Effect of diet-induced energy deficit and body fat reduction on high-sensitive CRP and other inflammatory markers in obese subjects.

AIMS: To dissociate the possible differential effects of negative energy balance and reduction in body fat mass (FM) on inflammatory markers: C-reactive protein (CRP), fibrinogen, interleukin-6 (IL-6), haptoglobin, transferrin and the adipokines leptin and adiponectin.

METHODS: Thirty-three obese subjects (BMI: 34.0+/-3.1 kg/m(2), age: 43.0+/-10.5 years, mean+/-s.d., 16 men) participated in a 20-week controlled dietary intervention divided into four periods. Weight reduction was induced by an 8-week low energy diet (3.4 MJ d(-1)) (LED-1) followed by a 4-week weight maintenance program (M-1). Subsequently participants underwent an additional 4-week LED (4.2 MJ d(-1)) (LED-2) followed by a final 4-week weight maintenance diet (M-2). Blood samples and anthropometrics were assessed at baseline and after LED-1, M-1, LED-2 and M-2.

RESULTS: Body weight was significantly reduced by 13% (13.7+/-4.0 kg, P<0.0001) after LED-1. However, a reduction in high-sensitive CRP (hs-CRP) by 35% (-1.1 (95% CI: -2.5:0.2) mg l(-1), P=0.02) only became apparent after LED-2, which produced an additional weight loss of 2.9 kg compared to baseline, and it was maintained after M-2 (-1.0 (-1.4:0.4) mg l(-1), P=0.02). Also IL-6 was reduced by 21% (-0.6 (-2.4:0.2) ng l(-1), P=0.02) after M-2. The reductions in hs-CRP and IL-6 were both associated with reduction in FM but not body weight. Haptoglobin, transferrin and leptin were significantly reduced after both LED-1 and LED-2, but increased during weight maintenance. Adiponectin was not significantly changed during the intervention.

CONCLUSIONS: The results suggest that, whereas haptoglobin and transferrin respond more rapidly and are more susceptible to the acute change in energy balance, a reduction in hs-CRP and IL-6 seems to be achieved by a reduction in FM when a new steady state has been established.