Abstract
- Background
Higher habitual intake of cruciferous vegetables has consistently been associated with a reduced risk of cardiovascular disease in observational studies; however, the precise physiological pathways and causal mechanisms involved remain uncertain. This randomized controlled trial was designed to determine whether increased consumption of cruciferous vegetables (active intervention) effectively lowers 24-hour ambulatory brachial systolic blood pressure (SBP; the primary outcome) compared to root and squash vegetables (control intervention) in Australian adults presenting with mildly elevated blood pressure (clinic SBP ranging inclusively from 120 to 160 mm Hg).
- Methods
A rigorous randomized, controlled, crossover trial design was implemented in which participants completed two separate 2-week dietary intervention periods, separated by a 2-week washout phase. Participants consumed approximately 300 g/day of either cruciferous vegetables or root and squash vegetables incorporated into their lunch and dinner meals in a single-blinded fashion. Dietary adherence was rigorously tracked using detailed food diaries and objective circulating biomarkers, specifically S-methyl cysteine sulfoxide (SMCSO) as the active biomarker and carotenoids as the control biomarker. Twenty-four-hour brachial ambulatory systolic blood pressure and various secondary metabolic and hemodynamic outcomes were evaluated both pre- and post-intervention. Between-treatment differences were analyzed using linear mixed-effects regression models.
- Results
Eighteen adult participants were successfully recruited (median age: 68 years; 16 females; mean baseline clinic SBP: 135.9 $\pm$ 10.0 mm Hg). High dietary compliance was achieved, with 72% of participants demonstrating 100% adherence. Biochemical validation confirmed significant divergence in biomarker concentrations between the two interventions (mean difference for active vs. control SMCSO: 22.93 $\mu$g/mL, 95% CI: 15.62 to 30.23, $P < 0.0001$; for carotenoids: $-0.974$ $\mu$g/mL, 95% CI: $-1.525$ to $-0.423$, $P = 0.001$). Twenty-four-hour brachial systolic blood pressure was significantly reduced following the active cruciferous intervention compared to the control diet (mean difference: $-2.5$ mm Hg, 95% CI: $-4.2$ to $-0.9$, $P = 0.002$; active pre-intervention: 126.8 $\pm$ 12.6 mm Hg vs. post-intervention: 124.4 $\pm$ 11.8 mm Hg; control pre-intervention: 125.5 $\pm$ 12.1 mm Hg vs. post-intervention: 124.8 $\pm$ 13.1 mm Hg, $n = 17$). This reduction was predominantly driven by significant decreases in daytime SBP (mean difference: $-3.6$ mm Hg, 95% CI: $-5.4$ to $-1.7$, $P < 0.001$). Furthermore, serum triglyceride concentrations were significantly lower following the active cruciferous diet relative to the control condition (mean difference: $-0.2$ mmol/L, 95% CI: $-0.4$ to $-0.0$, $P = 0.047$).
- Conclusions
An increased dietary intake of cruciferous vegetables leads to a clinically meaningful reduction in systolic blood pressure compared to root and squash vegetables. Future investigations are warranted to determine whether targeted public health recommendations focusing on increasing cruciferous vegetable consumption can confer broad population-level cardiovascular health benefits.
https://pmc.ncbi.nlm.nih.gov/articles/PMC11367748/