By the way, doctor: Ginkgo biloba and dementia

Q. Some years ago, you published an article saying that ginkgo biloba might slow down dementia. I was 59, and I started taking it. I think it has helped me and know others who think likewise. But I read that a recent study says it doesn't help. Your thoughts?

A. Ginkgo biloba — or just ginkgo, for short — is an herbal supplement made from the fan-shaped leaves from the tree of the same name. Ginkgo trees — maidenhair is another name — are native to China, but they can now be found all over the world, including the United States.