Cholesterol feeding increases C-reactive protein and serum amyloid A levels in lean insulin-sensitive subjects

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.

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 (SI): lean insulin sensitive (LIS), mean+/-SEM BMI, 23.2+/-0.3 kg/m2, and SI, 6.7+/-0.3x10(-4)min(-1)/(microU/mL), n=66; lean insulin resistant (LIR), BMI, 24.5+/-0.2 kg/m2 and SI, 2.9+/-0.1x10(-4)min(-1)/(microU/mL), n=76; or obese insulin resistant (OIR), BMI, 31.4+/-0.5 kg/m2 and SI, 2.1+/-0.1x10(-4)min(-1)/(microU/mL), n=59. Insulin resistance and obesity each were associated with increased baseline levels of both CRP (P for trend, <0.001) and SAA (P for trend=0.015). Egg feeding was associated with significant increases in both CRP and SAA in the LIS group (both P<0.01) but not in the LIR or OIR groups. Egg feeding also was associated with a significant increase in non-HDL cholesterol (P<0.001) in LIS subjects; however, there was no correlation between the change in non-HDL cholesterol or changes in either CRP or SAA in this group.

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.