microbiota
Mika Saarenpää
Indoor gardening iStock.com/s-cphoto
beneficially boosts our microbial exposure
Researchers at the University of Helsinki, Natural Resources Institute Finland and Tampere University have demonstrated that indoor gardening can increase the bacterial diversity of the skin and boost levels of anti-inflammatory molecules in the blood. The results of their research have been published in the journal Environment International.
his research subjects to commit to urban gardening
observed in just one month, but as the research
for one month. The experimental group used a
subjects enjoyed the gardening, many of them
growing medium with high microbial diversity
said they would continue the activity and switch
emulating forest soil, while the control group used
to outdoor gardening in the summer.
a microbially poor peat-based medium.
A
“We don’t yet know how long the changes
“One month of urban indoor gardening
observed in the skin microbiota and anti-
boosted the diversity of bacteria on the skin of the
inflammatory cytokines persist, but if gardening
[experimental] subjects and was associated with
turns into a hobby, it can be assumed that the
higher levels of anti-inflammatory cytokines in the
regulation of the immune system becomes
blood,” Saarenpää said. In contrast, no changes in
increasingly continuous,” Saarenpää said.
the blood or the skin microbiota were seen in the
Saarenpää stated that microbe-mediated
control group. This suggests that peat — the most
immunoregulation can reduce the risk of immune-
widely used growing medium in the world and
mediated diseases or even their symptoms
a large contributor to greenhouse gas emissions
— so if health-promoting microbial exposure
— does not bring any health benefits similar to a
could be increased at the population level, the
medium mimicking diverse forest soil.
healthcare costs associated with these diseases
“We know that urbanisation leads to
could be reduced and quality of life increased.
reduction of microbial exposure, changes in
He said it is particularly important to invest in
the human microbiota and an increase in the
children’s exposure to nature and microbes —
s part of his doctoral thesis, Helsinki’s
risk of immune-mediated diseases,” Saarenpää
as the development of the immune system is at
Mika Saarenpää investigated how microbial
said. “This is the first time we can demonstrate
its most active in childhood — and so suggested
exposure that promotes the health of urban
that meaningful and natural human activity can
introducing planter boxes filled with microbially
residents, particularly enhancing their immune
increase the diversity of the microbiota of healthy
rich soil in kindergartens, schools and hospitals,
regulation, could be increased easily through
adults and, at the same time, contribute to the
especially in densely built urban areas.
meaningful activities integrated into everyday
regulation of the immune system.”
“My research emphasises the dependence of
life. According to Saarenpää, urbanisation has led
Saarenpää’s study shows that microbial
our health on the diversity of nature and that of soil
to a considerable increase in immune-mediated
exposure can be increased easily and safely in
in particular,” he said. “We are one species among
diseases such as allergies, asthma and autoimmune
the home, with only a small amount of space and
others, and our health depends on the range of
diseases, as we live too ‘cleanly’ in cities.
financial investment required. The gardening took
other species. Ideally, urban areas would also have
Knowing from previous studies that contact
place in regular flower boxes, while the plants
such a diverse natural environment that microbial
with nature-derived, microbially rich material can
cultivated, such as peas, beans, mustards and
exposure beneficial to health would not have to
alter the human microbiota, Saarenpää instructed
salads, came from the shop shelf. Changes were
be sought from specifically designed products.”
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