Stroke is one of the leading causes of death and disability worldwide, claiming the lives of roughly 5 million people and leaving another 5 million permanently disabled every year. A 2013 study demonstrated that sulforaphane protects the brain during ischemic stroke via hormetic preconditioning.

Ischemic stroke occurs when blood flow to the brain is reduced or interrupted, starving neurons of oxygen and nutrients. Neuronal death occurs in the immediate area of a stroke within the first few hours of the incident, but nearby cells can be rescued with appropriate therapies. Heme oxygenase-1 (HO-1), an antioxidant enzyme, attenuates neuronal injury. Nrf2, a protein that regulates the expression of antioxidant and stress response proteins, induces HO-1 expression.

The authors of the study gave mice sulforaphane (5 milligrams per kilogram of body weight) or corn oil with saline via injection. After the mice experienced a stroke, the authors measured the animals' Nrf2 and HO-1 gene expression and assessed behavioral changes, blood-brain barrier integrity, and neurological deficits.

The mice that received sulforaphane treatment showed increased HO-1 expression, reduced blood-brain barrier damage, and fewer neurological deficits than mice that received the corn oil/saline. Levels of peroxynitrite, a short-lived reactive oxygen species associated with cell death, increased in the mice, suggesting that hormetic preconditioning mediated the protection sulforaphane provided against stroke.

These findings suggest that dietary or supplemental interventions (such as sulforaphane) that precondition the brain against injury offer promise as strategies to reduce complications associated with stroke.

• Link to study abstract.