Cholesterol Feeding Increases C-Reactive Protein and Serum Amyloid A Levels in Lean Insulin-Sensitive Subjects

Abstract

Background— Inflammatory markers associated with elevated cardiovascular risk are increased by cholesterol feeding in animal models. However, whether dietary cholesterol increases inflammatory marker levels in humans is not known. Methods and Results— C-reactive protein (CRP), serum amyloid A (SAA), and lipoprotein levels were compared in 201 healthy subjects on an American Heart Association–National Cholesterol Education Program step 1 diet at baseline and after addition of 4 eggs per day for 4 weeks. Subjects were classified a priori into 3 groups based on their body mass index (BMI) and insulin sensitivity index (S _I ): lean insulin sensitive (LIS), mean±SEM BMI, 23.2±0.3 kg/m ² , and S _I , 6.7±0.3×10 ⁻⁴ min ⁻¹ /(μU/mL), n=66; lean insulin resistant (LIR), BMI, 24.5±0.2 kg/m ² and S _I , 2.9±0.1×10 ⁻⁴ min ⁻¹ /(μU/mL), n=76; or obese insulin resistant (OIR), BMI, 31.4±0.5 kg/m ² and S _I , 2.1±0.1×10 ⁻⁴ min ⁻¹ /(μU/mL), n=59. Insulin resistance and obesity each were associated with increased baseline levels of both CRP ( P for trend, P for trend=0.015). Egg feeding was associated with significant increases in both CRP and SAA in the LIS group (both P P Conclusions— A high-cholesterol diet leads to significant increases in both inflammatory markers and non-HDL cholesterol levels in insulin-sensitive individuals but not in lean or obese insulin-resistant subjects.