What Is Bitter Orange and Why Is It Used?
Bitter orange, scientifically known as Citrus aurantium, is a fruit-bearing tree native to Southeast Asia, now grown in many parts of the world. The fruit, peel, flowers, and leaves have been used for centuries in traditional medicine for various ailments, including digestive issues. Today, bitter orange extract is primarily known for its use in dietary supplements, particularly those marketed for weight loss and athletic performance.
The reason for its popularity as a supplement ingredient stems from the presence of a chemical compound called synephrine. Synephrine is structurally similar to ephedrine, a substance banned by the U.S. Food and Drug Administration (FDA) in 2004 due to serious heart-related side effects. Because of this similarity, supplement manufacturers began using bitter orange and synephrine as an "ephedra-free" alternative.
The Cardiovascular Risks of Bitter Orange Supplements
While bitter orange is generally considered safe when consumed in the small amounts found in food, the concentrated extracts in supplements pose a significant risk, particularly to the cardiovascular system. Synephrine acts as a stimulant, which can constrict blood vessels, increase blood pressure, and raise heart rate. These effects are exacerbated when bitter orange is combined with other stimulants, especially caffeine.
There have been several case reports of serious cardiovascular events associated with bitter orange use, including:
- Heart attacks
- Strokes
- Abnormal heart rhythms (arrhythmia)
- High blood pressure (hypertension)
- Fainting
It is often difficult to isolate bitter orange as the sole cause of these events, as many supplements contain multiple ingredients. However, the known stimulant effects of synephrine are a major cause for concern, especially for individuals with pre-existing heart conditions or high blood pressure.
Potential Drug Interactions
Another critical safety aspect of bitter orange involves its interaction with various medications. Bitter orange can inhibit certain liver enzymes, such as cytochrome P450 (CYP) 3A4, which are responsible for metabolizing numerous drugs. This can increase the levels of these drugs in the bloodstream, leading to enhanced effects or more severe side effects.
Bitter orange is known to interact with:
- MAOIs (Monoamine Oxidase Inhibitors): Used for depression, these drugs combined with bitter orange can cause dangerously high blood pressure.
- Stimulant drugs: Combining bitter orange with other stimulants (like those for ADHD or decongestants) can dangerously amplify effects on heart rate and blood pressure.
- Calcium channel blockers (e.g., Felodipine): Bitter orange juice can significantly increase the drug's concentration in the blood.
- HIV/AIDS medication (e.g., Indinavir): Bitter orange can slow the metabolism of these drugs, increasing their effects.
- Diabetes medication: There is some evidence bitter orange may affect blood sugar control, potentially causing levels to drop too low.
Safety Comparison: Food vs. Supplement
| Feature | Bitter Orange in Food (e.g., Marmalade) | Bitter Orange in Supplements (Extract) |
|---|---|---|
| Processing | Minimally processed; compounds are less concentrated. | Concentrated extract of the fruit or peel to standardize synephrine content. |
| Synephrine Level | Generally very low and not clinically significant. | High concentration, often combined with other stimulants like caffeine. |
| Safety Profile | Likely safe for most people in typical dietary amounts. | Possibly unsafe due to high stimulant concentration and cardiovascular effects. |
| Regulatory Status | Considered 'Generally Recognized As Safe' (GRAS) for food flavoring. | Largely unregulated, leading to inconsistent and sometimes dangerous products. |
| Drug Interactions | Lower risk; interactions are more commonly linked to bitter orange juice. | High risk, especially when combined with other stimulants or medications. |
Who Should Avoid Bitter Orange?
Certain populations are at a much higher risk of adverse effects from bitter orange and should avoid it entirely:
- Individuals with heart conditions: Anyone with a history of heart disease, high blood pressure, or irregular heart rhythms should not take bitter orange supplements.
- Those taking certain medications: As detailed above, people on MAOIs, stimulants, blood pressure medication, or other CYP3A4-metabolized drugs are at risk.
- Pregnant and breastfeeding women: Due to insufficient safety data, bitter orange should be avoided during pregnancy and lactation.
- Individuals with glaucoma: Bitter orange may worsen this condition.
- People with diabetes: Bitter orange may interfere with blood sugar control.
- Anyone undergoing surgery: Bitter orange can affect heart rate and blood pressure, so it should be stopped at least two weeks before a scheduled procedure.
The Unreliable Nature of Supplements
One of the biggest concerns with bitter orange supplements is the lack of regulation. An FDA analysis of bitter orange supplements found significant inconsistencies between labeled and actual synephrine content. Some products even contained synthetic amines that are illegal in the United States. This makes it nearly impossible for a consumer to know exactly what they are taking and in what dosage, increasing the risk of harm.
Conclusion: Caution Is Key
Is bitter orange safe? When consumed in the small amounts found in foods like marmalades, it is generally considered safe for most healthy people. However, the use of concentrated bitter orange extracts in dietary supplements is a completely different matter. The potential for serious cardiovascular side effects, especially when combined with other stimulants like caffeine, and the risk of dangerous drug interactions, makes it a substance that requires extreme caution. The unreliability of supplement labeling further compounds these risks. If you are considering a supplement containing bitter orange, the safest course of action is to consult a healthcare professional. For those with pre-existing conditions or on certain medications, avoiding it altogether is the wisest choice.
Learn more about supplement regulation and safety from the National Center for Complementary and Integrative Health.
