Q & A Library

Print this page | Sign up for free e-bulletins
 | Bookmark This Page

Downside of Antioxidants?

Can you take too many antioxidants?

Answer (Published 10/14/2010)

Antioxidants are compounds that help protect the body. They do this by blocking the oxidation reactions that harm the molecules of cells and tissues. Just as oxygen can cause metals to rust and corrode, it (and other oxidizing agents) can pull electrons from organic molecules, rendering them defective. Especially dangerous are free radicals, electronically unstable atoms or molecules generated in the course of normal metabolism that can initiate chain reactions of oxidative damage. Cumulative damage of this sort probably accounts for many of the degenerative changes of aging and contributes to age-related disease.

Related Weil Products
Dr. Weil's Vitamin Advisor for Supplements & Herbs - If you are interested in supplementing your diet, and want to take the mystery out of choosing vitamins, try Dr. Weil's Vitamin Advisor. Visit today for your free, personalized Dr. Weil's Vitamin Advisor Recommendation.

Vitamins C and E are capable of "quenching" free radicals by donating electrons to them. Other micronutrients that act as antioxidants are the mineral selenium and the carotenoid pigments in fruits and vegetables.

You do have to be careful when choosing antioxidant supplements. Vitamin C, for example, is most needed in the liquid contents of cells, near the respiratory "factories" - the mitochondria - that spew out free radicals. But when you take vitamin C as a supplement, it mostly stays in the bloodstream and extracellular fluid. This is less of a concern with vitamin E, which is fat soluble and acts mainly to protect the fatty layers of cell membranes from free-radical chain reactions, but where a compound has its effects can be a concern for many of the antioxidants taken as supplements.

Vitamin C can function as a pro-oxidant as well as an antioxidant. Under some circumstances it can accept electrons from another molecule rather than donate electrons to quench a free radical. If you flood the system with more vitamin C than you normally get from fruits and vegetables in the diet, you do not know which action will predominate. It would be most unwise to add to the body's oxidative stress by giving it more than it needs in the form of dietary supplements.
Supplemental beta-carotene is another example. In smokers and former smokers, it seems to act as a pro-oxidant, increasing their risks of developing lung and colorectal cancers, rather than protecting them, as we once thought.

My advice is to stick with the antioxidant supplement doses I recommend. But there's no need to limit the amount of fruits and vegetables you consume, or be concerned about getting too many antioxidants from them.

Andrew Weil, M.D.

Creative Commons License Some Rights Reserved Creative Commons Copyright Notice
A portion of the original material created by Weil Lifestyle on (specifically, all question and answer-type articles in the Dr. Weil Q&A Library) is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 United States License.

The Weil Vitamin Advisor
Get your FREE personalized vitamin recommendation & supplement plan today!

Dr. Weil on Healthy Aging
Your Online Guide to the Anti-Inflammatory Diet. Start eating for your health - begin your free trial now.

Dr. Weil's Spontaneous Happiness
Achieve emotional well-being in just eight weeks! Start your 10-day free trial now!

Vitamin Library
Supplement your knowledge with Dr. Weil's essential vitamin facts. Learn why they are necessary and more.

Dr. Weil's Optimum Health Plan
Your 8-week plan to wellness.
Begin your journey today!

Dr. Weil's Head-to-Toe Wellness Guide
Your guide to natural health.
Use the Wellness Guide today!

Dr. Weil's Anti-Inflammatory Diet
Food Pyramid

Our interactive tool can help improve overall health through diet.

Condition Care Guide
Learn about health conditions from acne to vertigo, and Dr. Weil's view of the best treatment options for each.

Healthy Recipes
Discover a treasure trove of healthy, healing foods and creative, delicious ways to prepare them.

Q&A Library
Over 2,000 questions from you and their corresponding answers from Dr. Weil.

Copyright © 2015 Weil Lifestyle
Information on this web site is provided for informational purposes only and is not intended as a substitute for the advice provided by your physician or other healthcare professional. You should not use the information on this web site for diagnosing or treating a health problem or disease, or prescribing any medication or other treatment.

Ad Choice
Advertising Notice

This Site and third parties who place advertisements on this Site may collect and use information about your visits to this Site and other websites in order to provide advertisements about goods and services of interest to you. If you would like to obtain more information about these advertising practices and to make choices about online behavioral advertising, please click here