Cruciferous Vegetables & Blood Pressure

The results of a small but randomized and controlled crossover trial were recently published in BMC Medicine, suggesting that cruciferous vegetables may lower systolic blood pressure, at least to a greater degree than squash and root vegetables. Known as the VEgetableS for vaScular hEaLth (VESSEL) study, 18 participants completed this controlled trial in which they were assigned 2 weeks of a diet rich in cruciferous vegetables or 2 weeks of a diet rich in root and squash vegetables, in random order. Between the ages of 56 to 72, these participants had moderately elevated blood pressure, with a mean systolic blood pressure (SBP) of 135.9 mmHg and a diastolic blood pressure of 76.4 mmHg at baseline.

During the active 2 weeks the median intake was 300g of cruciferous vegetables (broccoli, kale, cauliflower, and cabbage) per day, consumed as soups for lunch and dinner. The control group consumed similar soups comprised of 300g of root and squash vegetables (potato, sweet potato, carrot, and pumpkin) per day. The only other significant difference in diets between the diets was a slightly higher protein consumption during the cruciferous period (63g vs 56g per day).

The 24-hour SBP was significantly reduced following the cruciferous vs. control period by a mean difference of 2.5 mmHg, driven by a reduction in daytime SBP of 3.6 mmHg. As noted by the authors, previous research suggests this may translate into a 5% lower risk for major cardiovascular events. While no specific mechanism was established, glucosinolates levels were higher (indicated by the marker sulforaphane) following the cruciferous period of the diet, compounds known to have many related biological effects, including an upregulation in a critical transcription factor for antioxidant enzymes, nuclear erythroid 2-related factor 2 (Nrf2).