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Antioxidants

Antioxidants
You’ve probably heard the term antioxidants bandied about by health experts. You know they’re good for you. But how exactly do they work and how should you add them to your diet?

Do you need to supplement with them? And can you get too many? Well there is a lot of science to answer this.

What are Antioxidants and Free Radicals?

The first thing you need to understand is how free radicals and the process of oxidation affect your body.

Your body is made of many different types of cells. Cells are made of molecules. Molecules consist of one or more atoms of one or more elements joined by chemical bonds.

As you may (or may not) remember from high school chem class, atoms consist of a nucleus, neutrons, protons and electrons. The number of protons (positively charged particles) in the atom’s nucleus determines the number of electrons (negatively charged particles) surrounding the atom.

Free radicals are atoms or groups of atoms with an odd (unpaired) number of electrons and can be formed when oxygen interacts with certain molecules. When an atom is “missing” a needed electron it’s unstable – as if it’s declared a State of Emergency. It will immediately attempt to replace it, even if it means “stealing” an electron from another atom. This can start a chain reaction, like dominoes.[1]

Their chief danger comes from the damage free radicals can do when they react with important cellular components such as DNA, or the cell membrane. Cells may function poorly or die if this occurs. The damage this causes accumulates as we age.[2]

Antioxidants To The Rescue

Antioxidants neutralize free radicals by donating one of their own electrons, ending the electron-”stealing” reaction. They act as scavengers, helping to prevent cell and tissue damage that could lead to cellular damage and disease.[3]

Antioxidants are divided into two classes: water-soluble and lipid-soluble. In general, water-soluble antioxidants react with free radicals in the blood plasma and in the liquid area inside cells, while lipid (or fat)-soluble antioxidants protect the cell walls from this damage.[4]

Dangers of Oxidative Stress

“Oxidative Stress” is the term used to explain the buildup of damage to cells caused by free radicals. This damage has been linked to diseases such as:

  • Alzheimers and Parkinsons Diseases[5]
  • Complications from Diabetes[6]
  • Resistance and the development of diabetes[7]
  • Cardiovascular diseases[8]
  • Age-related Macular Degeneration[9]
  • Many forms of Cancer[10]

The theory that oxidative stress may in fact be a root cause of many of the above diseases – especially for the link between metabolic issues and cardiovascular problems – continues to gain acceptance.[11] One reason for this is the chronic inflammation oxidative stress causes.

Benefits of Antioxidants

There are so many different types of antioxidants (see below) that it’s really hard to list all the benefits they’ve been found to deliver. Wherever possible we’ve linked to articles we have on each individual antioxidant and their benefits below.

Sources of Antioxidants

One important source of antioxidants is the food we eat. Fresh fruits and vegetables, as well as minimally processed whole grains provide what is known as micronutrient antioxidants. For most people, this is the primary source of the antioxidants their body will use.

But few people eat enough – or enough of a variety of – natural foods to supply the antioxidants necessary for optimal health. Below are some sources, both from foods and supplements, for effective antioxidants:

Vitamin C – water soluble vitamin present in citrus fruits and juices, green peppers, cabbage, spinach, broccoli, kale, cantaloupe, kiwi, and strawberries.[12]

Vitamin E – A lipid soluble vitamin present in nuts, seeds, vegetable and fish oils, whole grains (esp. wheat germ), fortified cereals, and apricots.[13]

Beta-Carotine – is a lipid soluble precursor to vitamin A (retinol) and is present in liver, egg yolk, milk, butter, spinach, carrots, squash, broccoli, yams, tomato, cantaloupe, peaches, and grains.[14]

Polyphenols – These are usually plant-based, specifically plants with phytochemical or darkly-colored properties. Chocolate, tea, blueberries, red wine, sea buckthorn, pomegranite, etc. There are over 4,000 distinct species, and not all have been documented beneficial.[15] These often fall into the water soluble category.

Astaxanthin – Technically a carotinoid (a form of beta-carotine) astaxanthin deserves special mention for three reasons: 1, it is not converted to vitamin A in the body as most carotinoids are (too much vitamin A can be toxic)[16] and 2, its antioxidant capacity is the strongest of all carotinoids previously studied,[17] and 3, it’s lipid-soluble nature contributes to it’s rare capacity to pass both the blood-brain and blood-retinal barriers.[18] While it is present in small amounts in shrimp and salmon (and responsible for their orange-pink color) it is difficult to consume meaningful amounts this way. Supplement sources include algae and krill oil.

You’ve probably heard the term antioxidants bandied about by health experts. You know they’re good for you. But how exactly do they work and how should you add them to your diet?
Do you need to supplement with them? And can you get too many? Well there is a lot of science to answer this.

What are Antioxidants and Free Radicals?

The first thing you need to understand is how free radicals and the process of oxidation affect your body.
Your body is made of many different types of cells. Cells are made of molecules. Molecules consist of one or more atoms of one or more elements joined by chemical bonds.
As you may (or may not) remember from high school chem class, atoms consist of a nucleus, neutrons, protons and electrons. The number of protons (positively charged particles) in the atom’s nucleus determines the number of electrons (negatively charged particles) surrounding the atom.


  1. ^ Hayyan M., Hashim M.A., AlNashef I.M., Superoxide Ion: Generation and Chemical Implications, Chem. Rev., 2016, 116 (5), pp 3029–3085. DOI: 10.1021/acs.chemrev.5b00407]
  2. ^ Halliwell, Barry, and John MC Gutteridge. Free radicals in biology and medicine. Oxford University Press, USA, 2015.
  3. ^ Valko, Marian, et al. “Free radicals and antioxidants in normal physiological functions and human disease.” The international journal of biochemistry & cell biology 39.1 (2007): 44-84.
  4. ^ Sies, Helmut. “Oxidative stress: oxidants and antioxidants.” Experimental physiology 82.2 (1997): 291-295.
  5. ^ Jomova, Klaudia, et al. “Metals, oxidative stress and neurodegenerative disorders.” Molecular and cellular biochemistry 345.1-2 (2010): 91-104.
  6. ^ Giacco, Ferdinando, and Michael Brownlee. “Oxidative stress and diabetic complications.” Circulation research 107.9 (2010): 1058-1070.
  7. ^ Ceriello, Antonio, and Enrico Motz. “Is oxidative stress the pathogenic mechanism underlying resistance, diabetes, and cardiovascular disease? The common soil hypothesis revisited.” Arteriosclerosis, thrombosis, and vascular biology 24.5 (2004): 816-823.
  8. ^ Griendling, K. K., and R. W. Alexander. “Oxidative stress and cardiovascular disease.” Circulation96.10 (1997): 3264-3265.
  9. ^ Bailey, Tracey A., et al. “Oxidative stress affects the junctional integrity of retinal pigment epithelial cells.” Investigative ophthalmology & visual science 45.2 (2004): 675-684.
  10. ^ Valko, Marian, et al. “Free radicals, metals and antioxidants in oxidative stress-induced cancer.” Chemico-biological interactions 160.1 (2006): 1-40.
  11. ^ Holvoet, Paul. “Relations between metabolic syndrome, oxidative stress and inflammation and cardiovascular disease.” Verh K Acad Geneeskd Belg 70.3 (2008): 193-219.
  12. ^ Bendich, A., et al. “The antioxidant role of vitamin C.” Advances in Free Radical Biology & Medicine2.2 (1986): 419-444.
  13. ^ Traber, Maret G., and Jeffrey Atkinson. “Vitamin E, antioxidant and nothing more.” Free Radical Biology and Medicine 43.1 (2007): 4-15.
  14. ^ Burton, G. Wand, and K. U. Ingold. “Beta-carotene: an unusual type of lipid antioxidant.” Science224.4649 (1984): 569-573.
  15. ^ Scalbert, Augustin, Ian T. Johnson, and Mike Saltmarsh. “Polyphenols: antioxidants and beyond.” The American journal of clinical nutrition 81.1 (2005): 215S-217S.
  16. ^ Hathcock, John N., et al. “Evaluation of vitamin A toxicity.” The American journal of clinical nutrition52.2 (1990): 183-202.
  17. ^ Naguib, Yousry MA. “Antioxidant activities of astaxanthin and related carotenoids.” Journal of agricultural and food chemistry 48.4 (2000): 1150-1154.
  18. ^ Liu, Xuebo, and Toshihiko Osawa. “Astaxanthin protects neuronal cells against oxidative damage and is a potent candidate for brain food.” Food Factors for Health Promotion. Vol. 61. Karger Publishers, 2009. 129-135.
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