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The Diet-Heart Hypothesis: Subdividing Lipoproteins
Two posts ago, we made the rounds of the commonly measured blood lipids (total cholesterol, LDL, HDL, triglycerides) and how they associate with cardiac risk. It's important to keep in mind that many things associate with cardiac risk, not just blood lipids. For example, men with low serum vitamin D are at a 2.4-fold greater risk of heart attack than men with higher D levels. That alone is roughly equivalent to the predictive power of the blood lipids you get measured at the doctor's office. Coronary calcium scans (a measure of blood vessel calcification) also associate with cardiac risk better than the most commonly measured blood lipids.

Lipoproteins Can be Subdivided into Several Subcategories

In the continual search for better measures of cardiac risk, researchers in the 1980s decided to break down lipoprotein particles into sub-categories. One of these researchers is Dr. Ronald M. Krauss. Krauss published extensively on the association between lipoprotein size and cardiac risk, eventually concluding (source):

The plasma lipoprotein profile accompanying a preponderance of small, dense LDL particles (specifically LDL-III) is associated with up to a threefold increase in the susceptibility of developing [coronary artery disease]. This has been demonstrated in case-control studies of myocardial infarction and angiographically documented coronary disease.

Krauss found that small, dense LDL (sdLDL) doesn't travel alone: it typically comes along with low HDL and high triglycerides*. He called this combination of factors "lipoprotein pattern B"; its opposite is "lipoprotein pattern A": large, buoyant LDL, high HDL and low triglycerides. Incidentally, low HDL and high triglycerides are hallmarks of the metabolic syndrome, the quintessential modern metabolic disorder.

Krauss and his colleagues went on to hypothesize that sdLDL promotes atherosclerosis because of its ability to penetrate the artery wall more easily

Intima-media thickness of the carotid artery and the distribution of lipoprotein subclasses in men aged 40 to 49 years between whites in the United States and the Japanese in Japan for the ERA JUMP study.
Sekikawa A, Ueshima H, Sutton-Tyrrell K, Kadowaki T, El-Saed A, Okamura T, Takamiya T, Ueno Y, Evans RW, Nakamura Y, Edmundowicz D, Kashiwagi A, Maegawa H, Kuller LH.
Metabolism. 2008 Feb;57(2):177-82.
PMID: 18191046
doi: 10.1016/j.metabol.2007.08.022.

In men in the post World War II birth cohort, i.e., men aged 40-49, whites in the United States (U.S.) had significantly higher levels of intima-media thickness of the carotid arteries (IMT) than the Japanese in Japan.

The whites had significantly higher levels of large very-low-density-lipoprotein particles and significantly lower levels of large high-density-lipoprotein particles than the Japanese, whereas the two populations had similar levels of small low-density-lipoprotein particles. The two populations had similar associations of IMT with NMR lipoproteins. Adjusting for NMR lipoproteins did not attenuate the significant difference in IMT between the two populations (0.671 ± 0.006 for the whites and 0.618 ± 0.006 mm for the Japanese, P=0.01, mean (standard error)). Differences in the distributions of NMR lipoproteins between the two populations did not explain the higher IMT in the whites.

Effects of daily ingestion of chilli on serum lipoprotein oxidation in adult men and women.
Ahuja KD, Ball MJ.
Br J Nutr. 2006 Aug;96(2):239-42.
PMID: 16923216

In conclusion, regular consumption of chilli for 4 weeks increases the resistance of serum lipoproteins to oxidation.

Separate effects of reduced carbohydrate intake and weight loss on atherogenic dyslipidemia -- Krauss et al. 83 (5): 1025 -- American Journal of Clinical Nutrition
Changes in peak LDL diameter (Table 2) and mass concentrations of LDL subfractions (Table 3) induced by each of the diets were reflected by changes in the proportions of subjects exhibiting LDL subclass pattern B (Figure 2). There were linear reductions in the prevalence of pattern B as a function of reduced carbohydrate intake after both the stable-weight and weight-loss periods. However, the slopes of these relations differed (P = 0.04) such that the magnitude of the reduction in expression of pattern B induced by weight loss increased in association with the percentage of carbohydrate intake.

Conclusions: Moderate carbohydrate restriction and weight loss provide equivalent but nonadditive approaches to improving atherogenic dyslipidemia. Moreover, beneficial lipid changes resulting from a reduced carbohydrate intake were not significant after weight loss.

Separate effects of reduced carbohydrate intake and weight loss on atherogenic dyslipidemia.
Krauss RM, Blanche PJ, Rawlings RS, Fernstrom HS, Williams PT.
Am J Clin Nutr. 2006 May;83(5):1025-31; quiz 1205. Erratum in: Am J Clin Nutr. 2006 Sep;84(3):668.
PMID: 16685042

Modification of lipoproteins by very low-carbohydrate diets.
Volek JS, Sharman MJ, Forsythe CE.
J Nutr. 2005 Jun;135(6):1339-42. Review.
PMID: 15930434

Spiller GA, Jenkins DJ, Cragen LN, Gates JE, Bosello O, Berra K, Rudd C, Stevenson M, Superko R.Effect of a diet high in monounsaturated fat from almonds on plasma cholesterol and lipoproteins.J Am Coll Nutr. 1992 Apr;11(2):126-30.PMID: 1315812 [Pub

Ordovas JM.
The quest for cardiovascular health in the genomic era: nutrigenetics and plasma lipoproteins.
Proc Nutr Soc. 2004 Feb;63(1):145-52. Review.
PMID: 15070444 [PubMed - indexed for MEDLINE]

Goodrow EF, Wilson TA, Houde SC, Vishwanathan R, Scollin PA, Handelman G, Nicolosi RJ.
Consumption of one egg per day increases serum lutein and zeaxanthin concentrations in older adults without altering serum lipid and lipoprotein cholesterol concentra

Jenkins DJ, Kendall CW, Marchie A, Parker TL, Connelly PW, Qian W, Haight JS, Faulkner D, Vidgen E, Lapsley KG, Spiller GA. Dose response of almonds on coronary heart disease risk factors: blood lipids, oxidized low-density lipoproteins, lipoprotein(a),