Date:

October 12, 2017

Source:

Penn State

Summary:

For the
broccoli haters of the world, researchers may have more bad news: the vegetable
may also help promote a healthy gut.

For the broccoli haters
of the world, researchers may have more bad news: the vegetable may also help
promote a healthy gut.

In a study, when mice ate
broccoli with their regular diet, they were better able to tolerate digestive
issues similar to symptoms of leaky gut and colitis than mice that were not
placed on a broccoli-supplemented diet, according to Gary Perdew, the John T.
and Paige S. Smith Professor in Agricultural Sciences, Penn State. He added
that other vegetables, like brussels sprouts and cauliflower, may also have
similar gut health properties.

“There are a lot of
reasons we want to explore helping with gastrointestinal health and one reason
is if you have problems, like a leaky gut, and start to suffer inflammation,
that may then lead to other conditions, like arthritis and heart disease,”
said Perdew. “Keeping your gut healthy and making sure you have good
barrier functions so you’re not getting this leaky effect would be really
big.”

Good intestinal barrier
function means that the gastrointestinal tract is helping protect the
intestines from toxins and harmful microorganisms, while allowing nutrients to
pass into the system, he said.

According to Perdew, the
key to the process may be a receptor in the gut called Aryl hydrocarbon
receptor, or AHR. The receptor helps the body regulate its reaction to certain
environmental contaminants, as well as triggers other responses to toxin
exposure.

The researchers, who
released their findings in the current issue of the Journal of Functional
Foods, suggest that cruciferous vegetables — such as broccoli, brussels
sprouts and cabbage — contain an organic chemical compound called indole
glucosinolates, which breaks down into other compounds, including
indolocarbazole — ICZ — in the stomach.

When ICZ binds to and
activates the Aryl hydrocarbon receptor (AHR) in the intestinal lining, it aids
in maintaining a healthy balance in the gut flora and immune surveillance, and
enhances host barrier function, according to the researchers. This may help
prevent diseases, such as various cancers and Crohn’s Disease, caused by
inflammation in the lining of the gut.

According to Perdew,
hyper-activating the AHR can cause toxicity, but using broccoli to activate the
receptor locally — in the gut — rather than systemically might help avoid
some of these problems. “Dioxin, for example, activates this receptor, and
if you hyper-activate it with dioxin, it will cause toxicity,” said
Perdew. “What we were interested in is: Could you locally activate the
receptor naturally at a level that would cause only modest AHR activation in
the gut, but not cause systemic activation, which could possibly lead to
negative effects?”

The researchers used two
genetic lines of mice in the study to focus on AHR. One line had a low ability
to bind ICZ to AHR, while the other line had a high ability to bind ICZ to AHR.
They added 15 percent broccoli to the diets of both groups of mice. After
adding a substance that causes digestive problems, the researchers said that
the mice with a higher ability to bind ICZ to the AHR were protected from a
chemical that induced digestive problems, but the mice with the lower affinity
suffered from the toxic insult.

For humans, the amount in
the experiment would be equivalent to eating about 3.5 cups of broccoli each
day, according to Perdew. “Now, three and a half cups is a lot, but it’s
not a huge amount, really,” said Perdew. “We used a cultivar — or
variety — with about half the amount of this chemical in it, and there are
cultivars with twice as much. Also, brussels sprouts have three times as much,
which would mean a cup of brussels sprouts could get us to the same
level.”

Because people with
certain digestive conditions, such as colitis, are often warned to avoid too
much roughage in their diets, future research may include determining the best
ways for people to consume the broccoli — or other vegetables with similar
effects — to receive the same health benefits, without causing any other
associated digestive problems from the fibrous vegetables.

Story Source:

Materials provided by Penn State. Note:
Content may be edited for style and length.

Journal Reference:

1.    Troy D. Hubbard, Iain A.
Murray, Robert G. Nichols, Kaitlyn Cassel, Michael Podolsky, Guray Kuzu, Yuan
Tian, Phillip Smith, Mary J. Kennett, Andrew D. Patterson, Gary H. Perdew. Dietary
broccoli impacts microbial community structure and attenuates chemically
induced colitis in mice in an Ah receptor dependent manner. Journal of
Functional Foods, 2017; 37: 685 DOI: 10.1016/j.jff.2017.08.038