Your Personal Risk of Illness from COVID-19

COVID-19 riskI’ve been watching some great webinars presented by the Institute of Functional Medicine, that summarize current research about COVID-19. The science is piling up to support what many of us know to be true for other infections: our lifestyle habits play a key role in risk of developing severe illness, and we have more control over our risk than commonly acknowledged.


Here are some research highlights that might surprise you:

  • People who enjoyed a plant-based diet enjoyed an approximate 73% reduced odds of serious illness, compared to a 3.9-fold increased risk for people who ate a lot of meat.
  • People who were deficient in vitamin D had a 3.87-fold increased risk of death from Covid-19, independent of other health concerns like diabetes and lung or heart disease.
  • Supplementing with vitamin D during or after illness might not make a difference. Adequate vitamin D levels heading into an illness may be what matters most. There are a variety of lifestyle habits that support optimal vitamin D levels (hint: inflammation is correlated to vitamin D deficiency).
  • People with severe Covid-19 were much more likely to have very low vitamin C levels in their blood but, interestingly, supplementing with vitamin C during or after illness didn’t impact outcomes much. Perhaps it’s because vitamin C deficiency reflects (i.e. is a biomarker of) high levels of inflammation (oxidation) in the body. This too, can be significantly impacted by lifestyle choices.
  • If you’re overweight, your risk of severe illness goes up 30%. If you’re obese (often defined as a BMI over 30), your risk goes up 3.80 fold and ICU admission goes up 2.25-fold. If you have diabetes (type 2), your risk goes up 3.36-fold.


Of course, none of this research is perfect and there are a lot of gaps in our understanding. And as is the way with scientific research, the consensus might swing further away from or in support of these findings as research accumulates. Certainly there are people who criticize findings like these as irresponsibly encouraging people to misuse supplements and make poor lifestyle choices in advance of a scientific consensus. The caveat here I suppose is: if in doubt, contact a knowledgeable healthcare provider.

However, the important underlying message is that our vulnerability to illness is significantly impacted by our current health status, and this is very well known to be modified by our day-to-day choices. Simple measures like 10 minutes of daily exercise where none existed before, or blood tests for vitamin D or insulin levels, or reduced EMF exposure, could have a real impact on immune system health and disease resilience. If you struggle with food choices, have you considered working with a holistic nutritionist to find a way to enjoy healthy foods that balance your blood sugar and reduce inflammation?  And if focusing on lifestyle changes now are too stressful, perhaps it’s time to focus on how your body responds to stress, since stress contributes to every one of the deficiencies and metabolic imbalances listed in the research above. (Take the Stress Questionnaire on our assessment page as a place to start.) When it comes to immune system resiliency, every step towards a happier, healthier lifestyle, counts.


Additional Resources:

COVID-19 and your immune system

Natural Prevention Urgently Required, Dr. Sonya Nobbe, ND

Boosting your Immunity, Trish Krause

Pandemic of Virology or Toxicology (for health practitioners)



Cai Z, Yang Y, Zhang J. Obesity is associated with severe disease and mortality in patients with coronavirus disease 2019 (COVID-19): a meta-analysis. BMC Public Health. 2021;4(21):1505.

De Smet D, De Smet K, Herroelen K, et al. Serum 25(OH)D Level on Hospital Admission Associated With COVID-19 Stage and Mortality. American Journal of Clinical Pathology. 2021;155(3):381–388.

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 DiabetesDiabetes Care. 2021;44(2):526-532.

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 Nutrition, Prevention & Health. 2021; 4.

Tomasa-Irriguible TM, Bielsa-Berrocal L. COVID-19: Up to 82% critically ill patients had low Vitamin C valuesNutr J. 2021;20:66.


*Photo by Alois Komenda on Unsplash

immune system

Dr. Sonya Nobbe, ND

Dr. Sonya Nobbe is a Naturopathic Doctor and Director of Kingston Integrated Healthcare Inc. She has been practicing in the Kingston area since 2007. Dr. Sonya maintains a family practice, with a clinical focus on complex chronic disease, including Lyme disease and Fibromyalgia.


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