What Do Antioxidants Do?

Antioxidants are famous for their health benefits. But what do they do? Here, we’ll talk about the basics so you have a general idea of what’s going on.

Free Radicals

It’s impossible to talk about antioxidants without mentioning free radicals. Sometimes called Reactive Oxygen Species (ROS), the term “free radicals” actually simply mean unstable molecules. But generally speaking, the majority of free radicals come from the body metabolising oxygen. They then go on to damage cells and DNA, ultimately leading to disease. Some examples here:

  • Damage to eye lens
  • Inflammation of joints
  • Accelerated ageing
  • Damage to nerve cells
  • Certain cancers

Several factors affect the amount of free radicals we produce. These include the food we eat, the air we breathe, and the amount of radiation we’re exposed to. While we often say that free radicals are  bad, it really depends where you get them from. For example, exercising creates free radicals, but we wouldn’t say that exercising is bad. That’s because other things are happening during exercise.


Antioxidants are substances that can protect your cells against free radicals. A diet high in antioxidants may reduce the risk of many diseases. However, they aren’t created equal. Some have very good absorption, some can work on the brain, while some gets excreted from your body very rapidly.

Most antioxidants that you see in supplements come from plants. That’s because plants have high oxygen and sun exposure. More free radicals mean that they need more antioxidants to combat this. A similar concept is the eyes. As we spend more time staring at computer screens, our eyes get more damaged. Naturally we have defensive mechanisms for this, but it’s just not enough. To combat this, many people recommend taking lutein as it acts specifically at the eyes.

Here is a table of the different kinds of antioxidants. And as you can see, there are A LOT of categories. Some of these contain more subcategories, but you don’t need to learn all about them.

A Collection of Research Papers and Treatments: ROLE OF ...

There has been debate over the years that whether individual antioxidants work or whole foods work better. While whole foods contain a mix of antioxidants, the doses are also very small as compared to that in supplements. Some substances work better when taken in supplement form. For example, lycopene has an effect in reducing blood pressure while tomatoes obviously don’t have that effect [2].  Moreover, there’s another argument that their health benefits may not even come from their antioxidant properties at all. So it’s very hard to compare between the two and there really isn’t any reason to due to how different they are.

What About Safety?

Generally speaking, antioxidants are very safe. Many of which are also safe when consumed in large amounts. However, some particular ones to not overdose on include vitamin A, E and beta-carotene. There are concerns that these antioxidants when consumed in excess, might cause cancer if taken for long periods of time. However, these are just extreme cases of overdoses, and we don’t recommend people taking too much of anything anyway. On the other hand, vitamin A can cause birth defects in pregnancy even when it’s not overdosed. So, that antioxidant/vitamin is a special case. And that being said, it’s always a good idea to check with a professional if you should be taking a particular supplement when you’re pregnant.


  1. D. Mukesh, M. Jeevan, K. Neeraj, D. Ashok (1970). ROLE OF ANTIOXIDANT IN CANCER TREATMENT: A REVIEW. Retrieved from: http://researchandtreatment.blogspot.com/2013/09/role-of-antioxidant-in-cancer-treatment.html
  2. Mozos, I., Stoian, D., Caraba, A., Malainer, C., Horbańczuk, J., & Atanasov, A. (2018, May 23). Lycopene and Vascular Health. Retrieved from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5974099/