Study: Broccoli may help prevent respiratory conditions like asthma

WASHINGTON, March 2 (Chinese media) -- Here's another reason to eat your broccoli:

researchers from University of California in Los Angeles (UCLA) report that a

naturally occurring compound found in broccoli and other cruciferous vegetables

may help protect against respiratory inflammation that causes conditions like

asthma, allergic rhinitis and chronic obstructive pulmonary disease.

Published in the March edition of the journal Clinical Immunology, the

research shows that sulforaphane, a chemical in broccoli, triggers an increase

of antioxidant enzymes in the human air way, which offer protection against the

onslaught of free radicals that people breathe in every day in polluted air,

pollen, diesel exhaust and tobacco smoke.

A supercharged form of oxygen, free radicals can cause oxidative tissue

damage, which leads to inflammation and respiratory conditions like asthma.

"This is one of the first studies showing that broccoli sprouts-- a readily

available food source -- offered potent biologic effects in stimulating an

antioxidant response in humans," said Marc Riedl, the study's principal

investigator and an assistant professor of clinical immunology and allergy at

the David Geffen School of Medicine at UCLA.

"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," Riedl said. "This strategy may offer protection against inflammatory

processes and could lead to potential treatments for a variety of respiratory

conditions."

The UCLA team worked with 65 volunteers who were given varying oral doses

of either broccoli or alfalfa sprouts preparations for three days. Broccoli

sprouts are the richest natural source of sulforaphane; the alfalfa sprouts,

which do not contain the compound, served as a placebo.

Rinses of nasal passages were collected at the beginning and end of the

study to assess the gene expression of antioxidant enzymes in cells of the upper

airways. Researchers found significant increases of antioxidant enzymes at

broccoli sprout doses of 100 grams and higher, compared with the placebo group.

The maximum broccoli sprout dosage of 200 grams generated a 101-percent

increase of an antioxidant enzyme called 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.

According to the authors, no serious side effects occurred in study

participants receiving broccoli sprouts, demonstrating that this may be an

effective, safe antioxidant strategy to help reduce the inflammatory impact of

free radicals.

Riedl notes that more research needs to be done to examine the benefits of

sulforaphane for specific respiratory conditions. It is too early to recommend a

particular dosage. However, he recommends including broccoli and other

cruciferous vegetables as part of a healthy diet.