Food Insecurity Caused by Coronavirus May Have Long-Term Health Consequences
(October 16, 2020) — As a postdoctoral research associate in nephrology and hypertension, Aline de Souza, PhD, studies the long-term impact of drastic weight loss due to severe calorie restriction with Kathryn Sandberg, PhD, professor and vice chair for research in the Department of Medicine.
When studying female rats that experienced severe calorie restriction, de Souza found evidence that they were more likely to develop cardiovascular disease than the control group months after they had regained the lost weight.
Her findings may have implications for those struggling with food insecurity due to the coronavirus pandemic. According to the USDA, 5.3 million American households struggled with very low food security in 2019, meaning that their normal eating patterns were disrupted and their food intake decreased. Recently, the Institute for Policy Research at Northwestern University estimated that food insecurity has doubled due to the pandemic.
“We’re all thinking about the acute effects of COVID-19 but I think we also need to start thinking about the long-term repercussions in terms of human health,” Sandberg said.
With a background in nutrition, de Souza wanted to study what happened to people who had recovered from restrictive diets, such as those associated with eating disorders. “Women who have anorexia are studied by cardiologists when they’re sick, but when they get past the acute phase, there’s no follow-up,” Sandberg said. “Once we get them out of the woods, that’s it. People don’t ask those with cardiovascular disease if they had anorexia.”
However, de Souza’s research has applications for those who experience severe calorie restriction for any reason, not just eating disorders. “Our model is not just anorexia,” she said. “It’s any situation with drastic weight loss due to low food intake, such as in food insecurity.”
Recognizing that women are more likely than men to restrict their calories significantly, de Souza used female rats in her research. After receiving a standard diet for two weeks, the experimental group of rats was given 60% less food for two weeks before being returned to a standard diet. Within two weeks of returning to their standard diet, the rats regained the weight they had lost while their food had been restricted.
Three months after the food restriction ended, the rats had returned to their normal body weight. But they had more abdominal fat, and their renin-angiotensin system, a hormone system that regulates blood pressure and fluid balance, remained hyper responsive. Specifically, the rats’ plasma angiotensinogen, angiotensin II and angiotensin enzyme activity remained elevated, putting them at risk of developing cardiovascular disease.
“After seeing the high angiotensin system responsiveness in our re-fed rats, we believe that people who had periods of low food intake have higher predisposition to develop hypertension and heart problems or have less cardiovascular resilience to stressful events,” de Souza said.
Future Research Directions
De Souza’s publication in the Journal of the American Heart Association bolsters a study from Sandberg’s lab published earlier this year in Experimental Physiology that found male rats who went through a similar period of severe calorie restriction were more likely to experience cardiac arrhythmias.
Next steps for the researchers include researching whether severe calorie restriction affects male rats differently compared to female rats. “Anorexia and diets to lose weight are more common in women, which is why we chose that model,” de Souza said. “But now we are comparing males and females to see if they are different when they lose weight.”
Researchers are also studying ways to prevent damage to the cardiovascular system with existing drugs. “If it turns out that they’re protective, maybe there could be some studies where we could easily inform a clinical trial,” Sandberg said. “We don’t have to discover a new drug. We have drugs already out there that we think could be the answer.”
“What Aline’s work is showing is that there’s a problem that we may not see right now but may show up in 10-20 years,” Sandberg said. “And we think it’s really important to do research in this area.”