Changes in your diet not only affect you physically,
physiologically inside,
but also mentally, how well you think,
psychologically, how well you feel.
But you’ll never know just how good you can feel
until you put it to the test and try eating healthy.
Welcome to the NutritionFacts Podcast.
I’m your host, Dr. Michael Greger.
Today we feature a wide variety of research
and we start with a study that reveals an effective way
to help people reduce their meat consumption.
According to a survey of more than 30,000 U.S. residents,
a third of American adults self-identify as meat reducers,
meaning one in three of us is trying to cut down on our meat consumption.
Why?
For those earning less than $40,000 a year, the #1 reason is cost;
for those earning more than $40K, the #1 reason is health.
And indeed, if we were to define a healthy diet,
compared to how we're eating now,
we should be eating more plant-based foods,
including fresh fruits and vegetables, whole grains, legumes --
meaning beans, split peas, chickpeas, and lentils -- seeds and nuts,
and at the same time lower in animal foods,
particularly fatty and processed meats.
In an editorial entitled
"Plant-Based Diets for Personal, Population, and Planetary Health,"
co-authored by the chair of nutrition at Harvard,
healthy plant-based diets are not only more sustainable,
but have also been associated with lower risk of chronic diseases
such as obesity, type 2 diabetes, cardiovascular disease,
and some cancers.
What do we mean by plant-based?
Basically, any diet that reduces the amount of animal products
and increases the amount of plants --
again, vegetables, fruits, whole grains, legumes, nuts, and seeds.
Transitioning global diets towards healthy plant-based dietary patterns
would require large-scale public health efforts
but could be instrumental in ensuring future human and planetary health.
Indeed, the IPCC, the Intergovernmental Panel on Climate Change,
describes plant-based diets as a major opportunity for mitigating
and adapting to climate change
and includes a policy recommendation to reduce meat consumption.
Okay, but how do you do it?
In a systematic review of experimental studies on strategies
to reduce meat consumption,
one of the most effective experiments came out of the Midwest.
Sadly, research shows that the provision of information on its own
can be of limited utility in facilitating behavioral change.
However, default interventions have been successfully employed
in a variety of prosocial contexts, making the right option or
the healthiest option, the easiest option --
the default option.
Take for example, organ donation.
Every year, thousands of people in the United States
have died waiting for a suitable donor organ.
But wait -- 85% of Americans approve of organ donation,
yet less than half have made a decision about donating, and
fewer still have granted permission by signing a donor card.
If you look at Europe, there's nearly a ten-fold difference
in the organ donor rates across different countries.
In some countries, consent is only about 10%,
while in others it's up to like 99.9%.
What's the difference between the two colors?
Gold is opt-in; blue is opt-out.
In opt-out countries, the default is that people are organ donors
unless they actively register not to be.
In the opt-in countries like the United States,
the default is nobody is an organ donor
without explicitly registering to be one.
So there's all sorts of calls for campaigns to change public attitudes
about organ donation, but remember 85% are already on board.
If we want to change behavior and not just attitudes,
changing the default condition may be more effective.
So does it work for diet?
In the DEFAULT treatment, participants received at their table
a menu listing only five meat-free options.
But they were informed -- verbally and in writing on the menu --
that they could also consult a second menu that was posted on the wall
about a dozen feet away, which had your standard array
of popular nonvegetarian dining hall dishes.
And in the control condition both lists of options
were mixed together on the same menu they were handed.
And when you do that, only a minority of people
choose the meat-free options, between 5 and 40%,
depending on if you describe the meat-free options
in an appealing way, like pasta with Provencal vegetables,
or in unappealing terms like vegan calzone.
Okay, but what about the default condition,
where the menu in front of them is all meat-free.
They can still get up and order all the meat they want,
but the alternate menu is a few steps away.
You're not taking away any people's options,
but just by making it the default,
meat-free choices shot up like to 75 and 90%.
Even an unappealingly described meat-free option totally won out.
And even just adding more veg options, from a quarter of the options
to half the options, may increase the sales
of the veg options between about 40 to 80%.
In our next story,
I share a touching story of the power of plant-based eating
for chronic kidney failure.
Is it possible to ameliorate chronic kidney disease
using a whole food, plant-based diet?
In my last video on kidney disease,
I talked about how randomizing people to cut just around
10 grams of protein from their daily diet could cut their risk
of dialysis and death by a whopping 77%.
That was cutting protein across the board.
But while animal-based protein ingestion —
meat, dairy, and egg white protein ingestion —
promotes an acidic environment in the kidneys, inflammation, and
stresses the kidneys to what's called hyperfiltration mode,
plant-based protein can be alkaline-producing and
anti-inflammatory and contain kidney-protective properties.
So, what if you have kidney patients eat a plant-dominant low-protein diet,
abbreviated adorably as PLADO, I guess for plant-dominant.
If you fashion up a plant-based diet index score where you get points
for healthy plant foods
and get points deducted for eating animal foods,
those with serious kidney disease with higher scores were found
to have lower systemic inflammation.
But does that actually translate into living a longer life?
Apparently so.
Even a 10% increase in the proportion of plant-based protein
was associated with a significant reduction in all-cause mortality.
Even just eating more servings of fruits and vegetables, like two a day
compared to two a week, is linked to living longer.
Without fully functioning kidneys,
there are concerns about phosphorus and potassium overload,
though, on a plant-based diet.
But the phosphorus in plant-based foods is not as much of a problem
as the phosphorus additives in processed and animal foods.
And the risk of potassium overload from plant-based diets appears
overstated and not supported by the evidence.
But you don't know about ameliorating chronic kidney disease
using a whole food, plant-based diet until you put it to the test.
Here's a case report of a 69-year-old man with type 2 diabetes,
high blood pressure, and stage 3 chronic kidney disease,
resulting in elevated phosphorus and potassium in the blood,
Interested in changing his diet to improve his medical condition.
That's my kind of patient!
He was on 12 different medications, eating a diet that may actually be
slightly better than the average American:
some whole grains and beans,
but then his doctor advised to try eating whole food, plant-based.
So, oatmeal with fruit and flax, beans and greens,
whole wheat spaghetti and veggies, fruit as snacks.
Counselled to eat as much as he wanted from whole healthy foods;
no carb counting, no calorie counting, no portion size restriction —
improving the quality of food rather than restricting the quantity of food.
He adopted the whole food, plant-based diet, packed with carbs,
yet rapidly reduced his insulin requirements by more than 50%,
and subsequently saw improvements in weight,
blood pressure, and cholesterol.
Because eating healthy can have such a rapid effect
on improving your body's insulin sensitivity,
immediate adjustments in insulin dosing were made.
Within four days, his insulin dose was able to be reduced
from roughly 210 units of insulin a day down to 70 units daily,
and an oral blood-sugar lowering medication had to be stopped
due to rapidly improving blood sugar.
He also was able to stop his carvedilol, the hydrochlorothiazide,
amlodipine, sitagliptin within the first two months
due to improving blood pressure and blood sugars.
His insulin dose was steadily titrated downward.
His pravastatin dose was cut in half, and he lost about 50 pounds.
Okay, so what happened to his stage 3 kidney failure?
He was no longer in stage 3 kidney failure!
Doctors watching this will understand what all these numbers mean.
Here's a graph of his GFR, which is a measure of kidney function,
declining for years before shooting up after he started eating healthy.
He experienced an increase in estimated GFR of 73%,
suggesting that the improvement in estimated kidney function
was greater than what would be expected from weight loss alone.
For example, lose about 60 pounds from bariatric surgery,
and you only get about a 12 to 15% boost.
Bottom line: for individuals with chronic kidney disease,
especially those with obesity, hypertension, or diabetes,
a strict, all-you-care-to-eat whole food, plant-based diet
may confer significant benefit.
I mean, apart from the kidney-specific outcomes,
overall mortality is significantly lower among kidney patients
who eat more plants.
And that's critical because most kidney patients don't even make it
to dialysis because they die first,
most often from cardiovascular disease.
Let's hear from the patient.
"At the outset, it seemed like this was going to be a difficult
and restrictive way to eat,
but I began feeling different almost immediately
and we had to decrease my insulin after ONE day.
It seemed like almost overnight I had more energy than I'd had in years.
Weight I'd been trying to lose for a decade began dropping off.
As the weight came off, I felt lighter, and more able to move my body again.
This lifestyle change has been the greatest gift I've ever received.
I am off most of my medications, I've lost over 70 pounds,
and I've regained control over my health.
I feel empowered by this lifestyle change,
and I finally feel like I'm in charge of my health,
not just an unlucky victim shuffling from one specialist to the next.
My only regret was that I didn't know about this sooner."
Finally today,
we look at how stress and menstrual cycles
can affect the smell of our breath.
According to the American Dental Association,
about 50% of American adults suffer from oral malodor,
with prevalence rates around the world ranging from 2% to nearly 80%.
On average, it seems to be about one in three of us on the planet Earth
have bad breath.
What effect might stress have on the smell of our breath?
Stressed students were found to have significantly higher levels
of the "rotten egg" gas, hydrogen sulfide,
which is one of the main volatile sulfur compounds related to bad breath,
originating from the degradation of the sulfur-containing amino acid cysteine,
found concentrated in animal proteins like meat and dairy.
Were they eating different diets or just too busy to brush?
The simplest explanation is just the dry mouth you get
when you're super-stressed, part of our fight or flight response.
It's the same reason we get morning breath,
because we have decreased saliva production when we sleep
that would otherwise self-clean the mouth,
keeping it from becoming like a stagnant pond.
Though maybe stress hormones are having an effect as well.
We suspect sex hormones may play a role, since though men and women
have the same before-and-after rise in bad breath compounds
after a stressful situation,
women seem to start out with higher baseline levels.
Gender appears to play an important role.
Women have significantly worse morning breath, for example,
and bad breath is affected by the menstrual cycle.
In fact, that's listed as one of the causes: so-called menstrual breath.
As you can see, there are higher levels of bad breath compounds
in the mouths of women in the premenstrual and menstrual phases
compared not just to men,
but the follicular phase of their own cycle,
meaning like the first half before ovulation.
Hmm, so maybe bad breath is a hormonal thing more than just a dry mouth thing.
But salivary flow is also lower in menstrual and premenstrual phases.
Check it out: significantly less salivary flow
during menstrual flow and right before.
So, is this all just about having a drier mouth during stress
and certain times of the month?
How could you tease out the effects?
Well, what about studying stressful periods.
PMS, premenstrual syndrome,
is a stressful state characterized by irritability, tension, mood swings.
Is the menstrual dry mouth and bad breath just due to period stress?
Apparently so.
If you split women up into those who experience PMS and
those who don't, it's only those with PMS who suffer the rise
in bad breath compounds as their period arrives.
But the salivary flow was not statistically different.
So the results suggest that a stressful situation can be
a predisposing factor for bad breath that may have nothing to do
with dry mouth or salivary flow.
So what's going on?
It's the effects of the stress hormones themselves
on the production of bad breath compounds.
They dripped some stress hormones on bad breath bacteria---
hormones like adrenaline and cortisol---
and they started churning out more hydrogen sulfide.
What can we do about it
if we can't treat the cause and reduce the stress?
I have videos on dietary changes that can help
as well as tongue cleaning methods.
And I have videos in the works on the effects of gum chewing
and the best mouthwash to use
that doesn't kill the good bacteria in your mouth.
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 NutritionFacts Podcast landing page.
There you’ll find all the detailed information you need –
plus, links to all of the sources we cite for each of these topics.
My last two books are “How to Survive a Pandemic”
and the “How Not to Diet Cookbook”.
Get ready this year for the launch of How Not to Age.
And, of course, all the proceeds I receive from the sales
of all my books goes directly to charity.
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