You've probably heard the term "antioxidants", but do you know why you should eat them and how they can be incorporated into your diet?

Antioxidants are the reason why a diet rich in colourful fruit and vegetables, wholegrains, nuts and seeds is recommended. In fact, theyve been called the superheroes of nutrition. But why exactly is that?

Science lesson 101

To understand what antioxidants are, we first need to understand two key terms: reactive oxygen species (ROS), also called free radicals, and oxidative stress. ROS exist in humans to protect the body against harmful substances from the environment.

When our environment becomes unhealthy and toxins (like car emissions, anti-cancer drugs, pesticides, too much sun and cigarette smoking) bombard our bodies, ROS are formed in an effort to protect the body.

However, when too many ROS are formed, and they are not eliminated, they can damage our cells. ROS are chemically unstable and cause damage by stealing electrons from body cells to make them more stable.

Think of free radicals like a chair with three legs: unstable and unsteady, with the potential to cause damage to the DNA in our cells. This damage is called oxidative stress.

ROS can also bind to fats in the diet and form a harmful substance called lipid peroxidase. Scientists believe that oxidative stress may play a central role in various autoimmune diseases, heart disease, type 2 diabetes, cancer, arthritis, stroke, poor immunity, ageing, memory loss, poor vision, and even wrinkles.

How can our bodies fight free radicals?

The body has enzymes that normally scavenge the excess ROS. These are called super oxide dismutase, catalase and glutathione peroxidase. They rely on a large variety of vitamins, minerals and phytonutrients in the diet to function optimally.

Thus it appears that a diet high in fats and lacking in vitamins, minerals and phytonutrients contributes to the cell damage responsible for developing chronic lifestyle diseases.

The role of antioxidants

Enter the anti-oxidant: a powerful molecule that empowers the enzymes to neutralise the harmful ROS. There may be hundreds and possibly thousands of substances that can act as antioxidants, each serving a specific task in the body, which is why it is important to have a varied diet.

These include phenolic compounds like caffeic acid (in coffee) and ellagic acid (in green tea); flavonoids like quercetin (e.g. apples, cranberries, onions, lettuce, broccoli, tomato, olive oil); catechins (tea); flavones (celery, parsley) and anthocyanidins (cherries, raspberries, strawberries and grapes), resveratrol (red grapes, red wine), lignans (barley, pomegranate, flaxseeds); tannins (legumes, leafy green vegetables); phytoestrogens (soy); andlutein and zeaxanthin (eggs).

Eat the rainbow

Its easy to eat more antioxidants, just eat a more plant-based diet focusing on foods like fruit, vegetables, wholegrains, nuts and seeds. Focus on eating all the colours of the rainbow when choosing your daily fruit and vegetables with the help of this handy table:

Other foods containing various antioxidant compounds include coffee, green tea, rooibos tea, red wine (in controlled portions), red kidney beans, sweet potato, unprocessed wholegrains (e.g. oats, wholegrain bread, whole-wheat pasta, corn), and eggs.

Should I take antioxidant supplements?

As almost all health organisations globally recommend the consumption of a minimum of five portions of fresh fruit and vegetables daily, it seems a food first approach is the best practice to meet your antioxidant needs.

In fact, there isnt much evidence to support the notion that we get a higher intake of antioxidants in the form of supplements, with some studies showing no benefit, and some studies even reporting that excess antioxidant supplements may have a detrimental effect on our heath.

Simply increase your intake of fresh fruits and vegetables by experimenting with different tastes and textures and shopping for seasonal produce.

Image credit: iStock

Monique Piderit

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Why antioxidants are the superheroes of nutrition - Health24