Effects of an isocaloric healthy Nordic diet on ambulatory blood pressure in metabolic syndrome: a randomized SYSDIET sub-study

BACKGROUND/OBJECTIVES: Dietary pattern is central in the prevention of hypertension and blood pressure (BP)-related diseases. A diet based on healthy Nordic foods may have a favourable impact on BP. The objective was to clarify whether a Nordic alternative for a healthy food pattern would have beneficial effects on ambulatory BP in subjects with metabolic syndrome (MetS). SUBJECTS/METHODS: In total, 37 subjects were randomized to either a healthy Nordic diet or a control diet. A healthy Nordic diet embraced whole grains, rapeseed oil, berries, fruits, vegetables, fish, nuts and low-fat dairy products of Nordic origin. The mean nutrient intake in the Nordic countries formed the control diet, embracing wheat products, dairy fat-based spread and a lower intake of fruits, vegetables and fish. Diets were isoenergetic. Ambulatory BP was monitored and 24-h urine was collected before and after 12 weeks of intervention. RESULTS: After 12 weeks, ambulatory diastolic BP (-4.4 mm Hg; P = 0.001) and mean arterial pressure (-4.2 mm Hg; P = 0.006) were lowered by the healthy Nordic diet compared with the control diet, whereas changes in ambulatory systolic BP did not differ significantly between diets (-3.5 mm Hg; P = 0.122). Heart rate tended to be lower in those on the healthy Nordic diet (P = 0.057). Urinary sodium and potassium excretions were unaffected by diets and consequently not associated with the healthy Nordic diet-induced lowering of BP. CONCLUSIONS: Consumption of Nordic varieties of health-enhancing foods for 12 weeks decreased diastolic ambulatory BP and mean arterial pressure in subjects with features of MetS during weight-stable condition, suggesting beneficial effects of a healthy Nordic dietary pattern on ambulatory BP.