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Antioxidants and free radicals


Free Radicals

Free radicals are "single charged", unpaired electrons that are very active and always ready to steal other electronics, causing oxidation. Types of free radicals include the hydroxyl radical (OH.), the superoxide radical (O.2), the nitric oxide radical (NO.) and the lipid peroxyl radical (LOO.).

These atoms with single-charged, unpaired electrons are chemically very active due to their instability. These free radicals are always in search of stabilizing themselves by undergoing chemical reaction with other atoms and molecules. They rob other atoms of their electrons in order to stabilize themselves and in this way oxidation reaction takes place. An example of the oxidation of iron is the change of color of slice of apple, which turns brown, soon after it is cut. The apple slice cut and placed in open air undergoes oxidation and its color changes to brown after a short time. The resulting brownish discoloration is because of the oxide thus formed.

The free radicals play an important role in many life sustaining processes. For instance, free radicals help in phagocytosis of bacteria, viruses and other pathogens by white blood cells. These white blood cells produce active specie of oxygen as part of microbiocidal and citocidal processes. Thus free radicals help white blood cells to eliminate foreign invading organisms.

Antioxidant Defense

An antioxidant is a molecule capable of slowing or preventing the oxidation of other molecules, especially free radicals. In 1954, Denham Harman, found that free radicals accelerate aging process. However, biologial systems and processes have their own protective mechanisms against damaging effects of activated species or free radicals. Free radical scavangers, chain reaction terminators, e.g., SOD and glutathione peroxidase system, and "solid state" defense, including melanins, help do away with the damaging effects of free radicals to some extent. 

The way free radicals are tamed is that chemical oxidant donate electron to free radical and convert it to non-radical form.

Melanin is, on the other hand, a stable radical former. It would scavenge old electrons to form stable radical specie after terminating radical chain reaction.

Causes and sources of Free Radical Formation

Internal Sources
  • Metabolic Processes - a continuous process
During the process of energy production by cells, i.e., ATP formation, 4% of oxygen used ends up into free radical formation. Superoxide anion formed in the process is free radical and a reactive oxygen specie. Thus free radicals are in a way by products of metabolic processes. 
  • Inflammatory Processes
When body suffers from inflammations or infections, the white blood cells are produced in abundance in order to kill viruses, bacteria and other pathogens. In this process they produce free radicals.

External and Environmental sources

The environmental causes of free radical formation include smoking, radiation or ultraviolet rays, electromagnetic waves, environmental pollution - pesticides, heavy metals -  and food preservatives, etc.
  • Smoking
Smoking, including passive smoking, can cause formation of free radicals. According to one estimate, one cigarette smoked can produce 100 trillion free radicals! (Source: Society for Free Radical Research). 
  • Radiation, Ultraviolet ray, electromagnetic waves
For instance, radiotherapy, sunburn, etc can cause free radical formation.
  • Environmental pollution
Air pollution, pollution of drinking water, pollution from industrial waste, soil pollution, can also cause free radical formation in human bodies.
  • Chemicals and medicines
Food additives, preservatives, overdose of medicines, e.g., antibiotics, can cause free radical formation as well.
  • Emotional conditions
Stress, anxiety, depression, impatience, nervousness and other emotional conditions may also lead to free radical formation.

Each cell of human body is exposed to 10 billion molecules of Superoxide every day, under normal metabolic conditions (Source: Linus Pauling Institute). For instance, if a person's weight is 68 kg, (s)he would be exposed to estimated 1,800 g of superoxide in any one year.

More than one hundred chronic diseases are said to be, directly or indirectly, related to adverse effects of free radicals. Oxidation process may lead to disease or disease related bypass.  It is here where anti-oxidants play their role.

Free Radicals' threat to health

According to Society for Free Radical Research, Malaysia, 32,000 people die of free radical related diseases (Tan Sri Datuk Dr Augustine S. H. Ong, "Threat of Free Radicals", Society for Free Radical Research ASEAN/Malaysia). Furthermore, each human cell is attacked 73,000 times by free radicals every day.

Diseases which may possibly be caused by free radicals excess in body include: Cancer,Heart disease, Stroke, Alzheimers, Parkinsons, Enlarged Prostate, Polysitic Ovarian syndrome, MS, Bowel cancer, Fibromyalgia, Diabetes, Auto-immune diseases, Infertility, Crohn’s, Diverticulitis, Chronic fatigue, Osteo-Arthritis, Ulcerative colitis, Endometriosis, Diabetes, Dental problems, Lupus, Raynauds, Allergies, Cataracts, Rheumatoid Arthritis, Sinusitis, Peptic Ulcer, Bowel cancer, Hypertension, and Chronic depression.

Cancers

Cancers are caused by uncontrolled cell division leading to tumors formation. The cancer cells compete with the normal cells for nutrition and thus normal cells' growth and development is retarded or inhibited. cancer cells themselves would spread to different parts of body and start growing there, thereby damaging all these parts of body where they spread.

In 1989, famous nobel prize winning Professors Harold E. Varmus and J. Michael Bishop found that   gene mutations in normal cell DNA is responsible for triggering the cancer growth in normal cells. These transformations take place when genes are exposed to carcinogens (cancer causing substances). Thus every human being is a potential candidate for being affected by cancer. The chance of getting cancer can be reduced by reducung the exposure of carcinogens. Unfortunately free radicals are also carcinogens and their exposure to cell DNA needs to be reduced.

Free radical damage to Cell

  1. Free radicals can affect human cells greatly and can cause cell death straight away.
  2. Free radicals can cause mutations in genes which can lead to cancer formation.
Cardiovascular disease and free radicals

Mainly Cardiovascular Diseases and cerebrovascular diseases are result of narrowing blood vessels of heart and brain. The narrowing results from deposition of arteriosclerotic plaque. Arteriosclerosis is direct result of free radical oxidation.

Arteriosclerosis

There are to types of lipoproteins in the body (1) Low Density Lipoproteins (LDL) and (2) High density Lipoproteins (HDL). The HDLs are considered to be "good" lipoproteins (or good cholesterol). The LDL, after series of changes converts to bubble-like substances. These substances accumulate causing narrowing of blood vessels. The narrowing progresses and blocks the blood vessels completely in extreme cases. These accumulating substances can also detach leading to transformation into blood clots or infarctions. If this occurs in coronary arteries, it can lead to myocardial infarction (Heart Attack) and if this occurs in cerebral arteries, stroke may result. 

Oxidative stress after re-perfusion

Once stroke has occured, the re-perfusion of the affected tissue leads to formation of more free radicals. Furthermore, the body's own white blood cells, which invade the damaged tissues will lead to formation of still more free radicals.

Free radicals produced by White Blood Cells may also cause certain diseases. For instance, free radicals may affect and damage beta cells of the Islets of Langerhans in pancreas to cause abnormalities in sugar metabolism and hence diabetes mellitus. 

Free radicals and Parkinson's Disease

Parkinson's disease is a disorder that affects nerve cells, or neurons, in a part of the brain that controls muscle movement. In Parkinson's, neurons that make a chemical called dopamine die or do not work properly. Parkinson's disease manifests results in trembling of hands, arms, legs, jaw and face; stiffness of the arms, legs and trunk; slowness of movement, poor balance and coordination. (More at MedlinePlus)

Why the neurons that make dopamine die? According to one theory these neurons die because of unstable and potentially damaging molecules - free radicals - generated by normal chemical reactions in the body.  

One can find many references regarding involvement of such oxidative stress in pathobiochemistry of Parkisnon's Disease. Journal of Neurology published a study (Koutsilieri E, Scheller C, Grünblatt E, Nara K, Li J, Riederer P., 2002 Sep;249 Suppl 2:II1-5; PMID: 12375056) which concludes: "a great body of evidence points to the view that OS [oxidative stress] is a major component underlying the pathobiochemistry of PD [Parkinson's Disease]. Together a genetic disposition and endogenous/exogenous toxic events of various origins result in a synergistic cascade of toxicity which leads to dysfunction and finally to cell death of dopaminergic neurons. Again, OS plays a significant role in generating cell death signals including apoptosis."

Free radicals, eye function and cataracts

According to research article from Medscape/WbMD, written by Pierfrancesco Morganti, PhD; Giuseppe Fabrizi, MD; Cesare Bruno, "the stratum corneum is exposed to a peroxidative environment that includes air pollutants and ultraviolet (UV) solar light.[Witt EH, Motchnick P, Packer L. Evidence for UV light as an oxidative stressor in skin. In: Fuchs J, Packer L, eds. Oxidative Stress in Dermatology. New York, NY: Dekker; 1993. Thiele JJ, Podda M, Packer L. Tropospheric ozone an emerging environmental stress to skin. Biol Chem. 1997;378:1299-1305. Weber SU. Oxidants in skin pathophysiology. In: Sen CK, Packer L, Haimmen O, eds. Exercise and Oxygen Toxicity. 2nd ed. Philadelphia, PA: Elsevier Science; 1999.Free radicals play an important role in skin aging and in the pathogenesis of several human diseases, such as coronary heart disease, cataractogenic process, and skin cancer.[Halliwell B, Gutteridge JMC. Free Radicals in Biology and Medicine. 3rd ed. New York, NY: Oxford University Press; 1998. Wiseman H, Goldfarb P, Ridway T, et al. Biomolecular Free Radical Toxicity: Causes and Prevention. London, England: J Wiley Ltd; 2000. Thiele JJ, Dreher F, Packer L. Antioxidant defense systems in skin. In: Elsner P, Maibach H, eds. Drugs vs. Cosmetics: Cosmeceuticals? New York, NY: Dekker; 2000:145-188.] 

Free radicals, skin aging and skin cancer

By googling and PubMed search, one can find large number of articles pertaining to effects of free radicals on the skin's aging process. According to Free Radical Research Group, University of Paris, France, "Cutaneous aging is the result of genetically determined or intrinsic aging superimposed by degenerative changes due to actinic irradiation, also called photoaging. The manifestations of cutaneous aging, as it relates to the perception of age, is caused by ultraviolet light, in particular in those parts of the body exposed daily to solar radiation. Free radical generation in the skin by UV light and from other sources..." The research article further adds: "The decrease in antioxidant enzymes and small molecular weight antioxidants such as glutathione, vitamin E and ubiquinone upon exposure to UV light is an indication that the pro-antioxidant balance can be overwhelmed by acute or chronic photo-oxidative stress. Antioxidant supplementation is therefore a means for prevention or at least retardation of premature cutaneous aging" (PMID: 1450595)

As its now known that ultraviolet radiations are the major creators of free radicals, which are unstable oxygen molecules with only one electron instead of two and because electrons are found in pairs, the molecule must scavenge other molecules for another electron. When the 2nd molecule looses its electron to the 1st molecule, it must then find another electron repeating the process. This process can damage cell function and bring about changes in genetic material, RNA and DNA. Free radical damage causes wrinkles by activating the metalloproteinases that break down collagen. They can cause cancer by changing the cellular genetic material, RNA and DNA.

According to National Cancer Institute, USA, "When an oxygen molecule (O2) becomes electrically charged or “radicalized” it tries to steal electrons from other molecules, causing damage to the DNA and other molecules. Over time, such damage may become irreversible and lead to disease including cancer."  In case of skin, the cell DNA is affected by these free radicals, especially those being produced due to ultra-violet light and reactive oxygen species. 

Hanson Kerry M.; Gratton Enrico; Bardeen Christopher J. carried out research in 2006, published under title "Sunscreen enhancement of UV-induced reactive oxygen species in the skin" in Free Radical Biology and Medicine 41 (8): 1205–1212, found that that the absorption of three sunscreen ingredients into the skin, combined with a 60-minute exposure to UV, leads to an increase of free radicals in the skin, if applied in too little quantities and too infrequently... However, they found that newer creams may not contain these specific compounds. 

Free Radicals, rheumatism and inflammatory diseases

F Brenbaum, Department of Rheumatology, Hopital Saint Antoine, Paris, while reviewing the book "Free Radicals and Inflammation", writes: "Searches for key words such as "reactive oxygen species and inflammation" in the PubMed database turn up 1000 papers - 900 of which will have been written within the past 10 years! It is obvious that oxidative stress is involved in the pathogenesis of human inflammatory diseases. However, these systems are complex, and there is increasing evidence that reactive oxygen species also play a part in almost every stage of the body's defence and repair processes" (Annals of the Rheumatic DiseasesBritish Medical Journal).

"Free Radicals and Inflammation" is written by P G Winyard, D R Blake, C H Evans. It is very good book on the subject and deals with the role of both oxygen- and nitrogen-centred free radicals in inflammatory diseases such as rheumatoid arthritis. Involvement of the superoxide anion radical in the bactericidal action of inflammatory cells is well known. It suggests that free radicals and the inflammatory response are inextricably linked. The widespread involvement of radicals in human disease seems inevitable, because inflammation is such a conspicuous component of human disease.

The book integrates contributions from leading research groups who have been investigating the role of radicals within the context of all stages of inflammation, such as the recruitment of inflammatory cells, their bactericidal action, inflammatory tissue destruction and inflammatory cell death by apoptosis. 

Copper-zinc protein obtained from bovine liver was found to have anti-inflammatory properties because it scavanges for superoxide-free radicals. This discovery led to the concept of free radical-mediated damage as a mechanism underlying inflammation. Peter C. Bragt of Medical Biological Laboratory, The Netherlands Organization of Applied Scientific Research (TNO), Rijswijk, The Netherlands, got published a research paper "Free radicals as a target of anti-rheumatic drug therapy" In this paper, published in journal "Inflammation & Research", he discusses some recent advances in this fascinating area of research. 

Free Radicals and pulmonary emphysema

Cigarette smoke inactivates alpha 1-antitrypsin in lungs which promotes proteolytic injury to lung tissue. This extracellular proteolysis is hypothesized to be the major cause of pulmonary emphysema and oxygen-derived free radicals and neutrophil elastase are thought to play an important role in its pathogenesis. [Kanazawa H, Kurihara N, Hirata K, Fujimoto S, Takeda T. First Department of Internal Medicine, Osaka City University Medical School, Japan; "The role of free radicals and neutrophil elastase in development of pulmonary emphysema"; Intern Med. 1992 Jul;31(7):857-60]. For details of this study, please visit PubMed (PMID: 1333306). 

Daniela Volonte‡, Beth Kahkonen§, Steven Shapiro¶, YuanPu Di§ and Ferruccio Galbiati‡1 of Departments of ‡Pharmacology and Chemical Biology, §Environmental and Occupational Health, and ¶Medicine, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania  published a research study in the Journal of Biological Chemistry (December 22, 2008, doi: 10.1074/jbc.C800225200; February 27, 2009). According to its findings, "Free radicals play a role in aging and age-related human diseases, including pulmonary emphysema. Cigarette smoke represents a source of oxidants and is considered an environmental hazard that causes pulmonary emphysema".  For study abstract, please check out Journal of Biological Chemistry

The use of antioxidants may thus have a role to prevent this condition.

Free Radicals and aging process

Dr. Denham Harman, M.D., Ph.D., was the first scientist to propose theory of aging. According to him, the indiscriminate chemical reactivity of free radicals possibly lead to random biological damage. This proposition is now considered a major theory of aging. The theory implies that antioxidants (for instance, vitamins E and C), which prevent free radicals from oxidizing (removing electrons from) sensitive biological molecules, slows the aging process. Dr. Harman launched his proposition by demonstrating, for the first time, that by feeding a variety of antioxidants to mammals, their life span can be extended.

Harman D.writes in the "The aging process" published in the Proceedings of the National Acadamy of Science, U S A. (1981 Nov;78(11):7124-8), "Aging is the progressive accumulation of changes with time that are associated with or responsible for the ever-increasing susceptibility to disease and death which accompanies advancing age. These time-related changes are attributed to the aging process. The nature of the aging process has been the subject of considerable speculation. Accumulating evidence now indicates that the sum of the deleterious free radical reactions going on continuously throughout the cells and tissues constitutes the aging process or is a major contributor to it." 
The study further concludes "In mammalian systems the free radical reactions are largely those involving oxygen. Dietary manipulations expected to lower the rate of production of free radical reaction damage have been shown (i) to increase the life span of mice, rats, fruit flies, nematodes, and rotifers, as well as the "life span" of neurospora; (ii) to inhibit development of some forms of cancer; (iii) to enhance humoral and cell-mediated immune responses; and (iv) to slow development of amyloidosis and the autoimmune disorders of NZB and NZB/NZW mice." 

In addition, studies strongly suggest that "free radical reactions play a significant role in the deterioration of the cardiovascular and central nervous systems with age. The free radical theory of aging provides reasonable explanations for age-associated phenomena, including (i) the relationship of the average life spans of mammalian species to their basal metabolic rates, (ii) the clustering of degenerative diseases in the terminal part of the life span, (iii) the beneficial effect of food restriction on life span, (iv) the greater longevity of females, and (v) the increase in autoimmune manifestations with age. It is not unreasonable to expect on the basis of present data that the healthy life span can be increased by 5-10 or more years by keeping body weight down, at a level compatible with a sense of well-being, while ingesting diets adequate in essential nutrients but designed to minimize random free radical reactions in the body." Abstract of this study is available on National Library of Medicine web site. PMID: 6947277 [PubMed - indexed for MEDLINE] 

Byung Pal Yu has came up with a nice book named, "Free Radicals in Aging". The author examins the role of free Radicals in the aging proces. He presents new findings regarding the involvement of free radicals in the aging process. The book covers the basic elements of free radical biochemistry, free radicals in cellular damage, anti-oxidant defenses, implications of free radicals in a variety of age-related diseases, and future directions of free radicals in gerontology. The book also discusses the effects of exercise on free radicals and the aging process. Free Radicals in Aging is an excellent reference for gerontologists, pathologists, and other researchers interested in this increasingly important topic.

Free Radicals and lung aging

The maximum capacity of the lungs may decrease as much as 40 percent between ages 20 and 70. Pérez R, López M, Barja de Quiroga G. of Department of Animal Biology-II (Animal Physiology), Faculty of Biology, Complutense University, Madrid, Spain published his research findings in "Free Radical Biology and Medicine" (1991;10(1):35-9). According o him although lung aging is not accelerated during old age due to a decrease in the antioxidant capacity of the tissue, nevertheless, findings are compatible with a continuous damage of the lung tissue by free radicals throughout the life span. (Full abstract on PubMed)

Kazuhiro Ito, PhD* and Peter J. Barnes, MD, FCCP of National Heart and Lung Institute, Imperial College School of Medicine, London, UK, published their research findings in "Chest" (2009 Jan;135(1):173-8) under title "COPD as a disease of accelerated lung aging". They found that there is increasing evidence for a close relationship between aging and chronic inflammatory diseases. COPD is a chronic inflammatory disease of the lungs, which progresses very slowly and the majority of patients are therefore elderly."

According to them there is evidence that the accelerated "aging of lung in response to oxidative stress is involved in the pathogenesis and progression of COPD, particularly emphysema. Aging is defined as the progressive decline of homeostasis that occurs after the reproductive phase of life is complete, leading to an increasing risk of disease or death. This results from a failure of organs to repair DNA damage by oxidative stress (nonprogrammed aging) and from telomere shortening as a result of repeated cell division (programmed aging). During aging, pulmonary function progressively deteriorates and pulmonary inflammation increases, accompanied by structural changes, which are described as senile emphysema. Environmental gases, such as cigarette smoke or other pollutants, may accelerate the aging of lung or worsen aging-related events in lung by defective resolution of inflammation, for example, by reducing antiaging molecules, such as histone deacetylases and sirtuins, and this consequently induces accelerated progression of COPD." (Published in "Chest" PMID: 19136405 [PubMed - indexed for MEDLINE].

Heart Aging

Heart disease is a leading cause of death. The muscles of heart thickens with age and as we age, our heart compensates for clogged arteries by working harder and raising blood pressure. These changes put the heart at risk and impact our quality of life. No one can deny fact that 40 percent of deaths for people aged 65 to 74 are from heart disease and this figure jumps to 60 percent for those over 80. As we age, our arteries become stiffer and less flexible causing our blood pressure to increase. The heart has to adjust to the increase in blood pressure by pumping harder and changing the timing of its valves. These adjustments leave the heart more vulnerable. 

  • With increasing age, the left ventricle of the heart also becomes thicker. This thickening allows the heart to pump stronger. However, blood vessels of the heart become narrower with the age causing blood pressure to increase. This narrowing results in decreased blood flow to the thickened ventricular muscles, thus can result in ischemic heart disease. 
  • With growing age, mitral valve also become thicker and move slowly. 
  • With increasing age, heart becomes less able to respond rapidly to chemical messages from the brain, thus decreasing the exercise capacity of the body. 
  • This shows up as shortness of breath -- a sign that oxygen-rich blood is not moving fast enough through the body because the lungs are trying to breath in more oxygen.
  • With age, fibrous tissue and fatty deposits builds up on the on nerves connecting the heart and brain thus heart-brain communication becomes slower, resulting in slower heart rate.
  • Increase in diastolic blood pressure stretches ventricles from inside with each beat giving a stronger pump in order to have a stronger contraction to pump the excess blood volume (Frank-Starling mechanism). However, because of greater diastolic pressure, the heart can't squeeze as tightly.
  • The heart of a healthy 70-year-old has 30 percent fewer cells than a 20-year-old's heart. When heart cells die, the other cells must stretch and grow to stay connected. An older person's heart cells may be up to 40 percent larger than a younger persons.
Thus by slowing the aging processes in heart, one can attempt to prevent premature heart failure. Antioxidants provide good support in such cases. 

Free radicals, reproductive health and infertility

Ashok Agarwal,Sajal Gupta,and Rakesh K Sharma1 of Center for Advanced Research in Human Reproduction, Infertility, and Sexual Function, Glickman Urological Institute and Department of Obstetrics-Gynecology; The Cleveland Clinic Foundation, Cleveland, Ohio, USA has given a very nice literature review on the role of "Role of oxidative stress in female reproduction". 

According to the review, "in a healthy body, ROS (reactive oxygen species) and antioxidants remain in balance. When the balance is disrupted towards an overabundance of ROS, oxidative stress (OS) occurs. OS influences the entire reproductive lifespan of a woman and even thereafter (i.e. menopause). OS results from an imbalance between prooxidants (free radical species) and the body's scavenging ability (antioxidants)."

"ROS affect multiple physiological processes from oocyte maturation to fertilization, embryo development and pregnancy. It has been suggested that OS modulates the age-related decline in fertility. It plays a role during pregnancy and normal parturition and in initiation of preterm labor."

Regarding cancer development, the review mentions, "Most ovarian cancers appear in the surface epithelium, and repetitive ovulation has been thought to be a causative factor. Ovulation-induced oxidative base damage and damage to DNA of the ovarian epithelium can be prevented by antioxidants.

The review further states, "There is growing literature on the effects of OS in female reproduction with involvement in the pathophsiology of preeclampsia, hydatidiform mole, free radical-induced birth defects and other situations such as abortions. Numerous studies have shown that OS plays a role in the pathoysiology of infertility and assisted fertility. There is some evidence of its role in endometriosis, tubal and peritoneal factor infertility and unexplained infertility. 

The article also reviews the role OS plays in normal cycling ovaries, follicular development and cyclical endometrial changes. It also discusses OS-related female infertility and how it influences the outcomes of assisted reproductive techniques. The review comprehensively explores the literature for evidence of the role of oxidative stress in conditions such as abortions, preeclampsia, hydatidiform mole, fetal embryopathies, preterm labour and preeclampsia and gestational diabetes. The review also addresses the growing literature on the role of nitric oxide species in female reproduction. The involvement of nitric oxide species in regulation of endometrial and ovarian function, etiopathogenesis of endometriosis, and maintenance of uterine quiescence, initiation of labour and ripening of cervix at parturition is discussed. Complex interplay between cytokines and oxidative stress in the etiology of female reproductive disorders is discussed. Oxidant status of the cell modulates angiogenesis, which is critical for follicular growth, corpus luteum formation endometrial differentiation and embryonic growth is also highlighted in the review. Strategies to overcome oxidative stress and enhance fertility, both natural and assisted are delineated. Early interventions being investigated for prevention of preeclampsia are enumerated. Trials investigating combination intervention strategy of vitamin E and vitamin C supplementation in preventing preeclampsia are highlighted. Antioxidants are powerful and there are few trials investigating antioxidant supplementation in female reproduction. However, before clinicians recommend antioxidants, randomized controlled trials with sufficient power are necessary to prove the efficacy of antioxidant supplementation in disorders of female reproduction. Serial measurement of oxidative stress biomarkers in longitudinal studies may help delineate the etiology of some of the diosorders in female reproduction such as preeclampsia. (Full review is available on PubMed Central.

Need to decrease the damaging effects of free radicals

As its clear that free radical damage to human cells can end up causing various health problems. If these cause damage to pancreatic cells, insulin production may decrease, for instance, resulting in diabetes mellitus. If this happens prematurely, for instance, at the age of 40 years, the rest of the life will be dependent on medication and treatments of diabetes mellitus. Stroke at 60 can paralyze life permanently. Alzheimer's disease can have crippling effect on life as early as mid sixties and early seventies! These health problems can lead to premature death as well and if this happens, the rest of the family, loved ones, all nears and dears will suffer and experience the burden of the tragic event.  When we are young, we work hard and expect good retirement. It's, therefore, very important, to prevent the damages caused by free radicals to avert the unwanted tragic events in life prematurely.   

Endogenous protection mechanism

Three enzymes in the body neutralize extra free radicals and try to keep body in balance. These are:
  1. Superoxide Dismutase (SOD)
  2. Catalase
  3. Glutathion Peroxidase (GPX)
Coenzyme Q10: It is obtained from highly purified fish oil. It is lipid soluble strong antioxidant that is produced by body and stored in the cells. It is involved in energy production in the body, reduces blood pressure and strengthens the heart. Beef, sardine, spinach and peanuts are good sources of Co-Q10.

Using natural antioxidants in food is best way of tackling the free radical damage. However, when natural antioxidant in food intake are not enough, one may need antioxidant supplementation.

Antioxidant rich food

In a USDA research study (June 09, 2004 print edition of the Journal of Agricultural and Food Chemistry, a peer-reviewed publication of the American Chemical Society, the world's largest scientific society) which is considered as most comprehensive analysis of the antioxidant content of commonly consumed foods, so far, artichokes and beans, contain surprisingly high levels of disease-fighting antioxidant compounds. Beside these, cranberries, blueberries, Russet potatoes, pecans and cinnamon are all excellent, although lesser-known, sources of antioxidants, which are thought to fight cancer, heart disease and Alzheimer's. 

Nuts and spices are also good sources of antioxidants but one can't consume large quantities of these edibles. Ground cloves, ground cinnamon and oregano have highest antioxidant levels.
Cranberries, blueberries, and blackberries ranked highest among the fruits studied. Beans, Artichokes and Russet potatoes were tops among the vegetables. Pecans, walnuts and hazelnuts ranked highest in the nut category.

Here is a ranked list of the top 20 fruits, vegetables and nuts:
  1. Small red bean (dried), 1/2 cup
  2. Wild blueberry, 1 cup
  3. Red kidney bean (dried), 1/2 cup[br[
  4. Pinto bean, 1/2 cup
  5. Blueberry (cultivated), 1 cup
  6. Cranberry, 1 cup (whole)
  7. Artichoke (cooked hearts), 1 cup
  8. Blackberry, 1 cup
  9. Prune, 1/2 cup
  10. Raspberry, 1 cup
  11. Strawberry, 1 cup
  12. Red delicious apple, 1
  13. Granny Smith apple, 1
  14. Pecan, 1 ounce
  15. Sweet cherry, 1 cup
  16. Black plum, 1
  17. Russet potato, 1 cooked
  18. Black bean (dried), 1/2 cup
  19. Plum, 1
  20. Gala apple, 1
However, the total antioxidant capacity of the foods does not necessarily reflect their potential health benefit, which depends on how they are absorbed and utilized in the body. It is because of this reason, most people tend to consume antioxidant supplements.

[Sources: American Chemical Society. "Largest USDA Study Of Food Antioxidants Reveals Best Sources." ScienceDaily 17 June 2004. Halvorsen BL, Holte K, Myhrstad MC, Barikmo I, Hvattum E, Remberg SF, Wold AB, Haffner K, Baugerod H, Andersen LF, Moskaug O, Jacobs DR Jr, Blomhoff R. A Systematic Screening of Total Antioxidants in Dietary Plants. Journal of Nutrition 132:461-471, 2002.]

Links to useful articles on other web sites

  • Antioxidants a key to 'long life' (BBC News): Antioxidants might be the key to a long life.  Boosting the body's levels of natural antioxidants could be the key to a long life, according to US scientists. The University of Washington work in Science Express backs the idea that high reactive oxygen molecules, called free-radicals, cause ageing. Free-radicals have been linked with heart disease, cancer and other age-related diseases.
  • Free radicals and antioxidants in health and disease (K. Bagchi and S. Puri; Eastern Mediterranean Health Journal; Volume 4, Issue 2, 1998, Page 350-360). Free radical reactions are expected to produce progressive adverse changes that accumulate with age throughout the body. Such "normal" changes with age are relatively common to all. However, superimposed on this common pattern are patterns influenced by genetics and environmental differences that modulate free radical damage. These are manifested as diseases at certain ages determined by genetic and environmental factors. Cancer and atherosclerosis, two major causes of death, are salient "free radical" diseases. Cancer initiation and promotion is associated with chromosomal defects and oncogene activation. It is possible that endogenous free radical reactions, like those initiated by ionizing radiation, may result in tumour formation... One important line of defence is a system of enzymes, including glutathione peroxidases, superoxide dismutases and catalase, which decrease concentrations of the most harmful oxidants in the tissues. Several essential minerals including selenium, copper, manganese and zinc are necessary for the formation or activity of these enzymes. Hence, if the nutritional supply of these minerals is inadequate, enzymatic defences against free radicals may be impaired... The second line of defence against free radical damage is the presence of antioxidants... Although a wide variety of antioxidants in foods contribute to disease prevention, the bulk of research has focused on three antioxidants which are essential nutrients or precursors of nutrients. These are vitamin E, vitamin C and the carotenoids. Each of these antioxidant nutrients have specific activities and they often work synergistically to enhance the overall antioxidant capability of the body... The balance between the production of free radicals and the antioxidant defences in the body has important health implications. If there are too many free radicals produced and too few antioxidants, a condition of "oxidative stress" develops which may cause chronic damage. As mentioned above, free radicals have been implicated in several health problems. Cancer, atherosclerosis, cerebrovascular accidents, myocardial infarction, senile cataracts, acute respiratory distress syndrome and rheumatoid arthritis are just a few examples. Numerous studies have shown the protective effects of antioxidant nutrients on these health problems. More...

The other side of the story

There are proponents, according to whom only antioxidant rich food is enough for longer, healthier life. Others support consumption of "natural antioxidant supplements". The third school of thought is the one which supports regular consumption of antioxidant supplements. Large number of research studies are available which favor consumption of antioxidants for healthier and longer quality life. However, in order to make an informed and considered decision on whether or not to consume oxidant supplements, one need to look at the other side of the story as well. Here are links to some articles which view the other side of the story and may help in making an informed and considered decision on whether or not to consume antioxidant supplements.


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