Effects of low-fat dairy consumption on markers of low-grade systemic inflammation and endothelial function in overweight and obese subjects: an intervention study

Although increased concentrations of plasma inflammatory markers are not one of the criteria to diagnose the metabolic syndrome, low-grade systemic inflammation is receiving large attention as a metabolic syndrome component and cardiovascular risk factor. As several epidemiological studies have suggested a negative relationship between low-fat dairy consumption and the metabolic syndrome, we decided to investigate the effects of low-fat dairy consumption on inflammatory markers and adhesion molecules in overweight and obese subjects in an intervention study. Thirty-five healthy subjects (BMI>27 kg/m²) consumed, in a random order, low-fat dairy products (500 ml low-fat milk and 150 g low-fat yogurt) or carbohydrate-rich control products (600 ml fruit juice and three fruit biscuits) daily for 8 weeks. Plasma concentrations of TNF-α were decreased by 0.16 (SD 0.50) pg/ml (P = 0.070), and soluble TNF-α receptor-1 (s-TNFR-1) was increased by 110.0 (SD 338.4) pg/ml (P = 0.062) after the low-fat dairy period than after the control period. s-TNFR-2 was increased by 227.0 (SD 449.0) pg/ml (P = 0.020) by the dairy intervention. As a result, the TNF-α index, defined as the TNF-α:s-TNFR-2 ratio, was decreased by 0.000053 (SD 0.00012) (P = 0.015) after the dairy diet consumption. Low-fat dairy consumption had no effect on IL-6, monocyte chemoattractant protein-1, intracellular adhesion molecule-1 and vascular cell adhesion molecule-1 concentrations. The present results indicate that in overweight and obese subjects, low-fat dairy consumption for 8 weeks may increase concentrations of s-TNFR compared with carbohydrate-rich product consumption, but that it has no effects on other markers of chronic inflammation and endothelial function.