Complementary and Alternative Medicine Approaches to Blood Pressure Reduction: An Evidence-Based Review

ABSTRACT

Objective: To review the evidence supporting complementary and alternative medicine (CAM) approaches used in the treatment of hypertension.

Quality of Evidence: MEDLINE and EMBASE were searched from January 1966 to May 2008 combining the key words hypertension or blood pressure with acupuncture, chocolate, cocoa, coenzyme Q10, ubiquinone, melatonin, vitamin D, meditation, and stress reduction. Clinical trials, prospective studies, and relevant references were included.

Main Message: Evidence from systematic reviews supports the blood pressure–lowering effects of coenzyme Q10, polyphenol-rich dark chocolate, Qigong, slow breathing, and transcendental meditation. Vitamin D deficiency is associated with hypertension and cardiovascular risk; supplementation lowered blood pressure in two trials. Acupuncture reduced blood pressure in three trials; in one of these, it was no better than an invasive placebo. Melatonin was effective in two small trials, but caution is warranted in patients taking pharmacotherapy.

Conclusion: Several CAM therapies can be considered as part of an evidence-based approach to the treatment of hypertension. The potential benefit of these interventions warrants further research using cardiovascular outcomes.

High blood pressure (BP) is one of the most important cardiovascular risk factors worldwide. Only about one-third of patients achieve optimal BP control using drug therapy. A reduction of 5 mm Hg in systolic BP has been associated with a 7% reduction in all-cause mortality, so it is important to consider other interventions that reduce BP.

The Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure recommends five lifestyle changes for all patients with hypertension: reducing sodium intake, increasing exercise, moderating alcohol consumption, losing weight, and following the Dietary Approaches to Stop Hypertension (DASH) eating plan.

Less widely prescribed—but increasingly popular among patients—are complementary and alternative medicine (CAM) antihypertensive therapies. CAM describes therapies that are not widely taught in medical schools nor generally available in hospitals. Canadian use of CAM therapies is similar to that in the United States, where 36% of people regularly use CAM. This article reviews some CAM approaches to BP reduction and the clinical evidence supporting their use.

Quality of Evidence

MEDLINE and EMBASE were searched from January 1966 to May 2008 using keywords related to hypertension and various CAM interventions. Human clinical trials and prospective studies were selected, along with relevant references. The interventions were selected based on familiarity with CAM literature and popular use by patients and CAM practitioners.

Level I evidence was available for most of the interventions, although some studies had methodological limitations inherent to non-drug clinical trials, particularly relevant to acupuncture and mind-body trials.

Evidence Supporting CAM Approaches to BP Reduction

Detailed Review of Selected Interventions

Dark Chocolate: Rich in flavonoid polyphenols, dark chocolate has been shown to lower BP in several small trials and a meta-analysis of 5 randomized controlled trials. Regular consumption of smaller amounts of chocolate also demonstrated long-term BP reduction.

Coenzyme Q10: A meta-analysis of 12 clinical trials found that CoQ10 lowers BP significantly. While large, prospective, multicenter trials are needed, current evidence suggests it could be added to conventional antihypertensive therapy.

Melatonin: Preliminary evidence suggests that melatonin may lower BP, though caution is warranted in patients taking antihypertensive medication.

Vitamin D: Deficiency in vitamin D is associated with increased risk of hypertension and cardiovascular events. Short-term supplementation appears to lower BP, supported by evidence from prospective cohort studies and randomized trials.

Mind-Body Approaches: Qigong, slow breathing, and transcendental meditation have shown potential in lowering BP. Systematic reviews and meta-analyses support these findings, although the quality of evidence varies.

Acupuncture: Mixed results were found in three RCTs. While some studies showed significant BP reduction, others did not find a difference between real and sham treatments.

Conclusion

These CAM interventions can be considered for all hypertensive patients, particularly those with an interest in CAM. The best evidence exists for dark chocolate, coenzyme Q10, Qigong, slow breathing techniques, and meditation, with systematic reviews supporting their use. Vitamin D deficiency treatment and melatonin also show promise but require further research. Acupuncture results are mixed but indicate some potential benefit. More funding for large-scale trials of these interventions is needed to strengthen the evidence base.