The short answer

Our bodies need oxygen in order to create energy, but this process also creates free radicals that can damage our cells. We need antioxidants to slow down the damage caused by free radicals.

The long answer

Why does the body need oxygen?

Let's start with why we need oxygen. We need constant energy to power the constant activity of our internal systems, like our heart and brain. Oxygen is a necessary molecule that our body utilizes to convert food (in the form of glucose) into energy (in the form of adenosine triphosphate, or ATP). This process is known as cellular respiration.

Why do we need antioxidants?

One of the side effects of cellular respiration is the loss of an electron from an oxygen molecule. This loose electron is referred to as a free radical, and free radicals do not like being left alone! Since electrons normally exist in pairs, a free radical will steal an electron from anywhere it can get it, causing a domino effect. Besides energy production, free radicals are also created after "exercising or exposure to cigarette smoke, air pollution, and sunlight," according to the Harvard School of Public Health.

Damage caused by free radicals can alter a cell's DNA and may lead to chronic diseases and cell damage. This is why some experts believe free radicals are responsible for our aging process.

But our bodies are not defenseless to the attack of the free radical! We can produce antioxidants, "substances that prevent the formation of free radicals, and seek and neutralize or repair the damage caused by them," as described by Sharifi-Rad et al. (2020). Antioxidants work by donating an electron to the free radical without becoming electron-stealing themselves.

Our bodies are capable of producing our own antioxidants. When we exercise we are ingesting more oxygen which leads to more free radicals, but exercise is also training our body to produce more antioxidants to fight off those free radicals. Additionally, you probably have heard of antioxidants in reference to certain foods. Consumption of antioxidant-rich foods like fruits and vegetables has been found to reduce the risk of chronic diseases.

Sources

Harvard T.H. Chan School of Public Health. (2021, March 3). Antioxidants. The Nutrition Source. Retrieved October 30, 2022, from https://www.hsph.harvard.edu/nutritionsource/antioxidants/

Sharifi-Rad, M., Anil Kumar, N. V., Zucca, P., Varoni, E. M., Dini, L., Panzarini, E., Rajkovic, J., Tsouh Fokou, P. V., Azzini, E., Peluso, I., Prakash Mishra, A., Nigam, M., El Rayess, Y., Beyrouthy, M. E., Polito, L., Iriti, M., Martins, N., Martorell, M., Docea, A. O., … Sharifi-Rad, J. (2020, July 2). Lifestyle, oxidative stress, and antioxidants: Back and forth in the pathophysiology of chronic diseases. Retrieved October 30, 2022, from https://www.frontiersin.org/articles/10.3389/fphys.2020.00694/full

Stamford, B. (2018, April 5). Free radicals, antioxidants and why you should maybe drink more red wine. Courier Journal. Retrieved October 30, 2022, from https://www.courier-journal.com/story/life/wellness/health/2018/04/05/free-radicals-antioxidants-drink-red-wine-health/483539002/