Can antioxidants actually help you live longer?

A collection of different coloured fruits and vegetables

Here’s everything you need to know about antioxidants and how to add them to your diet.

What are antioxidants and free radicals?

To put it as simply as possible, antioxidants are molecules that protect your body from oxidative stress that’s caused by free radicals. Free radicals are the name given to unstable molecules formed naturally through processes like metabolism or from external factors such as pollution, smoking, high-fat diets and UV exposure. When free radicals accumulate, they can damage cells and DNA, contributing to ageing and diseases like cancer, heart disease and neurodegenerative conditions.

Antioxidants neutralise free radicals by giving them electrons, effectively stabilising them and preventing cellular damage. They act as the body's defence system, maintaining balance and protecting tissues from long-term harm.

“The easiest way to understand antioxidants is to imagine you are in a shopping centre, minding your own business, and a bunch of burglars come bursting in. Then, the security guards come to the rescue and calm everything down, peace is restored, and you can buy your shopping as planned,” explains registered nutritionist Michaella Mazzoni.

“In the body, this is the relationship which exists with oxidative stress and antioxidants. The burglars are the free radicals, which cause oxidative stress and damage to the body. The security guards who swoop in and save the day are the antioxidants, which essentially give themselves over to neutralise free radicals and prevent further oxidative stress.”

Antioxidants can be natural or manmade, and include vitamins A, C, and E, as well as beta-carotene, lycopene, lutein and selenium.

What foods can you find antioxidants in?

“The simplest way to think about antioxidants in the diet is to focus on a variety of very richly pigmented foods in nature,” explains Michaella. “Dark berries, dark leafy greens, purple cabbage, sweet potatoes. Generally speaking, the darker in colour a food is in nature, the higher it is in antioxidants.”

Vitamin C foods including citrus fruits, strawberries, bell peppers, kiwi, broccoli and spinach
Vitamin E foods including nuts, avocados and vegetable oils
Beta-carotene rich foods including carrots, sweet potatoes, apricots and other orange and yellow vegetables
Polyphenols found in berries, dark chocolate, green tea and coffee
Selenium found in brazil nuts, seafood, eggs and wholegrains
Flavonoid rich foods like apples, onions and black tea
Lycopene rich foods like tomatoes, watermelons, pink grapefruits and papayas

Why do some people think antioxidants help you live longer?

Many preach the benefits of antioxidants because of their protection against the nasty stuff, according to Michaella. “Free radicals and oxidative stress are associated with heart disease and cancer development. The belief that you will live longer by eating more antioxidants is due to the antioxidants protecting and preventing oxidative stress.”

The idea was first suggested back in 1955, when scientist Denham Harman wrote a paper proposing that there was a link between cellular degeneration and free radical reactions. It suggested that free radicals, naturally produced during cellular metabolism, cause damage to DNA, proteins and other cell components, contributing to ageing, mutations and diseases like cancer. However, later studies refuted this claim.

And while no single food or nutrient guarantees a longer life, there’s no denying that an antioxidant-rich diet containing a variety of fruit, vegetables, nuts and seeds can contribute to an overall healthy life, and a potential reduction in risk of chronic disease. For example, studies show that diets high in antioxidants, particularly flavonoids can support heart health by lowering blood pressure and improving blood vessel function. Other research has found that antioxidants like vitamin E and certain phytochemicals in leafy greens and berries are associated with better cognitive function, while some antioxidants, including beta-carotene and lycopene, may help prevent certain cancers by protecting cells from DNA damage and supporting the body’s natural defences.

Baked kale crisps with smoky paprika salt

Is there too much of a good thing when it comes to antioxidants?

Like all things, too much can do you more harm than good. And in the instance of antioxidants, over-consuming them, especially in supplement form, can have a negative impact on your body.

For example, while there’s no evidence to suggest that beta-carotene from food is harmful, beta-carotene supplements have been found to increase the risk of lung cancer in smokers, and those who have been exposed to asbestos at work.

“When it comes to supplements you need to be careful with antioxidants which are fat soluble (vitamin A, D, E and K) as they can build up in the body,” warns Michaella. “Vitamin K has a blood thinning effect, too, so be careful if you are on blood thinning medication or have any conditions associated with circulation. It is sometimes combined with vitamin D as well so be mindful of the dose.”

Michaella also warns about the over-consumption of Vitamin A and dangerous build-ups in the liver. “A sign of too much vitamin A can be palms and soles of feet becoming orange – you’ll find high amounts of it in orange foods like carrots and sweet potatoes,” she says. “If you are taking multiple supplements, be careful not to take too much vitamin A or any of the other fat-soluble vitamins as it is easy to accidentally take too much. I often see vitamin A in skin complexion products which, if you are also taking as a supplement, can quickly add up to too much.”

Antioxidant supplements can also be harmful to people who have underlying health conditions, are pregnant and undergoing chemotherapy, so always speak to your GP before making any decisions about supplements. And remember, most of us can get all the antioxidants we need from our diets alone, so maybe varying the amount of plants you eat a week really could be the key to living to 100.