Fennel Seed as a Heartburn Remedy – Does It Work?
As part of our ever-growing database on heartburn remedies, in this article we will be reviewing the research on fennel and its possible effects on acid reflux.
If you are unfamiliar with it, seeds of this herb are a popular supplement and have been increasingly recommended as a popular home heartburn remedy.
Below, you will find out exactly what fennel seed is, how it works, and if it is an effective heartburn remedy.
Fennel Seed – What Is It?
Fennel is a flowering herb that has been introduced to many parts of the world and is a common supplement. In most supplements, an extract of oil is taken from its seeds.
This oil has been the subject of some studies, particularly examining its effects on the digestive tract.
Fennel Seed As a Heartburn Remedy – What the Research Says
Unfortunately, I have been unable to find any direct research on the usage of fennel or fennel oils for the reduction of heartburn. There are a lot of claims out there boasting about the heartburn-fighting effects of fennel but there is no research to support this conclusion.
However, this does not necessarily rule out fennel as a heartburn remedy. While we do not have any direct evidence, we can examine the indirect evidence.
Fennel Seed’s Effects on Digestion
While no research links heartburn relief to fennel seed supplementation, there are a few studies out there on the effects of fennel seed on the digestive tract. In particular, fennel has commonly been used to treat infant colic and adult constipation.
Before you think that these two problems have nothing to do with acid reflux, GERD, and heartburn, you should know that irregularities in digestive tract motility (movement of food along the digestive tract) are strongly associated with acid reflux.
In other words, slow or impaired motility not only leads to constipation but may also lead to acid reflux (1). Anything that improves constipation may improve reflux as well.
If you are unfamiliar with infant colic, it simply refers to frequent, lengthy bouts of unexplained crying in infants. While the exact cause of colic is unknown, many physicians believe it is related to poor digestion or digestive pains.
Fennel seed is commonly recommended as a natural treatment for this condition. One study examined the efficacy of fennel seed oil for this purpose; researchers reported that 65% of treated infants has complete elimination of colic, which is an incredible success rate (2).
While this result does not tell us exactly what fennel seed does, the study does tell us that if colic is indeed the result of a digestive tract irregularity, then fennel seed oil is beneficial.
Also, it is likely that there are multiple causes of colic. Naturally, pinpointing the exact cause of crying is difficult in babies cannot tell us what is wrong and that most babies usually outgrow colic within a few months. It is possible that the some of the remaining 35% of babies who did not improve had colic for some other reason than digestive problems.
I was able to find two studies on adult constipation and fennel oil. Both of these effects studied the effects of herbal concoctions (both containing fennel) on adult constipation. While one study was performed in adults and one on the elderly, both reported significant improvements in constipation on groups that supplemented with the studied herbs (3, 4).
The only downside to these studies is that multiple herbs were used that included fennel seeds. As a result, any positive effect on constipation may have been due to other herbs. As a result, these studies are a wash.
Effect of Fennel Seed Oil on Smooth Muscle
Perhaps the most interesting study of the lot was one that examined the effects of different herb oils on the contraction of the smooth muscle of the ileum (part of the small intestine) and trachea.
This particular discovery found that the consumption of fennel seed oil, unlike most of the oils studied) led to increased phasic contractions of the ileal muscle (5).
To simplify the results, the researchers report that fennel oil appears to make the small intestine contract more frequently, which would propel food along the intestinal tract at a faster rate.
Since better digestive motility is associated with lower instances of acid reflux and constipation, this could not only explain why fennel seed is effective at relieving constipation and colic but also why it has anecdotally been reported to relieve heartburn.
However, this study was conducted in gerbils, not humans. We cannot know for sure what the exact effect of fennel in humans is until more research is performed, but given its positive effects on constipation and colic, it may indeed improve gastric motility and reduce colic.
Fennel Seed as a Heartburn Remedy – The Bottom Line
After looking through the research, I think that this supplement may indeed benefit those with GERD and acid reflux, particularly if other digestive problems such as constipation are present.
Unlike many other supplement and medications, researchers in all 3 studies mentioned in this article reported no side effects as a result of fennel supplementation among participants (3, 4, 5). While it is within the realm of possibility that there may be undiscovered side effects or a rare allergic reaction, current research reports that it is generally recognized as safe.
The bottom line with fennel seed as a heartburn remedy is that the research looks promising, but the evidence is only indirect.
However, given that fennel seed supplements are not exactly an incredibly profitable industry, it is unlikely that any amount of research will be performed on fennel seed and acid reflux anytime soon.
Be sure to mention fennel seed supplementation to your doctor before you try it out, particularly if you take any other prescription medication (particularly birth control or other hormonal medications), have a history of seizures, or have plant allergies.
The only way to know for sure if this will work for you is to try it out. If you shop online, you can get a few month’s supply for under 10$, so it is not a huge investment by any means.
1. Kamiya T, Adachi H, Joh T. Relationship between gastric motility and the pathophysiology of GERD. Nippon Rinsho. 2007 May;65(5):836-9.
2. Alexandrovich I, Rakovitskaya O, Kolmo E, Sidorova T, Shushunov S. The effect of fennel (Foeniculum Vulgare) seed oil emulsion in infantile colic: a randomized, placebo-controlled study. Altern Ther Health Med. 2003 Jul-Aug;9(4):58-61.
3. Picon, P.D., et al. Randomized clinical trial of a phytotherapic compound containing Pimpinella anisum, Foeniculum vulgare, Sambucus nigra, and Cassia augustifolia for chronic constipation. BMC Complement Altern Med. 2010 Apr 30;10:17.
4. Bub S, Brinckmann J, Cicconetti G, Valentine B. Efficacy of an herbal dietary supplement (Smooth Move) in the management of constipation in nursing home residents: A randomized, double-blind, placebo-controlled study. J Am Med Dir Assoc. 2006 Nov;7(9):556-61.
5. Reiter M, & Brandt W. Relaxant effects on tracheal and ileal smooth muscles of the guinea pig. Arzneimittelforschung. 1985;35(1A):408-14.