Natural treatments for hypertension

DEFINITION: Treatment of the conditions that cause blood pressure to rise to abnormal, dangerous levels.

PRINCIPAL PROPOSED NATURAL TREATMENTS: Coenzyme Q₁₀, relaxation therapies, Stevia rebaudiana

OTHER PROPOSED NATURAL TREATMENTS: Acupuncture, Ayurvedic herbal combinations, bacailin, barberry, biofeedback, black tea, calcium, chocolate, Cordyceps, fiber, fish oil, Eclipta alba, gamma-aminobutyric acid, garlic, glucomannan, green coffee bean extract, grape juice, hibiscus, Achillea wilhelmsii, maca, magnesium, melatonin, milk fermented by probiotics, olive leaf, potassium, qigong, quercetin, soy, Tai Chi, vitamin C

HERBS AND SUPPLEMENTS TO USE ONLY WITH CAUTION: Citrus aurantium, soy isoflavones, vitamin C plus oligomeric proanthocyanidins, vitamin E

Introduction

Most people cannot tell when their blood pressure is high, which is why hypertension is called the “silent killer.” 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 a major cause 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 somewhat similar to what happens in a hose fitted with a high-pressure nozzle. All such nozzles come with a warning label that states that pressure in the hose should be discharged after use. Many people, however, leave the hose with full pressure after using it. This rather common practice does not produce any immediate consequences. The hose does not develop leaks at the seams or burst outright on the first occasion it is left 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 develop and show leaks.

When human blood vessels are exposed to constant high pressure, a similar process is set in motion. Blood pressure that elevates to, for example, a reading of 220/170 (systolic pressure/diastolic pressure), which is quite common during certain physical activities such as weight lifting, do no harm. Only when excessive pressure is sustained do blood vessel linings begin to be injured and undergo the unhealthy changes known as atherosclerosis.

Although it is important to lower blood pressure, it rarely needs to be lowered instantly. In most situations, a person has plenty of time to reduce blood pressure. However, this does not mean that one should ignore it. Over time, high blood pressure can damage nearly every organ in the body.

The best way to determine one’s 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 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 that may have been caused by stress, for example. To record an accurate number, all measurements must be included in the calculations.

In most cases, the cause of hypertension is unknown. The kidneys play an essential role in controlling blood pressure. Other factors include hormones, genetic factors, and health conditions like diabetes. Lifestyle changes like quitting smoking, losing weight, and increasing exercise can dramatically reduce blood pressure. One study found that sixty to ninety minutes of weekly aerobic exercise may be sufficient for producing maximum benefits. Another study found that taking ten-minute brisk walks four times daily significantly improves blood pressure. Diet plays a large role in hypertension risk, but every individual’s nutritional needs differ. Salt is commonly blamed for hypertension, but this is not the case for every individual. Each person must be evaluated to determine a proper nutrition plan to address the causes of their hypertension. If lifestyle changes fail to reduce blood pressure, or if one cannot make these alterations, many effective drugs are available. Sometimes, experimentation with a few drugs helps find the most effective one.

Principal Proposed Natural Treatments

There are no herbs or supplements for hypertension with solid scientific support. However, the supplement coenzyme Q₁₀ and extracts from the herb Stevia rebaudiana have shown some promise in preliminary trials.

Coenzyme Q₁₀. The supplement coenzyme Q10 (CoQ₁₀) has shown promise as a treatment for high blood pressure, but the evidence that it works is not strong. An eight-week, double-blind, placebo-controlled study of fifty-nine men already taking medication for high blood pressure found that 120 milligrams (mg) daily of CoQ₁₀ reduced blood pressure by about 9 percent compared with placebo. In addition, a twelve-week, double-blind, placebo-controlled study of eighty-three people with isolated systolic hypertension (a type of high blood pressure in which only the “top” number is high) found that the use of CoQ₁₀ at a dose of 60 mg daily improved blood pressure measurements to a similar extent.

Also, in a twelve-week, double-blind, placebo-controlled trial of seventy-four people with diabetes, the use of CoQ₁₀ at a dose of 100 mg twice daily significantly reduced blood pressure compared with placebo. Antihypertensive effects were also seen in earlier smaller trials, but most of them were not double-blind, so they mean little.

Stevia rebaudiana. The herb Stevia rebaudiana is best known as a sweetener. Its active ingredients are known as steviosides. In a one-year, double-blind, placebo-controlled study of 106 people in China with moderate hypertension (approximate blood pressure of 165/103), steviosides at a dose of 250 mg three times daily reduced blood pressure by approximately 10 percent. Full benefits took months to develop. However, this study is notable for finding no benefits in the placebo group. This is unusual and tends to cast doubt on the results.

Benefits also were reported in a two-year, double-blind, placebo-controlled study, also in China, of 174 people with milder hypertension (average initial blood pressure of approximately 150/95). This study used twice the dose of the previous study: 500 mg three times daily. A reduction in blood pressure of approximately 6 to 7 percent was seen in the treatment group compared with the placebo group, beginning within one week and enduring throughout the two years of the study. At the end of the study, 34 percent of those in the placebo group showed heart damage from high blood pressure (left ventricular hypertrophy), while only 11.5 percent of the stevioside group did, a difference that was statistically significant. No significant adverse effects were seen. However, once again, no benefits were seen in the placebo group. This is a red flag for problems in study design. Furthermore, a study by an independent set of researchers failed to replicate these findings.

Another study involving people with diabetes and healthy persons found that stevia, at a dose of 250 mg three times daily, had no significant effect on blood pressure after three months of treatment. A study by an independent set of researchers failed to replicate these findings.

Relaxation therapies. Although it seems intuitive that relaxation should lower blood pressure, the evidence for the benefits of relaxation therapies for treating hypertension is far from convincing. In a review of twenty-five studies investigating various relaxation therapies (totaling 1,198 participants), researchers found that those studies employing a control group reported no significant effect on lowering blood pressure compared to sham (placebo) therapies.

More specifically, biofeedback is widely advocated for treating hypertension. However, in an analysis of twenty-two studies, real biofeedback when used alone was found to be no more effective than sham (fake) biofeedback. A subsequent review of thirty-six trials with 1,660 participants found inconsistent evidence for the effectiveness of biofeedback for the treatment of hypertension in comparison to drug therapy, sham biofeedback, no intervention, or other relaxation techniques.

However, some studies have been supportive. A review of nine randomized trials concluded that the regular use of Transcendental Meditation significantly reduced both systolic and diastolic blood pressure compared to a control. Similarly, an analysis of seventeen randomized controlled trials of various relaxation therapies found that only Transcendental Meditation resulted in significant reductions in blood pressure. Biofeedback, progressive muscle relaxation, and stress management training produced no such benefit. In addition, a trial of eighty-six persons with hypertension suggested that daily, music-guided, slow breathing reduced systolic blood pressure measured in a twenty-four-hour period. However, later research confirmed the use of biofeedback as an adjuvant treatment with drugs for diastolic blood pressure treatment.

Other Proposed Natural Treatments

The Iranian herb Achillea wilhelmsii was tested in a double-blind trial of sixty men and women with mild hypertension. The results showed that treatment with an A. wilhelmsii extract significantly reduced blood pressure readings. Also, in a double-blind study of forty-three men and women with hypertension, the use of a proprietary Ayurvedic herbal combination containing Terminali arjuna and about forty other herbs proved almost as effective for controlling blood pressure as the drug methyldopa.

Although the research record is mixed, it appears that fish oil may reduce blood pressure, at least slightly. Fish oil contains two major active ingredients, DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid). Some evidence suggests that it is the DHA in fish oil, not the EPA, that is responsible for this benefit.

Several studies have found that glucomannan, a dietary fiber derived from the tubers of Amorphophallus konjac, may improve high blood pressure. Other forms of fiber also may be helpful.

Milk fermented by certain probiotics (friendly bacteria) may provide a small blood-pressure-lowering effect. Also, growing evidence supports the use of a green coffee bean extract for high blood pressure. Three preliminary double-blind studies found that chocolate (high in polyphenols) might help mild hypertension. A review including several additional studies drew a similar conclusion.

Because of its active ingredient S-allyl cysteine, garlic has been investigated as a natural hypertension treatment. S-allyl cysteine is thought to relax smooth muscle by regulating nitric oxide and promoting hydrogen sulfide production. Numerous studies have found weak evidence that garlic lowers blood pressure slightly, perhaps 5 to 10 percent more than placebo. Other studies found more positive results, but only with very high levels of garlic. Additionally, individuals with elevated systolic blood pressure experienced improvements, but these results were not replicated in those with elevated systolic blood pressure. It remains unclear whether garlic supplements can help persons with high blood pressure safely eliminate or avoid antihypertensive medications.

Hawthorn (Crataegus spp.) may help improve hypertension in some individuals in combination with other medications. In a review of four studies conducted in the early twenty-first century, many patients experienced a positive impact on hypertension with few adverse side effects and risks. It can be taken with many hypertension medications and is available in several forms, including tea. Before beginning this supplement, patients should consult their doctor because drug interactions can occur.

People who are deficient in calcium may be at great risk of developing high blood pressure. Among people who already have hypertension, increased intake of calcium might slightly decrease blood pressure, according to some studies. In an extremely large, randomized, placebo-controlled trial involving 36,282 postmenopausal women, 1,000 mg of calcium plus 400 international units of vitamin D given daily did not significantly reduce blood pressure in seven years in women with or without hypertension. Weak evidence hints that the use of calcium by pregnant women might reduce the risk of hypertension in their children. Also, study results are mixed on whether magnesium or potassium supplements can improve blood pressure. At most, the benefit is likely quite small.

In a thirty-day, double-blind, placebo-controlled study of thirty-nine people taking medications for hypertension, treatment with 500 mg of vitamin C daily reduced blood pressure by about 10 percent. Smaller benefits were seen in studies of people with normal blood pressure or borderline hypertension. One double-blind study compared 500, 1,000, and 2,000 mg of vitamin C and found an equivalent level of benefit in all three groups. (Because of the lack of a placebo group, this study cannot be used as proof of effectiveness, only as a demonstration of the equivalence of the doses.) However, other studies have failed to find evidence of benefit with vitamin C. This mixed evidence suggests, on balance, that if vitamin C does have any blood-pressure-lowering effect, it is at most quite modest.

One study found that a combination of vitamin C (500 mg daily) and grape seed oligomeric proanthocyanidins (1,000 mg daily) slightly increased blood pressure. Whether this was a fluke of statistics or a real combined effect remains unclear.

Other studies suggest possible benefit with the Ayurvedic herb Eclipta alba (also known as Bhringraja or Keshraja), beta-hydroxy-beta-methylbutyrate, theanine from black tea, blue-green algae products, chitosan, concord grape juice, garlic, gamma-aminobutyric acid, kelp, lipoic acid combined with carnitine, quercetin, Salvia hispanica (a grain), and sweetie fruit (a grapefruit and pummelo hybrid high in citrus bioflavonoids). However, the supporting evidence cannot be considered reliable for any of these treatments.

There is mixed evidence on whether soy protein and its associated isoflavones are helpful for blood pressure. A comprehensive review of studies investigating the influence of phytoestrogens (including soy) on blood pressure found no meaningful effect. However, another review found that soy protein alone could significantly reduce blood pressure.

Three small, double-blind, placebo-controlled studies found evidence that melatonin may slightly reduce nighttime blood pressure. Getting adequate vitamin D may help prevent the development of hypertension. The vitamin folate may help decrease blood pressure (and might provide other heart-healthy effects) in smokers.

The herbs astragalus, barberry, Coleus forskohliibacailin, hibiscus, maitake, maca, and olive leaf, and the supplements beta-carotene, Cordyceps, flaxseed oil, royal jelly, and taurine, are sometimes recommended for high blood pressure, but there is no meaningful evidence that they work. Also, reducing homocysteine with B vitamins does not appear to reduce blood pressure in healthy people with high homocysteine.

One study was quoted as having shown that a traditional Chinese herbal formula can reduce blood pressure, but the study actually failed to find any effect on blood pressure. In a review of twenty-six published studies examining the effectiveness of Tai Chi for high blood pressure, 85 percent demonstrated a reduction in blood pressure. However, only five of these twenty-six studies were of acceptable quality.

A substantial study (192 participants) failed to find acupuncture helpful for high blood pressure. However, another study, this one enrolling 160 people, did report benefit, but the study was small and had problems in its use of statistics. In a review of eleven randomized-controlled trials on the subject, researchers determined that acupuncture’s ability to lower blood pressure remains inconclusive.

The alternative therapies hatha yoga, qigong, and Tai Chi have shown some potential benefits for high blood pressure, the mechanism of action probably being similar for each. A later review of multiple studies investigating the effectiveness of self-practiced qigong, for example, concluded that this therapy was more effective at lowering blood pressure than no- treatment controls. However, it was no more effective than standard treatments for hypertension: antihypertensive medications or conventional exercise.

In a twelve-week study of 140 men and women with stage I hypertension, chiropractic spinal manipulation plus dietary change did not produce any greater benefit than dietary change alone. For many years, the American Heart Association and other major foundations have recommended reducing saturated fat and increasing carbohydrates in one’s diet. However, growing evidence suggests that it is preferable to keep carbohydrate levels relatively low while replacing saturated fat with monounsaturated fats such as olive oil.

Herbs and Supplements to Use with Caution

One highly credible case report of severe and dangerous hypertension was caused by the consumption of isoflavones made from soy during a clinical trial on this supplement. This is most likely a rare, highly individual response, but if it could occur with one person, it also could occur with another.

As noted, in one study, a combination of vitamin C and grape seed oligomeric proanthocyanidins mildly increased blood pressure. In another study, the use of vitamin E raised blood pressure in people with type 2 diabetes.

The herb Citrus aurantium (bitter orange) may increase blood pressure. In addition, various herbs and supplements may interact adversely with drugs used to treat hypertension.

Bibliography

Anderson, J. W., et al. “Blood Pressure Response to Transcendental Meditation.” American Journal of Hypertension, vol. 21, 2008, pp. 310–16.

Erkkila, A. T., et al. “Effects of Fatty and Lean Fish Intake on Blood Pressure in Subjects with Coronary Heart Disease Using Multiple Medications.” European Journal of Nutrition, vol. 47, 2008, pp. 319–28.

Heather, O. D., et al. “Relaxation Therapies for the Management of Primary Hypertension in Adults.” Cochrane Database of Systematic Reviews (2008): CD004935. EBSCO DynaMed Systematic Literature Surveillance.

“High Blood Pressure.” MedlinePlus, US National Lib. of Medicine, 28 May 2024, medlineplus.gov/highbloodpressure.html. Accessed 20 Sept. 2024.

Hooper, L., et al. “Flavonoids, Flavonoid-Rich Foods, and Cardiovascular Risk.” American Journal of Clinical Nutrition, vol. 88, 2008, pp. 38–50.

Jenkins, S., et al. "Effectiveness of Biofeedback on Blood Pressure in Patients with Hypertension: Systematic Review and Meta-Analysis." Journal of Human Hypertension, 2024, doi.org/10.1038/s41371-024-00937-y.

Lee, H., et al. “Acupuncture for Lowering Blood Pressure.” American Journal of Hypertension, vol. 22, 2009, pp. 122–28.

Margolis, K. L., et al. “Effect of Calcium and Vitamin D Supplementation on Blood Pressure.” Hypertension, vol. 52, 2008, pp. 847–55.

Ried, K., et al. “Effect of Garlic on Blood Pressure.” BMC Cardiovascular Disorders, vol. 9, 2008, p. 13.

Rogers, P. J., et al. “Time for Tea: Mood, Blood Pressure, and Cognitive Performance Effects of Caffeine and Theanine Administered Alone and Together.” Psychopharmacology, vol. 195, 2008, pp. 569–77.

"Ten Ways to Control High Blood Pressure without Medication.” Mayo Clinic, 23 July 2024, www.mayoclinic.org/diseases-conditions/high-blood-pressure/in-depth/high-blood-pressure/art-20046974. Accessed 20 Sept. 2024.