COVID-19 is having a significant negative impact on our social and economic lives. Our lives will change. The COVID-19 pandemic should help us—or even force us—to make necessary changes in our lives in order to ensure our future well-being. Both are affected by many factors, and dietary choices are most central. In any stressful situation, it is in the individual’s best interest to be in good health for oneself, family, and society.
While society is suffering from a current acute pandemic with COVID-19, we also have an increasing and chronic pandemic of being overweight and obese (Hales 2017). Obesity and viral infections put a strain on our immune system, contributing to inflammation (Reilly and Saltiel 2017, de Heredia et al. 2012). Aging further compromises immune system functioning (Goldstein 2010), as do other medical conditions (Monteiro and Azevedo 2010). Inflammation is a double-edged sword, protective in cases of injury and infection but antagonizing to health in overweight and obese individuals (Reilly and Saltiel 2017). A chronic elevated inflammatory state is serious for one’s health for many reasons and is the major focus of this column, which addresses the interactions among obesity, the immune system, inflammation, and respiration. All of these physiological functions have a direct impact on COVID-19 infection and recovery.
The advancement of COVID-19 in the lungs deprives an individual of oxygen that can lead to the development of pneumonia, which is an inflammatory condition (Monton and Torres 1998). COVID-19’s attachment on the respiratory system is more severe compared with the flu, possibly requiring longer periods with an oxygen respirator. Obesity compromises the lungs and leads to other respiratory diseases (Zammit et al. 2010).
Inflammation is a normal response to an infectious insult (i.e., bacteria and viruses) or physical insults (i.e., cuts, broken bones, and burns), and the high level of the inflammatory state will eventually subside after these traumas pass (Kokkas 2010). But in the overweight and obese individual, it will not return to its optimum homeostatic level. This is verified by elevated blood levels of pro-inflammatory modulators called cytokines.
Excess weight is the accumulation of body fat and, specifically, the increase in adipocytes (fat cells). Adipose tissue is an endocrine organ, and excess adipocytes will secrete more pro-inflammatory modulators, most notably tumor necrosis factor (TNF-α) and interleukins (i.e., Il-1 and IL-6). Anti-inflammatory modulators (i.e., IL-4 and IL-10) are depressed (Kany et al. 2019). These pro-inflammatory modulators produced in overweight and obese individuals can be considered the negative edge of the immune system’s protective sword. It should be noted that the levels of all cytokines are within a normal range in healthy, weight-managed individuals. Not surprisingly in the current crisis, we are seeing a plethora of unsubstantiated claims on food ingredients and supplements purporting to boost the immune system, but a healthy diet and weight management are the proven first options to improve the immune system. Healthy living habits maintain a robust immune system.
Excess adipocytes also secrete more of the hormone leptin, which helps regulate food intake and energy expenditure. In addition, IL-6 stimulates the liver to produce a family of acute phase proteins in inflammatory conditions. Measurement of these C-reactive proteins and the cytokines mentioned are often used to indicate an inflammatory state in an individual (Kany et al. 2019, Sproston and Ashworth 2018). The inflammatory state also represses the production of adiponectin that regulates glucose and lipid metabolism, insulin sensitivity, and food intake. Knowledge of this hormone and its effect on blood glucose and insulin level helps explain the development and treatment of Type II diabetes (Abdella and Mojiminiyi 2018).
In obesity, the respiratory system is also compromised as evidenced by breathlessness and exertion (Zammit et al. 2010). Type II diabetes progresses in overweight individuals (prediabetic) and is more pronounced in those who are obese. Respiration and pulmonary functions are diminished in the diabetic lung (El-Azeem et al. 2013). The connections and negative interactions among the common metabolic diseases like Type II diabetes, obesity, elevated conditions of inflammation, and impaired respiratory function come together in helping to understand how treatment and recovery from COVID-19 can be impaired.
Increased inflammation is now considered as the initiating condition in many metabolic diseases (Ellulu et al. 2017). The significance of these cytokine risk factors in association with diseases has been advanced (Katsiari et al. 2019). The initial question or debate centered on whether the elevated levels of these cytokines have a direct impact on causing a disease or are just a secondary effect of the immune system. All these pathophysiological markers are present leading to atherosclerosis: Dysfunctions are observed along with oxidative stress in vascular endothelial cells. There is macrophage accumulation, formation of inflammasomes, and production of the pro-inflammatory cytokines (Guo et al. 2015). The convincing evidence as to the direct benefit of lowering these pro-inflammatory cytokines is that anti-TNF-a and anti-IL-6 drugs can control atherogenesis and reduce cardiovascular risk (Low et al. 2017).
Initial refence was made to the fact that our health and well-being are affected by our dietary choices. Our food supply can and does provide for healthy diets. Healthy diets help manage one’s weight and thus support a normal and robust immune system. Reduction of chronically elevated blood pro-inflammatory modulators can be diminished with drugs (Low et al. 2017), but weight management should be the first preventive treatment.
In summary, the biochemical and physiological factors in the development of common diseases are immense and complicated. The evidence is growing to suggest that individuals with a chronic inflammatory state are at higher risk if infected with COVID-19. Being overweight or obese leads to and maintains a chronic inflammatory state. Along with many sites in the body, the lungs are stressed. Respiration is impaired. The obesity pandemic appears to be hampering prevention of COVID-19 and recovery from it.
We are fighting two pandemics. Changes might be difficult but will be required. IFT and its members have an important role in providing foods for good dietary choices, and these foods contribute to our health. This message must be constantly promoted through education, and IFT and its members can do this. Being in good health is life’s best primary prevention of disease and the management of any disease. The best state of health is observed in the weight-managed individual.