Flashback Friday: Best Food to Counter the Effects of Air Pollution

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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% 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% 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% 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. But, here, for the first time, 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 this is how many detox enzymes are produced. Drip on some broccoli goodness, and you can get this many. 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. Eat alfalfa sprouts, and you can get this kind of viral spike in your nose. But, 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.

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Image credit: pixakame via pixabay. Image has been modified.

Video credit: Tyler McReynolds, Teetotalin LLC.