Essential oils are practically synonymous with health in American culture. People say 'essential oil' like they're saying 'broccoli' or 'carrot'...implying both healing properties and an innocuous presence simultaneously. But, have you ever stopped to wonder what is in your essential oils? The answer might surprise you.
For our case study, we're going to take a look at one of the most popular essential oils: peppermint.
First bear with me and check out the chemical details. These are the active constituents per the current PubChem entry and their IUPAC names:
- (5-methyl-2-propan-2-ylcyclohexyl) acetate
(National Center for Biotechnology Information. PubChem Compound Database; CID=6850741, https://pubchem.ncbi.nlm.nih.gov/compound/6850741 (accessed Oct. 10, 2016).)
So, you're wondering why I'm showing you this very boring science stuff?
A couple of reasons, the first being, as I've noted in blogs before, all ingredients are chemicals. This is a point that is often forgotten by people who are not chemists, so it bears repeating. Just because the label says peppermint essential oil it doesn't mean it isn't a chemical. In fact, your product contains the whole suite of chemicals shown above. This is true for other essential oils as well.
The second reason, is to give you a visual of why essential oils have the effects they have. Many have been used medicinally for centuries. It is not magic, there are active ingredients in them! What is an active ingredient? It is any chemical that causes a physiological change. They perform an action on the organism. The term 'active ingredient' is most often seen on medicine packaging, where it is required by law. Nature has active ingredients too though they won't be listed on packages (usually).
So what does it mean that essential oils have active ingredients? It means they are affecting change in your body when you use them. Historically, peppermint has been used to calm digestion, invigorate the senses and as a respiratory aid to clear congestion and calm coughs. If you take peppermint essential oil at a level that it can affect health, it is a medicine and needs to be respected a such!
But, how does it work?
Researchers have found that peppermint relaxes intestinal cells by reducing the uptake of calcium and it does so in a concentration dependent manner, very similarly to the dihydropyridine family of hypertension drugs. (Hills & Aaronson, Gastroenterology, 100 (1), 1991, pp 55-65) If you aren't familiar with muscles, the big picture introduction is that they work by a highly regulated pathway involving calcium causing contraction and magnesium causing relaxation. By preventing the uptake of calcium, the cell is unable to contract and you start to feel better. This relaxing effect is observed in other types of cells as well, including those of the respiratory system making it a popular cure-all during cold season.
And what happens if you take too much?
Ok, it sounds awesome so far, but biological systems can be confounding. It is important to remember that more is not always better just like the glass of wine you drink with dinner that has positive health benefits, but if you drink the whole bottle it is going to do some liver and brain damage.
The good news is peppermint has a low toxicity. The LD50 for rats is 2426 mg/kg consumed orally (Lewis, R.J. Sax's Dangerous Properties of Industrial Materials. 9th ed. Volumes 1-3. New York, NY: Van Nostrand Reinhold, 1996., p. 2600) LD50 is the dose required to kill half of the rats, the LD stands for 'lethal dose'.