Capsaicin, the active pungent of spicy foods, is the endogenous ligand of the transient receptor potential cation channel vanilloid subfamily member 1 (TRPV1). Experimental data show that TRPV1 activation leads to vasodilation, water retention and natriuresis - effects that may reduce blood pressure (BP). Recent data found an association between spicy food consumption and improved outcomes, including cardiovascular disease. Capsaicin-induced BP lowering might explain this protective effect. We therefore investigated the BP effects of TRPV1 activation by capsaicin in healthy subjects.Design and Method:
In this double blind, randomized, placebo-controlled, cross-over study, participants received either two doses of capsaicin (5.2–6.2 mg, 81.250–97.200 SHU) or matching placebo in random order on two different study days, separated by at least one week. In the 2-hour follow-up after the first dose, BP, heart rate (HR), cardiac output (CO) and systemic vascular resistance index (SVRI) using Omron and NexfinTM and both plasma and urine sodium were repeatedly measured. To challenge osmoregulation, we studied the same parameters for 4 hours after a water loading test (20 mL/kg in 20 minutes) combined with the second dose.Results:
We included 12 healthy male subjects (mean age: 23 years). Relative to placebo, 30 min after first capsaicin dose systolic BP significantly increased (after 2 hours: +2.8 ± 1.1 mmHg; p=0.02), but not diastolic BP (Fig 1A). The second capsaicin dose plus water load increased placebo-subtracted diastolic, but not systolic, BP with 4.2 ± 3.6 mmHg after 30 min (p = 0.04). Compared to placebo, capsaicin did affect neither water balance nor natriuresis (Fig 1B,C). Effects on HR, CO and SVRI did not differ from placebo.Conclusions:
In healthy subjects, capsaicin increased BP on the short term. We could not identify changes in systemic vascular resistance or water and sodium balance, which were thought to underlie the hypothesized BP effects. Whether long-term capsaicin has similar effects remains to be determined.