Efficacy of Watercress (Nasturtium officinale R.Br.) Consumption on Blood Pressure, Oxidative Stress Biomarkers, and Estimated Cardiovascular Risk in Thai Middle-Aged Adults: A Randomized Placebo-Controlled Pilot Study

Watercress (Nasturtium officinale R.Br.) is a cruciferous vegetable rich in bioactive compounds that may improve cardiovascular disease (CVD) risk factors. However, clinical evidence regarding its direct impact on CVD risk remains limited. This study evaluated the efficacy of watercress consumption on cardiovascular parameters, oxidative stress biomarkers, and estimated CVD risk in middle-aged Thai adults with low-to-moderate risk. Twenty-five participants completed the randomized, placebo-controlled pilot study. The watercress group (n = 12) consumed 16 dried watercress capsules daily for four weeks, while the placebo group (n = 13) received a placebo. Physical examinations, arterial stiffness, lipid profiles, and biochemical biomarkers were analyzed at baseline and the end of treatment. The 10-year CVD risk was estimated using the Framingham equation. Following the intervention, the watercress group showed significant reductions in both systolic and diastolic blood pressure compared to the placebo group. Within the watercress group, significant improvements from baseline to post-intervention were observed in oxidized LDL, antioxidant capacity (ABTS), and estimated 10-year CVD risk score. However, these three parameters did not reach statistical significance when compared to the placebo group. In conclusion, daily watercress consumption significantly lowers blood pressure and demonstrates a potential dietary option for supporting cardiovascular health. Nevertheless, larger and longer-term clinical trials remain necessary.