August 3, 2017

Erectile Dysfunction's Clues About Cardiovascular Health

Interview with Daniel Chong, ND

In over half of all cases of hospitalization for a cardiovascular event, the first symptom is the event itself. So anything we can do to get any early indicator that something is going wrong in the cardiovascular system can have a huge impact. Erectile dysfunction is one such early signal. According to cardiovascular health expert Daniel Chong, ND, identifying sexual dysfunction is essential for improving cardiovascular outcomes. 

Approximate listening time: 30 minutes

About the Interview

It may seem counterintuitive to interview a cardiologist, and not a urologist, on the topic of erectile dysfunction (ED). But we now know that ED is a result of endothelial cell dysfunction and ED can be an early warning sign of systemic atherosclerosis. Looking at ED from a cardiovascular perspective is essential.

That’s why we invited cardiovascular expert Daniel Chong, ND, to talk to us about ED’s connection to heart health. In this interview, Natural Medicine Journal’s editor-in-chief, Tina Kaczor, ND, FABNO, asks Chong about the complex interplay between vascular function and sexual function.

According to Chong, cardiovascular disease always has some degree of contribution—potentially a major one—in ED. That’s in part because blood flow is the key facet to obtaining a full erection. Cardiovascular dysfunction, including plaque in the arteries that regulate that blood flow, can therefore have an impact on ED. Even before plaque development becomes a problem, endothelial dysfunction in the inside walls of the arteries can play a role in erectile function.

In this enlightening interview, Chong explains the different issues that can contribute to ED, including anatomical, physiological, and psychological problems. It’s an important listen for any practitioner who sees men, since beyond being a problem in and of itself ED can be an early signal of other serious health concerns.

About the Expert

Daniel Chong

Daniel Chong, ND is a licensed naturopathic physician, practicing in Portland, OR since 2000. Chong's focus is on healthy aging of the brain and body, as well as risk assessment, prevention and drug-free treatment strategies for cardiovascular disease and diabetes. He also maintains a virtual practice via the internet for group and individual coaching in cardiovascular disease prevention.

In addition to his degree in naturopathic medicine, Chong has completed certificate training in Cardio-Metabolic medicine with Drs. Mark Houston and Joel Kahn, at The Academy of Anti-Aging Medicine. He is also a contributing editor in cardiology for the Natural Medicine Journal and a clinical consultant for Boston Heart Diagnostics Lab.

You can learn more about him at


Tina Kaczor, ND, FABNO: Hello. I’m Tina Kaczor for the Natural Medicine Journal. Today, we’re going to be talking about erectile dysfunction and cardiovascular disease with Dr Daniel Chong. Dr Chong is a naturopathic physician with a private practice in Portland, Oregon for the past 17 years. He specializes in what he likes to call "vascular wellness optimization." He’s also the founder of the web-based consulting company, the Healthy Heart Project which offers a number of educational and direct consulting options for both the general public as well as healthcare practitioners on how best to assess and reduce risk for cardiovascular disease. Dr Chong also lectures and serves as a clinical consultant for Boston Heart Diagnostics Lab.

Thanks so much for joining me today, Dr Chong.

Daniel Chong, ND: You're welcome, Tina. Good to be here.

Kaczor: As I mentioned, our topic today is erectile dysfunction. At first, it may seem odd to our listeners that I’m talking to a cardiology expert and not a urologist or men’s health expert but we now know that erectile dysfunction is a result of dysfunction of endothelial cells and in fact, this can be an early warning sign of systemic atherosclerosis. Dr Chong, can you start us out with a brief overview of how erectile dysfunction and cardiovascular disease are related?

Chong: Sure. I can do my best there. There’s definitely going to be different circumstances that can contribute to erectile dysfunction. Some of which may not be actually anatomical, so to speak, or physiological from the cardiovascular perspective but I would say the majority is at least indirectly affected because even if we’re talking, for example, about a psychological contributor which we may touch on later, if somebody has dysfunctional arteries down there in the penis, they’re going to be more vulnerable to effects from psychological aspects than they would be otherwise. In other words, a young teenager may get stressed out in an early sexual experience but that’s not going to affect function as much as it could a 50-year-old man.

Anyways, in general, we could just say that cardiovascular disease is going to have some degree of contribution and potentially major. Obviously, blood flow is the key facet to obtaining a full erection and certain arteries are going to be more vulnerable to impacts from the development of cardiovascular disease but even so, the arteries in the penis may or may not actually have plaque in them but they can still dysfunction. Typically, we know, and we’re going to talk about this later, in cardiovascular disease, the preceding step prior to actual anatomical change or plaque development is endothelial dysfunction or dysfunction in the inside wall of the arteries and even that going on without any actual plaque having developed yet can affect erectile function and not to be noticeable by the person.

All in all, I guess you could say they’re intimately intertwined because you have to have good blood flow. It may or may not have plaque. Plaque may or may not be actually playing a role yet but it will in some cases and cause really significant dysfunction, but even minor dysfunction is going to be at least the partial result of the arteries starting to misbehave for various reasons that hopefully we’ll touch on.

Kaczor: Yeah. I actually came across some mention of erectile dysfunction in that whole idea of plaque formation. One author said that it could signify in some patients, or at least it should be followed up to see if it signifies subclinical atherosclerosis.

Chong: Correct.

Kaczor: Yeah. Atherosclerosis being pretty much asymptomatic in people until there’s larger consequences. On that note-

Chong: Right. Yeah. Sorry to cut you off. Sadly, it’s been shown that in over 50% of cases of hospitalization for a cardiovascular event, the first symptom is the event and that’s over half of all of them, so anything we can do to get any early indicator of something in this, so to speak, before, for example, erectile dysfunction, is hugely important for us because we are not doing a very good job at least conventionally in identifying early on what’s going on with people.

Kaczor: Yeah. I look forward later in this discussion to talk to you about how to assess it, to find early markers besides just the symptom of erectile dysfunction but let’s start with the larger picture in conventionally recognized erectile dysfunction and cardiovascular disease risk factors. Can you talk a little bit about like when we’re, as clinicians, who walk into our office, who we should suspect it in or at least engage in the conversation because many patients won’t bring it up themselves unless they're directly asked?

Dr Chong: Yeah, absolutely, so, certainly age. The older a man gets, the more potential there's going to be for all kinds of different changes going on physiologically. Some people are well aware of testosterone production, how crucial that is and that certainly begins to change as a man ages. But certainly, very standard, interestingly enough, it’s the same standard risk factors you might consider for cardiovascular disease in general in terms of high blood pressure, diabetes, certainly, smoking.

Conventionally, you're going to see high cholesterol as a stated contributor but we can certainly talk in more detail about that because I know that some people out there in the functional medicine world, naturopathic world, et cetera, consider high cholesterol as a past tense risk factor for cardiovascular disease which it really is and it’s just more complicated than that. Obesity, lifestyle factors in terms of exercise and then certainly, psychological factors, depression and anxiety, et cetera are all going to be key things.

I also want to make a just brief mention even though this is kind of a topic in and of itself, when we talk about erectile dysfunction, obviously, we’re talking about men but it should be very clearly stated that the same potential processes are going on in women as they age. Women with difficulty with sexual activity or orgasm, et cetera, may in fact be having their own version of “erectile dysfunction” with the clitoris as essentially an analogous structure in a woman and all of these blood flow issues can occur in women as well. It’s important to really kind of make mention to that. I say men, I keep saying men, as men age, blah, blah, blah, but it really should be looked at as both sides of the coin, so to speak.

Kaczor: That’s actually an important point. Thank you for mentioning that.

Chong: Sure.

Kaczor: I want to do a follow-up on that cholesterol thing that you just mentioned because I think that that’s kind of top of mind. I think it’s important to give voice to any new data on looking at cholesterol because I'm with you on it being much more complex and it’s more complex than I understand. I'm happy for you to kind of flesh it out for us.

Chong: Yeah. I mean, I guess anybody that says that cholesterol has nothing to do with cardiovascular disease is not really thinking about the fine details of the situation. You can't have a plaque form without cholesterol and lipoprotein particles being involved because they are what are the sort of primary components to the development of the plaque.

What I don’t agree with conventionally is the idea that high cholesterol, in and of itself, is just going to definitively contribute to cardiovascular disease because obviously, there are many people out there who have relatively “high cholesterol” who don’t get cardiovascular disease. There's certainly something else going on that’s playing a role as to whether or not high cholesterol is going to lead to that issue in some people versus others.

Long story short, I consider cholesterol and related markers to be secondary factors. They are absolutely involved but they are not … There's going to be other things that help sort of determine the likelihood or lack thereof of the high cholesterol sort of turning into cardiovascular disease. That’s a really fun discussion in and of itself. It could be another hour or so by itself but hopefully, that kind of answers your question, at least preliminarily.

Kaczor: Well, it brings up another question which is-

Chong: Certainly, keep going with that. Yeah.

Kaczor: Yeah. If cholesterol is considered a secondary factor, and I see what you're saying, cholesterol is not … needs to be present but can't be causative because there's not a cause and effect 100% of the time.

Chong: Correct.

Kaczor: If it’s secondary, what are you looking at as primary?

Chong: Well, to me, the absolute most important thing that’s going to contribute to the potential or lack thereof of eventual cardiovascular disease development or i.e. plaque, development is the health and vitality of the walls of the artery and how well they're functioning. In other words, the healthier, more nutritionally replete the walls of the arteries are themselves and the better they're being sort of manufactured in the first place by the body, are going to be the primary factor that leads to vulnerability or not.

If you imagine like … I would like to use analogies. On a coastline, you may have, let’s say, in Hawaii versus somewhere else on the mainland. Hawaii is made up of volcanic rock which is, tends to be a little bit more brittle and it can sort of erode more easily. If you have waves crashing into the wall, into a wall of rock in Hawaii, it may erode more quickly. Then, an analogous wall somewhere else in the world that’s made up of a different, harder, more resilient material, the waves are still crashing into them with the same potential force but one’s going to erode more quickly than another.

If we then relate that to the vascular system, somebody who has poor nutrition and tons of inflammation, oxidative stress, et cetera, and especially long-term poor nutrition, they're not going to be able … especially if we’re talking about collagen production, they're not going to be able to manufacture the sort of strong, resilient vascular walls that they should which will inevitably be, if they are stronger, will inevitably be more resistant and resilient to the impact of the turbulence of the flow of blood.

There are certainly other things that are going to impact that as well especially the turbulence itself and the viscosity of the blood. That’s going to make for essentially like stronger waves crashing in which obviously, the stronger the waves is crashing into the area, the more potential there is for erosion as well. To me, long story short, the primary situation that’s going to lead to the potential development of plaque is a combination of two primary factors. That’s the vulnerability of the wall of the artery and the stress that is being placed on the wall of artery.

Kaczor: By-

Chong: If you look at every single risk factor we know of, they are impacting one or both of those factors.

Kaczor: Okay. When you say stress, you mean mechanical forces, as well as chemical?

Chong: Chemical. Absolutely.

Kaczor: As in oxidative stress?

Chong: Correct. That would be one of them. I mean, even environmental toxins, different types of infectious organisms and certainly mechanical stress as well or what we call blood viscosity which is impacted by a variety of factors. Primarily, probably the main ones for blood viscosity would be hydration and like even iron levels or high sort of … basically, concentrated solid substances in the blood and then also, cloudiness of the blood, how high is fibrinogen levels and things like that are going to impact the viscosity of the blood. Then, the classic risk factor of high blood pressure is going to be too, more or less, stress on the wall of artery.

Kaczor: Let’s-

Chong: Sorry. One other thing. I mean, one of the ways that high cholesterol may be contributing to things is it’s known that the higher the cholesterol is, the stronger the impact on the vascular wall is. It actually causes … High cholesterol itself can contribute to endothelial dysfunction or stress on the function of the wall of the artery.

Kaczor: Doing mechanical forces, you're saying, to the viscosity of the blood.

Chong: Right, and more technical reasons, like it literally messes with certain aspects of how the wall, the endothelium is supposed to be functioning. It’s not just that it gets into and becomes part of the plaque. The higher your cholesterol goes, the potentially worse the endothelial function initially.

Kaczor: Okay. Let’s switch gears a little bit. If we’re talking about endothelial dysfunction as the commonality between erectile dysfunction, atherosclerosis, cardiovascular disease, it’s all about a healthy endothelium.

Chong: Right.

Kaczor: It’s interesting, in that same paper I mentioned before, I came across a term that I had not seen before. It was the endothelium as a single organ which I thought was a really interesting concept like, “Oh,” thinking, “I'm sure it’s different, in different tissues,” but just the idea of overall health of it being a singular thing was interesting to me.

Chong: Right. People look at the blood vessel as like these tubes that are just allowing for the passage of blood flow. There's so much going on at the wall of the artery physiologically. It is absolutely an entire organ.

Kaczor: Let me ask you this. As far, for us as clinicians, what are either biomarkers or assessment tools, how do we gauge endothelial function in a patient?

Chong: Well, technically, when we’re specifically talking about endothelial function, there's only a few ways to directly assess that. Clinically, they're going to involve some way, shape, or form of actually testing, in-office, the function of the arteries themselves. There's a general … There's a few … There's basically two main machines that I'm aware of. One is called an EndoPAT and one is called the EndoTherm that are designed to directly assess endothelial function.

The way they basically work is they … You have your fingers in some type of device that’s monitoring either blood flow or temperature at the fingertips. Then, you basically occlude the artery and the arm like you would with the blood pressure cuff. You have to do that for about 5 minutes which is not enjoyable for the patient because, as you can imagine, it isn’t feel very good to have your blood occluded for 5 minutes. Then, prior to doing that though, you're doing a general assessment on blood flow and temperature of the fingers. Then, you occlude the blood flow and then you let it out all at once.

When the blood comes, as you might imagine, rushing back into the extremities in the fingers, you should get some degree of expansion of the arteries. Normal function would lead to the arteries, as the blood really rushes in there, would lead to the arteries expanding to a certain extent. People that have endothelial dysfunction, their blood vessels will not expand appropriately. The machines are designed to sort of read that, sort of the tip, where your tips of your fingers are sitting, the machines is detecting, is there a significant enough change in temperature and or blood flow.

There's also something called arterial pulse velocity which basically, there's a smaller device called an iHeart like an iPod but it’s iHeart. I'm not connected to any of these companies or anything like that but that is a newer device that’s being developed that checks sort of indirectly the same thing. It looks kind of like a pulse oximeter but it’s actually detecting arterial pulse wave velocity and literally how quickly a pulse rate is moving down the arterial tree.

If you might imagine, the sort of left compliant and arterial, an artery is, the quicker the pulse rate is going to move down it. That’s generated by heart, a heartbeat. Those are the only ways that I'm aware that are … Those are the only things that I'm aware that are being used in-office to directly assess endothelial function. There is a lab test that can be measured with people called ADMA. It stands for asymmetric dimethylarginine. That is considered a surrogate or indirect assessment of endothelial function. The higher the ADMA is, the higher the potential for endothelial dysfunction because it’s a direct sort of inhibitor of nitric oxide production.

Kaczor: All right. Well, that leads us into our next little piece, doesn’t it? Nitric oxide production being integral to the whole relaxation of the smooth muscle and the endothelium to allow for blood flow whether we’re talking about the fingertips or the penis. Can you talk a little bit about nitric oxide? Maybe briefly mention how an assessment can be made, the ADMA being one of the means of assessing that as far as the blood test and anything else that might be accessible to a general physician or clinician that might be seeing these patients.

Chong: Well, I mean, endothelial function is, to me, the ideal way to get an assessment of that because I'm a big proponent of the idea that we want to check end of point factors as often as we can. Classic example of this is looking at the different impacts of certain dietary changes on cholesterol markers and making conclusions about whether or not that is good for the vascular system or not, certain changes like HDL going up, for example, after the implementation of a certain diet did not guarantee by any stretch of the imagination that you're having a positive effect on the vascular system so I like to use endpoint markers or end, sort of, functional markers as much as possible so far and away still, the best way to me to assess nitric oxide levels is via those endothelial function tests that we mentioned already.

Other ways to sort of try to get an assessment of it, the only other way that I’m really aware of is if you've seen … You've been to enough conferences, I know. You’ve probably seen this company that has this little saliva test that you can use to check basically nitrate levels in the saliva. That’s going to be … Nitrate is a crucial factor, nitric oxide production as well, so some people are using these little saliva tests to check what a person’s typical nitrate intake is and then recommending dietary or supplement interventions based on that. Those are really the only ways that I’m aware of to sort of really truly get an assessment on that other than, obviously, history and talking to a person, seeing how well things are working, so to speak.

Kaczor: Can I ask you a question? I don’t mean to put you on the spot and I do not know the company that’s offering nitrate levels in saliva but is this something that’s been validated or is it with any rigor or is this one of those early adoption things that happen?

Chong: Right. You're asking me if something has been validated with scientific tests or research? Can you restate?

Kaczor: Or at least … Yeah.

Chong: You do that with everything which is great. That’s why I like you so much but I don't know for sure. This is … In all honesty, I haven’t really looked too deeply into that method of assessment with people, so I wouldn’t be able to say with any certainty at all. I know that they’re quite widely used and it’s not a very complicated, technically complicated test so I think it’s pretty straightforward. I do recall seeing literature being made available by these companies but I have not looked that in-depth at that at this point.

Kaczor: Well, I appreciate your honesty. When you're on the cutting edge, early adoption of new technologies is part of our … We get to do that. We get to be right there doing, instituting things but it’s important, I think, for us all to go at a pace that has some, at least reproducibility, if not rigor.

Chong: Absolutely. The other thing that I would say to add to that is like using different angles of assessment is also crucial, not just relying on one piece of information whether it be cholesterol. That’s why the classic conventional mistake is like, “Okay, we’re going to check and see if you have a high risk for cardiovascular disease. Let’s check your lipid panel. There’s so much more beyond that that can be done to assess and evaluate people and get a much clearer picture. That’s a classic idea, just sort of not settling on one thing, not just using the newest thing, whatever it is. Use as many tools as you can within reason to get the clearest picture.

Kaczor: Yeah. I want to continue on the molecular biology of this and specifically, we have just a few minutes left, really talk about-

Chong: Time flies when you're talking about erectile dysfunction.

Kaczor: What’s that?

Chong: I said time flies when you're talking about erectile dysfunction.

Kaczor: Well, oxidative stress, being something that you mentioned and it’s just something that we’re … That inflammation is kind of always at the forefront of anyone who’s doing integrative medicine or optimal wellness or however you want to term it. I guess my thought is this. In a concise way, can you tell me if you use any actual blood markers that are widely available and what are some of your favorite ways of, kind of across the board, addressing oxidative stress issues, which even beyond erectile dysfunction, it becomes part and parcel with that but it’s also just part of life and part of being alive, is creating oxidation?

Chong: Right. In the realm of assessment, especially if we were going to so far as to separate out inflammation in oxidative stress because obviously, they aren’t exactly the same thing, when we’re talking inflammation, the primary markers that I’m measuring with people certainly are high sensitivity CRP as our sort of general global marker of inflammation or lack thereof. When we’re talking about the vascular system, I’m also typically going to be checking something called Lp-PLA2 or what’s also known as the PLAC test. That is more specifically an inflammation marker for the vascular system so it’s going to actually reveal immunoactivity and inflammation going on in the wall of the artery whereas a high CRP is not going to be able to definitively determine that or not. MPO or myeloperoxidase is a later stage, nonspecific but frequently correlated marker for late stage vascular inflammation for a vulnerable vascular system.

In the realm of oxidative stress, the 2 primary markers that I might look at is actually … number 1 is actually oxidized LDL so it’s pretty hard to have moderately elevated LDL levels and a high amount of oxidative stress and not see a relatively increased level of oxidized LDL in the bloodstream. That is sort of a good, what you'd call extracellular oxidative stress marker, but we can also get intracellular oxidative stress for different reasons.

For that, you can also check something called 8-oxoguanine which is an actual, actually a urinary test. Not too many labs run that. I’m not sure if we’re supposed to name names here but that is an … If you just Google 8-oxoguanine test or something like that, you can probably find the labs that run that but that’s going to give you more of an assessment of intracellular oxidative stress. Then, beyond that, you can, in all honesty, get a pretty good idea whether or not somebody is going to be a candidate for high oxidative stress just by talking to them and looking at them and that type of thing as well.

Kaczor: Yeah. A lot of those other markers for cardiovascular disease like obesity, even the aging process, certainly smoking, all-

Chong: Right. Absolutely.

Kaczor: Obviously, we would take into account for oxidation. Can you let me know or let the listeners know your top three? Someone looks at you and they’re like, “Listen. I do everything right. I exercise. I eat well. My BMI is normal. I don’t drink. I don’t smoke. What are the three supplements you …” You only get to see them once. They’re going to leave your office.

Chong: These people are eating well, you said, in my opinion?

Kaczor: Okay. That brings up the point. What would that look like in your opinion?

Chong: No, no. I’m sorry. I’m just-

Kaczor: We only have 2 minutes left but what would be an ideal guy in your opinion and then-

Chong: No, no, no, no, no. I’m sorry. I was just clarifying the question. If these people are already eating well like they’re eating lots of fruits and vegetables, et cetera and I’m just talking about supplements, the 3 main ones I’m going to recommend are going to be vitamin C, magnesium, and then probably some type of concentrated plant-based antioxidant. As a naturopath, herbal medicine trained, I have an affinity to hawthorn but also, I frequently recommend hibiscus tea to people.

Kaczor: Nice. Hibiscus being, you're also from Hawaii so that’s-

Chong: Good point. You could certainly go beyond that and complement it with things like arginine, citrulline, and then there are a number of nitric oxide precursor type of products that are high in dietary nitrates.

Kaczor: Well, Dan, I really appreciate this. I feel like we could have a whole part 2 where we go into the therapeutics and more details into all of this but I think the listeners have gotten good overview today and I really do appreciate the time you've taken and your expertise, and best of luck with your Healthy Heart Project.

Chong: Thank you, Tina. It was good to talk to you and happy to help as I can.

Kaczor: All right. Take care.

Chong: All right.

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