sometimes you just have to write something that comes to mind. i could easily share personal life issues that would bore you almost as readily is it bores me, but this blog is about fitness and the news is always coming thru a mile a minute. so let's talk statistics - yes, that boring stuff most of us really don't understand but use when the numbers support our beliefs. btw, i don''t understand stats much either but i've had to make sense of some of the research in order to discuss issues with clients or lecture other fitness professionals for Exercise ETC programs.
let's start with this article in today's NY Times: http://well.blogs.nytimes.com/2012/03/08/shark-cartilage-may-contain-toxin/?ref=health
now, the gist of it is that a particular toxin - BMAA- that's often present in the brains of deceased humans with neurodegenerative diseases such as Lou Gehrig's or Alzheimer's is also present in shark cartilage. shark cartilage is sold and promoted as beneficial for joint degeneration and for cancer prevention, the latter of which has never been proven and has, when touted, received notice from federal authorities. the suggestion of the article, then, is that taking shark cartilage may cause neurodenerative diseases.
now, nothing in the referenced articles support this scare tactic. it is merely a hypothetical. but let me remind you that alzheimers has been around long before shark cartilage has been on the market or that shark has been in the american/western diet; and lou gehrig died many years ago, well before any american ever thought of consuming dessicated shark cartilage for bad knees. furthermore, tho one study referenced the hi rates of certain types of brain diseases in south pacific cultures that eat large amounts of sea food, there are so many other heavy metals in fish that to isolate this one amino acid is to pick at a defenseless protein when other causes can't be found.
let me suggest the following: correlation is not causation. we all learn this in stats and in classes where statistics are prominent features of the science of whatever. you may not have learned it in english 101 or philosophy 203 but even psych 100 or sociology 200 taught this principle. basically correlation means what it says - things are co-related; often one or more elements are found to some degree when one finds other elements of whatever it is one is studying. thus, as in my dissertation topic - leg length discrepancy, athletic injury, and strength imbalances - one might find that a leg length discrepancy is correlated at some statistical level worth considering when someone has an athletic injury but that it is not sufficiently correlated to any strength imbalances (that were studied); and that strength imbalances may be correlated to injury but that length discrepancies are not - making the overall correlation of the three elements so low as to say that it's hardly an issue. and my data indeed found insufficient support for my hypothesis that the three were related. BUT if the study did find them highly correlated, there would still be NO PROOF that discrepancies caused imbalances which then caused injuries. in other words, you may find them all in the same pot but not contributing to the end piece, the injuries themselves.
with that understood, shark cartilage may have an amino acid often found in the brains of people who have certain brain disorders but the amino acid itself may NOT have come from any outside source let alone shark cartilage. it may have come about as a result of some metabolic or physiologic function that went awry in the brain itself or elsewhere in the body and that it accumulated in the brain thereby contributing to the disease itself. BUT since they have yet to pinpoint the actual causes of most neurodegenerative diseases, esp the two mentioned in the article, there's also the chance that it just so happens that the amino acid itself is in the brains of some people as a result of some other more closely-linked biochemical disturbance that actually causes the degeneration.
in other words, don't be scared to use shark cartilage products; just know that they also may not work to reduce joint pain and most likely don't work to prevent or treat cancer.