Ginger (Zingiber officinale Roscoe)
1. Identity: Botanical Classification, Source, and Common Forms
Botanical and Chemical Identity
Zingiber officinale Roscoe (family Zingiberaceae) is one of the most commonly consumed dietary condiments in the world. It is a perennial herb from the Zingiberaceae family, native to the Pacific Islands. It is a flowering tropical plant originating in Southeast Asia and grown in warm climates including China, India, Africa, and the Caribbean. Scientifically known as Zingiber officinale, it is characterised by its thick, knotted rhizome, which is the part most commonly used for culinary and medicinal purposes.
Common Forms and Preparations
Ginger is commonly consumed in fresh root, dried root powder, and capsule (encapsulated dried powder) forms, as a liquid extract, preserved in syrup or sugar, and as a tea. Ginger can be consumed through various dietary sources, though the gingerol content varies significantly between preparations. Fresh ginger root is the most common dietary source; it contains primarily gingerols (not shogaols) and has approximately half the gingerol concentration of dried powder due to water content. Two grams of fresh ginger root provides approximately 10 mg of gingerols — equivalent to one gram of powder.
Shogaols — α,β-unsaturated ketones which are the dehydrated products of gingerols — are the predominant pungent constituents in dried ginger. Zingiber officinale Roscoe is commonly used in food and pharmaceutical products but can also be used in cosmetics and daily necessities.
2. Traditional and Historical Use
Age and Geographic Breadth of Use
Ginger, a member of the Zingiberaceae family, has been cultivated for thousands of years as a spice and for medicinal purposes. Historical records indicate that ginger has been cultivated and traded for more than 5,000 years. Ancient Indian and Chinese cultures valued ginger not only as a spice, but as a staple ingredient in traditional healing preparations, beverages, and ritual foods. From Asia, ginger traveled along early trade routes to the Middle East, Africa, and Europe, where it became one of the most prized spices of the medieval period.
Ayurvedic Medicine
In Ayurvedic medicine, ginger has been used for over 3,000 years as a remedy for gastrointestinal issues, nausea, arthritis, colds, and flu. It is considered a warming spice that improves circulation and digestion. In Ayurveda, ginger is revered for its warming properties and is considered a powerful digestive aid. It is often used to balance the doshas, particularly Vata and Kapha, and is recommended for alleviating nausea, indigestion, and respiratory issues. Ayurvedic practitioners commonly use ginger in various forms, including fresh, dried, or as a powder; it is frequently combined with other spices and herbs to enhance its therapeutic effects.
Traditional Chinese Medicine (TCM)
In Traditional Chinese Medicine, ginger is known as Sheng Jiang and is valued for its ability to dispel cold and dampness from the body. It is often used to treat symptoms such as chills, nausea, and digestive discomfort. Chinese records from the fourth century BC document ginger's use for stomachache, diarrhea, nausea, cholera, hemorrhage, rheumatism, and toothaches. A large portion of traditional Chinese herbal remedies contains ginger.
Other Traditional Systems
Originating in South-East Asia, ginger is one of the most used spices and condiments for foods and beverages. It is also used in traditional medicine for many human disorders including fever, gastrointestinal complications, arthritis, rheumatism, hypertension, and various infectious diseases due to its anti-inflammatory, antioxidant, antimicrobial, and antiemetic properties. Ginger's journey into the Western world began through the spice trade, where it was prized for its culinary value and also adopted for its healing properties.
3. Key Constituents and Active Compounds
Phytochemical Profile
Ginger is a common and widely used spice. It is rich in various chemical constituents, including phenolic compounds, terpenes, polysaccharides, lipids, organic acids, and raw fibers. The health benefits of ginger are mainly attributed to its phenolic compounds, such as gingerols and shogaols.
Zingiber officinale Roscoe contains 194 types of volatile oils, 85 types of gingerol, and 28 types of diarylheptanoid compounds. The phenolic compounds found in ginger are predominantly gingerols, shogaols, and paradols. Gingerols are the major phenolic compounds found in fresh ginger and contain mainly 6-gingerol as well as 4-, 5-, 8-, 10-, and 12-gingerols.
Gingerols
The oleoresin (i.e., oily resin) from the rhizomes of ginger contains many bioactive components, such as [6]-gingerol (1-[4′-hydroxy-3′-methoxyphenyl]-5-hydroxy-3-decanone), which is the primary pungent ingredient that is believed to exert a variety of remarkable pharmacological and physiological activities. Quantitative analysis on dichloromethane extracts of Chinese white ginger and Japanese turmeric found that the highest content of 6-gingerol was 28% and 34%, respectively. The next highest concentrations were 8-gingerol and 10-gingerol.
Shogaols and Other Phenolics
It is believed that the major pharmacologically active components of ginger are gingerols and shogaols. Shogaols — α,β-unsaturated ketones which are the dehydrated products of gingerols — are the predominant pungent constituents in dried ginger. There are also many other phenolic compounds in ginger, such as quercetin, zingerone, gingerenone-A, and 6-dehydrogingerdione.
Volatile Oil Constituents
There are several terpene components in ginger, such as β-bisabolene, α-curcumene, zingiberene, α-farnesene, and β-sesquiphellandrene, which are considered to be the main constituents of ginger essential oils. The main components of the volatile oils of Nigerian ginger were terpenoids such as zingiberene (29.5%) and β-sesquiphellandrene (18.4%), which were quite different from those of ginger grown in other regions.
4. Mechanisms of Action
Anti-Inflammatory Pathways
The anti-inflammatory properties of ginger have been known and valued for centuries. During the past 25 years, many laboratories have provided scientific support for the long-held belief that ginger contains constituents with anti-inflammatory properties. The original discovery of ginger's inhibitory effects on prostaglandin biosynthesis in the early 1970s has been repeatedly confirmed. This discovery identified ginger as an herbal medicinal product that shares pharmacological properties with non-steroidal anti-inflammatory drugs. Ginger suppresses prostaglandin synthesis through inhibition of cyclooxygenase-1 and cyclooxygenase-2.
An important extension of this early work was the observation that ginger also suppresses leukotriene biosynthesis by inhibiting 5-lipoxygenase. Furthermore, ginger compounds such as 6-gingerol and 6-shogaol have an anti-inflammatory effect by inhibiting the production of inflammatory mediators, such as prostaglandin E2, NO, inflammatory cytokines (TNF-α), interleukin-1β (IL-1β), and the pro-inflammatory transcription factor NF-κB.
Gingerol, shogaol, and other structurally-related substances in ginger inhibit prostaglandin and leukotriene biosynthesis through suppression of 5-lipoxygenase or prostaglandin synthetase. Additionally, they can also inhibit synthesis of pro-inflammatory cytokines such as IL-1, TNF-α, and IL-8.
NF-κB Modulation
Ginger has demonstrated efficacy in treating several inflammatory diseases, such as rheumatoid arthritis, ulcerative colitis, and psoriasis, through inhibitory effects on nuclear factor-kappa B (NF-κB) and changes in oxidative stress. Ginger inhibits inflammatory responses by decreasing NF-κB, which results in a decrease in cytokine gene expression.
Antioxidant Activity
Ginger's chemical components are recognized to provide beneficial health effects, namely as antioxidants and anti-inflammatory agents with the potential to operate as immunomodulators. Ginger's antioxidant and anti-inflammatory properties are provided by gingerol, shogaols, paradol, and zingerone.
Pain Modulation
Ginger has a pain-reducing effect and it can modulate pain through various mechanisms: inhibition of prostaglandins via the COX and LOX pathways, antioxidant activity, inhibition of the transcription factor NF-κB, or acting as agonist of vanilloid nociceptor.
5. Scientific Evidence by Area of Use
5.1 Nausea and Vomiting in Pregnancy
Ginger is currently promoted for nausea and vomiting, osteoarthritis, menstrual cramps, and other conditions. There have been many studies on the use of ginger for health purposes in people, but some of them have not been of high quality. Ginger has been studied for several types of nausea and vomiting. Most of the studies tested dietary supplements rather than foods. Research shows that ginger may be helpful for nausea and vomiting associated with pregnancy.
Two meta-analyses of randomized clinical trials (Level I evidence) have been published on nausea and vomiting in pregnancy (NVP). In the smaller of the two meta-analyses, six studies conducted from 1991 to 2009 fulfilled the inclusion criteria, and 508 subjects were randomly assigned to receive ginger (~1000 mg daily) or placebo. These studies varied in the formulation and dosage: three studies administered 250 mg ginger capsules four times daily; one study used 350 mg ginger capsules four times daily; one study administered 250 mg ginger syrup four times daily; and one study administered 500 mg ginger powder in biscuit form, five biscuits daily.
A systematic review including twelve RCTs involving 1278 pregnant women was conducted to assess the evidence on ginger for NVP. Evidence strength: Moderate. The NCCIH characterizes ginger as potentially helpful for pregnancy-associated nausea, based on this body of randomized trial evidence.
5.2 Postoperative Nausea and Vomiting (PONV)
Six studies met all inclusion criteria in an early systematic review of PONV. Three on postoperative nausea and vomiting were identified, and two of these suggested that ginger was superior to placebo and equally effective as metoclopramide. However, the pooled absolute risk reduction for the incidence of postoperative nausea indicated a non-significant difference between the ginger and placebo groups for ginger 1 g taken before operation (absolute risk reduction 0.052; 95% CI −0.082 to 0.186).
Oral ginger was given in the following doses (where the dose was stated): 1 g stat dose; 4 times 250 mg daily for 4 days; or 0.5 g or 1 g at time of premedication or before anaesthesia. It remains uncertain whether ginger is a helpful addition to standard treatments for nausea and vomiting after surgery. Evidence strength: Weak to mixed.
5.3 Chemotherapy-Induced Nausea and Vomiting (CINV)
One systematic review of randomized clinical trials for CINV reviewed 23 RCTs. The effects of ginger supplementation were compared to those of placebo or antiemetic agents. A meta-analysis was conducted after classifying the effects of ginger supplementation on acute and delayed CINV into subgroups due to clinical heterogeneity between these RCTs.
Although the certainty of the effect size estimated in the review was very low, it was believed that ginger supplements were effective in reducing the possibility of acute vomiting. However, the results are not conclusive because the clinical heterogeneity of the current evidence is high. Therefore, all results must be interpreted with caution until additional results are published from a study based on a solid experimental design and well-controlled samples. It is uncertain whether ginger is a helpful addition to standard treatments for nausea and vomiting associated with cancer chemotherapy. Evidence strength: Preliminary; heterogeneous; further high-quality RCTs required.
5.4 Motion Sickness
Most studies of ginger for motion sickness haven't shown it to be helpful. One study was found for seasickness in an early systematic review. Evidence strength: Weak; majority of RCTs show no significant benefit.
5.5 Osteoarthritis
A review of 5 randomized, placebo-controlled clinical trials in which daily doses ranged from 500 mg to 1,000 mg of ginger extract found that ginger may modestly reduce pain and disability from osteoarthritis of the knee and hip. No serious adverse events were reported. A PRISMA systematic review and meta-analysis also found some effectiveness of ginger on pain and function in knee osteoarthritis. The NCCIH notes that ginger dietary supplements might be helpful for symptoms of knee osteoarthritis, but much of the research has been of poor quality.
Both clinical and preclinical studies have suggested that ginger is effective in the treatment of inflammation and is comparable to NSAIDs, but has fewer side effects, particularly concerning the gastrointestinal tract. Evidence strength: Modest and promising, but quality of trials is variable.
5.6 Primary Dysmenorrhea (Menstrual Pain)
Collectively, RCTs provide suggestive evidence for the effectiveness of 750–2000 mg ginger powder during the first 3–4 days of the menstrual cycle for primary dysmenorrhea. One systematic review completed a narrative synthesis of six studies and exploratory meta-analyses of three studies comparing ginger with placebo and two studies comparing ginger with a nonsteroidal anti-inflammatory drug (NSAID). Ginger appeared more effective for reducing pain severity than placebo.
Available data suggest that oral ginger could be an effective treatment for menstrual pain in dysmenorrhea. Findings, however, need to be interpreted with caution because of the small number of studies, poor methodological quality of the studies, and high heterogeneity across trials. The review highlights the need for future trials with high methodological quality. The NCCIH states that research suggests ginger supplements might be helpful for reducing menstrual cramp severity. Evidence strength: Suggestive but preliminary; methodological quality of trials limits conclusions.
5.7 Delayed Onset Muscle Soreness (DOMS)
A narrative review summarized the last ten years of randomized controlled trials, in which ginger was used as a pain reliever for dysmenorrhea, DOMS, osteoarthritis, chronic low back pain, and migraine. Regarding dysmenorrhea, six eligible studies suggest a promising effect of oral ginger. As concerned with DOMS, the four eligible RCTs suggested a reduction of inflammation after oral and topical ginger administration.
In a quasi-experimental study, 36 healthy female subjects were randomly divided into groups receiving ginger intake before or after exercise or placebo. Subjects consumed capsules containing 60 mg of ginger extract (equivalent of 2 g dried ginger powder) or placebo before and after exercise. The finding of this study suggests that 2 grams of ginger may have anti-inflammation and analgesic effect on DOMS. Evidence strength: Preliminary; small trials; limited human data.
5.8 Type 2 Diabetes Mellitus and Glycemic Control
A meta-analysis of 10 studies meeting inclusion criteria with a total of 490 individuals found that ginger showed a significant beneficial effect in glucose control and insulin sensitivity. The pooled weighted mean difference (MD) of glycosylated hemoglobin (HbA1c) was −1.00 (95% CI: −1.56, −0.44; P < 0.001). Subgroup analysis revealed that ginger obviously reduced fasting blood glucose (FBG) in T2DM patients (−21.24; 95% CI: −33.21, −9.26; P < 0.001).
In another systematic review and meta-analysis, capsules containing Zingiber officinale powder were supplemented twice a day; the dose ranged from 1.2 to 2 g/day, and the intervention period ranged from 4 to 12 weeks. Meta-analysis results in this review indicated no significant effect of ginger supplementation on fasting blood sugar or HbA1c. However, individual studies reported mixed results, with two studies showing a significant reduction in FBG.
A recent systematic review published in Frontiers in Pharmacology collated and synthesized five high-quality clinical publications (meta-analyses) to investigate the effects of ginger on inflammation, blood sugar, and other physiological metrics. Review findings confirm that ginger supplementation significantly reduces key markers of inflammation, lowers blood glucose and glycohemoglobin (HbA1c) in type 2 diabetes, and improves antioxidant status. The mechanism by which ginger improves glucose tolerance remains uncertain and even which bioactive compound in ginger is responsible for its antidiabetic efficacy is unknown, although it is likely that 6-gingerol, the predominant pungent compound in ginger, is responsible for its benefits. Evidence strength: Mixed to promising; meta-analyses reach conflicting conclusions; larger, methodologically robust RCTs required.
5.9 Lipid Profile and Cardiovascular Markers
Ginger also had a statistically significant positive effect on blood pressure, weight management, dysmenorrhea, postoperative nausea, and chemotherapy-induced vomiting (effect size: moderate to large; GRADE: low to moderate) as well as blood lipid profile (effect size: small; GRADE: very low) and anti-inflammatory and antioxidant biomarkers (effect size: unclear; GRADE: very low to moderate).
Nine systematic reviews explored the effect of ginger on metabolic conditions. The overall finding was consistent evidence of a moderate to large beneficial effect for cardiovascular health, glycemic control, and weight management. One study showed that 2 g powdered ginger reduced plasma insulin, insulin resistance assessed by HOMA, serum fasting triglyceride, and LDL in type 2 diabetic patients; however, no significant changes were seen in blood glucose, total cholesterol, or HDL levels. The effect of ginger supplementation on lipid profile in humans remains controversial, particularly in diabetic patients. Evidence strength: Low to moderate GRADE; small effect sizes on lipids; cardiovascular data are preliminary.
5.10 Cancer: Chemopreventive and Anti-Tumor Properties
The anticancer potential of ginger is well documented and its functional ingredients like gingerols, shogaol, and paradols are valuable ingredients which can prevent various cancers, angiogenesis and metastasis, induction of apoptosis, and inhibition of cell-cycle progression. Cell cycle is critical to maintaining cell proliferation and tissue integrity; its deregulation is often responsible for cancer onset and progression. Experimental studies demonstrated that some ginger derivatives were able to modulate cell cycle progression as part of their chemopreventive mechanism. For example, in work regarding the treatment of breast cancer cells with 6-shogaol, arrest of the cell cycle in G2/M phase was reported in both monolayer and cancer-stem cell-like spheroids.
Evidence strength: Predominantly preclinical (in vitro and animal models). As of current evidence, there are no published clinical trials in humans demonstrating ginger as a direct anticancer therapeutic agent. The existing evidence is mechanistic and experimental.
6. Body Systems and Health Areas Associated with Ginger
- Gastrointestinal system: Ginger has been used in the prevention and treatment of digestive, circulatory, respiratory, and central nervous system diseases and other diseases. Its most robustly supported application is in nausea and vomiting.
- Musculoskeletal system: Osteoarthritis pain and stiffness, rheumatoid arthritis, delayed onset muscle soreness, and chronic low back pain have been studied in RCTs.
- Reproductive and endocrine system: Primary dysmenorrhea and nausea in pregnancy are supported by multiple systematic reviews.
- Metabolic and cardiovascular system: Accumulated investigations have demonstrated that ginger possesses multiple biological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, neuroprotective, cardiovascular protective, respiratory protective, antiobesity, antidiabetic, antinausea, and antiemetic activities.
- Immune system: The complex interaction between inflammation, oxidative stress, and immunity contributes to a plethora of pharmacological activities of ginger's compounds. The immunomodulatory properties of these compounds, which affect the immune system, have been the focus of many studies.
7. Dosage Forms and Doses Reported in Studies
Dosage of 0.5–3 g/day in capsule form administered for up to 3 months was consistently reported as effective across studies included in an umbrella review.
- Nausea in pregnancy: Studies administered 250 mg ginger capsules four times daily (total 1,000 mg/day); one study used 350 mg four times daily; one study administered 250 mg ginger syrup four times daily; and one study administered 500 mg ginger powder in biscuit form, five biscuits daily.
- PONV: Oral ginger was given in the following doses: 1 g stat dose; 4 times 250 mg daily for 4 days; or 0.5 g or 1 g at time of premedication or before anaesthesia.
- CINV: A standardized ginger extract of 1.2 g per day divided into four capsules (300 mg per capsule, q.i.d.) for five days during chemotherapy cycles was used in one trial protocol.
- Osteoarthritis: Daily doses ranged from 500 mg to 1,000 mg of ginger extract in the reviewed trials.
- Primary dysmenorrhea: RCTs provide suggestive evidence for the effectiveness of 750–2000 mg ginger powder during the first 3–4 days of the menstrual cycle.
- Type 2 diabetes: Capsules containing Zingiber officinale powder were supplemented twice a day; the dose ranged from 1.2 to 2 g/day, and the intervention period ranged from 4 to 12 weeks.
- DOMS: Subjects consumed capsules containing 60 mg of ginger extract (equivalent of 2 g dried ginger powder) or placebo before or after exercise in one study.
8. Safety Considerations and Drug Interactions
General Tolerability
Ginger has been used safely in many research studies where it was taken orally as a dietary supplement. Ginger products may also be safe for topical use. Ginger can have side effects such as abdominal discomfort, heartburn, diarrhea. Side effects reported in clinical studies tend to be mild and include stomach upset, heartburn, diarrhea, mouth and throat irritation, nausea, reduced appetite, constipation, and complaints of "bad taste." Long-term safety studies have not been conducted.
Anticoagulant and Antiplatelet Interactions
It is well-documented that ginger is an anti-coagulant, and this will be of importance in connection with patients taking drugs like warfarin. While there has been no direct advisory against the incorporation of ginger in the diets of patients who are anticoagulated with warfarin, there is a warning from the Food and Drug Administration (FDA) advising healthcare providers to be cautious in patients who are on warfarin and who also use ginger, garlic, and other dietary and herbal supplements. This highlights a case where an oral ginger supplement altered the anticoagulant effects of warfarin.
A 70-year-old woman on a stable warfarin regimen experienced a significant increase in INR from 2.7 to 8.0 one month after beginning a ginger supplement providing 48 mg of dried ginger root daily. Krüth et al. reported possible over-anticoagulation resulting from a possible ginger-phenprocoumon interaction. A 76-year-old woman on long-term phenprocoumon therapy presented with epistaxis and an INR of >10. For several weeks prior to the event, the woman had a regular ginger intake of dried ginger pieces and tea from ginger powder.
A particularly important finding is the synergistic effect between ginger and nifedipine on anti-platelet aggregation. Ginger may increase bleeding risk in people taking blood-thinning medications including warfarin, aspirin, clopidogrel, heparin, and ticlopidine.
Hypoglycemic Interactions
Ginger may increase hypoglycemia risk in individuals taking oral hypoglycemics or insulin. Given that human RCTs have demonstrated blood-glucose lowering effects at doses of 1.2–2 g/day, concurrent use with antidiabetic medications warrants monitoring.
Pregnancy
The Finnish Food Authority issued a recommendation against the use of products containing ginger concentrate or extract, ginger tea, and food supplements containing ginger by pregnant and breastfeeding women, infants, toddlers, schoolchildren, elderly, and individuals with weakened immunity. In a systematic review of 777 patients in 15 studies, 3.3% had mild adverse reactions, mainly mild gastrointestinal symptoms and sleepiness, not requiring specific treatment. There was one serious adverse event — abortion in the 12th week of gestation — but that could not clearly be attributed to the ginger. The Norwegian Food Safety Authority concluded that while a woman of 70 kg would consume less ginger (124 mg to 329 mg), there remains cause for concern and fetal risk cannot be excluded.
Studies on fetal development in animal models reported improvements in birth weight, growth metrics, and reductions in death rates when ginger was administered at moderate doses (specifically ginger tea 20 g/L–50 g/L or gingerol 25 mg/kg body weight). However, higher doses (specifically 2,000 mg/kg body weight Zingiber officinale) caused adverse reproductive outcomes such as reduced weight gain, maternal toxicity, disrupted estrous cycle, and increased fetal death.
Caution Note on Mechanisms
Although ginger is generally considered to be safe, the lack of a complete understanding of its mechanisms of action suggests caution in its therapeutic use.
References
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