Abstract
Background: Garlic and sulfur-containing components of garlic have been reported to stimulate nitric oxide synthesis in the endothelium. Nitric oxide production is an important determinant of arterial stiffness.
Objective: To examine the impact of dried garlic powder tablets on arterial stiffness as assessed by measurements of pulse wave velocity (PWV).
Design: Two separate randomized crossover studies of healthy people (trial I: n /13; trial II: n /9) were conducted. On separate days, participants consumed a high-fat meal (50 g fat) supplemented with garlic powder tablets (8.4 mg alliin), and an identical, but unsupplemented meal. PWV (m s-1) was measured immediately before and 2–3 h after the test meal.
Results: The unsupplemented fatty meal resulted in a significant 5–6% postprandial increase in PWV in both trials (I: +0.19 m s-1, p =0.04; II: + 0.21 m s-1, p =0.02). In contrast, the supplemented meal was not associated with any postprandial PWV changes in either trial (I: -0.02 m s-1, p =0.31; II: 0.00 m s-1, p 0.95). In pooled analysis (trials I and II), the inhibitory effect of garlic powder on the fatty meal-induced postprandial PWV increase was statistically significant (+0.20 m s-1 vs -0.01 m s-1, p /0.01).
Conclusions: The postprandial increase in PWV associated with consumption of a high-fat meal seems to be prevented by dried garlic powder supplementation. Larger, blinded and placebo-controlled trials are needed to confirm the possible antiatherogenic effect.