« 7 Million | Main | Elite Athletic Training and Disease »

Antioxidants in Equilibrium

July 17, 2006 09:28 AM

A fascinating and informative exchange of comments between Neal W and UTHSCSAML.

It is a familiar one to an economist in mathematical terms, though the problem is very different from solving for a market equilibrium.

What is involved is really a simultaneous equation system and its solution. Oxidative challenge (ROS) upregulates antioxidant production (SOD, catalase, etc.). But it also increases the rate at which antioxidants are depleted. So, the amount of the antioxidants found in the tissues is the result of an equilibrium between these two processes.

It is similar to my model of the force level of the armed forces (see the earlier post by searching the archives), which responds to the accession rate and loss rate. Or, think of the bath tub analogy: the faucet lets water in, the drain lets it out. The amount of water in the tub depends on the flow rates of the inlet and the outlet. Since they are stochastic flows, it has to be the case that the outlet has a larger capacity than the inlet or the tub eventually will over flow.

The experiments and the comparisons across species are looking at the level of water in the tub and trying to make inferences about the flows. They really need to model flows on both sides, antioxidant production, chronic and acute responses to ROS challenge, and antioxidant depletion and uptake. One thing they should see is that the sum of depletion and re-uptake of antioxidants must, on average, exceed the rate of production. Otherwise, antioxidants to rise to toxic levels.

For my own part, I do try to alter the ROS challenges I face. First, to promote an acute response to retain the ability to respond when a real challenge comes along. This is the hormesis theme again. Sprinting is one of the ways I do this. And the high pace of my work out/play sessions produces a bit of an acute challenge to my muscles, metabolism, and my ROS defenses. All these are acute and intermittent, not chronic or patterned in a routine way.

I do take antioxidants and have plenty of them in my diet as well. Here the issue is not only the level but taking care not to overload pathways with one or two sources of antioxidants. You must avoid doing this because you will crowd other antioxidants out of the pathway. That seems to be an issue, for example, with beta carotene. There are many carotenes and taking a lot of beta type can crowd out the others.

I think I carry a low ROS load because of my brief, intermittent and unpatterned activities. I make little use of the aerobic pathway directly in my anaerobic work outs and play. Of course, I use it later in post-exercise repiration, but at a very low ROS load (no peak) relative to the amount of work I did. I think, but have not measured, that I have much uncoupling proteins in my muscle and brown adipose tissue. Uncoupling the respiratory chain dramatically drops the ROS load even while you are burning huge amounts of energy. Intense activity seems to stimulate UCP expression and my frequent exposure to cold and shivering likely keeps my brown adipose tissue (BAT) intact and active. Moreover, it is well protected from free radical damage by my antioxidant intake.

I give off waves of heat through high BMR, BAT, and UCP. Any girl who gets close to me begins to sweat.

· Evolutionary Fitness

Comments

"I give off waves of heat through high BMR, BAT, and UCP. Any girl who gets close to me begins to sweat."

My new favorite pick-up line for the club.

Ok, seriously, your hit count is amazing and is a testament to the incredible knowledge you display regarding so many subjects. You da man, Art!

Posted by: oboffill [TypeKey Profile Page] at July 18, 2006 10:17 PM

Art,

So is are the levels of SOD, catalase, and GSH-Px higher in the IF fed rats because IF results in less oxidative challange and thus less antioxidant depletion? I wouldn't think that the reason there was an increase in SOD, catalase, ect. was because antioxidant production was upregulated by an increase in oxidative challenge.

I just want to know if I should be looking for higher levels of these things or lower as a good thing in the study you referenced.

Posted by: Neal W. [TypeKey Profile Page] at July 17, 2006 9:29 PM

Post a comment

Thanks for signing in, . Now you can comment. (sign out)

(If you haven't left a comment here before, you may need to be approved by the site owner before your comment will appear. Until then, it won't appear on the entry. Thanks for waiting.)


Remember me?