Reviewed: Giacosa A, Guido D, Grassi M, et al. The effect of ginger (Zingiber officinalis [sic]) and artichoke (Cynara cardunculus) extract supplementation on functional dyspepsia: a randomised, double-blind, and placebo-controlled clinical trial [published online April 14, 2015]. Evid Based Complement Alternat Med. doi: 10.1155/2015/915087.
Functional dyspepsia (FD) refers to indigestion or problems with the gastrointestinal (GI) tract that are not related to irritable bowel syndrome (IBS) or gastroesophageal reflux (which causes heartburn, among other symptoms). FD symptoms often appear during or after meals, and include pain, bloating, and nausea, among others. FD is thought to result from various factors, including postprandial sensitivity to distension, insufficient stomach relaxation, and gastric muscle and/or nervous system dysfunction, although the exact causes are unknown. Both ginger (Zingiber officinale, Zingiberaceae) rhizome and cardoon* leaves are used to treat GI complaints, such as nausea and dyspepsia. The purpose of this randomized, placebo-controlled, double-blind trial was to investigate the effects of a combination of ginger and cardoon extracts on FD intensity and symptoms.
Men and women with FD were recruited from two health care facilities in Italy. FD was defined as upper abdominal pain characterized by early satiety, postprandial fullness, bloating and/or nausea, occurring for at least three months during the previous year with no identifiable underlying structural or biochemical cause. Patients were excluded if they had relevant gastroesophageal reflux symptoms or IBS, had a history of cancer or GI surgery, had a Helicobacter pylori bacterial infection or an ulcer, or were pregnant. Patients who were taking medications that could act on the GI system (e.g., nonsteroidal anti-inflammatory drugs) were asked to stop taking them one month before the start of the study. Pre-trial screening included a physical exam, ultrasound, blood test, and endoscopy.
This study’s primary outcome measure was patient-reported changes in FD intensity throughout the study. To gauge this, participants used a scale from 0-3 (0 = no improvement or worse, 1 = slightly improved, 2 = markedly improved, and 3 = completely improved). Secondary outcome measures included changes in epigastric fullness, bloating, early satiety, nausea, vomiting, and epigastric pain. These symptoms were also rated on a scale from 0-3 (0 = no symptom, 3 = severe symptom). Patients made four clinic visits. The first consisted of the initial screening, the second was considered baseline and occurred 28 days after the first visit, the third occurred after two weeks of treatment, and the fourth occurred after four weeks of treatment. Primary and secondary outcome measures were assessed at the third and fourth visits. Patients were instructed to limit alcohol consumption to no more than two drinks per day, and to refrain from consuming foods that could affect the motility and secretions of the GI tract.
The treatment consisted of gelatin capsules containing 100 mg cardoon and 20 mg ginger standardized extracts (“ProDigest”) provided by the manufacturer (Indena SpA; Milan, Italy). The extraction process, plant parts used, and content(s) of placebo were not described. According to the authors, “The comparison with placebo [was] chosen in absence of an evidence-based choice treatment of functional dyspepsia.” The cardoon material was standardized to contain > 20% caffeoylquinic acid, > 5% flavonoids, and > 5% cynaropicrin. Ginger was standardized to contain 25-30% gingerols. Enrolled patients were randomly assigned to either the combination treatment or placebo group and took two capsules per day, one before lunch and dinner, for four weeks. Researchers monitored the subjects’ vital signs, laboratory parameters, treatment tolerability, and potential adverse side effects.
In total, 126 patients met the inclusion criteria and were randomly assigned to the treatment group (n = 65; 19 men, 46 women) or placebo group (n = 61; 20 men, 41 women). No dropouts were reported, and all patients were included in the final analysis. At baseline, the average age of participants in the treatment group and the placebo group (45.8 and 48 years, respectively) was homogeneous; however, bloating, satiety, and epigastric pain scores were significantly higher in the placebo group at baseline (P = 0.011, P = 0.004, and P = 0.022, respectively).
At four weeks, 63.1% of the treatment group showed marked or complete improvement (ratings of 2 or 3) in FD intensity compared with 24.6% of those in the placebo group. At two weeks, only the treatment group showed a statistically significant improvement in overall FD score (P = 0.017). There were no significant differences in FD intensity scores (across groups and over time) when the authors compared ratings from week four to those from week two.
In the treatment group, a significant reduction in both nausea (P = 0.03) and epigastric pain (P = 0.036) scores was observed over the course of the study. Conversely, in the placebo group, there was an increase in the intensity of all observed symptoms, with a significant increase in vomiting (P = 0.03). No adverse side effects were detected.
Results from this study suggest that a combination of cardoon and ginger extracts is effective in reducing self-rated intensity of FD and associated nausea and epigastric pain. Previous research has shown that ginger can impact digestive tract motility, gastric emptying, and emesis, which some attribute to the presence of gingerols and shogaols. These compounds are thought to interact with neurotransmitter receptors involved in nausea and vomiting and may explain the bioactivity observed in this study. The combination of ginger and cardoon leaf extracts may be an effective alternative for symptom control for those suffering from FD, although more research is needed.
Editor’s note: Three out of the nine authors of this study (A. Riva, P. Morazzoni, and E. Bombardelli) are employees of Indena, the manufacturer and supplier of the herbal product used in this study.
—Amy C. Keller, PhD