KEY POINTS:
Vitamin C has often been a homespun remedy for all manner of ills - but groundbreaking New Zealand research shows it could even help beat cancer by making treatments such as chemotherapy more effective.
A study led by Dr Margret Vissers from Otago University's Free Radical Research Group has demonstrated the vitamin's importance in maintaining cell health and the role it plays in limiting diseases such as cancer.
"A lot of scientists have been a bit sceptical of people taking vitamin C when they have a cold, or when they feel like they've got the flu, or when they're undergoing cancer treatment - and lots of people do this. There really hasn't been a rationale to explain why you might want to do that. And now there might be," she said.
Dr Vissers, along with colleagues from the Christchurch School of Medicine, conducted a series of experiments showing the key role vitamin C played in healthy cells and in controlling cell activity throughout the body.
"The mechanism that I have found says that if your cells contain a good amount of vitamin C, they will undergo normal life processes like growing and dying. If they don't, then those processes are disrupted, and those are the things that are disrupted in cancer cells."
With the normal cell death process interrupted, cancer cells become quite resistant to treatment.
"If we could make those cancer cells respond better to the chemotherapy, it would mean that you'd get a better result, and you would possibly need less drugs."
Dr Vissers said cancer cells appeared to behave like normal cells that were deficient in vitamin C.
She is now testing tumour tissue to see if it is low in the vitamin, and investigating whether boosting levels will make a difference to standard cancer treatments outcomes.
The test results may hold a key to making current cancer treatments more effective.
Dr Vissers said it could make the difference between "getting a result where you actually get rid of all of the cancer, rather than getting rid of most of it, and having this residual bit that will grow back".
She warns against using her study to justify taking high doses of vitamin C supplements. Plenty of regular fruit and vegetable consumption is enough.
The results of the Health Research Council-funded study appear in two peer-reviewed journals, The Journal of Leukocyte Biology and Free Radical Biology and Medicine.
How it works and why you need oranges
* Key enzymes in the cell, dubbed hydroxylases, need vitamin C to be activated. Having low levels of the vitamin means these enzymes are less likely to work.
* Hydroxylases control a transcription factor within the cell called HIF-1. It turns on specific genes, changing the way the cells respond to stress and controlling cell death and growth.
* When vitamin C is low or absent, the HIF-1 transcription factor turns on, enabling cancer cells in tumours to make more blood vessels, grow and resist chemotherapy.
* The finding is not a justification for extensive supplementation in people enjoying normal health. Regular fruit and vegetable consumption is enough.
