Sunday, January 13, 2008

Mario's Antioxidant Needs

To illustrate the antioxidant needs of a person, let's examine how Mario(a fictitious character) spends his week. Only the antioxidant requirements arising from his physical activities will be illustrated. Other antioxidant needs caused by other free radical generators like smoking and toxins will be omitted.

Mario's antioxidant levels on a weekday

The alarm clock rings and Mario wakes up. It's a Monday and it's time to go to work. He stretches and pulls himself up and starts his weekday..

Every time he uses his muscles, he spends energy. He gets this energy from ATP(Adenosine Triphosphate) produced mainly by the mitochondria of his cells(aerobic metabolism or respiration). The mitochondria processes food and oxygen to produce ATP and free radicals are natural by-products of this process. If antioxidants were not around to neutralize these free radicals escaping the ATP production, substances within the cell including the mitochondria and DNA could be damaged because of the free radical chain reaction. Free radicals are highly reactive, they steal electrons from nearby molecules which starts a chain reaction. About 10.000 oxidative hits to the DNA of each of his cells occur each day. When the DNA becomes damaged, mutations can occur which can possibly lead to cancer. That's how important antioxidants are inside Mario's cells.

Mario feels sluggish because of his weekend sports activities. His body aches especially the muscles involved in chasing and hitting the tennis ball with his racket.

He rides the bus in going to work, walks a block from the bus stop to his office building and takes the elevator to reach his office located at the 5th floor. There he spends most of his time behind his desk. That's his routine from Monday to Friday.

The amount of ATP's that his cells generate depends on his activities. The more he exerts physical effort, the more ATP is produced. The more ATP is produced, the free radicals generated also rises proportionately. Mario's body adjusts it's antioxidant levels to match the physical activities that it is used to.

Mario's antioxidant levels on weekends

Juan wakes up earlier than usual. It's a Saturday and it's his time of the week to play his favorite sport.

Upon reaching the tennis court, he does some stretching and light jogging to warm him up. He spends energy using ATP from his cells.

Replenishing spent ATP from his cells does not always require oxygen. The phosphagen and glycogen-lactic acid system are anaerobic metabolisms which does not require oxygen to manufacture ATP. We'll only focus on aerobic metabolism since this is the system which uses oxygen and hence free radicals.

The game begins and Mario's top spins are performing perfectly. His backhand top spins require more mastery though. He chases the ball and hits it back with his racket to the opposite court. Mario is having fun! All these require his muscles to exert effort and spend ATP. A few minutes later, he begins to breathe heavily.

Aerobic metabolism as the name suggests require oxygen to manufacture energy. The more ATP to be replenished, the more oxygen is needed to produce it. That's why Mario breathes heavily to let in more oxygen. The blood vessels of his muscles dilate the the blood vessels of his organs and other parts of his body constrict to allow more blood which carry oxygen to flow to his muscle cells. Muscle performance is the priority in Mario's present activity.

Several more minutes later, Mario begins to pant. More oxygen is required!

About 2% of the oxygen used in aerobic metabolism can produce free radicals. Therefore free radical generation arising from aerobic metabolism rises proportionately with ATP production. Mario's level of antioxidant defenses are used to the free radical levels of his weekday activities. This tennis game is far too strenuous and too much energy spending than what his body is used to during weekdays. His antioxidant levels can adjust for some fluctuations of antioxidant requirements but not this much. Certainly oxidative damage can occur in his muscle cells before it can be neutralized by antioxidants. Thanks to what his wife prepared him for breakfast which included some fruits and green tea with lemon - they contain antioxidants which can help Mario's natural antioxidant defenses, the damage caused by free radicals in his muscle cells was not too much.

Later, Mario begins to feel some soreness in his body. He doesn't mind it because he is having fun.

This soreness can partly be due to oxidative damage but our cells have repair enzymes to handle that. Some can be repaired and some cannot. Those that cannot be repaired can accumulate over the years make those cells perform less than normal.

The next day, the soreness of Mario's body becomes more pronounced and he takes a rest.

Mario's weekday activities is not a good practice

As you can see, Mario's sedentary weekday activities is a big contrast to his sport activity on a saturday. His body's antioxidant levels cannot adjust to the sudden change. His body can adapt to his sport activity during a saturday if he exercises on some other days of the week. It is also important to do it gradually so that his body can adapt a smooth antioxidant level adjustment.

Mario may not notice the bad effects it has on his muscle cells but since oxidative damage can accumulate through the years, the manifestations may be noticeable later in his life. An example of how oxidative damage can accumulate over the years are the wrinkles on the skin. If you have noticed, people who are often exposed to the ultraviolet rays of the sun have more wrinkles than people who are less exposed to it. That's because the sun's rays can cause oxidative damage to the skin and overtime these damages becomes more pronounced and visible.

Researchers have estimated that each of our cell suffers 10,000 DNA lesions from oxidative stress. On a saturday, Mario's DNA on his muscle cells can suffer more than that.

Protect yourself from oxidative damage with extra antioxidants

To have our natural antioxidant defenses perform well, we need to have a regular activity. That would be hard to accomplish since sudden changes of activity cannot be avoided. Running to the office so as not to be late for example. We are also exposed to different free radical generators like smoking, automobile exhaust emissions, sunlight and toxins we ingest from food. Even our own body's immune system produces free radicals to kill bacteria and viruses.

A good way to protect ourselves from oxidative damage thereby preventing disease is to have extra antioxidants in our body. One good source are fruits and vegetables. Five servings each day are recommended by the Cancer Society. If not possible there are many antioxidant supplements available in the market.

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