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# Prediagnostic vitamin C use helps breast cancer survival
- URL: https://www.foodconsumer.org/prediagnostic_vitamin_c_use_helps_breast_cancer_survival_0715130/
- Published: 2013-07-15T18:58:00.000Z
- Updated: 2026-09-22T16:23:55.000Z
- Description: Among 3,406 women in the Swedish Mammography Cohort diagnosed with invasive breast cancer, those in the highest quartile of pre-diagnosis vitamin C intake had a 25% lower risk of breast cancer death. Supplementing with 1,000 mg a day after diagnosis showed no survival benefit.
- Author: Food Consumer
- Tags: Vitamins, Nutrition, #vivvo-import

Monday July 15, 2013 (foodconsumer.org) -- A brand new study published in British Journal of Cancer suggests that breast cancer patients may have a better survival if they take vitamin C supplements prediagnostically.

The study led by H.R. Harris and colleagues also shows that postdiagnostic supplementation of vitamin C was not associated with a better survival in breast cancer patients.

Vitamin C as an antioxidant is expected to influence cancer progression, but observational studies on vitamin C intake of breast cancer survival were inconsistent and the safety of vitamin C supplementation postdiagnosis remains unknown, according to the authors.

The current study was based on dietary data from 3406 women diagnosed with invasive breast cancer in the Swedish Mammography Cohort. Participants were surveyed using a food frequency questionnaire for their vitamin C intake. During a follow-up of 23 years, 1055 participants died with 416 deaths from breast cancer.

The researchers found breast cancer patients in the highest quartile of pre-diagnosis vitamin C intake were at 25 percent reduced risk of breast cancer death compared with those in the lowest quartile.

There was a borderline significant association between prediagnostic vitamin C intake and total mortality and the risk was reduced overall by 16%.

However, postdiagnostic vitmain C supplementation in a dose of 1000 mg per day was not found associated with a reduced risk of dying from breast cancer.

The researchers concluded "Our findings suggest that 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 the study merely found one gram of vitamin C per day does not affect the risk of dying from breast cancer. It does not prove that higher doses won't provide any benefits. 

Some studies suggest that in order to have a therapeutic effect, higher doses of vitamin C are needed. And if possible, vitamin C should be IV-administered to maintain a high serum level of vitamin C, which can kill cancer cells. (reporting by Jimmy Downs)