vitamin C" Z Ernahrungswiss 24(4):219-30 (1985)

Domingo JL, Gomez M, Llobet JM, Richart C - “Effect of ascorbic acid on gastrointestinal aluminium absorption” Lancet 338:1467 (1991)

Domingo JL, Gomez M, Sanchez DJ, Llobet JM, Corbella J - “Effect of various dietary constituents on gastrointestinal  absorption of aluminum from drinking water and diet” Res Commun Chem Pathol Pharmacol 79 377-380 (1993)

Domingo JL, Gomez M, Llobet JM, Corbella J- “Influence of some dietary constituents on aluminum absorption   and retention in rats” Kidney Int  39 (4)  598-601 (1991)

Fulton B, Jeffery EH - “Absorption and retention of aluminum from drinking water. 1. Effect of citric and ascorbic acids on aluminum tissue levels in rabbits” Fundam Appl Toxicol 14:788-796 (1990)

Lee SH, Oe T, Blair IA - “Vitamin c-induced decomposition of lipid hydroperoxides to endogenous genotoxins” Science 292(5524):2083-6 (2001)

Maiti BR, Sengupta S - "Effect of vitamin C on the mitotic activity and follicular growth of the thyroid gland of juvenile pigeon" Arch Histol Jpn 42(4):423-6 (1979)

Nath N, Nath M, Muddeshwar MG - "Ascorbic acid in thyroidectomized rats. II) Ascorbic acid status of the storage tissues and hepatic biosynthesis of glucuronic acid" Acta Vitaminol Enzymol 6(2):91-5 (1984)

Partridge NA, Regnier FE, White JL, Hem SL - “Influence of dietary constituents on intestinal absorption of aluminum” Kidney Int 35:1413-1417 (1989)

Robinson MF, Thomson CD, Huemmer PK - "Effect of a megadose of ascorbic acid, a meal and orange juice on the absorption of selenium as sodium selenite" N Z Med J 98(784):627-9 (1985)

Shin SH, Si F, Chang A, Ross GM - "Dopamine requires ascorbic acid to be the prolactin release-inhibiting factor" Am J Physiol 273(3 Pt 1):E593-8 (1997)

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SEE ALSO:

Arthur JR - "The glutathione peroxidases" Cell Mol Life Sci
57(13-14):1825-35  (2000)

Chaudiere J, Ferrari-Iliou R - "Intracellular antioxidants: from chemical to biochemical mechanisms" Food Chem Toxicol 37(9-10):949-62 (1999)

Halliwell B - “Vitamin C and genomic stability” Mutat Res  475(1-2):29-35 (2001)

Maddaiah VT - “Glutathione correlates with lipid peroxidation in liver mitochondria of triiodothyronine-injected hypophysectomized rats” FASEB J 4(5):1513-8 (1990)

Proteggente AR, Rehman A, Halliwell B, Rice-Evans CA - “Potential problems of ascorbate and iron supplementation:
pro-oxidant effect in vivo?” Biochem Biophys Res Commun 277(3):535-40 (2000)

Seymen O, Seven A, Candan G, Yigit G, Hatemi S, Hatemi H- “The effect of iron supplementation on GSH levels, GSH-Px, and SOD activities of erythrocytes in L-thyroxine administration” Acta Med Okayama 51(3):129-33 (1997)

Williams MT, Carrington H, Herrera A - “Stimulation of mouse liver glutathione S-transferase activity in propylthiouracil-treated mice in vivo by tri-iodothyronine” Biochem J  233(2):595-8 (1986)