Role of Antioxidants and Free Radicals in Our Body-20 Best Foods to Obtain Antioxidants.

Everything You Need to Know About Antioxidants and Free Radicals.

You might have come across the terms ‘antioxidants’ and ‘free radical’ during a discussion with your friends or family. But what are they? How do they interact, and what it has to do with your health?


Free radicals are highly reactive chemicals (oxygen-containing molecules with an uneven number of electrons) that can’t harm your body if they become abundant. When cells use oxygen to generate energy, free radicals are produced when a molecule gains or loses an electron in our body due to mitochondrial ATP (adenosine triphosphate) generation. This free radical starts looking for other molecules to snag an electron from. It creates a chain of molecules looking for other molecules to stabilize. It’s a natural process that helps stabilize the virus and bacteria in the body to combat infections. Our body can also be exposed to free radicals from various environmental sources, such as cigarette smoke, air pollution, and sunlight.

But when the ratio of free radicals becomes higher, it becomes a threat to the components that make up cells.

They have been associated with various diseases, including diabetes, heart disease, and cancer, and a lot of research has proven their relation with associated conditions.

The antioxidants are the molecules that block the activity and neutralize the free radicals, stopping them from causing damage. The primary function of antioxidants is to neutralize free radicals by giving up some of their electrons. By making this sacrifice, they operate as a natural “off” switch for free radicals. This helps break a chain reaction that can harm other molecules in the cell and cells across the body.


Our body needs to maintain a certain balance of free radicals and antioxidants. When free radicals outnumber antioxidants, it can lead to a state called oxidative stress. While oxidation is an ordinary and necessary process, too much of it can be hazardous. Prolonged oxidative stress can harm your DNA. This damage to your DNA raises your risk of cancer, and some experts believe it also plays a part in the aging process. It can even cause cell death in some cases.

Sources of oxidative stress can be external or internal such as;

Natural cause External cause
Metabolic functions Cigarettes
Exercise Pollution
Inflammation Certain drugs
Illness or infection Radiation
Stress Industrial chemicals
Shock Ozone

However, it is essential to comprehend that “antioxidant” refers to a chemical characteristic rather than a specific nutritional property. Because free radicals are so widespread, an appropriate amount of antioxidants is required to disarm them. No single antioxidant can neutralize all free radicals. Like free radicals, antioxidants behave differently depending on their chemical features.


The antioxidant content is measured using the ORAC (Oxygen Radical Absorbance Capacity) scale. It is a system created by researchers at the National Institute of Health (NIH) to assess the antioxidant capacity of various foods. ORAC is the most effective approach to determine how much a particular diet will aid your body in fighting free radicals.

There is no “official” daily recommended consumption of ORAC units. Various publications have suggested, and

optimal intake of 3,000-5,000 ORAC units per day,

while the USDA proposed 5,000 ORAC units per day. The United States government and health organizations recommend eating a diversified diet that includes at least 5 servings of fruits and vegetables each day and 6 to 11 portions of grains per day, with at least half of these servings being whole grains. On the other hand, the United Kingdom Food Standards Agency (UK FSA) and the Food and Drug Administration (FDA) recommend 5 servings of fruits and vegetables equivalent to 3,500 0RAC units.



Your body produces some antioxidants. Natural antioxidants produced by your body’s cells include alpha-lipoic acid and glutathione. The best way to get other antioxidants is through certain foods and vitamins.

Other vitamins and minerals-based are well researched and essential for the body are mentioned down below,

Vitamin A.

Sources include liver, cod liver oil, carrots, broccoli, sweet potatoes, butter, kale, spinach, pumpkins, collard greens, cheeses, eggs, apricots, cantaloupe melon, and milk. Provitamin A carotenoids such as beta-carotene, alpha-carotene, and beta-cryptoxanthin are precursors of vitamin A and have antioxidant properties. It is essential for eye health.

Vitamin C.

The best sources of vitamin C are oranges, limes and lemons, strawberries, papaya, red bell pepper, grapefruit, kiwi, potatoes, and herbs like parsley and thyme.  This antioxidant is found in many plant-based foods and helps restore other antioxidants like vitamin E that free radicals have damaged. Vitamin C may help protect against certain malignancies and heart problems, according to research.

Vitamin E.

Found in wheat germ oil, sunflower seeds, almonds, sunflower seeds, hazelnuts, mangoes, and avocados.  It plays a critical role in protecting cell membranes against oxidative damage. In 2017, a trial indicated that giving late-stage knee osteoarthritis patients 400 IU vitamin E once a day for two months improved clinical symptoms and reduced oxidative stress.


This compound can be found in tomatoes and tomato products, pink grapefruit, watermelon, and red peppers. It aids in the promotion of prostate and cardiovascular health. It also helps to reduce the proliferation of cancerous cells inside the breast, prostate, and kidney. A 10-year study connected this nutrient-rich diet to a 17–26% decreased risk of heart disease. A 2016 study linked high lycopene levels to a 31% reduced risk of stroke. Lycopene’s antioxidant properties appear to help persons with low blood antioxidant levels or excessive oxidative stress.


Polyphenols are naturally occurring antioxidants found in plant foods such as fruits, vegetables, black chokeberries, herbs, spices, tea, dark chocolate, and wine. They can work as antioxidants by reducing the risk of cancer, diabetes, and heart disease. They may also help reduce inflammation, which is linked to many chronic conditions. They benefit digestion by boosting good gut flora development and inhibiting bad. Some researches prove that cocoa flavanols increase blood flow to the brain and that these polyphenols boost working memory and attention.


It is found in grapes, dark chocolate, berries, and peanuts. This element is found in abundant grape and berry skins and seeds. They have been demonstrated to improve heart and lung health, prevent certain types of cancer (breast, colon, gastric, skin, and prostate), and lower general inflammation.

Lutein and Zeaxanthin.

They are structurally similar compounds. Some foods with high levels of these antioxidants include spinach and collard greens. Lutein and zeaxanthin also work to protect your eyes from free radical damage. Also, they play a huge role in managing the eyes’ age-related conditions, including AMD, cataracts, retinopathy, and uveitis. Apart from this, it had been reported by several pieces of research for the effect of these antioxidants on skin and sunburns.


Selenium is most often found in whole grains and animal products such as fish and eggs. The amount of selenium in grains and grain-based foods depends on the soil content where they grew. According to research published in the International Journal of Endocrinology and Nature Reviews Endocrinology, having an adequate selenium level in the body may help prevent thyroid diseases. It’s also a potent antioxidant that may help prevent certain cancers.


More of a mineral antioxidant, found in oysters, crabs, lobsters, beef, cereals, and mushrooms.  It is essential for the activity of around 100 enzymes in the body. Zinc supplementation studies in the elderly have indicated a reduction in infections, oxidative stress, and the production of inflammatory cytokines. It protects the arteries and also strengthens the immune system. 

This fact sheet highlights what the science says about antioxidants and health and proposes:

Antioxidant Benefits Source foods
  • Allium Sulfur compounds
  • Leeks
  • Onions
  • Garlic
  • Anthocyanin
Anthocyanins have been found to reduce blood pressure, improve vision, prevent tumour development, reduce the risk of cardiovascular disease, and modulate cognitive and motor function. They are also anti-inflammatory and antimicrobial.
  • Eggplant,
  • Grapes
  • Berries
  • Beta carotene
  • Pumpkin,
  • Mangoes,
  • Apricots
  • Carrots
  • Spinach
  • Parsley
  • Asparagus
  • Beets
  • Cantaloupe
  • Sweet potato
  • Tangerines
  • Tomatoes
  • Watermelon
  • Catechins


  • Red wine
  • Green tea
  • Black tea
  • Copper
  • Seafood,
  • Lean meat,
  • Milk
  • Nuts
  • Whole wheat
  • Sunflower seeds
  • Flavonoids
  • Tea,
  • Green tea,
  • Citrus fruits,
  • Red wine
  • Onion
  • Apples
  • Isolflavanols
  • Soybeans,
  • Tofu,
  • Lentils,
  • Peas
  • Milk
  • Cloves
  • Indoles
  • Cruciferous vegetables such as broccoli, cabbage, and cauliflower.
  • Ligans
It lowers risk of heart disease, menopausal symptoms, osteoporosis and breast cancer.
  • Sesame seeds
  • Bran
  • Whole grains
  • Vegetables
  • Lutein and Xanthin
Protects against eye damage and AMD.

Heals sunburns and Uv damage.

  •  Green, leafy vegetables like spinach
  • Corn
  • Lycopene
  • Tomatoes
  • Pink grapefruit
  • Watermelon
  • Manganese
Imprtant for brain and nerve function. Regulates blood sugar. Improves bone health specially osteoporosis.
  • Seafood
  • Lean meat
  • Milk
  • Nuts
  • Polyphenols
  • Thyme
  • Oregano
  • Wine
  • Black chokeberries
  • Fruits and vegetables.
  • Many spices
  • Resveratrol
  • Dark choclates
  • Berries
  • Peanuts
  • Grapes
  • Peanuts
  • Selenium
  • Seafood
  • Lean meat
  • Whole grains
  • Eggs
  • Vitamin A.
  •  Liver
  • Sweet potatoes
  • Carrots
  • Milk
  • Egg yolks
  • Canteloupe
  • Cheese
  • Butter
  • Kale
  • Vitamin C
  • Oranges
  • Blackcurrants
  • Kiwifruit
  • Mangoes
  • Broccoli
  • Spinach
  • Capsicum
  • Strawberries
  • Lime and lemons,
  • Strawberries
  • Papaya red bell pepper
  • Potatoes
  • Parsley and thyme
  • Vitamin E
  • Vegetable oils (such as wheatgerm oil)
  • Avocados
  • Nuts
  • Seeds
  • Whole grains
  • Zinc
  • Seafood
  • Lean meat
  • Milk
  • Nuts
  • Mushrooms
  • Coral reefs
  • Zoochemical
  • Red meat
  • Fish
  • Also derived from the plants that animals eat


Each antioxidant performs a distinct function and cannot be substituted for another. This is why it is important to eat a diverse diet.

How can you manage to eat the proper diet? Some tips here.


an image of nuts as antioxidants

Research done created a complete food database that includes the overall antioxidant content of common foods. As a result, the current antioxidant database is essential for further explaining the possible health impacts of phytochemical antioxidants in the diet.

Nutrients can be obtained from diet rather than supplements. Only 5% of us eat the recommended daily quantity of fruit and vegetables.

  Food Antioxidants Present FRAP Amount per 100gms ORAC Score/100 gms
1.  Cinnamon (consume as a spice and do not exceed 1 teaspoon per day for an adult due to the content of coumarin) polyphenols 139.9mmol 267,536 (µmol TE)
2.  Oregano thymol, carvacrol, limonene, terpinene, ocimene, caryophyllene 72.8mmol 175,295 dried (µmol TE)13,970 fresh
3.  Basil lutein, zeaxanthin, beta-carotene, beta-cryptoxanthin 28.1mmol 61,063 dried (µmol TE)      4,805 fresh
4.  Pecans  zinc, tocopherols  10.06mmol 17,940 (µmol TE) 
5.  Walnuts  ellagic acid, ellagitannins, catechin, melatonin  20mmol  13,541 (µmol TE) 
6. Dark Chocolate polyphenols, flavonols, catechins. 15mmol  13,120 (µmol TE)
7.  Spinach  lutein & zeaxanthin, 0.9mmol 10,513 (µmol TE) 
8.  Prunes  neochlorogenic acid, chlorogenic acid 1mmol 8,059 (µmol TE)
9.  Artichoke chlorogenic acid, Vit A, C & K 4.7mmol 6,552 (µmol TE)
10.  Raspberries vitamin C, quercetin, ellagic acid 4mmol 5, 069 (µmol TE)
11.  Blueberries  anthocyanins zeaxanthin 9.2mmol 4,669 (µmol TE)
12.  Pomegranates flavonoids, anthocyanins, punicic acid, ellagitannins 9mmol 4,479 (µmol TE)
13.  Strawberries anthocyanins, ellagic acid, quercetin, kaempferol 5.4mmol 4,302 (µmol TE)
14.  Goji berries zeaxanthin 4.3mmol 4,130 dried (µmol TE), 3,290 fresh
15.  Coffee chlorogenic, ferulic, caffeic, and n-coumaric acids 2.5mmol 2,780 (µmol TE)
16.  Red Cabbage vitamins, xanthine, lutein 2.2mmol 2,498 raw, 3145 boiled (µmol TE)
17. Beets rutin, epicatechin and caffeic acid 1.7mmol 1,776 (µmol TE)
18.  Kale beta-carotene, Vit C, flavonoids, queretin, kaempferol, polyphenols. 2.7mmol 1,770 (µmol TE)
19.  Broccoli glucoraphanin, lutein & zeaxanthin, 0.5mmol 1,590 (µmol TE)
20.    Pinto Beans polyphenols, flavonoids, kaempferol 2.0mmol Boiled 904 (µmol TE)

To learn about the research-based effects of these above high anti-oxidants foods? Read it here.

The USDA tested over 100 foods from all categories and developed an authoritative list of the top 20.

antioxidants supplements


Foods are indeed the best source of antioxidants for the diet, and there are no concerns about the safety of antioxidants received from food sources. Antioxidant supplements contain concentrated forms of antioxidants, which are chemicals that stabilize free radicals. They are usually thought to be healthful, but when taken in excess, they can be harmful. Supplementation needs to be well considered as it can adversely affect your health depending on your state and what supplements you take. Read this article to view the related concerns.  

There is no harm in taking antioxidants supplements. However, it is usually more beneficial to get your antioxidants from direct sources like food. Taking antioxidant supplements in large doses is not recommended for many reasons.

Some of the harmful and sound effects are mentioned here.



  • According to many research papers, (1) (2) (3), antioxidant supplements, particularly vitamins C and E, have been found to interfere with how your body adjusts to exercise and even diminish some of the health benefits associated with exercise.




The National Center for Complementary and Integrative Health (NCCIH) fact sheet has more information on the safety of dietary supplements.

It is essential to consult a doctor before any supplementation as well.

To prime with time, consume a healthy, balanced diet without worrying about taking antioxidant supplements. It is vital to seek out natural sources of antioxidants in the form of a healthful diet.

Suppose You Are Considering Antioxidant Supplements. Remember that antioxidant supplements should not be used in place of a healthy diet or conventional medical care or to avoid seeing a health care practitioner about a medical concern.

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Being a Doctor by profession, Aimen is passionate about helping people get better health in their lives. Aimen enjoys her research on Prime With Time subjects and strives to create better awareness of the problems and changes related to women's health.

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