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Happy Bacteria in the Garden
by Dorothy Dobbie
by Dorothy Dobbie

The Local Gardener magazines, Ontario Gardener, Manitoba Gardener and Alberta Gardener, are published by Pegasus Publications Inc.

Drawing on her 30 years' experience as a senior executive in the magazine publishing industry, Dorothy launched Manitoba Gardener in 1998, initially running the business out of her home. Two years later, Dorothy's daughter Shauna, living in Ontario, jumped into the fray with Ontario Gardener. And two years after that, they started Alberta Gardener. Visit us at and register for our "Ten Neat things" newsletter. Watch Shaw TV for garden tips and Listen to CJOB for the Gardener Sundays at 9:08

July 15, 2012

Mycobacterium vacca. released when you garden, works to save an amino acid which is an essential part of the serotonin produced by our bodies. The drug seratonin is important in reducing stress and thus enabling individuals to enjoy happiness and well-being.

Have you even noticed that gardeners, as a group, seem to be pretty happy people? Not only that, but they also seem to keep the cognitive abilities intact into very old age. There may be two very good reasons for these conditions: the first has to do with happy bacteria in the soil and the second with the kind of exercise gardeners do.

Happy bacteria

We’ve all heard the saying, “You have to eat a peck of dirt before you die”, and it seems to be truer than we might have imagined. Researchers have discovered that a particular bacterium found in soil, Mycobacterium vaccae, has the ability to trigger the release of seratonin. Seratonin is the neurotransmitter believed to be responsible for happiness and well being.

Gardeners, when they are digging in the soil, breathe in this happy bacteria or may absorb it through small abrasions on their skin. And a little goes a long way. Researchers who injected mice with the bacteria at the University of Bristol noticed that the positive effects lasted for up the three weeks.

Mary Obrien, an oncologist at Royal Marsden Hospital, London, England, was the first to make the connection. She was inoculating lung cancer patients with M. vaccae to see if it had any effect. What resulted was a reduction in the cancer symptoms plus better emotional health, vitality and even better cognitive functioning.

When Dr. Chris Lowry at Bristol University saw this, it triggered an hypotheses, based on his understanding that the body’s immune response to bacteria can cause the brain to produce serotonin. He conducted a series of experiments on mice and showed that indeed M. vaccae lowered stress, increased their activity and vitality and helped their concentration.

Stress is a villain

It appears that stress can affect gut bacteria and the immune system by activating an enzyme that steals tryptophan, one of the building blocks of serotonin and melatonin. Stress can cause the tryptophan to be converted to a chemical that excites glutamate, which triggers depression, anxiety and memory loss. The Mycobacterium vaccae released in gardening, in contrast, works to save the tryptophan needed to produce serotonin, which reduces stress and lets gardeners enjoy happiness and well-being.

Stress also increased levels of “bad” bacteria such as Clostridium difficile which causes bacteria, especially after antibiotic use. On the plus side, ‘good bacteria” such as those found in live yoghurt help strengthen the immune system and can destroy hostile microorganisms. Lactobacillis acidophilus and Bifido bacterium found in probiotics may be able to combat the effects of C. difficile. There are also studies being conducted as to how diet can impact on depression, OCD, and anxiety.

This doesn’t mean you should start eating mud pies, but do get out into the garden and breathe deeply! Resistance training staves off dementia It has long been noted that being physically active can help stave off dementia and the credit has been given to the increase of blood flow through the brain. But now researchers are saying that exercise, especially strength building exercise, may be even more beneficial that at first thought.

The study by researchers at the Centre for Hip Health and Mobility at Vancouver Coastal Health and the University of British Columbia involved 86 senior women with mild cognitive impairment over a period of six months. Both aerobic and resistance training were looked at, but it was resistance training that showed significant improvements to a whole list of cognitive abilities. The type of training recommended is very similar to what gardeners do as a matter of course: lifting, squatting, doing lunges are all recommended. Their effect on cognitive function is being attributed to “growth factors” which improve the brain.

It’s not a bad idea to follow a resistance training exercise all year round, even for gardeners just to keep in shape for the joys of spring and summer. You can watch a video showing the simple exercises you can do at home or at the gym by going to

Other benefits of Mycobacterium vaccae Links have been drawn and studies are being conducted on a number of conditions that might be alleviated by a better understanding or Mycobacteria vaccae, including: Asthma

Crohn’s and other bowel diseases

Rheumatoid arthritis



Atopic dermatitis




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