February is heart disease month in the US, and if you're not living in a bubble, you hear–over and over again–that nearly half of all Americans are suffering from some type of heart disease, be it high cholesterol, plaque blockages in their arteries, high blood pressure, or an elevated risk of heart attack or store.

That's not you? Awesome. But you should still care about heart disease anyway, and here's why: It happens early, it takes a long time to show up, but what you eat now and how active you are day-to-day, affects your chances of developing some kind of heart disease later. We hear a lot about "gut health," and the microbiome, but it turns out we really should be obsessing over "vascular health" and the endothelial cells that line all of our blood vessels, from the arteries that move blood in and out of the heart and lungs, down to the capillaries that keep our skin flush and clear, our fingers from freezing on a chairlift, and our muscles oxygenated during a tough spin class.

That's the message of Dr. John Cooke, who is Chairman of the Department of Cardiovascular Sciences at Houston Methodist Research Institute, part of the Texas Medical Center, as well as Professor of Cardiovascular Sciences, and Member of the Academic Institute Director of the Center for Cardiovascular Regeneration and a scientific advisor to HumanN, a functional food, and nutritional supplement maker.

Dr. Cooke explains that the endothelial cells should be as much a part of our vernacular as the "microbiome" is for gut health. These endothelial cells form a single cell layer of coating, that lines all the blood vessels of the body and regulates exchanges between the bloodstream and the surrounding tissues. When your blood is healthy the coating acts like Teflon to smoothly carry blood to where it needs to go (the muscles, or skin, say) and when it is unhealthy, because of your diet or another inflammatory event (an injury or disease) the endothelial cells become like velcro, and catch substances that lead to the formation of plaque, blockages, high blood pressure and heart disease.

The connection between gut health and heart health happens in the way your body carries nutrients to your cells -- meaning in your vascular system. Eat plant-based foods and the gut bacteria signals the body to keep that Teflon nice and smooth. Eat junk food and high-animal-fat foods and your blood vessels react by constricting, and the endothelial cells become sticky, catching fat and other cells that lead to plaque -- and in the years to come you'll see stroke risk and heart attack risk go up, along with dementia, cancer and other diseases that result from not eating healthy now.

Dr. Cooke tells us that even if we don't have heart disease, it can be present early on in sneaky ways like fat streaks that show up in the blood vessels of teenagers and young adults who eat a daily diet of junk food, high-fat foods that are derived from animal products, and don't eat enough vegetables, fruit, whole grains, nuts, and seeds. In other words, what we eat in the first half of our life determines how healthy we are in our second half. That does not mean it's ever too late to start to eat healthily, but it does mean that the sooner you switch to a mostly plant-based diet and avoid the junk food, the healthier your endothelial cells, and the rest of you, will be.

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Heart disease is evident in 48 percent of Americans, but chances are even more have it

The fact that heart disease kills Americans at a rate like no other disease, and affects 48 percent of us, and kills 650,000 Americans a year (if you include stroke), does not even make a dent in the consciousness of someone under the age of 30. Or even in some cases, under the age of 40. Yet if doctors who treat cardiovascular disease are to be heeded, more of us are walking around with the early stages of heart disease and we just don't even know it. Even teenagers can have the beginnings of symptoms if you look at what's happening in their blood vessels, their blood lipids and their overall inflammation, and early marker of heart disease. So while half of Americans sounds high it does not even begin to describe the grim reality that two-thirds of Americans likely have some form of early or later stage heart disease or lack of heart health. It's just that many of us don't know it yet.

That's where Dr. Cooke comes in. If it were up to him, Americans would be as obsessed about their vascular health as we are our gut health. In short: What happens in the blood vessels does not stay in the blood vessels. It actually determines everything related to blood flow and oxygen delivery to the cells, from your athletic stamina and endurance to your ability to get oxygen to the brain, and sustain your focus, to the ability of your skin to stay clear and young-looking. It also determines whether or not your body starts to build up plaque in the blood vessels (one of the harbingers of heart disease) or stays clean and smooth, relaxed, and healthy, with your blood flowing in a healthy, low-blood-pressure state.

Blood Vessels are lined with a single cell coating, which acts like Teflon, called the endothelium, but which, if there is inflammation, infection, injury, or a chronic state of unhealthy food coming into the body, starts to act more like velcro, Dr. Cooke explains. That's when things don't flow smoothly and the blood vessels get sticky, essentially, and hold onto the fat flowing through them, creating plaque, and ultimately blockages, that eventually lead to a heart attack or stroke. This doesn't happen quickly but over time, so what shows up in your 40s, 50s, 60s or 70s started way back when you were in high school and grabbed a bag of chips.

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The Beet: If you are healthy, why do you need to care about your blood vessels?

Dr. Cooke: The blood vessels are absolutely critical because they supply the nutrients and oxygen for all the organs in the body. If you were to -- I should say the lining of the blood vessel is also very important. Something I’ve been studying for over 30 years. The lining of the blood vessels called the endothelium. That tissue is just a single cell layer thick. You can’t see it with your naked eye. It’s just a single cell thickness. And it is this film of tissue that is very delicate but it exerts tremendous control over your blood vessels and you need to keep that healthy--that endothelium-- and we can talk about that.

The Beet: There are two extremes of people who pay attention to heart health: Super healthy athletes, and people with disease. How can we talk to everyone else?

Athletes, especially endurance athletes, talk about their VO2 max and how much blood-oxygen you can deliver to your muscles in the middle of a workout. And then there’s obviously those patients who have cardiovascular disease, who have either blockages or high cholesterol. I think we should speak to both, and everyone in the middle. So, we at The Beet espouse a plant-based or mostly plant-based diet or eating heavily plant-based as a way of eating for heart health. How would eating plant-based foods help your blood vessels and that endothelium stay healthy?

Dr. Cooke: Well they do: plant foods help your blood vessels stay healthy. What we are talking about is important for everybody. Even if you are super fit, or you are healthy, or you are not. Because the lining of your blood vessels is the Teflon coating of your blood vessels. It allows the blood to flow smoothly. It causes the relaxation of your blood vessels, so they are wide open. It also prevents things from sticking--it truly is the Teflon coating of the blood vessels. It prevents platelets from sticking, white blood cells from sticking. It prevents blood clots. It prevents inflammation because inflammation starts with the white blood cells adhering to the endothelium, the lining of the blood vessel.

The Beet: So many people talk about inflammation's role in disease

But no one has ever explained to me how inflammation leads to disease. They just say “oh inflammation it’s involved with all major lifestyle diseases” but nobody’s ever explained how.

Dr. Cooke: Blood cells are circulating through our blood vessels all the time and they are surveilling for problems. And if there is a problem, then the endothelium is what signals to them to come to that particular site in the tissue [to start to repair it]. All of our tissues have blood vessels running through them.

The blood vessels are the conduits not only for nutrition and oxygen, but they are also the conduits for white blood cells to get to where they need to go. So, if you have a foreign body or a cut in your skin and you see a little inflammation, it starts off with the endothelium in that area expressing adhesion molecules, meaning it gets sticky. The endothelium becomes more like velcro. Then the white blood cells begin to stick and they can enter the tissue at that site. The endothelium cells present a doormat for white blood cells. They say "Come in here! This is where you need to come because we’ve got something bad going on here. We’ve got a foreign body, pathogens, a problem, you’ve got to help."

The Beet: So, if that like a cut on your finger that’s fine because that inflammation brings all that healing, the platelets, all the good stuff to help your body repair that tissue. But if it’s chronic, what I’ve heard, that’s what leads to high blood pressure and cardiovascular disease.

Dr. Cooke: Yes, absolutely. If you have chronic alterations of the function of this lining of the blood vessel it causes all types of problems. The chronic alterations occur, and you convert it from Teflon to being more like velcro, it causes inflammation, which causes blood clots to form, it can even cause insulin resistance, which is basically diabetes.

The endothelium can actually cause metabolic problems, it can cause diabetes, type II diabetes. The endothelium is absolutely critical for the functioning of our bodies. You mentioned brain function. Absolutely. the function of your skeletal muscle. Your ability to run, jump, play. Mental and physical functioning is dependant on your blood vessels, and this lining of the blood vessels: the endothelium.

We showed quite a few years ago if you feed fatty foods to mice it makes them not able to fun as far on a treadmill. We were putting mice on treadmills in the lab, and they were happily running along on the treadmills. And mice can go pretty far on a treadmill. But if you gave them a high cholesterol diet, then they couldn’t run as far, they couldn’t run as fast and we traced it to an endothelia problem. The endothelium started to make less Nitric Oxide, which is a gas that causes the blood vessels to relax. It is one of the molecules that the endothelium makes that causes blood vessels to relax. It provides that Teflon characteristic of the endothelium.

The Beet: The endothelium makes Nitric Oxide?

I thought Nitric Oxide helped your blood vessels open. But I didn’t know it was actually created by the endothelium.

Dr. Cooke: Yes, it’s created by the endothelium. That’s why this lining, this film of tissue, is so important because it makes a wide-range of factors. It’s a virtual factory, influencing the underlying smooth muscle of the vessel, affecting the circulating blood. One of those factors--and I would say possibly the most important factor--in maintaining health, vascular health is Nitric Oxide. The ability of the endothelium to make Nitric Oxide. relaxes the blood vessel, prevents platelets from sticking. It is very important.

The Beet: That’s amazing. So Nitric Oxide is this miracle gas that keeps everything going along. But I want to bring it back to diet because I think a lot of people feel like they work out and they go to the gym and then afterward they want to go eat protein, and the perception is that they should go eat a steak. Why is that not actually the case?
lI want to connect that back to this picture of food and the relationship between food and heart health.

Dr. Cooke: Well we showed if you feed healthy mice a high cholesterol diet, they can’t run as far. So, your functioning will be adversely affected if your endothelium isn’t treated correctly. And the endothelium likes a plant-based diet. We didn’t show that. Others have shown that a plant-based diet is better for endothelial health than a burger king diet.

The Beet: We’ve done stories on Nitric Oxide. A lot of the same things that are good for your heart are good for that. I’ve heard so many people talk about their gut microbiome. I wish that we could get America to talk about their blood vessel health, their endothelium health. The idea is that there is a connection between gut health and blood vessel health is interesting to me since everyone loves to think about gut health. If you are interested in gut health then the reason is because of what happens in your blood vessels when you eat probiotics, prebiotics, and plant-based foods. Is that a fair way to put this?

Dr. Cooke: Yeah. the microbiome does influence what kind of nutrients get into your circulation. And those nutrients affect your blood vessels. The scary thing is that for people with heart disease–or coronary artery disease that could cause a heart attack or carotid artery disease that could cause a stroke–it's so important that vascular function is healthy in those individuals.

I want people to know how important improving vascular function is for those individuals, but most of those diseases take a long time to show up and they happen over a period of decades, so if you are not taking care of yourself now, you will have coronary disease in the future. In fact, we know this to be true because there have been large studies showing that even young people-like teenagers-start to have evidence of problems in their blood vessels. Early on they get these fatty streaks in their blood vessels. And if you eat a high cholesterol diet you have more of these fatty streaks. And those are the things that grow into plaque that will ultimately obstruct your blood vessel.

The Beet: I am going to wade into a little diet controversy. Let's talk about keto diets.

I happen to think that high-fat diets can be progenitors of these high lipid, high fatty streaks that lead to the blockages that lead to all sorts of heart disease. We are advocates for plant-based eating, or at least eating more plant-based foods. Is it fair to say that a high-fat diet of animal fats like bacon (key to a keto diet)  is not a great idea when talking about heart health?

Dr. Cooke: A high-fat diet, of animal fat, is a terrible idea for your blood vessels. It's going to lead to problems in your heart arteries, your brain arteries. One of the most common causes of dementia is vascular dementia. So Alzheimer's is the number one cause of dementia, but vascular dementia is number two.

With aging, we see a normal decline in your cognitive function, but that can be accelerated by not taking care of your blood vessels. And it can be decelerated, meaning you can avoid cognitive problems f you take care of your blood vessels.

The Beet:  I want to take really good care of my blood vessels after hearing you talk.

Heart disease and caring about your blood vessel health is important at any age. So in your 30s, 40s, 50s is when all this starts to develop. It's much harder to reverse the damage than it is to prevent it, right? So what would you tell somebody right now if they wanted to take good care of their blood vessels?

Dr. Cooke: A lot of what you’ve been telling people, that a plant-based diet is really good for your blood vessels, is great. I, myself, like a Mediterranean diet, because it's appealing and a little bit easier for people and it's good for your blood vessels. There are a lot of plants, fruits, and vegetables in the diet but there's also some fish. You can get your Omega-3 fatty acids from fish or if you want to be purely plant-based you can also get it from flaxseed oil. I like to mix flaxseed oil with balsamic vinegar on my salad. That’s a nice way to get the flaxseed oil that delivers Omega-3s

The Beet: I have nothing against the Meditteranean diet, since it's a really good step toward being your healthiest, compared to the traditional American diet. We’ve talked to doctors who say the same thing as you do, which is that plant-based is best but that the Mediterranean diet is much easier and more sustainable for most people.

Dr. Cooke: Eating more plants is better for us and better for the world. It's better for the environment.

The Beet: Let’s talk about stress for a minute. My stress just went up.

What does it do to your blood vessels when you feel that stress or when you are in that chronic stress mode?

Dr. Cooke: Stress impairs the endothelium. It impairs the relaxation of the blood vessels. You have an increase of circulating factors that cause your vessels to constrict, like adrenaline. So, these things–like noradrenaline–increase the heart rate and the workload on the heart and those are important things when you need to run away from a lion. When you're in danger, you need that physical response. However, if you are sitting in a chair stressing over some work that you need to get done, you are driving your heart rate up, and you are also narrowing your blood vessels, constricting your blood vessels. That impairs the function of the endothelium lining. Stress has been shown to impair the endothelium rather dramatically and rather quickly. You can take a person and put them in a mental arithmetic test, and you will see their vessels constrict. Blood flow in a finger will dramatically shows an immediate decline. So any amount of stress will cause your blood vessels to constrict.

So bottom line: eat a mostly plant-based diet, and stop stressing! When you feel a stressful moment coming on: Breathe!