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# Prediagnosis vitamin C helps survival in breast cancer patients
- URL: https://www.foodconsumer.org/vitamin_c_breast_cancer_0609130821/
- Published: 2013-06-09T09:20:00.000Z
- Updated: 2026-09-22T16:18:35.000Z
- Description: Among 3,405 Swedish women with invasive breast cancer, those in the highest quartile of vitamin C intake before diagnosis were 25 percent less likely to die of breast cancer and 16 percent less likely to die of any cause. Vitamin C use after diagnosis showed no association.
- Author: Food Consumer
- Tags: Vitamins, Nutrition, #vivvo-import

Sunday June 9, 2013 (foodconsumer.org) -- Taking prediagnosis vitamin C or ascorbic acid, a common antioxidant dietary supplement, may reduce the risk of death from all causes and breast cancer, according to a new study in British Journal of Cancer.

H. R. Harris and colleagues from Karolinska Institutet in Stockholm, Sweden conducted the study and found taking high doses of vitamin C prediagnosis was associated with 16% reduction in all-cause mortality and 25% reduction in mortality from breast cancer.

High doses of vitamin C may potentially act as a pro-oxidant, which may cause the formation of reactive oxygen species and kill cancer cells. High doses of vitamin C administered via IV injection have been used by alternative practitioners to treat a variety of cancer. But drug companies and the medical circle do not believe that vitamin C has any efficacy in treating cancer.

In the study, using a food frequency questionnaire, the researchers surveyed the use of vitamin C pre-diganosis and postdiagnosis in 3,405 women diagnosed with invasive breast cancer who were enrolled in the Swedish Mammography Cohort. Between 1987 and 2010, 1,055 deaths from all causes with 416 deaths from breast cancer were documented. 

Adjustment for other factors, women in the highest quartile of pre-diagnosis vitamin C intake were found 25% and 16% less likely to die from breast cancer and all causes, respectively, compared with those in the lowest quartile. 

However, no association was found between postdiagnosis vitamin C supplement use (about 1000 mg per day) and breast cancer mortality in 717 women who used vitamin C dietary supplement postdiagnosis. (it is possible that the finding was not significant enough because not as many patients could be used for the analysis to yield a significant result).

The researchers concluded "dietary vitamin C intake before breast cancer diagnosis may be associated with breast cancer survival. In addition, post-diagnosis vitamin C supplementation at the level observed in our population was not associated with survival."

It should be noted that about 1000 grams of vitamin C per day may not be sufficient to have an protective effect against breast cancer. Dr. Linus Pauling, Nobel Prize laureate, had advocated for taking high doses of vitamin C. He suggested a few grams of vitamin C per day is needed even for older healthy individuals to maintain their health. (reporting by Jimmy Downs)