Nutritional Considerations and COVID-19

By Richard O. Schamp, MD, Chief Medical Officer, Tabula Rasa HealthCare

Recently, I was asked about what nutritional issues might impact a person’s immunity or ability to fight off the SARS-CoV-2 virus. To begin, the emerging literature on patients with COVID-19 indirectly highlights the relevance of nutrition in possibly determining outcomes. Below is a brief summary for some nutritional factors. Understand that while most recommendations are based on associations in relation to non-COVID-19 infections, these have rational underpinnings with low risk of harm.

It’s an ugly fact that most of us may get the SARS-CoV-2 infection at some point. Our metabolic status determines the clinical course of COVID-19. Thus, individual choices that minimize infection risk and modulate the severity of the clinical courses are crucial.

General. Nutrition is strongly linked to immunity. Risk factors for severe COVID-19 illness parallel those for poor nutrition, including older age, multiple chronic medical conditions and lower socioeconomic status. Malnutrition worsens outcomes for nearly all conditions, especially infections. For example, malnourished influenza patients have over ten times odds of death. A diet of high-quality protein, fat, and carbohydrate, maintaining a healthy weight and good metabolic state has many advantages. If someone develops COVID-19, preventing unintended weight loss is important. Minerals and vitamins provided by a healthy diet helps to provide optimal immune cells, antibodies and antioxidants.

Microbiomes. Healthy and diverse intestinal and respiratory tract microbiota are critical factors for the clinical courses of COVID-19, especially in relation to interferons and related immune responses. Host dietary pattern is the pivotal determinant of gut microbiota community, structure, and function. Plant-based diet ingredients modulate microbiomes and provide higher degrees of anti-inflammatory nutrients and fiber to support immune functions. In contrast, the typical high saturated fatty acid western diet is associated with chronic activation of the innate immune system and inhibition of the adaptive immune system, leading to chronic inflammation and impaired host defense against viruses.

Vitamin D. Vitamin D is normally produced in our skin when exposed to sunlight, and in the late winter and spring blood levels of Vitamin D tend to be low (and perhaps in self-quarantine). Systematic reviews support the protective role of Vitamin D supplementation for the prevention of acute respiratory tract infection. COVID-19 virulence mechanisms are reduced upon correction of Vitamin D deficiency. Optimizing Vitamin D may attenuate immune dysfunction that cause poor clinical outcomes in Covid-19 infection, such as prolonged interferon-gamma response and persistent interleukin 6 elevation. People with low Vitamin D levels or at risk of COVID-19 may choose a goal to raise their Vitamin D levels by taking 10,000 IU (250 mcg)/d of vitamin D3 for a couple of weeks to rapidly raise 25(OH)D concentrations, followed by 5000 IU (125mcg)/d. For comparison, single whole-body minimum erythemal dose of sunlight can produce a rise in serum Vitamin D levels which is equivalent to an oral dose of ~250-625 micrograms.

Selenium. Viral infections are associated with selenium deficiency. Researchers recently established a link between COVID recovery and selenium status. Selenium acts mainly through selenoproteins, many of which are antioxidant selenoenzymes. Selenium intake affects immune responses and related mechanisms, suggesting a role for selenium supplementation in viral diseases. Dietary supplements containing up to 200 μg Selenium/d are safe, inexpensive, and widely available with potential as preventives and adjuvants in viral infections.

Vitamin C. The immune-modulating effects in respiratory infection of Vitamin C are well-documented, but supplementation has not shown benefit in prevention or treatment of acute respiratory illness. However, a systematic review showed regular Vitamin C supplementation decreased duration of common cold symptoms. It would be sensible to add this micronutrient to prevent and support the immune responses in the micronutrient-deficit individual at risk for COVID-19.

Zinc. Zinc is an essential trace element which plays an important role in growth, development, and the maintenance of immune function. Zinc deficiency is surprisingly common and impairs antiviral immunity. Zinc inhibits replication of many viruses, including coronaviruses. A meta-analysis of zinc supplementation studies suggested shortened of symptoms and duration of common colds. Therefore, the consumption of up to 40 mg of Zinc per day may provide a protective role against COVID-19, likely by improving resistance against viral infection.

Quercetin. Quercetin is a flavonoid found in many plants and has antioxidant and anti-inflammatory effects. Quercetin has been identified as one of top-scoring candidate therapeutics in the SUMMIT (the world’s fastest supercomputer) expression profiling experiments which could serve in development of efficient inhibitors of the SARS-CoV-2 infection. Quercetin alters expression of 98 of 332 (30%) of human genes encoding protein targets of SARS-CoV-2, thus potentially interfering with functions of 23 of 27 (85%) of the SARS-CoV-2 viral proteins in human cells, especially affecting viral entry into cells. Some experts now recommend doses of 250-500 mg BID.

Many other micronutrients and herbals are touted for prevention during the pandemic. I’ve highlighted those with some reasonable scientific attention. Though we have limited data for the effectiveness of nutrients specific for COVID-19, the above recommendations may have a role in the prevention or mitigation of this disease and are cheap, safe and widely available. Remember that supplements are not a replacement for eating healthy foods.