 Let's say you're trying to find some solid information about a serious health problem that concerns you, high blood pressure, diabetes. Yet everywhere you look, someone's trying to sell you something like vitamins, yoga mats, blenders, drugs. Well, breathe a sigh of relief, because all we bring you are the facts. Welcome to the Nutrition Facts Podcast. I'm your host, Dr. Michael Greger. Did you know that there's 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 US, living in a polluted city was associated with a 16, 27, and 28% 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 up to a 75% increase in the risk of a heart attack. No one wants to be living in a traffic jam, but is 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. Even 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 fail 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 lanes, 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 stock of broccoli every day for 10 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 10 days eating a lot of broccoli. Appears to cut inflammation in non-smokers 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% 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 its ability to fight cancer. They tried to see if it could combat the pro-inflammatory impact of pollutants such as diesel exhaust. They took some human lung lining cells in a petri dish and dripped 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 preventative 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 5 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 quote-unquote no nitrites added? Recently, the World Health Organization classified processed meat, also known as cured meat, in bacon, ham, hot dogs, lunch meat, 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. What about lung issues like asthma? Nitrites are added to processed meat, as preservatives to preserve their pink, so they don't turn gray, keeping them less rancid tasting, and to present the growth of diseases like botulism. But put that same sodium nitrite in a 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 to chronic obstructive pulmonary disease. 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 to 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 the 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% increased risk of COPD. It comes out to like an 8% higher risk of COPD for each hot dog you eat all week, or each weekly breakfast-linked sausage. What's going on? Yes, there are advanced glycation end products, so called glycotoxins that may be pro-inflammatory. 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 is focused on the nitrites is because the 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 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 air spaces in your lungs open. But nitrite can modify these proteins in a way that mimic 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 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-process meat consumption has been associated with higher asthma symptoms as well. We knew about the higher maternal intake of meat before pregnancy, potentially increasing the risk of wheezing in our children later on, based on a study of more than 1,000 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% 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 those 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 long 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 magnify and 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 lots of nitrates, like celery, and a bacteria that converts the nitrates to nitrites. So they ARE adding nitrites. They're just straight-up dooping 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. And who wants pepperoni with nitrites? So we just added lots of nitrites. We would never add any nitrites. Just let the pinky picture distract you from the fact that we just lied to your face. Cormel 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. I mean, you can't even call it natural. When Consumer Reports put it to the test, they found the nitrite levels in all the products was 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. We would love it if you could share with us your stories about reinventing your health through evidence-based nutrition. Go to NutritionFacts.org slash Testimonials, which may be able to share it on social media to help inspire others. If you'd like to see any graphs, charts, graphics, images or studies mentioned here, go to the Nutrition Facts Podcast landing base. There you'll find all the detailed information you need, plus links to all the sources we cite for each of these topics. My last two books were How to Survive a Pandemic and My How Not to Diet Cookbook. Get ready this year for the launch of How Not to Age, and of course all the proceeds for the sales of all my books goes directly to charity. NutritionFacts.org is a non-profit science-based public service where you can sign up for free daily updates on the latest in nutrition research with bite-sized videos and articles uploaded nearly every day. Everything on the website is free. There are no ads, no corporate sponsorships, no kickbacks. It's strictly non-commercial, 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.