Exploring the Complexities and Caveats of Safe Internal Use of Essential Oils for Pain:
Highlighting Intestinal Discomfort, Part 2
By Sarah A. LoBisco, ND, IFMCP
Editor note: Part 1 of this article, published in December 2018, discusses issues of safety, essential oil quality, metabolism, and synergy when using essential oils orally. Part 2 looks at the clinical application of ingested essential oils for intestinal discomfort.
Before selecting a therapeutic modality of any kind, it is important to address the underlying cause and use a naturopathic and functional medicine approach to address it. I would be amiss to not briefly review some preliminary considerations for using essential oils.
For intestinal discomfort and symptoms, an integrative doctor will want to take a full history, perform a physical exam, and run the appropriate tests. Examples of laboratory assessments include imaging for detecting pathology and functional issues, assimilation and absorption markers (e.g., pancreatic elastase, products of protein breakdown, fecal fats), excess inflammatory indicators (e.g., calprotectin, eosinophil protein X (EPX), lactoferrin), a Celiac panel, SIBO breath test, markers for bacterial, viral, fungal, and parasitic overgrowth, and microbiota panels.
A “Five R” program for restoring and healing a diseased gastrointestinal tract is the preferred protocol in functional medicine, but the aspects are likely be implemented by most integrative practitioners. These Five R’s are the following:
1. Removing the cause and contributors (i.e., dietary, microbes, or environmental),
2. Replacing the nutrients that are needed for assimilation and digestion,
3. Repairing the damage to the gut,
4. Re-inoculating the good bacteria, and
5. Rebalancing lifestyle factors (sleep, stress, exercise) that can perpetuate a dysfunctional gut.(122-124)
Oral Use of Essential Oils for Intestinal Discomfort
Now, I will start the discussion on the “nuts and bolts” of internal administration of essential oils for gut discomfort. I will review the evidence in the research for the use of the most common essential oils for intestinal health and those that I personally use in my practice. I will also provide dosages, if available, that are recommended from scientific reviews and experts. Next, I will give a summary on essential oils’ antimicrobial effects and their impact on the microbiome. Finally, I will give a synopsis of how I would incorporate these essential oils in my practice.
Despite the controversary surrounding oral application of essential oils, many practitioners are already currently administrating two essential oils for gut comfort without concern. Many practitioners who run the previously mentioned lab markers have witnessed that certain essential oils are deemed “sensitive” to dysbiosis markers on various functional gastrointestinal health panels. For this reason, many functional and naturopathic medicine practitioners have experience administering the essential oils of oregano for its antimicrobial properties(124-127) and enteric coated peppermint oil for irritable bowels.(128-132) Two additional essential oils I personally use in my practice are fennel and ginger. Please refer back to the previous section (Part 1) on “Internal Usage of Essential Oils: Controversy, Scare Tactics, and Bad Science” in which I highlighted the benefits of fennel oil for gut distress and its safe internal use.
There is also one proprietary blend I have found to be very clinically effective.
Peppermint is perhaps the most researched and clinically evaluated essential oil used for intestinal discomfort. It has even been validated in several trials for its efficacy in IBS subjects.(128-131)
Peppermint’s mechanism of action on pain has been studied but is not conclusive. It may be related its impact on TRPM8, a transient receptor potential (TRP) cation channel. This receptor has been found to be activated by cold temperatures and menthol, a main constituent found in peppermint essential oil. It induces smooth muscle contractions inversely relational to stimulation (temperature) and initiation of Rho-kinase. This leads to smooth muscle contraction. Furthermore, there is some controversial evidence that menthol modulates intracellular calcium stores. In summary, peppermint oil may relieve intestinal discomfort through activation of TRPM, modulating calcium stores, and stimulation of menthol.(129)
There is a safety precaution reported in the literature that peppermint may delay gallbladder emptying. The evidence cited for this is based on one study of 12 healthy volunteers that was assessing gastrointestinal motality.(128, 130-131)
In this experiment, the researchers compared the effects of a combination of 90 mg of peppermint oil in 50 mg of caraway oil to a proprietary formulation to two medications and a placebo that contained NaCl (salt). The participants were tested at baseline and after drinking apple juice at various time intervals. The authors simultaneously measured gastric and gall-bladder emptying ultrasonically and orocaecal transit time using the H2 breath test using lactulose.(128) The authors concluded the following:
I take issue to making this safety flag for peppermint oil based on twelve healthy volunteers. Under normal conditions, fatty acids stimulate gallbladder contraction. The test drink was a non-fat juice, so how could the gallbladder be stimulated? Still, according to the Expanded Commission E, the following contraindications are reported: “Obstruction of bile ducts, gallbladder inflammation, severe liver damage. In case of gallstones, to be used only after consultation with a physician. Preparations containing peppermint oil should not be used on the face, particularly the nose, of infants and small children.”(132)
I believe that due to the impressive clinical trials that report the efficacy of peppermint for IBS, it may be a better conclusion that it is a modulator of digestive function rather than an inhibitor or stimulator of motility. Furthermore, with appropriate dosage, clinicians should not dismiss this essential oil for fear of harm.
Oregano Essential Oil
Whereas ingestion of peppermint oil has many clinical trials of efficacy for assisting with digestive distress, oregano oil does not. Yet, it is one of the go-to essential oils for most practitioners in treating gut discomfort related to microbial imbalances. Interestingly, clinical trials on efficacy regarding the popular use for intestinal dysbiosis is lacking.(133,134) There is one lone study on inhibition of enteric parasites.(125)
Its isolated compound, carvacrol, was found in vivo to have protective effects against clostridium difficile associated dirrahea.(135) In another in vivo model using pigs, oregano oil was found to improve intestinal permeability via modulating bacteria and immune status. Interestingly, the oregano oil used, as reported in the analysis found within the supplementary materials, did not contain the two components considered to be most active.(136) Many manufactured oregano oil products are encapsulated and standardized to carvacrol and thymol.
Still, clinicians report benefits and improvements of markers of intestinal dysbiosis for their patients.
As far as safety, it is recommended to be diluted in a fatty oil due to its potentially corrosive properties.
Ginger Essential Oil
Ginger is another well-known herb for its digestive properties and alleviating discomfort. It has evidence of this from a few human trials and many in vitro and in vivo.(137-142) In vitro and vivo, ginger oil has been shown to be microbe inhibiting and have inflammatory modulating properties. The constituents of ginger oil have also shown to be stomach protective,(139) possess antioxidant properties, and modulate inflammation.(137-142)
One study review of five trials had compelling evidence that the inhalation of a combination of peppermint oil and ginger oil could assist with nausea, though some methodical issues were reported. The authors stated, “Their results suggest that the inhaled vapor of peppermint or ginger essential oils not only reduced the incidence and severity of nausea and vomiting but also decreased antiemetic requirements and consequently improved patient satisfaction.”(142)
Cumin Essential Oil
Cumin essential oil is another essential oil traditionally used for digestive health. A small pilot trial with 57 subjects diagnosed with IBS using ROME II criteria assessed the efficacy of 2% cumin essential oil and had an impressive outcome. The essential oil was administered as 10 drops twice daily for four weeks. The authors concluded, “Abdominal pain, bloating, incomplete defecation, fecal urgency and presence of mucus discharge in stool were statistically significant decreased during and after treatment with Cumin extract. Stool consistency and defecation frequency were also both statistically significant improved in patients with constipation dominant pattern of IBS.”(143)
I have had success using combinations of essential oils in proprietary formulations for intestinal health promotion and relief of irritation. One essential oil blend I routinely use contains the following single oils with evidence of digestive support: Artemisia dracunculus (tarragon) oil,(144) Zingiber officinale (ginger) root oil,(137-142) Mentha piperita (peppermint) oil,(128-132) Juniperus osteosperma (juniper) oil,(145) Foeniculum vulgare (fennel) oil,(110-114) Cymbopogon flexuosus (lemongrass) oil,(146-149) Pimpinella anisum (anise) seed oil,(150) and Pogostemon cablin (patchouli) oil.
This has been very effective in my practice for relief of gastrointestinal discomfort and symptoms. Most report improvement within one month. This is likely due to the synergistic components of the essential oils.(77-78)
Dilution and Dosages: A Guide for Essential Oils
Now that I’ve reviewed the evidence that ingesting essential oils and that their use for intestinal discomfort is science-based, I will now discuss specific dosage guidelines. Although aromatherapists have different viewpoints on dilution amounts necessary for safe application, measurement for what constituents a single dose is a commonality.
In this section, I will provide a dosage guide compiled from the experience of experts and various merchandizers.**
Most essential oils come in 5 ml and 10 ml bottles. This equates to approximately 100 and 300 drops respectively. A general knowledge of equivalency from drops to measurements is necessary for the practitioner to understand, as most often dosage is based on drops rather than liquid measurements of essential oils. Please see Table 1 (below) for these conversions and dilutions of essential oils (EOs).(117-121)
What the Science Says: Internal Usage and Conversion Measurements for the Application of Essential Oils
With knowledge of which essential oils to use for abdominal pain and a tool for conversions for dosages for administration, I will now review what is in the literature for internal adminstration of these selected essential oils.
Peppermint Essential Oil
According to Examine, the dosage for peppermint essential oil “does not follow a particular dosage,”(131) but is often standardized for menthol content. Quality and standards are once again validated as imperative for efficacy by this review. The authors summarize the research on this oil’s administration as follows:
The American Botanical Council’s Expanded German E Commission on peppermint further validates this reported dosage and administration.(132) It states:
The German E Commission has more specific quality and internal standards for essential oils than found in the United States. It reports on the constituents and their percentages that must be contained for a bottle of peppermint essential oil to be considered pharmaceutical grade, beyond menthol:
An example of how to use Table 1 for converting the .1-.2 ml indicated dosage to drops of essential oils is as follows:
· .2 ml of peppermint oil equates to approximately .067 oz (1 oz =30 ml).
· There are 600 drops of essential oil in one ounce.
· .067 oz of 600 drops totals approximately one drop two to three times a day. This equates to six to 12 drops per day.
Fennel Essential Oil
The American Botanical Council’s Expanded German E Commission reports on the dosage and administration for fennel essential oil(110) as follows:
Other sources do not contain direct references to dosage.
Oregano Essential Oil
Examine states the following regarding dosage for oregano oil:
Since the study cited is based on an emulsified oil, not an essential oil, this information is misleading.(133) Using Table 1:
· 1 drop = 30 mg.
· The dosage reported would be 600 mg/30 mg, which would equate to 20 drops of pure essential oil. This is not an ideal dose.(133, 134)
I did find one human trial of 104 subjects that used oregano oil in a formulation. The study found the efficacy of herbal treatment to be equivalent to Rifaximin for treatment of SIBO. For the intervention, one of the two formulations randomized contained .1 ml of oregano oil. This would be equivalent to approximately .5-1 drop of oregano oil.(151)
Ginger Essential Oil
Neither of the monographs for ginger in Examine(152) and the American Botanical Council’s Expanded German E Commission(153) state a dosage for the internal usage of essential oil of ginger, as they do the herb. Natural Medicines Database authors report on nasocutaneous administration and inhalation of ginger oil as follows:
The conversion of drops of essential oil in a 5% solution of ginger oil would be as follows:
· 1 oz. = 600 drops
· 6 drops of EO per oz. of carrier oil = 1% dilution (1% of 600 drops)
· 30 drops of EO per oz. of carrier oil= 5% dilution (5% of 600 drops)
Essential Oils and the Microbiome
Since healing the intestinal tract via the “Five R” program includes removing the cause (e.g., microbes) and re-inoculating the good bacteria, it is important to pause and discuss how essential oils, which are often deemed “antimicrobial,” impact the microbiome. From my research and experience, I believe that high quality essential oils likely balance microbe activity. Specifically, there is supporting evidence that as they eliminate overgrowth, they also spare commensal organisms and protect our tissues.
I will now provide a brief review of the scientific literature regarding this topic. First, I will give a quick summary on their antimicrobial actions and use with antibiotics. Then, I will provide the compelling vivo and in vitro trials. This, in combination with years of clinical experience and experts’ opinions, provides support for assisting with positively balancing the intestinal microbiome.
The Antimicrobial Properties of Essential Oils
The antimicrobial activity of essential oils on pathogenic bacteria is diverse. In a review on the effects, the authors differentiate the actions of essential oils (EOs) to their isolates. The authors state:
A proposed mechanism of essential oils on microbe destruction consists of their toxic effects on membrane structure. These include “degradation of the cell wall, damaging the cytoplasmic membrane, cytoplasm coagulation, damaging membrane proteins, increased permeability leading to leakage of cell contents, reducing proton motive force, reducing intracellular ATP pool via decreased ATP synthesis and augmented hydrolysis that is separate from the increased membrane permeability and reducing membrane potential via increased membrane permeability.”(155)
Essential oils have also been reported to interfere with quorum sensing (bacteria’s regulation of gene expression related to changes in cell-population density) and decrease bacterial virulence factors.(155)
They may also be helpful in combination with antibiotics to prevent resistance. In a 2014 article titled, “Essential Oils, A New Horizon in Combating Bacterial Antibiotic Resistance,” the authors explain that essential oils’ versatile properties make them a novel approach for a “drug compound.” This is because essential oils have more than one therapeutic effect due to their many biological impacts. This contrasts with a drug’s mechanism which is skewed to act on one pathway in the body, not accounting for effects on the body’s other functions. The article states:
Essential Oils Impact on Intestinal Microbes In Vitro
An in vitro study with eight essential oils, the authors sought to determine if essential oils selectively inhibited several microbes that cause intestinal dysbiosis while sparing 12 species of intestinal bacteria. The authors reported:(157)
In a study with swine cecal digesta, the authors tested the antimicrobial effects of 66 essential oils and their impact on swine gut. The authors stated:
Essential Oils Impact on Intestinal Flora In Vivo
In a 2010 in vivo study, it was demonstrated that ocotea essential oil inhibited inflammatory mediators from microbial byproducts while simultaneously protecting the gastric mucosa of rodents.(159)
In another study with rabbits, thyme oil increased antioxidant status (i.e., GPx activity) and decreased oxidative harm (i.e., lowered malondialdehyde) in the small intestine. It also positively influenced intestinal integrity, aka preventing “leaky gut,” as measured by transepithelial electrical resistance (TEER). Furthermore, there was a tendency “for thyme oil to stimulate the abundance of some microbes beneficial in the rabbit gut.” The abstract states:(160)
A study in chickens demonstrated that five culinary herbs and their essential oils (thyme, oregano, marjoram, rosemary, and yarrow) had negligible effects on gut microflora and beneficially impacted these broiler chicks’ digestion. In the experiment, body mass and feed consumption were measured on a weekly basis. Counts of lactic acid bacteria, coliforms, anaerobes, and Clostridum perfingens were assessed at 25 days. Finally, digestibilities were measured via nitrogen (N), dry matter (DM) and organic matter, and sialic acid concentration. The researchers concluded:(161)
My Clinical Experience:
How I Use Essential Oils Internally for Intestinal Discomfort
I find oral administration of essential oils the most effective method of application for clients that are seeking relief from symptoms of irritable bowel syndrome, functional gastrointestinal disorders, bloating and abdominal extension, food poisoning (due to antimicrobial effects noted above), discomfort, gas, dysbiosis, and changes in stool frequency.
I instruct my clients to administer one to two drops of the selected essential oil from a quality supplier. The drops are placed in a vegetable capsule (enteric coated) using pipette droppers. Next, they are asked to fill the remainder of the cap with coconut oil or a non-dairy milk substitute. This is important for sensitive patients, as it will provide coating for the stomach.
Essential oils are alternated every two months or until symptoms have resolved and lab markers are back within normal ranges. I also recommend that my clients take 1-2 days off per week depending on tolerance. If one experiences burping, GI discomfort, or notices loose stools, I will decrease the dose.
I often supplement any gut protocol with a relaxing essential oil to restore the nervous system. The most well-known and most researched essential oil for this is lavender.(162-167)
Lavender has a good reputation for alleviating anxiety Europe. Germany has authorized a preparation of lavender oil, Silexan, for treatment of restlessness during anxious mood.(162-167) It is branded as LASEA and is standardized for 20-45% linalool and 25-46% linalyl acetate.(162) Two trials have indicated that Silexan has been effective in mood related issues without unwanted sedative effects.(165,166) According to Examine, “It is prescribed (or at least used) for Generalized Anxiety disorder in Germany without apparent benzodiazepene actions.”(163)
In a comprehensive review, the nervous system effects of lavender were analyzed in animal and human clinical trials. The authors reported that lavender was shown to have in vivo effects of modulating inflammatory pathways in the brain and on the neurotransmitters dopamine, GABA and serotonin. Human studies with functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) also indicated brain imaging evidence for relaxation effects. These calming effects were also shown to have an impact on sleep, pain, and positive mood.(167)
These psychoneurological effects will impact gastrointestinal function related to the gut-brain connection, stress, and resultant discomfort and pain.(168)
As far as dosage, both Examine and the American Botanical Council’s Herbal Expanded Commission E Commissions report that the internal dosage of lavender oil is between 80-160 mg of essential oil.(162,163) Using the conversions in the table:
· 30 mg = approximately 1 drop of oil
· 80-160 mg would be approximately 3-6 drops of lavender oil
I have often also used this oil internally at these dosages for clients who appear to have hyperactive sympathetic activity, which is most of my IBS and pain clients.
Summarizing the Art and Science of Selecting the “Correct” Essential Oil
Essential oils can effectively remove the obstacles in the way of healing via their multimodal effects while simultaneously and synergistically working with the body to bring it to balance. This is due to their biochemical constituents affecting physiology combined with the instantaneous psychological effect of their aroma.(1-2)
Not only are essential oils synergistic within themselves and with other modalities, they are also the same regarding their action with the human body. One human study provided evidence that the metabolomics and biochemical pathways of individuals were modulated differently by the same essential oil intervention.
In the clinical trial, researchers sought to determine the metabolic changes in thirty-one females with mild anxiety symptoms after exposure to aroma inhalation for 10 days. In several participants, no effect was found in the measurements studied, yet there were minimal disturbances and many benefits reported by all the responsive subjects. This demonstrates the mechanisms of essential oils “innate wisdom” to bring about balance to the human body. The authors concluded:(169)
I have now provided evidence that essential oils can address underlying causes of dysfunction while simultaneously alleviating contributors, triggers, and mediators. I have shown this through the example of using them internally for intestinal discomfort. By reviewing what I have learned and my clinical experience for the past seventeen years, my hope is that now clinicians can decipher how to proceed with more informed, safe, and confident decisions on dosage and proper use of this powerful, ancient, innately intelligent, healing modality.
Sarah LoBisco, ND, is a graduate of the University of Bridgeport's College of Naturopathic Medicine (UBCNM). She is licensed in Vermont as a naturopathic doctor and holds a bachelor of psychology degree from State University of New York at Geneseo. Dr. LoBisco is a speaker on integrative health, has several publications, and has earned her certification in functional medicine. Dr. LoBisco currently incorporates her training as a naturopathic doctor and functional medicine practitioner through writing, researching, private practice, and her independent contracting work for companies regarding supplements, nutraceuticals, essential oils, and medical foods. Dr. LoBisco also enjoys continuing to educate and empower her readers through her blogs and social media. Her recent blog can be found at www.dr-lobisco.com.