A recent study showed that breast cancer patients who took certain supplements while undergoing chemotherapy treatment may have risks of recurrence and death.
The study was published in the Journal of Clinical Oncology. Researchers found that supplements designed to increase levels of iron, antioxidants, vitamin B12 and Omega 2, tended to alter the success of chemotherapy.
The Chair of Cancer Prevention and Control, Christine Ambrosone, said, “From this study and others in the literature, it seems that it may not be wise to take supplements during chemotherapy, one-way chemotherapy works is by generating lots of oxidative stress. The thinking is that antioxidants may block oxidative stress and make chemotherapy less effective.”
Doctors in the past have recommended that their patients not consume antioxidants while they are receiving chemotherapy. But as Ambrosone said, “There was no strong empirical data for that recommendation.”
Ambrosone and other researchers studied the data from the Diet, Exercise, Lifestyle and Cancer Prognosis research to look more directly at the consequences of using supplements during chemotherapy.
The study focused on 1,134 patients who were studied for around 6 years. The group of patients used a low amount of supplements, with 20% consuming supplements before starting treatment and 13% consuming them during treatment.
After taking into account other causes that could be related to an increase in death or recurrence, Ambrosone and his colleagues found that patients who took supplements such as vitamins A and C, Coenzyme Q10, and carotenoids during chemotherapy were more likely to have breast cancer again. They were also 40% more likely to die than patients who did not use any type of supplement.
The results of the study were quite similar when looking at other antioxidants consumed before and during the treatment. As for the other supplements, the results were not as statistically significant.
Patients who usually consume B12 and Iron had a high risk of recurrence. Women who consumed B12 were 83% more prone to recurrence and had a 22% probability of death compared to those who did not consume the supplement. Women who consumed iron during treatment had a 79% chance of recurrence, while those who consumed Omega-3 had a 67% chance of recurrence.
Other studies have also suggested that iron “can play a role in both cancer initiation as well as promotion,” Ambrosone said.