The advance of cancers could be held back by an injection of a high dose of vitamin C, claim US scientists, adding that the vitamin may be reacting with cancer cell chemicals to make acid.
The journal Proceedings of the National Academy of Sciences reported that in mice, the jab halved the size of brains, ovarian and pancreatic tumours.
Yet, other studies suggested that large doses of vitamin C could actually interfere with cancer treatment, said Cancer Research UK.
Also called ascorbate, the vitamin could kill cancer cells in the laboratory, suggested earlier research by the team at the National Institutes of Health in Maryland.
Now, after successful tests in mice, they are suggesting that the treatment be considered for human use, at similar levels.
Because the digestive system does not absorb more than a fixed amount taken orally, the dose they employed, up to four grams per kilo of bodyweight, was far greater than any that could be achieved using diet or vitamin pills.
After being bred in order to have malfunctioning immune systems, the mice were injected with human cancer cells, and as a result, grew quickly into large tumours. Then, the vitamin was injected into their abdominal cavity.
While in untreated mice the disease spread rapidly to involve other body parts, in the vitamin C-treated animals, tumour growth and weight fell by between 41% and 53%.
“These pre-clinical data provide the first firm basis for advancing pharmacologic ascorbate in cancer treatment in humans”, wrote researchers.
A tumour cell is chemically different to a healthy cell, which is why the treatment works. The vitamin C reacts with this chemical make-up, producing enough hydrogen peroxide to kill the cell, while leaving healthy cells unscathed.
Nevertheless, in order to see if vitamin C could be a viable treatment, much more work would have to be done, said Dr Alison Ross, from Cancer Research UK.
“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.”