Herbal remedy for nausea and vomiting Ginger

Often mislabeled as a root, ginger is technically a rhizome or underground stem of the plant Zingiber officinale Roscoe. Commercial varieties are ordinarily designated according to their geographical origin, such as African ginger, Cochin ginger, or Jamaican ginger. Used in China as a spice and

a drug for some twenty-five centuries, it is now employed throughout the world for both these purposes, but particularly as a flavoring agent. Its uses in traditional medicine are numerous, but the properties for which it has been most valued are those of a carminative or digestive aid. 1

Results of the first clinical investigation into the antinausea and antiemetic potential of ginger were published in 1982. 2 Mowrey and Clayson tested thirty-six college students with a high susceptibility to motion sickness and concluded that 940 mg of powdered ginger was superior to 100 mg of dimenhydrinate in reducing the symptoms of motion sickness

24 Tyler's herbs of choice: The therapeutic use of phytomedicinals when consumed twenty to twenty-five minutes prior to tests conducted

in a tilted rotating chair. The placebo chosen, curiously, was chickweed (Stellaria media).

The results of investigations subsequent to the initial one of Mowrey and Clayson have been quite interesting. An American group consist- ing of Stott and colleagues reported, in 1985, that ginger had no effect on

motion sickness. 3 In 1986, Swedish investigators Grøntved and Hentzer found ginger significantly better than a placebo in reducing vertigo; it did not have any effect, however, on the nystagmus (oscillation of the eyeballs)

of test subjects. 4 Then, Americans led by Wood reported negative results in 1988. 5 They noted that motion sickness is a CNS reaction to vestibular (inner ear) stimulation with only secondary gastrointestinal involvement. Because ginger lacks CNS activity, it was not, they concluded, a useful motion sickness preventive.

More recent European studies have yielded favorable results. Grøntved and colleagues tested the effects of ginger on seasickness in eighty Swedish naval cadets. 6 They concluded that ginger reduced vomiting and cold sweating. Also, fewer symptoms of nausea and vertigo were reported, but there is a question about the statistical significance of these

observations. Schmid and others 7 compared seven commonly used agents for prophylaxis of seasickness, including ginger (Zintona™, Dalidar Pharma, Israel), in the form of an extract of the rhizome, standardized to pungent phenolics; similar rates of efficacy were observed for ginger and five of the six drugs tested. Only the Scopolamine transdermal therapeu-

tic system showed a slight trend to less efficacy and more illness, causing slightly more visual problems than the other study medications.

In a randomized, double-blind trial, Riebenfeld and Borzone assessed the comparative efficacy and tolerability of Zintona and dimenhydrinate in sixty subjects (ages ten to seventy-seven) with a history of seasick-

ness sensitivity. 8 Patients were administered either 500 mg of the ginger preparation thirty minutes before embarkation, followed by 500 mg every succeeding four hours, or 100 mg dimenhydrinate thirty minutes before embarkation, followed by 100 mg every succeeding four hours, both over the forty-eight-hour duration of the treatment. Ginger was judged very effective (n = 21) or effective (n = 7) in most cases as compared to very effective (n = 15) and effective (n = 12) for dimenhydrinate.

In Germany, Holtmann and colleagues carried out tests to determine the mechanism of ginger’s positive effects. 9 They concluded that the drug does not influence the inner ear or the oculomotor system, both of which are of primary importance in motion sickness. Thus, a CNS effect of ginger should be ruled out, and it must be concluded that the antiemetic mechanism of action of ginger is of a gastrointestinal nature.

Concerning the involvement of the gastrointestinal tract, the symptoms of motion sickness are associated with an abnormal increase in pacemaker

Chapter three: Digestive system problems

25 activity in the gastric musculature, called tachygastria, resulting in disor-

dered gastric mobility. In addition, a consequence of this gastric dysrhyth- mia is a prolonged inhibition of gastric emptying. Therefore, drugs that prevent tachygastria or enhance gastric emptying may reduce the incidence and severity of motion sickness. Stewart and coworkers at Louisiana State University investigated the effects of ginger on motion sickness susceptibility and gastric function; however, even though they found that ginger partially inhibited tachygastria, it did not affect gastric emptying and

did little to relieve the symptoms of motion sickness. 10 It may be relevant to note that this study was neither double blind nor random. Two systematic reviews of randomized controlled trials (RCTs) of ginger for the prevention of nausea and vomiting have been conducted since publication of the 2nd edition of this volume. Ernst and Pittler 11 found six studies worthy of consideration; highest ranked were Grontved and others 6 and Arfeen and others 12 , results of the former positive and the latter negative. Betz and others 13 discerned as potentially relevant 24 RCTs, of 100 published reports considered; of these 24 RCTs covering 1073 patients, 16 contained information regarding activity of ginger against kinetosis, postoperative nausea and vomiting (PONV), morning sickness, and hyperemesis gravidarum. The authors of the latter study concluded that while there was no clear evidence for the efficacy of ginger in the treatment of PONV and kinetosis, the results for the treatment of nausea and vomiting in pregnancy are encouraging, and in doses of up to 6 g daily, ginger appears to produce very few side effects.

To summarize, it is interesting to note that, after the initial studies of ginger’s favorable effects on motion sickness, several additional investigations have been made to date. Half of these studies have given negative results and the other half have had positive outcomes. Factors that might explain this discrepancy include the failure to use standardized ginger preparations in the clinical trials. Ginger preparations vary widely in chemical composition and may contain inactive adulterants. Ginger grown in various areas of the world may also differ in content. It has also been well established that although there is no question about the physical basis of motion sickness, psychological factors also play an important role in suppressing as well as enhancing the tendency to be sick.

These problems should be resolved in future clinical trials by employing ginger preparations standardized in the amount of shogaols and gingerols now that they are known to be the antiemetic principles and by employing double-blind, crossover studies in the experimental design. In spite of these conflicting reports, analysis of some of the findings previously mentioned, together with other unpublished data, has been suffi- cient to convince Commission E of the German Federal Health Agency that ginger is effective not only for indigestion but also in preventing

26 Tyler's herbs of choice: The therapeutic use of phytomedicinals the symptoms of motion sickness. The commission recommends it at an

average daily dose level of 2–4 g. 14 Whatever activity ginger possesses may be attributed to a contained volatile oil (1–3 percent) responsible for its characteristic odor and oleo- resin (mixture of volatile oil and resin) responsible for its pungency. The principal components of the volatile oil are the sesquiterpene hydrocarbons zingiberene and disabolene, which are accompanied by a number

of other hydrocarbons and alcohols. 15 Nonvolatile pungent components include the shogaols and the gingerols, which have been shown to be the antiemetic principles by administration to leopard and ranid frogs, where emesis was induced by the administration of copper sulfate. 16

Numerous references in the medical and the popular press suggest that ginger is useful in preventing or treating a variety of human ail- ments, including migraine headache, elevated cholesterol levels, rheu- matism, hepatotoxicity, burns, peptic ulcers, depression, aging penile vascular changes, and impotence. Evidence supporting such claims is, as yet, insubstantial. The herb does have a long-standing and apparently valid reputation as a digestive aid.

Ginger has also been reported to be useful in the treatment of nausea of all kinds—not just that associated with motion sickness. One study has shown ginger to be as effective as metoclopramide in reducing the incidence of nausea and vomiting in a group of 120 women following elective laparoscopic gynecological surgery on a day-stay basis. The requirement

for postoperative antiemetics was lower in patients who received ginger. 13 However, in a study involving 108 Australian patients undergoing elective gynecological laparoscopic surgery, it was reported that ginger in doses of 0.5 and 1.0 g was ineffective in reducing the incidence of postoperative nausea and vomiting. 14

On the other hand, ginger’s antiemetic action has been shown to be effective in treating hyperemesis gravidum, a severe form of pregnancy- related nausea and vomiting. 20 Vutyavanich and others 21 conducted a randomized controlled trial (RCT) with parallel design to examine the effectiveness of ginger powder against nausea and vomiting in sixty- seven pregnant women who were new obstetric attendees of a prenatal clinic. The patients after each of three daily meals for four consecutive days. A significant improvement was noted in the nausea scores of the ginger group compared to the placebo group, but it was only evident on the fourth day of treatment.

Ginger is ordinarily taken in the form of hard gelatin capsules, each containing 500 mg of the powdered rhizome. To prevent motion sickness, swallow two capsules thirty minutes before departure and then one or two more as symptoms begin to occur, probably about every four hours.

A pleasant way to consume the product is in the form of candied or crys- tallized ginger, which is readily available in Asian food markets. This is

Chapter three: Digestive system problems

27 prepared by boiling the fresh rhizome in a syrup solution, and the resulting

product is marketed in slices sprinkled with granulated sugar. A piece 1 in. square and 0.25 in. thick weighs about 4 g. Because of the loss of some active principles during preparation and the presence of more water in this type of ginger, such a piece is probably equivalent to about one 500-mg capsule.

Backon has noted that ginger inhibits thromboxane synthetase and acts as a prostacyclin agonist. Thus, it could prolong bleeding time and produce immunological changes. In view of this, he suggests caution in using

ginger to treat postoperative nausea. 22 However, although ginger inhibits platelet aggregation in vitro—thus acting as a potent inhibitor of aracha- donic acid, epinephrine, adenosine diphosphate (ADP), and collagen—no bleeding episodes have been associated with its consumption. One case report associated consumption of a marmalade containing 15 percent raw ginger with inhibited platelet aggregation. Three clinical trials designed to look at bleeding risk have been performed with ginger, more than with any other herb. In one of these, a placebo-controlled trial, it was found that a single 10-g rather than a 4-g dose of powdered ginger significantly reduced platelet aggregation in patients with coronary artery disease. 23

In addition to receiving approval of the German Commission E as previously noted, the herb appears on the GRAS (generally recognized as safe) list of the U.S. Food and Drug Administration.

Herbal remedy for nausea and vomiting Ginger