Hawthorn (Crataegus oxyacantha) can stimulate the heart and arterial circulation and is considered by herbalists to be a potent cardiac tonic. Hawthorn promotes healthy blood pressure and cholesterol levels by relaxing blood vessels, increasing metabolism in the heart muscle and improving blood supply. This herb is also used to treat insomnia, nervousness, poor digestion, and obesity.

Hawthorn is a thorny shrub that belongs to the rose family. Its flowers bloom in May and appear as small white, red or pink clusters. Small berries, called haws, form after the flowers are gone. The berries are usually red when ripe, but they may also be black. Hawthorn leaves are shiny and grow in a variety of shapes and sizes.

Hawthorn side effects

Herbs contain components that may result in side effects and interact with other herbs, supplements or medicines. For these reasons, herbs should be taken with care, under the supervision of a health care professional.

Hawthorn is considered a safe herb. Side effects are rare, but may include headache, nausea and palpitations. A recent review of 29 clinical studies with more than 5,500 patients found that hawthorn was safe when used in doses that ranged from 160 to 1800 mg daily and from 3 to 24 weeks in duration.

If pregnant or breastfeeding, do not use hawthorn.

Possible hawthorn drug interactions

If taking prescription or non-prescription drugs talk to a health care professional before taking herbal supplements. If being treated with any of the following medications, hawthorn should not be taken without first talking to a health care professional. Drugs that hawthorn can interact with include the following:

Beta-blockers: These drugs are used to lower blood pressure and dilate blood vessels. Hawthorn can boost the effects of these drugs.

Calcium channel blockers: These drugs are used to treat high blood pressure and angina by dilating blood vessels. Hawthorn can enhance the effects of these drugs.

Digoxin: Hawthorn may enhance the effects of digoxin, a drug used to treat irregular heart rhythms.
Phenylephrine: Hawthorn has been found to reduced the activity of phenylephrine, a drug that constricts blood vessels and that is commonly included in nasal decongestant products.

Hawthorn dosage

About 160 to 900 mg of hawthorn leaf and flower extract is suggested to be taken daily for six weeks.

Hawthorn should not be given to children.

Hawthorn can be purchased in non-standardized and standardized capsules and liquid extracts, and as tinctures and solid extracts. A tea can also be brewed from dried hawthorn leaves, flowers and berries.

How does hawthorn work?

Hawthorn contains antioxidants, including oligomeric procyandins and quercetin. Antioxidants neutralize free radicals – reactive compounds in the body that can damage cell membranes, DNA, and in extreme circumstances initiate cell death. Free radicals are now known to contribute to the aging process as well as the development of a number of diseases including cancer and heart disease.

Hawthorn can dilate arteries and improve coronary blood flow, thus reducing blood pressure. It can widen blood vessels, especially the coronary arteries. Some of the flavonoids in Hawthorn can help in preventing the narrowing of blood vessels. Hawthorn also acts as a mild diuretic that reduces blood volume. Many patients that take hawthorn experience a drop in blood pressure of 10 to 15 points over 8 weeks. Once blood pressure has decreased, it may be possible to reduce the dosage or to stop taking hawthorn altogether.

Hawthorn constituents

Hawthorn contains many substances that may benefit the heart. These antioxidant flavonoids that include OPCs may help dilate blood vessels, improve blood flow and protect the blood vessels from damage.

The berries, leaves and flowers of the hawthorn plant have been used for medicinal purposes. Most modern preparations use the leaves and flowers, which are believed to contain more of the flavonoids than the berries.

Hawthorn is considered a safe herb. Side effects are rare, but may include headache, nausea, and palpitations (a feeling of a racing heart). A recent review of 29 clinical studies with more than 5,500 patients found that hawthorn was safe when used in recommended dosages. Doses found to be safe were from 160 – 1,800 mg daily and from 3 – 24 weeks in length.

Heart disease is a serious condition. Do not self-treat heart conditions without telling your doctor. You should use hawthorn only under your doctor’s supervision.

If you are pregnant or breastfeeding, do not use hawthorn.

It is important to note any changes you feel while you are taking hawthorn. People experiencing more pain, more angina attacks, or more exhaustion while walking or exercising should stop taking hawthorn and seek emergency medical attention. Even if you don’t experience any of these symptoms, see your health care provider if your condition hasn’t improved after 6 weeks of hawthorn treatment. Your progress should always be monitored by your doctor.

Medicinal uses of hawthorn

Hawthorn and blood pressure

Hawthorn has been used for many centuries as a remedy for cardiovascular disease. Traditionally, the berries were used to treat health problems that included high blood pressure, irregular heartbeat, chest pain, hardening of the arteries and heart failure. Today, the leaves and flowers are used medicinally, and there is scientific evidence that hawthorn can treat mild-to-moderate heart failure.

In one study, a hawthorn extract was found to be effective in treating hypertension in patients with type 2 diabetes that were also taking their prescribed medicines. Participants took 1,200 mg hawthorn extract daily or placebo for 16 weeks. Patients taking hawthorn had lower blood pressures than those taking the placebo.

You should talk with your doctor before taking hawthorn for high blood pressure.

Heart failure

A number of studies have concluded that hawthorn can improve heart function. Clinical studies have reported that hawthorn significantly improved symptoms of heart disease such as shortness of breath and fatigue. One study demonstrated that hawthorn extract (900 mg/day) taken for 2 months was as effective as low doses of Captopril (a prescription heart drug) in improving heart function.

Chest pain (Angina)

Some preliminary scientific evidence suggests that hawthorn may help combat chest pain (angina), which is caused by a reduction in blood flow to the heart. In one preliminary study, 60 patients with angina were given either 180 mg/day of hawthorn berry-leaf-flower extract or placebo for 3 weeks. Those who received hawthorn experienced improved blood flow to the heart and were also able to exercise for longer periods of time without experiencing chest pain.

The information provided in this article is for educational purposes only and should not be used for the diagnosis or treatment of any medical condition.

Niacin, also known as vitamin B3 or nicotinic acid, is a colorless, water-soluble organic compound with the formula C5H4NCO2H. This vitamin is essential for various biochemical processes to take place in the body, one being the metabolism of fat. Niacin may also lower blood pressure, particularly at higher doses administered over a longer period of time. Additionally, there is another common form of B3 called niacinamide.

See also: Herbs for High Blood Pressure

How Does Niacin Work?

Niacin and the lowering of blood pressure

Immediate-release niacin may lower blood pressure because of its vasodilatory effects. Some clinical studies have found that niacin may lower BP when administered over an extended period of time. Niacin activates the G protein-coupled GPR109A receptors on cells such as adipocytes, which may impact on lipid metabolism. These receptors are also found on epidermal Langerhans cells in the skin, and generate prostaglandins such as PGD2, which in turn, stimulate PGD2 type 1 (PD1) receptors on vascular smooth-muscle cells in dermal arterioles, resulting in vasodilatation and flushing. GPR109A activation on Langerhans cells may also produce PGE2 and possibly other mediators that could potentially influence vascular tone and thus may also contribute to a lowering of blood pressure. Additionally, niacin could potentially activate its receptor on other cell types (including other components of the cardiovascular system) that could lead to haemodynamic changes. Additionally, niacin could have other effects (not mediated by GPR109A) that could have a positive impact on high blood pressure.

Niacin and the lowering of cholesterol and triglycerides

Niacin is recommended by some experts to help lower low-density lipoprotein (LDL) or bad cholesterol levels within the body. Because of its ability to promote the break down of fats niacin has a potential role to play in the prevention and treatment of cardiovascular disease. Some cardiologists prescribe 3 grams of niacin per day or even higher amounts for patients with very high cholesterol levels. Unfortunately, at this high level, niacin has negative side effects. It should be noted that numerous studies have shown that for 67% of patients a dose of 3,000 mgs or more of daily niacin still did not promote the lowering of cholesterol. Additionally, the other form of Vitamin B3, niacinamide had no effect on cholesterol what so ever.

Other studies involving pharmacological doses of niacin have indicated that it can reverse atherosclerosis by reducing total cholesterol, triglyceride, very-low-density lipoprotein (VLDL), and LDL; and increase high-density lipoprotein (HDL). It has been proposed that niacin has the ability to lower lipoprotein(a) which is beneficial in reducing thrombotic tendency.

Niacin, prescribed at doses between 1000 and 2000 mg taken two to three times daily, blocks the breakdown of fats in adipose tissue, more specifically VLDL, the precursor of LDL. Because niacin blocks the breakdown of fats, it results in a decrease in free fatty acids in the blood and, as a consequence, decreased secretion of VLDL and cholesterol by the liver.

By lowering VLDL levels, niacin also increases the level of HDL or “good” cholesterol in the blood, and therefore it is sometimes prescribed for patients with low HDL, that are also at high risk of a heart attack.

Niacin side effects

When used at lower doses, such as those found in a daily multi-vitamin (20 mg daily = 100% of RDA), niacin is very safe. However, pharmacological doses of niacin (1.5 – 6 g per day) often result in side effects that include:

Dermatological effects: Skin flushing due to dilation of blood vessels lasting about 15 to 30 minutes and itching, dry skin, skin rashes. Skin flushing is mediated by prostaglandin and can be blocked by ingesting 300 mg of aspirin about 30 minutes before taking niacin, or by taking one tablet of ibuprofen per day. Taking niacin with meals also helps to diminish this side effect. One clinical study demonstrated that the incidence of flushing was significantly lower with a sustained release niacin formulation, although doses above 2 g per day have been associated with liver damage, particularly with slow-release formulations.

Gastrointestinal effects: Dyspepsia (indigestion) and liver toxicity (fulminant hepatic failure).

Elevated blood sugar: High-dose niacin may also elevate blood sugar, thereby worsening diabetes mellitus.

Gout: Hyperuricemia is another side effect of taking high-dose niacin, and may exacerbate gout.

Birth defects: Niacin used at pharmacological doses has been associated with birth defects in laboratory animals, with possible consequences for infant development in pregnant women.

Maculopathy: Niacin taken at extremely high doses can also cause maculopathy, a thickening of the macula and retina which leads to blurred vision and blindness. This can be reversed by terminating niacin intake.

Also, avoid alcohol or hot beverages near the time of the niacin dose.

How to take niacin

Take this medication with food to prevent stomach upset. Follow any special dietary recommendations made by a doctor or nutritionist while taking this medication. If prescribed bile acid resin drugs (e.g. colestipol, cholestyramine) leave at least a 6 hours before taking niacin. Since alcohol can intensify drug side effects, ask a doctor or pharmacist about drinking alcohol while taking high dose niacin. If niacin is being used as a cholesterol treatment, breast-feeding is not recommended due to possible infant side effects. Consult a doctor before you breast-feeding.

Niacin dosage

The recommended daily dose of niacin is 2–12 mg/day for children, 14 mg/day for women, 16 mg/day for men and 18 mg/day for pregnant or breast-feeding women. The upper limit for adult men and women is 35 mg/day which is based on flushing as the critical side effect, at 10 to 20 minutes after niacin is taken.

Niacin drug interactions

Inform a doctor if taking over-the-counter or prescription drugs especially: high blood pressure drugs, diabetes medicine, fibrates (e.g. gemfibrozil, fenofibrate) or statins (e.g. lovastatin, atorvastatin). If taking insulin or oral diabetes medication, the dosage may need to be altered due to increased blood sugar levels caused by niacin. Do not start or stop any medicine without doctor or pharmacist approval.

Niacin in food

Niacin is found in variety of foods including liver, chicken, beef, fish, cereal, nuts, mushrooms, brewer’s yeast, avocados, dates, tomatoes, leaf vegetables, broccoli, carrots, sweet potatoes, asparagus, dairy products and eggs.

NOTE: This information is given for educational purposes only and should not be used for the diagnosis, treatment or prevention of disease. It should not be used to replace the services of a qualified practitioner.