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Preventing Parkinson’s Disease With Diet

Low levels of neurotoxic chemicals in cheese may explain the connection between dairy product consumption and Parkinson’s disease.

March 1, 2013 |
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Supplementary Info

Sources Cited

J. Bronstein, P. Carvey, H. Chen, D. Cory-Slechta, D. DiMonte, J. Duda, P. English, S. Goldman, S. Grate, J. Hansen, J. Hoppin, S. Jewell, F. Kamel, W. Koroshetz, J. W. Langston, G. Logroscino, L. Nelson, B. Ravina, W. Rocca, G. W. Ross, T. Schettler, M. Schwarzschild, B. Scott, R. Seegal, A. Singleton, K. Steenland, C. M. Tanner, S. Van Den Eeden, M. Weisskopf. Meeting report: Consensus statement-Parkinson's disease and the environment: Collaborative on health and the environment and Parkinson's Action Network (CHE PAN) conference 26-28 June 2007. Environ. Health Perspect. 2009 117(1):117 - 121

M. A. Kamp, P. Slotty, S. Sarikaya-Seiwert, H.-J. Steiger, D. Hänggi. Traumatic brain injuries in illustrated literature: Experience from a series of over 700 head injuries in the Asterix comic books. Acta Neurochir (Wien) 2011 153(6):1351 - 5 - discussion - 1355

J. M. Hatcher-Martin, M. Gearing, K. Steenland, A. I. Levey, G. W. Miller, K. D. Pennell. Association between polychlorinated biphenyls and Parkinson's disease neuropathology. Neurotoxicology 2012 33(5):1298 - 1304

H. Arguin, M. Sánchez, G. A. Bray, J. C. Lovejoy, J. C. Peters, R. J. Jandacek, J.-P. Chaput, A. Tremblay. Impact of adopting a vegan diet or an olestra supplementation on plasma organochlorine concentrations: Results from two pilot studies. Br. J. Nutr. 2010 103(10):1433 - 1441

C. Allison Russo, Claudia Steiner. Hospital Admissions for Traumatic Brain Injuries, 2004. HCUP 2007 27(NA):1-9

J. R. Richardson, S. L. Shalat, B. Buckley, B. Winnik, P. O'Suilleabhain, R. Diaz-Arrastia, J. Reisch, D. C. German. Elevated serum pesticide levels and risk of Parkinson disease. Arch. Neurol. 2009 66(7):870 - 875

Milber JM, Noorigian JV, Morley JF, Petrovitch H, White L, Ross GW, Duda JE. Lewy pathology is not the first sign of degeneration in vulnerable neurons in Parkinson disease. Neurology. 2012 Dec 11;79(24):2307-2314. Epub 2012 Nov 14.



Four things we can do that may reduce our risk of developing Parkinson's disease is exercise, avoid dairy products and pesticides, and avoid getting hit in the head, which means wearing your seatbelt and bike helmets. And, if you read journal articles written by medical researchers with way too much time on their hands, avoid getting attacked by extraterrestrials, a leading cause of traumatic brain injury in… comic books. What about avoiding pesticides and other industrial pollutants? A recent autopsy study found higher levels in the brains of Parkinson's victims of certain PCBs found in Monsanto's Aroclor, which was banned in 1979. And the more PCBs found in the brain, the worse the brain damage. The worse three appeared to be PCBs 138, 153, and 180, all of which are significantly lower in the bodies of those eating plant-based diets. So, does a vegan diet reduce risk of Parkinson's disease? Good question. Well we know that every single prospective study on "dairy products or milk" and Parkinson's disease found increased risk. And again it may be that dairy products in the United States are contaminated with neurotoxic chemicals. There's substantial evidence "suggesting that exposure to pesticides may increase Parkinson’s disease risk," and autopsies have found higher levels of pollutants and pesticides in the brains of Parkinson’s disease patients, and some of these toxins are present at low levels in dairy products. They're talking about toxins like tetrahydroisoquinoline, a parkinsonism-related compound found predominantly in cheese. Although the amounts of this neurotoxin—even in cheese—are really "not very high," the concern is that the chemical may accumulate in the brain over long periods of consumption. 

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Jonathan Hodgson.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

Here's the link to that video documenting the levels of PCBs in the bodies of those eating plant-based diets: Industrial Pollutants in Vegans. If this bit sounds familiar, it's because I featured it in my 2012 year in review Uprooting the Leading Causes of Death. I also touch on Parkinson's in Risk Associated With Iron SupplementsAvoiding Other Banned Pesticides, and Industrial Carcinogens in Animal Fat.

Avoiding dairy may have other benefits. See, for example:

Or any of my other 73 videos on dairy.

What if it's too late and you or a friend or family member already have Parkinson's? Treating Parkinson's Disease With Diet is coming up next!

For some context, please check out my associated blog posts: Avoiding Dairy to Prevent Parkinson's and Treating Parkinson's Disease with Diet

If you haven't yet, you can subscribe to my videos for free by clicking here.

  • Janet Weeks V

    Thank you, Dr. Greger.

    • Michael Greger M.D.

      You are welcome Janet!

  • Jan Carrie Steven

    Thank you for this. I would love to know if there is any connection between ALS and mad cow.

    • Michael Greger M.D.

      Not mad cow, but I do have an ALS video coming up — stay tuned! Make sure you’re subscribed so you don’t miss it:

  • Veggie247

    I assume most vegans in the U.S. probably adopt veganism in adulthood after some period of consuming dairy and meats. It would be interesting to know how reversible the effects of earlier meat and dairy consumption are. For example, if one eats meat and dairy until age 30 and then eats vegan thereafter, what does the risk for Parkinson’s and other chronic diseases like cancer look like compared with those who eat meat and dairy for life and those who have been vegan all of their lives or most of their lives? How does that differ from conversion at age 50 to a vegan diet? And so forth…

  • beetsbeansbutts

    Interesting video! Thanks!

  • Nibiskusse

    If Parkinson’s disease may partly be triggered by pesticides, shouldn’t we worry more about our fruit consumption (especially if we eat lots of them, especially those most exposed to pesticides) than our cheese consumption?

    • Thea

      Nibiskusse: Good question.

      It never hurts to eat organic. But what we know about food contaminants is that they get concentrated the more you move up the food chain. So, if you think a fruit or grain might be bad, it’s worse with dairy or other animal products because cows eat plants and then we eat cows…

      That’s the idea. This video holds up this theory pretty well – at least on the surface: since people eating a plant-based diet had fewer of this pesticide in their bodies compared to the dairy eaters.

      Hope that helps.

  • albert

    I thought Parkinson is considered to possibly be of inflammatory origin ( If it could be the case then anti-inflammatory tactics should apply – just again. Also I was wondering if coffee might have a positive effect as in case with Alzheimers…

    • cheneval

      coffee ,tea,pepper,ok

  • Nicole

    Monsanto is headquartered in St Louis, where I know of a lot of people who developed Parkinson’s. That would be an interesting study to see if the cluster relates to the proximity to Monsanto.

  • Dar Dobs

    lest we forget:’Michael Fox *** Parkinson’s and Aspartame’
    By Betty Martini

  • Darryl Roy

    Curiously, Parkinson’s is the one major disease where biomarkers of animal product consumption (serum cholesterol and uric acid) appear associated with lower risk and disease progression (PMIDs:16905642, 17954784, 17177184, 18975349, 20945982, 21853051), to the extent that diagnosed gout is protective.

    Current speculation seems to be that the high uric acid is acting as a CNS antioxidant (PMID:20061611), which, unlike the abundant antioxidants in a whole plant foods diet, can easily pass the blood-brain barrier (PMIDs: 11406187, 19721819).

    There’s seems a lot of work on attaching plant antioxidants to nanoparticles to improve their penetration of the blood-brain barrier (one example: PMID 23229335) for Parkinson’s and Alzheimer’s therapy.

    There are a few high purine vegan foods (nutritional yeast & Porcino mushrooms) that one could theoretically induce gout with, but that seems a poor option. I think my project this week will be scouring the literature for vegan antioxidants that pass the blood-brain barrier.

    • Thea

      re: ” I think my project this week will be scouring the literature for vegan antioxidants that pass the blood-brain barrier.”


      Feel free to share!

      • Darryl Roy

        Apologies for the delay.

        The direction to pursue is not dietary antioxidants, but the brain’s own antioxidants like glutathione, available in concentrations thousands of fold greater. Its useless as a supplement (its digested), but you can induce its production, as well as that of hundreds of other cytoprotective and repair enzymes. Known inducers of the neuronal adaptive stress response include:

        resveratrol (red grapes & wine)
        sulforaphane (broccoli & other cruciferous vegetables)

        curcumin (tumeric)

        catechins (green tea)

        allium & allicin (garlic & onions)

        hypericin (St John’s wort)

        Does that list sound familiar? It should, and this beautifully written review may explain the mechanism behind many the videos on this site.

        Mattson, Mark P., and Aiwu Cheng. “Neurohormetic phytochemicals: Low-dose toxins that induce adaptive neuronal stress responses.” Trends in neurosciences 29.11 (2006): 632-639.

        Not related to antioxidants, per se, but caffeine is known to reduce risk for Parkinson’s disease, and we’re beginning to know why. It blocks adenosine A1 and A2A receptors on microglia, thereby preventing chronic inflammation:

        Brothers, Holly M., Yannick Marchalant, and Gary L. Wenk. “Caffeine attenuates lipopolysaccharide-induced neuroinflammation.” Neuroscience letters 480.2 (2010): 97-100.

      • Darryl Roy

        Sorry for the delay:

        A growing body of evidence indicates that consuming large quantities of antioxidants like vitamin C, E, and β-carotene can interfere with the body’s endogenous antioxidant system.

        The effective mechanism of phytochemicals like the polyphenols isn’t through augmenting the body’s antioxidants. For one, obtainable tissue concentrations are only 2-4% those of endogenous antioxidants (uric acid, glutathione, bilirubin). The most effective phytochemicals appear to work by inducing the Keap1/Nrf2/ARE pathway modulated Adaptive Stress Response, and they do so through reacting with sulfhydryl groups on Keap1 in pro-oxidant ways.

        The Adaptive Stress Response includes well over 100 cytoprotective proteins that participate in production of endogenous antioxidants, DNA & protein repair, damaged protein removal, toxin export, metal chelation, inflammation inhibition, or are themselves antioxidants. Small stressors like phytochemicals, exercise, or calorie restriction can elevate basal levels of the Adaptive Stress Response for days, while large doses of more bioavailable exogenous antioxidants (C, E, β-carotene) appear to suppress it.

        Some phytochemicals that have demonstrated protective effects in both tissue culture and animal models of Parkinson’s and neurodegenerative disease through the Keap1/Nrf2/ARE pathway include:

        sulforaphane (broccoli esp sprouts, cabbage, kale and other cruciferous vegetables)
        curcumin (tumeric)
        epigallocatechin gallate (green tea)
        resveratrol (grapes
        allicin (garlic)
        hypericin (St. John’s wort)
        carnosic acid (rosemary)
        luteolin (thyme, oregano, rosemary, pepperment, chamomile, olive oil, and others)

        There’s evidence that ingesting multiple inducers has synergistic effects. Many other phytochemicals appear to act via the same mechanism, but haven’t been investigated in studies of neurodegenerative disorders.

        Carnosic acid from rosemary is particularly interesting to me, as it occurs at high natural concentrations (1-2% of fresh leaf, 5% of dried), has high bioavailability unlike some (eg curcumin or resveratrol), readily passes through the blood-brain barrier, and appears understudied.

        Further reading:

      • Darryl Roy

        Sorry for the delay – this is a synopsis of some of my reading over the past month touching on the subject – many of my uncritical assumptions were challenged.

        The effective mechanism of phytochemical “antioxidants” like the polyphenols is probably not through augmenting the body’s antioxidants. For one, obtainable tissue concentrations are only 2-4% those of endogenous antioxidants like uric acid, glutathione, and bilirubin. Moreover, reactive nitrogen and oxygen species (RNOS) are used extensively in cellular signalling, and cells adaptively regulate endogenous antioxidants on short time scales to respond to deletorious spikes of RNOS faster than we could ever achieve with dietary antioxidants. A growing body of evidence indicates that consuming large, supplemental doses of exogenous antioxidants like vitamin C, E, and β-carotene can interfere with the body’s endogenous antioxidant system.

        Rather, some of the most effective phytochemicals appear to work via the PRO-oxidant reaction of their quinone metabolites with thiols on the sensor protein Keap1, releasing the transcription regulator Nrf2 into the nucleus to initiate an adaptive stress response. This adaptive stress response includes well over 100 cytoprotective proteins that participate in production of endogenous antioxidants, DNA & protein repair, damaged protein removal, toxin export, metal chelation, inflammation inhibition, or are themselves antioxidants. Small stressors like phytochemicals, exercise, or calorie restriction can elevate basal levels of the adaptive stress response proteins for days, while large doses of the more bioavailable exogenous antioxidants like vitamin C, vitamin E, and β-carotene suppress their levels.

        Some phytochemicals which induce the Keap1/Nrf2 pathway and have demonstrated protective effects in both neuron tissue culture and animal models of Parkinson’s and neurodegenerative disease include:

        • sulforaphane (broccoli, cabbage, kale and other cruciferous vegetables)
        • curcumin (tumeric)
        • epigallocatechin gallate (green tea)
        • resveratrol (grape skins)
        • allicin (garlic)
        • hypericin (St. John’s wort)
        • carnosic acid (rosemary)
        • luteolin (thyme, oregano, rosemary, pepperment, chamomile, olive oil, and others)

        Many other phytochemicals appear to act via the same mechanism, but to my knowledge haven’t been investigated in studies of neurodegenerative disorders.

        There’s evidence that ingesting multiple adaptive stress response inducers has synergistic effects, and some whole plant extracts are considerably more potent inducers than pure compounds. Phytochemical cocktails may be interacting with multiple regulatory pathways upstream of Nrf2, and their various metabolites may react with different cysteine redox “sensors” on Keap1.

        Caffeine, functioning as an A2A adenosine receptor antagonist, also appears protective against Parkinson’s and other neurodegenerative diseases. Its believed that chronic inflammation has a role in dopaminergic neuron death in Parkinson’s, and blocking the A2A pathway attenuates these inflammatory responses.

        Some further reading:

        Plant-derived compounds as antioxidants for health–are they all really antioxidants?
        Modulation of Nrf2/ARE pathway by food polyphenols: a nutritional neuroprotective strategy for cognitive and neurodegenerative disorders”
        Neurohormetic phytochemicals: low-dose toxins that induce adaptive neuronal stress responses
        Nrf2 as a Master Redox Switch in Turning on the Cellular Signaling Involved in the Induction of Cytoprotective Genes by Some Chemopreventive Phytochemicals
        Cellular stress responses: hormetic phytochemicals and vitagenes in aging and longevity
        Caffeine Exposure and the Risk of Parkinson’s Disease: A Systematic Review and Meta-Analysis of Observational Studies.
        Neuroprotection by caffeine and A (2A) adenosine receptor inactivation in a model of Parkinson’s disease.

  • Elaine Wilhelm

    Nothing seems to be safe to eat these days!

  • Gustavo Zaera Holo

    Thank you for this video and a generally great website.

    I’ve been watching quite a few videos over the last month, and I often question the quality of the animal products that are consumed. Is there a difference in the health issues put forward here, if one consumes organic diary products instead? What about organic meat? I am convinced that the meat, egg and diary industry in the USA in general pushes products of low quality, but does that mean that meat, eggs and diary are bad for you no matter what?

  • Tonya CatLady

    Thank you for clarifying that cheese does more harm than just clog
    arteries and cause fat. We know dairy causes cancer, Harvard has finally
    come out publicly to say milk is bad for human health. Dairy contains
    cruelty, blood and puss and is just GROSS. My father had Parkinson’s and
    I always thought it was caused by chemicals like pesticides as you
    describe, maybe fluoride and leads in the water, and also too much
    animal protein (animal flesh) in the brain causing it to misfire, and
    now I know dairy/cheese was a culprit too. Sad!

    I am vegan for
    my health to prevent cancer, dementia, stroke, heart attack, high blood
    pressure, or any other illness, and also after learning about how
    horribly barbaric farm animals are tortured daily to produce meat and

    • Tonya CatLady

      It’s so easy to switch to plant-based dairy like almond milk, soy, coconut milk, etc. Also vegan cheeses taste great and it takes 5 minutes to make cheeses like cream cheese, blue, sharp cheddar, etc. Simply no reason to eat dairy cheese that causes cancer, etc.

      Anyone can watch FORKS OVER KNIVES and FARM TO FRIDGE online to educate yourselves about how the food supply is killing people in epidemic proportions, and also the horrific cruelty to animals at ALL farms, not just factory farms. Time for citizens to EVOLVE and learn what you are “really” swallowing. Death and tortured souls. Not cool.

  • lgking

    My now deceased father-in-law who was born in Vietnam (in 1929) and was raised and lived in northern Thailand the remainder of his life, was extremely physically active…had virtually no dairy in his diet his whole life. And, was diagnosed in his last 25 years with Parkinson’s disease.

  • Ronald Chavin

    Tea drinkers in China had a lower risk of developing Parkinson’s than coffee drinkers in China:
    To block the absorption of toxic heavy(?) metals (arsenic, lead, mercury, cadmium, barium, beryllium) and industrial pollutants (PCBs, etc.), eat foods that are high in phytate such as wheat bran, fenugreek seeds, natto, edamame, TVP (soy meat), green peas, common beans, almonds, ground flaxseeds, chia seeds, etc. Phytate also partially blocks the absorption of iron, which like copper, manganese, and aluminum, is a pro-oxidant which, in excess, will damage every cell in our bodies. On the downside, phytate also partially blocks the absorption of zinc, which like selenium and iodine, is a beneficial antioxidant.

    • Ronald Chavin

      That study on Parkinson’s involved Chinese in Singapore, not Chinese in China. Also, note that Parkinson’s was shown in that study to be a comorbidity of heart disease. Other comorbidities of heart disease and stroke include gum disease, osteoporosis, Alzheimer’s, and many cancers. If you already suffer from any one of these diseases, you are at high risk of developing many of the others. The good news is that we can prevent all of the above diseases by preventing heart disease. How? Eat a plant-based diet that is high in marine omega-3s, vitamin B12, vitamin K2/MK-7, and vitamin D.

  • marvin

    Yet another reason to give up dairy, as if we don’t already have enough. Ethical vegans like me can file this little detail away to add to the growing mountain of health related concerns related to dairy. It’s always nice to have a ton of compelling facts at hand when trying to overcome the on going propaganda campaign designed to further the absurd idea that milk his healthy. The irony of this is; so much time and energy is put into marketing a product which common sense should dictate was never intended for humans, especially adult humans.

  • Mindaugas Raulinaitis

    Except for organochlorine compounds, the vegetarian population may be more exposed to pesticide residues than the general population due to specific dietary habits. Thus, this population should be considered for risk assessment of pesticide residues.

    Food Addit Contam Part A Chem Anal Control Expo Risk Assess. 2009 Oct;26(10):1372-88. doi: 10.1080/02652030903031171.

    Impact of food consumption habits on the pesticide dietary intake: comparison between a French vegetarian and the general population.

    Van Audenhaege M1, Heraud F, Menard C, Bouyrie J, Morois S, Calamassi-Tran G, Lesterle S, Volatier JL, Leblanc JC.

    • Toxins

      Vegetarians still consume dairy and eggs, but even looking at conventional fruit and veggies, here are Dr. G’s opinions.

      “A new study calculated that if half the U.S. population ate just one more serving of conventional fruits and vegetables, 20,000 cases of cancer could be prevented. At the same time the added pesticide consumption could cause up to 10 extra cancer cases. So by eating conventional produce we may get a tiny bump in cancer risk, but that’s more than compensated by the dramatic drop in risk that accompanies whole food plant consumption. Even if all we had to eat was the most contaminated produce the benefits would far outweigh any risks. Having said that, why risk any bump at all? That’s one of the reasons I encourage everyone to choose organic whenever one can, but we should never let concern about pesticides lower our fruit and vegetable consumption.”

  • Emma Gurashi Nikolaoy

    Dear Dr,Grager..iam so thankful for that amazin lessons you doing here…also i read so much your page and many times i said how right you have for that amazing informations…i wish with my heart good job all do u do…Dr Emma…Athens

  • Theo Gregoire

    Dr Greger,

    May I first start by saying you are an absolute blessing for your dedication to providing humanity with the information that you do. And I thank you.

    May I ask what your advice would be for administering an whole food plant-based diet to someone who has dysphagia and takes nutrition supplements via NG tube as a result, would be?

    My mothers diet consisted of regular fried (palm oil, corn oil, sunflower oil, etc) foods, chicken, white rice, eggs, milk, etc etc, which eventually led her to being prescribed statins (Lipator), which over time eventually lead to her being diagnosed as having “parkinson’s”. Oh and in between the statin prescription and parkinson’s diagnosis, she had a stroke The time scale from being prescribed statins to being ‘diagnosed’ with parkinson’s is some 5-6 years, with the stroke being some 2 or so years ago now.

    The material that I have researched, from both yourself and Dr. McDougall, leads me to the firm conviction that her diet has led her to where she is now.

    Can you please advise.

    Many thanks in advance,

    • Thea

      Theo, I’m so sorry to hear about your mother’s situation. It’s such a sad story, and I’m sorry for all of you.

      I hope that Dr. Greger or someone else may be able to advise you. But I wanted to let you know that Dr. Greger doesn’t generally participate on these forums any more. I’m guessing he just can’t with his schedule. Hopefully someone else will jump in. I would recommend that you see if you can find a doctor in your area who really understands nutrition and can help. I know that there are doctors out there who follow the NutritionFacts site. Perhaps one in your area can help.

      Good luck.