Vitamin C and cancer - August 05, 2008
It’s time for another ride on ‘vitamin C cures cancer’ rollercoaster. Some readers may recall that chemist Linus Pauling took a long ride a while ago and was never quite the same after. Exercise caution people.
In a paper published this week in PNAS Qi Chen, of the US National Institutes of Health, and colleagues show that injected vitamin C (ascorbate) can halve the growth rate of tumours in mice. The team tested vitamin C injections in mice with rapidly spreading ovarian, pancreatic, and brain tumours. Injections reduced tumour growth by 41% and appeared to control spreading to other organs.
By injecting vitamin C you can produce far higher levels of ascorbate than you can achieve with oral tablets. High concentrations of ascorbate generate hydrogen peroxide, which is known to slow tumours in mice, they write.
“Similar pharmacologic concentrations [of vitamin C] were readily achieved in humans given ascorbate intravenously,” say the researchers. “These data suggest that ascorbate as a prodrug may have benefits in cancers with poor prognosis and limited therapeutic options.”
Alison Ross, from charity Cancer Research UK, says (BBC), “This is encouraging work but it’s at a very early stage because it involves cells grown in the lab and mice. There is currently no evidence from clinical trials in humans that injecting or consuming vitamin C is an effective way to treat cancer.
“Some research even suggests that high doses of antioxidants can make cancer treatment less effective, reducing the benefits of radiotherapy and chemotherapy.”
New Scientist notes:
Definitive answers on the effectiveness of intravenous vitamin C will only come from subsequent larger trials. But given recent experiences with a drug called DCA, which some patients began taking without medical supervision after reading about promising results on cancer cells, there are concerns that patients may take matters into their own hands by injecting themselves with vitamin C or taking large doses of vitamin C pills.
The use of high dose vitamin C as a complementary or alternative cancer treatment has a long history dating back to the 1970s. ... Patients have taken the vitamin both by mouth and intravenously. But despite some positive outcomes, reliable evidence that the therapy works has been lacking. For this reason claims that vitamin C can treat cancer have been dismissed by conventional cancer experts.
And, as if you needed to be told, unconventional cancer experts are probably best avoided...
Image: Mark Levine
Comments
While caution is appropriate, I think the above essays is a little TOO cautious. Injectable ascorbate has shown to be promising by more than one researcher. Anyway, for an excellent discussion of the history of this controversy see the book LINUS PAULING: A MAN AND HIS SCIENCE, by anthony serafini
Posted by: Hobart Cidrule | August 11, 2008 01:30 PM
Alison Ross claims that there is no evidence from clinical trials that vitamin C has value in cancer treatment, but she is wrong. Pauling and Cameron published two clinical reports involving more than one thousand patients in PNAS in the late 1970s. Cameron and Campbell published a clinical trial of 50 consecutive cancer patients given high-dose vitamin C in Chem.-Biol. Interactions in 1974. Recent clinical reports on favorable responses to high-dose vitamin C have been published in CMAJ and JACN. There's plenty of evidence suggesting benefit for some patients if you care to look.
Posted by: Stephen Lawson | September 6, 2008 12:59 AM
I found this info very useful, and will tell my family about this because they are always looking for better solutions. Thank you!
Posted by: Daryl Saari | October 7, 2008 02:43 AM
If Vitamin c in high doses can help reduce tumours in mice then I would have thought it would do similar in humans. What dose is being used?
Posted by: mike | December 5, 2009 07:16 PM