The following is an adapted excerpt of my latest book, The New Heart Health, which I coauthored with my colleague, Dr. Andrew Myers. The book is a new approach to cardiovascular wellness, drawn from my Nobel Prize-winning research and Dr. Myer’s expertise in natural medicine.


What Is the Endothelium?

The endothelium is an organ system within the cardiovascular system. The cardiovascular system is made up of the heart and a system of blood vessels composed of arteries, veins, and capillaries. The arteries carry oxygen-rich blood (thanks to oxygen from the lungs) from the heart to the rest of the organs and tissues in the body through tiny capillaries, which release the oxygen to the cells and take up carbon dioxide. Blood then flows from the capillaries into the veins and travels back to the heart to be reoxygenated. This entire process takes about a minute, depending on how active you are; the more you move, the faster your blood flows.

More information about the structure and function of the endothelium can be found in The New Heart Health.

More information about the structure and function of the endothelium can be found in The New Heart Health.

Here’s where the endothelium comes in. Your body contains six trillion endothelial cells that line one hundred thousand miles of blood vessels in a single layer; that continuous layer throughout the vascular system (the arteries, veins, and capillaries) makes up the endothelium.

The main job of the endothelium is to create the signaling molecule Nitric Oxide (NO), a crucial molecule in the cardiovascular system.

The endothelium extends throughout the entire body but has different functions in different parts of the body. Endothelial cells function differently in the brain, for example, than in the liver, kidney, or lungs. But that’s another topic and another article—for now, we’ll focus on the endothelium’s role in the cardiovascular system.

We mentioned that the endothelium is a component of the cardiovascular system but also a separate organ. Because endothelial cells form a communicative layer—one touching another throughout the entire body—they’re considered a single entity. This shakes up what most people know about organs. After all, what do you think of when you hear the word “organ”? The liver, the lungs, the heart—basically, a singular mass within the body that you could put your hands around. The research community even used to think the endothelium was simply a protective layer within the blood vessels. It took decades for scientists to finally recognize that the endothelium is a communicative layer of cells, one organ that has its own unique function within the body. And, as it turns out, the organ also has an important role in the cardiovascular system.

Why are the endothelial cells so important? Along with helping to regulate blood flow, the endothelium is the factory that produces and releases NO and a handful of other hormones and chemicals that influence all aspects of cardiovascular health.

Actually, you could even say the endothelium is life-giving. During the fetal period, the vascular system, lined with the endothelium, is one of the first developments in a growing baby. The blood vessels are necessary to the development of the fetus because blood provides the nutrition and oxygen—basically everything a developing human needs to grow—and removes the cellular toxins and waste out of the body.

As a fetus grows, it needs more blood vessels to build new tissues. The endothelium expands and generates more cells and drives the development of adjacent organs. NO facilitates this process with the endothelium at the root of it all. The endothelial cells are directly related to the progression of development and growth; without them, developing babies wouldn’t be able to survive. Without your endothelium, you wouldn’t be here.

Some scientists even think that understanding how endothelial cells communicate during fetal development might help us understand more about health. That’s what’s so exciting about the endothelium—we already know it’s a powerful organ, but there are more and more health secrets being uncovered all the time.

The endothelium is an amazing organ. Endothelial health is linked to all organ and cell health throughout the entire body, and the endothelium is directly related to the function of every cell in the body. Isn’t that incredible?