Everything you need to know about antioxidants

antioxidantsAntioxidants neutralize free radicals by altering their structure at the molecular level, preventing oxidative damage in the body.

Both antioxidants and free radicals are present in every living thing, though they are more abundant in plants than animals. We need both to keep our physical engine running smoothly. (1)

Maintaining an appropriate balance between the two is vital for good health. For example, free radicals (also called pro-oxidants, as opposed to anti-oxidants) are used by the immune system to wipe out bacteria that could cause infections. (2)

When the balance of free radicals and antioxidants gets out of whack, oxidative stress can occur. In a state of oxidative stress, molecules necessary for smooth function of various processes can be damaged. Cell death may also be triggered by imbalance.

Let’s take a detailed look at the mechanisms involved in balancing antioxidants and free radicals, starting at the molecular level.

How Antioxidants Work

Matter is made up of atoms; every atom has a core composed of neutrons and protons, with pairs of electrons revolving around this core in constant motion. Protons in the center carry a positive electrical charge, and electrons on the outer portion of the atom carry a negative charge.

Two or more atoms linked together make a molecule. Molecules joined together, whether it’s a dozen or a hundred, form the substances that make up our physical bodies, such as DNA, fats and proteins.

Chemical reactions that sustain life are known collectively as metabolism, and these reactions are what facilitate the structure and form of all organisms.

Metabolic action takes place in a variety of ways. Smaller molecules are grouped into larger molecules; bigger molecules are broken down to make smaller molecules.

Sometimes electrons revolving around atom cores go astray during these metabolic processes; these are meant to be paired, and when one of the two electrons is lost, the atom is unstable.

Then it can become a free radical, which has the potential of reacting with other molecules (like DNA) and damaging them. Chain reactions can also occur, transforming the affected cells into free radicals as well.

Antioxidant molecules “donate” an electron to replace the lost one, stabilizing the molecule so it can’t cause damage.

What Causes the Formation of Free Radicals?

Our bodies are designed to run smoothly, with electrons revolving in neat pairs while metabolic processes, like the combining and breaking down of molecule groups described above, take place.

But it doesn’t always work that way.

Here are some substances and circumstances that can cause the formation of too many free radicals, upsetting the balance:

  • Exercising too long and/or too hard, which damages tissues (3)
  • Smoking cigarettes
  • Excessive amounts of magnesium, iron, zinc or copper taken into the body
  • Drinking alcohol
  • Too much oxygen or too little oxygen in the body (4)
  • Air pollution and other environmental toxins
  • High levels of blood sugar (5, 6)
  • Radiation, including getting too much sun on the skin
  • Too much vitamin C or vitamin E (antioxidants) (7)
  • A deficiency of antioxidants (8)
  • Infections caused by viruses, fungi or bacteria

It’s easy to see how any of us might end up in a state of oxidative stress. When this continues for long periods of time, it may contribute to the aging process, as well as increasing the likelihood of developing cancer, heart disease or other health issues.

Antioxidants Are Everywhere

All life forms have defense mechanisms in place for protection against damage by free radicals. For example, the human body generates an antioxidant called glutathione at the cellular level.

Human life can’t exist without the presence of certain antioxidants, like vitamins C and E. While we get antioxidants from all the foods we eat, plants are much richer sources than animal foods like meat and fish. (9, 10)

This is why eating a diet with plenty of fruits, vegetables and other plant foods like nuts, grains and legumes yields a range of health benefits. (11) Berries are a particularly abundant source of antioxidants. (12)

Other good sources of antioxidants include dark chocolate, tea and coffee. Researchers have speculated that coffee may provide the majority of antioxidants in a typical Western diet. (13, 14) However, this could be because average consumption of antioxidant-rich foods is low in populations consuming such diets.

Antioxidants like vitamin C are often added to processed foods because they increase the shelf life in much the same manner as they help keep natural foods fresh for longer periods of time. (15)

Many Different Types of Antioxidants Are Found In Foods

Some antioxidants are water-soluble and some are fat-soluble: the water soluble ones do their work in fluids inside and outside cells; fat-soluble antioxidants perform actions mostly in cell membranes.

Vitamin C is among the most vital of water-soluble antioxidants; vitamin E is an important fat-soluble antioxidant, playing a role in the protection of cell membranes from oxidative damage.

Another group of antioxidants called flavonoids, which are abundant in many plant foods, have been associated with a decreased risk of coronary heart disease. (16)

Sometimes these antioxidants also serve other purposes that benefit health, like those found in olive oil and turmeric.

Extra virgin olive oil contains oleocanthal, which has powerful anti-inflammatory properties; the curcumins in turmeric are also known for their effectiveness in reducing inflammation. (17, 18)

Antioxidants are also available in supplement form, but as noted in the list above, excess antioxidants can cause problems, so this can be a case where more is not a good thing.

Part of the reason for this is that antioxidant supplements are made with isolated compounds, rather than the whole package delivered by real foods.

Isolating antioxidants from food sources removes them from the hundreds (or perhaps thousands) of other nutrients contained in the food, and all of these work together in the body to give it what it needs.

Toxic effects have been reported from taking high doses of antioxidant supplements; too much can actually increase the risk of death. (19, 20)

The safest and most effective way to get the antioxidants your body needs for optimal function is to make sure your diet includes a range of foods rich in these compounds. (21)

One study comparing the effects of blood orange juice and water with added vitamin C powder showed the antioxidant levels measured in participants drinking the juice were significantly higher. (22)

If you aren’t able to eat an assortment of healthy foods for some reason, adding a low-dose antioxidant supplement may be better than nothing.

Summary: Ensuring the balance of antioxidants and free radicals in your body by including natural, whole foods rich in these substances may be among the most important choices you can make to cultivate vital health and decrease your chances of developing chronic diseases.


  1. http://www.hindawi.com/journals/bmri/2014/761264/
  2. http://www.bloodjournal.org/content/92/9/3007
  3. http://www.ncbi.nlm.nih.gov/pubmed/18923182
  4. http://www.ncbi.nlm.nih.gov/pubmed/11948241
  5. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1448694/
  6. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC209408/
  7. http://www.hindawi.com/journals/bmri/2014/761264/
  8. http://www.ncbi.nlm.nih.gov/pubmed/9357853
  9. http://www.ncbi.nlm.nih.gov/pubmed/21684086
  10. http://www.ncbi.nlm.nih.gov/pubmed/22138166
  11. http://www.ncbi.nlm.nih.gov/pubmed/15159237
  12. http://www.ncbi.nlm.nih.gov/pubmed/20096093
  13. http://jn.nutrition.org/content/134/3/562.short
  14. http://www.ncbi.nlm.nih.gov/pubmed/14506489
  15. http://www.ncbi.nlm.nih.gov/pubmed/23501254
  16. http://www.ncbi.nlm.nih.gov/pubmed/23953879
  17. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3633300/
  18. http://www.ncbi.nlm.nih.gov/pubmed/21443487
  19. http://www.ncbi.nlm.nih.gov/pubmed/15464182
  20. http://www.ncbi.nlm.nih.gov/pubmed/15537682
  21. http://www.ncbi.nlm.nih.gov/pubmed/15159237
  22. http://www.ncbi.nlm.nih.gov/pubmed/17349075
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