Try This: Modifiable Risk Factors for COVID

What is the strongest risk factor for COVID-19 to date? It’s having one or more comorbidities, specifically the ones related to poor metabolic health like obesity, diabetes, and heart disease.

That’s why, with Omicron dominating the news, I wanted to devote today’s newsletter to breakdown down just exactly what the top comorbidities are, exactly how they increase your risk of COVID-19, and what you or your loved ones can do today to radically reduce your risk exposure based on the latest science.

Before we jump in, I want to mention that today’s newsletter does not talk about vaccines. But as I shared last week, vaccines very much play a role when it comes to the COVID-19, especially for those in high-risk categories. But these days you can’t talk about COVID without re-stating clearly that you are not against vaccines. So just for the record, I’m not against vaccines. Contrary to what the news tells us, we can have layered and nuanced thoughts when it comes to the topic of vaccines, and last week I shared mine. But today’s newsletter isn’t about all that. Today’s newsletter is about a deep dive into comorbidities, so let’s jump in!

My friend Shawn Stevenson once said, “Chronic disease loaded the gun and Covid-19 pulled the trigger.”

We’ve known about this since early on, and it’s been documented in the research thousands of times since the initial outbreak. In one UK study, patients with one or two comorbidities had a 70% higher risk of death and those with three or more comorbidities had a 130% higher risk of death than those who had none (1).

According to the CDC, six out of every 10 US adults have one chronic disease, and four out of every 10 have two or more. Chronic disease alone is responsible for 41 million deaths, or 71 percent of global deaths annually—that’s roughly eight times the number of people who have died from COVID thus far.

And I don’t say that to underplay the destruction COVID-19 has caused, but I do want to offer some perspective on why we are having such a hard time getting through this thing. If chronic diseases are the leading cause of death and the number one risk factor for COVID-19, shouldn’t we also be addressing that

The good news is most chronic diseases are being driven by diet and lifestyle factors—the stuff that’s in our control! We have autonomy over what we choose to put into our bodies. How we treat and take care of ourselves is ultimately up to us.

That’s why I’m excited to share the most salient points from this review paper titled “Modifiable Risk Factors for SARS-CoV-2” (you can read it here) co-written by my friend and one of the founders of the Institute for Functional Medicine, Dr. Joseph Pizzorno.

We’ve covered many of these topics before in previous Try This newsletters, so I’ll be linking to those and further readings throughout the newsletter. My goal is to build your confidence that your modifiable health plays a pivotal role in your response to COVID-19. In my protocol today, I’m giving you practical tips for integrating the takeaways from Pizzorno’s paper into your everyday life.

Modifiable Risk Factors For SARS-CoV-2

Let’s dive right into the most researched-backed modifiable risk factors (aka the stuff that’s in our power to change) Pizzoro discusses in his review paper.

1. Blood Sugar. Pizzorno calls on a few studies that highlight why fasting blood glucose (FBG) is relevant to COVID-19. Having a FBG of 100-125 mg/dL (pre-diabetes range) or higher leading up to infection increases the risk of severe COVID-19 regardless of whether or not a person has a diabetes diagnosis (2).

According to the NIH, an estimated 88 million Americans have pre-diabetes, and of those, most don’t even know they have it. To make matters worse, if their FBG falls within the pre-diabetic range, there’s usually no action taken by healthcare providers to prevent it from getting worse (called the “watch and wait” approach—once FBG finally gets high enough to warrant a diabetes diagnosis, then action is taken)—no wonder we’re in this mess!

I’ve discussed blood sugar a bunch in previous newsletters (Try This: Manage Your Blood Glucose Levels, Try This: Breakfast Protocol) and in podcasts featuring insulin resistance expert Dr. Ben Bickman and the co-founder of Levels, the continuous glucose monitor company, Dr. Casey Means. If you’re interested in learning about how to keep your FBG in the optimal range (< 80 ng/mL), be sure to check those out.

2. Cardiometabolic Disease. Pizzorno cites a study published in the Journal of the American Heart Association that looked at the number of hospitalizations that occurred in US adults as of November 2020 (3).

The study states that 906,849 COVID-19 hospitalizations occurred in US adults during this time. Because metabolic dysfunction impairs immune function, the authors argue that the high incidence of cardiometabolic disease in hospitalized COVID-19 patients attributed to this population being more susceptible to severe COVID-19 outcomes.

Of the hospitalizations that occurred, an estimated:

  • 20.5% were attributable to diabetes mellitus
  • 30.2% were attributable to obesity
  • 26.2% were attributable to high blood pressure
  • 11.7% were attributable to heart failure

Considered together, 575,419, or 63.5%, of the hospitalizations that occurred in US adults were attributed to these four cardiometabolic diseases. Significant differences were observed in the proportions of cardiometabolic risk-attributable hospitalizations based on age, race, and ethnicity.

Let’s expand on some of these risk factors a little more:

  • High BMI: In his review, Pizzorno underscores a study published in Obesity Medicine that found overweight patients had a 30 percent higher risk of severe COVID-19, and obese patients had a 200 to 250 percent higher risk (4).

Compared to non-obese patients, the risk for infection, hospitalization, disease severity, mechanical ventilation, ICU admission, and death was also remarkably higher (4). Last week I shared a study from Stanford School of Medicine that uncovered the mechanism for why obese individuals are more likely to struggle with COVID-19. Turns out, COVID hides in our fat tissue to evade the immune system and replicate, resulting in a dangerous, highly inflammatory immune response.

Pizzorno references another study published in Endocrinology, Diabetes, & Metabolism that provided insight on why having a higher BMI is linked to more severe COVID-19 outcomes (5). The study looked at the clinical and laboratory data from 610 cases of hospitalized COVID-19 cases in China and found that the following four biochemical markers mediated the effect of BMI on COVID-19 severity the most upon being admitted to the hospital:

    • Blood glucose mediated COVID-19 severity by 79%
    • Lactodehydrogenase (a marker of tissue damage) mediated COVID-19 severity by 78%
    • Hypertension mediated COVID-19 severity by 66%
    • Inflammation (CRP) mediated COVID-19 severity by 44%
  • Diabetes: The risk and severity of COVID-19 increase with increasing FBG in people with diabetes. Compared to non-diabetics, the odds of hospitalization are 400 percent higher, and the odds of severe COVID-19 are 350 percent higher for type 1 and type 2 diabetes (6). Even diabetics who had their blood glucose under control with insulin therapy were still considered high risk (2).

According to the CDC, 90-95% of the 34 million Americans with diabetes have type 2 diabetes, which means the increased risk for hospitalization and severity of COVID-19 was primarily due to insulin resistance (the primary driver of type 2 diabetes) from diet and lifestyle factors.

3. Diet. Poor metabolic health and insulin resistance from eating an ultra-processed, nutrient-poor Standard American Diet contributes enormously to obesity, type 2 diabetes, and heart disease.

For the most part, these chronic diseases are diet and lifestyle-related, which thankfully, are mostly in our control. What we eat, how we live, and how we interact with the world matters, and it’s entirely up to us.

  • Plant-rich diet: Pizzorno presents two papers that establish a link between higher intake of plant foods and lower risk of COVID-19 and severe COVID-19 outcomes. However, it’s worth mentioning that these studies use observational data from food frequency questionnaires and dietary recalls, so the results aren’t incredibly strong.

In one study, the authors argue that eating more plant foods is inherently a good thing when it comes to COVID. A large US and UK population-based study found a 41% lower risk of severe COVID-19 in those who ate more fruits and vegetables (7).

Perhaps the link between higher intake of fruits and vegetables and decreased risk of severe COVID could be due to polyphenols’ healing power that modulates our gut microbiome to improve our immune and overall health?

  • What about protein? The other study found that next to plant-based diets, plant-based pescatarian diets that include fish as a protein source reduced the risk of moderate to severe COVID-19 the most, which was likely due to their higher omega-3 intake (8).

Those who ate more poultry, red, and processed meats and less fruits, vegetables, nuts, and seeds were more likely to get COVID-19. Based on this, the authors concluded that a low-carb/high protein diet presented a greater risk for getting COVID.

But what the authors fail to mention is that the non-plant-based group also ate more refined grains, desserts, and drank more alcohol and sugar-sweetened beverages, which are major contributors to inflammation.

Here’s the point, I’m not sure if it was the high protein diet increasing the risk and severity COVID or that people who eat plant-based diets tend to be more health-conscious and eat more health-affirming foods than those who eat high protein diets, but it’s clear that consuming more whole foods in the form of polyphenol-rich plants are associated with improved outcomes from COVID.

  • Nutrient Deficiencies. Our nutrient status significantly impacts our immune system’s ability to handle COVID-19. If our immune system doesn’t have what it needs to respond appropriately to the virus, we’re going to have a more challenging time fighting it off. It’s like going to war without having the proper ammunition—you’re going to have to put up a much harder fight.

Here are four top-line nutrients Pizzorno mentions in his article:

    • Vitamin D: has gotten a lot of (well-deserved) hype for its role in reducing mortality and adverse COVID-19 outcomes. More than half of hospitalized COVID-19 patients had severe vitamin D deficiency at levels below 20 ng/mL (optimal is 50-80 ng/mL). Supplementing with vitamin D pre-infection reduces the risk of ICU admission by 60 percent and adverse COVID-19 outcome by 75 percent. Plus, it shortens recovery time post-infection.
    • Vitamin C: enhances immune function and is a powerful anti-oxidant. Low levels are associated with a greater risk of infection, severe disease, and death from COVID-19. One report showed that 82% of critically ill patients were vitamin C deficient. In ICU patients, 94 percent had no measurable levels of vitamin C (normal range: 0.4-2mg/dL).
    • Omega-3: adequate dietary intake of omega-3 rich foods, like salmon, sardines, and flax seeds, or taking an omega-3 supplement helps increase omega-3 index (the percentage of omega-3s found in your red blood cells) and is associated with improved viral immunity.
    • Quercetin: binds to the SARS-CoV-2 spike protein and inhibits an enzyme needed for viral replication. Quercetin supplement effectively reduces the length of hospital stay, decreases viral load, and improves symptoms, inflammatory markers, and tissue damage.

Zinc is another keystone nutrient that your immune system needs to help shut down the virus before it starts replicating, and deficiency is super common. For more information about zinc, dosing, and additional recommendations for supplements, phytonutrients, and botanicals like elderberry, the Institute for Functional Medicine put together a top-of-the-line resource guide you can check out here.

4. Air pollution. Particulate matter, or PM2.5, are microscopic airborne particles 2.5 micrometers in diameter or less. PM2.5 is a concerning source of air pollution that comes from dust, spores, pollen, smoke, and burning fossil fuels. In one study, every 1 µg/m3 increase in a 10-year annual average of PM2.5 was associated with an 18 percent higher risk of hospitalization.

Before we get into the protocol, here is a table straight from Pizzorno and colleagues that summarizes the potential risk reduction of severe COVID-19 from modifiable risk factors. You can find all the references cited in the table here.

The Protocol

Today’s protocol is designed to help support your body and restore confidence in yourself and your body’s natural ability to fight off COVID-19 and any future viruses or variants.

I. Eat more plants and healthy fats. The jury’s out! Diets rich in plant foods are associated with less severe COVID-19 infection and improved outcomes. But that doesn’t mean you should skimp out on high-quality protein or healthy fats. Eating a balanced whole foods diet and cutting out processed foods (more on that next) are the most underrated and underreported ways to support your immune health and combat COVID-19.

Try This:

  1. Immune-supporting nutrients:Vitamin D: oily fish (salmon, sardines, mackerel, anchovies, herring), mushrooms, pasture-raised eggs, grass-fed meats, sunshine (even if you live somewhere cold or hazy, getting in two or three minutes of sun is better than nothing!)
  • Vitamin C: red peppers, limes, lemons, oranges, grapefruit, kiwi, broccoli
  • Magnesium: avocado, dark chocolate, pumpkin seeds, almonds (see Try This: Ultimate Magnesium Cheat Sheet for more)
  • Quercetin: apples, parsley, sage, capers, red onion, shallots, scallions, berries, cherries, broccoli, citrus, bell peppers (for more Quercetin-rich foods, click here)
  • Omega-3 fats: the oily fish listed above are the best sources. Chia seeds, flax seeds, and walnuts are also good but less bioavailable (see Try This: Raise Your Omega-3s for more).
  • Zinc: grass-fed beef, pasture-raised chicken, oysters, shellfish, mushrooms, pumpkin seeds, goat’s milk
  1. Test for nutrient deficiencies/metabolic health biomarkers. Knowing where your metabolic health stands and where you might need to increase your levels of specific immune-supporting nutrients is critical.

In a previous newsletter, I wrote all about how to ask your doctor for lab tests that also included the optimal reference ranges for everything from nutrients to cholesterol, fasting blood glucose, HbA1c, and more.

Here are a couple of at-home tests worth considering:

  • Omegaquant: offers a basic and complete omega-3 index test and vitamin D test (no affiliation). Click here to check out Omegaquant‘s testing options.
  • Inside Tracker: an at-home testing company that provides a wide variety of lab tests in exclusive packages that include metabolic markers like LDL, HDL, blood glucose, and nutrients like magnesium, vitamin D, and CRP. You can use my affiliate link to get 25% off Inside Tracker when you sign up.

II. Limit your intake of sugar and processed foods. When increasing your intake of whole foods, you’re going to naturally reduce your intake of refined carbs and sugar from processed foods, a win-win. The problem is, Big Food has made it super difficult to know where and how sugar hides in packaged foods.

Try This:

  1. Simple math equation to identify potentially problematic packaged foods for your metabolic health.

III. Reduce indoor air pollution. We have little control over the air pollution outside. But there’s a lot you can do to clean up the air in your home. Head over to my blog for a comprehensive breakdown on cleaning up your indoor air.

IV. Be mindful of the news you take in. Whether it’s on social media, TV, podcasts, etc., the media we take in is designed to keep our attention. How does it do this? By playing into our negativity bias. This quote sums it up nicely,

“The news, unfortunately, has become a collection of the lowest common denominator of the human experience.” – Rev. Michael Beckwith

The news draws us in with stories that play with our emotions, making us feel scared, lost, and powerless. It’s good to be aware of what’s going on in the world, but there’s such a thing as being too informed. Tuning into the news around the clock has proven to have disastrous consequences for our mental health and well-being. Think about what the world would be like if we didn’t know every horrible thing that was going on.

Try This:

  1. Take a news fast. Pause your news intake for a few days and give your mind and nervous system a break from stimulation. Set some boundaries around news consumption and when you start back up, try limiting your total consumption to about 10 minutes a day.

V. Keep your body moving. Physical activity is the best medicine for long-term health—there’s nothing else like it. Even though Pizzorno didn’t mention it in his paper, a sedentary lifestyle is definitely a modifiable risk factor for COVID.

Studies show that VO2 max, or the maximal oxygen consumption a person can utilize during exercise, is a predictor of severe COVID-19 risk. Having a high VO2 max and some level of cardiorespiratory fitness significantly lowers the risk of death and makes your lungs more equipped to handle a respiratory virus like COVID (9)(10).

Try This: 

  1. Exercise Prescription. If you’re interested in trying an exercise program, here is an example of an evidence-based exercise prescription program formulated by the American College for Sports Medicine. Of course, check with your doctor before starting a new fitness routine and be careful not to overdo it, especially if you are new to it, or have recently had COVID or any other type of respiratory infection.

There’s no “right way” to move, as long as you’re incorporating some kind of regular physical movement throughout the day, your lungs will be in much better shape. Even walking is a simple and effective way to improve your metabolic health and strengthen your cardiorespiratory fitness.

Concluding Thoughts

Mounting evidence is clear that having one or more chronic diseases is associated with more severe COVID-19 outcomes, hospitalization, and even death (1). Unfortunately, the conversation surrounding what causes those comorbidities and what we can do to fix them is virtually nonexistent.

The truth is, there is A LOT you can do to improve metabolic health, reduce your risk of chronic diseases, and in turn, reduce your risk for severe COVID. Through modifiable lifestyle factors, like eating a whole-foods, plant-rich diet, incorporating movement into your daily routine, and supplementing with immune-supporting supplements, you can take charge of your health, starting today.

I never really ask my audience to forward a newsletter, but today I’m going to ask. If you know someone who could benefit from today’s newsletter, it would mean the world to me if you could send it to them.

I also want to thank Dr. Joe Pizzorno for publishing his review paper that inspired this newsletter. If you are interested in keeping up with his work and research you can follow him here.

Here’s to your health,
Dhru Purohit

  1. Mason KE, Maudsley G, McHale P, Pennington A, Day J, Barr B. Age-Adjusted Associations Between Comorbidity and Outcomes of COVID-19: A Review of the Evidence From the Early Stages of the Pandemic. Front Public Health. 2021;9:584182. Published 2021 Aug 6. doi:10.3389/fpubh.2021.584182
  2. Shauly-Aharonov M, Shafrir A, Paltiel O, et al. Both high and low pre-infection glucose levels associated with increased risk for severe COVID-19: New insights from a population-based study. PLoS One. 2021;16(7):e0254847. Published 2021 Jul 22. doi:10.1371/journal.pone.0254847
  3. O’Hearn M, Liu J, Cudhea F, Micha R, Mozaffarian D. Coronavirus Disease 2019 Hospitalizations Attributable to Cardiometabolic Conditions in the United States: A Comparative Risk Assessment Analysis [published correction appears in J Am Heart Assoc. 2021 Apr 6;10(7):e020858]. J Am Heart Assoc. 2021;10(5):e019259. doi:10.1161/JAHA.120.019259
  4. Chowdhury AI, Alam MR, Rabbi MF, Rahman T, Reza S. Does higher body mass index increase COVID-19 severity? A systematic review and meta-analysis. Obes Med. 2021;23:100340. doi:10.1016/j.obmed.2021.100340
  5. Yan H, Vijay A, Jiang F, et al. Serum glucose, lactate dehydrogenase and hypertension are mediators of the effect of body mass index on severity of COVID-19. Endocrinol Diabetes Metab. 2021;4(2):e00215. Published 2021 Feb 16. doi:10.1002/edm2.215
  6. Gregory JM, Slaughter JC, Duffus SH, et al. COVID-19 Severity Is Tripled in the Diabetes Community: A Prospective Analysis of the Pandemic’s Impact in Type 1 and Type 2 Diabetes. Diabetes Care. 2021;44(2):526-532. doi:10.2337/dc20-2260
  7. Merino J, Joshi AD, Nguyen LH, et al. Diet quality and risk and severity of COVID-19: a prospective cohort study. Gut. 2021;70(11):2096-2104. doi:10.1136/gutjnl-2021-325353
  8. Kim H, Rebholz CM, Hegde S, et al. Plant-based diets, pescatarian diets and COVID-19 severity: a population-based case-control study in six countries. BMJ Nutr Prev Health. 2021;4(1):257-266. Published 2021 Jun 7. doi:10.1136/bmjnph-2021-000272
  9. Christensen RAG, Arneja J, St. Cyr K, Sturrock SL, Brooks JD (2021) The association of estimated cardiorespiratory fitness with COVID-19 incidence and mortality: A cohort study. PLOS ONE 16(5): e0250508.
  10. Ahmed I. COVID-19 – does exercise prescription and maximal oxygen uptake (VO2 max) have a role in risk-stratifying patients? [published online ahead of print, 2020 Apr 23]. Clin Med (Lond). 2020;20(3):282-284. doi:10.7861/clinmed.2020-0111
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