Thursday, November 01, 2007

Lipoprotein(a) and oxidised cholesterol

Lipoprotein(a) is a subgroup of LDL cholesterol which has had an extra protein added to it. This extra protein is sticky, particularly to the lysine and proline residues of collagen which get exposed in damaged arterial walls. Like LDL cholesterol, it is a method of applying a sticking plaster to damaged vascular endothelium. If you have lots of damage to your arteries you would expect your liver to make lots of lipoprotein(a). It's not stupid. Lipoprotein(a) is especially needed if you have defective LDL receptors, so in familial hypercholesterolaemia you would expect lipoprotein(a) to be high. That's what you find. Using a second choice repair system is likely to be associated with a poor repair and so with heart disease. It is. Oddly enough, if you live long enough this extra repair system becomes rather important and centenarians have rather high levels of lipoprotein(a). So it can't be all bad.

Anyway, a quick google or pubmed search on lipoprotein(a) will tell you that that it is a risk factor for heart disease (now there's a surprise) and that your blood level is genetically determined, so there's nowt you can do about an elevated level anyway. Wrong.

In the simplistic world of cardiology you lower blood lipids by lowering dietary fat. Under this intensely stupid idea it is impossible to lower lipoprotein(a) by dietary means.

Of course you could still go on and try that low fat idea. The Fins tried it. They, like most of the world, follow the low fat line in heart disease prevention. Just take 37 women who are already down at 70g fat per day (appallingly low to begin with) and reduce it to either 56g with minimal veggies or 59g with lots of healthy veggies plus nuts. Then flip the diets in a crossover study. Let's see what happens to lipoprotein(a). Both diets crank up lipoprotein(a). The 56g low veggie diet increase lipoprotein(a) by 7%. With those lovely veggies it cranked up by 9%. Note, another confirmation that fruit and veggies are BAD.

The converse has been nicely done. Just use a LC diet and lipoprotein(a) drops by 11.3%

Genetically determined hey? Duh.

Oh, and look how the low fat diet, with or without veggies, oxidised the LDL cholesterol. Low fat diets are very nice if you are in the cardiac business. As these squirming editors seem to be. What a load of twaddle. Bad is good. Really. It's good. Really, bad is good.

How many fingers, Winston?

Peter

1 comment:

Stephan said...

Peter,

I thought you might be interested in some Kitavan vs Swedish lipoprotein(a) numbers.

Males: from 20-39, Kitavans are at 172 U/L vs 252 for Swedes. 40-59 is 193 vs 345. 60-86 is 361 vs 231. It's strange, it reverses at the end for males.

Females: from 20-39, Kitavans are at 178 and Swedes 199. From 40-59, it's 280 vs 401. At 60-86, it's 305 vs 409.

None of it is significant except males from 40-59 because the standard deviations are almost as big as the numbers themselves.

It's also considerably higher in Kitavan smokers than nonsmokers, but again it's not significant.

I'd send you the paper but all I have is a photocopy from the library! Anyway, there's lots more blood lipid/lipoprotein data in here so let me know if you want any other numbers.