Obesity and COVID-19: a dangerous duo
Older people are hit hardest by the coronavirus, but by far the second most prevalent group is people with obesity. They are more likely to contract a severe case of COVID-19, and more likely to die from it. Gijs Goossens, associate professor of Human Biology, is studying whether drugs that lower blood pressure can reduce the risks. “Obesity is a major risk factor, so I would like to see the media emphasise not only the prevention of infection, but also the importance of a healthy lifestyle when people are working from home or are in quarantine.”
Of the Dutch population, 50% are overweight and 14% obese. These numbers, Goossens fears, will only increase with the current pandemic and the accompanying pile-on of ‘corona kilos’. “The lockdown measures and quarantines have an impact on physical activity and eating behaviour. Sports activities and treatment programmes for obese people—which are often organised in groups—have been severely restricted. Even in the short term, this can increase the risk of cardiometabolic disorders. And self-isolation means that people are eating more food with a longer shelf life instead of fresh produce. These foods often contain more salt and fat; cause for concern when you know that every extra kilo can lead to additional health problems.”
Fat tissue is a metabolic organ
Goossens’s research focuses on the metabolic phenotyping of people with overweight and obesity. In other words, he tries to shed light on what goes wrong in the metabolism and how this can differ from person to person. “Up to 30% of obese people are still ‘metabolically healthy’: they don’t have high blood pressure and the amount of fat and sugar in their blood is in the normal range. On average, however, they are much more likely to develop type 2 diabetes and cardiovascular disease within 10 years. Why one obese person develops certain diseases more quickly than another relates to factors such as age and gender. What seems to play a key role in this is the ‘health’ of the adipose tissue—that is, fat—and its distribution around the body.”
Gijs Goossens is associate professor of Human Biology at NUTRIM. He studied Health Sciences at Maastricht University, where he obtained his PhD in 2006 for his dissertation ‘The metabolic and haemodynamic effects of the renin-angiotensin system in obesity.’ He is chair of the Scientific Advisory Board of the European Association for the Study of Obesity (EASO) and, until July 2020, also chaired the Netherlands Association for the Study of Obesity (NASO).
Over the last 15 years, Goossens has seen a rise in studies focusing on the biology of the adipose tissue. “Fat is really a metabolic organ; it not only stores excess calories, but is also involved in many physiological processes in the body. For example, obesity is associated with more inflammation of the adipose tissue and a less effective immune system: the more adipose tissue, the more inflammation. This contributes to disturbances in the metabolism of sugar and fat, which increases the risk of cardiovascular disease and type 2 diabetes. Meanwhile, it has become clear that obesity in particular—along with lung diseases, type 2 diabetes and high blood pressure—leads to more severe symptoms and a higher risk of death from COVID-19. Obese people often have more virus particles in their body, and these particles stick around longer than in people of normal weight. Obese people have a less effective immune response: the immune system produces many inflammatory factors to suppress the virus. In severe cases of COVID-19, this results in what’s known as a ‘cytokine storm’: an uncontrolled release of inflammatory molecules that spread throughout the body, leading to organ damage.”
Adipose tissue as a possible reservoir for the virus
In the first quarter of 2021, Goossens hopes to publish the results of his research into the effect of valsartan on the number of ACE2 receptors in the abdominal fat of obese people. Valsartan is an angiotensin II type 1 receptor blocker that lowers blood pressure. Could this drug contribute to better treatment for COVID-19? “ACE2 is part of what is known as the renin–angiotensin–aldosterone system (RAAS). The ACE2 receptor, the gateway for the SARS-CoV-2 virus responsible for COVID-19, is also present on fat cells. We suspect that the increased fat mass in obese people can serve as a reservoir for the SARS-CoV-2 virus to multiply,” Goossens says. “In previous research, we showed that valsartan not only reduced blood pressure, but also had a positive effect on sugar metabolism. We also saw a reduction in certain inflammatory cells in the adipose tissue.” If this tissue is indeed a reservoir for viral replication that contributes to the intense inflammatory reactions in patients with COVID-19, then—so the theory goes—RAAS blockers like valsartan could influence the multiplication process and thus the course of the disease. “It won’t be the magic bullet, but it could help to optimise the treatment of COVID-19 patients. Several clinical studies are already underway. Our research will contribute to a better understanding of how this process may work.”
Wake-up call
Goossens, who is also chair of the Scientific Advisory Board of the European Association for the Study of Obesity (EASO), recently discussed the relationship between obesity and COVID-19 with the World Health Organization. He stresses the urgency of action against the double obesity–COVID-19 pandemic. “The problem should be tackled at different levels in society. It starts with you: in just a few weeks, a healthy diet, stress reduction, and adequate sleep and exercise can lead to weight loss, lower blood pressure, better regulation of sugar levels and improved functioning of your immune system. But the obesity problem also requires an integrated approach by the government: developing a healthier living environment by creating more playgrounds for children, incentivising product improvement and adjusting the tax on healthy and unhealthy foods. I hope the COVID-19 pandemic is a wake-up call that accelerates the fight against obesity. It’s time to join forces and devote more energy to the prevention and treatment of obesity.”