Letters from Our Readers
September 08, 2008
Web Exclusive: For the Caregiver: How to Make the Adjustment Post-Treatment
September 08, 2008 – Charlotte Huff
Defeating Fear: Strategic Moves
September 08, 2008 – Paul Engstrom
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September 08, 2008 – Tara Beers Gibson, PhD
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September 08, 2008 – Kathy LaTour
Re-Entry: Age & Gender
September 08, 2008 – Charlotte Huff
Web Exclusive: How to Manage Side Effects
September 08, 2008
Web Exclusive: Preventing Breast Cancer
September 08, 2008
Breaking Down TCM
September 08, 2008 – Lena Huang
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September 08, 2008 – Joanne Kenen
Survivors Celebrate and Stroll
September 08, 2008 – Lena Huang
Active Recovery
September 08, 2008 – Don Vaughan
Challenges in Cancer Survivorship
September 08, 2008 – Kathy LaTour
Back to 'Normal'
September 08, 2008 – Charlotte Huff
Web Exclusive: Questions to Ask Your Doctor
September 08, 2008
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September 08, 2008 – Jeffrey Belkora, PhD
Multiple Myeloma & Thrombocytopenia
September 08, 2008 – Elizabeth Whittington
The Last Tenth
September 08, 2008 – Jen Hoffmann
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September 08, 2008 – Lacey Meyer
Glossary: Making Sense of the Jargon
September 08, 2008 – Katy Human
Surgery & Radiation: New Options, New Questions
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To Take or Not to Take
September 08, 2008 – Lena Huang
Finding Your Compass
September 08, 2008 – Katy Human
Pretty Is What Changes
September 08, 2008 – Kathy LaTour
Dana Farber's Survivorship Clinic
September 08, 2008 – Elizabeth Whittington
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New Funding and a New Voice
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Advocating for Others
September 08, 2008 – Lacey Meyer
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Q&A: Vitamin D
September 08, 2008 – Len Lichtenfeld, MD
www.SharingHope.tv
September 08, 2008 – Elizabeth Whittington
New Pharmacy Breed Offers Special Attention, Drawbacks to Patients
September 08, 2008 – Jessica Wapner
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September 08, 2008 – Elizabeth Whittington
International Thyroid Cancer Survivors' Conference
September 08, 2008 – Elizabeth Whittington
Understanding Preventive Mastectomy
September 08, 2008 – Kathy LaTour
New Law Prevents Genetic Discrimination
September 08, 2008 – Elizabeth Whittington
East Meets West
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Facing A Legacy
September 08, 2008 – Kathy LaTour
What to Know Before You Go
September 08, 2008 – Susan Kreimer
Far From Home
September 08, 2008 – Susan Kreimer
Message from the CURE Staff
September 08, 2008 – The CURE Team
Letters from Our Readers
September 08, 2008
Web Exclusive: For the Caregiver: How to Make the Adjustment Post-Treatment
September 08, 2008 – Charlotte Huff
Defeating Fear: Strategic Moves
September 08, 2008 – Paul Engstrom
Scott's Denial
September 08, 2008 – Tara Beers Gibson, PhD
Planning for Survivorship
September 08, 2008 – Kathy LaTour
Re-Entry: Age & Gender
September 08, 2008 – Charlotte Huff
Web Exclusive: How to Manage Side Effects
September 08, 2008
Web Exclusive: Preventing Breast Cancer
September 08, 2008
Breaking Down TCM
September 08, 2008 – Lena Huang
When Patients Don't Want to Know
September 08, 2008 – Joanne Kenen
Survivors Celebrate and Stroll
September 08, 2008 – Lena Huang
Active Recovery
September 08, 2008 – Don Vaughan
Challenges in Cancer Survivorship
September 08, 2008 – Kathy LaTour
Back to 'Normal'
September 08, 2008 – Charlotte Huff
Web Exclusive: Questions to Ask Your Doctor
September 08, 2008
What's the Right Decision?
September 08, 2008 – Jeffrey Belkora, PhD
Multiple Myeloma & Thrombocytopenia
September 08, 2008 – Elizabeth Whittington
The Last Tenth
September 08, 2008 – Jen Hoffmann
Keep It Moving
September 08, 2008 – Lacey Meyer
Glossary: Making Sense of the Jargon
September 08, 2008 – Katy Human
Surgery & Radiation: New Options, New Questions
September 08, 2008 – Katy Human
Currently Viewing
To Take or Not to Take
September 08, 2008 – Lena Huang
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September 08, 2008 – Kathy LaTour
Dana Farber's Survivorship Clinic
September 08, 2008 – Elizabeth Whittington
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September 08, 2008 – Elizabeth Whittington
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September 08, 2008 – Elizabeth Whittington
Advocating for Others
September 08, 2008 – Lacey Meyer
Never Fear
September 08, 2008 – Paul Engstrom
Q&A: Vitamin D
September 08, 2008 – Len Lichtenfeld, MD
www.SharingHope.tv
September 08, 2008 – Elizabeth Whittington
New Pharmacy Breed Offers Special Attention, Drawbacks to Patients
September 08, 2008 – Jessica Wapner
Olympian Postpones Treatment to Compete
September 08, 2008 – Elizabeth Whittington
International Thyroid Cancer Survivors' Conference
September 08, 2008 – Elizabeth Whittington
Understanding Preventive Mastectomy
September 08, 2008 – Kathy LaTour
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September 08, 2008 – Elizabeth Whittington
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September 08, 2008 – Lena Huang
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September 08, 2008 – Kathy LaTour
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September 08, 2008 – Susan Kreimer
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Message from the CURE Staff
September 08, 2008 – The CURE Team

To Take or Not to Take

Role of antioxidants called into question -- again. 

BY Lena Huang
PUBLISHED September 08, 2008

Scientists have long investigated the connection between antioxidants and cancer, and now a new study reported in the Journal of the National Cancer Institute concludes that cancer patients undergoing radiation or chemotherapy should avoid routine use of antioxidant supplements. 

With about 60 percent of cancer patients reporting that they take some type of vitamin supplement, according to the American Cancer Society, the relationship between antioxidants and cancer begs for clarity.

The debate is complex because a variety of antioxidants exists, not only in food and in supplements but also manufactured by the body. Combine that with the number of cancer therapies, cancer stages, tumor types, and other variables, and it is no wonder there are varying opinions on the topic.

For the JNCI study, researchers combed through two decades of clinical trials that had concurrent administration of antioxidant supplements with chemotherapy or radiation. They found three randomized studies focused on radiation and 16 on chemotherapy. While some of these studies showed antioxidant benefits, such as a reduction in side effects, others showed a decrease in survival rates of cancer patients.

With these varying assumptions, Brian D. Lawenda, MD, lead investigator of the study, said his team based their conclusion on the physician’s dictum of “first, do no harm,” that in the absence of beneficial evidence, doctors should advise against the use of high-dose supplemental antioxidants during radiation and chemotherapy until further studies are done.

Antioxidants are substances that block oxidation and affect many processes. One role they have is protecting cells from free radical damage. Free radicals (highly reactive molecules produced during normal metabolism and by environmental toxins) damage DNA, a reaction that may cause certain genes (the parts of DNA that encode proteins) to develop mutations, which can initiate new cancer cells or promote the growth of existing ones.

Many chemotherapy agents and radiation therapies work by inducing free radicals that damage cancer cell DNA and proteins. And while this can harm normal cells, it causes even more damage to rapidly growing cancer cells. So taking large doses of antioxidant supplements may interfere with these therapies by reducing their anticancer activity, according to Lawenda’s study.

However, Lawenda, who is also the clinical director of radiation oncology at Naval Medical Center San Diego, adds that patients should not interpret this conclusion to mean they should remove foods with antioxidants from their diets. “Importantly, the potential adverse consequences of antioxidant supplements may be related to the high doses in which they are administered—intakes which cannot be easily achieved by any diet rich in these plant foods.”

Some commonly known natural antioxidants are vitamin C, which is found in citrus fruits and blueberries, and beta-carotene, which is found in carrots and other orange foods. These antioxidants and others have been studied in large-scale clinical trials since the 1980s with some showing promise and others revealing increases in cancer rates.

More recent research derived from cell culture and animal studies suggests antioxidants may slow or prevent cancer. “There are numerous reports that chemopreventive agents derived from natural sources—fruits, vegetables, spices—have antioxidant activity and are beneficial,” says Bharat B. Aggarwal, PhD, professor of experimental therapeutics at M.D. Anderson Cancer Center in Houston.

Aggarwal has studied numerous agents in fruits and vegetables, such as curcumin (a spice), lycopene (found in tomatoes), and resveratrol (found in grapes), that target specific molecular actions that can have preventive effects on cancer and other diseases.

Until further studies on specific antioxidants and cancer outcomes are done, Lawenda recommends patients get a natural mix of antioxidants through food sources as specified through the federal government’s dietary guidelines (www.health.gov/dietaryguidelines).

“We recommend that patients continue to meet the established dietary requirements [set by the government] for the essential vitamins C and E and the intake of carotenoids, flavonoids, and related antioxidant phytochemicals,” Lawenda says.

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