Kava is often prescribed to treat stiffness, insomnia, pain, jet lag, uncontrolled epilepsy and anxiety. Scientists have found that kava contains chemicals called kavapyrones. They reduce convulsions and enable muscle relaxation. The scientists have also found that kavapyrones cause in the brain reactions similar to the reactions cause by medications used for treatment of anxiety and depression. Unlike those medicines, the compounds found in kava do not cause negative side effects on heart rating, thinking ability, breathing and blood pressure.

Kava changes the amount of neurotransmitters in the blood because the plant stops the absorption of the neurotransmitter norepinephrine. High levels of norepinephrine in the blood can help for relaxation and can reduce anxiety. Also, kava increases the number of attachment sited for gamma aminobutyric acid (GABA) which is another neurotransmitter. The increased number of GABA sites may enhance GABA activity and this may cause sedation.

In addition, kava contains chemicals that prevent the enzyme monoamine oxidase-B (MAO-B) from affecting the level of dopamine, which is also neurotransmitter. MAO-B and dopamine have both affect the body’s emotional stability. However, the effects of kava in this direction are not very well-known.

Standardized kava extract can be taken three times per day. The total daily amount of kava should not be more than 210 mg. One dose of 210 mg can be used to treat insomnia. Doses of 2-4 g can be taken three times per day to treat stress, insomnia and anxiety.

Kava can cause liver damage, so people who suffer from liver disease and take liver-compromising medicine should consult a doctor before they take kava.

Seizure is defined as an abnormal movement or behavior due to unusual electrical activity in the brain, according to WebMD. Epilepsy is a group of related disorders characterized by a tendency for recurrent seizures.

German scientists, writing in the Journal of Natural products, said that they were convinced that the herb could have a “detrimental effect.”

“Contrary to our own previous assumption, we are now convinced, however, that G. biloba medications and other products can have a detrimental effect on a person’s health condition,” they said.

“It is therefore important that the large number of G. biloba product users and their health care providers be made aware of these risks, in order to enable them to make informed decisions about the use of these preparations.”

Review of past research
To reach this conclusion, researchers Eckhard Leistner and Christel Drewke from the University of Bonn reviewed previously done scientific research on gingko and found 10 reports of seizures linked to the herb.

The researchers noted that people use pills, tea, and other products prepared from the leaves of Gingko tree as a remedy for treating a wide range of health problems such as depression [a mental state characterized by a pessimistic sense of inadequacy and a despondent lack of activity] , memory loss, dizziness, headaches, alcohol abuse, blockage in blood vessels etc.

For the study, they particularly focused on one chemical compound in the herb, a potentially toxic material called gingkotoxin.

Gingko biloba linked to seizures
Evidence from the laboratory studies found that gingkotoxin might alter the chemical signaling pathways in the body in a way that it triggers epileptic seizures.

Further evidences suggest that the herb may also interfere with the effectiveness of anti-seizure medications.

The researchers noted that gingko biloba showed “clear potential for adverse effects,” particularly in vulnerable patients.

The study also suggests that the herb may cause harmful effects in people without the epilepsy condition, but who eat raw or roasted Ginkgo seed or drink tea prepared from Ginkgo leaves.

Experts’ advice
Although the evidence was not compelling enough to prove that the herb caused the seizures in the reported cases, the patients should be warned of the possibility and the manufacturers should re-examine the toxic level of the herb, the researchers recommended.

Professor John Duncan, from the National Society for Epilepsy, said, “We believe that some herbs, for example St John’s wort, are linked to a higher risk of seizures, but there is still not a great deal of evidence about problems related to ginkgo.

“We would say that if someone who has epilepsy wants to take this remedy, they should simply be aware of the possibility.”