Did you know that there has been a steep rise in cases of asthma over the years and that much of that can be attributed to an increase in air pollution? Well, it turns out that some diets can improve our respiratory defense against lung disease and infection. Here’s our first story.
Outdoor air pollution may be the ninth leading cause of death and disability in the world, responsible for millions of deaths from lung cancer, emphysema, heart disease, stroke, and respiratory infection. In the U.S., living in a polluted city was associated with a 16, 27, and 28 percent increase in total, cardiovascular, and lung cancer death, compared to living in a city with cleaner air. Living in a city with polluted air may lead [to] up to a 75 percent increase in the risk of a heart attack. No one wants to be living in a traffic jam, but it’s better than dying in a traffic jam.
“In addition to causing deaths, air pollution is also the cause of a number of…health problems.” It may not only exacerbate asthma, but increase the risk of developing asthma in the first place. These pollutants may trigger liver disease, even increase the “risk of diabetes.” “[E]ven when atmospheric pollutants are within legally established limits, they can be harmful to health.” So, what can we do about it?
Paper after paper describing all the terrible things air pollution can do to us, but most failed to mention public policy. We’re making “great strides in demonstrating the harmful effects, [but] public authorities are not using these data to” reduce emissions, as they might inconvenience the population, “and, therefore, might not be politically acceptable.”
To treat the cause, we need better “vehicle inspections, efficient public transport,…bus lanes, bicycle lane[s], [even] urban tolls”—to help clean up the air. While we’re waiting for all that, is there anything we can do to protect ourselves?
Well, our body naturally has detoxifying enzymes, not only in our liver, but lining our airways. Studies showing that people born with less effective detox enzymes have an exaggerated allergic response to diesel exhaust, suggesting that these enzymes actively combat the inflammation caused by pollutants in the air. A significant part of the population has these substandard forms of the enzyme, but either way, what can we do to boost the activity of whichever detoxification enzymes we do have?
Well, if you remember, broccoli can dramatically boost the activity of the detox enzymes in our liver. But, what about our lungs? Researchers fed some smokers a large stalk of broccoli every day for ten days to see if it would affect the level of inflammation within their bodies. Why smokers? Because smoking is so inflammatory that you can end up with elevated C-reactive protein levels for “up to 30 years…after quitting,” and that inflammation can start almost immediately after we start smoking. So, it’s critical to never start in the first place.
But, if you do, you can cut your level of that inflammation biomarker CRP nearly in half, after just ten days eating a lot of broccoli. Appears to cut inflammation in nonsmokers as well—maybe explaining, in part, why eating more than two cups of broccoli, cabbage, cauliflower, kale, or other cruciferous veggies a day is associated with 20 percent reduced risk of dying, compared to eating a third [of] a cup a day, or less.
So, what about air pollution? We know the cruciferous compound is “the most potent known inducer” of our detox enzymes; and so, most of the research has been on its ability to fight cancer. They tried to see if it could combat “the proinflammatory impact of…pollutants such as diesel exhaust.” They took some human lung lining cells in a petri dish and drip on some broccoli goodness. Yeah, but we don’t inhale broccoli; we don’t snort it; we eat it. Can it still get into our lungs and help? Yes, two days of broccoli sprout consumption, then you suck some cells out of their nose, and up to 100 times more detox enzyme expression, compared to eating a non-cruciferous vegetable (alfalfa sprouts). Now, all we have to do is squirt some diesel exhaust up their nose, which is what some UCLA researchers did—an amount equal to daily rush-hour exposure on the Los Angeles freeway. Within six hours, the number of inflammatory cells in their nose shot up and continued to rise. But in the group that had been getting a “broccoli sprout extract,” the inflammation went down, and stayed down.
Since the dose in these studies is equivalent to the consumption of one or two cups of broccoli, their “study demonstrates the potential preventive and therapeutic potential of broccoli.”
But, if broccoli is so powerful at suppressing this inflammatory immune response, might it interfere with normal immune function? After all, the battle with viruses, like influenza, can happen in the nose. Let’s drip some flu viruses into the nostrils of broccoli sprout eaters, and find out. And, what you get is the best of both worlds—less inflammation, yet an improved immune response. After eating a package of broccoli sprouts every day, our body is able to keep the virus in check, potentially offering “a safe, low-cost strategy for reducing influenza risk” among high risk populations. So, better immune function, yet less inflammation, potentially “reducing the impact of…pollution on allergic disease and asthma”—at least for “an enthusiastic broccoli consumer.”
But, what about cancer, detoxifying air pollutants throughout the rest of our body? We didn’t know, until now. Off to China, where they have some of the worst air pollution in the world. And, by day one, those getting the broccoli sprouts were able to get rid of 60% more benzene from their bodies, a “rapid…highly durable elevation [in] the detoxification of…a known human carcinogen.” Now, this was using broccoli sprouts, which are highly concentrated—equivalent to about five cups of broccoli a day. So, we don’t know how well more modest doses would work. But, if they do, eating broccoli could provide “a frugal means to attenuate [the] long-term health risks” of air pollution.
Finally, today, if the nitrites in foods like ham and bacon cause lung damage, what about processed meat with “no nitrites added”?
Recently, the World Health Organization classified processed meat, also known as cured meat—bacon, ham, hot dogs, lunch meat, and sausage—as definitively cancer-causing in humans. As if that’s not enough, high processed meat consumption has also been associated with increased risk of dying prematurely from all causes put together and is a risk factor for several major chronic diseases, such as type 2 diabetes, coronary heart disease, and stroke. But what about lung issues like asthma?
Nitrites are added to processed meats as preservatives to preserve their pink (so they don’t turn gray), keeping them less rancid-tasting, and to prevent the growth of diseases like botulism. But put that same sodium nitrite in the drinking water of lab animals, and they develop emphysema. They nearly all developed emphysema. But that’s all the scientific knowledge we had until this study, which found that frequent cured meat consumption is associated with increased risk for developing diseases like emphysema in people, too––a form of chronic obstructive pulmonary disease (COPD). Eating it like every other day appeared to triple the odds of severe COPD. But it was just a snapshot-in-time study; so, we don’t know which came first––the sausage or the COPD. For that, we need prospective studies that follow people over time, and the big twin Harvard studies in both women and men both found that the risk of newly-diagnosed COPD increased with a greater consumption of cured meats.
Currently, we now have studies involving hundreds of thousands of people, showing that higher intakes of processed meat were associated with a 40 percent increased risk of COPD. It comes out to like an 8 percent higher risk of COPD for each hot dog you eat a week or each weekly breakfast link sausage. What is going on?
Yes, there are advanced glycation end-products, so-called glycotoxins, that may be proinflammatory. There’s the saturated fat that can also trigger inﬂammation in the airways. The high salt content can present a potential risk for lung inflammation, or the increase in systemic inflammation in general. But the reason attention has focused on the nitrites is because nitrites may actually be one of the mechanisms by which tobacco smoke causes diseases like emphysema. Yes, cured meats are the principal source of dietary nitrites, but nitrites are also byproducts of tobacco smoke. One of the main constituents, besides the carbon monoxide and nicotine, are nitrogen oxides that are converted in the lung to nitrites.
The way nitrites appear to cause lung damage is by affecting connective tissue proteins like collagen and elastin. That’s what helps keep the airspaces in your lungs open, but nitrite can modify these proteins in a way that mimics age-related damage, including the fragmentation of elastin.
With that much lung injury, it’s logical to assume processed meat consumption could also exacerbate the disease of those who already have it. And indeed, cured meat consumption increases risk of COPD patients ending up back in the hospital, about twice the risk for those eating more than average, and it appears the more you eat, the worse it is.
Regarding lung health, processed meat intake has been associated with a likely increased risk of lung cancer, a decline in lung function, and chronic obstructive pulmonary diseases. But, what about asthma? High processed meat consumption has been associated with higher asthma symptoms as well.
We knew about higher maternal intake of meat before pregnancy, potentially increasing the risk of wheezing in her children later on (based on a study of more than a thousand mother-child pairs). And we’re not talking about aspirating meat into your lungs and being misdiagnosed with asthma. Those who ate the most cured meats were 76 percent more likely to experience worsening asthma than those who ate the least. Since obesity is a likely risk factor for asthma, though, maybe the influence of the meat is just indirect, by contributing to weight gain? That might be a small part of it, but the main effect appears to be direct, suggesting a deleterious role of cured meat independent of weight. Put all the studies together, and processed meat intake appears to be an important target for the prevention of adult asthma in the first place.
Even if you don’t have any lung issues, processed meat consumption was negatively associated with measures of normal lung function, while fruit and vegetable consumption and dietary total antioxidant capacity was associated with better lung function.
But wait, you say. I just eat all-natural, uncured hot dogs, with NO NITRATES OR NITRITES ADDED, in all caps. But if you magnifying glass the small print, it says “except those naturally occurring in…cultured celery juice.” See, to avoid saying they added nitrites, what they do is add something that has a lot of nitrates, like celery, and bacteria that convert the nitrates to nitrites. So, they are adding nitrites. They’re just straight-up duping consumers. We didn’t add any nitrites except, of course…for all the nitrites we added. We care about your health; so, no nitrites added. Who wants pepperoni with nitrites? So, we just added lots of nitrites. We would never add any nitrites. Now, just let the piggy picture distract you from the fact that we just lied to your face. Hormel was my favorite. “Except for those naturally occurring in seasoning”—pretty slick.
Europe doesn’t allow this kind of consumer fraud, demanding manufacturers explicitly label it as containing nitrites. You can’t even call it natural.
When Consumer Reports put it to the test, they found the nitrite levels in all the products were essentially the same; so “no nitrites” doesn’t mean no nitrites. Consumer Reports and the Center for Science in the Public Interest have petitioned to stop this misleading practice. Nitrites are nitrites. “Their chemical composition is absolutely the same, and so are the health eﬀects.”