Approximately 90% of people with high blood pressure have “essential” or “idiopathic” hypertension, for which the cause is poorly understood. The terms “hypertension” and “high blood pressure” as used here refer only to this most common form and not to pregnancy-induced hypertension or hypertension clearly linked to a known cause, such as Cushing’s syndrome, pheochromocytoma, or kidney disease. Hypertension must always be evaluated by a healthcare professional. Extremely high blood pressure (malignant hypertension) or rapidly worsening hypertension (accelerated hypertension) almost always requires treatment with conventional medicine. People with mild to moderate high blood pressure should work with a doctor before attempting to use the information contained here, as blood pressure requires monitoring and in some cases the use of blood pressure-lowering drugs.
As with conventional drugs, the use of natural substances sometimes controls blood pressure if taken consistently but does not lead to a cure for high blood pressure. Thus, someone whose blood pressure is successfully reduced by weight loss, avoidance of salt, and increased intake of fruits and vegetables would need to maintain these changes permanently in order to retain control of blood pressure. Left untreated, hypertension significantly increases the risk of stroke and heart disease.
What are the symptoms of hypertension?
Essential hypertension is usually without symptoms until complications develop. The symptoms of complications depend on the organs involved.
Dietary changes that may be helpful for hypertension
Primitive societies exposed to very little salt suffer from little or no hypertension.1 Salt (sodium chloride) intake has also been definitively linked to hypertension in western societies.2 Reducing salt intake in the diet lowers blood pressure in most people.3' The more salt is restricted, the greater the blood pressure-lowering effect.4 Individual studies sometimes come to differing conclusions about the relationship between salt intake and blood pressure, in part because blood pressure-lowering effects of salt restriction vary from person to person, and small to moderate reductions in salt intake often have minimal effects on blood pressure—particularly in young people and in those who do not have hypertension. Nonetheless, dramatic reductions in salt intake are generally effective for many people with hypertension.
With the prevalence of salted processed and restaurant food, simply avoiding the salt shaker no longer leads to large decreases in salt intake for most people. Totally eliminating salt is more effective, but is quite difficult to achieve. Moreover, while an overview of the research found “There is no evidence that sodium reduction presents any safety hazards,”5 reports of short-term paradoxical increases in blood pressure in response to salt restriction have occasionally appeared.6 Therefore, people wishing to use salt reduction to lower their blood pressure should consult with a doctor.
Vegetarians have lower blood pressure than do people who eat meat.7 This occurs partly because fruits and vegetables contain potassium—a known blood pressure-lowering mineral.8 The best way to supplement potassium is with fruit, which contains more of the mineral than do potassium supplements. However, fruit contains so much potassium that people taking “potassium-sparing”diuretics can consume too much potassium simply by eating several pieces of fruit per day. Therefore, people taking potassium-sparing diuretics should consult the prescribing doctor before increasing fruit intake. In the Dietary Approaches to Stop Hypertension (DASH) trial, increasing intake of fruits and vegetables (and therefore fiber) and reducing cholesterol and dairy fat led to large reductions in blood pressure (in medical terms, 11.4 systolic and 5.5 diastolic) in just eight weeks.9 Even though it did not employ a vegetarian diet itself, the outcome of the DASH trial supports the usefulness of vegetarian diets because diets employed by DASH researchers were related to what many vegetarians eat. The DASH trial also showed that blood pressure can be significantly reduced in hypertensive people (most dramatically in African Americans) with diet alone, without weight loss or even restriction of salt.1011 Nonetheless, restricting salt while consuming the DASH diet has lowered blood pressure even more effectively than the use of the DASH diet alone.
Sugar has been reported to increase blood pressure in animals12 and humans in short-term trials.13 Though the real importance of this experimental effect remains unclear,14 some doctors recommend that people with high blood pressure cut back on their intake of sugar.
Right after consuming caffeine from coffee or tea, blood pressure increases briefly.15 1617 The effects of long-term avoidance of caffeine (from coffee, tea, chocolate, cola drinks, and some medications) on blood pressure remain unclear. A few reports have even claimed that long-term coffee drinkers tend to have lower blood pressure than those who avoid coffee.18 Despite the lack of clarity in published research, many doctors tell people with high blood pressure to avoid consumption of caffeine. In trials lasting almost two months on average, coffee drinking has led to small increases in blood pressure.
Several double-blind trials have shown that adding 6.5–7 grams of fiber per day to the diet for several months leads to reductions in blood pressure.19 20 21 However, other trials have not found fiber helpful in reducing blood pressure.22 23 The reasons for these discrepant findings is not clear.
Food allergy was reported to contribute to high blood pressure in a study of people who had migraine headaches.24 In that report, all 15 people who also had high blood pressure experienced a significant drop in blood pressure when put on a hypoallergenic diet. People who suffer migraine headaches and have hypertension should discuss the issue of allergy diagnosis and elimination with a doctor.
Exposure to lead and other heavy metals has been linked to high blood pressure in some,25 but not all, research.26 If other approaches to high blood pressure prove unsuccessful, it makes sense for people with hypertension to have their body’s burden of lead evaluated by a healthcare professional.
Lifestyle changes that may be helpful for hypertension
Smoking is particularly injurious for people with hypertension.27 The combination of hypertension and smoking greatly increases the risk of heart disease-related sickness and death. All people with high blood pressure need to quit smoking.
Consumption of more than about three alcoholic beverages per day appears to increase blood pressure.28 Whether one or two drinks per day meaningfully increases blood pressure remains unclear.
Daily exercise can lower blood pressure significantly.29 A 12-week program of Chinese T’ai Chi was reported to be almost as effective as aerobic exercise in lowering blood pressure.30 Progressive resistance exercise (e.g., weight lifting) also appears to help reduce blood pressure.31 At the same time, blood pressure has been known to increase significantly during the act of lifting heavy weights; for this reason, people with sharply elevated blood pressure, especially those with cardiovascular disease, should approach heavy strenuous resistance exercise with caution. In general, people over 40 years of age should consult with their doctors before starting any exercise regimen.
Most people with high blood pressure are overweight. Weight loss lowers blood pressure significantly in those who are both overweight and hypertensive.32 In fact, reducing body weight by as little as ten pounds can lead to a significant reduction in blood pressure.3334 Weight loss appears to have a stronger blood pressure-lowering effect than dietary salt restriction.
Nutritional supplements that may be helpful for hypertension
Both preliminary35 36 37 and double-blind38 39 trials have reported that supplementation with Coenzyme Q10 (CoQ10) leads to a significant decrease in blood pressure in people with hypertension. Much of this research has used 100 mg of CoQ10 per day for at least ten weeks.
EPA and DHA, the omega-3 fatty acids found in fish oil, lower blood pressure, according to an analysis of 31 trials.40 The effect was dependent on the amount of omega-3 oil used, with the best results occurring in trials using unsustainably high levels: 15 grams per day—the amount often found in 50 grams of fish oil. Although results with lower intakes were not as impressive, trials using over 3 grams per day of omega-3 (as typically found in ten 1,000 mg pills of fish oil) also reported significant reductions in blood pressure. One double-blind trial reported that DHA had greater effects on blood pressure than EPA or mixed fish oil supplements.41 DHA is now available as a supplement separate from EPA.
Potassium supplements in the amount of at least 2,400 mg per day lower blood pressure, according to an analysis of 33 trials.42 However, potassium supplements greater than 100 mg per tablet require a prescription, and the low-dose potassium supplements available without a prescription can irritate the stomach if taken in large amounts. Moreover, some people, such as those taking potassium-sparing diuretics, should not take potassium supplements. Therefore, the use of potassium supplements for lowering blood pressure should only be done under the care of a doctor.
Some,43 but not all,44 trials show that magnesium supplements—typically 350–500 mg per day—lower blood pressure. Magnesium appears to be particularly effective in people who are taking potassium-depleting diuretics.45 Potassium-depleting diuretics also deplete magnesium. Therefore, the drop in blood pressure resulting from magnesium supplementation in people taking these drugs may result from overcoming a mild magnesium deficiency.
Calcium supplementation—typically 800–1,500 mg per day—may lower blood pressure. However, while an analysis of 42 trials reported that calcium supplementation led to an average drop in blood pressure that was statistically significant, the actual decrease was small (in medical terms, a drop of 1.4 systolic over 0.8 diastolic pressure).46 Results might have been improved had the analysis been limited to studies of people with hypertension, since calcium has almost no effect on the blood pressure of healthy people. In the analysis of 42 trials, effects were seen both with dietary calcium and with use of calcium supplements. A 12-week trial of 1,000 mg per day of calcium accompanied by blood pressure monitoring is a reasonable way to assess efficacy in a given person.
Five double-blind trials have found that vitamin C supplementation reduces blood pressure, but the reduction was statistically significant in only three of the five, and in most cases reductions were modest.47 48 Some doctors recommend that people with elevated blood pressure supplement with 1,000 mg vitamin C per day.
In a double-blind study of people with high blood pressure, 200 IU of vitamin E per day taken for 27 weeks was significantly more effective than a placebo at reducing both systolic and diastolic blood pressure.49 This study was done in Iran, and it is not clear whether the results would apply to individuals consuming a Western diet.
A deficiency of the amino acid taurine, is thought by some researchers to play an important role in elevating blood pressure in people with hypertension.50 Limited research has found that supplementation with taurine lowers blood pressure in animals51 and in people (at 6 grams per day),52 possibly by reducing levels of the hormone epinephrine (adrenaline).
The amino acid arginine is needed by the body to make nitric oxide, a substance that allows blood vessels to dilate, thus leading to reduced blood pressure. Intravenous administration of arginine has reduced blood pressure in humans in some reports.53 In one controlled trial, people not responding to conventional medication for their hypertension were found to respond to a combination of conventional medication and oral arginine (2 grams taken three times per day.)54
Are there any side effects or interactions with hypertension?
Refer to the individual supplement for information about any side effects or interactions.
Herbs that may be helpful for hypertension
In a double-blind trial, people with mild hypertension took a tincture of Achillea wilhelmsii, an herb used in traditional Persian medicine.55 Participants in the trial used 15–20 drops of the tincture twice daily for six months. At the end of the trial, participants experienced significant reductions in both systolic and diastolic blood pressure compared to those who took placebo. No adverse effects were reported.
Garlic has a mild blood pressure-lowering effect, according to an analysis of ten double-blind trials.56 All of these trials administered garlic for at least four weeks, typically using 600–900 mg of garlic extract per day. Onion—closely related to garlic—may also have a mild blood pressure-lowering effect, according to preliminary research.57
European mistletoe (Viscum album) has reduced headaches and dizziness associated with high blood pressure, according to preliminary research.58 Mistletoe may be taken as 0.5 ml tincture three times per day.59 The blood pressure-lowering effect of mistletoe is small and may take weeks to become evident. Due to possible serious side effects, European mistletoe should only be taken under the careful supervision of a physician trained in its use.
Indian snakeroot (Rauwolfia serpentina) contains powerful alkaloids, including reserpine, that affect blood pressure and heart function. Indian snakeroot has been used traditionally to treat hypertension, especially when associated with stress and anxiety.60 Due to possible serious side effects, Indian snakeroot should only be taken under the careful supervision of a physician trained in its use.
In animal studies oleuropein, one of the constituents of olive leaf, has decreased blood pressure and dilated arteries surrounding the heart, when given by injection or intravenously.61 Olive leaf has been used traditionally to treat people with hypertension,62 but controlled human trials are needed before a blood pressure-lowering effect can be established.
A double-blind trial reported that reishi mushrooms significantly lowered blood pressure in humans.63 The trial used a concentrated extract of reishi (25:1) in the amount of 55 mg three times per day for four weeks. It is unclear from the clinical report how long it takes for the blood pressure-lowering effects of reishi to be measured.
Hawthorn leaf and flower extracts have been reported to have a mild blood pressure-lowering effect in people with early stage congestive heart failure.64 This effect has not been studied in hypertensive people with normal heart functioning.
Human trials investigating the use of Coleus forskohlii in blood pressure reduction have yet to be conducted. However, forskolin, the active ingredient in Coleus forskohlii, has lowered blood pressure in a small, preliminary trial with people suffering from cardiomyopathy.65 Extracts of coleus standardized to contain 15–20% forskolin are available, but further trials are needed to determine effective levels for treating people with hypertension.
Most herbal reference books suggest that ginseng should not be used by people with hypertension. However, the results of a preliminary trial suggest that red ginseng root (Panax ginseng radix rubra) has either no effect on, or may actually slightly lower, blood pressure in hypertensive people.66 However, many herbalists continue to believe that people with hypertension should avoid Asian ginseng and American ginseng, and, while not a true ginseng, Siberian ginseng (eleuthero) as well.
In a controlled trial, people with hypertension received either Hibiscus tea (Hibiscus sabdariffa) or ordinary tea daily.67 Two tablespoons of dried herb were boiled in one cup of water for 20 to 30 minutes and consumed daily for 12 days. By the final day, blood pressure was 11% lower in the treatment group, compared to only 4% in the control group.
Are there any side effects or interactions with hypertension?
Refer to the individual herb for information about any side effects or interactions.
Holistic approaches that may be helpful for hypertension
Anxiety in men (but not women) has been linked to development of hypertension.68 Several research groups have also shown a relationship between job strain and high blood pressure in men.69 70 71 Some researchers have tied blood pressure specifically to suppressed aggression.72
Although some kind of relationship between stress and high blood pressure appears to exist, the effects of treatment for stress remain controversial. An analysis of 26 trials reported that reductions in blood pressure caused by biofeedback or meditation were no greater than those seen with placebo.73 Though some stress management interventions have not been helpful in reducing blood pressure,74 75 those trials that have reported promising effects have used combinations of yoga, biofeedback, and/or meditation.76 77 78 Some doctors continue to recommend a variety of stress-reducing measures, sometimes tailoring them to the needs and preferences of the person seeking help.
Preliminary laboratory studies in animals79 and humans80 81 82 suggest that acupuncture may help regulate blood pressure. Most,83 84 85 86 87 88 but not all,89 preliminary trials also suggest that acupuncture may be an effective way to lower blood pressure. Whether blood pressure goes back up after acupuncture is discontinued remains an unsettled question.
Auricular (ear) acupressure has been reported to be an effective treatment for hypertension,90 91 92 though in one case the improvement was not significantly better than use of traditional herbal medicines.93
Spinal manipulation may lower blood pressure (at least temporarily) in healthy people, according to most preliminary94 95 96 and controlled97 trials. However, some research suggests the effect is no better than the blood pressure-lowering effect of sham (“fake”) manipulation.98 In hypertensive people, temporary decreases in blood pressure have also been reported after spinal manipulation.99 100 101 However, most,102 103 104 but not all,105 trials suggest that manipulation produces only short-term decreases in blood pressure in hypertensive people.