COVID-19 and obesity

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is associated with many comorbidities, including obesity. Obesity itself is favored by many problems that are independent comorbidities such as diabetes, cardiovascular disease, hypertension, fatty liver and respiratory illness.

Adipose tissue and T cells

Obese people have a large amount of body fat, which consists of adipose tissue. Adipose tissue can be classified into three types: white, brown, and beige. White adipose tissue is by far the most common in humans, storing energy in the form of triglycerides and performing a variety of hormonal functions.

Studies in mice have shown that people with abundant white adipose tissue store specific memory T lymphocytes in this tissue after a viral challenge. In other words, secondary infections worsen the immune response and reduce survival.

Conceptual diagram of T cells attacking the SARS-CoV-2 virus. Image Credit: CI Photos / Shutterstock.com

Cytokines and organs

In addition, many cytokines associated with chronic low levels of inflammation are upregulated in obesity: IL-1, IL-6, and TNF-α, among others. Similarly, severe SARS-CoV-2 infection is associated with extensive up-regulation of cytokine production, which, when combined, can cause excessive inflammation throughout major organs.

In the case of COVID-19, there was a large correlation between BMI and the need for mechanical intervention in the hospital. One of the strongest drivers of high mortality observed in obese individuals is the fact that obesity is generally associated with decreased lung function, and lungs are the most severely injured in severe COVID-19 cases. These patients require intubation much more often because they are often injured organs.

Diet and risk factors for SARS-CoV-2

Since SARS-CoV-2 invades host cells by interacting with ACE2 receptors, the abundant ACE2 receptors in specific organs can encourage the virus to target those cells. I will. ACE2 receptors are commonly found throughout the body, especially in the lungs, intestines, and brain.

Obese people are more likely to consume processed foods that are high in fat, salt and sugar and deficient in micronutrients and protein. Interestingly, high sodium consumption is associated with a decrease in ACE2 expressed in the kidneys due to oxidative stress and, in some cases, with more severe stress. COVID19 Symptoms..

Similarly, a low-protein diet is associated with reduced ACE2 expression in the lungs and gut, helping intestinal amino acid homeostasis and the production of antibacterial peptides. Whether carefully selected down-regulation of ACE2 to specific tissues can improve the prognosis of patients by directing the virus to less vulnerable areas of the body is still controversial in the medical community, but eventually. However, undernourishment always produces suboptimal biomechanics.

A low-protein and micronutrient diet is generally strongly associated with impaired immune and anti-inflammatory responses. For example, zinc deficiency causes a decrease in serum IgA, while vitamin C deficiency is associated with decreased interferon production, both of which are essential for the immune response to the virus. Cases of severe SARS-CoV-2 are often the result of extreme inflammation caused by one’s immune system. Vitamin D has been shown to help reduce the severity of the inflammatory response and avoid often fatal lung damage.

Conceptual diagram of SARS-CoV-2 virus that binds to ACE2 receptor on human cells. Image Credit: Kateryna Kon / Shutterstock.com

Immunity and microbiome

The gut flora is also strongly influenced by the individual’s diet, and the microbial flora collected from obese individuals has been shown to affect host immunity by several mechanisms. Many pro-inflammatory and anti-inflammatory cytokines are produced by the microbiota, and poor gut biome health is closely associated with heart disease.

The lung microbiota is indirectly affected by diet and the population of the gut flora. Similarly, a poor lung microbiome reduces the ability to fight respiratory infections.

Conclusion

In conclusion, obese people have been observed to have higher infection and mortality rates for severe COVID-19 than lean people. Obesity, in addition to being a comorbidity in itself, directly induces many other comorbidities that increase the risk of infection and the development of serious symptoms, primarily through defects in the immune response of the body and microbial flora. I will.

Some of the potential ineffective vaccines for obese individuals due to impaired immune response, as demonstrated in the case of vaccines against hepatitis A and B, rabies, and tetanus. There are speculations, but this is not established and applies to any of the COVID-19 vaccines currently on the market.

References

• Silhol, F., Sarlon, G., Deharo, J. & Vaisse, B. (2020) Down-regulation of ACE2 induces overstimulation of the renin-angiotensin system of COVID-19. Need to block the renin-angiotensin system? Hypertension study, 43. https://www.nature.com/articles/s41440-020-0476-3
• Alberca, RW et al. (2020) Obesity as a risk factor for COVID-19: Overview. Critical review in food science and nutrition..https://www.tandfonline.com/doi/full/10.1080/10408398.2020.1775546
• Popkin, BM et al.. (2020) Obesity and COVID-19 Individuals: A Global Perspective on Epidemiology and Biological Relationships. Obesity review, 21 (11). https://onlinelibrary.wiley.com/doi/10.1111/obr.13128

References