"Culture Shock - Questioning the Efficacy and Safety of Probiotics"
When you make sauerkraut at home,
you don’t have to add any kind of starter bacteria
to get it to ferment,
because the lactic acid producing bacteria
are already present on the cabbage leaves themselves
out in the field.
This suggests raw fruits and vegetables may not
only be a source of prebiotics—fiber—
but also a source of novel probiotics.
Researchers have since worked on characterizing
these bacterial communities and found two interesting things.
First, that the communities on each produce type
were significantly distinct from one another.
So, the tree fruits harbor different bacteria
than veggies on the ground, and grapes and mushrooms seem
to be off in their own little world.
So, if indeed these bugs turn out to be good for us,
that would underscore the importance of eating
not just a greater quantity, but greater variety
of fruits and veggies every day.
And second, they found that there were significant differences
in microbial community composition
between conventional and organic produce.
This highlights the potential for differences
in the bacteria between conventionally and organically
farmed produce items to impact human health;
but, we don’t know in what direction.
They certainly found different bacteria on organic versus conventional,
but we don’t know enough about fruit and veggie bugs
to make a determination as to which
bacterial communities are healthier.
What about probiotic supplements?
I’ve talked about the potential benefits,
but there appears to be publication bias
in the scientific literature about probiotics.
This is something you see a lot with drug companies,
where the sponsor, the supplement company
paying for their own probiotic research,
may not report negative results, not publish it,
as if the study ever happened.
And so, then, we doctors just see the positive studies.
Using fancy statistical techniques, they estimated
that as many as 20 unflattering studies were simply MIA.
And, even in the studies that were published,
even when the authors were directly sponsored by like some yogurt company,
the conflicts of interest were very commonly not reported.
There’s also been concerns about safety.
A review for the government’s Agency for Healthcare Research and Quality concluded
that there’s a lack of assessment and systematic reporting
of adverse events in probiotic intervention studies;
so, while the available evidence in randomized controlled trials
does not indicate an increased risk for the general public,
the current literature is not well equipped
to answer questions on the safety of probiotics with confidence.
This is the study that freaked people out a bit.
Acute pancreatitis, sudden inflammation of the pancreas,
is on the rise, which can become life threatening in some cases,
as bacteria break through our gut barrier
and infect our internal organs.
Antibiotics don’t seem to work, so how about probiotics?
Seemed to work on rats.
If you cause inflammation by cutting them open
and mechanically damaging their pancreas,
not only do probiotics show strong evidence for efficacy,
but there were no indications of harmful effects—
So, half the people with pancreatitis got probiotics,
half got sugar pills, and, within 10 days,
the mortality rates shot up in the probiotics group
compared to placebo.
More than twice as many people died on the probiotics.
Thus, probiotics for acute pancreatitis probably is not a good idea.
But, further, probiotics can no longer
be considered to be just completely harmless.
The researchers were criticized for not telling patients,
not cautioning patients about the risk
before signing up for the study.
(The study subjects were told probiotics had a long history
of safe use with no known side effects).
In response to the criticism, the researchers replied
there were no known side effects—until their study.