Ginseng is the most famous Chinese herb. It is the most widely recognized plant used in traditional medicine. Various forms of ginseng have been used in medicine for more than 7000 years. Several species grow around the world, and though some are preferred for specific benefits, all are considered to have similar properties as an effective general rejuvenator.
The name panax is derived from the Greek word panacea meaning, "all healing" and the benefits of ginseng are recognized as such. Ginseng is commonly used as an adaptogen, meaning it normalizes physical functioning depending on what the individual needs (for example, it will lower high blood pressure, but raise low blood pressure).
It is also used to reduce the effects of stress, improve performance, boost energy levels, enhance memory, and stimulate the immune system. Oriental medicine has deemed ginseng a necessary element in all their best prescriptions, and regards it as prevention and a cure. It is said to remove both mental and bodily fatigue, cure pulmonary complaints, dissolve tumors and reduce the effects of age.
Ginseng is native to China, Russia, North Korea, Japan, and some areas of North America. It was first cultivated in the United States in the late 1800's. It is difficult to grow and takes 4-6 years to become mature enough to harvest. The roots are called Jin-chen, meaning 'like a man,' in reference to their resemblance to the shape of the human body.
Native North Americans considered it one of their most sacred herbs and add it to many herbal formulas to make them more potent. The roots can live for over 100 years.
Ginseng contains vitamins A, B-6 and the mineral Zinc, which aids in the production of thymic hormones, necessary for the functioning of the defense system. The main active ingredients of ginseng are the more than 25 saponin triterpenoid glycosides called "ginsenosides". These steroid-like ingredients provide the adaptogenic properties that enable ginseng to balance and counter the effects of stress. The glycosides appear to act on the adrenal glands, helping to prevent adrenal hypertrophy and excess corticosteroid production in response to physical, chemical or biological stress.
Studies done in China showed that ginsenosides also increase protein synthesis and activity of neurotransmitters in the brain. Ginseng is used to restore memory, and enhance concentration and cognitive abilities, which may be impaired by improper blood supply to the brain.
Ginseng helps to maintain excellent body functions. Siberian ginseng has been shown to increase energy, stamina, and help the body resist viral infections and environmental toxins. Research has shown specific effects that support the central nervous system, liver function, lung function and circulatory system.
Animal studies have shown that ginseng extracts stimulate the production of interferons, increase natural killer cell activity, lower cholesterol and decrease triglyceride levels. Men have used the herb to improve sexual function and remedy impotence. Ginseng is believed to increase estrogen levels in women and is used to treat menopausal symptoms.
It is also used for diabetes, radiation and chemotherapy protection, colds, chest problems, to aid in sleep, and to stimulate the appetite.
Ginseng is widely used in the U.S. as a dietary supplement by consumers seeking to improve general energy and vitality, particularly during times of fatigue or stress. Other reported uses of ginseng include normalizing blood sugars, such as in diabetes, stimulating immune function, and treating male impotence. Biologically, ginseng has been shown to allow cells to more readily use stored sugar, enabling red blood cells to carry more oxygen.
Ginseng has long been revered by practitioners of Eastern medicine as an effective treatment for numerous health conditions. Western researchers are beginning to unravel the specific benefits of the herb, including new findings that show American ginseng (Panax quinquefolius) to be an effective blood-glucose modulator. Researchers have suggested that ginseng exhibits a hypoglycemic effect in animals, and new human trials are validating the claim.
Three new studies, performed jointly by researchers at the University of Toronto, St. Michael's Hospital in Toronto and the University of Ottawa, show that American ginseng can lower blood-sugar levels in diabetic and nondiabetic patients.
In the first study, researchers gave nine subjects with type II diabetes and 10 nondiabetic subjects either 3g American ginseng or placebo, followed by a 25g oral glucose solution. Both ginseng groups experienced an 18 percent to 22 percent reduction in postprandial glycemia (blood-sugar levels after carbohydrate consumption) compared with placebo. In the nondiabetic subjects, ginseng lowered postprandial blood sugar only when taken 40 minutes prior to the glucose challenge. In diabetic subjects, ginseng lowered postprandial sugar whether administered 40 minutes prior to, or together with, the glucose challenge.
In the second study, researchers compared different doses of American ginseng—3, 6 and 9 g—in diabetic subjects. They found that ginseng caused the same postprandial blood-sugar lowering results at each dose, and at any time from 0 to 120 minutes before the glucose challenge.
Researchers in the third study aimed to replicate the first two studies' results using a lower ginseng dose in nondiabetic patients. Twelve healthy individuals received 1, 2 or 3 g American ginseng or placebo at 40, 20 or 10 minutes before or along with a glucose challenge. They found no significant differences between the three doses and observed an average lowering of postprandial glucose levels of 11.4 percent. As in the first study, ginseng was effective only when taken 40 minutes prior to the glucose challenge.
The somewhat disparate results of these three studies can be summarized as follows: In both healthy and diabetic people, doses as small as 1 g American ginseng can lower the glycemic response after carbohydrate consumption. Although administration time does not seem to be an issue for diabetics, ginseng regulates glycemia in healthy people most effectively when taken 40 minutes prior to carbohydrate consumption.
The results of these studies are important because of mounting evidence that postprandial hyperglycemia poses a significant health risk to both diabetic and nondiabetic people. Poor control of postprandial glucose levels is a diabetic risk factor for developing vascular complications, such as atherosclerosis, and researchers have found that nondiabetics with higher postprandial blood-sugar levels were more likely to develop diabetes and to die of cardiovascular disease.
Questions remain as to the mechanisms behind ginseng's hypoglycemic action. The Toronto researchers concluded from animal experiments that ginseng slows digestion, stimulates insulin secretion and enhances nitric oxide-mediated uptake of glucose into cells. Each of these mechanisms offers a plausible explanation for ginseng's ability to lower blood-glucose levels, although the latter two mechanisms may better explain why ginseng works in nondiabetics when taken 40 minutes prior to a glucose challenge.
Emerging Alternative Therapies for Type 2 Diabetes
Ginseng has been used in Chinese traditional medicine for 3,000 years and is currently very popular as a dietary supplement. While health claims for ginseng include curative, aphrodisiac, and restorative properties, few human studies have been done to test these claims. In vitro and animal studies have suggested that ginseng may have therapeutic effects on diabetes; ginseng has lowered blood glucose in rodents. The only long-term human study of ginseng and diabetes found that long-term glycemic control improved with ginseng supplementation (200 mg ginseng extract/day for 8 weeks). However, the type of ginseng extract was not specified and the results may have been confounded because the subjects also experienced significant weight loss.
The authors tested the effects of American ginseng (Panax quinquefolius) on postprandial glucose metabolism in persons with and without type 2 diabetes. The ginseng was given in doses ranging from I to nine grams before an oral glucose challenge. In the diabetics, doses of three, six, and nine grams were equally effective in lowering postprandial glucose, which was 15-20% lower compared with placebo. The safety profile was very good, and the data suggest that ginseng might effectively augment conventional treatment for type 2 diabetes.
The authors also conducted a long-term, placebo-controlled, double blind, crossover study with 24 type 2 diabetics. The patients were randomly assigned to take either placebo or one gram standardized American ginseng extract before meals (three times/day) for eight weeks. Significant reductions in fasting blood glucose and hemoglobin A1c (an indicator of long-term glycemic control) occurred when patients took the ginseng. Blood pressure also dropped during ginseng treatment; this was unexpected, as many previous studies linked ginseng to increased blood pressure. The authors concluded, "That an American ginseng extract added to the conventional treatment of diabetes significantly improved glycemic and blood pressure control beyond conventional treatment alone."