COLUMN:

The Truth About Ginkgo Biloba,
St. John’s Wort
and Kava

For many seniors, herbal medicines seem like a good idea for certain common complaints such as memory loss, depression and anxiety. However, some herbs have toxic side effects or can produce adverse reactions when taken with prescription medications. Medical doctors seldom have adequate training in botanical medicines, so as a rule they aren’t equipped to answer seniors’ questions about them. And wading through research on herbal medicines can be time-consuming and confusing.

Many of my senior patients want to know more about ginkgo biloba, St. John’s wort and kava, which have all been studied extensively. Each has its pros and cons.

Ginkgo biloba has been used in traditional Chinese medicine for more than 5,000 years, and it is one of the best-selling herbal medicines in Europe for the treatment of dementia. Studies have shown that ginkgo leaves contain antioxidants called flavonoids and terpenoids. They scavenge free radicals, preventing them from damaging cells. The flavonoids also regulate the elasticity and tone of blood vessels and can inhibit the stickiness of platelets, preventing strokes.

In addition, ginkgo biloba is used to enhance circulation throughout the body. In Germany, the Commission E (the equivalent of the FDA in the United States) has approved the use of ginkgo biloba for the treatment of poor memory, depression, ringing in the ears (tinnitus), dizziness and headaches. Clinical studies have shown that ginkgo biloba may be helpful in preventing the progression of Alzheimer’s disease.

Although ginkgo biloba is considered to be a safe herb with relatively few side effects, in some cases people who have taken the herb have experienced stomach upset, headaches, skin rashes or dizziness. It is advisable to avoid taking ginkgo biloba if you are on the following drugs, due to potential drug-herb interactions: anticonvulsant medications, blood-thinning medications, monoamine oxidase inhibitors (MAOIs) such as the antidepressant medications phenelzine and tranylcypromine, thiazide diuretics and the antidepressant medication trazadone.

If you are on any medication, consult your physician before taking ginkgo biloba. The recommended dose is 40 milligrams (as a standardized extract of 24 percent ginkgo flavonglycosides and 6 percent terpene lactones) three times a day.

St. John’s wort is an herb known worldwide for its ability to help people who suffer from depression, a condition that affects more than 19 million Americans. There are many different forms of depression; the type of depression that St. John’s wort can help, according to a large study published in the British Medical Journal in 1996, is mild to moderate depression.

The active ingredients in St. John’s wort include hypericin and hyperforin, which are thought to affect the brain chemical serotonin. Many antidepressant medications work by enhancing the level of serotonin in the body, and St. John’s wort may work by inhibiting the reabsorption of serotonin at nerve cells. People often take St. John’s wort because its effects are milder than those of prescription antidepressant medications.

One of the biggest concerns about taking St. John’s wort is that the herb can have adverse reactions when taken in conjunction with a number of prescription medications. These include drugs used to control HIV infection such as indinavir, antidepressant medications, chemotherapeutic drugs such as irinotecan and drugs used to prevent rejection of organ transplants such as cyclosporine. The herb also may reduce the effectiveness of birth control pills and some pain medications. Among the potential side effects of St. John’s wort are dry mouth, diarrhea, nausea, dizziness, fatigue and increased sensitivity to sunlight.

St. John’s wort can be effective and safe when used correctly, but it is advisable to consult your physician before you begin taking it. It is best purchased as a standardized extract containing .3 percent hypericin, and the recommended dose is 300 milligrams three times a day.

Kava has a long history of use by people of the South Pacific. In the West, it has become a popular herbal medicine due to its ability to treat anxiety without interfering with mental clarity. Kava contains kavalactones that have been shown to have an effect on the limbic system (the part of the brain that influences emotional processes), and it also may enhance the binding of GABA, the calming brain chemical, to nerve receptors.

A few years ago, a number of cases of liver toxicity were reported after people consumed kava, and as a result the herb was banned in some European countries. These cases were perplexing to researchers, considering that the Polynesians used kava safely for thousands of years.

It appears that the way the kava was prepared in the European products was very different from the time-honored methods. Instead of using a traditional water extract, the European products were extracted using acetone and ethanol, which resulted in a higher level of toxic compounds in the finished products.

In addition, many of the people who experienced liver toxicity after taking kava were also on prescription medications. Kava should not be taken at the same time as alcohol, antidepressant medications, tranquilizers, psychiatric drugs (such as antipsychotics or buspirone) or drugs that affect the liver such as acetaminophen (e.g., Tylenol). People who have Parkinson’s disease should not take kava. Side effects of taking excessive amounts of kava include skin rash, upset stomach and drowsiness.

The recommended dose for treating anxiety is 45 to 70 milligrams of kavalactones three times a day. This dose should not be exceeded, and kava should not be taken for more than four weeks.

Ginkgo biloba, St. John’s wort and kava have a lengthy and impressive record of clinical effectiveness in treating a number of ailments that affect many seniors. However, they should be used only under the guidance of a licensed naturopathic physician who has had extensive training in prescribing them. You also should let your medical doctor know what herbal remedies you are taking before going on any prescription medications.

Dr. Laurie Steelsmith is a licensed naturopathic physician and acupuncturist in Honolulu and author of the best-selling book Natural Choices for Women’s Health published by Random House. You can reach her at 943-0330 or via the Web site www.drsteelsmith.com. This column provides general medical information only; it is not intended to replace recommendations you would receive from your doctor after undergoing a thorough physical examination.

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