By Leslie Taylor ©2025

The average American typically has some kind of basic knowledge that “antioxidants fight free radicals,” but most are unaware of exactly what a free radical is, why they need fighting, and how antioxidants work to “quench” or fight them. This article will explain the main types of free radicals, how they cause cellular damage, cellular dysfunction, and resulting illness, and the different ways specialized natural plant compounds with antioxidant actions can effectively reduce the number of free radicals in your body to promote health and avoid disease.

What Is a Free Radical?

There are two main types of free radicals: reactive oxygen species (ROS) and reactive nitrogen species (RNS). These substances are reactive because they are missing an electron. Our bodies are an oxygen-based system, as is most all life on the planet. Oxygen is an element indispensable for life. However, inside the body, some oxygen, with the help of a catalyst, splits into single atoms with unpaired electrons. Electrons like to be in pairs, so these atoms, called free radicals, scavenge the body for other electrons so they can become a pair. As they travel through the body in search of a new electron, they cause damage to cells, proteins, and DNA, and interrupt or change cellular signaling through a process called oxidation.

Consider what happens when you put a piece of untreated and unprotected metal outside in the elements or simply expose it to oxygen. Over time, the metal begins to rust. This rusting process is actually the oxidation of the metal—the chemical reaction of the metal to oxygen. ROS inside the body creates the same sort of rust-like reaction and damage as it comes into contact with unprotected cells. As another example: when the fats or oils we use to cook with are exposed to too much oxygen; over time they become rancid. The rancidity is actually oxidation of the fat molecules. When fat molecules (called lipids) in our bodies are exposed to too much ROS, they also rust or become rancid in a similar manner. For this reason, the oxygen-based free radicals (ROS) are much more damaging to our bodies, are the subject of much more research, are linked to many more diseases and conditions, and are what we will focus on in this article.

Free radicals, and specifically ROS, are a way of life. ROS are formed as a natural byproduct of the normal metabolism of oxygen, and they even play important roles in how cells communicate (called cellular signaling). Basically, free radicals are a byproduct of many different natural chemical processes going on simultaneously inside our wonderfully complex biochemical-driven bodies.

In addition to metabolizing oxygen, another large source of free radicals produced inside our bodies is the natural chemical process of how we metabolize our foods. Turning food into the cellular energy that all our cells need to function is a complex biochemical process. Free radicals are waste products generated from various chemical reactions that occur in this natural food metabolism process. Therefore, how much we eat and what we eat can be significant factors that raise our ROS levels. For example, free radicals are naturally formed each time we metabolize an ingredient in our food. Highly processed and fast foods contain many human-made chemical preservatives and additives and each ingredient will create free radicals as it is metabolized in our bodies. One popular fast-food burger chain listed 19 ingredients in their French fries, not just potatoes, oil and salt. Consider how much more ROS is generated, metabolizing all those ingredients! ROS are created inside our bodies through these natural processes, and catalyst substances in our environment can create even more ROS.

External catalysts that generate free radicals can be found in the food we eat, the medicines we take, the air we breathe, and the water we drink. These substances include fried foods, high-fructose sugars, alcohol, tobacco smoke, pesticides, exposure to X-rays, chemicals and environmental toxins, and air and water pollutants. All these substances can significantly raise the levels of ROS and free radicals in our bodies to unhealthy levels, which results in oxidative stress. The levels of internally produced ROS also increase from immune cell activation, inflammation, mental stress, excessive exercise, ischemia, infection, cancer, aging, diabetes, and obesity, which takes us over the edge of balance and into the state of oxidative stress which eventually results in cell death and organ damage. ROS can also provoke inappropriate or overexpressed immune responses and cause autoimmune conditions, activate cancer genes, mutate healthy cells into cancerous ones, and greatly increase cellular-aging processes.

What Is an Antioxidant?

In the simplest of terms, the most basic definition of an antioxidant is a substance or molecule that lends one of its own electrons to a free radical that is seeking one to make a pair. When the free radical has a new set of paired electrons, it becomes a stable molecule and is no longer reactive and causing cell damage. Remember, free radicals are radical because they are missing an electron. This process of an antioxidant lending an electron is usually called “quenching free radicals.”

Our Built-In Antioxidant System

Because ROS generation is a natural process, our bodies have a natural built-in antioxidant system that is supposed to disable these free radicals as they are created and keep them at healthy levels. This is a perfect example of one of the amazing ways our bodies maintain their delicate balance. Through other biochemical processes, our bodies produce chemicals that are the main antioxidants that make up our built-in antioxidant system. These include chemical enzymes called superoxide dismutase (SOD), catalase, glutathione peroxidase, and glutathione reductase, which are considered our first line of defense.

We also produce other substances that are non-enzyme antioxidants that participate in our built-in antioxidant system. These include chemicals we produce inside our bodies (and some of which are also sold as dietary supplements) such as lipoic acid, glutathione, L-arginine, coenzyme Q10, melatonin, uric acid, bilirubin, metal-chelating proteins, transferrin, and others.

Vitamin and Mineral Antioxidants

While these natural built-in antioxidants are main players in our antioxidant system, they need help from various vitamins and minerals that aid in the biochemical process to produce them, activate them, and help them do their job. These include vitamins A, E, and C, which we’re supposed to be getting from the foods we eat. These three vitamins are the subject of thousands of studies on their antioxidant actions and the roles they play in the body and within our antioxidant system. Of these three vitamin antioxidants, vitamin C has been shown to be the most important to the system. And, as with many antioxidants, the combination of vitamin C with either A or E has shown to have higher antioxidant actions in much of the vitamin research. Vitamin C is also uniquely able to lend not one, but two of its electrons to free radicals.

Also necessary to support our antioxidant system and its enzymes are the minerals selenium, manganese, copper, and zinc. These minerals play roles in the production and/or actions of our natural enzymes that fight free radicals. In fact, some of these minerals are capable of binding together with our enzymes, which increases their antioxidant actions and effects.

Plant Antioxidants

Plants, like humans, need oxygen to survive, and they also create their own species of reactive oxygen molecules (ROS) during their metabolism of the oxygen they breathe. For this reason, plants produce natural antioxidants in their cellular processes to keep ROS in check and at healthy levels, just as we do. These antioxidant plant chemicals are also an important component in a plant’s built-in defense mechanisms (much like our immune system) that protect the plants from damage and stress of too much or too little rainfall/moisture, too much or too little sunlight, toxic metals and chemicals in their soil, high heat, intense sunlight, high humidity, and other negative growing factors. These natural plant antioxidant compounds also help heal the damage from browsing animals and insects chewing on them (the equivalent of wounds in humans) and help plants recover from various bacteria, mold, fungi, and plant viruses that damage them. In fact, many plant antioxidants are dually antioxidant and antimicrobial—capable of killing these bacteria, virus and fungi species that try to harm them. Because plants are rooted to the ground and cannot flee from danger like we can, they create wonderfully complex biochemical defense mechanisms to fight those dangers and factors that might harm or kill them.

In addition to lending electrons, plant antioxidants can suppress the formation of ROS by inhibiting certain enzymes involved in their production. Plant antioxidants can also trigger the body’s natural production of antioxidants and send them to cells that are being damaged by oxidative stress. Much as chemical messengers signal the immune system to send healing agents to the site of an injury, plant antioxidants signal the body’s antioxidant system to send healing antioxidants to the site of oxidative stress, as well as encourage the production of more body-produced antioxidant chemicals.

Lastly, there are various metals in our bodies—including the iron circulating in our blood—that can oxidize and damage cells, much as ROS does. Some strong plant antioxidants, like those found in rainforest plants and fruits, are capable of interacting with these metals and converting the body’s metal pro-oxidants into stable products, much as they stabilize or neutralize free radicals, reducing oxidative stress.

Polyphenol Antioxidants

The main and most effective antioxidants found in plants fall into a category of well-researched defensive plant compounds called polyphenols. Scientists have long known that the polyphenols in plants can benefit humans in many of same ways they benefit, protect, and heal plants. Polyphenols, which include the subcategories of phenolic acids and flavonoids, are the subject of a huge amount of research. More than 10,000 studies on plant polyphenols have been published in just the last five years. Not only do they have very strong antioxidant actions, but because they were uniquely created to help plants heal and repair damage, their actions in humans result in these antioxidants working in different ways than vitamin antioxidants and our own natural enzyme antioxidants, which are mainly quenching free radicals through electron sharing. The healing power of these polyphenols to positively affect our health is incredible, and thankfully more health-conscious consumers are learning of their many benefits.

Remember when coffee was once supposed to be bad for you and doctors told you to avoid it, mainly because of the heart-stimulant actions of caffeine? Then, suddenly, it was good for you. The same thing happened with chocolate and wine, which once were supposed to be avoided and are now considered almost health foods. What happened? It was all the new research on the powerful health benefits of polyphenols in these two tropical plants. Coffee, chocolate (especially dark chocolate), and red wine are all significant sources of these powerful healing polyphenols. That polyphenols can overcome the negative effects of the caffeine in coffee, the high fat and calories in chocolate, and the alcohol content in wine, and still provide a net effect that is very beneficial to our health speaks to the real power of these polyphenols.

In addition to coffee, wine, and chocolate, it is the fruits and vegetables in our diets that are our main source of healthy polyphenols. Polyphenols are also found in the oils of plant seeds and fruit seeds, and this is one of the reasons why olive oil and flax seed oil are now widely consumed as “healthy oils”—they are rich in polyphenols. The polyphenol content of the foods we eat vary widely based on many factors. And like vitamin C, some powerful polyphenols are water soluble and are very sensitive to heat. The high heat generated in cooking fruits and vegetables can significantly lower the polyphenol content, which is why many nutritionists recommend having lots of raw fruits and veggies in our diets—it’s all about the powerful and beneficial polyphenols in these raw foods.

Summary

In a perfect world, we’d be getting all the vitamins, minerals, plant antioxidants, and other vital nutrients we need from the foods we eat. We’d avoid foods that generate extra free radicals, and we’d maintain a healthy weight and a healthy antioxidant system as a result. More important, in doing so, we’d be providing all the necessary nutrients all these complicated biochemical processes need that are humming along silently behind the scenes—all of which keep us healthy and avoiding problems and diseases.

But let’s face it. We don’t live in a perfect world, and we are merely imperfect humans. That kind of scenario just doesn’t describe the average American and or even the average human. I think that’s why “food supplements” and “dietary supplements” were first created and related to that kind of terminology. Many of these products really are supplementing our diets with the necessary food nutrients that are missing from the foods we eat. Other dietary supplements are helping to overcome the problems from too many of the less-than-healthy foods and lifestyle choices we can’t seem to give up.

This is why getting our daily needs of vitamin C is much better when it comes from a whole food source like the rainforest fruits camu-camu and acerola (highest Vitamin C content of all fruits on the planet), or oranges and other citrus fruits. These fruits contain a host of other beneficial natural plant compounds, including polyphenols, which naturally occur in the foods we’re supposed to be eating in our daily diet. In addition to polyphenols, fruits like acerola and camu-camu contain fatty acids, carotenoids, and other plant compounds with effective antioxidant effects. These are the compounds that aid in the absorption and uptake of the vitamins, minerals, and polyphenols in the fruit, provide synergistic actions to help vitamin C be a better antioxidant, and provide added antioxidant actions as well as host of other benefits and actions all on their own.

Go to the next article in this series to learn why rainforest plants are so powerfully healing – it’s all about the Power of Polyphenols.

© 2025 by Leslie Taylor. All rights reserved.

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