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You can’t escape talk (and marketing!) of antioxidants. From skin creams to nutritional supplements, antioxidants are constantly touted as a miracle cure for everything from looking younger to reversing chronic disease.

But what exactly is an antioxidant?

How does it really contribute to your health?

And most importantly, what is the best way to get your antioxidants—diet, supplements or both?

Let’s tackle these questions and more.

Antioxidants and Free Radicals

Antioxidants prevent and repair the damage caused by free radicals in the body. To fully understand antioxidants we need to understand what is a free radical.

Free radicals are metabolic (waste) products that form when the body turns food into energy. They can also be created by your body’s immune system to fight an infection or as a response to environmental agents such as stress, air pollutants, radiation, cigarette smoking, drugs or other chemicals. Both inevitable and inescapable, free radicals become problematic when they are produced in quantities greater than the body can handle.

Free radicals come in a variety of shapes, sizes and chemical configurations but they all share one thing in common which is a hunger for an extra electron. Free radicals are chemically unstable and react with nearby molecules to ‘steal’ this extra electron (to gain stability), altering the structure and function of those molecules. The “attacked” molecule loses its electron and becomes a free radical itself, which starts a cascade reaction that ultimately results in damage to cells. For example, free radical damage can harm your DNA resulting in mutation into cancerous cells.   It can also increase the likelihood that LDL (otherwise known as a ‘bad’ cholesterol) gets trapped in an artery wall. It is therefore hardly surprising that free radicals have been linked to a number of chronic diseases including cancer, strokes and heart disease.

What Exactly Is an Antioxidant Anyway?

Antioxidants are one of the body’s biggest lines of defense against free radicals. Antioxidants fight free radicals by ‘giving’ one of their own electrons to the free radicals without becoming free radicals themselves. Simply put, an antioxidant is not a substance, but a chemical property, i.e. it acts as an electron donor.

All antioxidants are not created equal. What is interesting is that some substances that act as antioxidants in one situation can very well be pro-oxidants (i.e. electron grabbers) in a different situation. It is also important to note that each antioxidant has unique chemical behaviors and biological properties. No one antioxidant can therefore do the work of the whole crowd.

There are hundreds—even thousands—of substances that act as antioxidants. The most familiar ones are Vitamin C, Vitamin E, beta-carotene, selenium and manganese. Less known but equally as powerful are flavonoids, phenols, polyphenols, phytoestrogens and many more!

How Can We Get Our Antioxidants?

Our bodies can create their own antioxidants, but we also need to take in additional antioxidants from our food. The absolute best sources for this are plants. Antioxidant foods originate from the plant kingdom and thousands of compounds with high antioxidant activity are found naturally in plant foods. In fact, plant foods have 64 times more antioxidant activity than animal foods on average!

An 8-year Norwegian study measured the antioxidant activity of 3100 foods in over 23 different categories. The top antioxidant sources are berries, green and herbal teas, herbs, nuts, seeds, spices and vegetables.

A recent study solidifies the evidence that a plant-based diet is undoubtedly the best place to source your antioxidants. The research, which covered a half million people and analyzed total dietary antioxidants and their effect on the risk of stomach cancer, demonstrated clearly that intake of different sources of plant foods is associated with a reduction in stomach cancer risk.

It’s Not Just What You Eat, but How You Eat It

But it’s not just what you eat (i.e. lots of fruit and veggies!) but how you eat them.   Specifically, it is important that your antioxidants are eaten at each meal. The reason is that free radicals are produced each time our body assimilates food. You can’t just eat a bowl of berries at breakfast and expect to effectively combat free radicals throughout the day. A much better way to combat the damages of free radicals is to ensure that each of your meals contains high antioxidant foods.

Why Antioxidant Supplements Don’t Work

Interestingly, while a whole food plant-based and antioxidant rich diet appears to have a considerable positive effect in staving off chronic disease, studies of antioxidant supplements do not show the same results. In fact, there is mounting evidence that bottled antioxidants may do more harm than good.  A recent review analyzed over 200,000 healthy people and 81,000 with various diseases and concluded that there is ‘no evidence to support the use of antioxidant supplements either in the general population or in patients with various diseases’.

One explanation is that high doses of isolated vitamins could very well cause disturbances in our body’s natural antioxidant network. Antioxidants in plant foods don’t act in isolation; they work synergistically and are therefore much more effective.   To really combat the ill effects of free radicals, many different antioxidants are needed; it is foolhardy to imagine that a few artificially isolated antioxidants could ‘fix’ things.

Antioxidants are essential soldiers in the ongoing battle between your body’s healthy cells and the cancer-causing free radicals in your body. However, you are best served sourcing those antioxidants from a diverse whole food plant-based diet—berries, whole grains and a variety of vegetables—rather than an expensive bottle of supplements.

At the end of the day, Mother Nature just can’t be put into a bottle.

Rosane Oliveira, DVM, PhD

President & CEO, Plant-Based Life Foundation | Dr. Rosane Oliveira combines a lifelong passion for nutrition with 25 years of genetics research to create programs that help people develop healthy habits on their journey towards a more plant-based lifestyle. She is a Visiting Clinical Professor in Public Health Sciences and was the founding director of the first Integrative Medicine program at the UC Davis School of Medicine. She completed her postgraduate studies in Brazil and did her postdoctoral training in immunogenetics and functional genomics at the University of Illinois at Urbana-Champaign.