Free Radicals, Oxidative Stress, & Antioxidants
Free Radicals & Oxidative Stress
Free radicals are unstable, high energy substances that attack DNA, proteins, and essential fats. Imagine free radicals like devastating missiles that strike their target and cause severe damage, impairing the function and viability of the target.
Frequently, free radicals contain either oxygen or nitrogen as their major component and are referred to as reactive oxygen species or reactive nitrogen species, respectively.
- Superoxide anion radical
- Hydrogen peroxide
- Hydroxyl radical
- Nitric oxide
- Peroxynitrate anion
Free radicals demonstrate varying degrees of potency with the superoxide anion and peroxynitrate anion displaying frightful destructiveness.
Surprisingly given their destructive nature, free radicals have a critical role in maintaining health and contribute vitally to immune system effectiveness:
- Free radicals offer a potent defense against invading organisms, such as bacteria, viruses, and parasites.
- Free radicals boost the cellular repair process by demolishing injured cell structures; paving the way for the new growth.
- Free radicals help rid the body of diseased cells, such as cancer cells.
But as many things in complex biologic systems there is a fine balance between too much and too little. Too little free radicals and the body is at risk for overwhelming infection; too many free radicals and the body is at risk for significant collateral damage to normal healthy tissue, referred to as oxidative stress.
Oxidative stress is a situation in which free radicals attack healthy cells, healthy proteins, and healthy fats. Many diseases have been linked to oxidative stress and excessive free radical production. Examples include:
- Osteoporosis (weak bones)
- Arthritis (joint disease)
- Sarcopenia(muscle loss and weakness)
- Heart Disease
In addition to their injurious nature, free radicals play a key role in initiating and propagating inflammation. Chronic inflammation is a known risk factor for chronic disease.
Indisputably, a multi-pronged defense against uncontrolled free radical generation and oxidative stress is essential for well being.
An antioxidant is any substance that helps protect the body against damage inflicted by free radicals. An antioxidant’s mechanism of action usually falls into one of the following categories:
- Stops the formation of free radicals.
- Transforms free radicals into less dangerous substances.
- Scavenges and completely neutralizes free radicals.
The body has developed natural defenses to protect against oxidation and to promote well being. The body employs a network of enzymes, vitamins, and other substances to afford protection:
- Enzymes(Superoxide dismutase, catalase, glutathione peroxidase…)
- Vitamins(Vitamin C, vitamin E, vitamin A…)
- Other Substances(Uric acid, glutathione…)
Additionally, the plant kingdom has developed powerful substances that protect against oxidative stress and free radical damage. Some examples are:
- Essential oils
- Organo sulfur compounds
By consuming an abundant and diverse array of health promoting antioxidants we are able to protect against free radical damage, oxidative stress, and disease.
Miguel, M.G. Antioxidant activity of medicinal and aromatic plants. Flavour Fragr. J. 2010, 25, 291-312.
Maestri, D.M.; Nepote, V.; Lamarque, A.L.; Zygadlo, J.A. Natural products as antioxidants. In Phytochemistry: Advances in Research; Imperato, F., Ed.; Research Signopost: Kerala, India, 2006; pp. 105-135.
Aruoma, O.I. Free radicals, oxidative stress, and antioxidants in human health and disease. J. Am.Oil Chem. Soc. 1998, 75, 199-212.
Fridovich, I. Superoxide anion radical (O2•-), superoxide dismutases, and related matters. J. Biol. Chem. 1997, 272, 18515-18517.
Chen, S.-X.; Schopfer, P. Hydroxyl-radical production in physiological reaction. A novel function of peroxidase. Eur. J. Biochem. 1999, 260, 726-735.
Kostka, P. Free radicals (nitric oxide). Anal. Chem. 1995, 67, 411R-416R.
Karadag, A.; Ozcelik, B.; Saner, S. Review of methods to determine antioxidant capacities. Food Anal. Methods 2009, 2, 41-60.
Niki, E. Assessment of antioxidant capacity in vitro and in vivo. Free Radic. Biol. Med. 2010, 9, 503-515.
Aruoma, O. I. (1994). Nutrition and health aspects of free radicals and antioxidants. FoodChemistry and Toxicology, 32, 671–683.
Asensi-Fabado, M. A., & Munne´-Bosch, S. (2010). Vitamins in plants: Occurrence, biosynthesis and antioxidant function. Trends in Plant Science, 15, 582–592.