Recently, I was invited to do a FB Live program with Leiann as she was conducting a discussion of Fennel Essential Oil. I did a part that dealt with a few items that are not normally found in various write ups and discussions on this particular essential oil. So I would like to convey some of those ideas and add to what was discussed.
Fennel oil can be expressed in two types, one is Sweet Fennel and the other is Bitter Fennel. In aromatherapy we find that Sweet Fennel is the one normally used. The only real difference between the two is the levels of the constituents and their ratios. Many times Bitter Fennel is passed off as Sweet Fennel. In my opinion, for most aromatherapy applications it isn't that big deal, except that it is being misrepresented. The constituent levels and ratios are the main concern for this particular oil. Fennel, whether in the herbal forms or essential oil form, tastes much like black licorice.
Perhaps one of the main concerns with using this oil is the estrogen effects on the person. This oil carries a caution that pregnant women shouldn't use it for that reason. In some propaganda papers on this oil it cautions against the use of Fennel oil on small children. However, in one study of 62 infants that were clinically observed for infantile colic, it showed no ill side effects presented. This was done at the 12mg/kg/day level of dosage for 7 days. It was noted that one week of use isn't likely long enough for any estrogenic effects to show. (Alexandrovich et al 2003), (Essential Oil Safety, 2nd. edition, Tisserand). So even, typically Fennel oil will carry a caution for children. Short term use for colic is beneficial with no side effects when used rationally. Normal use in this situation effects by applying the oil to the nursing mother and then its effects carried through the milk. A side benefit is that it is believed to help with increasing the milk production. I will discuss this in more detail later in this discussion. Further more, Fennel was shown to present premature breast growth in girls between the age of 5 months and 5 years of age, (Bilia et al 2002). This case study was done on 4 girls, so the sample group was very small. They had been drinking Fennel Tea for several months. Upon stopping the tea, the premature thelarche returned to normal levels with the 3-6 month time period. So the lesson learned here is that short term use on children will be, when other things are normal, just fine but prolonged high level use is not the best course to follow for children.
Fennel oil seems to be beneficial for adults and older children. In other studies we see results saying that in some high concentration levels, Fennel oil can be toxic to some fetal cells but does not impact normal development, (Ostad et al 2004). In rodent studies it was shown that Fennel oil had no adverse effect on sperm, and in fact it significantly inhibited sperm abnormalities caused by Cyclophosphamide, a drug class used to treat cancer and autoimmune diseases, (Tripathi et al 2013).
Along those lines, Fennel oil has been shown to demonstrate antioxidant activity, (Ruberto et al 2000). Sweet Fennel oil has been shown to reduce blood glucose levels in diabetic cases, (Essway et al 1995). This is why Fennel is used in some formulations of oils related to use for diabetics. However, there are some safety precautions for SOME antidiabetic and anticogagulant medicines due to the cardiovascular effects. See Tisserand's book, pg. 59. As the list is too complex to explain here so check with you health care provider. Of course if you have any cancers, or other medical conditions that are estrogen dependent or could effect a negative condition, caution is advised.
As a side note, in the studies that I read regarding this oil and it's constituents, there is a theme through out the literature. It works fantastic on the male gender with virtually no negative gender specific issues with every thing being positive. In the female gender, there are a few cautions. In both of these observations it is assumed that the oil is used rationally and in normal aromatherapy use levels. So men, this is your oil! So, now that we have looked at the list of cautions and cited studies to support those ideas, lets move on to some other aspect of this wonderfully effective and useful oil.
As we look at some other other positive effects, we have to look at the messed up conditions in which Fennel could serve as a useful tool in dealing with those conditions. The first one deals with parasites. One parasite that I came across in working with people starting years ago is one called Leishmania. This is a really devastating problem for those affected by it. There are many different versions of this parasite and different presentations of it. Although it is classified as a Protozoa type parasite, it is somewhat like a worm and behaves much like a worm. Worms are generally classified as a Nematode, but more on that later. This condition claims as its victims, people that have spent time in the sandbox, aka, Middle East, serving in war conditions. However, this parasite can be found in most every part of the world and under all conditions. What happens it that the person is bitten by the female sand fly and then the parasite is passed on to the victim. Depending on which version of this is the culprit, the manifestation of the disease can vary. Some times it shows up on the skin, sometimes in the blood or in the digestive tract. The one in the brain is really hard to eradicate and could be responsible for the degenerative mental conditions being manifested in many people on their return home. Working with these affected people can be a challenge. In the ones with the brain affected types it sort of becomes a coping protocol rather than one of fixing the problem. The blood borne, skin types, and digestive types, are easier to work with. However, as with anything like this when working with these body systems, one must follow a detox protocol of some type, as it relates to and is dependent on the type of issue and the individual person involved.
Now as we return to the Nematode category. We find that a Nematode is a worm in simple terms. Most of these "worms" are not our best friend, although some are or could be a good friend to use and are necessary for normal life functions. However, it seems like those that are not our friends can easily be worked with using certain products. We do find a number of these various types of Nematodes in plants. So they are not exclusive to animal life forms. It has been shown that exposure of Fennel Oil, particularly the main chemical constituent found in Fennel Oil, Anethole, is very effective in either killing or stunning the worms, allowing them to pass from the host. Another aspect to this is that Fennel Oil is effective against a long list of weevils, beetles and- drum roll... the good old indestructible cockroach. Can you believe that? Cockroaches have been know to live through a nuclear blast, extreme high radiation levels and carry on as though nothing happened. Only to be done in by Fennel Oil. Normally when working with most of these "bugs" a form of diffusing is indicated, called fumigant or fumigation. Which is essentially the industrial form of diffusing. So either a form of contact (neat) or diffusing is effective against these bugs. When used as an insecticide, against forms other than Nematodes, Fennel Oil (anethole) is effective against a wide cross section ofthe larvae of Mosquito, Gnats, and Mites. So that would explain why it is effective when working with the above listed Leishmaina.
One area that I have mused over with regard to Fennel Oil, is the use of Fennel Oil with milk production in dairy cows. See the reason I mention this is because Fennel has a chemical structure that is similar to Dopamine and thus interacts with the dopamine receptors and disinhibits the receptors to effect and increase Prolactin excretions. This leads to increased milk production. In studies it is believed that Fennel Oil directly leads to increased milk production.The reason why I muse over this is because it wasn't very many years ago that a lot of dairies used a product called rBST to increase milk production in the cows. Of course a hated chemical company related to GMO and chemical production used on food products was the maker of it. It increased the production by about 10% but oh the costs. The cow ate a lot more and the cow only lasted about 3 years before she was totally burned out. She would just kick over, nothing but a rack of skin and bones. With normal and rational care a typical cow can last 10 or more years, even in an industrial milk production setting. I wonder if feeding fennel to the cows would in effect have the same positive milk production effect with out the negative presentations. Just thinking out loud... Since Fennel oil can affect the dopamine receptors, it stands to reason that since dopamine is the feel good-reward mechanism of the central nervous system; one can be lead to see that Fennel oil can have an enormous effect on the emotional state. This is rational thinking because yes, in some studies it has been shown that Fennel can be effective in boosting a person's mood and mental well being.
Overall Fennel oil is one of those oils that works on so many different aspects and on so many different conditions. I have listed a wide range of conditions and given you a lot of perspectives on the what Fennel Oil can be used for or with and on what conditions. The discussion about Fennel Essential Oil can go on for a long time, much longer than we have space and time here for. So we will bring this discussion to a close.