CBD and Heart Disease

Heart disease is a blanket term for a few different heart complications, each of which is their own disease. 

The heart has many aspects to its functioning, which ensures that a healthy and continuous flow of blood is circulating the body. However, there can be various points of failure which can affect the flow of blood around the body, related to different aspects of heart function. 

Some of them which we will be covering today include:

• Atherosclerosis: the hardening of the arteries
• Coronary Artery Disease: the buildup of plaque in the arteries
• Hypertension: the alteration of blood vessels and heart rate
• (Congestive) Heart Failure: the heart is unable to properly pump blood around the body

CBD is a ubiquitous modulator of many of the biological systems across the body, including the cardiovascular system which comprises the heart, blood vessels and the blood itself. 

Naturally, you may be wondering how exactly CBD impacts heart health and is there any benefit to taking CBD to treat or prevent heart disease? 

Does CBD Affect Heart Rate?

To understand how CBD affects heart rate, we need to take a look at a few aspects of cardiovascular function. 

Heart rate is just one way the heart can change the amount of blood flowing around the body. The others are:

• Stroke Volume - the amount of blood pumped from the left side of the heart per beat 
• Heart rate - the speed at which the heart beats (beats per minute)
• Vasodilation (the dilation of blood vessels)

The total cardiac output (the volume of blood being pumped by the heart per minute) depends on stroke volume x heart rate. Either one of these can change to affect the cardiac output. 

What we would expect  is for CBD to lower heart rate as a function of reducing stress and anxiety. 

Stress is one of the leading reasons for an elevated heart rate, as this puts an extra demand on oxygen consumption throughout the body. This can also lead to an elevated blood pressure. 

I think it is common knowledge now that stress is the biggest killer, and that there is an established link between stress and heart disease/failure. So, there is a case for exploring whether CBD may in fact be used as a preventative measure for heart disease due to its stress reducing capabilities. 

Although we do not have any direct studies exploring CBD and heart disease, we do have evidence that CBD can reduce stress by acting on the nervous system. This may modify how the heart works, which may offset some of the negative effects of stress on the cardiovascular system. 

CBD has been shown to have a calming effect on the nervous system, by encouraging it to transition out of a sympathetic (aroused) state, to a parasympathetic (relaxed) state (*), (*). 

CBD has a powerful anti-anxiety effect, by modifying emotional processing in the brain to help shift the perception of stress, which results in a calming effect throughout the nervous system. 

Interestingly, from the very little evidence we have, CBD has been shown to modify cardiovascular function in a way that we might not expect. 

Surprisingly, CBD increased heart rate modestly, but also reduced stroke volume in a way that kept the cardiac output unchanged (*). However, there was also a reduction in blood pressure, which suggests that despite an increase in heart rate, there was a beneficial effect overall. 

What this shows is that CBD can modify cardiovascular function in a way which can potentially safeguard against stress, by reducing blood pressure. 

Other studies have not found any effect on CBD on heart rate (*), (*) even despite the fact that the endocannabinoids that CBD helps release in the body have been shown to reduce heart rate (*). 

One study found CBD can lower heart rate to a modest (but not meaningful) degree after 60 minutes of ingestion (*). However, this was not a placebo controlled study and was short term in nature. 

There is a thought that the bioavailability of CBD, and the type of CBD impacts whether it may or may not affect heart rate. 

Does CBD lower Cholesterol?

Cholesterol is another risk factor for heart disease, not in and of itself, but what happens to it if there is a lot of inflammation and oxidative stress impacting the blood vessels. Cholesterol can become oxidised (oxLDL), and adhere to the artery walls causing blockages in the arteries (CAD). 

So, it is important that more than anything, the levels of inflammation and oxidative stress are under control, but also that excessive amounts of LDL cholesterol are not produced. 

In many cases statins are used to bring down cholesterol, but unless they are absolutely needed, there are other natural means that can be explored. 

A few examples are red yeast rice extract, berberine and potentially CBD which may help support a healthy metabolism. 

Let’s take a look at the relationship between CBD and cholesterol 

What’s interesting to note is that cholesterol (and some fat) production is actually handled by the endocannabinoid system (ECS) within the liver. 

Western diets (high fat + high sugar) can actually rev up the ECS activity, and cause it to overproduce certain lipids in the liver, one of them being ‘bad’ cholesterol (LDL/VLDL) as well as triglycerides. 

Interestingly, a synthetic cannabinoid drug was developed to target the ECS and its metabolic effects, and was found to produce some astounding results. 20mg/day of Rimonabant significantly improved blood lipid profiles in obese participants, by reducing triglycerides and increasing HDL (good) cholesterol. 

Rimonabant did this by blocking the cannabinoid 1 receptor in the liver, which signals for the pathway that manufactures and packages fats and cholesterol. 

Tragically, Rimonabant came with some pretty nasty side effects and had to be recalled from the market in the early years of 2000 due to severe effects on mood and even suicide. This was due to the fact that Rimonabant not only blocked the CB1 receptor in the liver, but also across the rest of the body and the brain, where it controls mood and emotion. Although it was useful for metabolism, it produced severe depression and anxiety as well. 

CBD shares a similar, but fundamentally different mechanism of action from Rimonabant. As opposed to completely blocking CB1 receptors (antagonist), CBD acts in a more gentle way. 

CBD modifies the shape of the CB1 receptor (negative allosteric modulator) so that not as many endocannabinoids can bind to it to activate the fat producing pathways in the liver. In this way, CBD can modify the process by which fats such as cholesterol are made and transported in the liver. 

CBD also does this selectively, so that there is no effect on the mental side of things, but rather benefits. 

So, CBD can actually be thought of as a buffer to excessive ECS activity that causes obesity, diabetes and heart disease. 

An animal study showed that the ratio of HDL:LDL was improved (that's more ‘good’ cholesterol and less ‘bad’ cholesterol) as well as other fats in the blood (triglycerides) (*). However, this was an animal study, so we need to see this play out in people too before we can get too excited. 

If this does end up being the case, this is another way in which CBD could be beneficial for heart health, and the cardiovascular system in general. 

By improving the HDL:LDL ratio, this would effectively decrease the likelihood of CAD by reducing plaque formation and congesting the arteries. 

One human study with CBD showed that 200mg of isolate per day for 13 weeks did not have any effect on markers of blood lipids in patients with diabetes (1). 

However, another human study found that when just 15mg/day of whole plant CBD was used for a duration of 6 weeks in overweight individuals, that levels of ‘good’ cholesterol significantly increased compared to the control group (2). 

What’s important to note here is that:

• Whole plant CBD is superior to CBD isolate, because it requires a far lower dose as well as being far more effective. In order to get any meaningful effect from isolate, doses of 400-600mg are needed at least. So not surprising to see no effect from the first trial. 
• A higher dose than 15mg/day may in fact have an impact on reducing triglycerides and VLDL. Doses of up to 70mg/day are considered safe according to the FSA. So we will have to see the effects of higher doses of whole plant CBD.
• CBD works to restore balance as an adaptogen, which works uniquely to offset an individual's own level of imbalance. For example, the cholesterol lowering effects may only be applicable for people who have severe imbalance in their levels of cholesterol, not necessarily in healthy humans. Since people in the last study were healthy, you wouldn't expect there to be much of an effect on their metabolic parameters. 

As we’ve mentioned, its not so much that LDL cholesterol is bad, more so when it becomes oxidized. CBD is a potent antioxidant, and it has shown some preliminary benefit in preventing the process of the oxidation of LDL, which is how plaques form and stick to artery walls (3). 

Additionally, oxidative stress also contributes to the hardening of the artery walls, so again the antioxidant capabilities of CBD may help offset its occurrence, although we have yet to see this studied in population studies.

CBD, Inflammation and Heart Disease

Inflammation is a fundamental driver of many aspects of heart disease, from the damaging of artery walls, all the way to damaging of the heart muscle itself. 

CBD is a powerful anti-inflammatory, and suppresses excessive immune activity that is directed towards the bodies own tissues. This means it is well suited to helping preserve the structural and functional capabilities of the cardiovascular system from inflammatory damage. 

Overactive immune cells can damage heart tissue (cardiomyocytes), and lead to heart failure. The cardioprotective roles of CBD are very valuable in light of this (*). 

One trial actually found that CBD reduced arterial stiffness as well as impacting the function of the cells of the vessels themselves (*). 

CBD stimulates the production of nitric oxide (NO) by activating the CB1 receptor amongst human arteries, causing the relaxation of the artery walls. 

Does CBD Lower Blood Pressure?

High blood pressure is an effect of stress, and can itself be a risk factor for developing atherosclerosis. Keeping blood pressure within a healthy range is just one of the ways in which someone can keep themselves protected against the risk of heart disease, as well as considering dietary and lifestyle factors which influence other aspects of heart disease, such as cholesterol oxidation and the flexibility of artery walls. 

CBD has been found to reduce blood pressure in a small clinical trial of around 9 people (*). A larger trial of 26 participants also found that despite CBD only reducing blood pressure for 9 days until the effect diminished, when it was taken under stressful conditions its blood pressure reducing qualities were still apparent (*). 

This is consistent with the role of CBD as an adaptogen, as its effects are most notable when there is significant imbalance (aka elevated blood pressure in response to stress) rather than reducing something that is already within in a range of homeostasis. 

There is a plausible mechanism by which CBD can impact blood pressure, so it is not surprising to have seen its effects in the small trial. 

CBD can plug into the endocannabinoid system, which controls the dilation and contraction of blood vessels with cannabinoid receptors. CBD can technically encourage the dilation of blood vessels in a way which impacts blood pressure, in the direction of lowering it. 

Through its effects on vessel elasticity, CBD may help maintain healthy and flexible arterial walls, as well as reducing the burden on the heart to pump blood through rigid blood vessels.

Does CBD Oil Interact with Blood Pressure Medications?

Because CBD may lower blood pressure through its interaction with the endocannabinoid system, it is technically subject to reactions between blood pressure lowering medications such as statins. 

Because both CBD and blood pressure medication results in the dilation of blood vessels, you would expect there to be an additive effect when both of them are taken within the same day. 

This may result in hypotension, the lowering of blood pressure to a level which may result in dizziness, feeling faint and generally feeling unpleasant. 

The conventional wisdom suggests avoiding taking Blood pressure medication with CBD. Its always worth consulting with your doctor however, for their professional opinion related to individual cases.