Lifestyle diseases — depression, diabetes, obesity, stroke, heart disease — have become a major public health problem. The World Health Organization estimates that, around the globe, 350 million people suffer from depression. The International Diabetes Federation estimates that 415 million people suffer from diabetes. These soaring numbers show no signs of abating but, rather, are spiraling upward as more of the world’s people move from rural to urban areas.

But there’s a simple solution: Time spent with nature. No expensive medicines, no elaborate treatments. Just 20 minutes a day walking or sitting in a natural setting lowers stress hormone levels. In a study at the University of Michigan published last month in “Frontiers in Psychology,” researchers measured “salivary biomarkers” — cortisol and amylase in spit.

The so-called “nature pill” helps not just the mind but also the body as stress levels are reduced. As the American Heart Association notes, stress “may affect behaviors and factors that increase heart disease risk: high blood pressure and cholesterol levels, smoking, physical inactivity and overeating.”

We had these thoughts in mind last week as we went to visit the gardens at the Cornell Cooperative Extension on Martin Road in New Scotland. We left the stress of our newsroom, and the never-ending flow of emails, to stroll in the sunshine with the coordinator of the Master Gardeners, Carole Henry.

We listened to her describe the many different kinds of gardens, each plant labeled, to educate and inspire. She greeted the plants like old friends whom she hadn’t seen after a long winter. Henry had a grandmother who propagated roses in the 1930s and a mother who, like herself, was a horticulturist.

We had read that, in the United States, one in three people — a total of  117 million — garden. We believe the other two-thirds should give it a try.

A meta-analysis published three years ago, with researchers from both England and Japan, analyzed a wide range of studies, from the United States, Europe, Asia, and the Middle East, to determine positive effects of gardening on health.

“There are several possible, but not mutually exclusive, pathways through which gardening promotes health,” the researchers write. “The first, and most direct one, is the added health benefits of direct experience with nature.”

Second, gardening encourages people to undertake physical exercise, which improves both physical and psychological health. Third, gardens, especially allotment and community gardens, offer a chance for people to interact with each other, forging and reinforcing social ties, and building a sense of community.

“Fourth, and most indirectly,” the researchers conclude — although, to us, this seems the most direct — “engagement in gardening could ensure people have a healthier diet, rich in fruits and vegetables.”

We wait every year for our former publisher to bring us home-grown rhubarb in the spring, followed by tender green lettuce leaves; and late in the summer, succulent tomatoes; and, finally, come fall, enough zucchini to make breads and stews and soups. All of these are grown from old-fashioned seeds, nothing genetically modified, and without pesticides or other harmful chemicals.

Just thinking about this produce makes our mouth water.

The researchers conclude, “With an increasing demand for reduction of health care costs worldwide, our findings have important policy implications … gardening can improve physical, psychological, and social health, which can, from a long-term perspective, alleviate and prevent various health issues facing today’s society.”

They urge policy-makers to increase people’s opportunities and motivations to garden. So we’re spreading the word in hopes of motivating some of our readers.

We’re pleased to note the town of Guilderland offers space to residents in its community gardens. As more apartment complexes are built in town, the need for space to garden and enjoy nature increases.

Guilderland’s community gardens were established in 1989 in Tawasentha Park, according to coordinator Gerald Hauser. “We’ve grown through the years,” he says, with about 120 garden lots today. Some lots are unspoken for and waiting for gardeners to join the community. The gardeners include people who have come to Guilderland from various parts of the world, adding to the richness.

We’re also pleased that several of our local libraries have started seed libraries, which can inspire patrons to garden.

The World Health Organization defines health as “a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity.”

The Centers of Disease Control and Prevention have supported gardening projects from children needing exercise and healthy food to the elderly who can decrease dementia and combat loneliness through gardening.

The CDC considers gardening a moderate-intensity level activity and says that 2.5 hours weekly can reduce the risk for obesity, high blood pressure, type 2 diabetes, osteoporosis, heart disease, stroke, depression, colon cancer, and premature death.

Cornell Cooperative extension, right here in Albany County, offers support for gardeners in everything from composting for rich soil to raising vegetables for good health. The services are free, with Master Gardeners volunteering their time and expertise.

Carole Henry not only walked us through the gardens on Martin Road for our Home & Garden story last week, she also talked us through the list of nine values outlined by Cornell, to show us how they are carried out here.

Our favorite: “We believe in the power of reflection to help us ‘do less, better.’ In an era of ‘too busy-ness,’ we strive to pause and consider wise action in all our program efforts.”

Henry talked about the physical part of “doing less is better” with this example: “Let’s say with grass: everybody wants to fertilize. But the best way to get rid of crabgrass is to overseed with grass. You don’t have to use chemicals … It’s less harmful to the environment.”

But, in addition to the physical, there is the metaphysical — the relationship between mind and matter. Gardening can center us as well as enrich us. Hyacinth can feed the soul.