Tuesday, February 19, 2008
Diet of Worms (apologies to history buffs)
I have mentioned in passing, findings researchers have made about parasites and MS. I even podcasted about it on Charles' MSBPodcast. So here (as Paul Harvey would say) is the Rest of the Story.
There is something known as the hygiene hypothesis. Basically, immune system related illnesses such as allergies are more prevalent in families with fewer children than in large families. The fewer children in a family, the less opportunity a child has of becoming exposed to infectious agents, and that in turn results in a child's immune system remaining "weak" and the child more susceptible to illness or disease. So more siblings lessens your chances of developing allergies.
There has been a steady rise in incidence in the developed world of allergies since the industrial age. And there has also been a steady rise in the incidence of auto-immune diseases, like MS and Inflammatory Bowel Disease.
The hygiene hypothesis has now been expanded to include bacteria and parasites. And the more siblings you have, the greater your chance of exposure to bacteria and parasites. (Can you see where I'm going with this?)
Apparently exposure to bacteria and/or parasites stimulates development of regulatory T cells.
"To use a rough analogy, an unbridled immune system (without regulatory T cells) has the dynamic of a rowdy, unchaperoned beer party. It is likely to overreact to slight or non-existent insults (analogous to allergic disease) and may even attack members of its own party (analogous to autoimmune disease). The role of the T regulatory cells of the immune system is similar to that of the bouncer, keeping the beer party in check." Great explanation from Wikipedia.
A couple of years ago I was reading reports of the link between parasites and MS. And I also read Carl Zimmer's Book, "Parasite Rex", which talked of the rise of auto-immune disease since the Industrial Age. As we have gotten "cleaner" by improving sanitation and hygiene, we have gotten sicker. You've probably heard all the furor about the overuse of antibiotics and antibiotic soaps. As we kill off all bacteria, both good and bad, with these things, we leave ourselves open to attack by adapted bacteria, super-bugs as it were.
There are studies being conducted using parasites to determine how helpful, if at all, they are to folks with MS. The nifty thing about these little parasites is that it looks like only a handful is needed for a beneficial result. And they don't reproduce while they're in you (they seem to want more romantic locales to do that). So once you get over the gross-out factor, it's not such a bad thing.
Links for the studies:Times OnLine