Optimal - The Blog

August 17, 2021

Optimal Takeaways: Improve Immunity & Reduce Susceptibility to COVID-19

Optimal Takeaways for Improving Immunity and Reducing Susceptibility to COVID-19

Beth Ellen DiLuglio, MS, RDN, LDN

Although the SARS-CoV-2 virus that causes COVID-19 appears to be a covert, unstoppable intruder, that doesn’t mean that we can’t fortify our defenses to try and stop it in its tracks.

Adopting healthy changes in diet and lifestyle can also reduce your risk of the comorbidities associated with severe COVID-19: [1] [2] [3] [4] [5] [6] [7] [8]

  • Age greater than 50
  • Cancer
  • Cardiovascular disease
  • Chronic lung, kidney, or liver disease
  • Diabetes mellitus
  • Exposure to pollution
  • Hypertension
  • Lack of sunlight exposure
  • Lifestyle factors, smoking, excessive alcohol intake
  • Obesity, especially BMI of greater than 30
  • Oxidative stress
  • Unhealthy Western-style diet
  • Vegetarian diet if low in B12, zinc, copper, iron, selenium, vitamin D, and omega-3 EPA and DHA

Here are some optimal takeaways for improving your immune defenses against COVID-19:

  • Diet, nutritional status, and lifestyle are modifiable risk factors for COVID-19 and its comorbidities. These factors should be highlighted in public messaging about the COVID-19 pandemic.
  • Biomarker clues can provide insight into the severity of COVID-19 as well as underlying nutrient insufficiencies and deficiencies.
It is imperative that assessment of key biomarkers and nutrients be part of COVID-19 evaluation, monitoring, and therapy, especially:
  • Inflammatory markers
  • Transaminase enzymes
  • LDH
  • Fibrinogen
  • WBC differential
  • Neutrophil:lymphocyte ratio
  • IL-6, IL-10
  • Albumin, prealbumin
  • Vitamin C
  • Vitamin D
  • Selenium
  • Zinc

Remember that optimal lab ranges are narrower than standard lab ranges and may give earlier clues to imbalance or deficiency.

A healthy dietary pattern modeled on the Mediterranean diet or DASH diet can help reduce the risk of chronic metabolic diseases and in turn, reduce the risk of severe COVID-19:

  • Minimum of 4 servings of fruit, 5 servings of vegetables during COVID and beyond
  • Adequate whole grains, meats, beans, dairy, protein, whey protein
  • Incorporate herbs, spices, tea, coffee daily
  • Minimum of 35 grams of fiber daily, ideally from whole foods, can supplement with psyllium
  • Include fermented foods, probiotic-containing foods
  • Adequate micronutrient intake particularly vitamins A, Bs, C, D, E, zinc, and selenium
  • Minimize or eliminate highly processed foods, added sugars and salt, excessive saturated fats, fatty processed meats
  • Targeted nutrition support should be utilized:
    • A high-potency multivitamin-mineral supplement can provide a foundation with additional micronutrient supplementation as needed

Other factors should be considered in the fight to prevent and treat COVID-19 including:

  • Sleep hygiene
  • Stress management
  • Mental health
  • Social connections
  • Environmental factors, clean air, clean water, clean food
  • Health literacy

Finally, be aware that a variety of adverse outcomes can persist even after perceived recovery from COVID-19 and can include:

  • Adverse cardiovascular outcome’s
  • Adverse psychological outcomes
  • Adverse neurological complications
  • Adverse gastrointestinal complications
  • Adverse cutaneous complications
  • Adverse effects on food supply and food security


[1] Ejaz, Hasan et al. “COVID-19 and comorbidities: Deleterious impact on infected patients.” Journal of infection and public health vol. 13,12 (2020): 1833-1839. doi:10.1016/j.jiph.2020.07.014

[2] Gallo Marin, Benjamin et al. “Predictors of COVID-19 severity: A literature review.” Reviews in medical virology, e2146. 30 Jul. 2020, doi:10.1002/rmv.2146

[3] Richardson, David P, and Julie A Lovegrove. “Nutritional status of micronutrients as a possible and modifiable risk factor for COVID-19: a UK perspective.” The British journal of nutrition, 1-7. 20 Aug. 2020, doi:10.1017/S000711452000330X

[4] Nandy, Kunal et al. “Coronavirus disease (COVID-19): A systematic review and meta-analysis to evaluate the impact of various comorbidities on serious events.” Diabetes & metabolic syndrome vol. 14,5 (2020): 1017-1025. doi:10.1016/j.dsx.2020.06.064

[5] Albitar, Orwa et al. “Risk factors for mortality among COVID-19 patients.” Diabetes research and clinical practice vol. 166 (2020): 108293. doi:10.1016/j.diabres.2020.108293

[6] Zheng, Zhaohai et al. “Risk factors of critical & mortal COVID-19 cases: A systematic literature review and meta-analysis.” The Journal of infection vol. 81,2 (2020): e16-e25. doi:10.1016/j.jinf.2020.04.021

[7] Hernández-Galdamez, Diego Rolando et al. “Increased Risk of Hospitalization and Death in Patients with COVID-19 and Pre-existing Noncommunicable Diseases and Modifiable Risk Factors in Mexico.” Archives of medical research vol. 51,7 (2020): 683-689. doi:10.1016/j.arcmed.2020.07.003

[8] Baradaran, Ashkan et al. “Prevalence of Comorbidities in COVID-19 Patients: A Systematic Review and Meta-Analysis.” The archives of bone and joint surgery vol. 8,Suppl 1 (2020): 247-255. doi:10.22038/abjs.2020.47754.2346

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