A diagnosis of breast cancer can bring new worries about survival. It’s possible that a common vitamin may help improve the outlook.
A few studies have looked at whether vitamin C decreased risk of death after breast cancer. Recently, a research team analyzed several of those published studies to summarize the evidence.
The results suggested that vitamin C supplements were linked to a reduced risk of death in women after a breast cancer diagnosis. Higher vitamin C in the diet, found in citrus fruits, was associated with a lower risk of death and a lower risk of breast cancer-related death.
The lead author of this research publication was Holly R. Harris, ScD, MPH, from the Division of Nutritional Epidemiology at the Institute for Environmental Medicine at the Karolinska Institutet.
Dr. Harris and her team analyzed 10 studies in which vitamin C was studied in women after a breast cancer diagnosis. The studies included 17,696 cases of breast cancer.
Six studies looked at the association between vitamin C supplements and survival in general and breast cancer-related death specifically. Seven of the 10 studies looked at the association between dietary vitamin C and the same outcomes.
Taking vitamin C supplements after a breast cancer diagnosis was associated with a 19 percent decreased risk of death compared to not taking vitamin C. Vitamin C supplements decreased the risk of breast cancer-specific death by 15 percent compared to not taking vitamin C.
Compared to women with low amounts of vitamin C in their diet, patients who ate high amounts of vitamin C had a 23 percent decreased risk of breast cancer-specific death.
When breast cancer patients increased the amount of vitamin C in their diet by 100 mg a day, their risk of death went down 27 percent compared to before they increased their intake. The risk of breast cancer-specific death went down by 22 percent in the women who increased vitamin C in their diet by 100 mg per day compared to no increase in vitamin C consumption.
The authors of this study noted that their analysis had some limitations. Since they were analyzing the research of others, Dr. Harris’s team was not able to take into account other factors, such as body weight that may have influenced the results. They also remarked that survivors who took vitamin C supplements may have been more health conscious in general than other breast cancer survivors.
“In conclusion, results from this meta-analysis suggest that post-diagnosis vitamin C supplement intake did not have a negative impact on breast cancer survival and may be associated with a reduced risk of mortality [death]. Dietary vitamin C intake was also associated with a reduced risk of total mortality and breast cancer-specific mortality,” the authors wrote.
The research publication appeared in the May issue of the European Journal of Cancer.
Support for the study was provided by the Swedish Cancer Foundation.
The authors declared no conflicts of interest.