Dairy product consumption has no impact on biomarkers of inflammation among men and women with low-grade systemic inflammation

Abstract

Background: Randomized controlled trials specifically designed to assess inflammation-related outcomes in response to dairy consumption are lacking. Objective: We investigated the impact of dairy food consumption on biomarkers of inflammation in healthy men and women with low-grade systemic inflammation. Methods: In a multicenter randomized crossover study, 112 adult men and women with high-sensitivity C-reactive protein (hs-CRP) values >1 mg/L consumed 3 servings/d of dairy (375 mL low-fat milk, 175 g low-fat yogurt, and 30 g regular-fat cheddar cheese) or energy-matched control (fruit juice, vegetable juice, cashews, and 1 cookie) products as part of prudent 4-wk diets, each separated by a 4- to 8-wk washout period. Serumconcentrations of inflammation biomarkers weremeasured at the beginning and end of each dietary phase. Expression levels of key inflammatory genes and transcription factors in whole blood cells were assessed at the end of each diet by real-time polymerase chain reaction in a random subset of 53 subjects. Results: Analysis of within-diet changes (post- vs. prediet values) showed a significant reduction in hs-CRP concentrations after the control diet (211.7%, P = 0.05) but no change after the dairy diet (27.3%, P = 0.47). As a result, changes in hs-CRP differed between the dairy and control diets (P = 0.04). Both the control and dairy diets similarly reduced interleukin-6 concentrations compared with diet-specific baseline values (217.6% and 219.9%, respectively; P > 0.0001 for both, P = 0.77 for between-diet comparison). No between- or within-diet difference was observed in adiponectin concentrations, and there was also no between-diet difference in the expression of inflammatory genes and transcription factors. Conclusion: Consistent with data from previous work, these results suggest that short-term consumption of a combination of low- and high-fat dairy products as part of a healthy diet has no adverse effects on inflammation.