Ginseng - Scientific Background
The functioning of ginseng as an adaptogen, or tonic, may differ from one person to another or among populations of people included in studies.
In animal studies, ginseng increases resistance to stress.
Some animal studies of ginseng do not report increased endurance (Lewis et al 1983), whereas others do (Wang and Lee 1998). Tyler (1994) summarizes by suggesting that hundreds of small-animal experiments have shown beneficial effects of ginseng extracts, such as prolonged swimming time, prevention of stress-induced ulcers, enhanced liver function, increased immune system activity, reduced blood clotting, and many others.
Limited human studies suggest fewer cancers in ginseng users.
Many older studies of the effects of ginseng in humans are of limited quality by today's standards. Two observational studies (Yun and Choi 1995\ 1998) recently conducted in Korea report significantly fewer cases of cancer among ginseng users.
Ginseng might enhance human physical and mental performance.
Randomized, controlled trials in North America and Western Europe have not shown a consistent performance-enhancing effect (Thommessen and Laake 1996; Engels and Wirth 1997; Pieralisi et al 1991). Ongoing research with standardized extracts of ginseng may clarify its mechanisms of action and clinical effects (Gillis 1997).
Ginseng enhances immune function.
Laboratory studies (Kim et al 1998; See et al 1997), animal studies (Yun et al 1993; Yang and Yu, 1990; Kim et al 1990), and research in humans (Scaglione et al 1996) suggest that ginseng extracts enhance immune function, especially through stimulation of the activity of natural killer (NK) cells. These cells are an important first-line defense against infections and the development of cancers.
