Inflammatory Cytokine Responses to 6 Wks of Increased Dairy Intake in Individuals with Overweight and Obesity-A Randomized Crossover Trial.

BACKGROUND

Dairy products are important sources of macro/micronutrients and contain bioactive components with anti-inflammatory, antioxidant, and musculoskeletal supporting properties. Few studies have assessed the short-term effect of consuming a variety of wholefood dairy products (as opposed to single foods/nutrients) on a range of interrelated inflammatory, metabolic, antioxidant and vascular outcomes.

OBJECTIVES

To compare these physiological outcomes after 6 wks of a high mixed-dairy diet compared with 6 wks of a low dairy diet.

METHODS

Using a randomly assigned crossover design, 30 adults (18 females/12 males) with overweight/obesity (OW/OB) (BMI: 32.0 ± 4.5 kg/m2] and pre-existing cardiometabolic disease risk factors completed two 6-wk dietary intervention conditions in random order (separated by a ≥4-wk washout); 1) a high-dairy (HD) diet (3 servings/d of a mix of low-fat milk, Skyr yogurt, full-fat cheddar cheese) and 2) their habitually low-dairy (LD) diet (≤1 serving/d). At baseline and then 6 wks later, fasted blood samples were collected, body composition was assessed, and vascular measurements were taken.

RESULTS

After controlling for age, BMI, sequence and period, there were no condition∗time interactions for interleukin-6 (IL-6; primary endpoint); however, there were condition∗time interactions for tumor necrosis factor-alpha (TNF-α; P = 0.042), and IL-4 (P = 0.026) such that they decreased and increased, respectively, on the HD diet compared with the LD diet. No other condition∗time interactions were observed for the other outcomes but we did observe sex∗condition interactions for IL-6 (P = 0.011), TNF-α (P < 0.001), triglycerides (P = 0.014), and diastolic blood pressure (P = 0.045), which were higher during the HD condition in males.

CONCLUSIONS

Increasing mixed dairy product intake for 6 wks favorably modulated some cytokines in the absence of metabolic, vascular, body weight, or fat changes. Differences in biomarker concentrations in relation to dairy intake and/or exercise may also be influenced by sex; however, this should be further explored. Overall, increased dairy intake may help ameliorate inflammation in individuals with OW/OB and cardiometabolic dysfunction. This trial was registered at clinicaltrials.gov as NCT04902417.