Antioxidants in Cancer: Useless?

Tuesday, May 01, 2012 Stef dela Cruz 6 Comments

It may seem like common sense that using antioxidants in cancer patients will come highly recommended. After all, healthy people benefit greatly from antioxidants, right? Wrong; the dangerous assumption that cancer may be treated with antioxidants should be corrected before it spreads like cancer – pardon the pun.

Antioxidants in Cancer

To understand the role of antioxidants in cancer therapy, let us first define what antioxidants do to the body. Below are a few important points.

  • Antioxidants prevent cancer. They do so by preventing free radical damage to cells, in turn keeping mutations to a minimum. Genetic mutations, if nor corrected, may lead to cancer cell growth.
  • Antioxidants prevent cell death. Free radicals do many things to a cell, such as disturbing the integrity of and “poking holes” in the cell membrane, making the cell prone to damage and, eventually, death. But with the help of antioxidants that fight free radicals, cells remain healthy and are more resistant to death induced by oxidative stress.
  • Free radicals aren’t all that bad. Excessive free radical activity damages cells, but some degree of free radical stress is necessary for normal body function. For instance, a study on antioxidant therapies for wound healing explains how wound healing relies on a certain degree of free radical activity.

For purposes of understanding antioxidants in cancer management, the above crash course should be enough. Now, it’s time to shed some light on the antioxidant hype.

Antioxidants in Cancer Therapy: Dangerous and Deadly?

Assuming that there will always be a role for antioxidants in cancer therapy is a little premature. After all, antioxidants protect cells – and they can protect even the cancer cells! To answer the question of whether or not antioxidants are useful in cancer management, here are a few observations based on different studies. Read on and find the answer to the question, “Are antioxidants useless in cancer treatment?

  • Some cancers benefit from specific antioxidant therapy, while others worsen with it. For instance, three natural antioxidants (acteoside, silymarin, and curcumin) enhanced the anti-cancer effects in leukemia cells, according to a 2010 study. These antioxidants enhanced the activity of AP9-cd, a substance that induces cell death in leukemia cells. However, according to the Vitamins and Lifestyle (VITAL ) cohort study, out of almost 80,000 subjects, long-term use of Vitamin A (beta-carotene, lutein, and retinol) was actually associated with a higher incidence of lung cancer.
  • The protection offered by antioxidants may extend from normal cells to cancer cells. According to an article on the antioxidant debate, this explains why excessive antioxidant use sometimes leads to a higher incidence of cancer.
  • Although there are many studies supporting the probable usefulness of antioxidants in cancer therapy, none of these studies are randomized control trials. Randomized control trials eliminate bias and are the best study design. The other studies available therefore point to a potential direction, but they do not provide definitive proof.
  • Doctors and health professionals should be very cautious in recommending antioxidants in cancer patients. There is not much research showing the usefulness and safety of all antioxidants in cancer patients. Because antioxidants may actually help protect cancer cells, prescribing antioxidant supplements should be done with prudence and discretion.
  • Antioxidant supplementation is questionable, even among healthy adults. According to a randomized control trial, long term use of antioxidants led to no improvement in the quality of life among healthy adults. Take note that this study used supplements, so its results do not apply to dietary antioxidant intake (antioxidants acquired through food).
  • The consumption of antioxidant-rich food does lead to many health benefits. Antioxidants taken in through food were related to lower blood sugar, lower cholesterol, and even a smaller waistline, based on the dietary total antioxidant capacity study.

In a nutshell, foods rich in antioxidants are definitely recommended among adults who do not have cancer. However, additional antioxidant pills (such as vitamins and health supplements) do not necessarily lead to any benefit. In addition, excessive intake of certain antioxidants (such as specific forms of Vitamin A) may lead to cancer. So, the role of antioxidants in cancer management cannot be answered by a generalization. It depends on the antioxidant, and it depends on the cancer.

Before taking any vitamin or antioxidant supplement, always consult your doctor, especially if you are undergoing chemotherapy for cancer. Antioxidants and cancer do not always make a compatible tandem. For more health updates, find me on Facebook and Twitter. You may also want to read about the cancer that mimics almost every imaginable disease. Finally, leave a comment if you have any question in mind. I can’t promise to answer every query, but I will try my best.

Stef dela CruzAbout the blogger
Stef dela Cruz is a vegan doctor and writer. She received the 2013 Award for Health Media from the Department of Health. She is the editor of The Manila Bulletin's Animal Scene Magazine. Get in touch if you want to invite her as a speaker!


  1. Oh, would you recommend vit. E daily, whether or not you have cancer, as an antioxidant?

  2. As I mentioned above, there is no generalization that applies to everyone. :) Vitamin E may be good for a certain population subset, but it can be quite dangerous for another. According to a meta-analysis by the Annals of Internal Medicine, Vitamin E is dangerous to one's health and may shorten one's life - but here's a disclaimer: this study was done mostly among old patients who might already have kidney or liver problems.

    According to Mayo Clinic, Vitamin E supplementation is dangerous if you exceed the tolerable upper intake level. But why stick to supplements if you can eat healthy food, anyway? :) If you are a healthy adult, there shouldn't be a reason for you to have no access to healthy food. Mayo Clinic has declared that Vitamin E is quite safe when you meet the daily requirements through food consumption. Actually, it's BENEFICIAL this way.

    Stop looking for the perfect vitamin supplement! Instead, look for the ideal diet. A lot of people ask me what multivitamin is best. I always tell them, "Go to the grocery, buy all the healthy food options you see: fruits, vegetables, salmon and other fatty fish, fiber-rich food, and other healthy food options - and you are going home with the best 'multivitamin' in the market." :)

  3. Great Day! I enjoy reading your post regarding antioxidants. What I would like to ask is how can a supplement with a ORAC certification of 144,500 from Brunswick Labs can affect free radicals? Also, How can 72 ionic trace minerals and Organic Germanium GE 132 be used to improve health conditions and/or lifestyle?
    Thank you

  4. Hello, Miss Pinay! Thanks for leaving a comment. Maybe you should send me several samples of those products before I can comment, hmm? Hehe, kidding!

    I clicked on your blogger profile but you don't have any blogs visible and it looks like you just signed up. And there is just one person who viewed your profile... me! I hope you didn't sign up for my sake... ;)

    Anyhow, thanks for reading my blog and enjoying my articles here!

  5. Thank you for your reply.

    Can a healthy person consume a high amount of anti-oxidants to strengthen their immmune system?

  6. Define "high". :) Moderation is key. Anything in excess may prove dangerous. And supplementation is what it is: it "supplements" the nutrition you already get from a healthy diet.

    Antioxidants in our food help us, that's for sure. But the value of taking antioxidant supplements will depend on whether you have antioxidant deficiency and on what antioxidants are actually in that food.

    Anything in excess, I repeat, can prove dangerous. Even Vitamin C, a great antioxidant that helps in tissue regeneration, can be harmful to red blood cells - causing them to rupture - if taken in excess.