AgCenter scientist exploring how diet, gut health affect COVID-19 severity

(02/26/21) BATON ROUGE, La. — An LSU AgCenter researcher wants to find out whether eating a plant-based diet and having a healthy gut can reduce the severity of a COVID-19 infection.

Jack Losso, a professor in the School of Nutrition and Food Sciences, has long been intrigued by the links between what people eat and how it affects their health. When he noticed that coronavirus infection and death rates are lower in areas where people tend to have more plant-based diets, he knew he wanted to study the correlation further.

“When you take populations that are relying on plants for a lot for their diet, the rate of infections and death is very low,” Losso said.

He pointed to the Blue Zones — places where many people live longer than usual — as an example. Despite having an older population, these zones have had comparatively fewer COVID fatalities than many other areas of the world, Losso said. The Blue Zones include Okinawa, Japan; Loma Linda, California; Nicoya, Costa Rica; Ikaria, Greece; and Sardinia, Italy.

“Besides old age, some of the risk factors for COVID are obesity, diabetes and hypertension,” he said. “The rates of those conditions are low in the Blue Zones compared to most of the rest of the world.”

Losso has completed an extensive literature review and is diving into his own study of how diet affects gut health, which in turn can affect how well a person’s body handles a coronavirus infection.

“A plant-based diet helps gut microbiota,” he said. “When the gut is affected, the lungs are affected and vice versa.”

He explained that 70 to 80% of the body’s immune system is in the gut, or gastrointestinal tract. The immune system can be weakened if there is a microbial imbalance in the gut — a condition known as dysbiosis, which is common in people with diabetes and other conditions that put them at risk for more severe COVID cases.

Eating a lot of foods that are high in fat and sugar can hinder gastrointestinal health, he said. Proteins and fiber that come from plants, on the other hand, are good for the gut.

Losso wants to explore another possible benefit of certain plant-based foods: compounds that may help the body ward off infection by preventing the coronavirus from bonding to ACE2 receptors. These receptors are proteins found on the surface of cells, and they are plentiful in the lungs and gastrointestinal tract.

Some foods are known to inhibit certain enzymes, Losso said. For example, sweet potatoes, soy products, bananas, squash, zucchini and some beans contain inhibitors of trypsin, an enzyme that breaks down proteins.

Because enzymes prime the coronavirus for bonding to receptors and entering the body, it’s important to examine foods that might be able to stop that process, he said.

Even though vaccines have been developed and are beginning to be administered, Losso said, it’s still a good idea to study other methods of potentially controlling the virus. He wants to use his expertise in food science to make a contribution.

“We’re not saying people are not going to be infected,” he said. “But when you combine this with masks and social distancing and proper handwashing, maybe we can reduce the severity of infections and fatalities. And people can get better and go back to school and their occupations, and that’s what we want.”

Jack Losso.

LSU AgCenter food scientist Jack Losso. LSU AgCenter file photo

2/26/2021 1:59:17 PM
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