What Do Antioxidants Do? And Why Are They Important?

You’ve been told that you should eat more blueberries, kale, and green tea because they’re antioxidant super foods. But what do antioxidants do, exactly?

what do antioxidants do

What do antioxidants do, why are they important, and where can you find them?

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You may already be supplementing your diet with antioxidant-rich foods and supplements like berries, green leafy vegetables, and more. But do you actually know what an antioxidant is? What do antioxidants do? To give you a better understanding of how these disease-fighting compounds keep you healthy, let’s start with a discussion of free radicals and oxidative stress.

What Are Free Radicals?

Free radicals are highly unstable molecules produced naturally as a byproduct of chemical reactions in our cells and also when we are exposed to toxins. Free radicals are formed when the food we eat is converted into energy, when we exercise, and when we are exposed to things like sunlight, cigarette smoke, radiation, or pollution.

Electrons typically come in pairs. Free radicals contain unpaired electrons, which is what makes them so unstable; they will wreak havoc to steal the electrons they need from other molecules. In doing so, they can cause significant damage to cells in the body and can set off chain reactions of what is termed oxidative damage and oxidative stress.

Once one free radical is formed, it creates a domino effect, creating many more free radicals as a result.

The Effects of Oxidative Damage

Free radical formation is normal. Plants, animals, and humans produce free radicals all of the time. Our bodies have defenses against free radicals, but when the strength of these defenses are outweighed by the amount of free radicals themselves, they can cause lasting harm, and even cell death.

Oxidative stress on the body can damage DNA, leading to cancer; compromise cell walls, allowing substances into the cell that aren’t supposed to be there; and make LDL-cholesterol stick to blood vessels, causing atherosclerosis.

Oxidative damage has been linked to several diseases, including cardiovascular disease, Alzheimer’s disease, and cancer.[1,2] So how can you help your body to prevent these devastating effects of free radicals and oxidative damage? The answer lies in antioxidants.

What Do Antioxidants Do?

Antioxidants come in many different shapes and sizes, but the quality they all share is that they are able to neutralize free radicals, preventing them from damaging the body. They often act by donating electrons to free radicals, making them more stable. They also can degrade free radicals, rendering them harmless.

Whatever the mechanism it uses, an antioxidant helps protect the body from damage by interrupting the deleterious effects of free radicals and the chain-effect of oxidative damage that they cause. In essence, the benefits of antioxidants are to properly detoxify the body of these harmful molecules.

Researchers are continuously learning more about how oxidative stress plays a role in the development of many diseases and age-related conditions, and how antioxidants might help to prevent them. Antioxidant intake may be protective against dangerous diseases such as ­­­cancer, cardiovascular disease, and neurodegenerative diseases like Parkinson’s and Alzheimer’s.[1,2]

Some antioxidants, such as the compound glutathione, are produced by the body to naturally defend against oxidative stress. Others we get through diet, such as vitamin C and vitamin E.

There are numerous foods with antioxidants that benefit our health, including polyphenols from berries, carotenoids from sweet potatoes, resveratrol from grapes, and more. Oftentimes, the most colorful foods have the most potent antioxidants.

Now that you know why antioxidants are so important to your body, be sure to keep loading up your plate with foods high in antioxidants such as fresh berries, green leafy vegetables like kale, green tea, vitamin C rich bell peppers, vitamin E rich sunflower seeds, and other antioxidant powerhouses such as artichokes, dark chocolate, pomegranates, cinnamon, and nuts.

Share Your Experience

What are antioxidants that you like to incorporate into your diet? What are your favorite antioxidant foods? Do you have any experience with antioxidant supplements? Share your tips in the comments section below.

Originally published in 2015, this post has been updated.


[1] Biomed Res Int. 2014;2014:761264.

[2] Food Chem Toxicol. 2015 Feb 16;80:72-79.

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  • Folks, you and I have for a long time been misled to believe that plant antioxidants cause the mitigation of our health challenges. IT WAS and IS STILL a very WRONG indoctrination.
    There has been enough research and insight into the fact that the plant world’s, and human and animal world’s antioxidants are completely different in chemical structure. That makes the plants’ versions toxic to us. Plant and human antioxidants do not even have the same names.
    The liver does not recognize the plants’ version and works hard quickly to eliminate them from the body. If you have a weak liver it may not be able to do that so well. They are sent back into the increasingly more “dirty” bloodstream. That in part causes feelings we call “side effects” because these toxins could irritate other weak body areas and do erosive damage. This results in vitamin, mineral, enzyme, etc. depletion and malfunction and dis-ease/ illness. YOU WILL FEEL BAD!
    WHAT NEEDS TO BE UNDERSTOOD CORRECTLY however is that these, foreign-to-our-bodies, xenobiotics-plant antioxidants are toxic to us. But that is in our favor when we understand the concept of HORMESIS. This basically means: as with the large amounts of “antioxidant” content of pills, “a little bit will do ya (good), a lot will (could) screw ya (royally)”.
    The ROS antioxidant effect rating often lauded for a plant food, indicates how strong its toxicity and nasty taste is to hungry attacking animals, birds and bugs. Their antioxidants are for the plant’s survival.
    The health concern to humans is that the suppression of the ROS (Reactive Oxygen Species) in the human body with artificially made, or excessive plants’ ANTI-oxidants prevents the process of APOPTOSIS (= necessary programmed self-induced death of our aging cells). Doing that then allows our cells to not die properly and instead mutate (change) and proliferate in an uncontrolled tumor manner. And we know what that is then called: cancer and / or other serious healthiness discomforts.
    Given enough time and involving many, many other factors, i.e. stress of all sorts, the above process stops our immunity abilities from ending their wayward activities.
    The process of apoptosis REQUIRES OXYGEN. Repeated swallowing high doses of artificial ANTIoxidant (= antiOXYGEN) pills therefore invites problems.
    WHAT IS CORRECT TO SAY however is that eating reasonably healthy plant foods (and their toxins which tend to make them sometimes BITTER) activates in us certain appropriate biochemical “pathways”. It is via these protective and necessary pathways that, in a healthy body AND WITH A HEALTHY LIVER, we stimulate the production of our own important and necessary antioxidants. Glutathione is the most important one made by all cells and the liver. Eating regularly (daily) some foods which are bitter is part of an intelligent health promoting practice.
    I am your friend: Dr Pieter Dahler, DDS, MD, ND (hon Professor), Ph.D

  • Thank you for your comment!

    We certainly agree that anything in excess, even antioxidant supplements, can be harmful to the body. But many people do not eat enough of the antioxidant-rich foods described in this blog and could benefit from higher intake.

  • It’s true that phytochemicals, even those that have specifically been shown to promote longevity and help protect against cancer and other chronic diseases, can have both pro-oxidant and antioxidant effects in different tissues in the body. However, the fact of the matter is that many phytochemicals have been shown to protect against oxidative stress in humans, while at the same time helping to destroy cancer cells, in part because of their pro-oxidative/apoptosis-inducing effects in cancer cells. Taking high doses of certain phytochemicals in supplement form has also been shown to have clinically significant therapeutic effects in well-controlled trials for a number of different health conditions. However, that does not mean that some people, such as those with liver disease or poorly functioning detoxification systems, may not be able to tolerate high-dose phytonutrient supplements.

    Dr. Kathleen Jade

  • Hi! This is such an informative, helpful piece. Thank you for sharing your knowledge of antioxidants and the crucial role it plays in the body. It is very easy to understand! However, I think you missed to elaborate on the best food sources for antioxidants, which is some beneficial information, especially for those who are looking to boost their health through their diet. More power to you!

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