Viral respiratory diseases, such as seasonal flu or COVID-19, are deadly scourges for society. Immunometabolic therapies can be important tools to reduce the death burden and long-term disability caused by pandemic viruses. Recent studies defend the biological effects of ketone bodies , the natural metabolites produced during fasting or carbohydrate restriction, which maintain cellular energy but also present drug-like signaling activities that affect immune activity, metabolism and expression. gene.
How do ketones influence the body?
Several biological actions of ketones may be therapeutically relevant to populations at increased risk of respiratory viral infection, but have not been tested in this setting; Other actions may have counterproductive effects. In particular, ketones can now be easily administered using exogenous ketone compounds, making it a promising area for future research.
Viral respiratory infections remain a negative occurrence in society, with seasonal flu infecting millions and killing many thousands annually, and viral pandemics, such as COVID-19, recur every decade. Age, cardiovascular disease, and diabetes are risk factors for serious illness and death from viral infection. Immunometabolic therapies for these populations promise to reduce the risks of death and disability.
Such interventions have pleiotropic effects, which could not only target the virus itself, but also improve supportive care to reduce cardiopulmonary complications, improve cognitive resilience, and facilitate functional recovery. Ketone bodies are endogenous metabolites that maintain cellular energy, but also exhibit drug-like signaling activities that affect immune activity, metabolism, and epigenetics.
In the current COVID-19 pandemic, governments demand social distancing and good hand hygiene, but little attention is paid to the potential impact of diet on health outcomes. Poor diet is the factor that contributes the most to the burden of chronic lifestyle-related diseases, such as obesity, type 2 diabetes and cardiovascular disease.
Hospitalizations for coronavirus were six times higher among patients with a reported underlying condition (45.4%) than those without reported underlying conditions (7.6%). Deaths were 12 times higher among patients with reported underlying conditions (19.5%) compared to those without reported underlying conditions (1.6%). Two thirds of people in the UK who became seriously ill with COVID-19 were overweight or obese and 99% of deaths in Italy have been in patients with pre-existing conditions such as hypertension, diabetes and heart disease . These conditions, collectively known as metabolic syndrome, are related to impaired immune function, and more serious symptoms and complications of COVID-19.
An important factor driving the pathophysiology of metabolic syndrome is insulin resistance , defined as an impaired biological response to insulin, the hormone that regulates blood glucose levels. Deregulation of blood glucose levels plays an important role in inflammation and respiratory diseases. A study of COVID-19 patients with pre-existing type 2 diabetes showed that those with better regulated blood glucose control performed better than those with poor blood glucose control. Specifically, well-controlled blood glucose (glycemic variability within 3.9-10.0 mmol / L) was associated with reduced medical interventions, major organ injury, and all-cause mortality during hospitalization, compared to individuals with poorly controlled blood glucose (glycemic variability greater than 10.0 mmol / L). Another study showed that hospitalized hyperglycemic patients treated with insulin infusion had a lower risk of death from COVID-19 than patients without insulin infusion, likely due to reduced inflammatory mediators.
The most significant factor that determines blood glucose levels is the consumption of carbohydrates in the diet , that is, refined carbohydrates, starches and simple sugars. However, the official dietary recommendations of most Western countries advocate a reduced (low) fat and high carbohydrate diet, which can exacerbate hyperglycemia. These dietary guidelines form the basis of menus in nursing homes and hospital wards where people with COVID-19 and pre-existing metabolic syndrome are recovering and breathing.
The problem is not just limited to nursing homes and hospitals. As people self-isolate at home, many stock cheap, non-perishable staples like pasta (rich in carbohydrates), bread, rice, and cereals. Our food supply is dominated by highly processed and packaged foods.
The ketogenic diet may be a protection against COVID-19
As the world faces rapid transmission of a new virus, there has been little opportunity to conduct trials on whether COVID-19 patients perform better on low-carb diets compared to other diets. However, there is strong evidence that dietary carbohydrate restriction is a safe and effective way to achieve good glycemic control and weight loss , and to reduce the need for medications in the treatment of type 2 diabetes.
Low-fat diets showed that low-carb diets were superior in achieving glucose control, as well as in limiting short and long-term cardiovascular risk factors for people with type 2 diabetes.
There has been little willingness to accept the benefits of low carbohydrate diets, primarily due to contradiction with official dietary guidelines that recommend carbohydrates make up 45 to 65 percent of total daily calories , but an significant progress in recent years. For example, in 2018, Diabetes Australia issued a position statement indicating that there was reliable evidence that a low carbohydrate diet can be safe and useful in reducing blood glucose levels, reducing body weight, and controlling risk factors. from heart conditions like high cholesterol and high blood pressure. In addition, in 2019, the American Diabetes Association and in 2020 Diabetes Canada, endorsed low carbohydrate diets as a viable option to improve blood glucose and the potential to reduce medications for people with type 2 diabetes.
Dietary carbohydrate restriction is a simple and safe intervention that results in rapid improvements in glycemic control and can be implemented in conjunction with usual care in a medical or home setting. Although the pathophysiology of COVID-19 is multifactorial, insulin resistance is among the strongest determinants of impaired metabolic function . Given that much of the world's population is not metabolically healthy, the extent to which it contributes to the severity of COVID-19 infection is likely to be significant.
