Conditions:
Hypertension

Related Terms
  • High Blood Pressure
Principal Proposed Treatments
  • Garlic, Coenzyme Q10 (CoQ10), Stevia
Other Proposed Treatments
  • Fish Oil, Calcium, Magnesium, Potassium, Hawthorn, Vitamin C, Achillea wilhelmsii, Glucomannan, Hibiscus, OPCs (Oligomeric Proanthocyanidins), Kelp, Blue Green Algae, Astragalus, Coleus forskohlii, Maitake, Beta-Carotene, Flaxseed Oil, Taurine

Most people can't tell when their blood pressure is high, which is why hypertension is called the "silent killer." In this case, what you don't know can hurt you. Elevated blood pressure can lead to a greatly increased risk of heart attack, stroke, and many other serious illnesses. Along with high cholesterol and smoking, hypertension is one of the most important causes of atherosclerosis. In turn, atherosclerosis causes heart attacks, strokes, and other diseases of impaired circulation.

The mechanism by which high blood pressure produces atherosclerosis is similar to a hose fitted with a high-pressure nozzle. All such nozzles come with a warning label that states, "Make sure to discharge pressure in hose after using." Unfortunately, many people frequently fail to pay attention to the warning and leave the hose puffed up with full pressure overnight.

This rather common practice does not produce any immediate consequences. The hose doesn't develop leaks at the seams or burst outright on the first occasion you leave it untended. However, a garden hose that is frequently left under pressure will begin to age more rapidly than it would otherwise. Its lining will begin to crack, its flexibility will diminish, and within a season or two the hose will be sprouting leaks in all directions.

When blood vessels are exposed to constantly high pressure, a similar process is set in motion. Blood pressures as elevated as 220/170 (systolic pressure/diastolic pressure), quite common during activities such as weight lifting, do no harm. Only when excessive pressure is sustained day and night do blood vessel linings begin to be injured and undergo those unhealthy changes known as hardening of the arteries, or atherosclerosis (see the article on atherosclerosis for more information).

Thus, although it is important to lower blood pressure with all deliberate speed, only rarely does it need to be lowered instantly. In most situations, you have plenty of time to work on bringing down your blood pressure. However, that doesn't mean that you should ignore it. Over time, high blood pressure can damage nearly every organ in the body.

The best way to determine your blood pressure is to take several readings at different times during the day and on different days of the week. Blood pressure readings will vary quite a bit from moment to moment; what matters most is the average blood pressure. Thus, if many low readings balance out a few high readings, the net result may be satisfactory.

However, it is essential not to ignore a high value by saying, "I was just stressed then." Stress is part of life, and if it raises your blood pressure once, it will do so again. To come up with an accurate number, you must include every measurement in your calculations.

In most cases, the cause of hypertension is unknown. The kidneys play an important role in controlling blood pressure, and the level of squeezing tension in the blood vessels makes a large contribution as well.

Lifestyle changes can dramatically reduce blood pressure. Increasing exercise, not smoking, and losing weight can all be highly effective. For many years doctors advised patients with hypertension to cut down on salt in the diet. Today, however, the value of this difficult dietary change has undergone significant questioning. Considering how rapidly our knowledge is evolving, we suggest consulting your physician to find the latest recommendations.

If lifestyle changes fail to reduce blood pressure, or if you can't make these alterations, many effective drugs are available. Sometimes you need to experiment with a few to find one that agrees with you.

Principal Proposed Treatments for Hypertension

Although there are no well-documented natural treatments for hypertension, garlic and coenzyme Q₁₀ have some evidence behind them. Keep in mind that when blood pressure is consistently higher than 160/110, nondrug treatments (other than lifestyle changes) are seldom enough to bring it down.

Garlic: Might Reduce Blood Pressure by 5 to 10%

Numerous studies have found weak evidence that garlic lowers blood pressure slightly, perhaps in the neighborhood of 5 to 10% more than placebo.^1,2,3 However, all of these studies suffered from significant flaws, and most were performed on people who did not have high blood pressure. At present, it is not clear whether garlic actually has any effects on blood pressure.

One study followed 47 subjects with an average starting blood pressure of 171/101.⁴ Over a period of 12 weeks, half were treated with 600 mg of garlic powder daily standardized to 1.3% alliin, the other half were given placebo. The results showed a statistically significant drop of 11% in the systolic blood pressure and 13% in the diastolic pressure. In comparison, blood pressure fell in the placebo group by 5% and 4%, respectively. However, this study suffers from a significant problem: the average starting blood pressure of the placebo and the treated groups were quite different, making comparisons unreliable.

For more information, including dosage and safety issues, see the full garlic article.

Coenzyme Q₁₀: Appears Effective, but Needs More Study

The supplement coenzyme Q₁₀ (CoQ₁₀) is commonly recommended as a treatment for high blood pressure, but the evidence that it works is not yet strong.

An 8-week double-blind placebo-controlled study of 59 men already taking medication for high blood pressure found that 120 mg daily of coenzyme Q₁₀ reduced blood pressure by about 9% as compared to placebo.⁷

A 12 week, double-blind, placebo-controlled study of 83 individuals with isolated systolic hypertension (a type of high blood pressure in which only the "top" number is high) found that use of CoQ₁₀ at a dose of 60mg daily improved blood pressure measurements to a similar extent. ⁵³

Similar results were seen in smaller trials, most of which were not double-blind.^8,9,10

For more information, including dosage and safety issues, see the full CoQ₁₀ article.

Stevia

An herb best known as a sweetener, stevia may also help reduce blood pressure.

A 1-year double-blind study of 106 individuals given stevia extract found evidence of a significant reduction in blood pressure beginning at 3 months.¹² In the treated group, the average blood pressure at the beginning of the study was about 166/102. By the end of the study, this had fallen to 153/90. In contrast, no significant reductions were seen in the placebo group.

For more information, including dosage and safety issues, see the full stevia article.

Other Proposed Treatments for Hypertension

A number of other herbs and supplements may also be somewhat helpful for hypertension.

Fish Oil

Fish oil, a source of omega-3 fatty acids, is also commonly described as beneficial in the treatment of hypertension. However, the research record is mixed and at best shows a slight benefit.^15–21

For more information, including dosage and safety issues, see the full fish oil article.

Minerals: May Be Effective in Case of Deficiency

Study results are mixed on whether magnesium or potassium supplements can improve blood pressure.^{22–26,51 27,28,54} The effect appears to be slight at best.

Observational studies have found associations between calcium deficiency and high blood pressure.^29,30 However, according to one study, taking supplemental calcium does not improve blood pressure measurements.³¹

Hawthorn

The herb hawthorn is often said to reduce blood pressure, but its effects appear to be marginal at best.^32,55 For more information, including dosage and safety issues, see the full hawthorn article.

Vitamin C: Possibly Effective

According to a 30-day double-blind study of 39 individuals taking medications for hypertension, treatment with 500 mg of vitamin C daily can reduce blood pressure by about 10%.³³ Smaller benefits were seen in studies of individuals with normal blood pressure or borderline hypertension.^34,35 Other studies have returned inconclusive results.^36,37

Other Treatments

The Iranian herb Achillea wilhelmsii was tested in a double-blind trial of 60 men and women with mild hypertension.³⁸ The results showed that treatment with an A. wilhelmsii extract significantly reduced blood pressure readings.

Several studies have found that glucomannan, a dietary fiber derived from the tubers of Amorphophallus konjac, may improve high blood pressure.^39,40,41

Weak evidence suggests that another type of fiber, chitosan, may inhibit the expected rise in blood pressure after a high-salt meal.⁴²

Highly preliminary evidence suggests that hibiscus tea⁴³and OPCs⁵² might be helpful for high blood pressure.

Animal studies suggest that kelp might help to lower blood pressure; however, we don't know if this effect would apply to humans.⁴⁴

Getting adequate vitamin D might help prevent developing hypertension.^45–49

Highly preliminary evidence suggests that blue green algae products might be helpful for reducing hypertension.⁵⁰

The herbs astragalus, Coleus forskohlii, and maitake, and the supplements beta-carotene, flaxseed oil, and taurine are sometimes recommended for high blood pressure, but as yet there is no real evidence that they work.

Because atherosclerosis is the main harm caused by hypertension, treatments listed in the article on atherosclerosis should be considered as well.

Last reviewed August 2002 by Medical Review Board

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