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Certain Supplements Before & During Chemotherapy May Be Risky

Taking Certain Supplements Before and During Chemotherapy for Breast Cancer May Be Risky
January 9, 2020

A small study suggests that people who took antioxidant supplements before and during chemotherapy to treat breast cancer may have a higher risk of recurrence and death. Read more...


  • mountainmia
    mountainmia Member Posts: 857
    edited January 2020

    Thanks for the information. However, THIS was very confusing:


    • People taking omega-3 fatty acids both before chemotherapy and during chemotherapy were 67% less likely to have a recurrence.

    "Although this is an observational study and the number of users of supplements was fairly small, the results are compelling," said Christine Ambrosone, chair of the Department of Cancer Prevention and Control at the Roswell Park Comprehensive Cancer Center and lead author of the study. "Patients using any antioxidant before and during chemotherapy had an increased risk of the breast cancer returning and, to a lesser degree, had an increased risk of death. Vitamin B12, iron, and omega-3 fatty acid use was also associated with poorer outcomes." '

    The lead author says omega-3 use was associated with poorer outcomes. The summary bullet points say that omega-3 fatty acids use indicated a lower risk of recurrence. Which is it?

  • moderators
    moderators Posts: 7,665
    edited January 2020

    Thank you MountainMia for bringing this to our attention! This was an error on our part -- the story should have read:

    "People taking omega-3 fatty acids both before chemotherapy and during chemotherapy were 67% more likely to have a recurrence."

    We have made this correction now. Thank you so much again for notifying us of this oversight!

    --The Mods

  • HopeHeal
    HopeHeal Member Posts: 137
    edited March 2021

    The study is murky about the dosages of the supplements. If they say a multivitamin does not affect outcome then low dose supplements are probably safe. I take supplements in low doses only to replace what is missing from my diet, rather than one multivitamin because the multi has certain nutrients I want to avoid, such as iron and calcium that is not chelated which can cause GI symptoms. So I essentially separate out only the nutrients I need into individual pills.

    It stands to reason then that the participants taking supplements may have been high dosing, as most supplements are sold in high doses, but the study doesn't say. This is further supported by the researchers conclusion that diet is the best way to obtain nutrients as it more efficiently avoids overdosing.

  • Member Posts: 1,435
    edited March 2021

    HopeHeal, since you will be having chemo and presumably will be going onto anti-hormone therapy afterwards, you should ensure that your MO is aware of every supplement you take. I'm not suggesting that the MO will have a problem with anything, but they should know. In my case my MO was fine with everything I take, suggested some others (specifically because I'm on an AI, which can impact bones) and said "oh good" to a couple of them, which I appreciated.

  • olma61
    olma61 Member Posts: 1,016
    edited March 2021

    My MO said absolutely no anti-oxidants during chemo and I obeyed her. The rationale is, to oversimplify “what protects the good cells in your body will also protect the cancerous cells”. It makes sense to me.

  • Esther01
    Esther01 Member Posts: 229
    edited August 2021

    It depends on whether they are taken orally (antioxidant at small doses) or with high dose IV vitamin C. At high dose IV (50 grams), the vitamin C becomes pro-oxidant and many cancer patients around the world are benefiting from it throughout our treatments. The doctor just needs to screen us first for the G6PD enzyme to make sure it is safe for each individual.

    Pro-oxidant High dose IV vitamin C works extremely well for me and I'm forever grateful that my MD added it to my regimen.



  • paknc
    paknc Member Posts: 48
    edited June 2022

    Does anyone have updates from providers on the use of antioxidants and the potential for cancer metastasis? I've read a few research articles that said they may enable the motility of cancer cells, ironically, which increases the risk of metastasis. But, opinions are divided. It's very frustrating for me because I've started a few antioxidants not for cancer prevention but to help other conditions I've acquired as a result of aging, and where my diet is lacking. I take a half dose of cod liver oil because it makes a huge difference in my joint pain - there is a lot of osteoarthritis in my family tree. I used Vitamin C 500 mg, per my nutritionist's recommendation, for about 4 months to help heal esophagitis from GERD and because my diet is short of it, because I watch my blood sugar. Also, it made a positive difference in my blood sugar levels which I monitor because I've been flirting with pre-diabetes for the past 1.5 years. I haven't resumed the Vitamin C but I'd like to. Then, my vision is now deteriorating so I thought I'd try out a lutein / zeaxanthin / astaxanthin supplement for eye health, which are carotenoids, several times a week. But, now I'm reading contradictory info on how these antioxidants work - they may prevent cancer, but if you already have some roaming cancer cells, which I think we all do, they can help them become more mobile and cause metastases. I'm not going to give up the cod liver oil because it makes me feel so much better. But I"m not sure what to do about the other supplements. It seems like if I fix one thing, I break two others. :-(

  • threetree
    threetree Member Posts: 1,156
    edited June 2022

    My understanding is that with supplements it's hit and miss and there is a lot we don't know. Looks as if there is a "sweet spot" or optimal dose with a lot of these and either more or less than that optimal dose can aggravate and promote the cancer. I think researchers refer to a U shaped curve for this phenomenon. The problem is that most of us don't know just where that optimal sweet spot is for most of these vitamins and supplements. Taking "just a little" of something in case it does cause cancer, might actually be the problem, and "more is not better" and something that works at a certain dose, might be carcinogenic at a higher dose.

    The most comprehensive info I've seen so far is on the Foodforbreastcancer site. While it is mostly about food, the author has started to include info and studies on supplements. Here is a link to that page:

    Maybe you can find some helpful info there.

  • paknc
    paknc Member Posts: 48
    edited June 2022

    Great site, thanks for the info -

  • threetree
    threetree Member Posts: 1,156
    edited June 2022

    You're quite welcome. I find a lot of interesting stuff there myself and continue to refer to it off and on.