Decoding Antioxidants: Why Are They Good For You? Where Can You Get Them?

Medically reviewed by Dr. Karyn Shanks, MD Dr. Karyn Shanks Dr. Karyn ShanksMD facebook_iconinsta_icon
Written by , MSc (Biotechnology), Professional Certificate In Food, Nutrition & Health Swathi Handoo MSc (Biotechnology), Professional Certificate In Food, Nutrition & Health Experience: 4 years
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Right from your seven-year-old kid to your seventy-year-old father, one general instruction we all have received from our doctors is, “eat citrus fruits, beets, and greens.” I, for one, got sick of listening to this rant.

Why do you think people of all age groups are advised to consume these fruits and veggies? If ‘vitamins’ is your answer, well, you are partly right. But the bigger hero here would be antioxidants.

Fruits – especially dark berries greens, nuts – and the panoply of edible plants are natural reservoirs of antioxidants. These special foods protect you in powerful ways, so you can stay fit as a fiddle – at seven, seventeen, or seventy! How? You will know – keep scrolling down!

Table Of Contents

What Are Antioxidants?

Antioxidants are human-made or natural substances that may prevent or delay cell damage caused by oxidation (see below) Vegetables and fruits are excellent sources of antioxidants. Diets high in these elements enhance your immunity and promote longevity (1).

Some common antioxidants we all consume through our diets are vitamins C and E, β-carotene, lycopene, lutein, and zeaxanthin. These bioactive ingredients interact with harmful reactive chemical species called free radicals.

What do free radicals do to your body? How do these antioxidants eliminate them? And where can you get antioxidants abundantly? I’ve got the answers to all these questions. So, let’s start the quest!

First things first…

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How Do Antioxidants Work?

To understand this, you must know more about free radicals – which are constantly produced when the body produces energy. These free radicals are the price we pay for using oxygen to manufacture energy – resulting in high energy, potentially damaging byproducts we call free radicals. These include species known as superoxide ion, hydroxyl radical, hydrogen peroxide, alkoxy radical, hypochlorous acid, peroxynitrite, organic hydroperoxide, and peroxyl radical (2).

The names just flew above your head? Let me simplify them for you. Look at this diagram.

The blue spheres are electrons in a free radical molecule. The green spheres are electrons in an antioxidant molecule. It’s evident from the picture that free radicals have an unpaired or single electron in their outermost orbit (shell) – let’s call it a ‘loner’. This loner needs another unpaired electron or has to pair with another loner (unpaired electron) to become stable.

These loner electrons can interact with normal tissue and cause damage. This damage, referred to as “oxidative stress,” can lead to inflammation, changes in normal tissue structure and function, and cancers. But when these loner electrons interact with antioxidant molecules, they’re neutralized, mitigating the damage they can cause.

Free Radical Facts

  • Free radicals are naturally formed when you exercise and when your body converts food into energy.
  • Your body can also be exposed to free radicals from a variety of environmental sources, such as cigarette smoke, air pollution, and sunlight.
  • These loner electrons can interact with normal tissue and cause damage. This damage, referred to as “oxidative stress,” can lead to inflammation, changes in normal tissue structure and function, and cancers. But when these loner electrons interact with antioxidant molecules, they’re neutralized, mitigating the damage they can cause.
  • In excess, free radicals accelerate aging, trigger inflammation, and cause cancers.

 

So, what do antioxidants do? How do they work?

Antioxidants are designed to neutralize free radicals. Antioxidants are stable enough to donate an electron (another loner!) to a rampaging free radical, limiting the damage they can cause (1), (2).

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What Are The Different Types Of Antioxidants?

There are three primary types of antioxidants found in nature. These include phytochemicals, vitamins, and enzymes.

  • Phytochemicals

Phytochemicals are plant-based chemical derivatives – some of which are very powerful antioxidants. (They evolve to help plants adapt to exposure to ultraviolet light and other environmental toxins – when we ingest them, we get the benefit!)

Examples: Carotenoids, saponins, polyphenols, phenolic acids, flavonoids, etc.

  • Vitamins

Our body makes some of them while some come from natural sources like fruits, essential oils, microbes, and the sun!

Examples: Vitamins A, C, E, and D, coenzyme Q10, etc.

  • Enzymes

Enzymes are types of antioxidants that we manufacture within our bodies from the proteins and minerals we eat as part of our daily diets.

Examples: Superoxide dismutase (SOD), glutathione peroxidase, glutathione reductase, and catalases.

Now, let’s get to know the sources of these antioxidants.

What Are The Natural Sources Of Antioxidants?

The antioxidant potential of a food source (which could be a fruit, a veggie, a nut, or a beverage) is measured by an assay called the Oxygen Radical Absorbance Capacity (ORAC).

Higher the ORAC value, stronger is the antioxidant potential of that particular food source (3).

For your convenience, I have clubbed various sources of antioxidants into 7 clusters along with their ORAC values.

Disclaimer: The U.S. Department of Agriculture (USDA) releases these numbers. But it has recently removed its ORAC database from its NDL website due to “mounting evidence that the values indicating anti-oxidant capacity have no relevance to the effects of specific bioactive compounds.” Though the ORAC values speak volumes about the antioxidant capacity of a food, they shouldn’t be the only indicator to judge the goodness of that food. Please look at other parameters like metabolism, bio-availability, and risks assocaited with such rich foods before zeroing down on one.

So, here we go!

1. Vegetables

VegetableORAC value (µmol TE/100g)
Artichokes, raw6552
Asparagus, raw2252
Beets, raw1776
Broccoli, raw1510
Cabbage, red, raw2496
Carrots, raw697
Cauliflower, raw870
Chives, raw2094
Cilantro, leaves, raw5141
Cucumber, peeled, raw140
Eggplant, raw932
Garlic, raw5708
Ginger root, raw14840
Lettuce, romaine1017
Onions, raw913
Parsley, raw1301
Peppers, green, raw935
Potatoes, white, raw (with skin)1058
Pumpkin, raw483
Radishes, raw1750
Spinach, raw1513
Sweet potato, raw902
Tomatoes, red, ripe387

2. Fruits

FruitORAC value (µmol TE/100g)
Acai102700
Apples, raw (with skin)3049
Apricots, raw1110
Banana, raw795
Blackberries, raw5905
Blueberries, wild, raw9621
Cherries, raw3747
Cranberries, raw9090
Currants, black, raw7957
Dates, deglet noor3895
Elderberries, raw14697
Figs, raw3383
Goji berries3290
Grapefruit, pink, raw1640
Guava, white-fleshed2550
Kiwifruit862
Lemons, raw, (without peel)1346
Lime juice, raw823
Mango, raw1300
Oranges, raw1819
Papayas, raw300
Peaches, raw1922
Pineapple, raw385
Plum, black diamond, raw (with peel)6100
Prunes, uncooked8059
Pomegranates, raw4479
Raisins, golden, seedless10450
Raspberries, black19220
Rosehip96150
Strawberries, raw4302
Tangerines, raw1627
Watermelon, raw142

3. Spices And Herbs

Spice/HerbtORAC value (µmol TE/100g)
Basil, fresh4805
Basil, dried61063
Dill, fresh4392
Marjoram, fresh27297
Oregano, dried175295
Peppermint, fresh13978
Sage, fresh32004
Cardamom2764
Chilli powder23636
Cinnamon, ground131420
Cloves, ground290283
Cumin seed50372
Nutmeg, ground69640
Pepper, black34053
Rosemary, dried165280
Thyme, dried157380
Turmeric, ground127068
Tarragon, fresh27426

4. Nuts And Seeds

Nuts/SeedsORAC value (µmol TE/100g)
Almonds4454
Brazil nuts, unblanched, dried1419
Cashew nuts, raw1948
Hazelnuts9645
Macadamia nuts, dry roasted1695
Pecans17940
Pine nuts, dried720
Pistachio nuts, raw7675
Walnuts13541

5. Cereal Grains And Beans

CerealORAC value (µmol TE/100g)
Rice bran24287
Sorghum, bran100800
Sorghum grain, red14000
Sumac bran, raw312400
Sumac grain, raw86800
Oat bran2183
Oatmeal, toasted2175
Lentils, raw7282
Soybeans, mature5409
Peanuts3166
Pinto beans, raw8033
Kidney beans, raw8606
Black beans, raw8494

6. Beverages

BeverageORAC value (µmol TE/100g)
Red wine3607
White wine392
Chocolate syrup6330
Black tea313
Green tea1253
Coffee~2500
Beer~80

7. Miscellaneous Products

ProductORAC value (µmol TE/100g)
Dark chocolate20816
Milk chocolate7519
Cocoa, unsweetened powder55653
Bread, multi-grain1421
Peanut butter, smooth3432
Olive oil, extra virgin372
Peanut oil106
Fish and seafood30-6500
Meat and meat products0-850
Poultry and poultry products50-1000
Snacks and biscuits0-1170

(3), (4)

Phew!

By now, you should know what foods to eat and why! Like I said, we already consume a fair fraction of antioxidant-rich foods. The only change needed is to have these foods unprocessed and raw. Wherever possible, replace frying with boiling and sautéing. This prevents the disintegration of antioxidants.

Let’s assume that you took pains to switch from fried to boiled and blanched foods. What changes should you look out for? What will the antioxidants in these foods do to your body? Continue reading to find out.

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Benefits Of Taking Antioxidants

1. Skin: Anti-aging, Skin Lightening, And Protective Effects

Skin Anti-aging, Skin Lightening, And Protective Effects
Image: Shutterstock

Like other organs, the skin too continuously produces free radicals like peroxides, superoxides, and singlet oxygen. This happens because of its metabolic activities and exposure to UV rays and visible light.

These free radicals need to be eliminated from your body. Due to accumulation, these highly reactive species trigger cellular damage, accelerate aging, cause cancer (melanomas), inflammation, pigmentation, and acne.

Your body produces enzymes to fight such oxidative stress. But by supplementing antioxidants through diet, you can achieve younger, glowing, and clear skin (5).

2. Liver: Anti-inflammatory, Anticancer, Hepatoprotective Effects

When liver diseases involve oxidative stress, antioxidants are the best medicine. Diseases like cirrhosis, jaundice, hepatocellular carcinoma (cancer), and parasitic infections are aggravated by free radicals.

Antioxidants like curcumin, resveratrol, caffeine, quercetin, naringenin, and silymarin can be effective in this regard.

Also, to combat this oxidative stress, your body produces antioxidant enzymes like superoxide dismutase, catalase, and glutathione reductase (6).

3. Heart: Cardioprotective And Hypolipidemic Effects

After the age of 50, 52% of men and 39% of women in the US experience major cardiovascular diseases (CVDs), viz. coronary artery disease, atherosclerosis, cardiomyopathies, cardiac hypertrophy, angina, and myocardial infarction.

Excessive oxidative stress generates reactive oxygen species (ROS) in your body, which can cause CVDs. In such cases, what is the best way to stay safe?

Yes, you are right! Antioxidant vitamins C and E and phytochemicals like quercetin, beta-carotene, lycopene, and lutein have shown excellent cardioprotective effects.

They scavenge the free radicals and trigger the production of antioxidants in your body (7), (8).

4. Brain: Antitumor, Antidepressant, Cognition-Promoting Effects

Brain Antitumor, Antidepressant, Cognition-Promoting Effects
Image: Shutterstock

Apart from mutations, high levels of free radicals in the blood increase the incidence and malignancy of brain tumors.

Supplementing your diet with antioxidants has a direct impact on the brain, cognition, learning, and memory.

Higher dietary intake of vitamins E and C during pregnancy helps in protecting the infants from brain tumors and deformities. Antioxidants also inhibit the pro-cancer activities that go on in your body – and can hence prevent tumors altogether (9).

5. Fertility: Therapeutic And Stimulating Effects

Fertility Therapeutic And Stimulating Effects
Image: Shutterstock

An elevated level of free radicals affects various systems in your body. And, believe it or not, fertility is one among them.

Reactive oxygen species (ROS) can have an impact on the sperm count, motility of the sperms, and the maturity or viability of the sperm. In females, poor egg quality, fallopian tube defects, endometriosis, and even ovulatory disorders can arise partly due to ROS in the blood.

Applying antioxidant therapy (vitamins and phytochemicals) to such infertility issues can restore the hormonal balance, scavenge free radicals, and improve spermatogenesis, oogenesis, ovulation pattern, and boost chances of conception (10).

Did You Know?

  • Diseases like arthritis, irritable bowel syndrome, asthma, Crohn’s disease, GERD, psoriasis, and periodontitis arise due to inflammation.
  • Free radicals are one of the reasons behind these disorders.
  • Consuming antioxidant-rich foods like green leafies, asparagus, broccoli, dark berries, citrus fruits, and nuts will help manage the inflammation involved in these disorders effectively.

 

With all these benefits, it is difficult to ignore antioxidants, isn’t it?

Think about the number of antioxidant-rich dishes you can whip up using the foods listed above – endless lists of recipes pop up in my mind already!

And for those of you that feel your diet alone is not enough for getting adequate antioxidants, we have something for you. Read on!

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How About Antioxidant Supplements?

1. Do They Work?

Not sure, because there is not enough research evidence to conclude. Some cite side effects while others the benefits. Most of the negative studies look at the effects of a single antioxidant on outcomes of a single (usually end-stage) disorder. Most experts in the nutritional medicine field agree this is not an appropriate way to test the effects of these nutrients.

2. Are They Available In The Market?

While most nutrition experts agree that food is the best way to obtain powerful antioxidants in your diet, there are good quality supplements available on the market. These can be used when deficiencies are determined or if there is an increased need due to illness or health challenges.

3. Will There Be Side Effects?

Taking supplemental antioxidants is generally quite safe, though a few problems are possible. The excessive vitamin-B complex would cause nerve damage due to excessive vitamin B6 ingestion. An overdose of vitamin C can cause nausea, diarrhea, orheadache. Though vitamins B and C are water-soluble and toxicity is quite rare, do take care. And some antioxidant supplements might interact with medications you’d be taking. So, check with your health care provider first.

Finally…

Nature has given us the most potent weapon to fight the deadliest of disorders – in the form of antioxidants.

Our diet should essentially consist of raw or minimally processed fruits and veggies, and cooked meats in regulated portions. On the contrary, the “standard American diet” provides overprocessed, fried, and greasy food with barely any antioxidants left.

It’s time you switch to healthy eating. And by now, you’d know that food is the simplest, cheapest, and sustainable source of obtaining potent antioxidants.

What’s even better is that there are not many documented side effects of taking these chemical scavengers orally. Safe bet!

So, pick up the ingredients of your choice, create and cook some quick recipes, and write your stories to us. We’d also be happy to address your comments, suggestions, and feedback – put them in the box below.

Happy detoxing!

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References

1. “Antioxidants: In Depth” National Center for Complementary and Integrative Health, U.S Department of Health and Human Services
2. “Free radicals, antioxidants and functional foods…” Pharmacognosy Review, US National Library of Medicine
3. “USDA Database for the Oxygen Radical…” Nutrient Data Laboratory, U.S Department of Agriculture (USDA)
4. “The total antioxidant content of more than…” Nutrition Journal, US National Library of Medicine
5. “Antioxidants in dermatology” Anais Brasileiros De Dermatologia, US National Library of Medicine
6. “Antioxidants in liver health” World Journal of Gastrointestinal Pharmacology and Therapeutics
7. “Role of Antioxidants for the Treatment…” Current Pharmaceutical Design, US National Library of Medicine
8. “Antioxidants and Cardiovascular Risk Factors” Diseases, US National Library of Medicine
9. “Can dietary antioxidants reduce the…” Current Drug Metabolism, US National Library of Medicine
10. “Antioxidants for female subfertility” The Cochrane database of systematic reviews
11. “Male Infertility: The Effect of Natural…” Diseases, US National Library of Medicine

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Dr. Karyn Shanks is a physician who lives and practices in Iowa City. Her work is inspired by the revolutionary science of Functional Medicine, body-mind principles, and wisdom gleaned from the transformational journeys of thousands of clients over her 25-year career.

Read full bio of Dr. Karyn Shanks
Swathi Handoo
Swathi HandooHealth & Wellness Writer
Swathi holds a master’s degree in biotechnology from Osmania University and has worked in places where actual science and research happen. She has four years of experience and a Professional Certificate in Food, Nutrition & Research from Wageningen University.

Read full bio of Swathi Handoo
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