The gut microbiota is a huge topic and has some very significant implications for health and nutrition. Here I’ve explained just a tiny bit of the research.
After five years of investigation, the EU project ‘MyNewGut’ – made
up of thirty organisations from 15 countries – has released its
scientific results on the role played by the gut microbiota on physical
and mental health.
On of the group’s key findings is that Western diets rich rich
in saturated fat result not only in obesity, but also in
depression-like behaviour. Consequently, the MyNewGut partners says that
people with depression or vulnerability to depression should be
encouraged to eat plant-based diets with higher levels of grains, fibres
and fish.
The research findings were presented during a project-concluding conference
last month, and is likely play a key role in the future development of
more effective interventions targeting the gut — fighting obesity,
metabolic syndrome, and behavioural disorders, like eating and emotional
disorders.
Key findings include:
Bacterial strains in our gut could be the next generation of probiotics
Consuming an excess of proteins generates some toxic metabolites
Diets rich in fibres are associated with fewer symptoms of
depression, help to maintain body weight and reduce the risk of
developing chronic metabolic diseases
A high fat diet may have a negative impact on the gut microbiota and the brain
The gut microbiota influences metabolic health
New gut bacteria may help fight obesity and mental disorders The MyNewGut project has discovered new bacterial species and
strains in healthy people that seem to be effective against obesity,
metabolic and mental disorders related to stress and obesity (for
example, depression). They do so by influencing the endocrine and immune
pathways that have an impact on both our physical and mental health.
The bacterial strain ‘Bacteroides uniformis CECT 7771’ has shown
pre-clinical efficacy on metabolic and immune dysfunctions in obesity,
for example reducing serum triglyceride levels, glucose intolerance and
body weight gain as well as inflammation.
Bifidobacterium pseudocatenulatum CECT 7765 was shown to reduce
depressive-like behaviour associated with obesity in pre-clinical
trials. A Bifidobacterium longum strain has been demonstrated to have a
positive impact on perceived stress, sleep quality and cortisol release
in a double-blinded placebo-controlled intervention trial in humans.
These strains could potentially be next generation probiotics that
could in the future be used to help tackle obesity and depression.
How diet has an influence on the gut microbiota Diet appears to be a major factor that influences the composition of
the human gut microbiota. MyNewGut experts have conducted several human
intervention trials to investigate dietary health effects potentially
mediated by the microbiota and they are publishing a range of position
papers that will show evidence on how we could inform future dietary
recommendations.
MyNewGut partners looked specifically into the role played by
proteins, fats and fibres on the gut microbiota. They found that high
intake of proteins or a high fat diet may harm the gut microbiota.
They also discovered that high protein consumption, which increases
protein fermentation in the large intestine, generates some of the toxic
metabolites (products of metabolism) linked to diseases such as
colorectal cancer.
A high fat diet, especially when rich in saturated fatty acids may
have negative effects on the gut microbiota, characterised by a lower
number of microbes and a lower variety of microbial species. High-fat
diets rich in omega 3 or omega 6 polyunsaturated fatty acids do not seem
to negatively affect the microbiota, whereas the effects of
monounsaturated fatty acids are less consistent.
High fat diets are associated with depression Studies of the MyNewGut partners showed that Western diets rich in
saturated fat resulted not only in obesity, but also in depression-like
behaviour. The depression-like behaviour associated with diet-induced
obesity depended on the gut microbiome, because the effects were blunted
by antibiotic-treatment. In high-fat diet fed mice, using the same
mouse model, MyNewGut also reported that a bacterial strain
(Bifidobacterium pseudocatenulatum CECT 7765) reduces depressive-like
behaviour associated with obesity, acting through the gut-brain axis.
The teams stress that results are only a starting point, and new
research would have to confirm the findings in humans.
The role of the gut in metabolic health Studies in animal models conducted by project partners have revealed
new mechanisms whereby the microbiota could impact metabolic health.
Here, MyNewGut partners showed that peptidase activity (DPPIV)
responsible for the degradation of enteroendocrine hormones produced in
the gut, which regulate appetite and glucose homeostasis (like
glucagon-like peptide I [GLP-I]), are of bacterial origin.
This means that the presence of specific bacteria producing these new
enzymes can adversely influence appetite, food intake and body weight
gain.
Gut microbiota: we are all different The MyNewGut project has also explored innovative interventions,
including Faecal Microbiota Transplants (FMT) for restoring
dysbiosis-associated disorders. In FMT, the microbiota of a healthy
donor is transferred to an individual suffering from some form of
dysbiosis.
In MyNewGut studies, the donor’s microbiota was transferred to human
subjects with metabolic syndrome. In these studies, the responsiveness
to treatment depended on the individual’s gut microbiota profile,
suggesting a need for personalised intervention strategies.
This study demonstrates that the individual’s microbiota directly
impacts neural systems that could mediate the impact of food intake on
metabolic health.
The impact of early life microbial imbalance on health MyNewGut partners investigated whether effects of environmental
factors in early life and childhood also impact health outcomes in later
stages of life in humans. For example, they conducted a longitudinal
study in children to determine the role of the microbiota, the lifestyle
(diet, exercise, etc.) and other individual factors (immune and
metabolic profile) in the development of overweight.
The study revealed that specific microbiota configurations were
indeed correlated to inflammatory markers and dietary patterns, and
subsequently to the development of obesity.
MyNewGut has also discovered that dietary changes which favourably influence the microbiota may have a higher and longer-lasting effect during stages of development, and this emphasises the importance of diet during early life for long-term health in adulthood.
REMEMBER the last time you had a stomach bug and just wanted to crawl into bed and pull up the covers? That is called “sickness behaviour” and it is a kind of short-term depression. The bacteria infecting you aren’t just making you feel nauseous, they are controlling your mood too. It sounds absurd: they are in your gut and your feelings are generated in your brain. In fact, this is just an inkling of the power that microbes have over our emotions.
In recent years, such organisms in the gut have been implicated in a range of conditions that affect mood, especially depression and anxiety. The good news is that bacteria don’t just make you feel low; the right ones can also improve your mood. That has an intriguing implication: one day we may be able to manipulate the microbes living within our gut to change our mood and feelings.
It is early days, but the promise is astounding. The World Health Organization rates depression and anxiety as the number one cause of disability, affecting at least 300 million people worldwide. The new findings challenge the whole paradigm of mental illness being caused by a chemical imbalance in the brain, and offer an alternative to drug treatment. You’ve probably heard of probiotics, but these are their new incarnation – psychobiotics. They could be about to change the mood of the planet.
After eating with the Hadza for just three days, Spector — who already had very healthy/diverse gut flora for a civilized person — increased his microbe diversity by 20 percent, an astonishing improvement. Not surprisingly, his gut flora balance returned to what it was before when he returned home.
