Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) has spread worldwide, causing the 2019 Coronavirus Disease Pandemic (COVID-19), with more than 512 million cases and more than 6.2 million deaths so far.
Often the unpredictable severity of the disease is opposed to attempts to predict the outcome of COVID-19, leading to many studies to identify factors that may mitigate the clinical manifestations of the infection.
A new study discusses the role of nutritional factors in this area, concluding
Optimal nutrition remains an effective strategy for maintaining and maintaining a strong immune response that is ready to protect against infections”
Infection with this new coronavirus leads to an intense immune response in a subset of people who rapidly show evidence of systemic hyperinflammation, leading to a rapid deterioration of the clinical condition. This is mediated by the discovery of COVID-19 by macrophages and dendritic antigen-presenting cells that represent viral antigenic peptides of CD4. T cells. This leads to their transfer to Th1 or Th2 cells, secretion of antiviral gamma-interferons (IFN-γ) or induction of an adaptive humoral response, respectively.
Th1 / Th2 balance is essential for virus clearance and clinical resolution, as well as for the return of body systems to normal. Dysregulation of this immune response can cause depletion of T cells and increased inflammatory cascades (so-called. cytokine storm), which leads to severe illness. The mechanism of such a critical disease is vascular damage due to the immune response, which causes acute respiratory distress syndrome (ARDS) and a high incidence of death.
The role of nutrition has been suggested by much earlier studies and is important in light of reduced access to certain foods due to case isolation, contact quarantine and blocking restrictions. This article published online in the magazine Nutrientsreviews the state of current knowledge in this field.
Consumption of fresh fruits and vegetables, which are rich in antioxidants in the form of plant polyphenols, promotes the suppression of inflammatory reactions and oxidative stress. Fish is another source of antioxidants in the form of vitamins and omega-3 fatty acids, which reduce the oxidation of lipids in the cell membrane and the concentrations of pro-inflammatory mediators.
Thus, the Mediterranean diet is associated with adiponectin-mediated increase in insulin sensitivity and reduction of systemic inflammation, lower blood pressure and better arterial compliance, with lower levels of blood glucose, cholesterol and other dangerous lipids. Inflammatory biomarkers such as C-reactive protein (CRP), interleukin-6 and interleukin-8 are also reduced.
More importantly, the Mediterranean diet reduces the risk of rhinitis, asthma and respiratory damage, and even produces an antioxidant effect in children with asthma who have been exposed to air pollution. Studies show that this diet is associated with fewer deaths than COVID-19 in a dose-dependent manner, after compensating for factors such as socioeconomic status, housing and life satisfaction.
In contrast, the Western diet is high in refined sugar and saturated fats and is associated with systemic inflammation. This is probably due to the activation of innate immune cells through Toll-like receptor 4 (TLR4), which ultimately reduces the innate and adaptive immune response through chronic inflammation and oxidative stress. The result is an immunocompromised condition that makes the individual more susceptible to infections as well as damage to multiple organs over time.
In fact, the Western diet is associated with more macrophages in the lungs and increased inflammation of the airways, which acts with a damaged immune response and predisposes to COVID-19 and other viral infections.
Several nutrients and supplements have been found to be useful in improving COVID-19 results. For example, vitamin A levels are higher in those recovering from infection. Vitamin D is an immunomodulator that strengthens the innate immune response while preventing unregulated T-cell responses. High levels of this vitamin can lead to improved fitness.
Regular vitamin D supplementation has been associated with better results than COVID-19, although the evidence is generally weak. Seasonal efficacy also seems to be possible and further research will be needed.
The antioxidant activity exerted by vitamins C and E can protect against cardiovascular damage from free radicals and reactive oxygen species, while reducing systemic inflammation through its suppressive effect on pro-inflammatory cytokines. This can not only modulate the immune response, but also strengthen the lung epithelium against injury. Although they have been shown to be safe and well tolerated, more evidence will be needed to support their routine supplementation in patients with COVID-19.
Glutathione is the major antioxidant defense mechanism in cells, inhibiting inflammatory signaling mediated by NF-κB activation. This molecule is found in high levels in the lung fluid, protecting the epithelium from oxidative damage. Its deficiency is associated with a higher incidence of viral infections with more severe symptoms and worse outcomes.
Here again, promising early results must be supported by larger studies before a therapeutic dose can be reached.
Zinc and other trace elements have also been linked to improved innate and acquired immune responses. For example, zinc can strengthen the epithelial airway barrier, while its deficiency can predispose to viral infection by damaging the barrier. Zinc also promotes the growth, maturation and activation of immune cells, while its immunomodulatory effects are valuable in preventing hyperinflammation.
In addition, zinc has antiviral effects, preventing virus replication as an anti-fusion factor and inhibiting important viral life cycle functions. Zinc levels are associated with a potential improvement in COVID-19 results, although its existence as part of the diet may make it difficult to determine therapeutic levels. Other studies show the potential the effectiveness of omega-3 fatty acids in this state.
Traditional Chinese Medicine (TCM) uses herbal therapies and has been used to treat diseases and foci of infection. This is due to its antiviral, antibacterial and anti-inflammatory actions. Many drugs are available, some of which are adapted for the treatment of COVID-19.
Probiotics are living microbes that form part of the diet, regulating the immune response by acting on interleukins and natural killer cells, as well as T cell differentiation. The relationship between the gut and the lungs makes it important to understand how these microbes affect the immune response.
There is currently some evidence that probiotics are useful in upper respiratory tract infections, but more research is needed to confirm their efficacy and safety in immunocompromised patients.
The results of this review show the role of nutrients in the prevention and management of COVID-9. The superior health profile of the Mediterranean diet and the powerful benefits of many supplements such as antioxidants, vitamin D and probiotics, in terms of their immunomodulatory and anti-inflammatory effects, make it important to understand how supplements with these molecules can help improve COVID-19 results .
Further research in this area, together with a better view of the action of TCM, is needed to benefit from these nutrients in developing a nutritional program that can help build a strong immune response to prevent and clear infectious agents quickly and efficiently.