spurious correlations (was: Re: Guernsey Milk)

[Guest guest]

>

> This is an article about Guernsey milk and casein.

>

> http://news.bbc.co.uk/hi/english/health/newsid_1268000/1268481.stm

>

I wouldn't take that very seriously for several reasons:

1. Multiple comparisons: When you are looking at studies of nations

or people you can try and to find correlations of literally hundreds

or thousands of differant things (for example, every vitamin, every

mineral, differant anti-oxidants, fat, protein, carbs, differant

types of fat like omega-3 and omega-6 etc...) to heart disease. By

the time your at the level of comparing two differant milk proteins

you could be comparing tens of thousands of differant things. In

science relationships are considered to be significant when you there

is a 5% or smaller probability of that being coincidence. That means

that if you think of 1000 differant things to test, then 50 of them

would be significant through pure random chance. This means that we

still have at least 49 other kooky theories left

2. Biological plausibility: The theory behind A1 casein is that it

damages the arteries, causing atherosclerosis. But proteins are

broken down amino acids when digested; otherwise they cause

indegestion. So really the theory would have to be that A1 casein in

combination with leaky gut syndrome (undigested food entering the

bloodstream) causes heart disease. Is the problem that you're

suffering drinking Jersey milk, or that you have Leaky Gut Syndrome?

3. More biological plausibility: most heart attacks are caused by

arterial plaque that blocks less than half of the artery. Heart

attacks do not occur because of arteries being blocked, but because

arterial plaque becomes inflammed and weak, and eventually ruptures,

which in turn causes the heart attack. You can hypothesize that

undigested A1 casein is sharp and prickly and damages the arteries,

leading to atherosclerosis, but atherosclerosis is a universal

process found in all people, regardless of whether they drink milk or

not. The problem is not atherosclerosis, but plaque becoming

inflammed, weak and loaded with clotting substances. How does A1

casein cause that?

IMO, the theory is pretty kooky and lacks credible evidence - the

cholesterol theory looks good by comparison, which tells you how

crazy it is!

Amusingly, I was reading a vegan message board last night (and

Cohen's NOTMILK group), and this thread is very common: someone

comes across an article or study that challenges their faith, people

rally around and posts dogma from PCRM (a PETA funded animal rights

group that poses as a group of physicians) until everyone feels

better. I suppose its probably just human nature, and the only

differance between them and us is that we don't find many studies or

articles that do a credibly challenge us!

P.S. references for any of this upon request (I don't feel like

digging them up, but it would only be a small effort)