Naked Science Forum

Life Sciences => Cells, Microbes & Viruses => Topic started by: Bob Calder on 14/12/2010 09:30:04

Title: Where can toxins accumulate in the body?
Post by: Bob Calder on 14/12/2010 09:30:04
Bob Calder  asked the Naked Scientists:
   
Chris,

SciFri had an interview with a climatologist who described probable errors in thinking allowing US lawmakers to be climate change deniers. The argument included people thinking "greenhouse" has a hole (ozone hole) in the roof that allows heat to escape so we can't have warming.

I was wondering if there were similar problems when people think about cells and the burdens they can and can't carry, both of nutrition and poison.

Example of statement: Feeding salmon in a farm a diet of fish meal results in salmon that are nutritionally deficient when compared to wild salmon.

I'm thinking the error has something to do with thinking of the cell as a sack that can hold anything, while in reality, it is constrained. But where do toxins reside if nutrition isn't allowed to have a "super abundance" condition? Are different toxins held in different ways?

When I was in Biology class over 40 years ago, things got into and out of the cell by means of hand-waving and throat clearing.

Bob Calder

What do you think?
Title: Where can toxins accumulate in the body?
Post by: CliffordK on 14/12/2010 10:23:16
The argument included people thinking "greenhouse" has a hole (ozone hole) in the roof that allows heat to escape so we can't have warming.

I like that...
Did they consider WHERE the Ozone hole is, and WHEN it occurs...  I.E.  It occurs primarily mid-winter over the poles where it is essentially dark 24 hrs a day and very very cold!!!  (maybe the ozone hole let the heat out from Antarctica). 

But, one must keep in mind that the Earth does radiate a lot of heat into space.

I'm thinking the error has something to do with thinking of the cell as a sack that can hold anything, while in reality, it is constrained. But where do toxins reside if nutrition isn't allowed to have a "super abundance" condition? Are different toxins held in different ways?

If I remember right, there are Water Soluble Toxins and Fat Soluble Toxins (and drugs).

The Fat soluble toxins tend to accumulate in your fat cells...  that allows them to be essentially hidden from the organism.  But, they also can stay in the organism for a very long time.  The fat soluble drugs/toxins tend to be metabolized through the liver.

The Water soluble toxins tend to stay in the blood & cytoplasm.  Thus, the acute load of the toxins may be higher, but they are quicker to be eliminated from the body, primarily through either metabolism in the liver, or excretion through the kidneys.  The effect may also depend on whether they tend to stay in the blood, or enter into the cells.

There are also toxins that mimic natural elements in the body, and might be incorporated into structures such as bone, and then would endure almost indefinitely.  Certain radioactive isotopes of light elements can be incorporated into structures just like their non-radioactive counterparts, but can cause damage if they undergo radioactive decay.

Lead will mimic Iron, and will replace the Iron in the blood, but is less effective at carrying oxygen.  Its turnover rate is slow, perhaps only as the red blood cells die and are recycled.

Carbon Monoxide will bind to oxygen receptors on Hemoglobin in the blood, and while it is released through respiration, it is released slowly, and while bound to hemoglobin, it displaces the oxygen carrying capacity of your blood.
Title: Where can toxins accumulate in the body?
Post by: bob_calder on 14/12/2010 15:16:15
As to where and when the ozone hole appears, we are talking about errors in thinking, so no they don't consider. But the big error is in extending the metaphor of "greenhouse" to include the climate in a too-literal way.

Thanks for the overview of possible toxin locations and water versus fat soluble lipids for storage. I suppose that for nutrient storage it depends on needs to begin with, then speed of metabolism to set up some kind of framework for relative abundance of things with different properties - such as lipids.

So how *should* one go about explaining that unless it carries a burden of toxins, a muscle carries pretty much the same nutrition if the body is nourished by grains as by eating little fishes?
Title: Where can toxins accumulate in the body?
Post by: CliffordK on 14/12/2010 16:04:04
Oh, sorry,
I missed the salmon thing... go stuck with toxins.

I don't know if farm fed salmon/fish is different than wild. 

We derive the following from food we eat.
Calories
Proteins (note that there are 8 "essential amino acids").
A few vitamins.
Is omega-3-fatty acid healthy?

The fish should be similar independent of the source.

I am seeing some negatives for farming including PCB accumulation, especially in fish fat.. with the farmed fish being fatter, and thus carrying more PCBs. 

Caged animals (fish, as well as deer&elk) carry a risk of developing diseases, and then transmitting them into to the native population.

Hatchery style farming of Salmon can prevent all the dead carcases from going to waste, although by the time salmon are ready for spawning, they can be in pretty bad shape.

http://en.wikipedia.org/wiki/Aquaculture_of_salmon
http://www.healthcastle.com/farmed-salmon.shtml

Title: Where can toxins accumulate in the body?
Post by: SteveFish on 14/12/2010 17:42:16
Bob:

I am having a little trouble understanding what it is that you would like to know about cells. There is very little hand waving regarding how substances get in and out of cells anymore. Ask a specific question.

Steve
Title: Where can toxins accumulate in the body?
Post by: bob_calder on 15/12/2010 15:04:36
Steve,

My original question asks for a specific strategy for helping people understand that although foods can carry toxins, the method of growth, ie being fed "natural" foods versus fish meal doesn't affect the nutritional value of fish (in this case salmon) when we eat them. The question arose in my mind during a conversation about farm raised salmon versus wild salmon. It is my understanding that farm raised salmon have less mercury but more PCBs from my limited reading. But setting aside contamination concerns, the discussion was about nutrition. The difference in price between wild and farmed at the shop is approximately 100% in my case.
Title: Where can toxins accumulate in the body?
Post by: SteveFish on 15/12/2010 20:56:10
Thanks Bob, that is simple enough for my confused mind. I don't think anybody could say that the farmed salmon are getting a bad diet in terms of nutrition. After all, the farmers won't make as much money if the fish don't grow well. I would say that the biggest difference between farmed and wild salmon is in the quality of the fish for us. I don't buy farmed fish because they don't taste good, not because they aren't nutritious. This is sort of like the difference between a fresh picked garden tomato, and one in the grocery store, but also of other fruits, eggs, and home grown meat for example.

I guess the only fact I would like to know about farmed salmon, from a human nutritional point of view, is if they provide as much omega 3 fats per unit weight as wild fish. These fats are an essential nutrient for humans. That is, they are necessary for life and our cells are unable to manufacture them. Steve
Title: Where can toxins accumulate in the body?
Post by: bob_calder on 16/12/2010 00:12:56
There is a report on PCBs that says you want to get as much skin and fat off a salmon as you can.
I don't know about the reliability of this source. Only two scientists on staff out of what looks like twenty.
http://www.ewg.org/reports/farmedpcbs
I found a second one sponsored by the state of Oregon and funded by fish industry folks that seemed to say the same thing. Who knows what has happened in the meantime. Since the PCBs arrive in feed, it should be possible to have improved things in the intervening years.