Effects of regular-fat and low-fat dairy consumption on daytime ambulatory blood pressure and other cardiometabolic risk factors: a randomized controlled feeding trial.

Background: The extent to which dairy products and their fat content influence cardiovascular health remains uncertain. Objective: This study aimed to assess how consumption of low-fat milk and regular-fat cheese enriched in gamma-aminobutyric acid (GABA) influences daytime ambulatory blood pressure (BP) and other cardiometabolic risk factors. Methods: In this crossover controlled feeding study. 55 healthy men and women with high-normal daytime BP were randomly assigned to sequences of three 6-wk isoenergetic diets, each comprising 1) no dairy (control diet), 2) 3 daily servings of 1% fat milk, and 3) 1 daily serving of 31% fat cheddar cheese naturally enriched in GABA. Total proteins, carbohydrates, and fats were matched across all 3 diets. The additional 2% of energy from SFAs in the cheese diet was replaced by n-6 PUFAs in the other diets. Results: Comparison of postdiet ambulatory systolic BP revealed no difference (P = 0.34), which was also the case for ambulatory diastolic BP (P = 0.45). The cheese diet increased serum LDL-cholesterol concentrations compared with the control and milk diets (+5.8%, P = 0.006 and +7.0%, P = 0.0008, respectively) and increased LDL particle size compared with the milk diet (P = 0.02). HDL-cholesterol concentrations after the milk diet were lower than after the control diet (-4.1%; P = 0.009). The milk and cheese diets increased triglycerides compared with the control diet (+9.9%, P = 0.01 and +10.5%, P = 0.007, respectively). There was no significant difference between all diets for C-reactive protein concentrations and markers of glucose/insulin homeostasis. Conclusions: These results suggest that short-term consumption of dairy products, whether low or regular in fat, has no overall effect on daytime ambulatory BP compared with a dairy-free diet. Other cardiometabolic risk factors may be differently modified according to the fat content of the dairy product.