"Can Vegan Fecal Transplants Lower TMAO Levels?"
Almost 2,500 years ago, Hippocrates stated that
“All disease begins in the gut.”
Feed our gut bacteria right, with whole plant-foods,
and they feed us right back with beneficial compounds
like butyrate, which gut bugs make from fiber.
Feed them wrong, on the other hand, and they can produce
detrimental compounds like TMAO, which our gut bugs
make from cheese, seafood, eggs, and meat.
Now we used to think that TMAO only contributed to
cardiovascular diseases, like heart disease and stroke,
but more recently it has been linked to everything from
psoriatic arthritis to polycystic ovary syndrome.
I’m most concerned about our leading killers, though.
If you look at the top ten causes of death in the United States,
we know about heart disease and stroke, killers #1 and #5,
but recently, an association has been between blood levels
of TMAO and the risks of various cancers, killer #2.
It could be the inflammation caused by TMAO that explains
the link between TMAO and cancer, but it could also be
oxidative stress such as free radicals, DNA damage,
or a disruption in protein folding.
Killer #4 are chronic obstructive pulmonary diseases
like emphysema, and TMAO is associated with premature death
in patients with exacerbated COPD,
though they suspect it’s just due to them dying
from more cardiovascular disease.
The link to stroke is a no-brainer—no pun intended—
because of the higher blood pressure associated
with higher TMAO levels as well as the greater likelihood
of clot formation in those with atrial fibrillation.
And those with higher TMAO levels also appear to have
worse strokes and four times the odds of death.
Killer #6 is Alzheimer’s disease.
Does TMAO even get up into the brain?
Yes, TMAO is present in human cerebrospinal fluid,
which bathes the brain, and indeed the levels are higher
in both those with mild cognitive dysfunction
and those with Alzheimer’s disease dementia.
In the brain, TMAO has been shown to induce neuronal senescence
(meaning deterioration with age), increased oxidative stress
and impaired mitochondrial function, all of which may contribute
to brain aging and cognitive impairment.
Killer #7 is diabetes, and people with higher TMAO levels
are approximately 50% more likely to have diabetes too.
Killer #8 is pneumonia, and TMAO predicts fatal outcomes
in pneumonia patients even without evident heart disease.
Killer #9 is kidney disease, and TMAO is strongly related
to kidney function and predicts fatal outcomes there as well.
Over a period of five years, more than a half of chronic kidney
disease patients who started out with an average or higher
TMAO levels were dead, whereas among those in the
lowest third of levels, nearly 90% remain alive.
Okay, so how can we lower the TMAO levels in our blood?
Because TMAO originates from dietary sources, we could limit
our intake of choline and carnitine-rich foods,
but they’re "so widespread", we’re talkin’ meat, eggs, and dairy.
Therefore, restriction of foods rich in TMAO-creating nutrients
may not be practical. I mean, can’t we just get
a vegan fecal transplant?
Vegan donors were kind enough to provide
the investigators with a fresh morning sample.
If you remember, if you give a vegan a steak,
despite all the carnitine in the meat, they make almost no TMAO
compared to a meat-eater, presumably because they haven’t been
fostering steak-eating bugs in their gut.
Remarkably, even if you give plant-based eaters the equivalent
of a 20-ounce steak every day for two months,
only about half start ramping up production of TMAO
showing just how far their gut flora had to change.
The capacity of veggie feces to churn out TMAO is almost nonexistent.
So, instead of eating healthier, why not just get
some of that sweet vegan poop off the brown market.
In a double-blind, randomized, controlled trial,
research subjects either got vegan poop or their own poop back.
The complete stool production was stirred—not shaken—
and then infused through a hose down their nose,
and . . . it didn’t work.
First of all, the vegans they recruited for their study
started out making TMAO themselves, as opposed to the other study
where they didn’t make any at all.
This may be because the other study required the vegans
to have been plant-based for at least a year, and this study didn’t.
So yeah, not much of a change in TMAO running through their bodies
two weeks after getting the vegan poop, but the vegan poop they got
seemed to start out with some capacity to produce TMAO in the first place.
So, the failure to improve after the vegan fecal transplant
could be related to limited baseline microbiome differences
as well as the continuation of an omnivorous diet after the transplant.
What’s the point of trying to reset your microbiome
if you’re just going to eat meat?
Well, the researchers didn’t want to switch people
to a plant-based diet since they knew that alone can change
your microbiome, and they didn’t want to introduce any extra factors.
Bottom line—no pun intended—
it looks like there may not be any shortcuts.
We may just have to eat a healthier diet.