 20% (P=0.01 for the interaction between diet group and time), as compared with a decrease of 12% in the low-fat group.
Variations in the size and density distributions of low-density lipoprotein (LDL) and high-density lipoprotein (HDL) particles have been related to risk for cardiovascular disease. In particular, increased levels of small, dense LDL particles, together with reduced levels of large HDL and increases in small HDL, are integral features of the atherogenic dyslipidemia found in patients with insulin resistance, obesity, and metabolic syndrome. Increased dietary carbohydrates, particularly simple sugars and starches with high glycemic index, can increase levels of small, dense LDL and HDL, primarily by mechanisms that involve increasing plasma triglyceride concentrations. Low-carbohydrate diets may have the opposite effects. Diets with differing fatty acid composition can also influence LDL and HDL particle distributions.
31 Evidence type: controlled experiment
Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet. Volek JS, Phinney SD, Forsythe CE, Quann EE, Wood RJ, Puglisi MJ, Kraemer WJ, Bibus DM, Fernandez ML, Feinman RD. Lipids. 2009 Apr;44(4):297-309. doi: 10.1007/s11745-008-3274-2. Epub 2008 Dec 12.
We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12-week study comparing two hypocaloric diets (approximately 1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable triacylglycerol (TAG) (-51%), HDL-C (13%) and total cholesterol/HDL-C ratio (-14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (-47%), the Apo B/Apo A-1 ratio (-16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant states, and only the CRD decreased this marker (-20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk.
32 Evidence type: randomized controlled trial
Effect of a low-carbohydrate, ketogenic diet program compared to a low-fat diet on fasting lipoprotein subclasses. Westman EC, Yancy WS Jr, Olsen MK, Dudley T, Guyton JR. Int J Cardiol. 2006 Jun 16;110(2):212-6. Epub 2005 Nov 16.
Comparing baseline to 6 months, the LCKD [low carb ketogenic diet] group had significant changes in large VLDL (-78%), medium VLDL (-60%), small VLDL (-57%), LDL particle size (+2%), large LDL (+54%), medium LDL (-42%), small LDL (-78%), HDL particle size (+5%), large HDL (+21%), and LDL particle concentration (-11%).
CONCLUSIONS: The LCKD with nutritional supplementation led to beneficial changes in serum lipid subclasses during weight loss. While the LCKD did not lower total LDL cholesterol, it did result in a shift from small, dense LDL to large, buoyant LDL, which could lower cardiovascular disease risk.
33 Evidence type: longitudinal analysis
Change in LDL particle size is associated with change in plasma triglyceride concentration. McNamara JR, Jenner JL,