Panax ginseng is one of only a few herbs that has a history of use as an appetite stimulant in the East. Scientific research on the topic has not only shown that ginseng may have the potential to stimulate appetite under certain conditions, but also that the saponins found in ginseng may have the ability to treat overeating in cases of obesity caused by a high-fat diet.
Study 1: Attenuation of anorexia induced by heat or surgery during sustained administration of ginsenoside Rg1 into rat third ventricle This study, performed out of Japan’s Kyushu University, tested the effect of the Ginsenoside Rg1 on the feeding behavior of rats both in a heated environment and post implantation surgery. The test rats were injected intravenously with a solution containing various amounts of Rg1, ranging from 1.0 to 8.0 mM. It was found that at concentrations of 4.0 mM and above,Rg1 was able to suppress the anorexia like effects on feeding caused by surgical procedures. In addition, the continuous infusion of Rg1 was able to restore normal levels of food consumption in rats that is normally suppressed when the temperature of their environment is increased. These results suggest that the compounds present in Panax ginseng can relieve anorexia brought about by both surgery and a heated environment. While this study does not claim that the effect will take place in cases of under eating among humans, it does coincide with the anecdotal reports of ginseng acting as an appetite stimulant.
Study 2: Weight gain reduction in mice fed Panax ginseng saponin, a pancreatic lipase inhibitor In 2007, a research group out of Israel tested the hypothesis that the bioactive saponins found in the roots of Panax ginseng had the ability to block the absorption of dietary fat in male mice. When the test mice were fed a high-fat diet in combination with ginseng derived saponins, researchers found that the mice did not experience the expected increase in body weight and plasma triacylglycerol levels. After investigating this phenomenon, it was found that the ginseng derived saponins were able to inhibit pancreatic lipase, suggesting that Panax ginseng may have anti-obesity and hypolipidemic effects.
Study 3: Effect of crude saponin of Korean red ginseng on high-fat diet-induced obesity in the rat A second study was carried out in order to test the effects of ginseng derived saponins on rats fed a high-fat diet. In the study, one group of rats was fed a high fat diet for five weeks, after which time they were classified as obese. Another group of rats were fed their standard low fat diet for the same five weeks. After the overfeeding period, both groups of rats were treated with a ginseng supplement rich in crude saponins for three weeks. It was then discovered that the introduction of crude ginseng saponins into the diet of the high-fat rat groupresulted in levels of body weight, adipose tissue, and food consumption similar to the rats fed the control diet. In addition, the hypothalamic NPY expression and blood serum leptin levels were significantly reduced in the rats fed a high-fat diet. This study supports the notion that the saponins found in the Panax ginseng plant may have potential applications in the treatment of obesity and other overeating disorders.
Study 4: Comparison of the antiobesity effects of the protopanaxadiol- and protopanaxatriol-type saponins of red ginseng A third study conducted by The Institute of Immunobiology at The Catholic University of Korea was able to find the underlying mechanisms of how the ginseng derived saponins treat obesity. Like the previously discussed study, male rats were divided into two groups, one control group and another high-fat groups. After five weeks of feeding, the high-fat group was separated into two groups and given a supplement containing either the saponinprotopanaxadiol (PD) or the saponinprotopanaxatriol (PT). After three weeks of supplementation, the rats given the ginseng derived saponins showed reduced body weight, body fat, food intake, and leptin to levels comparable to the control group rats. Further analysis revealed that the antiobesity effect of ginseng derived saponins may stem from blocking energy gain, and normalizing hypothalamic neuropeptides.
Conclusion Clearly, ginseng has the ability to positively affect appetite, at least in animal models. While human trials remain scarce, Panax ginseng should be considered by those looking for an herbal solution to their appetite related conditions.