
Zingiberis rhizoma, ginger root, shen jiang
Derived from the rhizome of the plant, ginger is native to Asia. It has been used as food and as medicine primarily for gastrointestinal symptoms. In vitro studies suggest that ginger has antiemetic (18), anticancer (8) (9) (10), anti-inflammatory (23), and hypoglycemic effects (23) and may protect against Alzheimer's disease (11). The antiemetic action of ginger is attributed to its constituents, shogaol and gingerol, and their interactions with 5HT-3 receptors (18).
Clinical trials indicate that ginger can effectively reduce nausea and vomiting following surgery (2) and that associated with pregnancy (3) (4) and motion sickness (6). Evidence of ginger's potential against chemotherapy-induced nausea and vomiting is generally positive (20) (21) (24) (29). Conclusions from systematic reviews suggest moderate efficacy of ginger for treating osteoarthritic and chronic low back pain (22), and its anti-inflammatory potential (26). More studies are needed to confirm these effects.
Ginger also influences gastric emptying in healthy individuals (7). It may also increase risk of adverse effect of some prescription drugs.
The antiemetic action of ginger is attributed to the shogaol and gingerol constituents found in the rhizome. They are believed to stimulate the flow of saliva, bile, and gastric secretions. Additional activities include the suppression of gastric contractions and improvement of the intestinal muscle tone and peristalsis (17). Constituents in ginger are thought to interact with 5HT-3 receptors and may be partially responsible for its antiemetic activity (18). Ginger has been shown to inhibit thromboxane formation and inhibit platelet aggregation (15); however, this effect appears dependent on dose and formulation (e.g., dried, fresh, or extract) (19). An in vitro study suggests that ginger may have therapeutic effects against Alzheimer's disease by protecting neuronal cells from beta-amyloid insult (11). Apoptosis of gastric cancer cells by gingerol is mediated through TRAIL-dependent caspase 3/7 activation while shogaol alone reduces in vivo tumor growth (8). Gingerol inhibits cell cycle progression by reducing cyclin D1 expression and induces apoptosis in colorectal cancer cells (9), and also inhibits secretion of angiogenic cytokines such as VEGF and IL-8 in ovarian cancer cells (10).
After administering 2.0 g/day ginger extracts to healthy human subjects for 24 days, their blood samples were drawn within 24 hours of the last dose. The levels of 10-gingerol sulfate, 8-gingerol glucuronide, 8-gingerol sulfate, 6-shogaol gluruconide, and 6-shogaol sulfate were below the detection limit in all the participants due to their short half-lives, between 1 and 3 h, and rapid clearance (27).
Anticoagulants / Antiplatelets: Because ginger can inhibit thromboxane formation and platelet aggregation, concomitant use with anticoagulants may increase the risk of bleeding (14).
Hypoglycemics / Insulin: Ginger may cause additive reductions in blood glucose (23).
Tacrolimus: Pre-treatment with ginger increases the plasma levels of tacrolimus (28).
Wu KL, et al. Effects of ginger on gastric emptying and motility in healthy humans. Eur J Gastroenterol Hepatol 2008;20(5):436-440.
The influence of ginger on gastric emptying and motility was assessed in this randomized, double-blind, controlled study of 24 healthy participants. Following an 8-hour fast, participants received placebo or 1200 mg of ginger. After 1 hour, participants consumed a low-nutrient soup (500 ml) following which dimensions of the antrum and fundus and antral contractions were analyzed. In participants who received ginger, antral area was reduced and contractions were more frequent. The authors suggest using more sensitive three-dimensional ultrasound or MRI to further define the exact stomach areas affected by ginger. Because this study analyzed healthy individuals, the effect of ginger on gastric emptying and motility in individuals with gastrointestinal symptoms such as dyspepsia remains unknown.
Smith C, Crowther C, Willson K, Hotham N, McMillian V. A randomized controlled trial of ginger to treat nausea and vomiting in pregnancy. Obstet Gynecol. 2004 Apr;103(4):639-45.
Two hundred and ninety-one women who were less than 16 weeks pregnant were randomly assigned to receive either 1.05 grams of ginger or 75 mg of Vitamin B6 daily for three weeks. Nausea and vomiting scores were measured weekly. Women receiving ginger had similar reductions in nausea, vomiting and retching as those receiving vitamin B6. In addition, women in both groups had similar outcomes of pregnancy suggesting that ginger is a safe and effective treatment for nausea and vomiting due to pregnancy.
Bottom Line: Ginger may help to relieve nausea and vomiting
Ginger root contains compounds that may help relieve or prevent nausea and vomiting. These substances can increase the flow of saliva and digestive juices. They may also help to calm the stomach and intestine. Scientists are still unsure exactly how ginger exerts these effects. In humans, studies have shown that eating fresh ginger (but not dried ginger) in high doses can “thin” the blood by preventing the platelets from sticking together. In addition, one laboratory study suggests that ginger can protect brain cells from the plaques that cause Alzheimer's disease, but this effect has not been studied in humans.
Nausea and vomiting during pregnancy:
To test the ability of ginger to treat pregnancy-related nausea and vomiting, researchers randomly gave 70 women early in their pregnancy (less than 17 weeks) either one gram of ginger or a placebo. All women had episodes of vomiting 24 hours prior to starting the study. After four days of therapy, women taking ginger reported significantly fewer episodes of nausea and vomiting than women taking the placebo. In addition, women taking ginger had no more problems with their pregnancies than women taking the placebo, suggesting that ginger is safe for pregnant women.
Another trial of ginger involved 291 women less than 16 weeks pregnant. The women were randomly assigned to receive either ginger or vitamin B6 (a vitamin that is known to reduce nausea and vomiting during pregnancy) daily for three weeks. Women receiving ginger had similar reduction in nausea, retching and vomiting.