Ginkgo: This ancient herb may improve memory and (surprise) wake up your sex life. 

If someone you love has Alzheimer's disease, or you want to do everything possible to keep yourself out of its grip, you'll want to know about ginkgo, an ancient herb with a promising future. In China, ginkgo seeds have been used as both food and medicine for thousands of years, but the tree's dried green leaves are the source of the herbal medicine that's making headlines today. 

A study published in the Journal of the American Medical Association (Oct. 22/29,1997) confirmed what 20 years of European research has suggested. People who take ginkgo for mild to severe dementia may improve their ability to think and interact with others. 

And for people who have cognitive deficiency, a condition caused by inadequate blood flow and nerve damage in the brain, ginkgo biloba extract (GBE) can make a marked improvement in a host of disorienting symptoms such as dizziness, ringing in the ears, headache, memory loss, concentration problems, and confusion. 

Here's more good news: Ginkgo can help ease the pain that walking causes for people who have poor circulation in their legs, a condition doctors call intermittent claudication. And there's even mounting evidence to suggest that ginkgo can put back the zing in the sex lives of men whose erections are affected by taking antidepressants. 

There are no long-term studies that prove that taking GBE now will prevent Alzheimer's disease or other forms of senile dementia later; such studies would be prohibitively expensive to carry out. But I have neighbors in their 60s who take it regularly and swear by it; they tell me GBE improves their memory Since there are no known health risks associated with long-term use of GBE, it's safe to take. The only risk involved is the one to your wallet; good GBE products are relatively expensive. 

But don't buy ginkgo as a "smart pill" that improves your intelligence. There's little scientific evidence to show that the herb produces significant benefits for the normal human brain. Sorry about that! 

How Does Ginkgo Work? 
Often with herbs, you can't point to any single compound or mechanism. What we do know is that ginkgo's flavonoids reduce harmful brain effects by preventing the activity of enzymes that produce damaging free radicals. (Substances that damage cells through oxidation.) As antioxidants, flavonoids also scavenge any free radicals that have already been formed. 

Finally, terpene derivatives in ginkgo act as bodyguards for the brain,  protecting it from blood clots and nerve damage, and increasing circulation to the brain. 

GINKO AT A GLANCE 

• Common names: Ginkgo, maidenhair tree
• Scientific name: Ginkgo biloba
• Benefits: Treatment of dementia caused by cognitive deficiency; also intermittent claudication and possibly antidepressant-induced impotence.
• Possible side effects: Stomach upset, headache, allergy; may prolong blood clotting time
• Herbal oddity: Ginkgo seeds have been used for centuries by the Chinese as food and medicine. Ginkgo leaf extract, the modern botanical product, was developed in Europe some 30 years ago.

Unlike synthetic drugs, such as tacrine, commonly prescribed for treatment of dementia, ginkgo is relatively free of side effects. Less than 2% of 10,632 people treated with ginkgo reported problems such as mild stomach upsets, headaches, or allergic reactions. 

How Much to Take 
Take 120 to 240 milligrams (mg) GBE in two or three separate doses. It works slowly; plan to take GBF for at least eight weeks before you see an improvement. There are no known contraindications to ginkgo, but use it with caution if you're taking anticoagulant herbs (such as garlic, ginger, or feverfew) or a synthetic drug such as warfarin. 

What to Buy 
Look for ginkgo products whose labels say "24/6," which means the product has been concentrated and contains 24% flavone glycosides and 6% terpenes. 

What to Avoid 
Ginkgo is an expensive herb. Standard 40 to 60 mg tablets typically sell for around $12 for 30 tablets, depending on the brand. Don't buy bargain herbs that sometimes sell for $1 or $2 for the same quantity. There's no guarantee of quality with any herb, but I especially suspect cheap ones. 

Avoid using unprocessed ginkgo leaves in any form, including teas; they contain several potent allergens known as ginkgolic acids. These compounds, removed during the processing of GBF, are kissing cousins to urushiol, the chemical that puts the itch in poison ivy. 

Taking Herbs? Tell Your Doctor 
And be sure to mention this book-Rational Phytotherapy: A Physicians' Guide to Herbal Medicine by Volker Schulz, Rudolf Hansel, and Varro E. Tyler, PhD, ScD (Springer-Verlag, New York, 1997). With results from and commentary on hundreds of European clinical studies of many popular herbs, it's a one-stop shop for interested physicians. 

QUICK TIPS 

• Give GINKO time:  Like other herbal medicines, ginko works slowly. Plan to take it for at least eight weeks before you see an improvement.
• Look for products whose labels say “24/6” or “27/7”. Don’t be taken in by bargain prices. A quality supplement should run about $12 per 30 tablet supply.