Antioxidants: How They Work and Why You Need Them

What is an antioxidant?

To answer this question, we need to first learn what an “oxidant” is. Oxidants are anything that causes the body oxidative stress, which is damage to the cells. A build-up of free radicals can lead to oxidative stress.

Free radical formation occurs naturally in the body from regular activities like eating and exercising. A free radical is an unpaired electron. Atoms can bond with other atoms to make molecules through sharing electrons. When a molecule has an unpaired electron, it is a very unstable molecule.

To restore chemical stability, the unpaired electron needs to find a partner. If there is no partner around, damage to cells, or other stable molecules, can occur. We don’t want to chemically damage parts of the body that work properly. To prevent this damage from happening, you’ll want to consume antioxidants. An antioxidant is a substance found in highly colored fruits and vegetables. The chemical makeup of the antioxidants are what make them special and able to do their job.

If you look at the figure below, you can see many hexagons with double lines through them on three sides. In organic chemistry, we represent carbon-carbon bonds as lines like this. The hexagons are representative of 6 carbon atoms attached in a ring, with the double lines representing double bonds, which are stronger than the single carbon-carbon bonds.

Tannic acid - Wikipedia
Figure. Chemical structure of tannic acid – a compound found in tea leaves and other plants. It’s a type of polyphenol. with antioxidative properties.

A double bond that is repeated over a long distance, like you see above, in a molecule is what gives substances their color. Some substances aren’t colored, so they don’t contain very many double bonds. However, highly colored plants, fruits, and veggies all contain double bonds and/or ring structures like the one above! Berries, like the ones below, are a good source of antioxidants… can you guess why?

Why do you need antioxidants?

Like I mentioned above, our bodies normally experience oxidative stress. We can’t help that our body creates free radicals, because we have to eat and exercise. However, there are also other free radicals that we can be exposed to through our environment. While we can’t help that we are either producing or being exposed to antioxidants on a daily basis, we can control the types of foods that we eat.

Eating foods that are highly colored like fruits and leafy greens can help us combat the oxidative stress that leads to cell damage. As a chemist, it’s such a cool concept to think about. These foods contain compounds that are able to trap the free radicals, preventing them from reacting with and potentially damaging other parts of your body!

High levels of oxidative stress are linked to an array of diseases… but does supplementing with antioxidants guarantee that you will be disease-free?

What about the science behind antioxidant supplementation?

So far, it looks like the only antioxidants studied in depth have been Vitamin E, Vitamin C, and beta-carotene (a form of Vitamin A). These have been studied because these are the vitamins that people typically supplement with for disease prevention. It was actually found that these specific antioxidants (when used alone as a supplement) either had no effect on disease prevention or actually made certain conditions, like bleeding from current disease, worse.

Please read carefully. The studies completed that produced these results were on specific compounds (Vitamins E and C and beta-carotene). The form of antioxidants that the participants used in the study were not in the state that they are naturally found. Does this mean that we shouldn’t supplement with antioxidants? Maybe… but don’t cancel them just yet.

There were many confounding variables that led to these results, and more research is still needed. Surprise, surprise. Many of the research participants were already at high risk for disease. Additionally, the antioxidants used in the studies were not the naturally-occurring antioxidant found in foods. For instance, the researchers isolated one form of Vitamin E, when in reality, EIGHT forms of Vitamin E exist naturally in foods.

So… what should you do? Well… I will revert to my default answer. Get as many as your nutrients, antioxidants included, from whole foods. When whole foods alone cannot satisfy your nutritional needs, then you can consider using a supplement. As for me personally, I take a reds powder that is made up of highly colored fruits to add to my whole food diet. It’s from natural sources, and not lab-made like the ones mentioned above. I don’t have any pre-existing conditions, and I am not at a high risk for any one disease, so I feel comfortable taking it, knowing that I am potentially combating oxidative stress from all of the exercising and eating that I do!

P. S. In case you were wondering, yes, wine does contain antioxidants. However, the damage that you are doing to your body by drinking alcohol far outweighs the benefit of consuming the antioxidants in the wine. It’s okay to consume wine, but you shouldn’t replace your fruits and veggies with a glass of wine!!!


Chun OK, Floegel A, Chung SJ, et al. Estimation of antioxidant intakes from diet and supplements in U.S. adults. Journal of Nutrition. 2010;140(2):317–324.

Cook NR, Albert CM, Gaziano JM, et al. A randomized factorial trial of vitamins C and E and beta carotene in the secondary prevention of cardiovascular events in women: results from the Women’s Antioxidant Cardiovascular Study. Archives of Internal Medicine. 2007;167(15):1610–1618.

Nakayama A, Alladin KP, Igbokwe O, White JD. Systematic review: generating evidence-based guidelines on the concurrent use of dietary antioxidants and chemotherapy or radiotherapy. Cancer Investigation. 2011;29:655–667.

Lin J, Cook NR, Albert C, et al. Vitamins C and E and beta carotene supplementation and cancer risk: a randomized controlled trial. Journal of the National Cancer Institute. 2009;101(1):14–23.

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