An animal study appearing in the American Journal of Clinical Nutrition (1991;54:1256S-60S) demonstrated that vitamin C inhibits kidney tumors induced by estrogen. The Journal of the National Cancer Institute (1990:82:561- 569) stated that there was an inverse association with breast cancer risk and vitamin C intake. In many circles there has been interest in vitamin C as an adjunctive cancer treatment. In a symposium held by the National Cancer Institute in December, 1990, 40 papers were presented that showed the value of vitamin C for cancer patients. A number of other animal studies showed the inhibitory effect of vitamin C on tumor growth. IV vitamin C has actually shrunk tumors in patients with adenocarcinoma (IV vitamin C is used extensively in Germany for cancer patients).
Vitamin C protects the cell as an antioxidant. In the journal Biological Chemistry (May 10, 2002;277(19):16895-16899) demonstrated that vitamin C prevented mutations in cell exposed to oxidative stressors. Another study appearing in FEBS Letters (1998;363:363-367) showed that vitamin C plays a role in repairing DNA. Vitamin C also enhances natural killer cell activity (cells important in immunity and fighting cancer), according to research in Nutrition Research (1993;13:753-764).
In an animal study appearing in Carcinogenesis (2009;July:30(7)), scientists found that vitamin C may protect against estrogen induced breast tumors. The study was performed on rats bred to easily develop breast tumors. In animals given estradiol, 82% developed breast tumors. Rat who were given a combination of vitamin C and estradiol had 29% fewer tumors over the 240 day course of the study.
Granted, a lot of these studies are small, involve animals or took place in a Petri dish, but the results are hopeful. Also, vitamin C is very inexpensive. Considering that vitamin C plays a role in cancer therapy in other countries, perhaps we should look into it as well.