Are there immune-boosting foods we should be eating?
The Immune System and COVID-19 Treatment
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Though there are more than 400 clinical treatment trials underway, currently there is no specific proven therapy for COVID-19. And we should not expect a vaccine or effective antiviral drug to be available anytime soon, although we are developing COVID-19 vaccines at pandemic speed. Just for reference, the average vaccine takes more than a decade to develop, with an average failure rate of 94%.
Many have asked me for advice on what they can eat to help bolster their immune system. “How Not to Die from Infections” is, after all, the title of chapter five of my book How Not to Die, and I do have more than a hundred free videos online at NutritionFacts.org that reference immune function. And there are amazing studies, like randomized double-blind trials, showing, for example, that eating broccoli sprouts can reduce viral loads for influenza, decrease virus-induced inflammation, and boost our antiviral natural killer cell activity. Just from eating some broccoli sprouts! But this isn’t the flu.
I certainly support general, commonsense advice to stay healthy during the crisis, put forth by trusted authorities such as the American College of Lifestyle Medicine. This includes getting sufficient sleep (seven to nine hours), keeping active, reducing stress, staying connected—albeit remotely—to friends and family, and eating healthfully (a diet centered around whole plant foods)., The World Health Organization agrees: Fruits, vegetables, legumes—like beans, split peas, chickpeas, and lentils—nuts, and whole grains, cutting down on sugars, cutting down on meat, dairy, and junk, and cutting down on salt.
“Optimal Nutritional Status for a Well-Functioning Immune System Is an Important Factor to Protect against Viral Infections.” However, one must resist the urge to jump on the snake-oily spamwagon of foods to boost your immune system, given our near-total ignorance of the immunological aspects of this new disease, because enhancing specific arms of the immune system could hypothetically even make things worse. Let me explain.
Take the example of this married couple, both the same age, admitted to the hospital on the same day for the same COVID-19 infection—fever and shortness of breath. Tragically, the wife was immunocompromised, because she was on chemo for breast cancer at the time (yikes!), whereas her husband had an intact immune system. The wife did fine, though, out of the hospital in under a week, whereas the husband ended up in intensive care. Wait, the immunocompromised patient did better? How is that possible? Because unlike other common viruses, coronaviruses have not shown to cause a more severe disease in immunosuppressed patients. Why? Because your own immune response appears to be the main driver of lung tissue damage during infection.
Starting around the second week of symptoms, the virus can trigger what’s called a cytokine storm. It’s like an autoimmune reaction where your body over-reacts, and in attacking coronavirus, your lungs get caught in the crossfire. In the first week of the illness, it’s the virus itself that’s triggering most of your symptoms, but then in severe cases, it’s our own inflammatory response that takes over in causing most of the damage. It’s striking that many of our innate immune-signaling pathways, these cytokine chemical messengers our immune cells release, is aimed at killing off our own cells. But that makes total sense. The virus turns our own cells against us into little virus factories, so it’s part of our own antiviral defense to kill off our own cells to dead-end viral replication. Viruses can’t replicate in dead cells, so cell suicide is like a way to create firebreaks. But in burning down the village in order to save it, we may not survive the process.
This has led some to consider immunosuppression as a treatment for severe COVID-19, but of course immunosuppression for hyperinflammation in COVID-19 might be a double-edged sword. So, when you see that broccoli sprouts can whip up natural killer cell activity within two days, is that a good thing or a bad thing for COVID-19? It was good for seasonal flu, but who knows with this new coronavirus.
Young children have relatively immature immune systems, and normally suffer disproportionally from viral infections such as the flu––but not, apparently, from COVD-19 or SARS or MERS, for that matter, the other two deadly coronaviruses. It’s interesting; one theory as to why children seem protected suggests that greater pre-existing exposure to common-cold coronaviruses offers kids some cross-protection against the new virus. But ironically, a competing theory suggests it’s their lack of exposure to similar viruses that’s safeguarding them. There’s a phenomenon known as ADE, antibody-dependent enhancement, a phenomenon first described more than 50 years ago. In most cases, the antibodies our bodies make to target pathogens neutralize them or, at the very least, tag the invaders for removal. Sometimes, though, antibodies can actually facilitate viral infection and exacerbate disease.
This may be the case with SARS, where antibodies generated against the viral spike proteins were sometimes found to promote infection. In monkeys, an experimental SARS vaccine resulted in aggravated lung damage. Now, vaccine developers are well aware of this phenomenon, and would work to ensure any commercial vaccine would be free from this failing, but it has been used to venture a guess to account for the unusual age distribution of severe COVID-19 cases.
Perhaps similar coronaviruses circulated silently decades ago, and those old enough to have been exposed to them are now experiencing exaggerated responses to COVID-19. But young people never saw them, so they don’t get the over-reaction. I’m not suggesting this speculation is true. I just use it to illustrate the complexity of our immune interactions. Viruses attack, we counterattack, and then viruses sometimes evolve to use our own counterattack in their favor.
Just a word of caution before trying to specifically boost some element of our immune system before understanding the full scope of the new threat. Given the uncertainties, the best strategy is to not get infected in the first place, especially not until effective treatments— and a functioning healthcare system—are available.
Please consider volunteering to help out on the site.
- Leng Z, Yin D, Zhao Z, et al. A survey of 434 clinical trials about coronavirus disease 2019 in China. J Med Virol. 2020.
- Anderson RM, Heesterbeek H, Klinkenberg D, Hollingsworth TD. How will country-based mitigation measures influence the course of the COVID-19 epidemic?. Lancet. 2020;395(10228):931-4.
- Pronker ES, Weenen TC, Commandeur H, Claassen EH, Osterhaus AD. Risk in vaccine research and development quantified. PLoS ONE. 2013;8(3):e57755.
- Greger M. How Not to Die. 2015. Flatiron Books.
- Noah TL, Zhang H, Zhou H, et al. Effect of broccoli sprouts on nasal response to live attenuated influenza virus in smokers: a randomized, double-blind study. PLoS ONE. 2014;9(6):e98671.
- Müller L, Meyer M, Bauer RN, et al. Effect of Broccoli Sprouts and Live Attenuated Influenza Virus on Peripheral Blood Natural Killer Cells: A Randomized, Double-Blind Study. PLoS ONE. 2016;11(1):e0147742.
- Lifestyle Choices to Boost Immunity. American College of Lifestyle Medicine.
- Healthy diet. World Health Organization. April 29, 2020.
- Calder PC, Carr AC, Gombart AF, Eggersdorfer M. Optimal Nutritional Status for a Well-Functioning Immune System Is an Important Factor to Protect against Viral Infections. Nutrients. 2020;12(4).
- Spezzani V, Piunno A, Iselin HU. Benign COVID-19 in an immunocompromised cancer patient - the case of a married couple. Swiss Med Wkly. 2020;150:w20246.
- D'antiga L. Coronaviruses and immunosuppressed patients. The facts during the third epidemic. Liver Transpl. 2020.
- Pedersen SF, Ho YC. SARS-CoV-2: A Storm is Raging. J Clin Invest. 2020;130(5):2202-5.
- Siddiqi HK, Mehra MR. COVID-19 illness in native and immunosuppressed states: A clinical-therapeutic staging proposal. J Heart Lung Transplant. 2020;39(5):405-7.
- Upton JW, Chan FK. Staying alive: cell death in antiviral immunity. Mol Cell. 2014;54(2):273-80.
- Fung SY, Yuen KS, Ye ZW, Chan CP, Jin DY. A tug-of-war between severe acute respiratory syndrome coronavirus 2 and host antiviral defence: lessons from other pathogenic viruses. Emerg Microbes Infect. 2020;9(1):558-70.
- Mehta P, Mcauley DF, Brown M, et al. COVID-19: consider cytokine storm syndromes and immunosuppression. Lancet. 2020;395(10229):1033-4.
- Ritchie AI, Singanayagam A. Immunosuppression for hyperinflammation in COVID-19: a double-edged sword?. Lancet. 2020;395(10230):1111.
- Coates BM, Staricha KL, Wiese KM, Ridge KM. Influenza A Virus Infection, Innate Immunity, and Childhood. JAMA Pediatr. 2015;169(10):956-63.
- Zimmermann P, Curtis N. Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children. Pediatr Infect Dis J. 2020;39(5):355-68.
- Nickbakhsh S, Ho A, Marques DFP, Mcmenamin J, Gunson RN, Murcia PR. Epidemiology of seasonal coronaviruses: Establishing the context for COVID-19 emergence. J Infect Dis. 2020.
- Mizumoto K, Omori R, Nishiura H. Age specificity of cases and attack rate of novel coronavirus disease (COVID-19). medRxiv.org. March 13, 2020.
- Hawkes RA. Enhancement of the infectivity of arboviruses by specific antisera produced in domestic fowls. Aust J Exp Biol Med Sci. 1964;42:465-82.
- Tirado SM, Yoon KJ. Antibody-dependent enhancement of virus infection and disease. Viral Immunol. 2003;16(1):69-86.
- Wang SF, Tseng SP, Yen CH, et al. Antibody-dependent SARS coronavirus infection is mediated by antibodies against spike proteins. Biochem Biophys Res Commun. 2014;451(2):208-14.
- Liu L, Wei Q, Lin Q, et al. Anti-spike IgG causes severe acute lung injury by skewing macrophage responses during acute SARS-CoV infection. JCI Insight. 2019;4(4):e123158.
- Negro F. Is antibody-dependent enhancement playing a role in COVID-19 pathogenesis?. Swiss Med Wkly. 2020;150:w20249.
- Coronavirus Disease 2019 (COVID-19). Centers for Disease Control and Prevention.
Motion graphics by AvoMedia
Image credit: hochgeladen von via Wikimedia. Image has been modified.
- American College of Lifestyle Medicine
- animal products
- Asia
- beans
- broccoli sprouts
- chickpeas
- children
- China
- common cold
- coronavirus
- COVID-19
- exercise
- fruit
- grains
- immune function
- inflammation
- junk food
- legumes
- lentils
- lifestyle medicine
- lung health
- meat
- nuts
- pandemics
- processed foods
- respiratory infections
- sleep
- split peas
- sugar
- vaccines
- vegetables
- viral infections
- zoonotic disease
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Though there are more than 400 clinical treatment trials underway, currently there is no specific proven therapy for COVID-19. And we should not expect a vaccine or effective antiviral drug to be available anytime soon, although we are developing COVID-19 vaccines at pandemic speed. Just for reference, the average vaccine takes more than a decade to develop, with an average failure rate of 94%.
Many have asked me for advice on what they can eat to help bolster their immune system. “How Not to Die from Infections” is, after all, the title of chapter five of my book How Not to Die, and I do have more than a hundred free videos online at NutritionFacts.org that reference immune function. And there are amazing studies, like randomized double-blind trials, showing, for example, that eating broccoli sprouts can reduce viral loads for influenza, decrease virus-induced inflammation, and boost our antiviral natural killer cell activity. Just from eating some broccoli sprouts! But this isn’t the flu.
I certainly support general, commonsense advice to stay healthy during the crisis, put forth by trusted authorities such as the American College of Lifestyle Medicine. This includes getting sufficient sleep (seven to nine hours), keeping active, reducing stress, staying connected—albeit remotely—to friends and family, and eating healthfully (a diet centered around whole plant foods)., The World Health Organization agrees: Fruits, vegetables, legumes—like beans, split peas, chickpeas, and lentils—nuts, and whole grains, cutting down on sugars, cutting down on meat, dairy, and junk, and cutting down on salt.
“Optimal Nutritional Status for a Well-Functioning Immune System Is an Important Factor to Protect against Viral Infections.” However, one must resist the urge to jump on the snake-oily spamwagon of foods to boost your immune system, given our near-total ignorance of the immunological aspects of this new disease, because enhancing specific arms of the immune system could hypothetically even make things worse. Let me explain.
Take the example of this married couple, both the same age, admitted to the hospital on the same day for the same COVID-19 infection—fever and shortness of breath. Tragically, the wife was immunocompromised, because she was on chemo for breast cancer at the time (yikes!), whereas her husband had an intact immune system. The wife did fine, though, out of the hospital in under a week, whereas the husband ended up in intensive care. Wait, the immunocompromised patient did better? How is that possible? Because unlike other common viruses, coronaviruses have not shown to cause a more severe disease in immunosuppressed patients. Why? Because your own immune response appears to be the main driver of lung tissue damage during infection.
Starting around the second week of symptoms, the virus can trigger what’s called a cytokine storm. It’s like an autoimmune reaction where your body over-reacts, and in attacking coronavirus, your lungs get caught in the crossfire. In the first week of the illness, it’s the virus itself that’s triggering most of your symptoms, but then in severe cases, it’s our own inflammatory response that takes over in causing most of the damage. It’s striking that many of our innate immune-signaling pathways, these cytokine chemical messengers our immune cells release, is aimed at killing off our own cells. But that makes total sense. The virus turns our own cells against us into little virus factories, so it’s part of our own antiviral defense to kill off our own cells to dead-end viral replication. Viruses can’t replicate in dead cells, so cell suicide is like a way to create firebreaks. But in burning down the village in order to save it, we may not survive the process.
This has led some to consider immunosuppression as a treatment for severe COVID-19, but of course immunosuppression for hyperinflammation in COVID-19 might be a double-edged sword. So, when you see that broccoli sprouts can whip up natural killer cell activity within two days, is that a good thing or a bad thing for COVID-19? It was good for seasonal flu, but who knows with this new coronavirus.
Young children have relatively immature immune systems, and normally suffer disproportionally from viral infections such as the flu––but not, apparently, from COVD-19 or SARS or MERS, for that matter, the other two deadly coronaviruses. It’s interesting; one theory as to why children seem protected suggests that greater pre-existing exposure to common-cold coronaviruses offers kids some cross-protection against the new virus. But ironically, a competing theory suggests it’s their lack of exposure to similar viruses that’s safeguarding them. There’s a phenomenon known as ADE, antibody-dependent enhancement, a phenomenon first described more than 50 years ago. In most cases, the antibodies our bodies make to target pathogens neutralize them or, at the very least, tag the invaders for removal. Sometimes, though, antibodies can actually facilitate viral infection and exacerbate disease.
This may be the case with SARS, where antibodies generated against the viral spike proteins were sometimes found to promote infection. In monkeys, an experimental SARS vaccine resulted in aggravated lung damage. Now, vaccine developers are well aware of this phenomenon, and would work to ensure any commercial vaccine would be free from this failing, but it has been used to venture a guess to account for the unusual age distribution of severe COVID-19 cases.
Perhaps similar coronaviruses circulated silently decades ago, and those old enough to have been exposed to them are now experiencing exaggerated responses to COVID-19. But young people never saw them, so they don’t get the over-reaction. I’m not suggesting this speculation is true. I just use it to illustrate the complexity of our immune interactions. Viruses attack, we counterattack, and then viruses sometimes evolve to use our own counterattack in their favor.
Just a word of caution before trying to specifically boost some element of our immune system before understanding the full scope of the new threat. Given the uncertainties, the best strategy is to not get infected in the first place, especially not until effective treatments— and a functioning healthcare system—are available.
Please consider volunteering to help out on the site.
- Leng Z, Yin D, Zhao Z, et al. A survey of 434 clinical trials about coronavirus disease 2019 in China. J Med Virol. 2020.
- Anderson RM, Heesterbeek H, Klinkenberg D, Hollingsworth TD. How will country-based mitigation measures influence the course of the COVID-19 epidemic?. Lancet. 2020;395(10228):931-4.
- Pronker ES, Weenen TC, Commandeur H, Claassen EH, Osterhaus AD. Risk in vaccine research and development quantified. PLoS ONE. 2013;8(3):e57755.
- Greger M. How Not to Die. 2015. Flatiron Books.
- Noah TL, Zhang H, Zhou H, et al. Effect of broccoli sprouts on nasal response to live attenuated influenza virus in smokers: a randomized, double-blind study. PLoS ONE. 2014;9(6):e98671.
- Müller L, Meyer M, Bauer RN, et al. Effect of Broccoli Sprouts and Live Attenuated Influenza Virus on Peripheral Blood Natural Killer Cells: A Randomized, Double-Blind Study. PLoS ONE. 2016;11(1):e0147742.
- Lifestyle Choices to Boost Immunity. American College of Lifestyle Medicine.
- Healthy diet. World Health Organization. April 29, 2020.
- Calder PC, Carr AC, Gombart AF, Eggersdorfer M. Optimal Nutritional Status for a Well-Functioning Immune System Is an Important Factor to Protect against Viral Infections. Nutrients. 2020;12(4).
- Spezzani V, Piunno A, Iselin HU. Benign COVID-19 in an immunocompromised cancer patient - the case of a married couple. Swiss Med Wkly. 2020;150:w20246.
- D'antiga L. Coronaviruses and immunosuppressed patients. The facts during the third epidemic. Liver Transpl. 2020.
- Pedersen SF, Ho YC. SARS-CoV-2: A Storm is Raging. J Clin Invest. 2020;130(5):2202-5.
- Siddiqi HK, Mehra MR. COVID-19 illness in native and immunosuppressed states: A clinical-therapeutic staging proposal. J Heart Lung Transplant. 2020;39(5):405-7.
- Upton JW, Chan FK. Staying alive: cell death in antiviral immunity. Mol Cell. 2014;54(2):273-80.
- Fung SY, Yuen KS, Ye ZW, Chan CP, Jin DY. A tug-of-war between severe acute respiratory syndrome coronavirus 2 and host antiviral defence: lessons from other pathogenic viruses. Emerg Microbes Infect. 2020;9(1):558-70.
- Mehta P, Mcauley DF, Brown M, et al. COVID-19: consider cytokine storm syndromes and immunosuppression. Lancet. 2020;395(10229):1033-4.
- Ritchie AI, Singanayagam A. Immunosuppression for hyperinflammation in COVID-19: a double-edged sword?. Lancet. 2020;395(10230):1111.
- Coates BM, Staricha KL, Wiese KM, Ridge KM. Influenza A Virus Infection, Innate Immunity, and Childhood. JAMA Pediatr. 2015;169(10):956-63.
- Zimmermann P, Curtis N. Coronavirus Infections in Children Including COVID-19: An Overview of the Epidemiology, Clinical Features, Diagnosis, Treatment and Prevention Options in Children. Pediatr Infect Dis J. 2020;39(5):355-68.
- Nickbakhsh S, Ho A, Marques DFP, Mcmenamin J, Gunson RN, Murcia PR. Epidemiology of seasonal coronaviruses: Establishing the context for COVID-19 emergence. J Infect Dis. 2020.
- Mizumoto K, Omori R, Nishiura H. Age specificity of cases and attack rate of novel coronavirus disease (COVID-19). medRxiv.org. March 13, 2020.
- Hawkes RA. Enhancement of the infectivity of arboviruses by specific antisera produced in domestic fowls. Aust J Exp Biol Med Sci. 1964;42:465-82.
- Tirado SM, Yoon KJ. Antibody-dependent enhancement of virus infection and disease. Viral Immunol. 2003;16(1):69-86.
- Wang SF, Tseng SP, Yen CH, et al. Antibody-dependent SARS coronavirus infection is mediated by antibodies against spike proteins. Biochem Biophys Res Commun. 2014;451(2):208-14.
- Liu L, Wei Q, Lin Q, et al. Anti-spike IgG causes severe acute lung injury by skewing macrophage responses during acute SARS-CoV infection. JCI Insight. 2019;4(4):e123158.
- Negro F. Is antibody-dependent enhancement playing a role in COVID-19 pathogenesis?. Swiss Med Wkly. 2020;150:w20249.
- Coronavirus Disease 2019 (COVID-19). Centers for Disease Control and Prevention.
Motion graphics by AvoMedia
Image credit: hochgeladen von via Wikimedia. Image has been modified.
- American College of Lifestyle Medicine
- animal products
- Asia
- beans
- broccoli sprouts
- chickpeas
- children
- China
- common cold
- coronavirus
- COVID-19
- exercise
- fruit
- grains
- immune function
- inflammation
- junk food
- legumes
- lentils
- lifestyle medicine
- lung health
- meat
- nuts
- pandemics
- processed foods
- respiratory infections
- sleep
- split peas
- sugar
- vaccines
- vegetables
- viral infections
- zoonotic disease
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The Immune System and COVID-19 Treatment
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Content URLDoctor's Note
We’re halfway through this 17-video series on COVID-19. If you’ve missed any, start with:
- Where Do Deadly Coronaviruses Like MERS-CoV Come From?
- The SARS Coronavirus and Wet Markets
- Where Did the COVID-19 Coronavirus Come From?
- The Last Coronavirus Pandemic May Have Been Caused by Livestock
- R0 and Incubation Periods: How Other Coronavirus Outbreaks Were Stopped
- Social Distancing, Lockdowns & Testing: How to Slow the COVID-19 Pandemic
- COVID-19 Symptoms vs. the Flu, a Cold or Allergies
- Modifiable Risk Factors and Comorbidities for Severe COVID-19 Infection
Still to come:
- Would Zinc Lozenges Help with COVID-19?
- How to Avoid COVID-19
- Hand Washing & Sanitizing to Inactivate COVID-19 Coronavirus
- What to Do if You Come Down with COVID-19
- The Best Mask or DIY Face Covering for COVID-19
- How COVID-19 Ends: Vaccination, Mutations, and Herd Immunity
- The COVID-19 Pandemic May Just Be a Dress Rehearsal
- How to Prevent the Next Pandemic
You can download the whole series (for free) here, and take an even deeper dive in my new book How to Survive a Pandemic (note: all my proceeds from this book are donated to pandemic prevention charities).
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