Years ago, a friend of mine lost her grandfather. He was 82-years-old and had been living in an assisted-living facility following a mild stroke. While he bounced back physically after the stroke, his cognitive abilities were never the same.

Sure -- he could tell you all about his childhood growing up on the Jersey Shore. He could tell you about going to Harvard Law School and his travels across Europe and the Middle East. He could tell you all about the speeches he wrote for J. Edgar Hoover and President Kennedy. But he couldn't remember what day it was or what he'd eaten for breakfast.

All of us have probably been touched in one way or another by a loved one or a friend suffering from dementia. It's an increasingly tragic problem. At age 65, only 5 to 10 percent of adults are affected by dementia. But that number gets worse as we age. According to some reports, nearly half of all men and women in their 80s have some type of dementia.

But a new study out this month gives us all reason to hope that it's possible to prevent cognitive decline with extracts from a traditional Chinese plant that's been used for centuries to boost the immune system and promote longevity.

Learning from China
Chinese (or Korean) ginseng is generally considered an "adaptogen" plant that can boost your overall health. It's known to help lower blood sugar, control high blood pressure, and even treat erectile dysfunction. In the west, ginseng's most commonly used as an energy booster. You'll find it in lots of so-called "energy" drinks on the market.

But just how versatile is ginseng? Can it actually improve your memory, or prevent dementia? Well, some very promising studies are starting to emerge that may encourage you to take a second look at this well-known Chinese plant extract.

Improving stroke-induced dementia
A few years back a small, but solid study was presented at American Stroke Association's 28th International Stroke Conference. This study showed that ginseng can improve memory in people who have vascular dementia (stroke-induced dementia). After Alzheimer's disease, stroke is the second-leading cause of dementia.

Researchers looked at 40 patients with vascular dementia. They gave 25 patients Chinese ginseng three times a day for 12 weeks. They gave the remaining 15 patients Duxil, a prescription drug that's given to dementia patients to improve memory.

After 12 weeks, the patients from both groups took five memory and cognition tests. Overall, researchers found that patients taking ginseng significantly improved their average scores after the 12 weeks. Plus -- the ginseng group scored higher overall on memory testing than the Duxil group.

Previous laboratory studies on mice have suggested that ginseng could improve stroke-induced dementia, but this was the first study on humans shown to do the same.

Improving age-related dementia
Okay, so ginseng may benefit stroke-induced dementia patients. But age-related dementia is a far different disability. Can ginseng benefit these patients too?

Well, a new study out this month takes that question by the horns. In this study, researchers looked at how ginseng would affect mice with age-related memory decline (not stroke induced).

For eight months, mice were given 100 mg/kg of ginsenoside (an active component of ginseng). Researchers also gave a control group of mice placebo pills (or sugar pills) for comparison.

As expected, the elderly mice given the ginseng extract performed better on water mazes and step-down tests (two standard tests used to gauge memory in mice) than the control groups.

But researchers didn't stop there. They wanted to know why these mice performed better.

Turns out that the ginseng extract actually changed the mice's brains for the better. The ginseng actually increased certain types of proteins found in the brain responsible for learning and memory.

Hope for the future
I hope we'll see more studies in the near future testing ginseng on men and women with age-related memory loss. I'll keep you posted as new studies emerge. Often, because they're undertaken by Chinese researchers, these relevant studies just don't make it into the mainstream press in the U.S.

As a final note, only take Chinese ginseng under the care of a naturopath or M.D. Use caution if you have a bleeding disorder, diabetes, high blood pressure, heart disease, or hypoglycemia. Also, I wouldn't recommend it for anyone who is sensitive to caffeine, as ginseng can act as a stimulant.