Doctor's Note

More on preventing allergic diseases can be found in my videos Preventing Childhood Allergies and Preventing Allergies in Adulthood.

More on protecting lung function with fruits and vegetables can be found in Preventing COPD With Diet.

Surprised probiotics can affect immune function? Check out my video Preventing the Common Cold with Probiotics? And if you think that is wild, wait until you see Gut Feelings: Probiotics and Mental Health.

What might be in plants that’s so beneficial? See Anti-inflammatory Antioxidants.

What might be in animal products that is harmful to lung function? There are endocrine-disrupting industrial pollutants that build up in the food chain that may be playing a role. See my videos Alkylphenol Endocrine Disruptors and Allergies and Dietary Sources of Alkylphenol Endocrine Disruptors. Also there’s an inflammatory omega-6 fatty acid found predominantly in chicken and eggs that may contribute to inflammation as well. See Inflammatory Remarks About Arachidonic Acid.

Choosing fragrance-free personal care products may also help reduce airway reactivity: Throw Household Products Off the Scent.

If fruit and vegetables are so powerful at preventing allergic diseases, what about treating allergies with plants? Coming right up! My next video is Treating Asthma With Fruits and Vegetables. Then I compare the efficacy of plants to pills (Treating Asthma With Plants vs. Supplements?) and close out this video series exploring the role an entire diet filled with plants might play in Treating Asthma and Eczema With Plant-Based Diets.

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  • BeetsBeansButts

    I expected air pollution to be easily more correlated with asthma than diet.

    It’s much easier for me to eat healthy than to move the freeway that is next to my house.


    • masobel

      Air pollution certainly has an effect on asthma. But Harvard did a large study that found that areas that had improved air quality in the past decade still had increasing rates of asthma. They linked the increased incidence of asthma to the increase in obesity rates since obesity is also a risk factor for asthma.

      • cpmt

        hummm food we eat (most of it are GMO’s : sugar in everything, { & sugar, wheat, soy, corn etc…in all foods we buy} 96-to-98% are GMO

    • nia feht

      Look into plants that purify the air, a lot of the easy to grow stuff like spider plants are good :)

  • alice

    I have had asthma for over 45 years which I’ve managed with daily doses of Advair, supplementing with an Albuteral inhaler when needed. Before using Advair I would get daily asthma “attacks” triggered by dust, mold, animals (cats and dog dander), exercise, laughing, cold weather,… I never went anywhere without an inhaler. Several years ago I started drinking green smoothies daily, that had a lot of spinach, kale, chard, etc., in them. After about 6 months I tried going off my Advair to see how my asthma was fairing. No asthma! It had disappeared! I had tried going off of my asthma meds periodically before drinking green smoothies, but the asthma was always there. So I am now completely off of asthma meds and have been all these several years. Occasionally I am not as good about drinking green smoothies, sometimes going weeks, or even a few months without drinking them, such as when on an extensive camping trip. During those times I occasionally start feeling tightening in my chest, like there is a hint of the asthma coming back. I then pay extra attention to drinking the smoothies and eating more greens and fruit. I am a scientist and don’t go in for many miracle cures or improved health claims unless there is a study to back it up. Green smoothies, however, certainly changed my life.

    • DGH

      I was wondering what you put in your smoothies. I don’t have asthma. I seem to have a major gastrointestinal intolerance to kale, however.

      • Coacervate

        Yes I too would like to try that smoothie…FWIW, my good friend also had intolerance to kale (and other green leafies) but was able to adjust by starting with just a single teaspoon included in soups, salads…then slowly increased the amount over a couple of weeks …anyway he is now able to eat full servings without the gas and other problems that he used to have. Just a thought

        • DGH

          Thanks but it wasn’t gas. The first time I tried kale was the last time I will try kale … I got 5 days of severe diarrhea and foul-smelling eructation (burps) … this was a combination of steamed and fresh kale. I am reluctant to ever go near this again. From what I have read on the internet, stories like mine are common with kale and it could be an immune-mediated reaction (true allergy).

          • Coacervate

            Bummer…just wondering: do other cruciferous veg cause a similar reaction or just the Kale?

          • DGH

            Just kale, but I have not tried very closely related species like collards, mustard greens, swiss char. No problems whatsoever with broccoli, cabbage, cauliflower. I do wonder if my problem was just bad food poisoning, but I am unwilling to risk trying again – it was so bad!

          • mbglife

            I always wake up in the middle of the night while my eyes are still closed. I’ve noticed on nights when I have eaten kale that I have an erratic light pattern going in my mind. I’m assuming it’s a form of ocular migraines (no pain with mine) that I get if I eat bananas. I’ve also noticed that on days when I eat bok choy the same thing happens but the light pattern is different, not erratic. Nothing happens to me when I eat broccoli or cauliflower, but if I eat more than a few servings a week of cauliflower, I get dizzy and feel very unwell. Something similar happens to me when I take more than 1/2 tsp of turmeric in a week. It took me awhile to figure all of this out, but lots of people have unique allergies and sensitivities. BTW, I still choose to eat some kale and bok choy weekly, but I only eat bananas a few times a year.

          • DGH

            I stopped eating broccoli raw because I was getting thyroid issues (fatigue and cold intolerance). At the same time, I stopped eating cabbage and cauliflower raw.

          • mbglife

            I should have been clearer in my response. I never eat those veggies raw, only cooked, which eliminates the possible negative affect on the thyroid.

          • Thea

            mbglife: That’s really interesting. I’ve never heard of that. Good for you for figuring it out.

          • satch

            I too have had odd reactions to kale and bok choy. I avoid them now. My guess is that certain greens contain high amounts of anti-nutritients (plants don’t actually want to get eaten, they don’t exist for us, they exist for themselves).

            Bananas cause me heart palpitations.

          • cpmt

            they have oxalic acid with intefiere with thyroid hormones. They recommend (if you are not sensitive ) to eat only small quantities.

          • cpmt

            did you try oven roasted and crisp kale? try just a little bit to see if you have the same reaction. I think they bake it in a low oven so good nutrients are Not destroyed.

    • JacquieRN

      Wow, thank you for sharing that story. Please do share your “recipe”.

    • cindy

      Alice, thank you for sharing your story! I have developed adult-onset asthma from working in old, poorly ventilated buildings, and have been prescribed Advair and told to take it for the rest of my life. I asked about whether dietary changes could help with the symptoms, and the pulmonologist said “no”. But so much research suggests otherwise, and your story gives me hope. I’ve already started making dietary changes (eating more fruit, cutting back on dairy and eggs), and based on what you said I’m going to try adding green drinks. When I take a week off work, my symptoms gradually get better, so I think the symptoms will go away when I find a different job. In the meantime, I’m hoping a healthier me will emerge. I’m glad you’re off the Advair!

      • alice

        I wrote about what I include in my smoothies in a comment above. In response to your comment, I do think that eating lots of fruit and veggies probably helps with your asthma, but I’ve always liked to eat veggies, and I still had asthma. I wonder if grinding the greens, fruits, and veggies in the blender makes more micronutrients more available for our bodies to absorb and breaks down the fibers into smaller bits for bacteria in the gut to digest. I recently saw an article in the newspaper about the affect increased fiber in the diet had on asthma. I found this article in a quick look on the internet
        Best of luck!

    • Peace Plants Play

      I ‘cured’ my asthma, environmental allergies and exzema of 30 + years during the third week of eliminating dairy from my diet. I know it was dairy because my symptoms returned after some greek yogurt dip. I am lactose intolerant so I have not had milk in more than 15 years, only cheese and ‘healthy yogurt’. I am disease free for more than 3 years now! No more corticosteroids, albuterol, antihistamines or lotions! I’m not even allergic to my cats or pollen and I live in a city notorius for severe pollen/allergies.
      A bit frustrating that I was being treated for symptom suppression- lung, sinus and skin inflammation and not one allergist ever suggested it might be an food allergy.
      Plant-based rules!

      • Veggivet

        Same here. My asthma disappeared after I eliminated dairy from my diet. Should have done it way before I eventually did. No longer have to carry an inhaler in my pocket.

    • Zuppkko

      Greens and fruit are good at moving lymph (sewer system), they also help regenerate tissues, support endocrine glands, detoxify … They also dont cause much mucus, like dairy does. I’m sowing greens like crazy this year. I’m going to drink some smoothies. :)

    • cpmt

      The greens you mention (organic are better) and CILANTRO & PARSLEY are great for asthma and SKIN PROBLEMS like eccema psoriasis etc.

  • Arun Mukherjee

    You suggest that there is less incidence of itchy eyes and runny noses in India (assuming that Indians consume vegetarian diets), but that is not true. Indian children are obese and suffering from all sorts of allergies.

    • Luke Davis

      Dr. Michael Greger said in the video, “Like why does the prevalence of itchy eyes and runny noses range
      anywhere from 1% in India, for example, up to 45% of kids elsewhere?
      There were some associations with regional air pollution and smoking
      rates, but the most significant associations were with diet. Adolescents
      showed a consistent pattern of decreases in symptoms of wheeze (current
      and severe), allergic rhinoconjunctivitis and atopic eczema, associated
      with increased per capita consumption of plants.”. I hope this helps! :)

      • Arun Mukherjee

        I do not dispute what Dr. Greger said. I dispute the assumption that only 1% of Indian children have itchy eyes etc. Asthma is a big problem in India.

        • Luke Davis

          Are you from India? I am curious of the age of these scientific papers. But I would have to say one thing, at the time the study was being studied it was fact.

          • Arun Mukherjee

            Yes, I am of Indian origin and visit India frequently. The medical studies done in India have come under a lot of scrutiny for unethical practices and messaging of results. In my own experience, I see my extended family’s kids as well as my my friends’ kids suffering from asthma and obesity due to processed foods and very high levels of air pollution in cities.

          • lilyroza

            India is only 50% vegetarian now, it used to be 90%, back in the 40s. I ‘ve known a lot of Indians, and my experience is that the rich Indians are not vegetarians. Bramins and Sikh tend not to be vegetarian (altho Anglo-American Sikh usually are vegetarian). Among non vegetarian Indians, they seem to prefer to fatten up the children. I have known wealthy omnivore indians to force and shame and demand that their kids eat more, from an early age. They equate fatness with wealth and a lean body with poverty. So maybe you are seeing more of the rich and omnivores’ kids and less of the poor and the vegetarian kids.

          • David

            I have been living and working in India for the past 43 years and have witnessed a transition in cities (even villages and small towns) toward more air pollution and also big dietary changes from whole grains and healthy unrefined oils to white flour, polished rice, excessive sugar and unlimited availability of milk (white revolution). There has been a transition from lower incidence of heart disease, cancer and diabetes to the mushrooming of specialty hospitals treating these lifestyle diseases (eg Apollo hospital). It has taken epidemic proportions. Also more meat is eaten. But a key point is that even vegetarian diets here in India often have over 60% of their calories by fat. (Dr Graham pointed this out in his book 801010 and when I checked it was true for the indian veg diet too)) So vegetarianism per se is not healthy…vegan is better and raw vegan is best…. Fortunately there is a naturopathic/ayurvedic tradition here and a quick cultural change back to healthier ways is possible. Watch this space.

  • Luke Davis

    I am on a plant based diet avoiding sugar and hydrogenated oils. I have been allergic to cats for a while and was wondering if it will go away under my diet. I do take ground flaxseed (ground at home) and B12/D supplements.

    • Veganrunner

      Hi Luke,
      I also am allergic to cats. After 2 years of WFPB I can now pet a cat without getting a runny nose. Not that I am willing to stick my nose in their fur but I have noticed a definite improvement.

  • DGH

    A footnote on arachidonic acid. It appears to be associated with lower coronary risk – “Among specific polyunsaturated fatty acids, eicosapentaenoic (0.78 [CI, 0.65 to 0.94]), docosahexaenoic (0.79 [CI, 0.67 to 0.93]), and arachidonic (0.83 [CI, 0.74 to 0.92]) acids were associated with lower risk. ” (Ann Intern Med. 2014;160(6):398-406. doi:10.7326/M13-1788). This is based on a meta-analysis of 10 prospective cohort studies with nearly 23,000 participants incurring 3739 coronary events. The authors conclude that “circulating levels of eicosapentaenoic and docosahexaenoic acids (the 2 main types of long-chain -3 polyunsaturated fatty acids) and arachidonic acid are each associated with lower coronary risk.”

  • Julot Julott

    All these things are secondary factors even food, the real cause(which is mechanical problems) of most asthma and similar problems included some respiratory allergies has been found by Jacques Gesret and its method 20-30 years ago, a method that completely cure it with over 90% success~

  • Tiago Cartageno

    Dr Greger fortunately I consider myself a success case in the fight against allergies and asthma. Since I was a child I had problems with these things. All my life until my 30s I fought pollen allergies all Springs having itchy eye, rhinitis and sinusitis. My mother is a doctor but to be honest she does´t know much about nutrition as well as the majority of the doctors around. So she prescribed me pills which I hate because of the side effects, and also because they didn´t prevent the problems to happen again. So 3 years ago after reading the Brendan Brazier book “Thrive” I decided to become vegetarian and I started to abolish dairy and all kind o animal products. Interestingly it was not enough to fight those problems until I have found your website, which I am truly thankful to discover. So I started to see all you videos about antioxidants and then I started to consume more often the top ones like black beans, purple cabbage, cinnamon, cloves, walnuts and all kind of berries. You can´t imagine my happiness when this year for the first time in the Spring I found myself completely free from pollen allergies. For the first time in my life I did´t need to take any antihistamine pill! It was really great to notice that food is a kind complex system that can push our bodies to great things or to bad things, depending on the things we eat. Now my asthma is practically gone also! In the past I cousin´t run in the autumn/winter because the cold weather activated my asthma. This autumn for the first time I´m realizing that my body is becoming stronger to deal with this asthma thing. Sometimes I feel kind of sad to think that my mother could´t heal me from these troubles with her prescription, but after all I see that this is a global problem nowadays with all the Doctors. I know my mother has patients with asthma and I don´t imagine her to tell them to go animal free and eat a lot of antioxidants… anyway I´m giving her some hints time to time. I hope she use them to make some life easier. Dr Greger thank you very much for your inspiration. Your knowledge doesn´t have a price for me. I watch your videos everyday to make my food more functional and is really working! Best regards.

  • cpmt

    gmo’s foods cause allergic reactions and other illnesses in children and sensitive adults.

    • Magnus

      Hi. Í´ve been wondering about treating asthma to preclude future diseases, like pneumonia. Well…thats what i am doing with my Cymbicort inhaler. I reasently visited my doctor and i asked him if i can stop taking my meds all togheter. But he recommended staying on my (4 inh. /day) dose to reduce risk of getting more problems with my lungs, in the future. But sinse the inhalations does´nt give me any reliefe, and i fear they might toxifie me more,(like most other meds do), rather then doing me any good. I´m thinking about gradually quiting (at a slow controlled pace of course). But maybe my antioxidant boost, for my immune system, trough my plant based food & large intake of berries etc. just does´nt cut it. And maybe…because it´s a “local” treatment inside the lugns, it stays there, and does´nt go in to my bloodstream. Though i find that highly doubtfull. (Any one else here using Cymbicort perhaps..?)
      And how does going vegetarian help me. Ivé tried it Before (for 42days) and my blood work was great, but as i also had a spike in Creatin Kinase (25 mkat/L CK) i was forced to go back to my regular diet. But now i´m giving it Another chance and i´m hoping the CK value, had nothing to do with the diet at the time.

      So i guess the million dollar question is..should i stay on the meds, or quit and risk getting worse symtomes.
      (And by by symtomes i don´t mean attacks, because my Asthma is at a constante reduced & irreversible state)

      (I apologize for any misspelling, but i´m not from your country, i´m from Sweden)

      Best regards… / M

  • Melody

    My asthma went away when I became a vegetarian at age fifteen. Now, I know why.

  • Melody

    My asthma went away when I became a vegetarian at age fifteen. Now, I know why.

  • fitzman

    what is the research on fermented vegetables