Ginkgo biloba (Ginkgo biloba)
What it is: Sometimes referred to as a "living fossil," the Ginkgo biloba tree is one of the oldest-surviving species on Earth. Because of ginkgo's reputation for improving memory and brain function, it's one of the most popular and best-studied herbs.
How it works: The beautiful, fan-shaped leaves of the ginkgo tree contain several compounds (flavonoids and terpenoids) that scientists believe are responsible for ginkgo's effects. Ginkgo's primary claim to fame: It improves blood flow to tiny blood vessels throughout the body, including those that supply oxygen and nutrients to the brain. But scientists now believe that ginkgo also aids memory and brain function by stimulating nerve-cell activity and protecting nerve cells from damage.
Hundreds of studies show that ginkgo can help reverse or delay mental deterioration in the early stages of Alzheimer's disease and other forms of dementia. In a yearlong trial, researchers found that participants who took 120 mg a day of a 40:1 ginkgo extract experienced noticeable gains in cognitive function (Journal of the American Medical Association, 1997, vol. 278, no. 16).
How to take it: A typical dose is 120 to 320 mg daily; choose products standardized to 24 percent ginkgo flavone glycosides and 6 percent terpene lactones. It generally takes three to six months of continuous use to notice results. But to maintain gingko's benefits, continue with supplementation indefinitely. Check with your health care practitioner before using ginkgo if you take prescription blood thinners.
Bacopa (Bacopa monniera)
What it is: Although it appears to be a modest little wildflower, bacopa is reverently referred to as brahmi in Ayurvedic medicine, after Brahma, the Hindu creator of the universe. Prescribed for more than 3,000 years by Ayurvedic practitioners to strengthen patients' nervous systems, bacopa recently has become popular in the West as a brain tonic and memory-enhancing herb.
How it works: Bacopa contains compounds called bacosides that improve the transmission of impulses among the brain's nerve cells. Bacopa also has antioxidant properties that help prevent the cellular damage that leads to memory loss and other cognitive lapses.
Most of the promising scientific proof for bacopa has come from laboratory research. However, in 2002, an Australian study of adults between ages 40 and 65 found that bacopa increased their ability to retain new information (Neuropsychopharmacology, 2002, vol. 27, no. 2).
How to take it: Bacopa is available in capsules, tablets, or as a powder. Potencies vary, so follow the manufacturer's suggested dose.
What it is: Found naturally in the brain, acetyl-L-carnitine (also called ALC or ALCAR) is a molecule that helps transport fats into the mitochondria?the "energy factories" in all cells. Dietary sources of ALC include protein-rich foods from animals, such as meat, fish, and dairy products; however, it's difficult to "eat" a therapeutic dose.
How it works: Research shows that ALC increases energy within the mitochondria and improves the activity of brain neurotransmitters, the chemicals that allow cells to communicate with one another. ALC also has powerful antioxidant properties and increases cellular levels of glutathione, the body's natural and most potent free radical scavenger.
Evidence from laboratory studies has been positive. In a recent study, scientists found that the antioxidant properties of ALCAR helped protect against the damaging effects of beta-amyloid in the brain. Beta-amyloid is a sticky protein that forms plaques in brain tissue and is found in people with Alzheimer's disease (Journal of Neuroscience Research, 2006, vol. 84, no. 2).
How to take it: Take 500 to 1,000 mg of ALC twice daily on an empty stomach.
Herbalist and author Laurel Vukovic lives in Ashland, Oregon, and has published nine books, including Herbal Healing Secrets for Women (Prentice Hall, 2000).