Plant-powered prevention

Fujioka Fruits and Veggies

Patients often question oncologist and researcher Naomi Fujioka, M.D., about what they can do to live longer and feel better. They ask what diets they should follow or what supplements to take. Fujioka, a Masonic Scholar, can’t formally recommend anything other than a well-balanced diet, following national guidelines for the general population; however, she’s hopeful that she’ll have an answer in her lifetime.

Naomi Fujioka

“My overarching goal, possibly many years from now, is to be able to tell patients and healthy people that eating certain vegetables could prevent carcinogen-induced cancer, particularly tobacco-carcinogen related lung cancer,” Fujioka says.

The leading cause of lung cancer is smoking, which accounts for about 90 percent of cases. Lung cancer can go undetected in its early stages because symptoms often aren’t present. Once symptoms do appear, lung cancer can be tricky to diagnose because it shares symptoms with more common diagnoses like pneumonia, allergies, and colds.

“While the incidence of lung cancer in this country is actually dropping, the rate of smoking worldwide is increasing,” Fujioka says. “Lots of people are getting it, and lots of people are dying from it.”

Fujioka and her colleagues aim to change that through diet. Cruciferous vegetables like Brussels sprouts, broccoli, and kale contain compounds called glucosinolates that researchers say could change how people metabolize common carcinogens in tobacco smoke and the environment and reduce their risk of developing lung cancer. Researchers including Fujioka and her mentor Stephen Hecht, Ph.D., are advancing this work through several studies.

Studying supplements

University researchers have shown that indole-3-carbinol can prevent lung tumors in animals exposed to tobacco carcinogens. Indole-3-carbinol is produced when the glucosinolate glucobrassicin breaks down during the consumption of cruciferous vegetables. It’s also available as a supplement. In animals, the effect is enhanced when indole-3-carbinol is combined with silibinin, which is derived from milk thistle.

Now the group wants to study it in people, and the first step is to make sure the supplements are safe through a phase 1 clinical trial, which began in February 2019. In the trial, indole-3-carbinol and silibinin are given as supplements to current smokers who are healthy.

The team is drawing blood at certain intervals to determine how long the supplements last in the body and to see if combining indole-3-carbinol and silibinin will change the amount of time the supplements remain in the body. In addition, they are collecting data on how the supplements affect inflammation and impact immunity against cancer development.

“The relief of not having to constantly worry about the financial part of my research has meant a lot. I always feel like I have the freedom to try new ideas, and thanks to the Masons, I can obtain preliminary data. It’s that generation of preliminary data that leads to bigger grants, and that’s only possible with their support.”

Reaping benefits from food

Fujioka’s ultimate goal is for patients to be able to eat food to prevent cancer, rather than taking supplements or drugs.

“In this day and age, people are not going to take drugs to prevent cancer; there are just too many side effects,” she explains. “People are increasingly interested in nutrition and cancer prevention. The data in the lab is astonishing, so we’re really hopeful.” Further, supplements are more expensive and less practical than eating healthy foods.

To that end, the team’s third study on Brussels sprouts is underway after stalling because of difficulty consistently obtaining Brussels sprouts with high amounts of glucobrassicin; the amount the vegetables contain varies based on the variety and growing conditions.

A new supplier is allowing them to continue studying the effect the vegetables have on carcinogen metabolism. In the study, current and former smokers consume a fixed amount of raw Brussels sprouts.

After this study, Fujioka says they plan to find a more practical way for people to consume Brussels sprouts and other similar vegetables with glucobrassicin. Most people won’t eat them raw, but cooking the vegetables reduces the chemopreventive potential, she explains.

Researchers will also study watercress, which is a source of the chemopreventive agent Phenethyl isothiocyanate (PEITC). PEITC has been shown to protect against stressors such as pollutants released in fires.

“Developing food-based chemoprevention has a lot of implications,” Fujioka says. “It can lead to potentially preventing thousands of cancers, which has a lot of downstream effects on society. And these things can be implemented on a global scale.”

Advancing the work thanks to Masonic support

The University has a long history of researching food as a means to prevent cancer, starting with the work of the late Lee W. Wattenberg, M.D., who spent his career at the University of Minnesota before his death in 2014.

Wattenberg is credited with creating the field of chemoprevention after his landmark paper about the effects of certain compounds on cancer prevention was published in Cancer Research in 1966. Today Fujioka and her colleagues continue this groundbreaking work with support from MInnesota Masonic Charities.

“I love that the Masons see value in my research and in supporting the continuation of a line of research that is highly unique to the University of Minnesota,” Fujioka says. “I'm very humbled and proud to be a part of something that Lee Wattenberg, and now Stephen Hecht, have developed and nourished.”

Fujioka feels fortunate that she’s received Masonic funding for several years, and their generosity is making the phase 1 clinical trial with supplements possible.

“The relief of not having to constantly worry about the financial part of my research has meant a lot,” Fujioka says. “I always feel like I have a tremendous amount of freedom to develop new ideas, and thanks to the Masons, I can obtain data. It’s that generation of preliminary data that drives getting bigger grants, and that’s only possible with their support.”

Lung cancer: by the numbers

  • The deadliest cancer
  • One of the most difficult cancers to treat
  • Primarily caused by smoking, which accounts for 90 percent of cases


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