Broccoli compound may help prevent respiratory inflammation

Eating high amounts of broccoli, Brussels sprouts and cabbage daily may reduce the risk of respiratory inflammation that causes conditions like asthma, allergic rhinitis and chronic obstructive pulmonary disease, according to a new study.

March 2, 2009 (foodconsumer.org) -- Eating high amounts of broccoli, Brussels sprouts, and cabbage daily may reduce the risk of respiratory inflammation that causes conditions like asthma, allergic rhinitis, and chronic obstructive pulmonary disease, according to a new study.

The study, published in the March 2009 issue of the journal Clinical Immunology, shows that the sulforaphane found in cruciferous vegetables like broccoli increases production of antioxidant enzymes in the human airway.

Antioxidant enzymes are believed to protect against free radicals in polluted air, pollen, diesel exhaust, and tobacco smoke that can cause oxidative tissue damage and inflammation, leading to respiratory conditions like asthma.
   
"We found a two- to three-fold increase in antioxidant enzymes in the nasal airway cells of study participants who had eaten a preparation of broccoli sprouts," Dr. Marc Riedl of the David Geffen School of Medicine at UCLA said.

"This strategy may offer protection against inflammatory processes and could lead to potential treatments for a variety of respiratory conditions." 

For the study, 65 people volunteered to use varying oral doses of either broccoli or alfalfa sprout preparations for three days. Broccoli sprout preparation contains high levels of sulforaphane while the alfalfa preparation does not contain the compound.

The researchers tested rinses of nasal passages at the beginning and end of the study; in those who received 100 grams or more of broccoli sprout preparation, antioxidant enzymes were significantly increased as compared to the placebo group.

The best broccoli sprout dosage was 200 grams which generated a 101-percent increase of an antioxidant enzyme known as GSTP1 and a 199-percent increase of another key enzyme called NQO1.

"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," Riedl said.

By David Liu, Ph.D., and edited by Heather Kelley.