HEALTH TIPS

Healthy Lifestyle Tips

• Every one is talking about antioxidants ! A major pharmaceutical company runs full-page ads in newsmagazines pointing out the dangers of oxidative stress while mentioning that three of their multivitamins products can protect you from excess oxidation. Sales of vitamins have been increasing by 20 to 30 percent per year, and much of the growth can be credited to antioxidant formulas. Animal studies and several large controlled human trials point to the wisdom of taking antioxidant supplements, especially vitamin E to help prevent heart disease and cancer.

  It is useful to know what oxidative stress is and which compounds normally found in our bodies protect us from the damaging effects of oxygen. This demonstrate how antioxidants can be protective, and it can also help you decide what might be the most important antioxidant for you to take. 

  This chapter explains antioxidant in the context of a regimen for good health.

  OXYGEN RADICALS

  Only some microorganisms (and plants), known as anaerobes, can live without oxygen; most, including humans, need oxygen. Anaerobes make energy by breaking down preformed carbohydrates and proteins, but energy-wise this process is inefficient. Most microorganisms and all animals (including humans) use oxygen to "burn" or oxidize foods into carbon dioxide and water. A great deal of energy is produced as a result of this process. Metabolizing one molecule of glucose with oxygen produces about four times as much energy as could produced if the same molecule were to be metabolized without oxygen. In our bodies, carbon from food is oxidized to carbon dioxide. Oxygen superoxide grabs electrons from a neighboring source and combines with hydrogen to form water. The reduction of oxygen is accomplished in special structures inside body cells called mitochondria. Carbon dioxide that results from this process is eliminated in our breath, urine, and sweat. Plants use the carbon dioxide we produce to make oxygen. This is a very nice ecosystem, and one we need to be careful not to disrupt.

  But the system isn't perfect. Did you ever notice how rubber or plastic becomes brittle and cracks after some time has passed? This happens when these materials react with oxygen in the air to produce a modified plastic or rubber that is not as soft and flexible as the original. We live in an environment filled with oxygen, and this is exactly what happens to our bodies as we age. Our skin loses flexibility and starts to wrinkle; our organs don't work as well; our blood vessels get clogged with plaque, putting us at risk at a heart attack or stroke; and we are at a higher risk for cancer. Oxygen is not the only reason that  our bodies deteriorate, but it is part of the picture. 

  Oxygen damage body tissues after long periods of exposure  because tiny amounts of chemically reactive oxygen  are produced in the everyday reduction of oxygen in  the mitochondria. This reaction sometimes occur in  other parts of our bodies as well. Reactive oxygen  molecules that cause the problems described above  are called free radicals. They will reach out to whatever  is close by and attach to it. Let's say, for example,  that the free radical combines with a lipid molecule  in a kidney cell membrane. The lipid molecule is now  a reactive radical itself and can react with another  oxygen molecule to form a lipid peroxide radical.  Meanwhile, a neighboring radical reacts with oxygen  in the same process. This can continue until the kidney  cell is permanently damaged. In theory, a single radical  could destroy us with this chain reaction!
  

  Actually, there are many different kinds of oxygen radicals. The most important are superoxides, hydroxy radicals, and perhydroxy radicals. These are extremely reactive and will combine immediately with anything nearby. There is another reactive from of oxygen as well, called singlet oxygen.
  

  Oxidative injury is implicated in a long list of disease. Following are some of the more important examples. 
  

  DISEASES RELATED TO OXYGEN RADICALS
  

  Hardening of the Arteries (Atherosclerosis)
  

  We have "good cholesterol" and "bad cholesterol" in our bodies. Good cholesterol is attached to lipids called HDL (high-density lipoproteins). Bad cholesterol is attached to LDL (low-density lipoproteins). One reason that the LDL cholesterol is bad is that it can from plaques in our arteries. When a plaque cracks or is otherwise activated, a blood clot can from that blocks blood flow through the artery. If the clot is in an artery that supplies heart muscle, the blood supply to part of the heart is blocked. This lead to chest pain or a heart attack. If the clogged arteries carries blood to the brain, a stroke or TIA can develop. If the clogged artery is in the leg, pain develops on exercise, and in very severe cases leg amputation may be needed.

  In the past decade it has become apparent that the free 0 radical oxidation of LDL is important to the process of plaque formation. This is one of the most important findings for heart disease and stroke prevention to date and provides many ways for people to help decrease their risk of heart disease.

  Unmodified LDL does not begin the process of plaque formation. It can be inappropriately oxidized in the artery wall, though. Once LDL reacts with an oxygen radical, it is seen as a foreign substance by body defense systems and is attacked by protective cells called macrophages. Unfortunately, the process can be destructive, and the oxidized LDL sets up an inflammation in the outer layer of the artery that leads to a "fatty streak" and, later, a plaque deposit. Both can start the process of blood clotting. Chemicals, including antioxidant vitamins, that neutralize free radicals can help block plaque formation and may reduce the risk of heart attack and stroke.
  

  The Complications of Diabetes
  

  High glucose levels in blood and tissues that result from diabetes lead to increased LDL oxidation. Diabetes have an increased incidence of coronary and vascular diseases, and antioxidants have the potential of decreasing some of the LDL oxidation associated with diabetes.

  Cancer

  Exposing DNA in our cell nuclei to free radicals may result in DNA strand breaks and mutations, leading to cancer. Chronic inflammation and injury generate free radicals as part of the process, which helps explain why these conditions increase the risk for the development of cancers. For example, the hepatitis viruses often cause a chronic liver infection that sharply increases the risk of liver cancer. The inflammation caused by inhaled asbestos results in high risk of lung cancer. Antioxidants have the potential to decrease cancer risks by neutralizing the free radicals causing damage. 

  Inflammation

  Body cells whose job is to engulf and destroy bacteria and damaged tissue particles accomplish this by producing short bursts of hydrogen peroxide and superoxide. For reasons that are not well understood, the process can get out of hand and these chemicals set off reactions like the one outlined earlier, leading to tissue injury. The reaction products of free radicals are detected in synovial fluid. The chain reaction sequence described earlier is probably important is spreading the inflammation and damage. Arthritis is one example of this situation, and antioxidants have the potential to help prevent inflammation.