Let’s say you really need to find reliable information
about the best diet for high blood pressure,
or heart disease, or diabetes.
Where do you go?
Do you go to a website sponsored by Big Pharma
that wants to sell you pills to fix your problem?
Or, do you want to treat the cause?
Welcome to the Nutrition Facts Podcast
with the latest peer- reviewed research
on the best ways to eat healthy and live longer.
They don’t sell this kind of meth in a back alley.
In today’s story, we look at the ill effects
of an excess of methionine, an amino acid that can cause
cancerous tumors to grow and our lifespan to shrink.
This recent review, noting that vegan diets,
in part because they tend to be naturally low in methionine,
may prove to be a useful nutritional strategy
in cancer growth control,
also looked at methionine restriction and life-span extension.
It seems that the less methionine there is in body tissues,
the longer different animals tend to live.
But what are the possible implications for humans?
I've talked before about the free radical theory of aging,
this concept that aging can be thought of
as the oxidation of our bodies
just like rust is the oxidation of metal,
and methionine is thought to have a "pro-oxidant effect."
So the thinking is that lower methionine intake
leads to less free radical production—
the so-called reactive oxygen species,
which slows the rate of DNA damage,
which then would slow the rate of DNA mutation,
slowing the rate of aging and disease,
thereby potentially increasing our lifespan.
There are three ways to lower methionine intake,
caloric restriction—they call it dietary restriction here,
meaning like you cut your intake of food in half,
for example only eating every other day.
That would lower your methionine intake...
Or, because methionine is found
concentrated in certain proteins,
you could practice protein restriction across the board,
eating a relatively protein deficient diet.
Or the third option is to eat enough food,
eat enough protein, but just eat plant protein,
because they are relatively low in methionine.
Caloric restriction is hard,
because you walk around starving all the time.
Something like every-other-day eating
is never likely to gain much popularity
as a pro-longevity strategy for humans,
so it may be more feasible
to achieve moderate methionine restriction,
in light of the fact that plant-based diets
tend to be relatively low in this amino acid.
As we've seen, plant products tend to be lower
in methionine than animal products.
Yes, protein restriction across the board
can be performed to avoid the hunger of caloric restriction,
but again, methionine restriction could also be performed
emphasizing low-methionine, high quality
vegetable sources of protein.
Among foods containing plant proteins,
legumes are especially rich in essential amino acids,
offering excellent substitutes for proteins of animal origin.
The fact that beans have comparatively low methionine
has been classically considered a disadvantage.
But given the capacity of methionine restriction
to decrease the rate of free radical generation
in internal organs,
to lower markers of chronic disease,
and to increase maximum longevity
ironically converts such a “disadvantage” into a strong advantage
and fits well with the important role of beans
in healthy diets like the traditional Mediterranean diet.
Interestingly, soy protein is also especially poor in methionine,
and it is widely considered that soy-containing foods
have healthy effects in human beings.
Now, on a population level
folks could benefit from just lowering their protein intake.
Period!
"The mean intake of proteins (and thus methionine)
of Western human populations is much higher than needed.
Therefore, decreasing such levels has a great potential
to lower tissue oxidative stress
and to increase healthy life span in humans
while avoiding the possible undesirable effects of caloric restriction."
First thing we can recommend is just decreasing
the intake of protein, that has a large potential
to bring about health benefits,
but then we can lower methionine even further
eating a plant-based diet.
The reason plant-based diets
are so protective is not known.
Yes, vegetables contain thousands of phytochemicals,
but separately investigating their possible protective roles
will be an impossible task.
The idea that the protective effect
is not due to any of the individual plant food components,
but to a synergic “combined effect” is gaining acceptance.
However, based on the relationship
of excess dietary methionine with toxicity
to major vital organs and its likely mechanism of action
through increase in free radical generation,
the possibility exists that the protective effects
of plant-based diets can be due,
at least in part, to their lower methionine content.
This is not a new idea.
It was proposed back in 2009,
but is only now gaining increasing acceptance
in more mainstream scientific circles.
The idea that "The low-methionine content of vegan diets
may make methionine restriction feasible as a life extension strategy."
In our next story, we learn how plant-based diets
may prove to be a useful nutrition strategy
because these diets are naturally lower in methionine.
In designing an antibiotic,
you wouldn't create a drug that destroyed DNA, for example,
because that's something that both humans and bacteria share in common.
It would kill the bacteria, all right,
but it might kill us too.
So, many antibiotics work by attacking the bacterial cell wall,
something bacteria have that we don't.
Antifungals can attack the unique cell walls of fungus.
Pesticides can work by attacking the special exoskeleton of insects.
But fighting cancer is harder,
because cancer cells are our own cells.
So, fighting cancer comes down to trying to find and exploit
differences between cancer cells and normal cells.
Forty years ago, a landmark paper was published
showing for the first time that many human cancers
have what's called absolute methionine dependency,
meaning you can grow normal cells in a petri dish
without given them the amino acid methionine—
normal cells thrive,
but without methionine, cancer cells die.
Normal breast cells, for example,
grow no matter what, with or without,
but here's leukemia cells—
they need that extra added methionine
to grow or they just flat-line.
What does cancer do with the methionine?
Tumors generate gaseous sulphur- containing compounds with it,
that specially trained diagnostic dogs can actually pick up.
There are mole sniffing dogs that can pick out skin cancer.
There are breath-sniffing dogs
that can pick out people with lung cancer.
Pee-sniffing dogs that can diagnose bladder cancer and,
yes - you guessed it.
Fart-sniffing dogs for colorectal cancer.
Doctors can now bring their lab to the lab…
Gives a whole new meaning to the term "pet scan."
Anyway, methionine dependency
is not just present in cancer cell lines in a petri dish,
Fresh tumors taken from patients show that many cancers
appear to have biochemical defects
that makes them methionine dependent,
including some tumors of the colon, breast,
ovary, prostate, and skin.
Chemo companies are fighting to be the first
to come out with a methionine- depleting drug,
but since methionine is sourced mainly from food
a better strategy may be to lower methionine levels
by lowering methionine intake,
eliminating high methionine foods, for cancer growth control.
Here's the thinking: look, smoking cessation,
consumption of diets rich in plants, and other lifestyle measures
can prevent the majority of cancers.
Unfortunately, people don't do them, and as a result,
each year hundreds of thousands of Americans develop metastatic cancer.
Chemotherapy cures only a few types of metastatic cancer.
Unfortunately, the vast majority of common metastatic cancers,
like breast, prostate, colon, and lung are lethal.
We therefore desperately need novel treatment strategies for metastatic cancer,
and dietary methionine restriction may be one such strategy.
So, where is methionine found?
Particularly, chicken and fish,
milk, red meat and eggs have less,
but if you really want to stick with lower methionine foods,
fruits, nuts, veggies, grains, and beans.
In other words, methionine restriction may be achieved
using a predominantly vegan diet.
So, why isn't every oncologist doing this?
"Despite many promising preclinical and clinical studies in recent years,
dietary methionine restriction and other dietary approaches
to cancer treatment have not yet gained widespread clinical application.
Most clinicians and investigators are probably unfamiliar
with nutritional approaches to cancer"... (ah...that's an understatement).
"Many others may consider amino acid restriction as an 'old idea',
since it has been examined for several decades.
However, many good ideas remain latent for decades if not centuries
before they prove valuable in the clinic.
With the proper development, dietary methionine restriction,
either alone or in combination with other treatments,
may prove to have a major impact on patients with cancer.“
We would love it if you could share with us your stories
about reinventing your health
through evidence-based nutrition.
Go to nutritionfacts.org/testimonials.
We may share it on our social media to help inspire others.
To see any graphs, charts, graphics,
images, or studies mentioned here,
please go to the Nutrition Facts Podcast landing page.
There you’ll find all the
detailed information you need –
plus, links to all of the sources we cite to each of these topics.
For a timely text on
the pathogens that cause pandemics,
order the e-book, audiobook, or hard copy
of my last book, “How to Survive a Pandemic”.
For recipes, check out my second-to-last book, my “How Not to Diet Cookbook”. It’s
beautifully designed with more than 100 recipes for delicious and nutritious meals.
And all the proceeds I receive from
the sales of all my books goes to charity.
NutritionFacts.org is a nonprofit, science-based public service,
where you can sign up
for free daily updates
on the latest in nutrition research via bite-sized videos and articles.
Everything on the website is free.
There’s no ads,
no corporate sponsorship.
It’s strictly non-commercial. I’m not selling anything.
I just put it up as a public service,
as a labor of love,
as a tribute to my grandmother,
whose own life was saved with evidence-based nutrition.