"Dietary Sources of the “Longevity Vitamin” Ergothioneine"
Of more than a hundred compounds
measured in the bloodstreams of thousands of individuals,
the one most associated with the lowest rates of disease and death
was ergothioneine.
Higher blood levels were associated with lower risk
of heart disease, stroke, and death
from all causes put together over a period of more than 20 years.
Ergothioneine is an unusual amino acid.
Although it was discovered more than a century ago,
it was ignored until recently, when researchers found
that humans have a highly specific transporter protein in our bodies
specifically designed to pull ergothioneine out of food and into body tissue.
It’s even upregulated right before meal times.
This suggests that ergothioneine plays an important physiological role.
But what? Our first clue was the tissue distribution.
Ergothioneine concentrates in parts of your body
where there are lots of free radicals— the lens of your eye and your liver,
for example, as well as sensitive tissues such as bone marrow and semen.
Researchers found it acts as a cytoprotectant—a cell protector.
Depriving human cells of ergothioneine
leads to accelerated DNA damage and cell death.
Because we can only get it in food,
and there’s toxicity associated with its depletion,
Johns Hopkins University researchers concluded
that ergothioneine “may represent a new vitamin.”
If it were classified as such, that would make it the first new vitamin
since the last new vitamin, B12, was isolated back in 1948.
However, traditional vitamins are characterized
by the manifestation of an overt dietary deficiency disease
within a short time frame, and no specific deficiency disease
has yet been identified.
But perhaps deﬁciency diseases are staring us in the face.
Low blood levels of ergothioneine are correlated with increased risk
of frailty, cardiovascular disease, cognitive impairment,
dementia, and Parkinson’s disease.
To describe nutrients that may not necessarily be essential for life
but may be essential for long-term health,
the famous biochemist Bruce Ames coined the term “longevity vitamin”
and identified ergothioneine as a putative candidate.
What are the best dietary sources?
It’s not made by plants or animals;
only fungi like mushrooms and certain soil bacteria.
Plants can suck some up from the soil, and animals who eat the plants
can similarly benefit, but the highest levels by far
have been reported in mushrooms.
Excessive tillage of the soil,
which is a common practice in modern agriculture,
can disrupt the mycelial network, the fungi filaments
that pass ergothioneine along to the roots of crops,
leaving mushrooms and tempeh— a fungi-fermented soybean cake—
as the only concentrated dietary sources.
This is on a dry weight basis, though, and mushrooms are like 90 percent water;
so, if you change this to prepared wet weight,
tempeh does even better on more of a per serving basis.
As mushrooms go, shiitake may have comparable levels to oyster mushrooms,
about five times more than white button mushrooms,
but may also be five times as expensive— unless you grow your own.
Oyster mushrooms can grow in less than two weeks
with just-add-water kits.
Here’s a pic from my own personal stash.
Porcinis may lead the pack, though,
which could explain why Italians average more than four times
the average ergothioneine intake of Americans.
But even just eating a cup a day of plain white button mushrooms
can double ergothioneine concentrations in the blood.
Yes, ergothioneine is associated with reduced mortality,
but it was also the blood metabolite most strongly connected
to a “health conscious food pattern;”
so, it could just have just been a proxy for healthier eating.
And look, correlation doesn’t mean causation.
Instead of low ergothioneine levels leading to disease,
maybe disease somehow leads to lower ergothioneine levels?
What evidence do we have that we should go out of our way to eat mushrooms?
Well, mushrooms can reduce atherosclerosis in butterfat-fed mice,
and fruit flies fed a 1 percent oyster mushroom diet
did show a slight but significant survival advantage.
And we suspect it’s the ergothioneine, since you can give it straight
and still get a life-extension eﬀect.
But what evidence do we have in people?
Well, mushroom consumption is associated with a lower risk of cancer,
driven mainly by lower breast cancer rates,
and mushroom consumption is associated with a lower risk
of dying prematurely from all causes put together.
I have covered interventional trials showing, for example,
that eating just a few mushrooms a day can improve immune function,
but ergothioneine may be an underrecognized dietary micronutrient
for healthy aging in other ways as well.
Dietary ergothioneine is known to cross the blood-brain barrier,
since it can be found in human cerebrospinal fluid
and post-mortem brain samples.
Perhaps this is why a study in Singapore found that those who consumed
more than two servings of mushrooms a week
had less than half the odds of suffering from mild cognitive impairment,
compared to less than once a week.
And a study of more than 10,000 Japanese elders
found that three or more times a week mushroom eaters
had a significantly lower risk of developing dementia
over a period of about six years.
With cross-sectional studies correlating mushroom consumption
with better brain function, researchers decided to put it to the test
using lion’s mane mushroom, which is especially popular
in traditional Chinese medicine.
Randomized double-blind, placebo-controlled trials on people
with normal cognitive function, on people with mild cognitive impairment,
and on those with early-stage Alzheimer’s disease
did find small cognitive or functional improvements after months
of a third to a full teaspoon of powdered lion’s mane mushroom a day
compared to placebo.
Interestingly, blood ergothioneine levels appear to decline after about age 60,
and this decline is tied to both cognitive decline and frailty.
And this does not appear to be due to declining mushroom intake with age;
so, perhaps the function of the ergothioneine transporter
at the blood-brain barrier declines with age,
potentially making mushroom intake all the more beneficial as we grow older.
So, if I was to create a Dr. Greger’s Baker’s Dozen,
I would probably add mushrooms to the list.