Hawthorn: The three-in-one natural remedy for high blood pressure

James Meschino DC, MS, ROHP

High blood pressure affects approximately twenty-five percent of the adult population in developed countries like the United States and Canada. In up to 75% of these cases, hypertension manifests in a mild form which is highly sensitive to nutrition, supplementation and lifestyle practices.

Hawthorn has been prescribed by European doctors for years to treat various heart conditions including hypertension, ischemic heart disease (angina), and congestive heart failure. Hawthorn’s cardiovascular benefits are primarily due to the unique complement of flavonoid compounds found in its leaves, berries and blossoms, particularly anthocyanidins and proanthocyanidins. These active constituents have been shown to act in three ways to help reduce high blood pressure, and clinical studies have proven that supplementation with hawthorn extract can be a safe, natural method to treat mild to moderate hypertension.

As mentioned, hawthorn has been shown to provide three distinctive physiological effects, each of which contribute to its anti-hypertensive properties. These include:

1. ACE – inhibitor
2. Calcium channel blocker
3. Nitric oxide release (vasodilator)

ACE-Inhibitors
ACE-inhibitors are agents that block the conversion of angiotensin I to angiotensin II, thereby reducing high blood pressure.

Under normal conditions, the angiotensin system is activated in response to hypotension, decreased sodium concentration in the distal tubule, decreased blood volume and/or renal sympathetic nerve stimulation. In response, the kidneys release renin which cleaves the liver-derived angiotensinogen into angiotensin I. Angiotensin I is then converted to angiotensin II via the angiotensin converting enzymes (ACE) in the pulmonary circulation, as well as in the endothelium of blood vessels in many parts of the body. The system, in general, aims to increase blood pressure

How Does Angiotensin II Increase Blood Pressure
Angiotensin II is a potent vasoconstrictor, which constricts arteries and veins and increases blood pressure. Angiotensin II also has prothrombotic potential through adhesion and aggregation of platelets and production of PAI-1 and PAI-2 (plasminogen activator inhibitor) – which decreases fibrinolysis. Angiotensin II also potentiates the release of norepinephrine by direct action on postganglionic sympathetic fibers. Angiotensin II also increases sodium resorption in the proximal tubules of the kidney.

All of these effects increase blood pressure and can increase risk of thrombosis and hypertension in a state of dysregulation. With ACE inhibitor use, the effects of angiotensin II are prevented, leading to decreased blood pressure (ACE-Inhibitors inhibit the enzyme that converts Angiotensin I into Angiotensin II) and decreased platelet adhesion.

ACE-inhibitors are also the drug of choice in the management of diabetes to retard progress of diabetic nephropathy. Although many prescription drugs are prescribed for their ACE-inhibitor properties, hawthorn extract has been shown to lower blood pressure by acting as a natural ACE-inhibitor, in cases of mild to moderate hypertension.

Calcium-Channel Blockers
Calcium channel blockers work by blocking voltage-gated calcium channels (VGCCs) in muscle cells of the heart and blood vessels. This prevents calcium levels from increasing as much in the cells when stimulated, leading to less muscle contraction.       In the heart, this decreases cardiac contractility (systolic pressure).  In blood vessels, a decrease in calcium results in less contraction of the vascular smooth muscle and therefore an increase vasodilation (diastolic pressure). Vasodilation decreases total peripheral resistance, while a decrease in cardiac contractility decreases cardiac output.      Thus, these effects lower diastolic and systolic blood pressure. Although many anti-hypertensive prescription drugs act as calcium channel blockers, studies have shown that the active constituents in hawthorn can help to lower mild to moderate hypertension via their natural calcium channel blocker properties.

Nitric Oxide Release (Vasodilation)
Under normal conditions, the endothelial cells that line our blood vessels secrete nitric oxide, which dilates the vessel in accordance with the oxygen required by the tissues supplied by the vessel. In atherosclerosis, and under certain other conditions (cigarette smoking, high cholesterol, lack of antioxidant or folic acid status), individuals experience endothelial dysfunction, whereby the arterioles remain in a relative state of vasoconstriction. In turn, this reduces blood flow to the tissues supplied by these vessels, which can exacerbate angina, ischemic heart disease and hypertension.

In addition to dietary modification, exercise and medication use (e.g. nitroglycerine) to modify endothelial dysfunction, hawthorn extract has shown an ability to increase release of nitric oxide and promote vasodilation. This is another way in which hawthorn extract may reduce high blood pressure and promote improved circulation to the heart muscle.

In addition, hawthorn extract has a proven positive inotropic effect on the heart muscle (similar to coenzyme Q10), enabling the heart muscle to generate more ATP energy for myocardial contraction. This is why it remains a key intervention of choice in the management of congestive heart failure among European physicians, who have used hawthorn extensively over the years for various cardiovascular conditions, including congestive heart failure and the management of hypertension.

Hawthorn Dosage in Hypertension
In cases of mild to moderate high blood pressure you may consider recommending a daily dosage of 150-300 mg per day of hawthorn extract (standardized to contain 3-5% flavonoid content). I usually recommend a combination supplement product containing coenzyme Q10 and hawthorn, as both CoQ10 and hawthorn have blood pressure-lowering effects, improve endothelial function and have a positive inotropic effect on the heart muscle. Each capsule of the combination supplement I recommend contains:

1. Co Q10 – 30 mg
2. Hawthorn Extract – 37.5 mg (std to 5% flavonoids)
3. Quercetin – 50 mg (quercetin is associated with lower cardiovascular risk in some studies)

I recommend that the patient take 2 capsules, 2 to 4 times per day, depending on the degree of hypertension, co-morbidity issues (overweight, high cholesterol, etc.) and other factors (fitness level, smoking, etc.), as well as monitoring their response. I often start with lower dosage (2 capsules, twice per day) and increase the dosage weekly if necessary, depending on the patient’s blood pressure response to treatment.

Note that the patient can take a supplement combination of this type in association with any other anti-hypertensive drug prescribed by their physician. However, hawthorn is not safe to take in conjunction with digitalis or digoxin, which are prescribed in some cases of congestive heart failure and arrhythmias.

You should also make the patient aware of other lifestyle practices that help to reduce high blood pressure:

• Weight loss (if over weight)
• Eliminate or reduce alcohol consumption
• Reduce sodium intake
• Calcium/magnesium supplementation (1200-1500/250-600 mg respectively)
• Endurance Exercise (4-6 times per week for at least 20-30 minutes)
• Stress reduction (biofeedback, yoga, progressive relaxation etc)

Summary
Scientific and clinical investigations have shown that active constituents in hawthorn extract can reduce high blood pressure via their influence on the angiotensin system, by acting as calcium channel blockers and by improving endothelial function. When taken with coenzyme Q10, and in conjunction with other anti-hypertensive lifestyle measures, hawthorn supplementation is a key element in the natural management of mild to moderate high blood pressure. In North America, hawthorn is often overlooked in this regard. As such, natural health practitioners should bring this information to the attention of their hypertensive patients for the purpose of enhancing the management of their condition, and reducing their dependency on other medications which may carry a greater risk of untoward side effects.

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