Hundreds of studies support garlic’s cardiovascular benefits. Now a six-week clinical trial in Nutrients
shows that a fermented form of garlic — aged black garlic extract — helps lower blood pressure in people with high cholesterol. Aged black garlic has long been a staple in Asian cuisine, where it’s considered a delicacy and loved for its jelly-like consistency.
For the randomized, crossover, double-blind study, researchers gave subjects with moderate hypercholesterolemia 250 mg daily of aged black garlic extract (ABG), standardized to contain S-allyl-L-cysteine (SAC), or a placebo. Significant reductions in diastolic blood pressure (DBP) were seen in those taking ABG compared to the placebo, especially in men with DBP great than 75 mm Hg. The average DBP reduction among the treatment group was 5.85 mm Hg, which substantially cuts the risk of stroke and other vascular events.
“The suggested mechanisms of action by which aged garlic could modulate blood pressure involve antioxidant activity by organosulfur compounds, such as SAC, in addition to allicin-derived polysulfides and the NOx and hydrogen sulfide signaling pathways, the regulation of transcription factors involved in hypertension, and ACE regulation. Some of them have already been identified in the current ABG extract: antioxidant proper- ties in vitro, improvement of vasodilation and levels of iNOS and eNOS, and regulation of the expression and levels of proinflammatory TNF-α,” say study authors.
It’s also interesting to note that aging produces biochemical changes in garlic, which distinguishes it from fresh garlic and may account for its unique health benefits.
At 6 weeks, the consumption of 250 mg of ABG extract with 1.25 mg of SAC significantly decreased DBP in moderately hypercholesterolemic subjects. The potential beneficial effects of ABG could be better observed in men and in nonoptimal DBP populations. Further studies performed in subjects with elevated blood pressure or grade 1 hypertension are needed to elucidate the specific contribution of SAC to the promising antihypertensive effects observed with this aged black garlic extract.