Diseases caused by oxidative stress and their prevention

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OXIDATIVE stress is the name given to the activities of free radicals that lead to damage of cells and other structures in the body. Free radicals are those unstable ions or elements that attach themselves to other cells and structures in order to become balanced. Ordinarily, the human body has the capacity to neutralize the free radicals with antioxidants.  However, when this ability of the body becomes compromised, the free radicals begin to accumulate, causing extensive damage.

Sources of free radicals

  Free radicals, otherwise known as reactive oxygen species (ROS) or reactive nitrogen species (RNS), can either be products of enzymatic reactions or non-enzymatic reactions. Examples of these include the chemical reactions that lead to the generation of ATP (adenosine triphosphate) in the mitochondria of the cells. 

  Also, in the synthesis of prostaglandins and phagocytic activities in the cells, free radicals are released. Conditions where by free radicals are generated are such conditions as excessive exercise, stress, inflammation, infection, immune cell activity, aging, cancer etc. 

  External sources of free radicals are water pollution, air pollution by chemicals and waste gases from motor vehicles and factories, heavy metal poisoning, certain drugs, alcohol, cigarette smoke and radiation.

  Free radicals attack mostly the lipids in the bilayer membranes of cells, the lipoproteins, particularly the low-density lipoproteins (LDLs), proteins (structural and enzymes) and DNA.

Lipid peroxidation

  This is a term that describes the oxidative degradation of lipids (fats) by free radicals as they seek to balance their electrons from the lipids in the cell membranes. This results in extensive damage to the membranes and cells. Polyunsaturated fatty acids are the lipids most often attacked. 

  In what is known as a chain reaction mechanism, ROS such as OH- and HO2 combine with one hydrogen atom to form water and a fatty acid radical. This chain reaction continues and as it does so, different fatty acid radicals and lipid peroxide are produced. 

  This reaction will continue for as long as the free radicals react with the fatty acids and can only be terminated when two free radicals react together. It is the role of antioxidants like Vitamin E to provide the enabling environment for the termination of this chain reaction. If the reaction is allowed to go on, the end results are certain cytotoxic and mutagenic compounds, which can cause cancer and other degenerative diseases.

  Damage to proteins by free radicals can lead to certain structural damage and enzyme deficiency and alteration of enzymatic processes.

  Oxidative damage to DNA can cause mutation which can easily lead to cancer.

If these different mechanisms of attack go on unabated, they will lead to the development of various kinds of degenerative diseases affecting different parts and organs of the body. 

  Ongoing research which started about 50 years ago have shown that oxidative stress is the cause of several chronic degenerative diseases that afflict the human being. These diseases include cardiovascular conditions such as arteriosclerosis, hypertension, heart attack and heart failure. 

  Others are glomerulonephritis, chronic renal failure, Alzheimer’s disease, Parkinson’s disease, stroke, and depression. Also included in the list, are such conditions as rheumatoid arthritis, inflammation, diabetes, aging and cancer. Macular degeneration, cataract and pre-eclampsia are also known to be associated with oxidative stress.

Prevention

  The antioxidant defence system is made up of the vitamin antioxidant system, the enzyme antioxidant system (superoxide dismutase, glutathione peroxidase and catalase), and the antioxidant mineral system. The major minerals, which act as co-factors in the enzymatic reactions are zinc, copper, magnesium, selenium and iron. 

  Apart from the 3 enzymes which are produced in the body, the other components of the antioxidant defence system are found in the leafy green vegetables, fruits, grains, nuts and animal products, such as red and lean meat, organ meat, dairy, sea foods and fish (tuna, salmon, sardines etc.) Incorporating these foods in our diet regularly will no doubt help to prevent diseases caused by oxidative stress.

A word on water

  As you very well know, water is the most abundant nutrient in the body. Availability of water in sufficient amount is an immune booster and such can speed up the circulation and elimination of waste products. Not only that, some minerals are a common finding in our drinking water. For example, zinc, magnesium and copper which are part of the mineral antioxidants are present in the artesian natural mineral water. Drinking of such water will be a sure way of preventing those chronic diseases.



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