Herbs and spices at a relatively high culinary dosage improves 24-hour ambulatory blood pressure in adults at risk of cardiometabolic diseases: a randomized, crossover, controlled-feeding study

Background Intake of a single meal containing herbs and spices attenuates postprandial lipemia, hyperglycemia, and oxidative stress, and improves endothelial function. There has been limited investigation of the effect of longer-term intake of mixed herbs and spices on risk factors for cardiometabolic diseases. Objectives The objective was to assess the effect of an average American diet containing herbs and spices at 0.5 (low-spice diet; LSD), 3.3 (moderate-spice diet; MSD), and 6.6 (high-spice diet; HSD) g center dot d(-1) center dot 2100 kcal(-1) on lipids and lipoproteins as well as other risk factors for cardiometabolic diseases in at-risk adults. Methods A 3-period, randomized, crossover, controlled-feeding study with 71 participants was conducted at the Pennsylvania State University. Each diet was consumed for 4 wk with a minimum 2-wk washout period. Outcomes were assessed at baseline and the end of each diet period. Results No between-diet effects were observed for LDL cholesterol, the primary outcome. Between-diet differences were observed for mean 24-h systolic (P = 0.02) and diastolic (P = 0.005) ambulatory blood pressure. The HSD lowered mean 24-h systolic blood pressure compared with the MSD (-1.9 mm Hg; 95% CI: -3.6, -0.2 mm Hg; P = 0.02); the difference between the HSD and LSD was not statistically significant (-1.6 mm Hg; 95% CI: -3.3, 0.04 mm Hg; P = 0.058). The HSD lowered mean 24-h diastolic blood pressure compared with the LSD (-1.5 mm Hg; 95% CI: -2.5, -0.4 mm Hg; P = 0.003). No differences were detected between the LSD and MSD. No between-diet effects were observed for clinic-measured blood pressure, markers of glycemia, or vascular function. Conclusions In the context of a suboptimal US-style diet, addition of a relatively high culinary dosage of mixed herbs and spices (6.6 g center dot d(-1) center dot 2100 kcal(-1)) tended to improve 24-h blood pressure after 4 wk, compared with lower dosages (0.5 and 3.3 g center dot d(-1) center dot 2100 kcal(-1)), in adults at elevated risk of cardiometabolic diseases. This trial was registered at clinicaltrials.gov as NCT03064932.