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Combating Air Pollution Effects with Food

There is a food that offers the best of both worlds—significantly improving our ability to detox carcinogens like diesel fumes and decreasing inflammation in our airways—all while improving our respiratory defenses against infections.

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 United States, living in a polluted city was associated with 16, 27, and 28 percent increases in total, cardiovascular, and lung cancer deaths, compared to living in a city with cleaner air. As well, living in a city with polluted air may lead to up to a 75 percent increase in the risk of a heart attack. “Additionally, the possibility of dying in a traffic jam is two and a half times greater in a polluted city.” No one wants to be living in a traffic jam, but it’s better than dying in one.

In addition to causing deaths, air pollution is also the cause of a number of health problems. It may not only exacerbate asthma but also increase the risk of developing asthma in the first place. These pollutants may trigger liver disease and even increase the risk of diabetes. Indeed, “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 have described all the terrible things air pollution can do to us, but “most…failed to mention public policy. Therefore, while science is making great strides in demonstrating the harmful effects of atmospheric pollution on human health, public authorities are not using these data” to reduce emissions, as such measures might inconvenience the population “and, therefore, might not be politically acceptable.” We need better vehicle inspections, efficient public transport, bus lanes, bicycle lanes, and even urban tolls to help clean up the air, but, while we’re waiting for all of that, is there anything we can do to protect ourselves?

As I discuss in my video Best Food to Counter the Effects of Air Pollution, our body naturally has detoxifying enzymes, not only in our liver, but also lining our airways. Studies show 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?

One of my previous videos Prolonged Liver Function Enhancement from Broccoli investigated how 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? Smoking is so inflammatory that you can have elevated C-reactive protein (CRP) levels for up to 30 years after quitting, and that inflammation can start almost immediately after you start smoking, so it’s critical to never start in the first place. If you do, though, you can cut your level of that inflammation biomarker CRP nearly in half after just ten days eating a lot of broccoli. Broccoli appears to cut inflammation in nonsmokers as well, which may explain in part why eating more than two cups of broccoli, cabbage, cauliflower, kale, or other cruciferous veggies a day is associated with a 20 percent reduced risk of dying, compared to eating a third of a cup a day or less, as you can see at 3:41 in my video.

What about air pollution? We know that the cruciferous compound “is the most potent known inducer” of our detox enzymes, so most of the research has been on its ability to fight cancer. But, for the first time, researchers tried to see if it could combat the pro-inflammatory impact of pollutants, such as diesel exhaust. They put some human lung lining cells in a petri dish, and, as you can see at 4:11 in my video, the number of detox enzymes produced after dripping on some broccoli goodness skyrocketed. Yes, but we don’t inhale broccoli or snort it. We eat it. Can it still get into our lungs and help? Yes. After two days of broccoli sprout consumption, researchers took some cells out of the subjects’ noses and found up to 100 times more detox enzyme expression compared to eating a non-cruciferous vegetable, alfalfa sprouts. If only we could squirt some diesel exhaust up people’s noses. That’s just what some UCLA researchers did, at an amount equal to daily rush hour exposure on a Los Angeles freeway. Within six hours, the number of inflammatory cells in their nose shot up and continued to rise. But, in the group who had been getting a broccoli sprout extract, the inflammation went down and stayed down, as you can see at 4:58 in my video

Since the dose in those studies is equivalent to the consumption of one or two cups of broccoli, their study “demonstrates the potential preventive and therapeutic potential of broccoli or broccoli sprouts,” 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. So what happens when some flu viruses are dripped into the nostrils of broccoli-sprout eaters compared with people consuming non-cruciferous alfalfa sprouts? After eating broccoli sprouts, we get the best of both worlds—less inflammation and an improved immune response. As you can see at 5:55 in my video, after eating alfalfa sprouts, there is a viral spike in their nose. After eating a package of broccoli sprouts every day, however, our body is able to keep the virus in check, potentially offering “a safe, low-cost strategy for reducing influenza risk among smokers and other at 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 and detoxifying air pollutants throughout the rest of our body? We didn’t know, until now. Off to China, where “levels of outdoor air pollution…are among the highest in the world.” By day one, those getting broccoli sprouts were able to get rid of 60 percent more benzene from their bodies. “The key finding…was the observed rapid and highly durable elevation of 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. More on air pollution here.

I’ve been reading about the terrible effects of air pollution for a long time and I am thrilled there’s something we can do other than uprooting our families and moving out to the countryside.

For more on cruciferocity, see my videos Lung Cancer Metastases and Broccoli and Breast Cancer Survival Vegetable.

There’s a secret to maximizing broccoli’s benefits. See Flashback Friday:Second Strategy to Cooking Broccoli.

For more on Cooking Greens: How to Cook Greens and Best Way to Cook Vegetables.

What about broccoli sprout pills? See Broccoli: Sprouts vs. Supplements.

Speaking of respiratory inflammation, what about dietary approaches to asthma? Learn more:

There are sources of indoor pollution, too. See Throw Household Products Off the Scent.

There is one way what we eat can directly impact air pollution, beyond just personal protection. Check out Flashback Friday: Diet and Climate Change: Cooking Up a Storm.

In health,

Michael Greger, M.D.

PS: If you haven’t yet, you can subscribe to my free videos here and watch my live presentations:


Michael Greger M.D., FACLM

Michael Greger, M.D. FACLM, is a physician, New York Times bestselling author, and internationally recognized professional speaker on a number of important public health issues. Dr. Greger has lectured at the Conference on World Affairs, the National Institutes of Health, and the International Bird Flu Summit, testified before Congress, appeared on The Dr. Oz Show and The Colbert Report, and was invited as an expert witness in defense of Oprah Winfrey at the infamous "meat defamation" trial.

28 responses to “Combating Air Pollution Effects with Food

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  1. Good morning.

    I was wondering how Dr. Greger evaluates the quality of evidence to determine whether or not something is true. For example, let’s take the effect of HDL cholesterol on artery function.

    Let’s say two randomized controlled trials say that HDL cholesterol is NOT beneficial for artery function. However, two letters to journal editors, two prospective cohort studies, two cross-sectional studies, and two case-control studies suggest that HDL cholesterol IS beneficial for the body.

    In this case, how would Dr. Greger choose which side has more and better evidence?

    NOTE: I still very much appreciate Dr. Greger’s work. I am just curious about this as this isn’t something that was addressed in Dr. Greger’s video on how he makes his videos.

    1. Great question, Vinay! It would be interesting to better understand the evaluation process.

      One think I do notice is that Dr Greger and NF specifically state how certain foods *may* be beneficial for a specific condition, whilst the evidence starts to mount up. So in your example, I guess Dr G would discuss both sides of the HDL argument.

      1. In the case of HDL, I suspect that Dr Greger would simply rely on the analyses, assessments and conclusions reached by eg the NHLBI, AHA/ACC, the UK NICE and equivalent European bodies.

        Where he seeks to add value is in educating us about the effects of food/nutrition on these issues. Not in second-guessing basic medical science. That’s my impression anyway.

  2. Sorry for going off topic but isn’t this the anniversary of Dr. Dean Ornish’s groundbreaking study on how to prevent and reverse heart disease? The team at NutritionFacts should put something on the homepage to call it out. We should also all post something on our social media pages to raise awareness of the best lifestyle on the planet.

    Thank you for this site and all you do to provide us with the science behind healthy living.



    1. Doesn’t the Ornish program also claim to prevent/reverse diabetes? If so, since these two conditions are major risk factors for serious cases of COVID-19, adopting an Ornish diet is something that people can do to reduce the likelihood of a bad outcome from the virus. I have not seen this mentioned anywhere in the mainstream media. There, it is all about masks, social distancing and the possibility of vaccines. Revamping school lunch menus is a step that school districts could take to try to lessen the incidence of these chronic diseases among children. Changing what foods are covered by food stamps (SNAP) would also be a step in the right direction. Unfortunately there is no lobby for healthful eating.

      1. Caroline,

        I agree with you. But most people don’t. I haven’t been successful in getting anyone to change their eating habits. (Well, except for my husband, since he eats my cooking; anything that he doesn’t have to prepare himself is fine by him.) Have you been persuasive to anyone?

        My brother did reverse his T2 diabetes and his high cholesterol, and lowered his BP, (as well as losing about 70 lbs) after starting to eat whole plant foods (avoiding animal products and processed foods; he also avoids added sugar, oil, and salt) and starting to exercise (his heart attack was his wake-up call). But even he can’t persuade anybody else to change their lifestyle — not even a friend of his, seriously overweight with T2 diabetes, who had at least one foot amputated a year or two ago.

        So all the information in the world, even examples people know and can see to be true, won’t change people’s habits. I wonder what motivates anybody to change.

        Oh, and there’s the added health reason to avoid meat: the way we raise our food animals is a Petri dish for future pandemics.

  3. Only two cups of broccoli a day? Are you kidding? Do you realize how much broccoli that is? I get broccoli almost every day in a green salad and I doubt there’s even a cup of broccoli in my salad – and there is plenty present.

    Years ago a physician recommended I add flax seed meal to my diet to increase fiber consumption. When I explained that I ate a large green salad daily – with broccoli, he replied that I’d need to eat a wheelbarrow full of broccoli daily.

    So, let’s try and get real about how much of a particular substance has health benefits. For starters, most people aren’t even going to eat broccoli. If they do consume it, their intake will be far less than the 2 cups recommended amount.

    It would possibly be a “good thing” if everyone were a vegan – but that’s not going to happen – for a very, very long time.

    1. I agree. However, I’m wondering about using sprouts instead of the stalks. He mentions sprouts are highly concentrated with the enzymes and it seems like putting a half cup of sprouts on a salad would be easier to handle, if that would be enough. Also, you could grow your own!

      1. Skippy,

        Yes, 2 tablespoons of broccoli sprouts were the equivalent of 2 cups of broccoli, in the Autism study.

        Plus, it doesn’t all have to be broccoli. A lot of people are eating cauliflower in many forms nowadays. Cauliflower, cabbage, Kale, broccoli microgreens, etc.

        I would struggle if it only could come in the form of broccoli, but I didn’t struggle so much with the 2 tablespoons of broccoli sprouts and I was ALSO eating a box of kale per day and some cabbage and I like cauliflower with the cheeze sauce.

        I also find it way easier to eat the microgreen forms of things like broccoli. Even if I had to eat 2 cups per day of those, they are smaller and easier to eat.

  4. I am going way out of topic here but I need to vent my frustration. I just received an FDA alert today that Ocean Spray and other companies may make certain health claims on their cranberry-based products. The FDA must be getting some funding from those manufacturers as “inconclusive, inconsistent and limited scientific studies” should not allow for health claims of any kind, period. Please read

    Sorry again for the intrusion.

    1. From the letter you posted:

      “ Based on the FDA’s review, the agency concluded that there is limited and inconsistent credible scientific evidence to support a qualified health claim for the consumption of cranberry juice beverages and limited credible scientific evidence to support a qualified health claim for the consumption of cranberry dietary supplements and a reduced risk of recurrent UTI in healthy women.”

      The “qualified statements” allowed (is that what “included in the FDA’s letter of enforcement discretion:“ means?) all include the phrase “limited and inconsistent credible scientific evidence” support the claim.

      “ For cranberry juice beverages
      “Limited and inconsistent scientific evidence shows that by consuming one serving (8 oz) each day of a cranberry juice beverage, healthy women who have had a urinary tract infection (UTI) may reduce their risk of recurrent UTI. …” [oh, wait, the word “credible” was left out; I wonder why?}

  5. Dr. Greger,

    Would you consider providing a two or three word synopsis at the top of every video and blog. Today’s would say, “Eat Broccoli.”

    1. I don’t think the intent of Dr. Greger’s thorough research is to give two-three word punch lines, like “EAT BROCCOLI!” I agree, as I’m reading through the carefully sifted empirical evidence by him and his crew, I’m searching for the main message too. But if they did that, they would be just like the thousands of glossy magazines and books on the shelves that take all the science and try to suggest that just doing this one thing will protect you from A,B, and C. The most important sentence in this article IMO is the listing of all the vegetables in this category, like kale, cauliflower, etc. My suggestion is to simply measure out how many cups of cruciferous vegetables you currently are getting in then try increasing that with as much diversity as possible. If you focus on 2 or 5 cups of broccoli every day (Or anything that specific) you’ll eventually hit a wall and entirely give up. Make broccoli pizza crust, put a cup of kale in your smoothie, throw some sprouts on your salad…

  6. Eating broccoli sprouts seem to be the answer. However I believe this is not without risk as the seeds carry pathogens which are not washed away using just water but are only killed during cooking. Would cooked sprouts carry the same health benefits?

      1. I think I found my own answer finally from the study where they put the flu virus in people’s noses with broccoli sprouts vs. alfalfa sprouts. It was a lot more than I expected:

        “Preparation of sprout homogenates
        BSH shakes were prepared similarly to a previously published method [16]. One daily “dose” was 200 grams of BSH,containing approximately 111 grams fresh sprouts (about one 4-ounce package of Broccosprouts (Brassica Protection Products LLC)). The homogenates wereprepared by our clinical/translational research center’sNutrition Research and Metabolism Core, and were homogenized with water using a ratio of 1∶1.2 in a clean blender. The same weight of alfalfa sprouts, which contain minimal SFN, was prepared in an identical manner for the placebo (ASH) treatment.”

  7. ** Could Eating Fish Protect the Brain from Air Pollution?

    According to a study in the journal Neurology (July 15, 2020), women who eat one or two servings of fish or shellfish a week have less brain shrinkage.

    The researchers recruited 1,315 women between 65 and 80. The volunteers filled out questionnaires about their dietary habits. In addition, the researchers took MRI pictures of their brains and analyzed their blood. Moreover, based on the participants’ addresses, the scientists also calculated exposure to fine particles from air pollution. Usually, increased fine particle exposure is toxic to neurons.
    Indeed, the analysis shows that women exposed to the most air pollution had less white matter in their brains. However, those who had the highest levels of omega-3 fatty acids in their blood had significantly less brain shrinkage than their peers who ate less fish.

    Consequently, the researchers suggest that eating fish once or twice weekly could help protect the brain. Fried fish did not count, because frying degrades the omega-3 fatty acids. Instead, they looked at baked or broiled fish, tuna casserole, tuna salad or other forms of canned tuna.

    ** Human brain Mapping:

    ** People Who Eat Fish Seem to Age Better:

    Results from a study of more than 2,600 older Americans suggest that diets rich in fish and shellfish containing omega-3 fats can help people stay healthy as they age (The BMJ, Oct. 17, 2018). The study started in 1992 and lasted until 2015. Blood levels of omega-3 fats were measured at the beginning of the study, after six years and at 13 years.

    People with the highest levels of seafood-derived fats were significantly less likely to develop chronic disease. They were also less susceptible to cognitive or physical impairment. As an observational study, this cannot prove that omega-3 fats are protective, but these data are certainly suggestive.

    1. Those studies appear to show that fish is a better source of calories than meat, eggs, dairy and refined carbs. You won’t get any argument from me there.

      But those aren’t the only choices we have are they Greg?

      Dr Greger recommends getting marine omega 3 fats from the original source – algae – not a middleman like fish.

      He also recommends getting omega 3s from flax seeds

      Among other problems, he has noted the increased risk of type 2 diabetes associated with fish consumption

  8. How big was the packet of broccoli sprouts they ate daily? What weight of sprouts per day does the science support?

    Any idea what the effective compound ie
    The broccoli sprouts should be effective after steaming?

  9. I enthusiastically said to myself: “Finally an article that doesn’t confound air pollution and climate change !”

    Until I read this at the end of the article:

    “There is one way what we eat can directly impact air pollution, beyond just personal protection. Check out Flashback Friday: Diet and Climate Change: Cooking Up a Storm.”

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