How are free radicals created within the body?

Hey oem7110, I think this document will answer you question very well.

White blood cells (leukocytes, which aid the immune process) produce free radicals to kill pathogens such as bacteria and viruses.

Oxygen-derived radicals are generated constantly as part of normal aerobic life. They are formed in mitochondria as oxygen is reduced along the electron transport chain. Reactive oxygen species are also formed as necessary intermediates in a variety of enzyme reactions. Examples of situations in which oxygen radicals are overproduced in cells include:

White blood cells such as neutrophils specialize in producing oxygen radicals, which are used in host defense to kill invading pathogens.
Cells exposed to abnormal environments such as hypoxia or hyperoxia generate abundant and often damaging reactive oxygen species. A number of drugs have oxidizing effects on cells and lead to production of oxygen radicals.
Ionizing radiation is well known to generate oxygen radicals within biological systems. Interestingly, the damaging effects of radiation are higher in well oxygenated tissues than in tissues deficient in oxygen.

http://www.vivo.colostate.edu/hbooks/pathphys/misc_topics/radicals.html

"It is therefore not surprising that the more food we eat, the more free radicals we produce."

In order to reduce free radicals, there are 2 life styles as shown below:
1) Don't eat too much during the meal time, but you eat little every 3 hours
2) Don't eat anything except meal time

Does anyone have any suggestions on which case produce less free radical to body?

Furthermore, can I reduce free radicals by hyperventilation? which would reduce carbon dioxide levels and increase oxygen levels. This approach reduces free ionized in the blood. But I don't know on how to work out the details of receiving electrons.

On the other hands, can I reduce free radicals by drinking alkaline water? which supply electron to reduce free radicals.

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>

I would suggest you eat foods that contain antioxidants rather than eating less. Antioxidants neutralize free radicals.

Antioxidant means "against oxidation." Antioxidants work to protect lipids from peroxidation by radicals. Antioxidants are effective because they are willing to give up their own electrons to free radicals. When a free radical gains the electron from an antioxidant, it no longer needs to attack the cell and the chain reaction of oxidation is broken (4). After donating an electron, an antioxidant becomes a free radical by definition. Antioxidants in this state are not harmful because they have the ability to accommodate the change in electrons without becoming reactive. The human body has an elaborate antioxidant defense system. Antioxidants are manufactured within the body and can also be extracted from the food humans eat such as fruits, vegetables, seeds, nuts, meats, and oil. There are two lines of antioxidant defense within the cell. The first line, found in the fat-soluble cellular membrane consists of vitamin E, beta-carotene, and coenzyme Q (10). Of these, vitamin E is considered the most potent chain breaking antioxidant within the membrane of the cell. Inside the cell, water soluble antioxidant scavengers are present. These include vitamin C, glutathione peroxidase, superoxide dismutase (SD), and catalase (4). Only those antioxidants that are commonly supplemented (vitamins A, C, E and the mineral selenium) are addressed in the literature review that follows.


Never heard of that, but I think it's safe to say no, that's not possible.

Great resource: http://www.exrx.net/Nutrition/Antioxidants/Introduction.html

If free radicals are flowing within our body, I would like to know on whether free radicals tend to constrict or dilate blood vessels.

" During exercise, oxygen consumption increases 10 to 20 fold to 35-70 ml/kg/min. In turn, electron escape from the ETC is further enhanced. Thus, when calculated, .6 to 3.5 ml/kg/min of the total oxygen intake during exercise has the ability to form free radicals (4). Electrons appear to escape from the ETS at the ubiqunone-cytochrome c level (14)."

Referring to above statement, I would like to confirm whether increasing oxygen consumption by exercise would produce more or less free radicals within out body.

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>

They don't play a role in vasodialation or vasoconstriction, but they can activate molecules in our bloodstream which can potentially scar tissue the lining within our blood vessels. This ultimately narrows the capillaries that allow for blood-flow. For instance, fatty acids will react with free radicals, which in turn will scar the endothelial tissue...




That's interesting... I never knew this. It sort of bothers me a little.


Because it is not possible to directly measure free radicals in the body, scientists have approached this question by measuring the by-products that result from free radical reactions. If the generation of free radicals exceeds the antioxidant defenses then one would expect to see more of these by-products. These measurements have been performed in athletes under a variety of conditions.

Several interesting concepts have emerged from these types of experimental studies. Regular physical exercise enhances the antioxidant defense system and protects against exercise induced free radical damage. This is an important finding because it shows how smart the body is about adapting to the demands of exercise. These changes occur slowly over time and appear to parallel other adaptations to exercise.

On the other hand, intense exercise in untrained individuals overwhelms defenses resulting in increased free radical damage. Thus, the "weekend warrior" who is predominantly sedentary during the week but engages in vigorous bouts of exercise during the weekend may be doing more harm than good. To this end there are many factors which may determine whether exercise induced free radical damage occurs, including degree of conditioning of the athlete, intensity of exercise, and diet.

Endurance exercise (Stress from working environment) can increase oxygen utilization from 10 to 20 times over the resting state, so Stress play a role in vasodialation, is it correct?

Furthermore, after cells lose electrons and become free radicals, I would like to know on what happen to cells in term of function, oxygen consumption and co2 release.

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>

Post Merge: 9 years ago

I would like to know on what happen to cells if cells lose a pair of electron and become non-radical, would the cells die at this stage?

"Our own bodies know about free radicals, and even use some of them in sending messages around the body or helping the immune system. "

If we have more free radicals, how does it effect on communication within our immune system? Do our immune system perform better with more or less free radicals?

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>

Yes.


No cells... molecules, like Fe or O2. Free radicals don't refer to cells.

I would like to know on what happen to molecule if molecule lose a pair of electron and become non-radical, what would the molecule become at this stage?

"Our own bodies know about free radicals, and even use some of them in sending messages around the body or helping the immune system. "

If we have more free radicals, would it get out of control and attack our immune system / nervous system?

Does anyone have any suggestions?
Thanks, to everyone very much for any suggestions :>

They are reactive and will damage blood vessels. However, like you said, it is best not to think of oxygen radicals as "bad". They are generated in a number of reactions essential to life and, as mentioned above, immune cells generate radicals to kill invading pathogens. There is also a large body evidence indicating that oxygen radicals are involved in intercellular and intracellular signalling. For example, addition of superoxide or hydrogen peroxide to a variety of cultured cells leads to an increased rate of DNA replication and cell proliferation - in other words, these radicals function as mitogens.

Despite their beneficial activities, reactive oxygen species clearly can be toxic to cells. By definition, radicals possess an unpaired electron, which makes them highly reactive and thereby able to damage all macromolecules, including lipids, proteins and nucleic acids.

One of the best known toxic effects of oxygen radicals is damage to cellular membranes (plasma, mitochondrial and endomembrane systems), which is initiated by a process known as lipid peroxidation. A common target for peroxidation is unsaturated fatty acids present in membrane phospholipids. A peroxidation reaction involving a fatty acid is depicted in the figure below.



Reactions involving radicals occur in chain reactions. Note in the figure above that a hydrogen is abstracted from the fatty acid by hydroxyl radical, leaving a carbon-centered radical as part of the fatty acid. That radical then reacts with oxygen to yield the peroxy radical, which can then react with other fatty acids or proteins.

Peroxidation of membrane lipids can have numerous effects, including:

• increased membrane rigidity
• decreased activity of membrane-bound enzymes (e.g. sodium pumps)
• altered activity of membrane receptors.
• altered permeability

In addition to effects on phospholipids, radicals can also directly attack membrane proteins and induce lipid-lipid, lipid-protein and protein-protein crosslinking, all of which obviously have effects on membrane function.

http://www.vivo.colostate.edu/hbooks/pathphys/misc_topics/radicals.html