0:00

Let's say you're trying to find

0:02

some solid information about a serious

0:04

health problem that concerns you—high blood

0:06

pressure, diabetes. Yet

0:08

everywhere you look, someone's trying

0:11

to sell you something, like

0:13

vitamins, yoga mats, blenders,

0:16

drugs. Well, breathe

0:18

a sigh of relief, because all we

0:20

bring you are the

0:22

facts. Welcome to the Nutrition Facts Podcast.

0:24

I'm your host, Dr. Michael Greger. Did

0:27

you know that there's been a steep rise in

0:29

cases of asthma over the years, and that

0:32

much of that can be attributed to an increase

0:34

in air pollution? Well, it

0:37

turns out that some diets can

0:39

improve our respiratory defense against lung

0:41

disease and infection. Here's

0:43

our first story. Outdoor

0:46

air pollution may be the ninth

0:48

leading cause of death and disability

0:50

in the world, responsible

0:52

for millions of deaths from

0:54

lung cancer, emphysema, heart disease,

0:57

stroke, and respiratory infection. In

0:59

the U.S., living in a polluted city

1:02

was associated with a 16%, 27%, and 28% increase in

1:06

total cardiovascular and lung

1:08

cancer death, compared to

1:10

living in a city with cleaner air. Living

1:13

in a city with polluted air may lead up to a 75% increase

1:17

in the risk of a heart attack. No

1:20

one wants to be living in a traffic jam, but

1:23

is better than dying in a

1:25

traffic jam. In

1:27

addition to causing deaths, air pollution

1:29

is also the cause of a number of

1:32

health problems. It may not only exacerbate asthma,

1:35

but increase the risk of developing asthma

1:37

in the first place. These

1:39

pollutants may trigger liver disease,

1:43

even increase the risk of diabetes.

1:46

Even when atmospheric pollutants are

1:49

within legally established limits, they

1:51

can be harmful to health. So

1:54

what can we do about it? Paper

1:56

after paper describing all the terrible things

1:58

air pollution can do to us, but

2:00

most failed to mention public

2:03

policy. We're making great strides

2:05

in demonstrating the harmful effects, but

2:07

public authorities are not using these

2:10

data to reduce emissions, as

2:12

they might inconvenience the population, and

2:15

therefore might not be politically acceptable.

2:19

To treat the cause, we

2:22

need better vehicle inspections, efficient public

2:24

transport, bus lanes, bicycle lanes, even

2:27

urban tolls to help clean up

2:29

the air. While

2:31

we're waiting for all that, is there

2:33

anything we can do to protect ourselves?

2:36

Well, our body naturally

2:39

has detoxifying enzymes, not

2:41

only in our liver, but lining

2:44

our airways. Studies

2:46

showing that people born with less

2:48

effective detox enzymes have

2:50

an exaggerated allergic response to

2:52

diesel exhaust, suggesting that these

2:54

enzymes actively combat the inflammation

2:56

caused by pollutants in the

2:58

air. A significant part

3:01

of the population has these substandard

3:03

forms of the enzyme, but

3:05

either way, what can we do

3:07

to boost the activity of whichever

3:09

detoxification enzymes we do have? Well,

3:12

if you remember broccoli can dramatically

3:14

boost the activity of the detox

3:16

enzymes in our liver, but

3:18

what about our lungs? Smokers

3:21

fed some smokers a large stock of broccoli

3:24

every day for 10 days to see if

3:26

it would affect the level of inflammation within

3:28

their bodies. Why smokers? Because

3:32

smoking is so inflammatory, you

3:35

can end up with elevated C-reactive

3:37

protein levels for up to 30

3:39

years after quitting, and

3:42

that inflammation can start almost immediately

3:44

after we start smoking, so it's

3:46

critical to never start

3:49

in the first place. But

3:51

if you do, you can cut

3:53

your level of that inflammation biomarker

3:56

CRP nearly in half after just

3:58

10 days eating. a

4:00

lot of broccoli. Appears

4:02

to cut inflammation in non-smokers as

4:04

well, maybe explaining in part

4:07

why eating more than 2 cups of

4:09

broccoli, cabbage, cauliflower, kale, or other cruciferous

4:11

veggies a day is associated with 20%

4:13

reduced risk of dying compared

4:17

to eating a third a cup a day

4:19

or less. So

4:21

what about air pollution? We

4:24

know the cruciferous compound is the

4:26

most potent known inducer of our detox

4:28

enzymes, and so most

4:30

of the research has been its

4:32

ability to fight cancer. They

4:34

tried to see if it could

4:37

combat the pro-inflammatory impact of pollutants

4:39

such as diesel exhaust. They

4:41

took some human lung lining cells in a

4:43

petri dish and drip on

4:45

some broccoli goodness. Yeah,

4:47

but we don't inhale broccoli, we don't snort

4:50

it, we eat it. Can it still get

4:52

into our lungs and help? Yes,

4:55

two days of broccoli sprout consumption, then

4:58

you suck some cells out of their nose, and

5:01

up to 100 times more detox

5:03

enzyme expression compared to eating a

5:05

non-cruciferous vegetable alfalfa sprouts. Now

5:08

all we have to do is squirt some

5:10

diesel exhaust up their nose, which

5:13

is what some UCLA researchers

5:15

did, an amount equal

5:17

to daily rush hour

5:19

exposure on the Los Angeles freeway.

5:22

Within six hours, the number of inflammatory

5:24

cells in their nose shot up and

5:27

continued to rise. But

5:30

in the group that had been getting

5:32

a broccoli sprout extract, the inflammation went

5:34

down and stayed down. Since

5:39

the dose in these studies is equivalent to the

5:41

consumption of one or two cups of broccoli, their

5:44

study demonstrates the potential

5:46

preventative and therapeutic potential

5:48

of broccoli. But

5:50

if broccoli is so powerful at suppressing

5:52

this inflammatory immune response, might

5:55

it interfere with normal immune function?

5:58

After all, the battle with viruses like influenza

6:00

can happen in the nose. Let's

6:03

drip some flu viruses into the nostrils

6:05

of broccoli sprout eaters

6:08

and find out. And

6:10

what you get is the best

6:12

of both worlds, less inflammation,

6:15

yet an improved immune response.

6:18

After eating a package of broccoli sprouts every

6:20

day, our body is able

6:22

to keep the virus in check, potentially

6:25

offering a safe, low-cost strategy

6:28

for reducing influenza risk

6:30

among high-risk populations. So

6:33

better immune function, yet less

6:36

inflammation, potentially reducing the

6:38

impact of pollution on allergic

6:40

disease and asthma, at least

6:42

for an enthusiastic broccoli consumer.

6:45

But what about cancer? Detoxifying

6:48

air pollutants throughout the rest of our

6:50

body? We didn't know, until now.

6:55

Off to China, where they have

6:57

some of the worst air pollution in the

6:59

world, and by day one, those getting the

7:01

broccoli sprouts were able to get rid of

7:03

60% more benzene from

7:05

their bodies— a rapid,

7:08

highly durable elevation in

7:10

the detoxification of a

7:12

known human carcinogen. Now

7:15

this was using broccoli sprouts, which are

7:17

highly concentrated, equivalent to about 5 cups

7:19

of broccoli a day. So

7:21

we don't know how well more modest

7:23

doses would work, but if

7:25

they do, eating broccoli could

7:28

provide a frugal means to attenuate the

7:30

long-term health risks of air

7:32

pollution. Finally

7:35

today, if the nitrites in foods

7:37

like ham and bacon cause lung

7:39

damage, what about

7:41

processed meat with quote-unquote no nitrites

7:43

added? Recently, the

7:46

World Health Organization classified processed

7:48

meat, also known as cured

7:50

meat—bacon, ham, hot dogs, lunch

7:53

meat, sausage— as definitively

7:55

cancer-causing in humans.

7:59

As if— If that's not enough, high-process

8:01

meat consumption has also been associated

8:04

with increased risk of dying prematurely

8:06

from all causes put together as

8:09

a risk factor for several

8:11

major chronic diseases, such as

8:13

type 2 diabetes, coronary heart

8:15

disease, and stroke. What

8:18

about lung issues like asthma?

8:21

Nitrites are added to processed meats

8:23

as preservatives to preserve their pink,

8:26

so they don't turn gray, keeping

8:28

them less rancid tasting, and to

8:30

present the growth of diseases like

8:33

botulism. But put that

8:35

same sodium nitrite in a drinking

8:37

water of lab animals, and they

8:40

develop emphysema. They nearly all developed

8:42

emphysema. But that's all

8:45

the scientific knowledge we had

8:47

until this study, which found that frequent

8:50

cured meat consumption is associated

8:52

with increased risk for developing

8:54

diseases like emphysema in people

8:56

too. Chronic obstructive

8:58

pulmonary disease, eating it

9:00

like every other day, appeared

9:03

to triple the odds of severe

9:05

COPD. Most of it

9:07

was just a snapshot-in-time study, so we

9:09

don't know which came first, the Sausage

9:11

or the COPD for that. We need

9:14

prospective studies to follow people over time,

9:16

and the big twin Harvard studies in

9:18

both women and men,

9:21

both found that the risk

9:23

of newly diagnosed COPD increased with

9:25

a greater consumption of cured

9:27

meats. Currently, we

9:29

now have studies involving hundreds of thousands

9:32

of people showing that higher intakes of

9:34

processed meat were associated with a 40%

9:37

increased risk of COPD. It

9:40

comes down to like an 8%

9:42

higher risk of COPD for each hot

9:44

dog you eat all week, or

9:47

each weekly breakfast-length

9:49

sausage. What's going

9:52

on? Yes, there are

9:54

advanced glycation end products, so-called glycotoxins

9:56

that may be pro-inflammatory.

10:00

saturated fat that can also trigger

10:02

inflammation in the airways. The

10:05

high salt content can present

10:07

a potential risk for lung

10:09

inflammation, where the increase in

10:12

systemic inflammation in general. But

10:15

the reason that tension is focused on the

10:17

nitrites is because nitrites may actually be one

10:19

of the mechanisms by which tobacco

10:21

smoke causes diseases like

10:24

emphysema. Yes, cured meats are

10:26

the principal source of dietary

10:28

nitrites, and nitrites are also

10:30

byproducts of tobacco smoke. One

10:32

of the main constituents besides

10:34

the carbon monoxide and nicotine

10:36

are nitrogen oxides that are

10:38

converted in the lung to

10:40

nitrites. The way

10:42

nitrites appear to cause lung

10:44

damage is by affecting connective

10:46

tissue proteins like collagen and

10:48

elastin. That's what helps keep

10:50

the air spaces in your lungs open. But

10:54

nitrite can modify these proteins

10:56

in a way that mimic

10:58

age-related damage including the

11:00

fragmentation of elastin. With

11:03

that much lung injury, it's logical

11:06

to assume processed meat consumption could

11:08

also exacerbate the disease

11:10

of those who already have it.

11:13

And indeed, cured meat

11:15

consumption increases risk of COPD

11:17

patients ending up back in

11:20

the hospital. About twice the risk

11:22

for those eating more than average, and

11:24

appears the more you eat, the

11:27

worse it is. Regarding

11:30

lung health, processed meat intake has been

11:32

associated with a likely increased risk of

11:34

lung cancer, decline in

11:36

lung function, and chronic obstructive

11:39

pulmonary diseases. But

11:41

what about asthma? High

11:43

processed meat consumption has been associated

11:45

with higher asthma symptoms as well.

11:47

We knew about the higher maternal

11:49

intake of meat before pregnancy, potentially

11:51

increasing the risk of wheezing in

11:53

her children later on, based

11:56

on a study of more than

11:58

a thousand mother child parents. and

12:01

we're not talking about aspirating meat

12:03

into your lungs and being

12:05

misdiagnosed with asthma. Those

12:07

who eat the most cured meats were 76% more likely to

12:11

experience worsening asthma than those who

12:13

ate the least. Since

12:16

obesity is a likely risk factor

12:18

for asthma, though maybe the influence

12:20

of the meat is just indirect

12:22

by contributing to weight gain, that

12:25

might be a small part of it, but

12:27

the main effect appears to be direct,

12:30

suggesting a deleterious role of cured

12:32

meat independent of weight. Put

12:35

all those studies together and process meat

12:37

into it. It appears to be an important

12:39

target for the prevention of adult asthma

12:41

in the first place. Even

12:44

if you don't have any long issues,

12:47

processed meat consumption was negatively associated with

12:49

measures of normal lung function, while

12:52

fruit and vegetable consumption and

12:54

dietary total antioxidant capacity was

12:56

associated with better lung function.

12:59

But wait, you say, I just eat

13:02

all natural, uncured hot dogs

13:05

with no nitrates or nitrites

13:07

added in all caps.

13:10

But if you magnifying glass the

13:12

small print, it says, except those

13:14

naturally occurring in cultured celery juice.

13:17

See, to avoid saying they

13:20

added nitrites, what they

13:22

do is add something that has lots

13:24

of nitrates like celery and a bacteria

13:26

that converts the nitrates to nitrites. So

13:28

they are adding nitrites.

13:31

They're just straight up duping

13:33

consumers. We didn't

13:35

add any nitrites, except

13:37

of course for all the nitrites

13:39

we added. We care

13:42

about your health, so no nitrites

13:44

added. And who wants pepperoni with

13:46

nitrites? So we just added

13:49

lots of nitrites. We

13:51

would never add any

13:54

nitrites. Just let

13:56

the pinky picture distract you from the fact that we

13:59

just lied. Head to your face,

14:02

Cormel was my

14:04

favorite, except for those naturally occurring

14:06

in seasoning. Pretty slick. Europe

14:10

doesn't allow this kind of consumer

14:12

fraud, demanding manufacturers explicitly label it

14:14

as containing nitrites. I mean, you

14:17

can't even call it natural. When

14:20

Consumer Reports put it to the

14:22

test, they found the nitrite levels

14:24

in all the products was essentially

14:26

the same. So no nitrites doesn't

14:29

mean no nitrites. Consumer

14:32

Reports and the Center for Science and the

14:34

Public Interest have petitioned to stop

14:37

this misleading practice. Nitrites

14:40

are nitrites. Their chemical composition is absolutely

14:43

the same, and so are the health

14:45

of some of them. We

14:47

will love it. If you could share

14:50

with us your stories about reinvents your

14:52

health through evidence-based nutrition, go to nutritionfacts.org/testimonials.

14:54

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on social media to help inspire others.

15:00

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15:02

charts, graphics, images, or studies mentioned here,

15:04

go to the Nutrition Facts Podcast landing

15:06

page. There you'll find all the detailed

15:08

information you need, plus links

15:10

to all the sources we cite for each

15:13

of these topics. My

15:15

last two books for our How to Survive

15:17

a Pandemic and my How Not to Diet

15:19

textbook get ready this year for

15:21

the launch of How Not to Age, and of

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course all the proceeds for the sales of all

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my grandmother, whose own life was saved

15:55

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