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A recent study shows that molecules naturally found in cruciferous vegetables may protect the lungs from illness. skaman306/Getty Images
  • Research has shown that consuming a variety of vegetables provides a number of health benefits when consumed.
  • A recent study shows that molecules naturally found in cruciferous vegetables may help the lungs maintain a healthy barrier against infection.
  • The findings suggest that eating cruciferous veggies like leafy greens and broccoli could bolster immunity and preserve lung health.

For a very long time, doctors have urged people to eat more vegetables.

Not only are they nutritious, but previous research shows adding more veggies to a person’s diet can help reduce obesity risk, improve mental health, lower heart disease risk, and boost gut health.

In a recent study, researchers from the Francis Crick Institute in London have found that molecules naturally found in cruciferous vegetables — such as broccoli and cauliflower — can boost the activity of a protein called aryl hydrocarbon receptor (AHR), helping the lungs to maintain a healthy barrier against viral and bacterial infection.

The findings were recently published in the journal Nature.

Aryl hydrocarbon receptor (AHR) is a type of cellular protein. In the body, it assists with gene regulation and the metabolism of certain enzymes.

Previous research also shows AHR plays a role in regulating the immune system and plays an active role in stem cells.

Because of its relation to the immune system, scientists have studied the use of AHR as a potential target for prevention and therapies for a number of diseases, including:

In this study, researchers focused on the natural lung barrier that helps protect the lungs from pollution and infection.

The lung barrier includes two layers — one of endothelial cells and one of epithelial cells. This allows the barrier to keep out viruses and bacteria but still lets oxygen enter.

According to Dr. Andreas Wack, PhD, principal group leader of the Wack Lab Immunoregulation Laboratory at the Francis Crick Institute and lead author of this study, they decided to study the effect of AHR on lung barriers because it has been studied extensively at other barrier sites such as the skin and the gut, but much less so in the lung.

“AHR is an environmental sensor that can be activated by ligands found in food or produced by bacteria living in our gut — but some toxic ligands are also derived from air pollution. AHR protects the lung by inducing gene programs known to support barrier integrity and barrier function. Which genes are directly targeted by AHR and which ones are triggered indirectly is unclear.”

— Dr. Andreas Wack, PhD, lead study author

For the present study, Dr. Wack and his team performed a variety of experiments using a mouse model.

When mice were infected with the flu virus, scientists found blood in the airspaces in the lungs as it had leaked across the damaged lung barrier.

When AHR was overactivated, there was less blood in the lung spaces, indicating that it helped prevent the lung barrier from leaking.

During the study, scientists observed mice with increased AHR activity did not lose as much weight when infected with the flu virus. Additionally, the AHR-enhanced mice could better fight off bacterial infection and the already-introduced flu virus.

Researchers also found the flu infection caused a decrease in protective lung AHR activity only in mice fed AHR ligands in their diet before the illness.

Mice that consumed an AHR ligand-rich diet during infection had better lung barrier integrity and less lung damage than those on a control diet.

“In mice without ligands in the diet, their AHR activity levels were low to start with, so if you don’t eat ligands, you have little AHR activity,” Dr. Wack explained to Medical News Today.

“When you eat them, then AHR activity increases. This activity can be dampened by sick behavior, i.e., not eating for some days.”

“This is probably not a good idea, so keep eating a healthy diet to upkeep AHR activity,” he added. “What is good for your gut — a healthy, rich, (and) varied diet containing AHR ligands — is probably also good for your lungs.”

After reviewing this study, Dr. Elliot Eisenberg, assistant professor of medicine (pulmonary, critical care, and sleep medicine) at the Icahn School of Medicine at Mount Sinai, told MNT that the data was encouraging and demonstrated a potential protective effect of dietary intake on lung endothelial cell response to infection.

“As this is preclinical data, dietary recommendations for patients with influenza cannot be made,” Dr. Eisenberg said.

“[The study data] does provide biological plausibility to support future clinical and translational endeavors assessing diet and clinical outcomes and adds to the growing body of literature supporting the role of diet and lung health.”

“Prior clinical research, including studies by Mount Sinai, have demonstrated healthy diet attenuates wheezing among teens with secondhand smoke exposure, and is associated with (a) slower decline in lung function amongst young adults.”

— Dr. Elliot Eisenberg, pulmonary and internal physician

Cruciferous vegetables are part of a family of vegetables known as brassicas.

There are more than 3,000 different types of cruciferous vegetables. The most commonly known are:

In addition to providing the nutritional benefits all vegetables are known for, these veggies are also high in dietary fiber and rich sources of specific vitamins, including vitamins C, E, K, and B9 (folate).

Cruciferous vegetables also contain phytonutrients, which are compounds known to help lower inflammation. Previous studies have also linked phytonutrients to cancer treatment and prevention.

And these types of veggies naturally have chemicals called glucosinolates. Past studies have linked glucosinolates to potential cancer protection, such as gastrointestinal cancers.

Additionally, other studies have looked at using glucosinolates to help protect against cardiovascular and neurodegenerative diseases.

Health and nutrition experts recommend consuming 2 to 3 cups of vegetables daily as part of a healthy, balanced diet.