Exercise more. Eat well. Make new friends.
As we compile our lists of resolutions to improve physical and mental health in 2023, new research from CU Boulder suggests one addition could have a powerful impact: gardening.
Funded by the American Cancer Society, the first-ever randomized, controlled trial of community gardening found that those who started gardening ate more fiber and did more physical activity; two known ways to reduce the risk of cancer and chronic disease. They also saw their stress and anxiety levels decrease significantly.
The results were published on January 4 in the journal Planetary Health Lancet.
These results provide concrete evidence that community gardening could play an important role in the prevention of cancer, chronic diseases and mental health disorders. »
Jill Litt, senior author, professor in the Department of Environmental Studies at CU Boulder
Filling the research gap
Litt has spent much of his career researching affordable, scalable, and sustainable ways to reduce disease risk, especially in low-income communities.
Gardening seemed like a great place to start.
“No matter where you go, people say there’s 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 hard to get support for new programs, she said.
Some small observational studies have shown that people who garden tend to eat more fruits and vegetables and have a healthy weight. But it’s unclear whether healthy people simply tend to garden or whether gardening influences health.
Only three studies applied the gold standard of scientific research, the randomized controlled trial, to the hobby. None looked specifically at community gardening.
To fill the void, Litt recruited 291 adult non-gardeners, average age 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 assigned to the community gardening group and the other half to a control group who were asked to wait a year to start gardening.
The gardening group received a free community garden plot, seeds and seedlings, and an introductory gardening course through the nonprofit Denver Urban Gardens program and a study partner.
Both groups completed periodic surveys of their nutritional intake and mental health, underwent body measurements and wore activity monitors.
A fiber boost
In the fall, those in the gardening group 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, influencing 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.
“A one-gram increase in fiber can have significant positive health effects,” said co-author James Hebert, director of the University of South Carolina Cancer Prevention and Control Program.
The gardening group also increased their level of physical activity by about 42 minutes per week. Public health agencies recommend at least 150 minutes of physical activity per week, a recommendation met by only a quarter of the US population. With only two to three weekly visits to the community garden, participants achieved 28% of this requirement.
Study participants also saw their levels of stress and anxiety decrease, with those who entered the study most stressed and anxious seeing the greatest reduction in mental health issues.
The study also confirmed that even novice gardeners can reap measurable health benefits from this hobby in their first season. As they get more experience and enjoy better yields, Litt suspects those benefits will increase.
Thriving Relationships
The study results come as no surprise to Linda Appel Lipsius, executive director of Denver Urban Gardens (DUG), a 43-year-old nonprofit that helps about 18,000 people each year grow their own food in community gardens.
“It’s transformational, even life-saving, for so many people,” Lipsius said.
Many DUG participants live in areas where access to affordable fresh fruits and vegetables is otherwise extremely limited. Some are low-income immigrants who now live in apartments; having a garden plot allows them to grow food from their home country and pass down traditional recipes to family and neighbors.
The social bond is also huge.
“Even if you come to 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 the relationships blossom,” Litt said, noting that while 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 in a natural space outdoors with others. »
Litt said she hopes the results will encourage health professionals, policy makers and land planners to turn to community gardens and other spaces that encourage people to gather in nature, as essential part of the public health system. The evidence is clear, she says.
Gardening work.
Researchers from the Colorado School of Public Health, Colorado State University and Michigan State University also contributed to this study.