Title

Cardiometabolic effects of a carbohydrate restricted diet and increased physical activity in men and women taking statins

Date of Completion

January 2009

Keywords

Health Sciences, Nutrition

Degree

Ph.D.

Abstract

The effect of carbohydrate restriction and increased physical activity on statin treatment has not been examined. The objective of this study was to assess changes in LDL particle size, metabolic syndrome, and emerging cardiometabolic risk factors after a 6-week intervention. Twenty one men and postmenopausal women (mean±SD; age: 59.2±9.5 y, body weight: 89.2±16.8 kg, % body fat: 38.5±6.2%, body mass index: 29.52±3.03 kg/m 2) who had successfully lowered LDL-C with a statin (<130 mg/dl) were matched on sex, age, lipids, and type of statin and randomized to a very low carbohydrate ketogenic diet (LCD) or a low carbohydrate diet with increased physical activity (LCD+PA). Subjects received weekly dietary counseling from a registered dietitian and they were instructed to maintain body weight. Fasting blood and physiological measurements were taken at baseline, week 3, and week 6. LDL size was measured with non-gradient polyacrylamide gel electrophoresis and vertical auto profile ultracentrifugation. Food records (mean±SD; baseline: 2159±415 kcals, 45/36/20 %carb/fat/pro; intervention: 1739±481 kcals, 11/58/26 %carb/fat/pro), urine acetoacetic acid, and serum total ketones demonstrated dietary compliance. LCD+PA incrementally increased average daily steps using a pedometer, reaching 4,792 steps greater than baseline at week 6. LDL particle size (p≤0.05) and reactive hyperemia peak forearm blood flow significantly increased (p≤0.01) and TAG (-36%), insulin (-25%), systolic (-5%) and diastolic (-6%) blood pressure, body weight (-3%), and waist circumference (-4%) decreased. Change in body weight was not significantly correlated with changes in blood markers. There were no significant differences observed for total cholesterol, LDL-C, HDL-C, Lp(a), glucose, or flow-mediated dilation, nor were group differences found. These findings indicate that individuals on statin medication showing signs of metabolic syndrome respond favorably to a low carbohydrate diet as evidenced by further improvements in LDL particle size, TAG, insulin, and blood pressure. ^