Q. I have an aggressive form of breast cancer being treated by some powerful chemotherapy drugs. A friend is warning me that some vitamins should be avoided during chemo. Which vitamins are these?
A. Your friend is probably responding to widely publicized research from 1999 that led some people to believe that antioxidant nutrients would hinder the ability of chemotherapy drugs to kill cancer cells. Some of this research was done in test tubes rather than in live animals, and the results from these experiments have not been duplicated in live-animal research. Other research was done using a strain of mutant mice, and results from this research may be impossible to apply to humans.
An increasing number of cancer patients combine complementary treatment with conventional therapy. You should inform your oncologist if you are using nutritional or herbal remedies, because there are occasional mismatches. Fortunately, it appears that antioxidant nutrients are not only safe to use but may actually enhance the effectiveness of chemotherapy. Your oncologist should be able to tell you which chemotherapy agents are the exceptions.
The concern centers on the ability of antioxidants to neutralize “reactive oxygen species” or ROS, which we also commonly term “free radicals.” ROS are high-energy molecules that can be damaging to cells when not kept in control by antioxidants. These ROS are also used by all of our cells to generate energy so we can never do without them entirely. Since many anti-cancer agents generate ROS as part of their therapeutic effect, the fear arose that antioxidant nutrients would interfere with their ability to kill cancer cells. A careful review of the research reveals that in clinical practice, antioxidants almost never interfere with the effectiveness of chemotherapy.
The best news is that almost invariably the clinical studies show that antioxidant supplements enhance the effectiveness of conventional cancer treatment. Because anti-cancer drugs are most effective against rapidly dividing cells, during chemotherapy (but only during chemotherapy) we want the cancer cells to divide rapidly. When antioxidants are depleted, cancer cells tend to become temporarily dormant, and that interferes with the effectiveness of chemotherapy.
Furthermore, antioxidants can reduce the incidence of side effects from chemotherapy without sacrificing results. Heart damage from adriamycin, a common anticancer drug, is obliterated through the use of supplements of vitamin E or coenzyme Q-10. Kidney damage, hearing loss, hair loss, weight loss, and many other traumatic effects of chemotherapy can be minimized when nutritional supplements are employed along with the drugs.
Antioxidants are best used in combination rather than alone. You should have no trouble finding a multiple antioxidant formula that would supply reasonable amounts of vitamin E, vitamin C, beta-carotene, coenzyme Q-10, and selenium. A formula containing these, plus any or all of the following less common antioxidants would be even better: n-acetyl cysteine, glutathione, citrus bioflavonoids, and proanthocyanidins.
Antioxidant nutrients are part of the solution to cancer and rarely need to be avoided.
This article appears in December 7 • 2001.