Cancer patients, be careful with those Vitamin C pills, say Hong Kong scientists – South China Morning Post (subscription)
Antioxidants, a substance long been seen as being beneficial to one’s health, have been found to facilitate the growth of liver cancer cells, a University of Hong Kong study revealed.
While antioxidants have been considered a healthy substance that combats free radicals, which damage cells, the research team found that they were also necessary for the growth of cancer cells.
“It might just be half true that antioxidants are beneficial to health, as cancer cells also need a lot of antioxidants,” said Dr Carmen Wong Chuk-Lui, assistant professor at the university’s department of pathology.
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In the study, liver cancer cells were found to produce more antioxidants through an enzyme named transketolase, which facilitated the growth of the tumour.
Other kinds of cancer, including colorectal and lung cancer, were also seen to have a similar growth pattern.
If the antioxidant-facilitating enzyme was suppressed, the tumour was found to be 30 to 40 per cent smaller.
While cancer patients might be taking antioxidant supplements such as vitamin C tablets for extra nutrients, the research team said they might need a change.
“People usually think that antioxidants are useful to fight against cancer. Here we raise a big question mark against it,” said Professor Irene Ng Oi-Lin, who led the study.
She said one supplement tablet might contain 500 to 2,000 milligrams of Vitamin C, far exceeding the 100 mg necessary for an adult every day.
“[Cancer patients] might not need to stop taking it, but they need to consider whether it is necessary to continue,” Ng said.
This, however, does not mean that cancer patient should stop eating fruits rich in antioxidants. Examples include oranges, lemons and papayas.
“Apart from vitamins, fruits also contain other kinds of nutrients that patients need. They should refrain from taking too many health supplements,” Wong said.
The research findings provided scientists with a new approach to treating liver cancer, which is difficult to cure completely. A highly deadly cancer which in 80 per cent of cases cannot be treated by operating, it is resistant to conventional chemotherapy and has one form of targeted therapy only.