Dr Michael Mosley on the benefits of gardening

On his BBC Radio 4 podcast ‘Just One Thing’, Dr. Michael Mosley explains that gardening is not only good for physical fitness but benefits the brain, mood and gut microbiome.

Dr Michael Mosley

Mosley’s podcast looks at doing the one thing that could help improve our health and wellbeing, when time is tight. Mosley is a science presenter, journalist and executive producer, best known for his books on the fast diet.

According to Mosley, gardening provides a wide range of direct, physical health benefits, such as provision of exercise, gets you into the fresh air, muscle build and reducing the risk of Type 2 diabetes. “A recent study of 140,000 Americans, aged 65 and older, found that the gardeners were significantly less likely to have Type 2 diabetes than people who engaged in other forms of exercise”, explained Mosley.

“As well as being good for your body, gardening is also good for your brain and you don’t need to spend hours in the garden to reap the benefits. In one small study, just 20 minutes of tending to a small vegetable patch led to an increase in levels of BDNF – Brain-derived neurotrophic factor. This is a hormone that has been shown to improve learning and memory. That’s because, appropriately enough, it acts like fertiliser for your brain cells helping them stay in good shape. The same study also found that gardening increased levels of another important protein, VEGF – Vascular endothelial growth factor, which amongst other things, boosts the supply of blood to brain cells”, he added.

He went on to explain, that there may even more “stranger” things going on than direct physical benefits. Mosley explains that when we garden, we are in actual fact infecting ourselves with beneficial bacteria, commonly found in soil. “For example, when lab mice were expose to a soil bacterium – Mycobacterium vaccae, their levels of the feel good hormone serotonin increased. The Mycobacterium vaccae appear to have activated neurons in areas of the brain that play an important role in coping with stress.”

Mosley talked about a study that found that airborne bacteria, in soil dust can not only make their way into gut microbiome of mice but when they get there they produce butyrate – a short chain fatty acid, key to keeping the gut barrier healthy.

Talking to Dr Hannah Holscher from the University of Illinois Urbana-Champaign about the impact on our microbiome, she explained that their research detected that some microbes found in soil were also found within their microbiome samples of their research sample – gardening families. Furthermore, the research detected greater diversity within their microbiota within the gardening families. For the study, they recruited families that gardened and families that didn’t, asking them to complete dietary questionnaires and provide stool samples before the gardening started (late April) and again during peak gardening harvest time (August).

Holscher explained: “We also collected soil samples from the gardening sites during the same time periods. What we found was that gardening families reported more dietary fibre intake. They also had greater microbiome diversity and more bacteria which can break down dietary fibre within their intestinal tracks.

When asked how the microbes find their way into our gut, Holscher explained that if someone eats carrots or potatoes which have had direct contact with the soil, even if they wash it there will still be some residual microbes on those foods.

Though relatively novel, the concept of gardening having a positive impact on our microbiome is becoming more prominent. The Ethnobotanist and designer, Sid Hill who runs an ecological design & landscape studio based in St Ives Cornwall creates vibrant micro-habitats in his designs, which according to Hill not only support nature but have a positive effect on our microbiome, where the environment acts like a probiotic to humans. One of the show gardens at the upcoming RHS Chelsea Flower Show, explores the connection between the health of the soil, wildlife and our microbiome. Designed by Chris Hull and Sid Hill, the Bowel Research UK Microbiome Garden focuses on health, for people, plants and all life, taking inspiration from human cultures that tended thriving ecosystems for nourishment.

Mosley concluded the podcast by saying: “I’m delighted to hear that getting grubby in the garden can help our overall health. It’s good to know that gardening is not only a good form of exercise but I could potentially be boosting my gut bacteria and improving my overall health as well.”