High doses of vitamin C could be a safe and potentially effective form of cancer treatment, scientists claim.
By injecting patients with it, they are able to get up to 1,000 times the amount than they would through eating.
This amount of the nutrient, found in oranges, kale and peppers, actively hunts tumours when it enters the blood stream, research suggests.
It worked by weakening the cancerous cells, leaving them vulnerable to the effects of radiation and chemotherapy.
Despite evidence showing the opposite, the high doses produced only mild side effects of frequent bathroom trips and a dry mouth.
Vitamin C has been studied internationally as a potential treatment for cancer patients for more than four decades.
Despite being known to help boost the immune system, proven results for its effects on cancer have been relatively scarce.
Eleven brain cancer patients were given three infusions of vitamin C a week for two months for the study, which was published in the journal Cancer Cell.
This was followed by a further two per week for seven months while receiving standard radiotherapy and chemotherapy.
With standard treatment, patients with this form of the disease can expect to live for around 14 to 16 months.
However, the University of Iowa researchers found that high doses of vitamin C could extend their lifespan by up to six months.
Tests showed that iron in their tumours reacted with the vitamin to form highly reactive and destructive ‘free radical’ hydrogen peroxide molecules.
The free radicals were thought to cause selective DNA damage in cancerous, but not healthy, cells.
This in turn was expected to lead to enhanced cancer cell death as well as sensitisation to radiation and chemotherapy drugs.