Ginger Clinical Evidence

American Journal Physiology - Gastroinstestinal and Liver Physiology. 
Lien, H, et al. Effects of ginger on motion sickness and gastric slow-wave dysrhythmias induced by circular vection. 2003;284:G481-G489.’ Body Weight and Body Fat. 2006. 2(2):61-66. 

Topic: 
How does ginger prevent motion sickness?

Background:
Ginger has long been used to prevent motion sickness but the precise mechanisms of its action are not understood.

Study Type:
Human clinical intervention trial

Study Design:
Crossover design, double-blind, randomized, placebo-controlled. Subjects took ginger or a placebo and then underwent circular vection (which creates an illusion of movement). They rated their nausea from 0 to 3 (none to severe). Electrogastrographic readings (EEG) measured electrical signals in the subjects’ stomach muscles, and their levels of plasma vasopressin (a hormone that raises blood pressure by constricting blood vessels) were also assessed.

Subjects:
13 subjects with a history of motion sickness

Dosage:
A single dosage of 1,000 or 2,000 mg

Results:
Ginger reduced the severity of nausea, increased the time elapsed before onset of nausea, and decreased recovery time after nausea. There were also reductions in tachygastria (electrical activity in the stomach) and plasma vasopressin levels.

Conclusion:
“Ginger effectively reduces nausea, tachygastric activity, and vasopressin release induced by circular vection. In this manner, ginger may act as a novel agent in the prevention and treatment of motion sickness.” 

Journal of Pharmacology and Experimental Therapeutics. 
Gonlachanvit S, et al. Ginger reduces hyperglycemia-evoked gastric dysrhythmias in healthy humans: Possible role of endogenous prostaglandin. 2003 Dec; 307(3):1098-103. 

Topic: 
How does ginger prevent gastric dysrhythmias (irregular contractions of the stomach)?

Background:
Hyperglycemia (high blood sugar) can cause gastric dysrhythmia through the action of prostaglandins (hormone-like substances that regulate the contraction and relaxation of muscles and blood vessels). Ginger is known to treat gastric dysrhythmias, but how is this effect achieved?

Study Type:
Human clinical intervention trial

Study Design:
Double-blind, placebo-controlled. Subjects took either ginger or a placebo and then had their blood sugar elevated by a continuous infusion of glucose. Researchers also induced gastric dysrhythmias in subjects via an artificial prostaglandin substitute and compared ginger’s effect on these two kinds of dysrhythmias.

Subjects:
22 healthy subjects

Dosage:
A single dosage of 1,000 mg

Results:
Ginger significantly reduced both the hyperglycemic symptoms and tachygastria (abnormal electrical activity in the stomach) in subjects who did not receive the prostagladin substitute. However, in subjects who received the substitute, ginger did not have this effect. Researchers speculate that ginger works by preventing the production of prostaglandins and not by inhibiting their actions.

Conclusion:
“…[A]cute hyperglycemia evokes gastric slow wave dysrhythmias that are prevented by ginger root.” 

Journal of the Medical Association of Thailand. 
Nanthakomon T, and Pongrojpaw D. The efficacy of ginger in prevention of postoperative nausea and vomiting after major gynecologic surgery. 2006 Oct;89 Suppl 4:S130-6. 

Topic: 
Can ginger help women who have undergone major gynecological surgery with symptoms of nausea and vomiting?

Background:

Nausea and vomiting are common and unpleasant side effects of abdominal surgery. Can ginger help?

Study Type:
Human clinical intervention trial

Study Design:
Double-blind, randomized controlled trial. Patients took either ginger or a placebo one hour before surgery. Visual analog nausea scores (VANS) and frequency of vomiting were measured immediately following the operation and at 2, 6, 12, and 24 hours afterward.

Subjects:
120 gynecological surgery patients

Dosage:
A single dosage of 1,000 mg

Results:
In the group taking ginger, 48% of women suffered from nausea while 67% of the placebo group did — a difference of 38%. The most statistically significant differences were at 2 and 6 hours after surgery. The ginger group also vomited less frequently. There were no side effects to the treatment.

Conclusion:
“Ginger root has efficacy in prevention of nausea and vomiting after major gynecological surgery.” 

American Journal of Obstetrics and Gynecology. 
Chaiyakunapruk N, et al. The efficacy of ginger for the prevention of postoperative nausea and vomiting: a meta-analysis. 2006 Jan;194(1):95-9. 

Topic: 
Is there compelling evidence for the use of ginger to control postoperative nausea and vomiting?

Background:
Several studies have been completed on the use of ginger to alleviate nausea and vomiting after surgery. What do they show?

Study Type:
Review paper

Study Design:
Meta-analysis of randomized, placebo-controlled trials

Subjects:
363 patients from 5 studies

Dosage:
1,000 mg or higher

Results:
Ginger was found to be more effective than placebo in reducing nausea and vomiting after surgery.

Conclusion:
“Use of ginger is an effective means for reducing postoperative nausea and vomiting.” 

International Journal of Gynecological Cancer. 

Manusirivithaya S, et al. Antiemetic effect of ginger in gynecologic oncology patients receiving cisplatin. 2004 Nov-Dec;14(6):1063-9. 

Topic: 
Can ginger reduce vomiting in patients receiving chemotherapy for gynecological cancers?

Background:

Nausea and vomiting are some of the most debilitating side effects of chemotherapy. Can ginger offer relief?

Study Type:

Human clinical intervention trial

Study Design:

Randomized, double-blind crossover study. All patients received standard anti-nausea medications on the first day of chemotherapy. Patients were divided into two groups. In the active treatment group, ginger supplements were given every day for the first 5 days after chemotherapy. The control group received a placebo on the first day and metoclopramide thereafter.

Subjects:

48 gynecological cancer patients undergoing chemotherapy (43 completed).

Dosage:

1,000 mg/day for 5 days

Results:

Ginger performed as well as metoclopramide in the control of nausea and vomiting in both the acute and delayed phase. While metoclopramide had a side effect of restlessness, ginger did not.

Conclusion:

“In delayed phase, ginger and metoclopramide have no statistically significant differences in efficacy.” 

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Ginger Mechanism of Action:

Two components of ginger, gingerols and shogaols, have mild inhibitory effects on two kinds of receptors regulate sensations of nausea: M3 receptors (which cause muscle contractions that can lead to vomiting) and on serotonergic receptors (which regulate intestinal movements). Ginger enhances gastric motility to stimulate digestion. It also contains a natural calcium blocker that may lower the incidence of muscle spasms, thereby alleviating symptoms of colic and diarrhea.