Antioxidants: The Importance of Eating your Rainbow
You may have heard of the idea of putting a rainbow on your plate every day. This is based on the knowledge that a wide variety of colourful plant-based foods will contain a whole range of beneficial antioxidants.
In this blog we’ll take a look at antioxidants and why they’re so valuable to our health.
What are Antioxidants?
Antioxidants are plant chemicals, often referred to as phytochemicals. These substances naturally occur in plants and are known to provide a whole range of health benefits.
Antioxidants and Free Radical Damage
Antioxidants are able to prevent our body cells being damaged by oxidation. This is a process connected with our natural metabolism which creates unstable molecules known as free radicals.
Free radicals are oxygen molecules which have split into single atoms with unpaired electrons. Because electrons prefer to be in pairs, these lone electrons are unstable. They seek out other electrons so they can become stable, causing oxidative stress in the process. It’s a chain reaction which will carry on unabated unless the free radical can be neutralised.
A simple example of oxidation is a cut apple turning brown when exposed to the air.
The body has developed strategies to quench this process before it can damage cells. This is where antioxidants come in. They possess an extra electron which they can donate to arrest the process of oxidation.
Free Radical Damage
Free radicals are believed to be behind degenerative process in the body including ageing, DNA damage, chronic disease and inflammation.
Many substances are also able to produce free radicals, including food, environmental chemicals like air pollution or tobacco smoke, burnt or charred foods, intense exercise, chronic stress, chemical-based household and beauty products and even sunlight.
Many antioxidants function as plant pigments, where their role is to provide protection for the plant from its own free radicals, microbes, ultraviolet light and to prevent it being eaten insect pests.
Looking at the colour of a fruit or vegetable gives us a clue that it contains a certain level of antioxidants, even if its colour does not always tell us exactly what kind of antioxidant it contains. Most plant foods contain many different antioxidants.
Types of Antioxidants
Although there are many kinds of antioxidants, two common classifications include:
This antioxidant family includes flavonoids, of which over four thousand are known to be in existence. Examples of flavonoids include quercetin, rich in red onions, and rutin which is found in apples and citrus fruits. One specific type of flavonoid is found in green tea.
Other examples include flavones, anthocyanins and catechins which are rich in berry fruits as well as isoflavones, which are found in legumes.
Anthocyanins tend to give foods a blue, purple or red colour. The darker the blue, the higher the anthocyanidin content. Betacyanin gives beetroot its wonderful purple colour.
One polyphenol which has been extensively researched is resveratrol, which is found in red wine and grape skins.
Examples of carotenoids include beta carotene, lutein and lycopene.
Lycopene is a reddish/pink colour and is rich in tomatoes, watermelon and pink grapefruit, whereas lutein is found in green leafy vegetables such as kale and yellow vegetables like squash. Good sources of beta carotene include carrots, sweet potatoes and green leafy vegetables. It has a red/orange pigment.
Certain vitamins and minerals can also act as antioxidants, namely vitamins A, C and E, zinc and selenium.
Curcumin, the orange pigment in turmeric, also acts as a powerful antioxidant.
Special Properties of Antioxidants
Certain antioxidants seem to protect certain tissues preferentially. Lutein for example has been found to support eye health, while anthocyanins appear to play a role in heart health.
Eating Your Rainbow
Even though it’s important to eat a good range of colours, it’s best not to get too hung up on which pigments have which function. Each colour is related to a whole range of health benefits with no one being superior. It’s all in the balance.
Current UK Government advice is to eat five portions of fruit and vegetables per day, but studies show ten or more portions per day offer significant protection against chronic disease.
Make vegetables the main part of your meal on the centre of your plate. Choose a variety of different colours both in your shopping trolley and with every meal. Aim to eat something red, green, orange/yellow, blue/purple and white every day.
Although we often hear we are what we eat, more accurately we are what we digest and absorb. This demonstrates the importance of ensuring your digestive system is in tip top health.