While increasing physical activity, eating better, and meeting new people are all excellent habits, new CU Boulder study shows that gardening can have a substantial impact. The first-ever, randomised, controlled trial of community gardening, funded by the American Cancer Society, discovered that people who began gardening ate more fibre and got more physical activity—two recognised strategies to lessen the risk of cancer and chronic illnesses. They also saw a considerable reduction in tension and anxiety. The findings were reported in the Lancet Planetary Health journal.
“These findings provide concrete evidence that community gardening could play an important role in preventing cancer, chronic diseases, and mental health disorders,” said senior author Jill Litt, a professor in the Department of Environmental Studies at CU Boulder.
Filling a research need Litt has devoted most of her career looking for low-cost, scalable, and long-term approaches to minimise illness risk, particularly in low-income populations. Gardening seemed like a good 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 with 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 modest observational studies have discovered that gardeners consume more fruits and vegetables and maintain a better weight. However, it has been unclear whether healthy people just plant more or whether gardening impacts health.
Only three studies have used the randomised controlled trial, the highest standard of scientific research, to investigate the pastime. None have explicitly examined communal gardening.
Litt recruited 291 non-gardening people from the Denver region, with an average age of 41. More than one-third were Hispanic, and more than half were from low-income families. After the final spring frost, half of the participants were assigned to the communal gardening group, while the other half were assigned to a control group that was instructed to wait one year before beginning gardening.
Through the nonprofit Denver Urban Gardens programme and a research partner, the gardening club got a free community garden plot, seeds and seedlings, and an introductory gardening workshop.
Both groups completed surveys about their food consumption and mental health, had their bodies measured, and wore activity trackers on a regular basis.
An increase in fibre
By the autumn, individuals in the gardening group were consuming 1.4 grammes more fibre per day than the control group, a 7% increase. The authors highlight that fibre has a significant impact on inflammatory and immunological responses, impacting everything from how we metabolise food to the health of our gut flora to our susceptibility to diabetes and certain malignancies.
The average adult consumes less than 16 grammes of fibre per day, despite doctors’ recommendations of 25 to 38 grammes.
“An increase of one gramme of fibre can have huge, good benefits on health,” said co-author James Hebert, director of the cancer prevention and control programme at the University of South Carolina. The gardening group also increased their weekly physical activity by roughly 42 minutes. Public health organisations suggest at least 150 minutes of physical exercise each week, which only one-quarter of the US population meets. Participants satisfied 28% of the criteria by visiting the community garden two to three times each week.
Many DUG participants reside in places where access to inexpensive fresh fruits and vegetables is otherwise severely restricted. Some are low-income immigrants who now live in flats; having a garden plot helps them to cultivate food from their native country and pass on traditional recipes to their family and neighbours.
The social link is also enormous.
“Even if you come to the garden looking to grow your food on your own in a quiet place, you start to look at your neighbour’s plot and share techniques and recipes, and over time relationships bloom,” said Litt, noting that while gardening alone is good for you, gardening in the community may have additional benefits. “It’s not just about the fruits and vegetables. It’s also about being in a natural space outdoors together with others.”
Litt said she hopes the findings will encourage health professionals, policymakers and land planners to look to community gardens, and other spaces that encourage people to come together in nature, as a vital part of the public health system. The evidence is clear, she said.