Ginger Extract

• Anti-inflammatory effects
• Antioxidant protection
• Digestive health support
• Immune system modulation

• Nausea and vomiting reduction
• Joint pain relief
• Blood sugar regulation
• Cardiovascular health support
• Cognitive function support
• Respiratory health

Ginger extract exerts its biological effects through a complex array of bioactive compounds, with gingerols (particularly 6-gingerol, 8-gingerol, and 10-gingerol) and shogaols being the primary active constituents, along with paradols, zingerone, and various terpenes. The anti-inflammatory properties of ginger extract operate through multiple pathways. It inhibits cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2) enzymes, reducing the production of pro-inflammatory prostaglandins and thromboxanes. Gingerols and shogaols also suppress the activity of 5-lipoxygenase (5-LOX), decreasing the synthesis of inflammatory leukotrienes.

Additionally, ginger extract inhibits the nuclear factor-kappa B (NF-κB) signaling pathway, a master regulator of inflammation, thereby reducing the expression of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-1 beta (IL-1β), and interleukin-6 (IL-6). The antioxidant effects of ginger extract stem from its ability to neutralize free radicals and reactive oxygen species (ROS) through direct scavenging activity. Gingerols and shogaols donate hydrogen atoms to free radicals, effectively terminating the oxidation chain reaction. Ginger extract also enhances the body’s endogenous antioxidant defense system by activating nuclear factor erythroid 2-related factor 2 (Nrf2), which increases the expression of antioxidant enzymes such as glutathione peroxidase, superoxide dismutase, and catalase.

Furthermore, ginger compounds can chelate metal ions that catalyze oxidation reactions, providing additional protection against oxidative stress. Ginger extract’s antiemetic (anti-nausea) properties, one of its most well-documented effects, involve multiple mechanisms. It enhances gastric emptying and gastrointestinal transit through antagonism of 5-hydroxytryptamine-3 (5-HT3) receptors in the gastrointestinal tract, similar to conventional antiemetic medications. Gingerols and shogaols also appear to have a mild inhibitory effect on serotonin receptors in the central nervous system and may influence the release of vasopressin, a hormone involved in nausea and vomiting.

Additionally, ginger extract’s antiemetic effects may be partially attributed to its anti-inflammatory actions in the gastrointestinal tract. For digestive health, ginger extract stimulates the production of digestive enzymes, including amylase, lipase, and proteases, enhancing the breakdown of macronutrients. It increases bile secretion from the liver and improves bile flow, facilitating fat digestion. Ginger extract also promotes gastric emptying and intestinal motility through its cholinergic and serotonergic effects, helping to alleviate symptoms of functional dyspepsia and irritable bowel syndrome.

The carminative properties of ginger reduce intestinal gas and bloating by relaxing intestinal smooth muscle and preventing spasms. In terms of cardiovascular effects, ginger extract inhibits platelet aggregation through inhibition of thromboxane synthesis and interference with platelet activation factors. It may modestly reduce blood pressure by promoting vasodilation through calcium channel blocking activity and stimulation of nitric oxide production. Ginger extract also demonstrates potential cholesterol-lowering effects by inhibiting hepatic cholesterol synthesis and enhancing bile acid excretion.

For blood glucose regulation, ginger extract enhances insulin sensitivity in peripheral tissues by activating peroxisome proliferator-activated receptor gamma (PPAR-γ) and adenosine monophosphate-activated protein kinase (AMPK) pathways. It inhibits key enzymes involved in carbohydrate metabolism, such as α-amylase and α-glucosidase, slowing glucose absorption. Additionally, ginger compounds protect pancreatic β-cells from oxidative damage and may stimulate insulin secretion. The immunomodulatory effects of ginger extract involve enhancement of both innate and adaptive immune responses.

It increases the activity of natural killer (NK) cells and macrophages, which are crucial for the body’s first line of defense against pathogens. Ginger extract modulates T-cell differentiation and cytokine production, potentially helping to balance immune responses without causing immunosuppression. It also exhibits direct antimicrobial properties against various bacteria, fungi, and viruses, contributing to its immune-supporting effects. For joint health, beyond its general anti-inflammatory effects, ginger extract specifically reduces the production of inflammatory mediators in synovial cells and chondrocytes.

It inhibits the expression of matrix metalloproteinases (MMPs) that degrade cartilage and may have chondroprotective effects by promoting the synthesis of glycosaminoglycans and collagen. In the respiratory system, ginger extract acts as an expectorant and bronchodilator. It helps loosen mucus and phlegm, making it easier to expel from the airways. The extract’s volatile compounds may also have a direct relaxant effect on bronchial smooth muscle, improving airflow in conditions like asthma and bronchitis.

For cognitive function, emerging research suggests that ginger extract may protect against neurodegenerative processes through its antioxidant and anti-inflammatory effects in the central nervous system. It may enhance cholinergic neurotransmission and protect against amyloid-beta-induced cognitive deficits, potentially benefiting conditions like Alzheimer’s disease.

Ginger extract dosages vary depending on the form, concentration, and intended use. For standardized ginger extract (typically standardized to 5-10% gingerols), common dosages range from 100-2000 mg daily, divided into 1-4 doses. For fresh ginger root, 1-4 grams daily is commonly used. Ginger tea can be prepared using 1-2 teaspoons (approximately 2-4 grams) of freshly grated ginger root per cup of hot water, consumed 1-3 times daily.

For ginger essential oil, which is highly concentrated, typical dosages range from 1-3 drops taken 1-3 times daily, always diluted in a carrier oil or liquid.

The bioavailability of ginger extract varies significantly depending on the form, processing method, and specific bioactive compounds. Gingerols, the primary active compounds in fresh ginger, are relatively well-absorbed in the gastrointestinal tract, with bioavailability estimated at 30-70%. However, they are thermally labile and can convert to shogaols during processing or storage at high temperatures. Shogaols generally demonstrate higher bioavailability than gingerols due to their increased lipophilicity, with absorption rates estimated at 50-80% under optimal conditions.

After oral administration, peak plasma concentrations of gingerols are typically reached within 30-60 minutes, while shogaols may take 1-2 hours to reach maximum concentration. Both compounds undergo extensive first-pass metabolism in the liver, where they are primarily conjugated with glucuronic acid and sulfate. This metabolism significantly reduces the systemic availability of free, unconjugated compounds, with studies indicating that only about 15-30% of the absorbed gingerols and shogaols remain in their free, active form after hepatic metabolism. The water-soluble components in ginger tea or water extracts generally have lower bioavailability (20-40%) compared to lipid-soluble extracts or formulations that include emulsifiers.

Consuming ginger extract with a fat-containing meal increases absorption of lipophilic compounds by 30-50%, Standardized extracts with higher gingerol and shogaol content (>5%) generally provide better bioavailability of active compounds, Liposomal delivery systems can enhance bioavailability by up to 2-3 times compared to standard extracts, Combining with black pepper extract (piperine) may enhance absorption by inhibiting certain detoxification enzymes, potentially increasing bioavailability by 30-60%, Supercritical CO2 extraction methods yield extracts with higher concentrations of bioactive compounds and potentially better absorption profiles, Nano-emulsified formulations can increase the surface area of ginger compounds, enhancing dissolution and absorption rates by up to 200%, Phytosome technology, which incorporates ginger compounds into phospholipid complexes, has been shown to increase bioavailability by 2-4 times, Enteric-coated capsules protect active compounds from stomach acid degradation, potentially improving delivery to the intestines, Fermentation of ginger can transform certain compounds into more bioavailable metabolites and increase the overall absorption efficiency, Combining with medium-chain triglycerides (MCT oil) can enhance absorption of fat-soluble components

For digestive issues, take ginger extract 15-30 minutes before meals to optimize effects on gastric emptying and digestive enzyme secretion. For nausea and vomiting prevention, take 30-60 minutes before the anticipated nausea-inducing event (travel, chemotherapy, etc.). For systemic effects (anti-inflammatory, antioxidant benefits), take with meals containing some fat to enhance absorption of lipophilic compounds. When using multiple doses throughout the day, space them evenly (e.g., morning, midday, and evening) to maintain consistent blood levels of active compounds.

For acute conditions like motion sickness or migraine, sublingual administration of liquid extracts may provide faster onset of action by partially bypassing first-pass metabolism. For joint pain and inflammation, consistent daily use with doses divided throughout the day typically provides better results than a single large dose. Morning dosing may be preferable for conditions that tend to worsen throughout the day, such as osteoarthritis pain. For blood sugar management, taking ginger extract 15-30 minutes before meals may help optimize its effects on carbohydrate digestion and glucose metabolism.

Cycling ginger extract (e.g., 5 days on, 2 days off) may help prevent tolerance development for long-term use, particularly for digestive and anti-inflammatory applications.

• Mild gastrointestinal discomfort (heartburn, gas, bloating)
• Burping or reflux, particularly with higher doses
• Mouth and throat irritation (especially with concentrated extracts)
• Mild diarrhea (typically with doses exceeding 2 grams daily)
• Temporary warming sensation in the stomach
• Mild headache (rare)
• Menstrual irregularities with very high doses (rare)
• Skin rash or contact dermatitis (primarily with topical application)
• Temporary increase in heart rate (with very high doses)
• Drowsiness (rare)
• Mild dizziness (rare)
• Temporary reduction in blood glucose levels (may be beneficial in some cases but problematic for diabetics on medication)

• Known allergy or hypersensitivity to ginger or plants in the Zingiberaceae family
• Bleeding disorders or use of anticoagulant medications (relative contraindication – may be used with caution and monitoring)
• Upcoming surgery (discontinue at least 2 weeks before due to potential mild anticoagulant effects)
• Gallstones or biliary tract obstruction (ginger may increase bile production)
• Severe cardiovascular conditions (due to potential mild effects on heart rate and blood pressure)
• Pregnancy with history of miscarriage or bleeding (high doses only)
• Severe gastroesophageal reflux disease (GERD) or gastric ulcers (may exacerbate symptoms in some individuals)

• Anticoagulant and antiplatelet medications (warfarin, aspirin, clopidogrel) – potential for additive effects and increased bleeding risk
• Antidiabetic medications – may enhance hypoglycemic effects, requiring dose adjustments
• Calcium channel blockers – potential for additive effects on blood pressure
• Medications metabolized by cytochrome P450 enzymes (particularly CYP2C9, CYP2D6, and CYP3A4) – may affect drug metabolism
• Antacids – may reduce absorption of ginger compounds
• Proton pump inhibitors and H2 blockers – may alter absorption of ginger compounds
• CNS depressants – theoretical risk of additive sedative effects with very high doses
• Tacrolimus – may affect blood levels of this immunosuppressant
• Nifedipine – may increase the bioavailability of this calcium channel blocker
• Phenprocoumon – may increase INR values when used concurrently

For standardized ginger extract, most research suggests that doses up to 4 grams daily are generally safe for most adults when used short-term (up to 3 months). For long-term use (beyond 3 months), a more conservative upper limit of 1-2 grams daily is recommended to minimize the risk of side effects. For pregnant women, doses should not exceed 1 gram daily, divided into smaller doses. For essential oil of ginger, which is highly concentrated, the upper limit is approximately 10-15 drops daily, always properly diluted.

Higher doses increase the risk of gastrointestinal side effects without necessarily improving therapeutic outcomes. For individuals with bleeding disorders or those taking anticoagulant medications, lower doses (not exceeding 1 gram daily) are advisable, and medical supervision is recommended.

In the United States, ginger is generally recognized as safe (GRAS) for use as a food flavoring and spice under 21 CFR 182.10 and 182.20. As a dietary supplement, ginger extract falls under the Dietary Supplement Health and Education Act (DSHEA) of 1994, which means it can be marketed without prior FDA approval as long as no specific health claims are made regarding the treatment, prevention, or cure of diseases. The FDA does not evaluate the safety or efficacy of ginger supplements before they reach the market but can take action against products found to be unsafe or making unsubstantiated health claims. Manufacturers are required to ensure their products are safe before marketing and must notify the FDA of any serious adverse events reported by consumers.

For specific medical applications, the FDA has acknowledged ginger as an antiemetic in certain over-the-counter (OTC) drug products, though it is not included in the final monograph for OTC antiemetic drug products. Ginger is not approved by the FDA for use as a drug for any specific indication and cannot be marketed with therapeutic claims for treating specific conditions.

Eu: In the European Union, ginger is listed in the European Medicines Agency (EMA) database of herbal substances. The Committee on Herbal Medicinal Products (HMPC) has established a community herbal monograph for Zingiber officinale rhizome, recognizing its traditional use for the prevention of motion sickness and for symptomatic treatment of mild, spasmodic gastrointestinal complaints including bloating and flatulence. This allows products meeting specific quality and labeling requirements to be registered as traditional herbal medicinal products. For food use, ginger extract is regulated under Regulation (EC) No 1334/2008 on flavorings and is approved as a food additive. As a food supplement, ginger products must comply with the Food Supplements Directive 2002/46/EC. The European Food Safety Authority (EFSA) has evaluated several health claims for ginger under Regulation (EC) No 1924/2006 but has not approved any specific health claims due to insufficient scientific evidence.

Canada: Health Canada has included ginger in the Natural Health Products Ingredients Database with a medicinal ingredient monograph. It is approved for use in Natural Health Products (NHPs) with specific guidelines for dosage, contraindications, and warnings. Approved uses include: 1) To help prevent nausea and vomiting associated with motion sickness, 2) To help relieve digestive upset/disturbances including lack of appetite, nausea, digestive spasms, indigestion, dyspepsia and flatulent colic (carminative), and 3) To help relieve nausea and vomiting of pregnancy. Ginger products must have a Natural Product Number (NPN) to be legally sold in Canada as natural health products. For food use, ginger extract is regulated as a food flavoring agent.

Australia: The Therapeutic Goods Administration (TGA) in Australia regulates ginger extract as a listed complementary medicine when used for therapeutic purposes. Products containing ginger must be included in the Australian Register of Therapeutic Goods (ARTG) before they can be marketed. The TGA recognizes several traditional and evidence-based indications for ginger, including for relief of nausea, digestive complaints, and mild rheumatic pain. For food use, Food Standards Australia New Zealand (FSANZ) regulates ginger extract as a food flavoring substance. Ginger is also included in the TGA’s list of substances that may be used in listed medicines, with specific guidelines for quality, dosage, and labeling requirements.

Low to medium, depending on concentration and quality

For standardized ginger extract (typically standardized to 5-10% gingerols), the cost ranges from $0.10 to $0.50 per effective daily dose (500-1000 mg). Fresh ginger root is the most economical form, costing approximately $0.05 to $0.15 per effective dose (1-2 grams). Ginger tea bags typically cost $0.15 to $0.30 per cup. Specialized formulations such as liposomal or high-potency extracts can cost $0.75 to $2.00 per daily dose.

Ginger extract offers excellent value for specific applications, particularly for nausea relief and as a general anti-inflammatory. When compared to conventional antiemetic medications, high-quality ginger extract provides comparable relief for mild to moderate nausea at a fraction of the cost, though with potentially slower onset of action. For pregnancy-related nausea, ginger represents one of the most cost-effective interventions with a favorable safety profile. For osteoarthritis and joint pain, ginger extract is significantly more economical than many prescription NSAIDs and COX-2 inhibitors, though it may require longer consistent use (2-4 weeks) to achieve optimal effects.

While the initial response may be less dramatic than pharmaceutical options, the favorable side effect profile and lower cost make it an excellent value, particularly for long-term use. The wide availability of different forms allows consumers to choose the most cost-effective option for their specific needs. Raw ginger root provides the best value for regular use in cooking and tea preparation, while standardized extracts offer better value for therapeutic applications requiring precise dosing. The concentrated nature of ginger extract means a small bottle of tincture or package of capsules can last for weeks to months of regular use, improving its long-term value proposition.

However, the wide variation in product quality significantly impacts cost-efficiency. Low-cost products often contain minimal levels of active compounds or use inferior extraction methods, potentially providing little therapeutic benefit despite the lower price point. For digestive issues, enteric-coated capsules provide better value despite higher cost, as they deliver active compounds directly to the intestines where they’re needed. When considering the full economic impact, ginger extract may offer indirect cost savings by potentially reducing the need for over-the-counter medications for minor ailments like nausea, digestive discomfort, or inflammatory pain.

For preventative use, such as preventing motion sickness or supporting general anti-inflammatory status, ginger represents one of the most cost-effective natural options available.

Properly stored ginger extract typically maintains its potency for 2-3 years from the date of production, though this varies by formulation. Standardized ginger extracts in capsule or tablet form generally have a shelf life of 2-3 years when stored according to manufacturer recommendations. Liquid extracts and tinctures have a shorter shelf life of approximately 1-2 years once opened, due to potential oxidation and microbial contamination. Ginger essential oil can remain stable for 3-5 years when properly stored in dark glass containers away from heat and light.

Fresh ginger root powder has the shortest shelf life, typically 1-2 years, with gradual loss of volatile compounds and conversion of gingerols to shogaols over time. Freeze-dried ginger preparations generally maintain stability longer than air-dried products due to reduced moisture content and minimal heat exposure during processing.

Store ginger extract products in cool, dry places away from direct sunlight and heat sources, ideally at temperatures between 15-25°C (59-77°F). Capsules and tablets should be kept in their original containers with desiccant packets if provided to protect from moisture. For liquid extracts and tinctures, tightly seal containers after each use to prevent oxidation and evaporation of volatile compounds. Refrigeration can extend the shelf life of liquid extracts but is not necessary for capsules, tablets, or properly sealed essential oils.

Avoid storing near strong-smelling substances as ginger products may absorb other odors or release their aroma into nearby products. For essential oil of ginger, use dark amber or blue glass bottles to protect from light degradation, as UV exposure can accelerate the breakdown of volatile compounds. If transferring liquid extracts to another container, use glass rather than plastic, as the concentrated compounds can interact with certain plastics over time. Avoid frequent temperature fluctuations, which can cause condensation inside containers and accelerate degradation through moisture introduction.

Exposure to oxygen – Causes oxidation of gingerols and other phenolic compounds, reducing their biological activity. Oxidized gingerols may form polymers that alter the extract’s efficacy and appearance., Heat – Temperatures above 30°C (86°F) accelerate the conversion of gingerols to shogaols and the loss of volatile compounds. While shogaols have their own biological activity, this conversion changes the extract’s properties and may reduce certain effects., Light exposure – Particularly UV light, which degrades both gingerols and shogaols, reducing the extract’s potency. Light exposure also affects the volatile oil components, changing the aromatic profile., Moisture – Promotes hydrolysis of certain compounds and increases the risk of microbial contamination, particularly in powdered extracts and capsules. Even small amounts of moisture can initiate enzymatic degradation processes., pH extremes – Gingerols are most stable at slightly acidic to neutral pH (5-7). Strongly acidic or alkaline environments can accelerate degradation through various chemical reactions., Microbial contamination – Can lead to breakdown of active compounds and production of potentially harmful metabolites, particularly in liquid extracts with insufficient preservatives., Enzymatic activity – Residual enzymes from the ginger plant, particularly polyphenol oxidases, can continue to catalyze degradation reactions if not properly inactivated during processing., Metal ions – Particularly iron and copper, which can catalyze oxidation reactions of phenolic compounds in ginger extract, accelerating degradation. Contact with metal containers should be avoided., Freeze-thaw cycles – Repeated freezing and thawing can damage the physical structure of the extract and accelerate chemical degradation through ice crystal formation and concentration effects.

Synthesis Methods

Natural Sources

Quality Considerations

Ginger has one of the longest documented histories of medicinal use, spanning over 5,000 years across multiple civilizations. In ancient China, ginger was first mentioned in the Shennong Ben Cao Jing, a Chinese pharmacopeia dating to around 2700 BCE, where it was classified as a ‘superior’ herb that could ‘harmonize the middle’ and ‘warm the stomach.’ Chinese medicine traditionally used ginger to treat digestive disorders, respiratory conditions, and cold-induced ailments. It was considered a warming herb that could expel cold, stop coughing, and reduce nausea. In ancient India, ginger (known as ‘adrak’ fresh and ‘sonth’ when dried) has been a cornerstone of Ayurvedic medicine since at least 2000 BCE.

Ayurvedic texts describe ginger as ‘vishwabhesaj’ or ‘universal medicine,’ highlighting its importance. It was used to enhance digestion (deepana), stimulate appetite (rochana), alleviate nausea, reduce inflammation, and treat respiratory conditions. Ayurvedic practitioners valued ginger for its ‘katu’ (pungent) and ‘ushna’ (hot) properties, which were believed to balance ‘kapha’ and ‘vata’ doshas. The ancient Greeks and Romans also prized ginger for both culinary and medicinal purposes.

By the 1st century CE, ginger was being imported to the Mediterranean from India, with the Greek physician Dioscorides documenting its medicinal properties in his De Materia Medica. He recommended ginger for warming the stomach, aiding digestion, and treating stomach ailments. The Roman physician Pliny the Elder noted ginger’s use for digestive issues, respiratory problems, and as an antidote to certain poisons. In medieval Europe, ginger became one of the most valued and expensive spices, second only to pepper.

The 11th-century German abbess and herbalist Hildegard of Bingen recommended ginger for digestive ailments and as a heart tonic. During the plague epidemics, ginger was included in protective herbal formulations due to its warming and purifying properties. By the 16th century, the famous herbalist Nicholas Culpeper described ginger as effective for ‘cold and windy disorders’ of the body, particularly of the digestive and respiratory systems. In traditional Arabic medicine (Unani), ginger was incorporated into the materia medica following the translations of Greek medical texts.

The influential Persian physician Avicenna (980-1037 CE) included ginger in his Canon of Medicine, recommending it for digestive disorders, respiratory conditions, and joint pain. In the Americas, while ginger was not native, it was quickly adopted after being introduced by European colonizers. By the 18th century, ginger was being cultivated in Jamaica and other Caribbean islands, where it became integrated into local healing traditions for treating colds, digestive issues, and pain. Traditional Caribbean medicine used ginger tea as a remedy for menstrual cramps, nausea, and fever.

In traditional Japanese and Korean medicine, ginger (shoga in Japanese) was used to improve circulation, reduce nausea, and treat cold-induced ailments. Japanese folk medicine particularly valued ginger for its warming properties during winter months and for preventing motion sickness during sea travel. Throughout Southeast Asia, particularly in Thailand, Indonesia, and Malaysia, ginger has been a staple in traditional healing systems for millennia. It was commonly used in postpartum care to warm the body, stimulate recovery, and promote lactation.

In these traditions, ginger was often combined with other herbs in complex formulations tailored to specific conditions. The concentrated essential oil and standardized extracts of ginger, as used in modern supplements, are relatively recent developments, becoming popular in the late 20th century as interest in evidence-based natural medicine grew. Traditional uses focused more on the whole root, infused oils, and water extracts (teas). The scientific validation of many traditional uses of ginger, particularly for nausea, inflammation, and pain, has helped bridge traditional knowledge with modern pharmacological understanding, making ginger one of the most thoroughly researched medicinal plants with applications spanning ancient and contemporary healing systems.

Viljoen, E., et al. (2014). A systematic review and meta-analysis of the effect and safety of ginger in the treatment of pregnancy-associated nausea and vomiting. Nutrition Journal, 13, 20. doi:10.1186/1475-2891-13-20, Bartels, E.M., et al. (2015). Efficacy and safety of ginger in osteoarthritis patients: a meta-analysis of randomized placebo-controlled trials. Osteoarthritis and Cartilage, 23(1), 13-21. doi:10.1016/j.joca.2014.09.024, Marx, W., et al. (2017). Ginger-Mechanism of action in chemotherapy-induced nausea and vomiting: A review. Critical Reviews in Food Science and Nutrition, 57(1), 141-146. doi:10.1080/10408398.2013.865590, Zhu, J., et al. (2018). The efficacy of ginger for the prevention of postoperative nausea and vomiting: A meta-analysis. PLoS One, 13(10), e0204729. doi:10.1371/journal.pone.0204729, Jafarnejad, S., et al. (2017). Effect of ginger (Zingiber officinale) on blood glucose and lipid concentrations in diabetic and hyperlipidemic subjects: A meta-analysis of randomized controlled trials. Journal of Functional Foods, 29, 127-134. doi:10.1016/j.jff.2016.12.006

Ginger extract for chemotherapy-induced nausea and vomiting in breast cancer patients (ClinicalTrials.gov Identifier: NCT03643731), Effects of ginger supplementation on inflammatory biomarkers in patients with type 2 diabetes (ClinicalTrials.gov Identifier: NCT04099407), Ginger for prevention of delayed chemotherapy-induced nausea and vomiting (EudraCT Number: 2020-001456-18), Efficacy of ginger extract in reducing pain and improving function in knee osteoarthritis: A randomized controlled trial (ISRCTN Registry: ISRCTN15937589), Ginger supplementation for cognitive function in older adults with mild cognitive impairment (ClinicalTrials.gov Identifier: NCT04523389)