"Are Avocados Healthy?"
In my last video about avocados, I described the anti-inflammatory effects
and cholesterol and triglyceride-lowering effects,
but what about that video I did years ago
about the chromosome damaging effects in a petri dish?
That all goes back to 1975, when a pesticide naturally produced
by the avocado tree was discovered,
thought to explain why lactating livestock
suffered mammary gland damage nibbling on the leaves.
The toxin was named persin, also found to be damaging to the heart,
which is why you should never feed avocado to your pet birds.
But hey, if it attacks mammary cells in animals,
might it attack breast cancer cells in humans?
It did seem to have the same kind of cell cytoskeleton clumping effect
in vitro that chemotherapy can have, demonstrating potent cell
growth-stopping and killing effects of the novel plant toxin
among various lines of human breast cancer cells.
So, they’re thinking about how it might one day
be used as chemo itself.
But, here I am thinking “Holy guacamole, Batman,
please tell me it doesn’t have toxic effects on normal cells too.”
In 2010, we got an answer, an evaluation of the genotoxicity,
the toxicity to our chromosomes,
of avocado extracts on human white blood cells in a petri dish.
Normally, less than 10% of our dividing cells
have any chromosome abnormalities,
but drip some avocado fruit extracts on them
and up to half come out defective in some way.
They conclude that there’s something in avocado fruit
that can potentially induce significant genomic instability
and some genetic damage in human white blood cells in a petri dish.
If the same effect occurs in actual people, it could,
for example, result in transforming cells into cancer.
That is a big if, though.
These were blood cells.
You don’t inject guac into the vein.
For anything to get into our bloodstream,
it first has to survive our stomach acid,
get absorbed through our intestines,
and then sneak past our liver’s detoxification enzymes.
And indeed, persin may be affected, changed by acidic conditions.
So, given all the differences between what happens
in a petri dish and a person, it’s essential to carry out
further studies before making a final remark about its toxicity.
Okay but, what do you do before these studies come out?
I was concerned enough that I provisionally moved it
from a stuff-your- face green-light food,
to a moderate-your- intake yellow-light food,
until we knew more, to err on the side of caution.
Even if persin was utterly destroyed by stomach acid,
what about oral cancer?
At high enough concentrations, avocado extracts can harm
the growth of the kinds of cells that line our mouths.
Yeah but, this is in a petri dish, where the avocado
coming in direct contact with the cells,
but that’s kinda what happens in your mouth when you eat it.
But, it harms oral cancer cells even more.
Here’s a bunch of oral cancer cells.
Those red dots are the mitochondria,
the power plants of the cells fueling cancer growth,
extinguished by the avocado extract.
But, since it does this more to cancerous than normal cells,
they end up concluding avocados may end up preventing cancer.
What about the esophagus, which lies between the mouth and the stomach?
They similarly found that an avocado fruit extract
appeared to inhibit cancer cell growth more than normal cell growth,
when it came to colon cancer cells or esophageal cancer cells.
But, rather than comparing the effects
to normal colon and esophagus cells,
they compared them to a type of blood cell,
which again is of limited relevance
in a petri dish study of something you eat.
This study was pretty exciting, though.
It looked at p-cresol, which is a uremic toxin,
may also to toxic to the liver,
has been found associated with autism,
and comes from eating high protein diets,
whereas if you eat a more plant-based diet,
the only source of prebiotics, like fiber and resistant starch,
your levels go down.
See, fermentation of carbohydrates in the colon,
like fiber, is considered beneficial,
whereas fermentation of protein, which is called putrefaction,
is considered detrimental.
So, you switch people to a high protein diet,
and within days, the excess protein putrefying in their gut
leads to an increase in ammonia as well as p-cresol,
in fact, a doubling of levels within a week.
But, might phytonutrient- rich plant foods,
like apples, cranberries, grapes—or avocados,
protect the cells lining our colon
from the deleterious effects of p-cresol
in terms of cell viability, mitochondrial function,
and epithelial integrity,
meaning like protection against gut leakiness?
Here’s that data on barrier function integrity,
damaged by p-cresol, but rescued
by all the cranberry, avocado, grape, and apple extracts,
though mitochondrial function was only improved
by the cranberries and avocados,
and they were also the only ones that appeared to prevent
the deleterious effect of p-cresol on colon cell viability.
But, bottom line, avocados appear to have beneficial effects
on colon lining cells; so, that’s a good sign.
Okay but, enough of these in vitro studies, already.
Yes, an avocado extract can inhibit cancer cell growth
in a petri dish,
but unless you’re doing some unspeakable things
to that avocado—like guacamole with benefits,
there’s no way that the avocado is going to come
in direct contact with your prostate cells;
So, what does this study mean?
That’s why I was so excited to see this study:
the first to actually look for a link
between avocado consumption, actual human beings eating avocados
and prostate cancer.
So, do avocado eaters have more cancer risk
or less cancer risk?
We’ll find out…
right now!
Men who ate the most avocado, more than about a third of an avocado a day,
reduced their risk of prostate cancer:
in fact, less than half the odds.
So, with the data on improved artery function, lower cholesterol,
and, if anything, an association with decreased cancer risk,
I’d suggest moving it back into the green zone.