Ginger can help nausea but not for everyone
DOES IT WORK? DÓNAL O'MATHÚNAon ginger for nausea and vomiting
GINGER IS a well-known spice grown mainly in India, Jamaica and China. Ginger has long been used as a medicinal plant and is cited in ancient Indian, Chinese, Arabic, Greek and Roman sources. Ginger has been recommended for many uses, including in cardiovascular health, as an antioxidant and as an anti-inflammatory agent. It is most commonly used medicinally for gastrointestinal problems, especially to prevent nausea and vomiting.
Evidence from studies
Ginger has been studied in a large number of trials, especially compared to other traditional remedies.
The results have been inconsistent, although some of this may be due to the different sources of nausea and vomiting that have been studied.
The evidence is least convincing for motion sickness. Three early studies claimed to find beneficial effects in motion sickness. However, two of the studies involved small numbers of people who were spun on rotating chairs to simulate the feelings of motion sickness. The third involved naval cadets during training in heavy seas, and found ginger no better than placebo in objective tests. Two later studies gave people ginger four hours before travelling and found no beneficial effects.
Another group of studies have examined the effects of ginger after surgery when post-operative nausea and vomiting can occur. A recent review found five studies conducted in such patients. Overall, there was about a third less nausea and vomiting in the groups which received ginger compared to placebo.
This review did not include studies which gave people less than one gram of ginger. In studies where lower doses have been used, the results have been more inconsistent.
Two other studies involved cancer patients receiving ginger to counteract nausea and vomiting from chemotherapy. One study found some beneficial effects, but the other did not.
Ginger has also been tested in several trials involving pregnant women. Although the number of women in each study was relatively small, most studies found that more women taking ginger reported improvements compared to those taking placebo or other remedies. However, relief of morning sickness did not develop for many women until after they had taken ginger for a few days.
Ginger tends to have few adverse effects when taken in the usual dose, which is one gram daily. Larger doses have been found to cause heartburn and abdominal pain. Dividing up the dose throughout the day can sometimes help with this.
Ginger has a reputation for preventing blood clotting. Anyone taking medication to reduce blood clotting (like aspirin or warfarin) might put themselves at increased risk of bleeding if they also take ginger.
Ginger has long been reputed as an antiemetic. The lack of consistency found in some studies of ginger is also found with anti-nausea drugs, arising in part from difficulties measuring subjective symptoms like nausea.
Although ginger appears to have some benefits for morning sickness, its safety during pregnancy has not been carefully studied. Ginger contains numerous chemicals which need to be evaluated thoroughly before being recommended during pregnancy. Although nausea and vomiting can be problematic throughout pregnancy, ginger should not be taken for extended periods or in large doses until more is known about its effects on the foetus.
Conventional treatments for nausea and vomiting are available, but can be problematic for some people. Given the results of recent research and its long tradition of use, ginger may be worth a trial, especially since it is readily available, inexpensive and has few side-effects.
Dónal O’Mathúna has a PhD in pharmacy, researching herbal remedies, and an MA in bioethics, and is a senior lecturer in the School of Nursing, DCU