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during our lifetime through
the Massive Open Online Course
(MOOC) Nutrition and Health
Human Microbiome, led by Belzer.
Gary D. Wu (Philadelphia, USA)
noted that in characterizing the
interactions between diet and the
human gut microbiome, animal models
are a great tool for uncovering cause-
and-effect relationships.
However, while diet has an extreme
and consistent effect on the gut
microbiota of mice, smaller effects
have been observed in humans.

immune regulation was also altered,
which points to the impact of a low-
fiber diet not only on gut microbial
communities but also on systemic
health. These preliminary results
need to be confirmed in humans and
the main learnings of this data for
humans is that eating lots of fiber
from diverse natural sources should
be encouraged in order to avoid our
gut commensal microbes depending
more on mucus rather than fiber as
a substrate.

“Interactions between
diet, gut microbiota and
the immune system will
Wu explained the current challenges lack of dietary fiber have an increased depict a clear picture of the
of characterizing the relationship abundance of mucus-degrading bacteria, underlying mechanisms by
between diet and gut microbiota in including Akkermansia muciniphila and which dietary fiber impacts
the context of inflammatory bowel Bacteroides caccae. the gut microbiota and
disease (IBD). How response to influences disease risk.”
dietary therapy works in IBD is still As a result, host susceptibility to
unknown and engineering the gut enteric pathogens increased and Mahesh Desai
environment may help improve
current IBD therapies that focus
on targeting the microbiome and
its metabolome beyond current
treatments focused on the immune
suppression of the host.
When looking specifically at the
impact of diet on gut microbial
communities and the gut environment,

Mahesh Desai from the Luxembourg
Institute of Health noted that human
fiber consumption has dramatically
decreased in recent decades, going
from 150g of fiber a day to the
current average of 10g. Desai’s work
focused on how a fiber-deprived gut
microbiota leads to an increase in Mahesh Desai during his lecture “Dietary fibre and the mucus barrier”.
the proliferation of mucus-degrading
species and a decrease in fiber-
degrading bacteria, together with an
altered host immune regulation, which
means that in the context of a fiber-
free diet, gut commensal bacteria
use mucus as an alternative nutrient.
Desai described his mouse study on
fiber, which showed that mice with a

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