Tolerating Disease Versus Fighting It

What causes animals (or humans) with identical genetic codes, gut microbes, and germ exposure to survive the same pathogen (and pathogen dosage), while another dies? Could the answer lie in manipulating the body to tolerate disease as opposed to fighting it? This is a theme that has received lots of attention in the last five years, and one worth discussing, especially in the midst of the pandemic.

An article published in The Scientist in June 2019 highlighted a series of rodent studies that investigated this phenomenon. One study in particular showed that providing nutrients for the host when pathogens invade the body could help in maximizing host health and survival. Researchers infected a group of mice (all were identical in terms of genetic code, microbial makeup, diet, and environment) with a pathogenic bacterium, Citrobacter rodentium. Exposure was kept constant across all mice, and pathogenic bacteria levels were identical in the gut and other tissues. Interestingly, within a few days some mice developed severe inflammation and died shortly after, while other mice remained healthy with no signs of disease.

We can all relate to this experiment. Why do some of us get sick, while others don’t, despite being exposed to the same “germs” and coming from the same environment? As scientists investigated the genetic differences between the sick and healthy mice in response to the pathogen, they found that the mice that showed no signs of disease also showed high levels of genes associated with metabolizing iron. In follow-up experiments, iron supplementation helped save the rodents who fell ill. Following the study, scientists proposed that instead of trying to wipe out pathogens from the body, perhaps we should be trying to figure out a way to manipulate the host in order to create disease tolerance –transforming the body’s physiology in order to create a stronger host more resistant to pathogens.

Up until now, especially in the case of bacterial infections, our main line of defense has been complete eradication. But this research suggests there may be a better way. Some medications already work to improve tolerance, but what about taking this concept a step further into the realm of our everyday lives? Implementing lifestyle changes that not only dampen the virulence of pathogens, but also transform the physiology and increase the strength of the body? This doesn’t mean just popping a supplement (which you may have been thinking when reading the above study regarding iron supplementation). While taking supplements may offer us peace of mind, an in-depth look at the scientific literature shows us that supplements offer very little in terms of boosting health.

The idea of altering physiology to tolerate exposure, as opposed to fighting a pathogen head on with modern medicine once the body has already been infected is an interesting concept, particularly as we continue to find ways to prevent and treat COVID-19. While we don’t have a pill that proves successful in preventing or treating the disease, we do know something about who falls severely ill from the virus and who doesn’t, as well as ways to strengthen the body in order to tolerate viral infection. Some important things we’ve uncovered in the research during the pandemic include:

• There’s a strong relationship between the gut microbiome and severe/fatal COVID-19. Specific bacteria strains and microbial characteristics are associated with an increased risk in COVID that requires hospitalization. What can we take away from these findings? Protecting your gut microbiome to promote rich bacterial diversity and balanced microbial ratios is important when looking to lower your risk of this severe form of the disease. There is no better way to do this than to consume a diet rich in whole plant foods, eliminating medications that are harmful to the microbiome, and living “dirty”. For a step-by-step guide on how to do this, including a shopping list and recipes, check out Dr. Chutkan’s book, The Microbiome Solution: A radical new way to heal the body from the inside out.

• Lifestyle factors can help protect the immune system from contracting viral infections like coronavirus, including:
  • adequate sleep
  • stress reduction
  • a healthful diet
  • exercise
  • exposure to fresh air and sunlight

While no specific studies have directly linked these lifestyle modifications to preventing or treating COVID, we know through strong scientific evidence that practicing these lifestyle behaviors results in a stronger immune system that protects the body from pathogens and can actually significantly lower the risk of contracting viral infections. In addition, making the above-mentioned behaviors habitual protects against the co-morbidities (see below) that are associated with as much as 95% of severe COVID cases.

• Comorbidities are a strong determining factor in who gets sick with severe COVID-19. Those conditions with the greatest associated risk include chronic kidney disease, COPD (chronic obstructive pulmonary disease), those with a weakened immune system from organ transplant, obesity (a BMI greater than or equal to 30), serious cardiovascular conditions (heart failure, coronary artery disease, or cardiomyopathies), sickle cell disease, and type 2 diabetes (in fact, the relationship between COVID-19 and diabetes is bidirectional). There are many other conditions that preliminary research has suggested puts individuals at a higher risk for severe COVID, but the research is still non-conclusive.
• Adequate Vitamin D levels may play a role in protecting against the disease, but there is no definitive proof that vitamin D supplementation helps in treating or preventing COVID-19. Because of the key role vitamin D plays in immune health, we recommend a series of lifestyle practices in order to maintain adequate vitamin D levels. And if you are vitamin D deficient, a vitamin D supplement may help. See our comprehensive review on vitamin D in last month’s edition here.

• Cortisol levels (stress) may play a role in determining who gets severe COVID-19. While the study linking elevated cortisol levels to severe COVID was the first of its kind, a strong association seems to exist. Keeping your stress levels in check on a daily basis is a good idea always, but especially during a pandemic where stress mounts with the daily practice of social distancing and isolation.

Remember that while some people get seriously ill and it’s difficult to pinpoint exactly how or why, in the majority of cases, serious illness doesn’t just fall out of the sky. It is most times prefaced by a combination of poor diet, genetic risk, other chronic medical problems, immune suppressing medications – and of course, limited access to health care that disproportionately affects black and brown people in the US. This isn’t to say that all illness is preventable. It is to say that most illness is preventable, and when it’s not preventable, the stronger our bodies and immune systems are, the better able we are to tolerate harmful pathogens. And how do we make our bodies stronger – or in other words, better able to tolerate disease? In short, like the mice, feed it things that will allow your body to use its metabolic and immunologic capabilities to their highest powers – lots of veggies, sleep, exercise, and exposure to the great outdoors.