Posted by Larry Hoover on January 5, 2003, at 10:45:32
In reply to Re: Fish oil--for Larry Hoover and » Larry Hoover, posted by viridis on January 5, 2003, at 3:07:03
> Hi Larry,
>
> I'm not a chemist or toxicologist, but my understanding was that although inorganic forms of mercury aren't very lipid soluble, some organic forms such as methylmercury (which I think is of greatest concern) are. Is it just that, once in an organism, the attraction to some of the amino acids in proteins is strong enough to keep the organic forms out of the fats as well?In living organisms, the partitioning is a little different than in post-mortem ones being processed for by-products.
You're quite correct in asserting that mercury is lipid soluble. That permits mercury free access to any cell in the body, as it can diffuse across the lipid membrane. I assume that living organisms have some mercury in their adipose (fat storage) tissue, but that would probably be a transient phenomenon, reflecting trends in exposure over time. The mercury would just keep moving around, until it found substances which bind it chemically. Those substances tend to be proteins, which unfortunately include some very key enzymes/co-enzymes (all with sulphur-based active sites), e.g. S-adenosyl methionine (SAMe), super-oxide dismutase (SOD), and antioxidants like glutathione (actually a short peptide). Mercury will also bind (essentially permanently) to selenium, which affects another host of key enzyme systems which depend on selenium. One of the best ways to mitigate mercury exposure is to take selenium supplements (200-400 mcg (micrograms!) per day, maximum).
It would be hard to measure in absolute terms, but mercury exposure should definitely be considered to be one of the environmental stressors predisposing people to symptoms of depression, and quite likely also contributing to factors influencing chronic fatique and fibromyalgia.
> I'm just curious, and I certainly don't want to turn this into the fear of fish oil forum. It seems quite clear that mercury in fish oil supplements isn't a big concern. I'm really asking a more general question about mercury in the environment because I'm interested in these problems.
>
> Thanks in advance,
>
> ViridisThe chemical processing that permits the recovery of fish oil degrades the cell structure to such an extent that virtually all mercury present in the tissue will be "mopped up" by proteins in the "fish soup", something like a sponge for heavy metals. Fish oil contains no protein, and thus, no metals (to the limit of detection, which stands at something like 0.6 parts per billion).
You're welcome.
Lar
poster:Larry Hoover
thread:134049
URL: http://www.dr-bob.org/babble/20021230/msgs/134599.html