What is wormwood as a dietary supplement?

Overview

Artemisia absinthium, or common wormwood, is best known as an
ingredient of the alcoholic beverage absinthe. Wormwood is also found in
vermouth, but at lower levels. Besides its common function as a flavoring,
wormwood also has a long history of medicinal use. A reputed ability to kill
intestinal worms gave rise to the herb’s name. Other traditional uses include
treating liver problems, joint pain, digestive discomfort, loss of appetite,
insomnia, epilepsy, and menstrual problems. The leaves and flowers, and the
essential
oil extracted from them, are the parts used medicinally.
Common wormwood is a relative of sweet wormwood (A. annua), a
source of the malaria drug artemisinin (also called
artemesin).

Uses and Applications

Wormwood is sometimes recommended for the treatment of digestive conditions such
as intestinal parasites, dyspepsia, esophageal reflux, and irritable bowel
syndrome. However, there is no meaningful evidence to indicate that it is
effective for any of these conditions. Only double-blind,
placebo-controlled studies can show a treatment effective,
and only one has been performed using wormwood. This ten-week study conducted in
Germany evaluated the potential benefits of wormwood for the treatment of people
with Crohn’s
disease, an inflammatory condition of the intestines. All
forty people enrolled in the study had achieved good control of their symptoms
through the use of steroids and other medications. One-half were given an herbal
blend containing wormwood (500 milligrams [mg] three times daily), while the other
one-half were given an identical-appearing placebo. Researchers and study
participants did not know who was receiving real treatment and who was not.
Beginning at week two, researchers began a gradual tapering down of the steroid
dosage used by participants. In subsequent weeks, most of those given placebo
showed the expected worsening of symptoms that the reduction of drug dosage would
be expected to cause. In contrast, most of those persons receiving wormwood showed
a gradual improvement of symptoms. No serious side effects were attributed to
wormwood in this study.

These findings are extremely promising. However, many treatments that show promise
in a single study fail to hold up in subsequent independent testing. Further
research is needed to establish wormwood as a helpful treatment for Crohn’s
disease. Other proposed uses of wormwood have far weaker supporting evidence.
Preliminary indications hint that wormwood essential oil (like many other
essential oils) might have antifungal, antibacterial, and antiparasitic actions.
Note, however, that this does not mean that wormwood oil is an antibiotic.
Antibiotics are substances that can be taken internally to
kill microorganisms throughout the body. Wormwood oil, rather, has shown potential
antiseptic properties, but it also is potentially toxic. Other weak evidence hints
that an alcohol extract of wormwood might have liver-protective actions.

Dosage

In the foregoing study, wormwood was taken at a dose of 500 mg three times daily. A typical traditional dose of wormwood is three cups daily of a tea made by steeping 2.5 to 5 grams of wormwood in hot water. Wormwood essential oil should not be used. One should not attempt long-term use (more than four weeks) of any form of wormwood except under physician supervision.

Safety Issues

There are many unsolved questions about the toxicity of wormwood. When absinthe was popular in the late nineteenth and early twentieth centuries, a mental disorder known as absinthism, which involved hallucinations, tremors, vertigo, sleeplessness, and seizures, was associated with it. Wormwood contains thujone, a substance thought to be toxic to nerves when taken at high doses, and thujone has been proposed as a factor contributing to absinthism. However, the symptoms of absinthism are also consistent with mere chronic overuse of alcohol, and absinthe does not appear to contain sufficient thujone to cause harm. Furthermore, animal studies have generally failed to find significant toxicity with wormwood, even at relatively high doses.

Despite the absence of firm evidence, wormwood is still considered a potentially toxic herb, especially if taken over the long term. Wormwood essential oil, which contains thujone at much higher levels than those found in absinthe, should be avoided. Wormwood should not be used by young children, pregnant or nursing women, or people with severe liver or kidney disease.

Bibliography

Kordali, S., et al. “Screening of Chemical Composition and Antifungal and Antioxidant Activities of the Essential Oils from Three Turkish Artemisia Species.” Journal of Agricultural and Food Chemistry 53 (2005): 1408-1416.

Lachenmeier, D. W. “Wormwood (Artemisia absinthium L.): A Curious Plant with Both Neurotoxic and Neuroprotective Properties?” Journal of Ethnopharmacology 131 (2010): 224-227.

_______ et al. “Thujone: Cause of Absinthism?” Forensic Science International 158 (2006): 1-8.

Omer, B., et al. “Steroid-Sparing Effect of Wormwood (Artemisia absinthium) in Crohn’s Disease.” Phytomedicine 14 (2007): 87-95