Can anything really “boost” your immune system? And how does it fight off infections? Rheumatologist and immune system expert Leonard Calabrese, DO, explains how the amazing immune system works and what we can do to keep it as strong as possible.

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How to Optimize Your Immune Health with Dr. Leonard Calabrese

Podcast Transcript

Deanna Pogorelc:  Hello and welcome to the Health Essentials podcast brought to you by Cleveland Clinic. I'm your host Deanna Pogorelc. Today we're talking about the immune system. It's your body's first and best line of defense against internal threats like inflammation as well as external threats like viral and bacterial infections. In the face of the COVID-19 pandemic, you might be wondering whether there's anything you can do to strengthen your body's immune system. Joining us today to help us get to the bottom of that is Dr. Leonard Calabrese. Dr. Calabrese is a rheumatologist who heads Cleveland Clinic's section of clinical immunology and specializes in diseases of the immune system. Hi, Dr. Calabrese, thanks for being here.

Dr. Leonard Calabrese:  Hey, thanks for having me.

Deanna Pogorelc:  Just a note to our listeners that we are recording virtually today to follow safe social distancing guidelines. And also please remember that this is for informational purposes only and is not intended to replace your own physician's advice. Dr. Calabrese, can we start with just a little bit of a primer about the immune system? What is it? What are the different components of it? And how does it work to protect us?

Dr. Leonard Calabrese:  Yeah, I can't think of a better point in time than now to talk about the immune system and immune health as we're in the middle of this pandemic, or at least getting to the middle I hope. There's just so much out there talking about our immune system, our resistance, how we respond to this, what it contributes to in terms of this disease. And that as an immunologist who's been doing this for decades, I'm really impressed by how much bad information is out there. Offering people quit fixes and easy ways out. But the immune system is really a remarkable organ. I look at fitness, I look at wellness as being multidimensional. We want to train to get fit, we go run, we increase our aerobic capacity, we lift weights to become strong. We do brain games to make our mind strong.

Dr. Leonard Calabrese:  But the real question is, what do we do for our immune system? And why should we be concerned about it? Our immune system, are all those defenses that reside within us, that defend us against danger. That's the easiest way to think about it. It's not just infections because we're covered with infections and infested with infections and we get along with most of our infectious brethren quite nicely. But from time to time, infections become dangerous, ranging from the common cold to COVID-19.

Dr. Leonard Calabrese:  Our immune system also protects us from other sorts of danger, from allergic responses and toxins and harmful effects of our own bodies kind of take out the garbage machinery that has to get rid of all of our dead cells. The immune system is just tightly woven into our physiology. And I like to think that when we're well, and you might want to say, "Well, what does wellness mean?" And I think, we all recognize wellness. When our lives are going good, we're well. It's not just being free from disease, it's being robust in mind, body and spirit. When we're well, our immune system is really humming along and working at a very high rate of efficiency to protect us from all these dangerous signals.

Dr. Leonard Calabrese:  We think about it as occurring in two basic compartments, one we call innate, another we call adaptive. The easy way to remember this is that innate is our early warning system. You prick your finger on a rusty nail on a Sunday stroll through the park when you're touching the fence. If that rusty nail has a dangerous bacteria, we have defenses located in an under our skin and other areas that set off alarms to tell us there is danger here in this finger. We need to dispatch it. All of these cells and proteins and mediators come to the fore. We either heal it up and a few days later our finger is fine, or a few days later our finger is festering and we need help.

Dr. Leonard Calabrese:  And that calls in the adaptive immune response. Those are kind of the heavy weaponry of our immune system. And we think of those as T cells and B cells and things that we've kind of heard of. But these are our cells that are very specialized and can respond with great precision and accuracy. Together innate and adaptive immunity are a powerful force. They identify when a stimulus is dangerous or not. They tell the immune system what is the danger. They tell the immune system how to dispatch it. And lastly, they tell the immune system where to go find it. It's a remarkable system and we need it desperately now more than ever.

Deanna Pogorelc:  What kind of factors go into how strong our immune system is or isn't in that reaction?

Dr. Leonard Calabrese:  Well, it's kind of an interesting phenomena. Most of us, our immune system works pretty good and, but before a century ago, a lot of people died very young because of bacterial infections, before the introduction of antibiotics. Today we recognize that our immune systems do a pretty good job. But there are some caveats. First of all, our immune systems work better when we're young. Not tiny babies, but after we get to be around adolescents, our immune system is really at our peak probably until we're about 18 or 19. I'm sorry to tell everybody that, but after that, the biologic imperative is reproduce and go away. But we all want to live to be long and we want to live to be healthy.

Dr. Leonard Calabrese:  Over time, our immune system works well, but the most common form of deficiency of immunity is the immunodeficiency of aging. And it is inevitable that over time our immune system runs down. And I don't think that anyone has to be convinced of this just to watch the news and see that probably the greatest single variable in COVID-19 epidemic is age along with other, what we call comorbidities, diseases that also the immune system is contributing to. Age related immunodeficiency is very common.

Dr. Leonard Calabrese:  There are other factors. Of course, diseases like HIV AIDS where our immune system is attacked by the HIV virus. Some rare diseases are children that are born with deficient immune systems and others who adults develop immunodeficiencies in early life.

Dr. Leonard Calabrese:  And then lastly, there are diseases of the immune system from secondary causes. We develop cancer or we have an autoimmune disease and we have to take immunosuppressive drugs. All of these tend to suppress our immune system.

Dr. Leonard Calabrese:  And then lastly, people who are in poor physiologic condition, people who weigh more than they should. People who have diabetes, cardiovascular disease, metabolic syndrome with hypertension, fatty liver and beyond. All of these individuals have dysregulated immune systems. There are a lot of different ways to suppress our immunity. Some are genetic, some are acquired, some occur with age.

Deanna Pogorelc:  Are any of us immune to the coronavirus? either without having it or after having it?

Dr. Leonard Calabrese:  That's a really great question. I wouldn't say immune. We say immune in my business, that means that we have seen a danger signal and we have memory of it and we defend ourselves against this. Well since this is a new infection, none of us have immunologic memory for a COVID-19 but if we look through these remarkable epidemiologic studies going on, know why in a group of people do nine out of 10 get it and one does not? Is that because that person had less of a viral exposure? Or does that mean there's something special about their immune system that protects them? We don't know yet, but that's a very important point. And some of us are just more resistant to infections than others. Just look at your own family. Who's the person always gets the cold? Who's the person that doesn't always get the cold? Work in progress.

Deanna Pogorelc:  Yeah. And one thing we've heard about COVID-19 like you mentioned, is that people who have the compromised immune system tend to be more at risk for a higher infection. And is that the only thing that contributes to how people are experiencing this virus? And also what kind of things can cause the immune system to be compromised?

Dr. Leonard Calabrese:  Well, there's a lot of reasons for immune compromised. The easiest one is when people are taking immunosuppressive drugs, when they're taking steroids as we say. These often used to treat all types of allergic and autoimmune diseases. People are taking immunosuppressive drugs for serious immune mediated diseases. Patients with cancer who are getting chemotherapy and radiation. This all compromises immunity. That's an easy group.

Dr. Leonard Calabrese:  Second group are people that just have these immune diseases. They're not, we don't think of them as being totally immunosuppressed, but their immune system is different than healthy people. And we actually don't know what risk that imparts in terms of COVID-19. It might be mild or a moderate or severe and maybe far less. We're just learning that right now.

Dr. Leonard Calabrese:  And then lastly, there are a variety of genetic factors that would contribute to that. But the greatest risk factor to the immune system that I know of that is predictable is age. And people less than 50 tend to do quite well. People less than 40 do really well and there are sad and devastating exceptions to all of this, but as we get greater than 50, 60, 70, 80, we think that the changes of the immune system, changes in our immune health, are major contributors to the accelerated disease burden of COVID-19.

Deanna Pogorelc:  We've heard a lot of talk in the news about the potential for a vaccine in the future. Can you talk a little bit about how vaccines work, how they're developed and what they do inside our bodies?

Dr. Leonard Calabrese:  Vaccines are the greatest single boon to public health that have ever been invented past knowing how to drink clean water. They're just the most vital part of our defenses against pandemics. And we've eliminated so many terrible scourges of infections over the years. The goal here is to develop an effective vaccine that is safe, that can protect the planet. Our immune system, as I told you, once it is experienced with a dangerous signal, it can retain memory of it for life. And some vaccines work very well. We get our childhood vaccines for many pathogens and they work for our whole lives and others are not so well like the flu. We need to boost it every year. There's over a 100 candidate vaccines. I hope to see one within the year. Keep our fingers crossed. It could be faster, but this will be the way moving forward to get to our new normal.

Deanna Pogorelc:  But something like the flu or the pneumonia vaccine would not protect against coronavirus. Why is that?

Dr. Leonard Calabrese:  No. Well, because our memory is very specific for the danger signals. One vaccine for one problem. But being vaccinated now is even more important because people who get two or more infections with COVID do much, much worse. And so we need to stay up on our vaccine status.

Deanna Pogorelc:  We talk about vaccines, I've heard the word antibody used a lot. Can you explain what that is?

Dr. Leonard Calabrese:  Antibodies are part of our adaptive immune system. We have these T cells that go in and rip the infections out where they reside. And we have antibodies, these proteins in our blood that are spewed out of cells called B cells that circulate and neutralize danger signals before they've had a chance to infect our tissue. There's a lot of work going on now that people have recovered from COVID-19, harvesting their antibodies and giving them to people who are acutely ill. We'll have to see if that works out, but it's an interesting concept.

Deanna Pogorelc:  I also hear the phrase herd immunity a lot. Can you explain a little bit about what that means and why it's important?

Dr. Leonard Calabrese:  Herd immunity is a very important concept. If you have one person in the community infected, they could infect literally the entire community if everyone was in contact and spreading this around. If on the other hand, many people in the community have already been infected and have memory and those are the only people that come into contact with this infected person, that immunity of the herd would block it from spreading to the most vulnerable people. It takes a lot of people to develop effective herd immunity, but even a little bit goes a long way.

Deanna Pogorelc:  I want to get into some of the things that we can do to keep our immune system working the best that it possibly can. We see a lot of products that are advertised like vitamins or essential oils claiming to boost the immune system. Is it actually possible that these things could be strengthening our immune system?

Dr. Leonard Calabrese:  First, let me tell you, there is no bigger advocate on the planet for developing immune strength as I like to call it, than myself. And I believe that our behaviors affect our immune system and as we modify our behaviors we can grow and maintain a healthy immune system.

Dr. Leonard Calabrese:  The second thing I will say is that there is virtually nothing that you can go out and buy to do this. And if it is something that is easy and it is put forth as a quick fix, my antennas go up and it probably is far less effective than what is being advertised. Having said that, I'll put that off to the end about supplements and quick fixes and tell you the big four things that lead to immune health.

Dr. Leonard Calabrese:  The first and most important thing is dietary. And the diet that is best for your immune system is eating real food, mostly plants and not being obese. Or if you are overweight, working on that. A Mediterranean like diet or a paleo diet or a hybrid as my friend Mark Hyman says, the pegan diet, all can be very good, but real food is the key to this. Avoiding stripped carbohydrates, raw sugars, processed food, and what we call the standard American diet is a great blow to our immune system and generates inflammation, which in a chronic phase is unhealthy. A healthy diet that is largely plant based, with good food products is key.

Dr. Leonard Calabrese:

Secondly is physical activity. And we're generating a lot of very useful information and data to show that being sedentary is dangerous to our immune system and that exercising moderate to vigorously can protect us from common respiratory pathogens. Can it protect us from COVID-19? I'm not here to guarantee that one way or the other, but it has clearly been demonstrated by studies of people from inactive to active that we can control our immune system. Some very recent data which has been calling into question, people used to caution against very vigorous exercise saying that that could actually suppress our immune system, but some very vigorous exercise studies coming out right now suggest that not only might it be good for our immune system, but it might actually help calm inflammation.

Dr. Leonard Calabrese:  The third pillar of immunologic health is getting adequate and restful sleep. And at this point in time in the COVID-19 epidemic, that may be harder than ever. Our minds race, we're stressed out. We're worried about all types of security in our lives. But getting more than six and a half, I favor greater than seven hours an evening of sleep is very important to our immune system. When we get less than that, that drives up inflammation and tends to grind our immune, this wonderful immune machine to a halt. Sleep is hard to correct. And so there's a lot of online programs. We have a wonderful program at the Cleveland Clinic called Go to Sleep, which is a cognitive behavioral approach to getting your sleep back.

Dr. Leonard Calabrese:  The last thing is the hardest and the most important. And I would say that the greatest threat to immunologic health over our lifetime is psychosocial stress. We now have molecular evidence that when we are happy and that doesn't mean joy, we won the game. When we are internally happy with our lives. This you dynamic state of being satisfied. Inflammation goes down and immune health goes up. When we're socially isolated, when we have stresses that may be beyond our control, when we are depressed or anxious, when we don't handle our stresses the way that we really want to, all of that is immunocompromising and now there's a tremendous amount of data to show that there are mind body techniques ranging from what I call the bottom up. Using our bodies like yoga and Tai Chi. Top down things like mindfulness meditation that can calm the flame of inflammation and bring us health.

Dr. Leonard Calabrese:  Now on top of all of those things, the last thing I'll say is that it goes without saying, you got to get rid of the bad things. You can't live this type of life, smoking a cigarette or drinking accesses of alcohol or taking drugs or exposing yourself to toxins. Get rid of the negatives, healthy diet, healthy exercise, healthy sleep, healthy mind, and that leads to immune health. And you can generate this over a matter of weeks. You can start to optimize it. We know this for a fact and I want everybody to get on the bus.

Deanna Pogorelc:  Yeah, so you kind of hinted at it, but I want to just reiterate. We do have some control to optimize or strengthen our immune system. It's not necessarily set in one way for our entire lives?

Dr. Leonard Calabrese:  That's exactly right. And in fact, we all age at a different rate. Immunologically speaking, we age at a different rate. Otherwise you look at somebody and you say, "Oh, that guy is 75, he looks 55. This person looks 75 and they're only 55." Our immune systems do the same thing. And we're starting to understand that lifestyle modifications have a lot to do with it. Heavy tobacco use, the onset of depression, poor sleep, a sedentary lifestyle, all very important.

Dr. Leonard Calabrese:  The last thing I want to bring up is that, I'm not here to make fun of the quick fix, quick fixes offered for immune health. And there's a lot of good things to be said about data for anti-inflammatory supplements such as curcumin, quercetin and a variety, vitamin D and a variety of other factors. In the monograph that I give to every one of my immune disease patients, I tell them that taking a balanced multivitamin and make sure they're not vitamin D deficient is absolutely important as part of this. But the quick fix that you think you can take vitamin C and all of a sudden eliminate the need to do all of these behaviors is not accurate. And we could look for more evidence of how effective these things are to generate immune health, but they pale in terms of a lifetime and a chronic application, healthy eating, healthy exercise, healthy sleep and relieving psychosocial stress.

Deanna Pogorelc:  How could we measure our immune health?

Dr. Leonard Calabrese:  Well there's two large ways that we think about this. One is, a research based way of measuring our immune health and we don't have access to that, but we can measure our innate and adaptive immune responses. And that's how many of these studies that look how our immune system goes over our age are actually done. A more transparent view of immune health is that, how many and how severe are the infections that you get during a calendar year? If you live a place like northern Ohio and the north coast here, everybody has a few colds a year, it's not, that doesn't mean you're immunodeficient. But is three too many? Is one enough? These are ways. If you have a serious infection or you develop an immunologic disease, that means that there's some more fundamental problem with your immune system. But there's a lot of validity to just thinking about this clearly.

Deanna Pogorelc:  And the last question I want to ask you is what kind of exciting research is happening in the area of immunology? What are you looking forward to learning? Or what can we expect to learn more about in the future?

Dr. Leonard Calabrese:  Everything. We're particularly interested in proving that the behaviors that I have suggested to you are actually effective. And we have a program that is just coming to fruition called Immune Strength, which is a 10 week online e-coached behavioral modification program that teaches healthy eating, exercise, sleep and stress. And we're looking to see in a research setting, can it enhance our innate and adaptive immune responses and improve quality of life? And improve our sleep and increase our energy and decrease our fatigue? Can it lower our pain levels? All of these are experimental questions.

Dr. Leonard Calabrese:  I believe that this is true, but there's a famous saying that says, "Trust, but verify." And we're doing work in this space to do this. We're starting with [inaudible 00:26:08] immunologic diseases to test this on them and we're now starting to look at people who are worried about their own immunologic health in the COVID-19 era. More this summer about how that project will be going. Other than that, we're now also working in COVID-19 space, taking the drugs that are used to treat immune mediated diseases and actually turning them on COVID-19 because this is an infection that co-ops our immune system to do terrible amounts of damage as well.

Deanna Pogorelc:  Well, thank you so much Dr. Calabrese for this really important information. We really appreciate it. And for the latest on COVID-19, you can visit To listen to more of our Health Essentials podcasts with our Cleveland Clinic experts, visit or subscribe wherever you get your podcasts. And for more health tips, news, and information, you can follow us @ClevelandClinic, one word on Facebook, Twitter, and Instagram. Thanks for joining us.

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