Effects of Diet and Exercise on Qualitative and Quantitative Measures of LDL and Its Susceptibility to Oxidation

• Published in: Arteriosclerosis, thrombosis, and vascular biology Vol. 16; no. 2; pp. 201 - 207
• Main Authors: Beard, Christopher M., Barnard, James R., Robbins, David C., Ordovas, Jose M., Schaefer, Ernst J.
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.02.1996; Hagerstown, MD Lippincott
• Subjects: Atherosclerosis (general aspects, experimental research); Biological and medical sciences; Blood and lymphatic vessels; Cardiology. Vascular system; Centrifugation, Density Gradient; Diet; Female; Humans; Lipid Peroxidation; Lipids - blood; Lipoproteins, LDL - blood; Lipoproteins, LDL - metabolism; Male; Medical sciences; Middle Aged; Particle Size; Physical Exertion; Vascular disease; Physical exercise; Human; Lipoprotein LDL; Diet; Atherosclerosis; Risk factor; Cardiovascular disease; Exploration; Oxidation
• ISSN: 1079-5642; 1524-4636
• DOI: 10.1161/01.ATV.16.2.201

The purpose of this study was to investigate the effects of an intensive diet and exercise program on the quantity and quality of LDL as well as its susceptibility to in vitro oxidation. The diet was low in fat (< 10% kcal) and cholesterol (< 100 mg/d), while high in complex, unrefined carbohydrates (> 70% kcal) and fiber (35 g/1000 kcal). The study was composed of 80 participants in a 3-week residential program where food was provided ad libitum and there was daily aerobic exercise, primarily walking. In each subject, preparticipation and postparticipation fasting blood samples were drawn and LDL was isolated via density gradient ultracentrifugation. LDL particle diameter was determined by gradient gel electrophoresis of serum (n = 23). Isolated LDL was either separated into 6 subfractions by saline gradient equilibrium ultracentrifugation (n = 26) or subjected to in vitro copper oxidation (n = 32). Significant reductions (P < .01) in serum levels of cholesterol (20%), LDL-cholesterol (20%), HDL-cholesterol (17%), triglycerides (26%), and glucose (16%) as well as in body weight (4%) were noted for the total population. The mean particle diameter of the LDL increased (24.2 plus/minus 0.2 to 25.1 plus/minus 0.14 nm, P < .01) and was correlated with the reduction in serum triglycerides (r = .58, P < .01). Six of 22 subjects changed in LDL phenotype from B (less or equal to 25.5 nm) to A (> 25.5 nm). The percentage of LDL-cholesterol carried in the more dense subfractions fell significantly, while that carried by the less dense fractions increased. Initial oxidation levels fell (21%), while the lag time before copper-induced oxidation increased (13%). Reductions were observed in both the rate of oxidation (16%) and peak oxidation (20%). All of these changes should result in a dramatic reduction in the risk for atherosclerosis and its clinical sequelae. (Arterioscler Thromb Vasc Biol. 1996;16:201-207.).