What Are the Dangers of Bitter Orange?

Bitter orange is an herbal extract prepared from the bitter orange tree, scientific name Citrus aurantium. Also known as sour orange, Seville orange and Zhi shi, bitter orange is used in traditional Chinese medicine and by Amazonian rain forest tribes to cure indigestion, nausea and constipation, and as an essential oil in food and perfumes. According to the Science Daily website, bitter orange herbal supplements are used to treat heartburn, appetite loss, nasal congestion, weight loss and fungal infections. However, bitter orange contains the chemical stimulants synephrine and octopamine, which can speed up metabolism and cause potentially dangerous side effects, including elevated blood pressure and heart rate, heart attack and stroke.

Elevated Blood Pressure and Heart Rate

• Ephedra (Ephedra sinica), an ingredient in some weight-loss supplements, has been banned by the FDA (U.S. Food and Drug Administration) for its growing clinical association with strokes, heart attacks, hypertension and psychiatric problems. The synephrine in bitter orange is chemically similar to ephedrine and can potentially cause the same health problems. In a review study, Fugh-Berman and Myers from Georgetown University, Washington, noted that synephrine drastically increases blood pressure in humans, rats and dogs. Another study, "Blood pressure and heart rate effects following a single dose of bitter orange," published in The Annals of Pharmacotherapy, found a significant elevation, lasting up to five hours, in the systolic and diastolic blood pressure and heart rate of study subjects who consumed a single dose of bitter orange.

Heart Attack

• Synephrine has resulted in adverse cardiovascular reactions in some people who ingested the bitter orange supplement. The PubMed website reports the case of a 55-year-old woman without any history of cardiovascular risk who experienced an acute lateral-wall myocardial infarction or heart attack. A review of her medications indicated that for the previous year she had been consuming a weight-loss dietary supplement containing 300 mg of bitter orange. The Texas Heart Institute Journal mentions the case of a 24-year-old man who experienced an ST-segment-elevation myocardial infarction (STEMI) soon after ingesting a dietary supplement containing synephrine.

Stroke

• Synephrine has vascular-constricting properties that can potentially cause a stroke. A Mayo Clinic proceeding presents the case of a 38-year-old patient who developed an ischemic stroke coupled with memory loss and an unsteady gait after ingesting one to two capsules daily of a dietary supplement containing synephrine and caffeine, both of which were derived from bitter orange extract.