Consuming certain supplements during chemotherapy for breast cancer increases death risk, says study

According to the researchers, dietary supplements increase the level of antioxidants, omega-3 fatty, vitamin B12 and iron, which seem to reduce the potency of chemotherapy

Women undergoing chemotherapy after being diagnosed with breast cancer have been advised by doctors to not consume antioxidant supplements during the treatment for years. Providing the data to legitimize the advice, a new study suggests that consuming supplements during chemotherapy can increase the risk of relapse and death.

According to the researchers, dietary supplements increase the level of antioxidants, omega-3 fatty, vitamin B12 and iron, which seem to reduce the potency of 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," said Christine Ambrosone, chair of cancer prevention and control, and senior vice president for population sciences at the Roswell Park Comprehensive Cancer Center in Buffalo, New York, as quoted by Reuters.

Studying the use of supplements before and during chemotherapy

In order to understand the possible connection between the use of supplements and its effect on chemotherapy, the researchers analyzed data from the Diet, Exercise, Lifestyle and Cancer Prognosis study. The research derived from a trail formulated to ascertain the ideal schedule and dosage of drugs, meant for chemotherapy.

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The study centred on 1,134 patients as they were asked about the consumption of supplements at the beginning and during the course of the treatment. Also recorded were habits such as exercise, lifestyle, and diet. It was found that this collection of patients used to supplement at a rate much lower than normal. 20 percent of them took supplements before the commencement of their treatment, while 13 percent did during the course of their treatment.

All supplements presented risks

After taking into account additional factors that may raise the risk of death or recurrence, it was found that patients who took antioxidants at the beginning and during chemotherapy, were 40 percent more likely to die during review and 41 percent more likely of having a recurrence of breast cancer. This was in comparison to the patients who did not take any supplements such as vitamins A, C, and E, Carotenoids, and Coenzyme Q10.

The results held good for most of the individual antioxidants, especially vitamin A. Women who consumed iron supplements and B12 were at higher risk of recurrence. Among women who consumed B12, 83% were likely to see their cancer return while 22% were more likely to die during follow-up. 67 percent higher risk was noted among women taking omega-3 supplements prior and during chemotherapy were likely to experience recurrence, while 79% increased risk was recorded among those consuming iron supplements.

Substantiation of the long-held belief

"From this study and others in the literature, it seems that it may not be wise to take supplements during chemotherapy," said Christine Ambrosone. Expressing her appreciation for the study and its impact, Amy Tiersten, a professor of medicine, oncology, and haematology at the Icahn School of Medicine at Mount Sinai, told Reuters, "For years we have been cautioning patients about the use of vitamins, in particular, anti-oxidants, during chemotherapy for breast cancer."

Habits to avoid during cancer treatment

By avoiding certain habits and employing caution during treatment, one can reduce the chances of cancer's recurrence. Some of them are:

This article was first published on December 24, 2019