The scientific causes you need to resolve to start out gardening in 2023 | CU Boulder Right now

The scientific causes you need to resolve to start out gardening in 2023 | CU Boulder Right now

get more exercise Eat properly. make new friends.

As we compile our list of resolutions aimed at improving physical and mental health in 2023, new CU Boulder research suggests one supplement could have a powerful impact: gardening.

The first-ever randomized controlled study of community gardening, funded by the American Cancer Society, found that those who began gardening consumed more fiber and exercised more — two well-known ways of increasing their risk of cancer and chronic disease to decrease. They also saw their stress and anxiety levels decrease significantly.

Professor Jill Litt examines a plant in a community garden next to Regis University with colleagues Evan Coringrato, Erin Decker and Angel Villalobos. Photos by Glenn Asakawa/CU Boulder, 2017.

The findings were published Jan. 4 in the journal Lancet Planetary Health.

“These results provide tangible evidence that community gardening may play an important role in preventing cancer, chronic disease and mental disorders,” said lead author Jill Litt, professor in the Department of Environmental Studies at CU Boulder.

Fill in the research gap

Litt has spent much of her career finding affordable, scalable, and sustainable ways to reduce disease risk, particularly in low-income communities.

Gardening seemed like an ideal place to start.

“No matter where you go, people say there’s just something about gardening that makes them feel better,” said Litt, who is also a researcher at the Barcelona Institute for Global Health.

But solid science on its benefits is hard to come by. Without evidence, it’s difficult to get support for new programs, she said.

A few small observational studies have found that people who garden tend to eat more fruits and vegetables and have a healthier weight. However, it was unclear whether healthier people only tend to garden, or whether gardening affects health.

Only three studies have applied the gold standard of scientific research, the randomized controlled trial, to the pastime. None have dealt specifically with community gardeners.

To fill the gap, Litt recruited 291 adult non-gardeners with an average age of 41 from the Denver area. More than a third were Hispanic and more than half came from low-income households.

After the last spring frost, half were allocated to the community gardening group and half to a control group, who were asked to wait a year to start gardening.

The gardening group received a free community garden plot, some seeds and seedlings, and an introductory gardening class through the nonprofit Denver Urban Gardens program and a study partner.

Both groups regularly completed surveys about their dietary intake and mental health, underwent body measurements and wore activity monitors.

It’s not just about fruits and vegetables. It’s also about being together with others in a natural outdoor space.”

A fiber boost

During the fall, the gardeners ate an average of 1.4 grams more fiber per day than the control group — an increase of about 7%.

The authors note that fiber has a profound effect on inflammatory and immune responses, affecting everything from how we metabolize food to the health of our gut microbiome to our susceptibility to diabetes and certain cancers.

While doctors recommend around 25 to 38 grams of fiber per day, the average adult consumes less than 16 grams.

“An extra gram of fiber can have major, positive health effects,” said co-author James Hebert, director of the University of South Carolina’s Cancer Prevention and Control Program.

The gardening group also increased their physical activity by about 42 minutes per week. Public health officials recommend at least 150 minutes of physical activity per week, a recommendation that only a quarter of the US population meets. With just two to three visits to the community garden per week, participants met 28% of this requirement.

Study participants also saw their stress and anxiety levels decrease, with those who came into the study most stressed and anxious seeing the greatest reductions in their mental health problems.

The study also confirmed that even inexperienced gardeners can reap measurable health benefits from the pastime in their first season. As they gain more experience and generate higher yields, Litt suspects these benefits will increase.

Professor Jill Litt speaks with colleagues Erin Decker and Angel Villalobos

Professor Jill Litt speaks with colleagues Erin Decker and Angel Villalobos at a community garden in the Denver area. Photo by Glenn Asakawa/CU Boulder, 2017.

thriving relationships

The study results don’t surprise Linda Appel Lipsius, executive director of Denver Urban Gardens (DUG), a 43-year-old nonprofit that helps about 18,000 people grow their own food in community gardens each year.

“It’s transformative, even life-saving, for so many people,” Lipsius said.

Many DUG participants live in areas where access to affordable fresh fruit and vegetables is otherwise extremely limited. Some are low-income immigrants who now live in apartments – a garden plot allows them to grow food from their home country and pass traditional recipes down to their family and neighbors.

The social bond is also great.

“Even if you come into the garden to grow your own food in a quiet place, you start looking at your neighbor’s plot and sharing techniques and recipes, and over time relationships blossom,” Litt said, noting that he gardening alone is good for you, community gardening can have additional benefits. “It’s not just about fruits and vegetables. It’s also about being together with others in a natural outdoor space.”

Litt said she hopes the findings will encourage health professionals, policymakers and land planners to consider community gardens and other spaces that encourage people to come together in nature as an essential part of the public health system. The evidence is clear, she said.


Researchers from the Colorado School of Public Health, Colorado State University, and Michigan State University also contributed to this study.