Effects of Fermented Garlic Extract Containing Nitric Oxide Metabolites on Blood Flow in Healthy Participants: A Randomized Controlled Trial

Abstract

Aged or fermented garlic extract (FGE) is a natural remedy that improves vascular function through increasing vascular nitric oxide (NO) bioavailability. This is because nitrite (NO2−), a NO metabolite, can be produced through bioconversion with macrobacteria during the fermentation of foods like garlic. We aimed to evaluate the effects of NO2− in FGE on blood flow (BF), blood pressure (BP), velocity of the common carotid artery (CCA) and internal carotid artery (ICA), regional cerebral BF (rCBF), and peripheral BF (PBF). The study was divided into two parts: (1) Thirty healthy adults were divided into FGE and placebo groups to compare BP and velocity of the CCA and ICA; and (2) Twenty-eight healthy adults were divided into FGE and placebo groups to compare rCBF and PBF and determine changes before/after ingestion. Significant changes were noted in BP and the velocity of both CCA 30–60 min after FGE ingestion. FGE ingestion resulted in significant increases in rCBF and increases in body surface temperature through alterations in PBF. No detectable clinical side effects were noted. Overall, oral administration of NO2− containing FGE demonstrated acute positive effects in upregulating BF, including the CCA, BP, rCBF, and PBF. Follow-up studies with larger sample sizes and long-term ingestion may be needed.