Sulforaphane is found in many of the cruciferous veggies, like broccoli, cauliflower, cabbage, collards, and watercress, to name a few. Broccoli sprouts contain about 20 to 50 times the amount of sulforaphane as mature broccoli does. Researcher Marc A. Riedl and his team wondered if administering high concentrations of sulforaphane to participants would have an effect on the levels of antioxidant enzymes in the airways — specifically a group called Phase II enzymes, which scout out and rid the body of destructive particles known as reactive oxygen species. Sulforaphane has already been shown to increase the activity of Phase II enzymes under other circumstances.
Broccoli sprouts contain about 20 to 50 times the amount of sulforaphane as mature broccoli does.
To test their hypothesis, the researchers gave 65 men and women different concentrations of an oral preparation made from broccoli sprouts, over a period of three days. A control group was administered a preparation made of alfalfa sprouts, which do not contain sulforaphane. To measure the levels of the antioxidant enzymes of interest, the researchers rinsed the nasal passages of the subjects before and after the three-day study was complete; from the contents of the nasal fluids, they were able to determine the level of gene expression for the enzymes of interest.
They found that as the dose of sulforaphane increased, so did the amounts of antioxidant enzymes in the nasal passages -- by as much as two- to three-times.
"Based on this study, compounds in broccoli sprouts have a very potent effect in boosting the airway's self-defense system against oxidative stress," said Riedl. He also points out that a "major advantage of sulforaphane is that it appears to increase a broad array of antioxidant enzymes, which may help the compound's effectiveness in blocking the harmful effects of air pollution."
While there's no telling exactly how much broccoli one would have to eat to reap the potential benefits of sulforaphane on airway health, Riedl does say that adding broccoli and other cruciferous veggies to the diet is never a bad idea. Designing a treatment for airway disorders based on the results of this study may also be a possibly in the future.