As of Feburary 2023, the World Health Organization (WHO) reports more than 6.8 million deaths worldwide resulting from the COVID-19 pandemic. WHO cautions that these figures likely undercount the true death toll of the pandemic.
Sadly, the COVID-19 pandemic is far from over: WHO continues to report thousands of new deaths every week. In response, the medical and pharmaceutical science communities are working on developing and improving vaccines and treatments. At the same time, the nutritional science community has been focusing their efforts on unlocking the links between nutrition and COVID-19 susceptibility and COVID-19 severity. Particularly in areas of the world where access to medical treatment is limited, nutrition may play a critical role in disease prevention and mitigation.
Below are a sampling of promising original research studies and reviews published in ASN Journals that help point the way to effective nutritional strategies to alleviate the global burden of COVID-19 disease. For information on how ASN Journals have explored how COVID-19 has affected food insecurity, please visit our previous blog.
- Relationship between Nutrition Therapy in the Acute Phase and Outcomes of Ventilated Patients with COVID-19 Infection: A Multicenter Prospective Observational Study, The American Journal of Clinical Nutrition, January 2022
Optimal nutrition therapy has not yet been established for the acute phase of severe COVID-19 infection. In response, Kensuke Nakamura et al. conducted a prospective observational study to examine the effects of nutrition delivery during the acute phase of COVID-19 on mortality and on post-intensive care (ICU) syndrome, a group of cognitive, physical, and mental health impairments that can occur in patients following ICU discharge. Specifically, the authors examined the effect of nutrition delivery in the first seven days among a group of 297 patients with COVID-19 infection who required mechanical ventilation in one of 32 ICUs in Japan. The nutrition protocol was not defined in this study: nutrition was decided by each attending physician. In general, though, patients were given approximately 20 kcal of energy per kilogram per day and 1 gram of protein per kilogram per day within the first seven days of the acute phase. Results of the study showed that “in patients with COVID-19 on mechanical ventilation for seven or more days, nutrition delivery on days 4-7 was significantly associated with decreased in-hospital mortality after adjustment, but not with post-intensive care syndrome outcomes.”
- The Role of Nutrition in COVID-19 Susceptibility and Severity of Disease: A Systematic Review, The Journal of Nutrition, May 2021
Working with 22 published articles, 38 preprint articles and 79 trials, Philip T. James et al. reviewed the evidence to shed new light on how malnutrition may influence both susceptibility to and progression of COVID-19. The authors found that “there is strong evidence that prevention of obesity and type 2 diabetes will reduce the risk of serious COVID-19 outcomes.” For example, a study of COVID-19 ICU patients in France found obesity to be the most frequent comorbidity among patients. Similarly, in another study, patients with diabetes were found to be more likely to develop severe or critical COVID-19 disease conditions with more complications, including a higher incidence of mortality. The authors did find “limited evidence to date that high-dose supplements of micronutrients will either prevent disease or speed up treatment.” They therefore believe that “the focus should be on ways to promote a balanced diet and reduce the infective burden rather than reliance on high-dose supplementation, until more concrete evidence from clinical trials suggests otherwise.”
- Perspective: Nutritional Strategies Targeting the Gut Microbiome to Mitigate COVID-19 Outcomes, Advances in Nutrition, March 2021
“Gastrointestinal manifestations and gut microbial alterations observed in COVID-19-infected hospitalized patients have raised awareness of the potential role of intestinal mechanisms in increasing the severity of the disease,” according to Laurence Daoust et al. In their review, the authors explored potential nutritional strategies that target the gut microbiome with polyphenols, probiotics, vitamin D and ω-3 fatty acids, with the goal of finding “concrete recommendations that are easily applicable to both vulnerable people with pre-existing metabolic comorbidities and the elderly, but also to the general population.” Although some of these strategies appear promising to prevent COVID-19 or to limit its severity, “the main issue is the lack of well-designed and large-scale clinical studies for us to be able to draw final conclusions and eventually formulate public health recommendations.” As an example, the authors pointed to the proposed use of high doses of vitamin D to protect people from COVID-19, “which can also lead to secondary vascular calcification, a disorder of the blood vessels characterized by a deposit of calcium along the vessel walls.”
- Western Dietary Pattern Antioxidant Intakes and Oxidative Stress: Importance During the SARS-CoV-2/COVID-19 Pandemic, Advances in Nutrition, January 2021
Igor Trujillo-Mayol et al. report that the current COVID-19 crisis has led to high oxidative stress caused by the disease. In addition, measures taken by governments to control the pandemic have led to increased anxiety, stress, and depression, all of which exacerbate oxidative stress, increasing the probability and severity of COVID-19 infection. Although evidence remains scarce, there is some indication that a healthy diet, along with supplemental antioxidant intake, including zinc, selenium, vitamin E, vitamin D and catechins, is beneficial to COVID-19 patients. Even a healthy diet such as the Mediterranean diet, for example, falls short of daily vitamin D requirement, necessitating some level of supplementation. In particular, the authors recommend that “vulnerable populations such as elders and obese individuals could benefit from antioxidant supplementation to improve their antioxidant response.” The authors do, however, note that currently “the required amount of antioxidants in a balanced diet to combat oxidative stress in COVID-19 patients is a question that has yet to be answered.”
We invite you to peruse all four ASN Journals for more information on the bidirectional relationship between COVID-19 and nutrition. A quick search using the term “COVID-19” will lead you to hundreds of articles.
In addition, if you are researching any aspect of the relationship between nutrition and COVID-19 disease, we invite you to submit your findings for publication in an ASN Journal. Our editorial team will ensure that your original research findings or review are quickly disseminated around the world, helping to improve COVID-19 prevention and treatment strategies as well as fuel additional discoveries in this urgent area of nutrition research.