Why It’s Worth Adding Antioxidant-Rich Foods To Your Diet

The term “antioxidants” is everywhere these days. It’s linked to superfoods, skincare, dark chocolate, and even red wine. Antioxidants are marketed to combat chronic disease, reverse aging, and boost overall wellbeing – but what exactly are antioxidants, where can you find them, and how are they beneficial to your health?

Let us explain.

What is an antioxidant?

“Antioxidant” is not so much the name of a substance or compound, but a description for what a range of substances can do – neutralize free radicals and help protect cells from damage. (1) All antioxidants have the ability to act as stable electron donors.

Antioxidants are molecules that make their way into cells to protect the body from unstable free radicals.

Glasses of water infused with pomegranate

Infusing water with different fruits such as lemon and pomegranate seeds is a simple (& sweet!) way to get an extra boost of antioxidants into your diet.

Let’s quickly talk antioxidants, avocados, and lemon juice

Before we get to antioxidants in the body, let’s tackle browning avocados first. Some fruits and vegetables (like avocados) contain compounds that, when exposed to oxygen, will turn a brown-black color.

Do you know the trick to keep your avocado or guacamole from browning while it’s sitting out in the open or left in the fridge overnight?

The answer is lemon juice!

A bowl of guacamole surrounded by avocado and lemon

It’s lemon juice! Just squeezing a small amount of a strong antioxidant like lemon juice can keep your guac from browning for at least a day – giving you the perfect base for avocado toast in the morning!

Since oxidation is the catalyst for the reaction, it makes sense that introducing an anti-oxidation agent would prevent browning.

Antioxidants, like lemon, neutralize free radicals in the body

Just as oxygen in the air causes a sliced avocado left on the counter to brown, oxygen in the body (along with other oxidizing agents) rips off electrons from molecules, which renders them defective. These defective atoms that are missing an electron are known as free radicals. Free radicals are a form of waste constantly being produced by cells. They are largely a byproduct of your metabolism running. (Think of free radicals as the brown mush on your perfectly good avocado)

At a molecular level, antioxidants inhibit oxidation without creating collateral damage. This means antioxidant molecules donate electrons to free radicals and neutralize them without compromising their own stability. (Like lemon juice on guac)

Oxidative stress is linked to chronic illness

When free radicals accumulate and go unchecked, they often cause a cascade of reactions which throw your body into a state known as oxidative stress. Oxidative stress hikes up your risk of heart disease, cancer, arthritis, strokes, Parkinson’s disease, emphysema, respiratory diseases, immune deficiencies, bad acne breakouts, and other conditions. The good news is, we are not defenseless against free radicals.

Consuming antioxidants along with antioxidants produced by your body can lower spiked free radical levels. (2)

Although free radicals are produced in the body, lifestyle and environmental factors can accelerate their production. Pesticides, tobacco, alcohol, poorly-managed stress, air pollution, lack of sleep, UV rays, radiation, certain prescription medications, and substances found in fried foods expedite free radical reactions. (3)

Fortunately, eating a diet rich in exogenous antioxidants has been shown to help neutralize free radicals, reduce the risk of chronic disease, and boost overall health.

A woman's hands holding a bowl of colourful fruits and vegetables including avocado, blood oranges, pomegranate, clover leaves, and more over top of a cutting board.

You can increase your intake of antioxidants by eating a more colorful variety of fruits, vegetables, nuts, seeds, and legumes.

Did you know?
The body makes its own antioxidants, called endogenous antioxidants. Antioxidants from outside the body are known as exogenous.

Different types of dietary antioxidants

Antioxidants found in food can be put in two general groups: water-soluble and fat-soluble antioxidants. Fat-soluble antioxidants perform their actions in cell membranes, while water-soluble antioxidants act primarily in the fluid inside and outside of cells.

Did you know?
A common misconception is that all antioxidants are interchangeable. They are not! Each antioxidant has unique biological properties and chemical behaviors.

Vitamins A, C, and E, and the minerals copper, zinc and selenium are vitamins and minerals with antioxidant effects. Other dietary food compounds — known as the non-nutrient antioxidants such as lycopene, which is a phytochemical found in tomatoes — have an even greater antioxidative effect. (4)(5)

Your body produces some endogenous antioxidants, but you can also find them in lots of familiar foods, vitamins, and minerals. Some exogenous antioxidant sources include:

  • Vitamin C (oranges)
  • Vitamin A (sweet potatoes, carrots)
  • Vitamin E (avocados)
  • Selenium (whole grains)
  • Lutein (spinach, corn)
  • Beta-carotene (pumpkin, carrots, mangos)
  • Lycopene (tomato)
  • Lignans (sesame seeds)
  • Flavonoids (tea, red wine, onions) (6)
  • Polyphenols (oregano, thyme)
  • Indoles (kale, broccoli, cabbage)

Different antioxidants are beneficial for different bodily functions beyond free radicals, which is why it’s so important to have a variety in what you eat.

On top of that, different antioxidants have been shown to have a diverse range of health benefits. For example, Lutein, which is found in spinach, has been linked to a lower incidence of eye lens degeneration and associated blindness in the elderly. (7)

Man wearing a chef apron slicing a tomato on a cutting board for his salad

Men who eat plenty of the antioxidant lycopene (which is found in tomatoes) may be less likely to develop prostate cancer. (8)

Did you know?
Flavonoids, such as the tea catechins found in green tea, are believed to contribute to the low rates of heart disease in Japan. (9)

Measuring and testing antioxidant levels

There are several tests that scientists use to measure the antioxidant power of foods and dietary supplements.

ORAC, which stands for oxygen radical absorbance capacity, is a test that measures the ability of a food or supplement to neutralize oxygen-free radicals in a test tube. The higher the score – the higher the antioxidant power. You can browse foods alphabetically or search by keyword in an ORAC database. (10)

Did you know?
The USDA pulled its ORAC database off their public website, citing two main reasons: It was routinely misused by advertisers, and more human clinical trials are needed around health claims. (11)

Generally speaking, ORAC scores are a useful guideline when referring to whole foods.

Another antioxidant test is the FRAP analysis, which stands for the ferric reducing ability of plasma. This test measures the antioxidant content of foods by how well they can neutralize a specific free radical. (12)

According to the USDA, the ORAC, FRAP, and other measures for antioxidant capacity all generate distinct values that cannot be compared that well directly. This can make antioxidant ratings confusing. (13)

Blueberries are one of the best natural sources for antioxidants and superfoods. Testing has shown they are packed with anthocyanins and other antioxidants.

Did you know?
A study focusing on people with a high risk of developing Age-related Macular Degeneration, a leading cause of vision loss, found risk was lowered by 25% when treated with a high-dose combination of vitamin C, vitamin E, beta-carotene, and zinc. (14)

A list of high-antioxidant foods

There is a huge variety of healthy foods to choose from that are high in antioxidants. Which are the best? The USDA tested over 100 foods common in the western diet and developed an authoritative list of the top 21. (15)(16)

21 foods highest in antioxidants

1. Small red beans
2. Wild blueberries
3. Red kidney beans
4. Pinto beans
5. Cultivated blueberries
6. Cranberries
7. Artichokes
8. Blackberries
9. Prunes
10. Raspberries
11. Strawberries
12. Red delicious apples
13. Granny Smith apples
14. Pecans
15. Sweet cherries
16. Black plums
17. Russet potatoes
18. Black beans
19. Plums
20. Gala apples
21. Dark leafy greens

Did you know?
To reap the benefits of antioxidants, foods are best consumed raw, microwaved, or lightly steamed. It’s not a good idea to heavily bake, pressure cook, or boil them. (17)

Foods highest in antioxidants, arranged by food group

Interested in learning about more foods that are high in antioxidants?

A 2010 report published in the Nutritional Journal analyzed the antioxidant content of over 3100 foods, beverages, spices, herbs, and supplements also provides an excellent guide to antioxidant-rich foods by food group.

Overall, plant-based foods offer the most abundant source of antioxidants. (18)

Fruits: Acai berries, cranberries, red grapes, peaches, raspberries, strawberries, red currants, figs, cherries, pears, guava, oranges, apricots, mango, red grapes, cantaloupe, watermelon, papaya, and tomatoes.

Vegetables: Broccoli, spinach, carrots, and potatoes are all high in antioxidants, and so are artichokes, cabbage, asparagus, avocados, beetroot, radish, lettuce, sweet potatoes, squash, pumpkin, collard greens, and kale.

Spices: Cinnamon, oregano, turmeric, cumin, parsley, basil, curry powder, mustard seed, ginger, pepper, chili powder, paprika, garlic, coriander, onion, and cardamom.

Herbs: Sage, thyme, marjoram, tarragon, peppermint, oregano, savory, basil, Indian Winter cherry, and dill weed.

Cereals and nuts: Oatmeal, walnuts, hazelnuts, pistachio nuts, almonds, cashews, macadamia nuts, and even peanut butter.

Beverages: Espresso, red wine, pomegranate juice, apple juice, grape juice, prune juice, tomato juice, pink grapefruit juice, as well as green, black, and plain tea.

A study on blood orange juice found it had significantly higher antioxidant power than sugar water with the same amount of vitamin C. (22)

Did you know?
Adding milk to your coffee or tea can block antioxidants. (19)

What about antioxidant supplements?

Having a healthy amount of antioxidants is key to overall wellbeing, but keep in mind more is not always better. When it comes to antioxidant supplements, stick to low-dose and avoid overdoing it. An overload of antioxidants can be harmful.

You can get a low-dose supplementation of antioxidants from your daily multivitamin, but be wary of overdoing it with supplements. Studies have shown that taking high doses of antioxidant supplements can promote instead of preventing oxidative damage. In fact, some studies have even shown excessively high intake of antioxidant supplements increase the risk of death. (20)

Did you know?
Large doses of vitamin E – over 400 IUs daily – have been linked to a possible increase in overall mortality. But, this risk doesn’t apply to a typical multivitamin. (21)

Research has shown consuming a diet rich in lots of fruits and vegetables, along with other nutrient-dense foods is the most effective way to absorb antioxidants.

The bottom line – taste the (antioxidant) rainbow!

As a general rule of thumb, focus on eating more colorful vegetables and fruits. Research has shown the best strategy to ensure you are getting all the antioxidants you need to promote optimal health is consuming more natural nutrients found in whole foods.

Need some simple guidance on how to fill your plate? The USDA says to fill half of your plate up with colorful fruits and vegetables for every meal. No counting or measuring required! (23)

And remember, when it comes to adding antioxidants to your diet, no one food, food group, or antioxidant should be your sole focus. Try and incorporate a variety of plant-based nutrients into your diet.

We all respond to different antioxidants in different ways, so if you’re thinking of taking larger amounts of any antioxidant supplements, ask your doctor or dietician first.

Did you know?
People who are heavy smokers should be especially careful with antioxidant supplements. Research has linked long-term, high doses of beta-carotene supplementation to an increased risk of lung cancer. (24)

Interested in some of the health benefits associated with antioxidants and want to know more about specific antioxidants? Talk to a trusted healthcare provider about ideas to add-in more antioxidant-rich (& colorful!) foods to your diet.


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