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