Supplements derived from foods may sound harmless--after all, you probably eat some of those foods--yet they can contain chemicals with the potential for adverse side effects. Taking products containing bitter orange extract, derived from the peel of the bitter orange, may result in undesirable side effects. If you are considering taking a bitter orange product, consult with a doctor first.
Horticultural Information
Bitter orange (Citrus aurantium) is also known as sour orange or Seville orange. It's commonly used as a rootstock for grafting sweet orange trees. While the fruit isn't really eaten out of hand like a sweet orange, it is the main type of orange used for British marmalade, and parts of the plant and fruit also serve as flavorings for items like candy and soda. The flowers of the tree provide neroli oil, and the suds-producing fruit is a traditional soap for clothes and hair in the Pacific, says Purdue University. The tree is native to Asia and came to the Western Hemisphere in the 1500s. Few places cultivate it compared to sweet oranges.
Uses
Bitter orange extract's most-studied use is in weight loss supplements. One of its components is synephrine, a chemical that mimics the effects of ephedra, which the Food and Drug Administration banned in 2004. Bitter orange may have antifungal effects, and the National Center for Complementary and Alternative Medicine says another use of bitter orange is in treatments for the fungi that cause athlete's foot and ringworm. Drugs.com adds that bitter orange has several other possible uses, including lowering cholesterol and acting as an anti-inflammatory agent, but the site also notes there is little data confirming these effects.
Considerations
The synephrine in bitter orange is a sympathomimetic chemical that is similar to ephedra. This has lead to studies of synephrine's safety and possibly related cardiovascular problems. Drugs.com lists five examples of adverse cardiovascular effects and one case of muscular effects from taking supplements containing synephrine and bitter orange. These include ischemic stroke, tachycardia, angina, two heart attacks and rhabdomyolysis. At least one of these cases occurred after only one week of use by an apparently healthy individual. A 2005 article in the journal "Mayo Clinic Proceedings" that described the ischemic stroke case, in which a 38-year-old man had taken a synephrine and caffeine supplement for one week, reported he took no other medications and had no other significant medical history.
Interactions and Warnings
Bitter orange may interact with several other medications and supplements including vasoconstrictors, anxiolytics, antivirals, caffeine, calcium-channel blockers and other weight loss products. Do not use products containing bitter orange if you have high blood pressure, glaucoma, any heart condition or depression, or if you are pregnant. The NCCAM says topical products containing bitter orange may allow your skin to burn faster, especially if you are fair-skinned.
Synephrine in Food
Bitter oranges are used in flavorings and foods such as traditional marmalade, so anyone eating these foods is ingesting synephrine. However, Mark Blumenthal of the American Botanical Council wrote in 2004 that the level of synephrine in bitter orange marmalade was extremely low, only about 0.01 percent. Synephrine is also present in other citrus such as tangerines, and Blumenthal notes this implies that people are getting more synephrine in their diet than they realize. However, he also writes that food products containing bitter orange, and thus synephrine, are usually considered safe by the Food and Drug Administration because of the low levels present. Higher levels are not considered safe.
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