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Free Radicals in the Human Body

01/23/2009 5:27 PM

My intuition tells me that, if free radicals are produced by respiration, digestion, or other means, they would be immediately neutralized. If they floated around inside the body looking for an opportunity to do damage, the chances of an antioxidant finding them would be about the same as two satellites in orbit colliding. Has anyone ever detected a free radical in the human body and has anyone ever detected an antioxidant neutralizing a free radical?

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#1

Re: Free radicals in the human body

01/23/2009 8:54 PM

I have always believed that is something cosmetic and mineral water companies invented to scam their customers.

Same as you, I see a free radical as doing an immediate damage as soon as it is formed and then disappearing. If you have to eat peaches or drink ginkgo biloba to neutralize them, why those people who just eat meat with potatoes are still alive?

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#6
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Re: Free radicals in the human body

01/24/2009 3:47 AM

Spot on (GA to you)... the body has evolved to deal with all the great variety of stuff we ingest with little artificial intervention. Clean water and basic hygeine are fundamental requirements. The rest is marketing hype.
I shall go eate some grass and puke up to rid myself of toxins and free any falsely imprisoned radicals.
Del

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#10
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Re: Free radicals in the human body

01/24/2009 8:40 AM

ROFL... the grass eating, another doggy conspiracy..

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#12
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Re: Free radicals in the human body

01/24/2009 8:50 AM

Agree, er, except the puking part.

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#2

Re: Free radicals in the human body

01/23/2009 10:10 PM

That intuition is more or less correct. There are numerous internal mechanisms for neutralizing free radicals and for repairing damage done by them. These quick repairs are done all the time; the real issue with oxidative stress is in special circumstances.

Instead of single molecules wandering in the interstellar space of your body, think about concentrations of free radicals which are intensely elevated for one reason or another in one part of your body. For example, in spinal cord injury as in the rat study here. (warning: don't read for light entertainment..) . When the internal mechanisms and nutrient status are not enough to neutralize and repair oxidative damage, then it can be irreparable. Or, what the hell, you get run down, and get the flu...

As for the antioxidant marketing (we all hate the marketing!) you don't have to chew quinoa or burdock roots.. there are a hell of a lot of antioxidant properties in foods, so if you want, pick your favourites and enjoy (chocolate, red wine, etc etc) with the added excuse "IT IS GOOD FOR ME" I bet you can name any food we can find rational excuses to indulge and feel good about it

As to the question about research in the human body, the process is the same in animals and you will find most research in animal rather than human bodies. A PubMed search for "free radical antioxidant" lists 101932 responses: "free radical antioxidant in vivo" lists 9748. "free radical antioxidant in vivo human" lists 3570 and there are several studies on the first page that describe methods of measuring oxidative stress levels in a clinical setting, if you want to do this research. http://www.ncbi.nlm.nih.gov/sites/entrez

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#3
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Re: Free radicals in the human body

01/23/2009 11:44 PM

Hi artsmith

A GA vote for you. (I am not an expert but I live to that.)

Thanks for the link to pubmed - now I can ask my stupid questions at leisure. All I need now is to understand Greek.

Do Pubmed have a GA system and do Withdrawn imply off-topic?

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#7
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Re: Free radicals in the human body

01/24/2009 7:48 AM

I'd be happy to help with the Greek anytime. PM me or post and I'll do my best.

The articles on PubMed are all peer-reviewed, for what that's worth. Whether they are GA's or not, the better abstracts lay out the methods and statistical basis so you can see and judge, but it's better if you can read the whole article. As for 'Withdrawn' that means a decision was made not to publish, either by the publisher or the author or maybe even the corporate sponsor. there are things they don't want you to know!

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#4
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Re: Free radicals in the human body

01/24/2009 12:47 AM

Artsmith: Thank you for the comments about free radicals. I haven't thought about clusters of free radicals. Those should show up on nuclear magnetic images. I suspect the free radicals might be doing their damage in a very short time at the sites where they are created. It may be that no one has detected a free radical when it is formed, but the damage they do remains.

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#8
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Re: Free radicals in the human body

01/24/2009 8:19 AM

The role of the free radicals (Greek note: often abbreviated ROS or 'reactive oxygen species') in damage processes in vivo has been established by the animal studies, where they don't have to use imaging, they take tissue samples (ok they kill em and cut em up) and examine directly using chemical test and other histology (= study of tissues) methods. Same things can be seen in cell culture studies under a microscope, using various stains to show the biochemical status in question. this is just generalizing, you will find many many specific methods used depending on the exact molecular interactions being studied.

In vivo humans, the most likely methods to measure oxidative status would be to take samples of bodily fluids and do chemical tests. In fact, there's a simple and safe way to check your oxidative stress status at home: by taking 500-1000 mg of vitamin C. All the C that isn't used up is peed out: if you don't need it (oxidative status good) it will turn your pee bright yellow. When you have the flu or some other big oxidative stressor, you can consume a lot of C without excreting any of it.

You're right, it's the damage left behind that can be picked up in imaging, rather than the radicals themselves. People worry about the undetected damages on a DNA cellular level that eventually (might) lead to cancer. Hence much marketing is focused on the less detectable of our fears...

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#9
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Re: Free radicals in the human body

01/24/2009 8:33 AM

although actually you are right, MRI for example could show oxidative processes as they are happening, as long as the activity is intense enough to be within resolution of the device..

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#14
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Re: Free radicals in the human body

01/24/2009 11:35 PM

Hello one and all,

Some free radicals in the body are generated by leaky mitochondria, the power houses of cells. When a person goes on a low calorie diet, the mitochondria tighten up and do not let the free radicals escape. They are part of the biochemistry of converting sugar into ATP, the energy carrying molecule of the body.

Other free radicals are created by some of the white blood cells. These free radicals are used to kill bacteria. This type of free radical is often a two oxygen molecule that has an extra electron.

In both cases, the body tends to have other molecules in the area to quench the unpaired electrons of the free radical.

I doubt that an MRI would have the resolution to detect any single free radical, nor the quenching of the free electrons involved by any of the antioxidants in the body.

The resolution of MRI would need to be at molecular level if individual free radical bearing molecules were to be detectable.

With regard to the other questions about antioxidants and supplements, when in doubt, eat your vegetables. They have mitochondria too, and many have high levels of antioxidants during the sunny period, when they need the antioxidants to quench all the stray free radicals that excape the mitochondria during photosynthesis.

Remember, the leading cause of death is birth.

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#15
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Re: Free radicals in the human body

01/26/2009 7:38 AM

It seems that eating large quantities of vitamin C gives me dry skin. Am I imagining this?

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#16
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Re: Free radicals in the human body

01/26/2009 11:51 AM

It's nothing I've ever noticed or heard of. The amounts I have used, usually a thousand at a time every few hours with the flu, probably never exceeded 6000 mg in a day. If the large amount is more than that, I don't know. The only connection between Vit C and skin that jumps to mind is scurvy: caused by extreme deficiency. Maybe imagined?

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#11
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Re: Free radicals in the human body

01/24/2009 8:47 AM

I always used thet excuse to enjoy a fine Cabernet or Merlot. I leave the chocolate for the Wifey.

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#13
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Re: Free radicals in the human body

01/24/2009 9:20 AM

The statisticians came up with one that they run every year now around Valentines: they say that Canadian women prefer chocolate to sex Another devious marketing ploy, no doubt!

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#5

Re: Free radicals in the human body

01/24/2009 1:34 AM

The human body is very mysterious.

Apparently formaldehyde, which in most cases is toxic, is generated with the aid of coenzymes, to act as a methyl group donor to transform dUMP into dTMP which is used in DNA production and cell division.

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