Terpenes are a large and diverse class of organic compounds naturally produced by plants, often recognized as the fragrant, oily molecules that give plants their distinct aromas and flavors. These compounds serve various purposes in the plant world, from attracting pollinators to deterring predators. Research suggests that certain terpenes and closely related phytochemicals can interact with the human body in ways that may alleviate common ailments, including nausea. This article explores specific terpenes that show promise in calming the gastrointestinal distress and neurological signaling associated with queasiness.
How Terpenes Interact with Nausea Pathways
The sensation of nausea and the resulting vomiting reflex are complex processes involving the brain, the gut, and the nervous system that links them. Many terpenes exert their anti-nausea influence by modulating key neurotransmitter systems involved in this communication loop. One significant pathway involves the 5-hydroxytryptamine type 3 (5-HT3) serotonin receptors, which are located both in the brain and on the vagal afferent nerves lining the gastrointestinal tract.
Serotonin is released from specialized cells in the gut in response to irritants or toxins, activating these 5-HT3 receptors and sending a signal to the brain’s vomiting center. Certain plant compounds, such as the gingerols and shogaols found in ginger, function as antagonists to the 5-HT3 receptor. They effectively block this nausea-inducing signal from the gut to the brain, helping to interrupt the body’s reflexive response.
Another mechanism involves the endocannabinoid system (ECS), a regulatory network that plays a role in controlling gut functions, pain, and the emetic reflex. Activating the ECS, particularly the CB1 receptor, has been shown to suppress vomiting. While classical terpenes do not directly bind to this receptor, their indirect influence can contribute to overall symptom relief. Compounds with muscle-relaxing properties can also act directly on the gut, reducing the spasms and excessive contractions that frequently accompany feelings of sickness.
Specific Terpenes Recommended for Nausea Relief
Limonene
Limonene is a monoterpene found in high concentrations in the peels of citrus fruits, including oranges, lemons, and mandarins. This compound is studied for its gastroprotective properties and is believed to aid in relieving symptoms of heartburn and acid reflux by neutralizing gastric acid.
Limonene also supports normal peristalsis, the rhythmic muscular contractions that move food through the digestive tract. By regulating gut motility and reducing gastric acid irritation, limonene addresses common physical triggers of mild nausea. Its bright, refreshing aroma is an added benefit that can help distract from feelings of queasiness.
Beta-Caryophyllene
Beta-caryophyllene (BCP) is a sesquiterpene found abundantly in spices like black pepper, cloves, and rosemary. It is unique among terpenes because it acts as a selective full agonist of the Cannabinoid Receptor type 2 (CB2). The CB2 receptor is associated with controlling inflammation and pain, particularly outside of the central nervous system.
By activating the CB2 receptor, BCP can induce anti-inflammatory and anxiolytic effects. These effects are beneficial in cases where nausea is exacerbated by stress or gut inflammation. Unlike compounds that activate the CB1 receptor, BCP does not produce psychoactive effects.
Linalool
Linalool is a terpene alcohol found in over 200 plant species, most notably lavender, basil, and coriander. Its primary mechanism of action is related to its calming and sedative properties, which can indirectly alleviate nausea caused by anxiety or stress. Linalool interacts with the central nervous system, modulating activity through the GABAergic system.
The calming effect of linalool also translates into muscle-relaxing properties, which may help to soothe gut discomfort or spasms. Studies utilizing lavender oil, which is rich in linalool, have demonstrated a significant reduction in post-operative nausea and vomiting. This suggests its use in aromatherapy is effective for acute symptoms.
Gingerols and Shogaols
While not strictly classified as terpenes, the pungent compounds in ginger—gingerols and shogaols—are highly relevant due to their potent antiemetic action. These compounds are major components of the ginger rhizome and work by modulating the 5-HT3 serotonin receptors. They directly inhibit the activation of these receptors, preventing the initiation of the vomiting reflex.
Ginger’s active compounds also influence gut function by increasing gastric tone and accelerating gastric emptying. This peripheral action in the digestive tract, combined with their anti-serotonin effect, makes ginger a widely recognized remedy for multiple forms of nausea, including motion sickness and morning sickness.
Sourcing and Safe Use
Terpenes can be utilized for nausea relief through several administration methods, depending on the source material. One common and fast-acting method is aromatherapy, or inhalation, which involves using essential oils containing the desired compounds. Inhaling the vaporized oil allows the molecules to quickly reach the olfactory system and central nervous system.
Whole-plant ingestion is a reliable method for administering compounds like gingerols and shogaols, such as drinking ginger tea or consuming a ginger chew. For terpenes like limonene, consuming the zest of fresh citrus fruits or using food-grade extracts can be effective. Essential oils can also be applied topically when diluted in a carrier oil, such as rubbing a diluted blend onto the abdomen or pulse points.
Safety is a primary consideration: essential oils should not be ingested unless specifically directed by a healthcare provider, as some undiluted oils can be toxic. For topical use, proper dilution with a carrier oil is necessary to prevent skin irritation. Since persistent or severe nausea can be a symptom of a serious underlying condition, it is important to consult with a healthcare professional to determine the cause and safe course of treatment.