Background
Of particular interest to many–especially the millions around the world who suffer from digestive issues–is the relationship between D-Limonene and acid reflux. Can D-limonene reduce or even eliminate heartburn, GERD and acid reflux? Is it a practical alternative to antacids and PPIs (proton pump inhibitors). Read on…
What is D-Limonene?
D-Limonene is a natural chemical that is found in several citrus oils. It is typically extracted from citrus fruit peels, either through cold pressing or steam distillation. According to the FDA, it is “Generally Recognized as Safe” ingredient, which is the highest level of safety that the FDA recognizes. It is used as a flavoring agent in many foods. Indeed, there does not appear to be a known toxic limit for humans: In one clinical trial, 5 males were given 20 grams of d-limonene (considered a very high dose) and the only side effect was that some experienced slight watery stools (Sun 2007). D-limonene has also been shown to have a variety of medicinal benefits, such as dissolving gallstones and acting as a mild appetite suppressant. It is considered to have anti-oxidant and anti-inflammatory properties.
What does the science say?
Anecdotal evidence of the compound’s use in reducing heartburn goes back many hundreds of years, but it has not been until recently that scientific studies have started to confirm the compounds ability to assist with the prevention of ulcers and in reducing Gastroesophageal Reflux Disease (GERD, or chronic heart burn). Enthusiasm among both patients and doctors is rising concerning the use of D-Limonene, as the short- and long-term effects of Proton Pump Inhibitors (PPIs) are being better recognized and understood.
Current literature indicates that the oil can be very effective at preventing gastric ulcers due to both alcohol consumption (ethanol) and Non-Steroidal Anti-inflammatory Drugs (NSAIDs) (Rossa et al. 2001). D-Limonene has also been shown in several controlled studies to similarly affect heart burn. According to the patent application by Wilkins (2002), 19 participants with heartburn and GERD lasting more than 5 years were asked to discontinue their current treatments and take 1 capsule containing 1,000mg of D-limonene every day or every other day. By day two, 32% of them reported relief, and by day fourteen, 89% reported relief from heartburn symptoms.
In another study presented in the same paper, 13 individuals participated n a double-blind, placebo-controlled clinical trial on the effects of D-limonene on acid reflux. After 14 days, 89% of the D-Limonene group reported relief, while only 29% of the placebo group experienced the same. Lastly, in an unpublished study (reported by Werback, 2008) with 22 participants in a double-blind, placebo-controlled trial, 75% of the D-Limonene group reported relief after 2 weeks, with only 20% of the placebo group seeing the same results. In all studies, no negative effects of taking 1,000 mg of D-Limonene were observed. Although, at the time of these studies, Wilkins reported that “the mechanism of action is not certain,” he suspected that D-Limonene played a role in protecting the mucosal lining and allowing proper gut movement (peristalsis).
This hypothesis was later supported by several other studies. This included Rossa, et al. (2001), which examined the evidence from several studies and concluded that D-limonene is important in the production of the mucous lining of the stomach and GI tract. Besides mucous, Rossa notes that the GI tract contains a bicarbonate-phospholipid barrier which both physically and chemically protects the cells lining the stomach and intestines, and also prevents bacterial growth and infections. When this mucous layer is compromised either by removal or by dissolution from ethanol, NSAIDs or other ulcer inducing agents, it can result in both ulcers and heartburn. D-limonene, it is thought, protects and helps regenerate this layer.
Thiss effect on the mucousal layer by d-limonene was also shown in a 2001 rat study by Rossa et al., in which the experimental group was treated with D-Limonene prior to ingestion of pure ethanol. The control group of rats was treated with carbenoxolone (a popular anti-ulcer drug). In the group treated with D-Limonene, there was 100% gastro-protection, and in the carbenoxolone group only 85% protection. When the same experiment was done with NSAIDs instead of alcohol, similar results were found, with a 51% increase in protection in the D-limonene group from the formation of gastric ulcers related to NSAIDs. Moraes, et al. (2009) confrimed these findings by looking at lesions present following the ingestion of alcohol of NSAIDs in a separate study. That study also concluded that the mechanism of action of D-limonene was not to reduce the amount of acid in the stomach as with PPIs, but by supporting the secretion and proper composition of the protective mucous barrier of the stomach and GI Tract.
CONCLUSION
Today there are many thousands of individuals who have reported that their heartburn, acid reflux or GERD are in remission thanks to D-limonene. Despite these anecdotes and the positive results of the limited clinical trials and studies reported above, more research needs to be done to determine best protocols and to gauge the level of protection afforded by D-limonene.
D-limomene is a dietary supplement, so it can be purchased without a prescription. Though it is considered safe, you should consult with your medical professional if you have any question about its usage and whether it’s a good course of action for you.
REFERENCES:
Moraes T., Kushima H., Molerio F. C. et al. (2009) Effects of limonene and essential oil from Citrus aurantium on gastric mucosa: Role of prostaglandins and gastric mucus secretion. Chemico-biological Interactions 180:3, (499-505). DOI:10.1016/j.cbi.2009.04.006. https://www.researchgate.net/publication/24397368_Effects_of_limonene_and_essential_oil_from_Citrus_aurantium_on_gastric_mucosa_Role_of_prostaglandins_and_gastric_mucus_secretion
Rozza A.L., de Mello T., Kushima H., Tanimoto A., et. Al. (2001) Gastroprotective mechanisms of Citrus lemon (Rutaceae) essential oil and its majority compounds limonene and-pinene: Involvement of heat-shockprotein-70, vasoactive intestinal peptide, glutathione, sulfhydryl compounds, nitric oxide and prostaglandin E2. Chemico-Biological Interactions. 189 (82-89). https://s3.amazonaws.com/academia.edu.documents/46024249/Gastroprotective_mechanisms_of_Citrus_le20160528-26115-1e4c23y.pdf?response-content-disposition=inline%3B%20filename%3DGastroprotective_mechanisms_of_Citrus_le.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWOWYYGZ2Y53UL3A%2F20190716%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20190716T012319Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=a343607cfd3d8c6370164202f8ae37d5835cffe48b8720e0c0122184a49d06b5
Sun J. (2007) D-Limonene: Safety and Clinical Applications. Alternative Medicine Review. 12:3 (259-264). https://pdfs.semanticscholar.org/51a9/a107c4bea94b31311f77d446e941fa98a94d.pdf
Werback M.R. (2008) Melatonin for the Treatment of Gastroesophageal Reflux Disease. Alternate Therapies, 14:4 (54-58) .http://www.encognitive.com/files/MELATONIN%20FOR%20THE%20TREATMENT%20OF%20GASTROESOPHAGEAL%20REFLUX%20DISEASE.pdf
Wilkins J Jr (2002) Method for treating gastrointestinal disorder. U.S. 19.Patent (642045). https://patents.google.com/patent/US6420435