This is going to be a bit controversial but it has some
really important lessons. You may have heard the fact that
bacteria and probiotics are the essence of life.
Without them, you would die pretty early in life. Here's what I
The body is made up of approximately
10 trillion human cells and
100 trillion bacterial cells. So technically in that
capacity, you are 90% bacteria. There are actually more
bacterial cells in your body than there are stars in our
With that in mind, you can probably understand why
having healthy bacterial flora is extremely important for
your overall longevity.
I want to show you a controversial study that I learned about
while studying neuroscience at Duke. It was done by a
neuroscientist named John Cryan of University College Cork in
He was curious to test the stress response of mice when
put into certain situations when fed a certain bacteria. So he
took two groups of mice. The first group was fed a probiotic
strain known as lactobacillus rhamnosus. The second
group, which was his control group, didn’t receive any probiotic
Cryan hypothesized that the
lactobacillus rhamnosus would help with a stress
He threw both groups into buckets of water and
measured their latency to give up. There was no
way for either group to get out of the bucket.
The control group, who didn't have any probiotics,
would give up. Their stress response was so
high that they would swim around in circles and simply give up
after four minutes. Cryan would pluck them out of the water
before actually drowning. He didn't let them die.
On the other hand, the group that he fed the
lactobacillus rhamnosus to
would not stop swimming.
They just would not give up. While the control group was
ready to die at a certain point, the
lactobacillus rhamnosus group simply did not give up.
They would just keep on swimming.
Afterwards he measured the cortisol levels of both groups.
He found that the control group actually had
100 times higher cortisol levels than the group
that was fed lactobacillus rhamnosus. The latter were
the ones who didn't give up.
They were the ones who actually had such a low stress response
they had more energy and a will to live. Now
this is where things get more controversial.
Cryan wanted to really test this theory that
lactobacillus rhamnosus is what caused the drastically
lower cortisol levels.
He severed the vagus nerve of the group of mice that took the
lactobacillus rhamnosus then he replicated the same
experiment. He threw both groups of mice back into the water.
What happened next was that both groups acted the
They gave up after minutes of swimming.
What this taught us is that
there is communication between the gut and brain that lowers
cortisol levels with this one strain of bacteria.
While this was done in mice,
humans have the same body structures as these
mice did and we have the same vagus nerve.
We have the GABA receptors in our brain communicate with our
gut with this strain of bacteria.
So it does point to the fact that humans may have a similar
You're probably wondering the same thing as I did the first time
I saw these studies.
Where can I get probiotics? What's the best way to get the
right bacteria, specifically the strains of bacteria that are
great for men? How can I implement this into my diet or