Ladd McNamara, M.D discusses the future of medicine both as it relates to health, supplementation, and how health professionals are finding new ways to increase income in an ever evolving world!

Should You Take Vitamins & Supplements During Chemo or Radiation Therapy?

radiation therapy ladd mcnamara blog

It is long been tradition, based upon what I call medical myth, for doctors to tell patients to stop taking nutritional supplements (vitamins, minerals, antioxidants, and omega 3 fatty acids) while undergoing chemotherapy or radiation therapy. I understand why it became tradition, but the medical evidence points to the contrary. Not only do nutritional supplements NOT interfere of chemo or radiation therapy, even better, antioxidants appear to actually help kill cancer cells, as well as prevent damage to normal cells by these toxic treatments.

Since chemotherapy and radiation therapy uses oxidative free radical DNA damage to kill cancer cells, doctors felt that antioxidants would only block the damage, making chemo and radiation less effective. That turns out not to be true. For example, radiation therapy puts out such a powerful ionizing beam of damage, to think antioxidants could prevent this DNA death ray from inflicting damage is like saying a paper bag on the train track will slow down the train.

In 2007, the journal Alternative Therapies in Health and Medicine * published a two-part article in the January/February and March/April that concluded, contrary to most doctors’ beliefs, nutritional supplements (vitamins, minerals, and antioxidants) does NOT interfere with chemotherapy or radiation treatment.

This article reviewed 50 human studies involving the use of nutritional supplements during chemotherapy or radiation therapy.   Not only were nutritional supplements, such as antioxidants, found not to interfere with cancer therapy, but in 47 of these studies nutritional supplements were associated with protection of normal cells and a reduction of side effects.

During the time I practiced medicine, and over the last 10 years since speaking throughout the world, I have heard how much better people feel if they are taking a full-spectrum vitamin, mineral, and antioxidant regimen during and/or after chemo or radiation therapy.   People do not seem to get as sick and tired if they take nutritional supplements at higher levels than a routine daily vitamin.  Cancer patients tend to get back to work faster after chemo or radiation therapy; and in many of them do not seem to drop the white blood counts as much as they do without the supplementation.

In the article cited above, 15 studies demonstrated increased survival rates among cancer patients taking nutritional supplements.

So, how and why did it become a medical myth that nutritional supplements interfere with chemo and/or radiation therapy?

In the 2007 article, the researchers stated, “A single, front-page interview in The New York Times in 1997, which was not based on published scientific work, and a single research paper involving mice, along with a press release by its author in 1999, led to the erroneous notion that vitamin C interferes with chemotherapy and radiation in humans.   This notion soon applied to all antioxidants as physicians, patients, the media, the American Cancer Society, and scores of websites took the same position without reviewing the scientific evidence.”

Although antioxidants in and of themselves help cause the destruction of cancer cells by turning on mechanisms that result in apoptosis (cellular self destruction), we have additional clues as to why nutritional supplements help enhance the killing of cancer cells with chemo and/or radiation therapy.

The authors of the two-part article explain that cancer cells take in excessive amounts of the nutrients, more so than normal cells due to  a loss of regulatory mechanisms of the cancer cells.   This loss of regulation by cancer cells decreases the amount of oxidative free radical damage required to damage cancer cell DNA.  In other words, the cancer cells become more sensitive to the chemo or radiation therapy; while at the same time the normal cells acquire protective mechanisms.

In General, Consider the Following:

A full-spectrum of essential vitamins and minerals
Fish Oil (2000 to 4000 mg/day)
Grape Seed Extract  (400 to 800 mg)
Calcium & Magnesium tablets
Co-Enzyme Q10  (200 to 400 mg)
Additional Antioxidants to Consider:

Turmeric Extract (curcurmin)
Alpha Lipoic Acid
Green Tea Extract
N Acetyl L-Cysteine (a precursor to glutathione)
Olive Extact (100 to 200 mg)


There are many other great antioxidants, but the above will give a general idea of what people can do while undergoing chemo or radiation therapy. However, in my opinion being on the basic foundation of nutritional supplements is critical for everyone, let alone people being exposed to such toxic treatments.

*  References:
Altern Ther Health Med. 2007 Jan-Feb;13(1):22-8.
Altern Ther Health Med. 2007 Mar-Apr;13(2):40-7.

Note: Nutritional supplements and antioxidants referred to in this study were typical vitamin/mineral/antioxidant supplements, and did not include herbal treatments or products.   The information provided here should not be used to replace the advice of the physician.  It is intended to be an aid in discussion with the health care specialist regarding appropriate use of nutritional supplements during cancer treatment.



Posted On
Mar 21, 2012
Posted By
Scott LaPointe


Thanks for the information on taking supplements during chemo. Perfect timing for the post. I enjoyed reading and learning from it! Keep up your great work. It benefits so many people.


Posted On
Mar 21, 2012
Posted By
Ladd McNamara, M.D.

Scott, I’m so glad that your oncologist looked at the USANA and allowed you to take it during your chemotherapy. I appreciate your comments, and glad to know more and more doctors are understanding the benefits of high-quality nutritional supplements.

Posted On
Apr 09, 2012
Posted By

I am scheduled to start radiation treatment for early stage breast cancer in 2 weeks. After much time researching, I have put myself on a routine of high quality supplements. I feel great, my energy is better than ever and I am soooo glad to read what my gut instinct tells me to do…..keep taking the supplements. I am using fish oil, calcium plus (Pure Essence Labs) and a very good food based multi, liquid Coq10, and it D. Did I miss anything? Should I be using anything else? Thank You for this timely article.

Posted On
Apr 09, 2012
Posted By
Ladd McNamara, M.D.

Best of health to you on your journey. In addition to what you’ve listed, I would also suggest to my patients in your situation to consider a pure grape seed extract (around 600 to 800 mg per day), 30 mg of resveratrol, as well as curcumin (a.k.a., turmeric extract), on the order of 400 to 800 mg/day. Also, mikl thistle extract, alpha lipoic acid, N-acteyl-L-cysteine, olive fruit extract, green tea extract, and vitamin D (4000 to 6000 IU/day); …and there are more! Many of these supplements are found in the products I take, and have recommended to my patients. Please see

Posted On
Mar 30, 2013
Posted By
Andrik Schapers

Dear Dr Ladd,

Thank you so very much for exposing this anti oxident fairy tale
And thank you for your generous sharing of your valuable data.
My wife was worried about me combining alternative and chemo
And this handled it for her.
I am doing great with rhe combining very little negative effects
And it helps a lot. Thanks again lots!!!!! Andrik Schapers

Posted On
Aug 01, 2013
Posted By
Brenda Tyner

My brother had a lump on his neck went into surgery they removed his tonsils and found cancer. He is now going through kemo and radiation. Its only been a week has 6 more to go he has lost 10lbs weighs only 140 has no energy and getting worse. Was thinking of vitamins to help boost his energy and because he isn’t eating will have to have a feeding tube put in when his throat closes from the radiation can some one please help me in helping him stay heathy as much as possible . Very worried about him and can’t loose another family member to cancer (mom)

Posted On
Aug 30, 2013
Posted By
brian bohlke

thanks for the info Dr Ladd! You help so many people! Thanks!

Posted On
Sep 26, 2013
Posted By
Tanya Blanchard

Hi there…
I am so grateful to have stumbled upon your website….my mom was just diagnosed with stage 4 colon/bowel cancer….she is only 90 lbs. and was also diagnosed a few years ago with early stage parkinson’s disease….she is very scared and so am I….she is not ready to go and I am not ready to see her go…she is 66 years old…I don’t agree with chemo and wanted her to take an alternative approach but when you hear the words 4-6 months without treatment and up to 23 months with treatment you want to grab at the longest time frame and believe what the doctors tell you (chemo)…I put her on a raw food diet last week and bought her a juicer, lots of organic veggies, few fruits, lots of nuts and am trying to follow a high alkaline diet to promote oxygen as her PH is very acidic….I wrote down all the supplements that you suggested like full spectrum vitamins, fish oil, grape sea, calcium, magnesium, co enzyme, turmeric, alpha lipoic, green tea, N Acetyl, olive extract but I really need to know if there is anything else that I can do to boost her immune system quickly and give her a fighting chance before chemo starts next week….please help with any advice and I am very grateful….


Posted On
Sep 26, 2013
Posted By
Tanya Blanchard

p.s. she went to chemo consultation today and they told her not to take certain vitamins and so they don’t interfere….I told her not to believe it and not to tell them anything either….is that okay?

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Information on this web site is provided for informational purposes only. The information is a result of years of practice experience and study by the author. This information is not intended as a substitute for the advice provided by your physician or other healthcare professional or any information contained on or in any product label or packaging. Do not use the information on this website for diagnosing or treating a health problem or disease, or prescribing medication or other treatment. Always speak with your physician or other healthcare professional before taking any medication or nutritional, herbal or homeopathic supplement, or using any treatment for a health problem. If you have or suspect that you have a medical problem, contact your health care provider promptly. Do not disregard professional medical advice or delay in seeking professional advice because of something you have read on this web site. Information provided on this web site and the use of any products or services purchased from this website (or as a result of information provided this website) by you DOES NOT create a doctor-patient relationship between you and any of the physicians or authors affiliated with this website. Information and statements regarding dietary supplements have not been evaluated by the Food and Drug Administration and are not intended to diagnose, treat, cure, or prevent any disease.