Used with permission by the Academy of Nutrition and Dietetics
Like all upper respiratory viral infections, SARS-CoV-2 — aka Covid-19, aka corona virus — affects groups of people differently. Young and healthy people may not even show symptoms. Frail elderly people with preexisting medical problems may develop severe and life threatening complications, predominantly pneumonia. Covid-19 is especially dangerous for people with hypertension. Why is that?
This variant of the corona virus family has only been recognized since January, so it’s remarkable that scientists already know so much about how it does its dirty work. I found a really nerdy description of the process by which the Covid-19 gets into a cell in The Economist. The article is behind a pay wall, but this sort of Virus 101 information can be found elsewhere in virology and infectious disease literature. I’ll try to sum it up in simple terms.
You have to understand that the cells in our bodies are not little balloon-like bags full of liquid. The outer membrane is an active part of the cell, with protrusions and indentations and portals and pumps imbedded in the membrane structure. These are designed to lock together with specific molecules inside and outside the cell. Some molecules are allowed to enter the cell, others are moved out; some molecules create a chemical message by attaching to a receptor, telling the cell to perform some metabolic function. It’s really quite an ingenious system.
So along comes a Covid-19 virus. It can’t do anything until it gets into a cell, so like other viruses, it has a specific way to hijack one of the cell’s entry control systems. This particular virus hijacks what is called the ACE2 receptor. Many types of cells have these unique receptors, and they are especially abundant on cells of the respiratory system. A region on the virus fits into that receptor’s shape like a puzzle piece, which starts a chain of events on the membrane that allows the virus into the cell. Once in the cell, the virus uses the cell’s replication equipment to make more copies of itself, leading to an inflammatory response.
You may be familiar with the term ACE2, particularly if you have hypertension, because some blood pressure drugs are known as ACE2 inhibitors. These medications interfere with ACE2 receptors; the result is relaxation of blood vessel walls and lower blood pressure. As I said, ACE2 receptors are particularly common on cells in the respiratory system, which might explain why common Covid 19 symptoms include coughing and shortness of breath. But while the link between hypertension, ACE2 receptors and Covid-19 is known, the reason for this link is not known. Will that information help with treatment or prevention. We don’t know yet.
What does all this have to do with nutrition? The most common causes of hypertension are lifestyle risk factors, diet in particular. Obesity is the primary risk factor. Losing weight leads to lower blood pressure, although the degree of improvement will vary from one person to another. Sedentary lifestyle is another risk factor. Adding regular meaningful exercise helps lower blood pressure. Of course,