Microbes
are hot on the scientific agenda. In May, the US government launched a National
Microbiome Initiative with an overall budget of half a billion dollars, while
the EU is funding more than 300 projects related to the microbiome. MyNewGut is the largest EU program,
with 30 partners in 15 countries.
The director is Yolanda Sanz at the Spanish National Research Council in
Valencia. Much of this article is
based on her perspectives.
“Our intestine hosts a
complex ecosystem of bacteria; we call it the gut microbiota, which includes at
least 1000 difference species. We get most of our gut microbes soon after
birth, although there is evidence of colonization even during prenatal life.
Over the first 2-3 years
of life, the microbiota is very unstable in its composition. This condition
overlaps with a period in which the immune system is still immature. At this
stage, the microbiota is greatly influenced by diet, for example whether you
are breastfed or not. When an
adult diet takes over, the composition of the gut microbiota becomes more
stable and a microbiotic profile emerges. This usually prevails until old age
when the diet goes back to being less diverse and more unstable, such as in
babies. In some way, the evolution of microbiota reflects our growth and
senescence.” My comment here – keep your diet
diverse, in terms of vegetables, fruits, nuts and whole grains as you age. If you are eating less, make every bite
count.
“Each person has a
different proportion of bacterial species and strains in his or her gut. If I
had to put a figure on it, I would say that about a quarter of the microbiota
is unique to each individual, but it's difficult to give a precise estimate.
Also, we know that our genome influences our gut flora. We don't know how it
works, but at least some features of our microbiota are associated with our
DNA.
If you alter your diet
dramatically, for instance by changing the proportion of fibres, proteins or
fats, you will see relatively quick changes in your microbiota. About 30-40
percent of the bacterial strains will vary in
their abundance. Drugs can also alter the microbiota. Recent studies point to
antibiotics, of course, but also to proton pump inhibitors, anti-inflammatory
drugs and other classes of medications that do not interact directly with
bacteria.
There is growing evidence
of a microbial gut-brain axis in which bacteria can influence the brain, and
vice versa. We know that some strains of intestinal bacteria produce compounds
that have an effect on the nervous system: neurotransmitters, for example, or
metabolites that alter the blood-brain barrier (a barrier which filters the
molecules passing from the body to the brain circulation). We don't yet know
the precise mechanisms, but it's quite clear that the gut microbes can
influence mood and the behavioural patterns. Most of the information comes from
animal studies, but some data in humans are quite conclusive. People with
primary depression, for example, show alterations in the microbiota.
Transplanting the microbiota of depressed patients into mice can replicate the
pathology in the animals.
There have been a few
trials where patients with depression have been given probiotic treatments. The
results are encouraging, but they are small studies, and there are many steps
before we can say whether or not these interventions actually work.
To date, we found many
correlations between the gut microbiota and pathologies: to move towards
therapy we need to establish a causal relationship, and look closely at the
mechanisms by which bacteria interact with the nervous system.”
While
waiting for further data and advice from researchers, it’s a good idea to turn
to a diet that helps the healthy bacteria in your gut, and see whether your
mood can be affected positively.
Remember, your gut bacteria thrive on the fiber from vegetables and
fruit, and a diet high in sugars and refined flour cause them to eat the mucus
layer lining your intestinal tract, leading to a ‘leaky gut’ and inflammation. Use your brain to help your gut – it
can go both ways!
Researchers
at the University of Melbourne published on Omega 3 fish oil in The American
Journal of Psychiatry in 2016: "The strongest finding from our review
was that Omega 3 fish oil -- in combination with antidepressants -- had a
statistically significant effect over a placebo. Many studies have shown Omega
3s are very good for general brain health and improving mood, but this is the
first analysis of studies that looks at using them in combination with
antidepressant medication. The difference for patients taking both antidepressants
and Omega 3, compared to a placebo, was highly significant. This is an exciting
finding because here we have a safe, evidence-based approach that could be
considered a mainstream treatment."
Sadja Greenwood, MD, MPH
Happy New Year, 2017
Quoting Ananda’s song: May
you never, never, never be blue
I know – the country is in
for hard times. Stay strong and
resist. s