Does Bitter Orange Benefit Your Health?

Seville oranges, a.k.a. bitter orange
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Bitter orange is, well, bitter—in fact, it's the type of orange most commonly used to make orange marmalade, which tends to be quite sour. In traditional medicine, bitter orange and extracts made from the fruit are used for digestive problems such as nausea, constipation, and indigestion.

These days, bitter orange oils, extracts, and supplements are used for heartburn, congestion, weight loss, and even to treat certain fungal infections like athlete's foot. However, there's not much evidence that these work, and there's reason to exercise considerable caution with bitter orange.

Purported Health Benefits of Bitter Orange

Bitter orange, Citrus aurantium, is a type of sour orange hybrid that's a close relative of both mandarin oranges and pomelos. It's grown throughout the Mediterranean (hence its alternative name "Seville orange"). In Chinese medicine, it's called zhi shi.

Despite bitter orange's use in traditional medicine, science hasn’t looked into bitter orange very much, and the studies that have been done to raise some concerns. Bitter orange is probably best studied for its potential role in weight loss, where it's commonly marketed either by itself or in a formula with other so-called "fat burners" and "metabolism boosters," such as caffeine.

The few studies that have been completed indicate that people taking bitter orange extract, either by itself or in a formula incorporating other ingredients, do see an increase in their metabolisms and may lose a bit of weight. However, the evidence here is limited, and there are strong reasons to be careful about using bitter orange supplements.

Bitter Orange Oil for Fungal Infections

One older study tested the use of bitter orange oil for fungal infections. That study did show good results—virtually all of those who started the trial saw their infection resolved, and side effects were minimal, involving mostly irritation of the skin with the least diluted form of the oil. The researchers in the study concluded that bitter orange is a promising and inexpensive way to fight fungal infections. No further studies have been identified.

Bitter Orange and Aromatherapy

Bitter orange is used in aromatherapy. Bitter orange essential oils smell like, well, oranges. The fun part of bitter orange is that oils from the leaves (called petitgrain) and oils from the flowers (called neroli) have distinctly different scents, but are both recognizable as “oranges.” In aromatherapy, bitter orange is used to provide a scent that stimulates and awakens (think orange juice in the morning).

Safety Concerns for Bitter Orange Supplements

Bitter orange contains a substance called synephrine, which is similar to ephedra. Ephedra was all the rage for a while because of its weight loss effects, but the U.S. Food and Drug Administration banned ephedra because of serious health concerns.

Specifically, ephedra raises the blood pressure (thereby increasing the risk of heart attacks and stroke). It is unclear whether synephrine does the same thing, although studies have shown that it may raise your heart rate (and possibly your blood pressure). Significantly, the National Collegiate Athletic Association (NCAA) placed synephrine (bitter orange) on its current list of banned drugs.

When using bitter orange on your skin (as you would fight a fungal infection), it may make you more susceptible to sunburn. Finally, people taking medications should avoid bitter orange supplements because the supplements may raise blood pressure and affect health in other ways.

In short, it is best to avoid taking bitter orange or putting it on your skin. Smelling bitter orange oils seems to be safe.

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