Antioxidants and Vitamins May Not Help in Breast Cancer
Breast cancer patients who take antioxidants may have an increased or decreased risk of death or recurrent cancer, depending on which vitamin they use, a new study suggests.
Researchers found that among nearly 2,300 women with early-stage breast cancer, those who regularly used either vitamins C or E had a lower risk of cancer recurrence over five years than those who didn't use the vitamins.
On the other hand, women who regularly took a mix of carotenoids had a higher risk of dying from breast cancer, or any other cause, than women who did not take them. Carotenoids include nutrients like vitamin A, beta-carotene and lutein.
The findings, reported in the journal Cancer, do not prove that any of the antioxidants are the reason for the effects seen.
But they do add to concerns about the risks of high doses of carotenoids, according to lead researcher Heather Greenlee, an assistant professor of epidemiology at Columbia University in New York.
There is also concern about patients taking high doses of any antioxidant while on chemotherapy or radiation.
What are antioxidants?
Antioxidants protect body cells from so-called oxidative damage. Cancer drugs and radiation work in part by creating oxidative damage. So in theory, high-dose antioxidants could diminish the cancer treatment’s effectiveness.
Studies indicate that women with breast cancer commonly use antioxidant supplements of some kind.
According to Greenlee, much of the benefit associated with vitamins C and E could potentially be explained by a "healthy user bias" -- that is, women who use dietary supplements tend to have healthier habits in general.
And that, she and her colleagues write, makes the increased risk of death linked to carotenoid use "even more striking."
The reasons for the different breast cancer outcomes linked to different antioxidants are not known, and the findings need to be confirmed in further studies, Greenlee said.
The most important point this study raises, she added, is that "antioxidant dietary supplements should not be assumed to all act in a similar fashion, as is a common perception in the general public."
"They are made up of different molecules," Greenlee said, "and likely have different effects."
On the other hand, the researchers found no evidence that breast cancer recurrence or deaths were linked to antioxidants taken within multivitamins which generally have more moderate doses of individual nutrients.
Message For You: Antioxidants and vitamins in diet are a preventive measure against any cancer. But, patients who already have the disease should check with oncologist experts before popping any pills or enriching diet with antioxidants or vitamins. Tina Khanna diet expert with DesiDieter preaches “as this paper indicates antioxidants and vitamin may possibly interfere with the cancer treatment. So, check with a cancer specialist before taking any nutritional supplement.”
Source: http://www.nlm.nih.gov/medlineplus/news/fullstory_117342.html
