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What Do Antioxidants Do for the Body?

Chin chin holds a BS degree in food technology. She enjoys sharing important information about health and food-related topics.

Image of berries with modification by Chin chin

Image of berries with modification by Chin chin

Many companies selling supplements and various products—including berries, green teas, and anti-aging creams—are taking advantage of the hype about the role of antioxidants in averting diseases or reversing the aging process.

Much of the information that is available out there promotes the good things that antioxidants can do to people's health. In addition to reviewing those claims, I will highlight the not-so-good side of antioxidant consumption. I will also give some recommendations to help you incorporate antioxidants into your diet in a healthy manner.

What Are Antioxidants?

Antioxidants are substances that fight against oxidants. Oxidants, also called free radicals, are by-products of the process called oxidation, which naturally occurs inside the human body during aerobic respiration, metabolic processes, and inflammation. Free radicals may also come from external sources as the body is exposed to pollution, smoking, sunlight, X-rays, alcohol, certain food, and stress.

Why Are Free Radicals Bad?

Free radicals are active, unstable atoms or molecules. They have unpaired electrons and so they scavenge the body to donate or grab electrons to and from other cells.

Free radicals cause damage to the body cells—they alter the code in a DNA strand, change the property of cell membranes and cause low-density lipoprotein (LDL) or bad cholesterol to deposit as plaque in heart vessels. We don’t see these changes happening at the cellular level, but later on these manifest as diseases: cancer, heart disease, vision loss, Alzheimer’s disease, kidney disease, etc.

Visible damage of free radicals can be seen on the skin in the form of wrinkles. Free radicals can harm the collagen present in the skin, changing the skin’s firm and elastic feel. This is why dermatologists prescribe topical creams, lotions or gels that contain some amount of anti-oxidants to control free radical formation and wrinkles.

Not All the Time

Free radicals are not all bad, however. That is because the body needs their services sometimes. There are certain white blood cells that release free radicals to kill bacteria invading the body. Another study suggests that low levels of free radicals actually help protect body cells.

Free Radicals vs. Antioxidants

The body needs antioxidants to counter the harmful activity of free radicals. Actually, the body has a defense system in place that protects the DNA and other important body cells. There are enzyme antioxidants, such as the superoxide dismutase, catalase and glutathione peroxidase, present in the body that neutralize free radicals.

In addition, the body needs antioxidant nutrients from food to help control free radicals. Antioxidant vitamins include vitamins A, C, E, and beta-carotene. The minerals selenium, manganese and zinc, though needed in minute quantities, are essential in activating enzyme antioxidants.

Many antioxidants which are not categorized under enzyme antioxidants and antioxidant nutrients have also been studied and found beneficial. These include coenzyme Q10, uric acid, phytochemicals, flavonoids, tannins, and resveratrol.

Most antioxidants are present in plant-based foods. Check out the table below to know which are antioxidant-rich foods and how they can potentially help the body.

Eat a variety of antioxidant-rich fruits and vegetables. Take only recommended doses of antioxidant supplements. Image modified by Chin chin

Eat a variety of antioxidant-rich fruits and vegetables. Take only recommended doses of antioxidant supplements. Image modified by Chin chin

Food Sources of Antioxidants and Potential Effects on the Body

Table of antioxidant, food sources and potential effects

AntioxidantFood sourcePotential effects on the body

Vitamin E

sunflower seeds, almonds, spinach, swiss chard, avocado, peanuts, turnip greens

Protect fats in LDL from oxidation. Safeguards cell membranes.

Vitamin C or ascorbic acid

Papaya, bell peppers, broccoli, brussel sprouts, strawberries, pineapples, oranges

Neutralize free radicals inside cell membranes; transforms iron to a form that is better absorbed in the intestines


carrots, sweet potatoes, spinach, collard greens, tomatoes, kale

Neutralizes free radicals with possible potential as anti-cancer & anti-aging compound; boosts immunity and reduces the risk of several diseases.


apples, apricots, pears, blueberries, raspberries, strawberries, parsley, cabbage, onions, olives, green teas, black tea, whole wheat products, wine, oregano, citrus fruits

Boost cellular anti-oxidant mechanisms, maintains brain function, contributes to brain and heart health, may also improve vision and urinary tract health.


red wine, red and purple grape juice, blueberries, cranberries, peanuts.

May protect the lining of heart vessels, may prevent inflammation, reduce low-density lipoprotein and formation of blood-clot.


Pomegranates, nuts, lentils, red and white wine, green tea.

Pomegranates, nuts, lentils, red and white wine, green tea.

Manganese and selenium

seafood and meat

Needed for enzyme antioxidant activation

Antioxidant Benefits and Drawbacks

Many articles have already been written about the health benefits of antioxidants. But let me honestly say that studies note a weak but measurable effect between eating antioxidant-rich foods and lowering the risk of cancer, heart disease, arthritis, stroke, cataract, Parkinson's, Alzheimer's and other diseases. Scientists are not able to fully explain how and why antioxidants are beneficial right now, but maybe sometime in the future.

Suffice to say, getting antioxidants from natural food sources is very much encouraged. The same, however, cannot be said of antioxidant supplements.

Why is that? Isn't increasing the dose of antioxidants more beneficial? Isn't it that more antioxidants mean more fighters against free radicals?

The research results on this query are mixed, but mostly disappointing. One study showed that increasing the intake of vitamin E and other antioxidant supplements by the participants did not really protect them from cancer or heart disease. There was even a study that showed an increase in the rate of lung cancer incidence with the intake of antioxidant supplements.

The only study that gave a positive result was the one on age-related eye disease. A combination of vitamin C, E, beta-carotene and zinc supplementation reduced the risk of age-related macular degeneration.

For more information on these antioxidant studies, refer to the links below.

Conclusion and Recommendations

To end the discussion on this controversial topic of antioxidants, here are my three recommendations:

  • Consume antioxidants mostly from natural sources. Include a variety of fresh fruits and vegetables in your diet. Bright orange, yellow, red, blue and purple fruits and vegetables are full of anti-oxidant properties. It is possible that some substances in the fruits and vegetables work in tandem with the antioxidants to make them effective in protecting the body.
  • When taking supplements, don't go for mega-doses of antioxidants as this may cause more toxic effects. There is such a thing called Recommended Dietary Allowance or RDA established by the Food and Nutrition Board. This is a guideline, which sets the maximum amount of a nutrient that healthy individuals can have each day without adverse effects on health. Vitamins and minerals are included in the list.
  • Individuals who are suffering from any health conditions should consult their doctor first before taking any supplement. Some actually think that it's all right to take these antioxidant supplements to aid their illness. But this is not always the case. In cancer patients, for example, it's possible that antioxidants will actually hinder the potency of chemotherapy and radiotherapy treatments. Such treatments, in fact, depend on the action of free radicals in destroying the cancer cells.

Readings on Antioxidant Studies

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.

© 2015 Chin chin


Chin chin (author) from Philippines on October 07, 2015:

I'm missing blueberries in my diet. We don't have it here in the Philippines. Thank you, BlossomSB for the visit.

Bronwen Scott-Branagan from Victoria, Australia on October 07, 2015:

An interesting article and good images. Umm! I love blueberries - think I'll just go and raid the fridge before I go to bed.