July 27, 2015

I've been on a bit of a mint kick lately.

For example, I put a few drops of peppermint essential oil in my daily SodaStream carbonated water that I make to keep my appetite satiated between meals. Occasionally, if I really want to feel like I'm “drinking Christmas”, I'll throw in a few drops of chocolate stevia to make mint-chocolate water. I don't know why this makes me feel like it's Christmas-time, but it just does. So there.

But there are other ways I've been using mint too.

For example, because of research that you're going to learn about a bit later in this article, I've been dabbing a little peppermint essential oil on my upper lip prior to hard workouts, and also when I need a “wake-me-up” boost of focus while working on books, articles, etc.

And then of course, there's my peppermint fat bomb, which also happens to go quite well with chocolate flavored substances. To make this, I blend or vigorously stir 4 ounces of BPA-free full fat coconut milk with a few drops of peppermint essential oil, a tablespoon of alkali-free dark chocolate powder and a few chunks of very dark, dairy-free, gluten-free chocolate. I then throw this in the freezer for about 20-30 minutes and…voila! A healthy and extremely satiating peppermint fat bomb.

You're going to learn why I like peppermint so much in today's article, written by guest author and naturopathic physician Sarah LoBisco, who you may recognize from the podcast episode “Everything You Need To Know About Essential Oils For Fat Loss, Performance, Smart Drugs, Scar Healing, Detoxing And More.”

 

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Peppermint 101

There are over 25 species in the genus “mentha“, some existing as pure species, some existing as hybrid species, but by far the most important, useful and popular being peppermint, which is a cross between water mint (M. aquatica ) and spearmint (M. spicata). The majority of scientifically validated mint studies to date have focused specifically on this peppermint version of herb.

Peppermint (Mentha x piperita) is a perennial herb that grows in moist, temperate areas and blooms from July through August.¹ The plant grows about 2-3 feet tall and sprouts tiny purple flowers. It is native to Europe and Asia, though some varieties are indigenous to South Africa, South America, and Australia. Today, peppermint has been nationalized to much of Europe and North America.

Peppermint is one of the most popularly consumed single ingredients used in herbal teas, which are brewed from the peppermint plant leaves. The leaves contain the phenolic constituents of rosmarinic acid and several flavonoids, including eriocitrin, luteolin and hesperidin. The essential oil of peppermint has been used in traditional medicines³ as well and, commercially, the oil of peppermint is used as a fragrant component in personal care items such as soaps and cosmetics.Peppermint oil consists of many components, including menthol menthone, menthyl acetate, menthofuran 1,8 cineol and pulegone. These compounds act in synergism to give peppermint a wide array of applications,³ and it is even used quite widely as a flavoring agent in pharmaceuticals and the food industry.¹

The therapeutic use of peppermint, however, far surpasses its enticing minty smell and has many impressive benefits, perhaps the most well-known being peppermint's long history of supporting the digestive system.^1-2

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Digestive Health

If you've ever sucked on peppermint when you've had a stomachache, drank peppermint tea for bloating, gas, diarrhea or constipation, or even sniffed peppermint oil or dabbed it on your upper lip to control nausea, morning sickness or motion sickness, then you were on the right track.

Peppermint oil has been proven in several randomized trials to improve symptoms related to irritable bowel syndrome.^4-9 A 2005 literature review of 16 different trials concluded that peppermint oil may be a first choice option “in IBS patients with non-serious constipation or diarrhea to alleviate general symptoms and to improve quality of life.” ⁹

Peppermint oil also has been studied and found to be supportive for other digestive issues such as esophageal spasms, ^10-12 assisting with stomach emptying, ¹³ general digestive discomfort in adults and infants, ^14-15 and feelings of queasiness.^16-17

 A review article in Phytotherapy Research also supported the use of peppermint leaves in tablet or encapsulated form to improve gastrointestinal symptoms as compared to placebo.

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Other Uses for Peppermint & Menthol

In addition to enhancing cognitive focus during your workout, peppermint oil may also help open your lungs or reduce nasal congestion pre-workout (or at any other time you want to breathe better during the day) and has been shown to be helpful in supporting the respiratory system. ^22-23  Rats with nasal symptoms were given peppermint leaves and stems and fractions containing luteoin-7-O-rutinoside, a flavonoid, seemed to suppress sneezing of these rodents.

Peppermint oil has been shown to support the immune system and has been studied for in vitro activity of inhibition of unwanted critters. ^18-21

If you're traveling to an area affected by radiation, such as Japan or sections of the Pacific ocean, you may want to bring along some peppermint. Several animal studies have shown positive results using mint for protection against radiation. ^24-25 In an in vivo study, mice were given either double distilled water or leaf extract of M. piperita orally for three days. Following their final dose, they were exposed to 8 Gy of gamma radiation. Animals pretreated with the leaf extract of peppermint and exposed to 8.0 Gy gamma radiation exhibited a significant increase in the activities of the powerful antioxidant glutathione.

This led the authors to conclude, “The results of the present investigation suggest the antioxidant and free radical scavenging activities of leaf extract of M. piperita are the likely mechanism of radiation protection.”

But the free radical scavenging and antioxidant benefits of peppermint don't stop with protecting you from radiation. An in vitro comparison study to assess the phenolic and antioxidant scavenging power of peppermint preparations evaluated the following: light petroleum (PE), dichloromethane (CH2Cl2), acetonitrile (ACN), ethyl acetate (EtOAc), methanol (MeOH), n-butanol and water (H2O) extracts. The EtOAc, ACN and H2O-soluble peppermint extracts demonstrated the most potent iron(III) reductive and hydroxyl free radical scavenging properties. The PE, MeOH and H2O peppermint extracts demonstrated moderate iron(II) chelating activity.

And here's an FYI for you guys out there: another study on the antioxidant capacity of peppermint is entitled, “Protection against radiation-induced testicular damage in Swiss albino mice by Mentha piperita.” Peppermint also plays a potential role in prostate cell health, with an in vitro trial supporting menthol’s role in modulating prostate cell health via a complex mechanism with the active form of vitamin D. ³⁰

Women: don't feel left out. A 5 day study with 21 women experiencing hirsutism, which is an abnormal growth of hair on a person's face and body, especially on a women with Polycystic Ovarian Syndrome (PCOS), demonstrated positive hormonal benefits after ingesting steeped spearmint tea. The women were assigned to consume the tea twice a day during their follicular phase of their menstrual cycle. The authors reported a significant decrease in free testosterone and increase in luteinizing hormone, follicle-stimulating hormone and estradiol with no significant decreases in total testosterone or dehydroepiandrostenedione sulphate (DHEA-S) levels.

There's a reason peppermint is in your toothpaste or toothpowder too. Peppermint oil may help with dental health, plaque ²⁶ and decreasing dental biofilms.²⁷

Then there's one of my favorite aspects of peppermint for hard-charging folks who need to think better or want to exercise harder: the cognitive support and smart-drug like benefits. A double-blind, placebo-controlled, randomized cross-over design study with 32 healthy subjects found that a “combination of peppermint oil, eucalyptus oil and ethanol increased cognitive performance and had a muscle-relaxing and mentally relaxing effect…” ²⁸

Another study with 44 participants showed benefits of the aroma of peppermint in relationship to memory tests and alertness.²⁹ In a cross-over study with 133 individuals who were assigned to chew mint or fruit gum, researchers noted that:

“Chewing gum was associated with greater alertness and a more positive mood. Reaction times were quicker in the gum condition, and this effect became bigger as the task became more difficult. Chewing gum also improved selective and sustained attention. Heart rate and cortisol levels were higher when chewing which confirms the alerting effect of chewing gum.”  

Note: stay away from aspartame in gum – I know that this B-Fresh Vitamin B-enriched xylitol peppermint gum brand is the stuff Ben Greenfield chews.

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Can Peppermint Oil Damage Your Gut?

American guts are in trouble and athletes especially can be more prone to issues if they aren’t modulating the excessive inflammation and cortisol that can result from strenuous training. This leads many to reach for quick relief such as acid reflux medication and proton pump inhibitors. According to Medscape, Nexium earned $15,298,228 for its stock holders, giving it fourth place for top pharmaceutical sales during April 2014-May 2015. You know that's bad news if you read the BenGreenfieldFitness article “Why Kill Your Stomach Acid”.

Due to all the powers of peppermint, you may be wondering about the safety of using peppermint oil for digestion compared to these dangerous heartburn medications. In this article, I discuss the 3 major factors involved in common sense use of peppermint oil and I take a critical look at toxicity reports. The bottom line is this: essential oils have a very safe track record and the herb peppermint, when used as directed, has very few side effects as well.

However, if you are taking medications such as heartburn medications for digestive distress, there is a potential of their interaction with peppermint oil, due to peppermint’s ability to modulate motility of the digestive tract in vitro and in vivo. Drugs that decrease stomach pH, such as H2 blockers or proton pump inhibitors, could potentially cause enteric coated capsules of peppermint to dissolve earlier (the enteric coating is used in capsules to prevent premature absorption in the stomach).

The Natural Standard Database also reports a potential peppermint interaction with medications that metabolize through a specific liver enzymatic pathway. However, this is also more theoretical evidence and has not been demonstrated in humans. ^36-38

Ultimately, if you're avoiding things like heartburn medications, you don't have anything to worry about when it comes to using peppermint oil for digestion. Hopefully, you’ve been following Ben’s advice about how to naturally heal your gut with diet and supplements and don’t need to worry about this. Rather, you can consider peppermint oil as a potent tool to put in your water in order to enhance your health and support digestive wellness.

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The Exercise-Boosting Power of Peppermint

Peppermint oil has also been studied for its benefits in athletic performance.^31-33 One recent study showed an immediate effect of peppermint oil on athletic performance.

The study included 30 healthy male university students randomly divided into an experimental group of oral administration of peppermint oil (50 ul) and a control group. The study aimed to determine if ingestion of peppermint oil modulated physiological parameters and exercise performance after 5 minutes and 1 hour. The authors measured maximum isometric grip force, vertical and long jumps, spirometric parameters, visual and audio reaction times, blood pressure, heart rate, and breathe rate. The results revealed significant improvement in all of the variables following peppermint essential oil consumption. Specifically, the authors reported:

“Experimental group compared with control group showed an incremental and a significant increase in the grip force (36.1%), standing vertical jump (7.0%), and standing long jump (6.4%). Data obtained from the experimental group after five minutes exhibited a significant increase in the forced vital capacity in first second (FVC₁)(35.1%), peak inspiratory flow rate (PIF) (66.4%), and peak expiratory flow rate (PEF) (65.1%), whereas after one hour, only PIF shown a significant increase as compare with the baseline and control group. At both times, visual and audio reaction times were significantly decreased. Physiological parameters were also significantly improved after five minutes. A considerable enhancement in the grip force, spirometry, and other parameters were the important findings of this study.”

The researchers explained that the improvements in the spirometric measurements (FVC₁, PEF, and PIF) could relate to the effects of peppermint on bronchial smooth muscle.³¹

Another study examined the response of 12 male students after 10 days of supplementation with peppermint oil (.05ml) in water. The trial supported the effectiveness of peppermint essential oil on the exercise performance, gas analysis, spirometry parameters, blood pressure, and respiratory rate in the young male students. The authors also concluded that, “Relaxation of bronchial smooth muscles, increase in the ventilation and brain oxygen concentration, and decrease in the blood lactate level are the most plausible explanations.” (1 ounce is 2 TBSP or 30 ml) ³²

Finally, a third study in 2001 demonstrated that the impact of peppermint odor during exercise in 40 adults improved running speed, hand-grip strength, and number of push-ups verses the non-odor exposed control subjects.³³

In another interesting study, menthol’s cooling effect was assessed by evaluating cycling performance in 12 males in a tropical climate. The athletes “drank 190 mL of either aromatized (i.e., with 0.5 mL of menthol (5 gr/L)) or a non-aromatized beverage (neutral temperature: 23°C±0.1°C, cold: 3°C±0.1°C, or ice-slush: 1°C±0.7°C)…” They concluded, “Cold water or ice-slush with menthol aroma seems to be the most effective beverage for endurance exercise in a tropical climate.” ³⁴

Some people ask me for the references behind using peppermint to cool one down when the body is too hot. There is actually some basic science behind this. Specifically, one major active constituent of peppermint is menthol, and menthol directly effects your thermoreceptors via something called “TRPM8”. Think “icy hot!”

Check out the full menthol section of this study if you want to geek out and explore the fascinating world of thermoreceptors. This may explain why some people report a relief in discomfort with peppermint oil application, via the “gate-control theory.” ³⁵

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Summary (a final word from Ben)

I'm grateful that Dr. Lobisco helped me dig into the peppermint research that you've discovered above, because mint really is one of my favorite natural compounds that I use every day.

But I don't overdo peppermint.

I simply use it a few times per day in water, in gum, in my mint-fat bomb, or on my upper lip, but I'm not constantly chomping on peppermint gum, the mint-fat bomb isn't a nightly ritual and it's only one bottle of peppermint water that I drink each day. Just like anything (and as referenced in this recent fascinating peppermint/athletic performance video at the NutritionFacts website), you can have too much of a good thing. Frankly, in the case of peppermint, too much of it can lower drive.

So yeah, don't smear peppermint all over your body on date night.

But if you do want to use peppermint, I'd recommend these thre sources:

–Peppermint essential oil

–B-Fresh Vitamin B-enriched xylitol peppermint gum

–Organic heirloom peppermint seeds for your garden (mint is extremely easy to grow)

And that's it! Leave your questions, comments and feedback below, and either Dr. Lobisco or I will reply. Happy mint-sniffing.

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References:

1. Natural Standard Database. Peppermint Oil. (Professional Database-Subscription Required).
2. Peppermint
3. McKay, D. L. and Blumberg, J. B. A review of the bioactivity and potential health benefits of peppermint tea (Mentha piperita L.). Phytother.Res 2006;20(8):619-633.
4. M S Alam, P K Roy, A R Miah, S H Mollick, M R Khan, M C Mahmud, S Khatun. Efficacy of Peppermint Oil in Diarrhea Predominant IBS – A Double Blind Randomized Placebo – Controlled Study. Mymensingh Med J. 2013 Jan ;22(1):27-30. PMID: 23416804
5. Cappello, M Spezzaferro, L Grossi, L Manzoli, L Marzio. Peppermint oil (Mintoil) in the treatment of irritable bowel syndrome: a prospective double blind placebo-controlled randomized trial. Dig Liver Dis. 2007 Jun;39(6):530-6. Epub 2007 Apr 8. PMID: 17420159
6. H G Grigoleit, P Grigoleit. Peppermint oil in irritable bowel syndrome. Phytomedicine. 2005 Aug;12(8):601-6. PMID: 16121521
7. R M Kline, J J Kline, Di Palma J, G J Barbero. Enteric-coated, pH-dependent peppermint oil capsules for the treatment of irritable bowel syndrome in children. J Pediatr. 2001 Jan;138(1):125-8. PMID: 11148527
8. H Liu, G H Chen, H Z Yeh, C K Huang, S K Poon. Enteric-coated peppermint-oil capsules in the treatment of irritable bowel syndrome: a prospective, randomized trial. J Gastroenterol. 1997 Dec;32(6):765-8. PMID: 9430014
9. Mayo Clinic. Irritable Bowel Syndrome (IBS) Health Center. Irritable Bowel Syndrome. http://www.webmd.com/ibs/features/irritable_bowel_syndrome?page=2
10. Pimentel M1, Bonorris GG, Chow EJ, Lin HC. Peppermint oil improves the manometric findings in diffuse esophageal spasm. J Clin Gastroenterol. 2001 Jul;33(1):27-31. PMID:11418786
11. M J Sparks, P O’Sullivan, A A Herrington, S K Morcos. Does peppermint oil relieve spasm during barium enema? Br J Radiol. 1995 Aug;68(812):841-3. PMID: 7551780
12. T Asao, H Kuwano, M Ide, I Hirayama, J-I Nakamura, K-I Fujita, R Horiuti. Spasmolytic effect of peppermint oil in barium during double-contrast barium enema compared with Buscopan. Clin Radiol. 2003 Apr;58(4):301-5. PMID: 12662951
13. Masahiko Inamori, Tomoyuki Akiyama, Keiko Akimoto, Koji Fujita, Hirokazu Takahashi, Masato Yoneda, Yasunobu Abe, Kensuke Kubota, Satoru Saito, Norio Ueno, Atsushi Nakajima. Early effects of peppermint oil on gastric emptying: a crossover study using a continuous real-time 13C breath test (BreathID system). J Gastroenterol. 2007 Jul;42(7):539-42. Epub 2007 Jul 25. PMID: 17653649
14. B May, S Köhler, B Schneider. Efficacy and tolerability of a fixed combination of peppermint oil and caraway oil in patients suffering from functional dyspepsia. Aliment Pharmacol Ther. 2000 Dec;14(12):1671-7. PMID: 11121917
15. João Guilherme Bezerra Alves, Rita de Cássia Coelho Moraes de Brito, Telma Samila Cavalcanti. Effectiveness of Mentha piperita in the Treatment of Infantile Colic: A Crossover Study. Evid Based Complement Alternat Med. 2012 ;2012:981352. Epub 2012 Jul 12. PMID: 22844342
16. Anderson, L., Gross, J. (2004). Aromatherapy with peppermint, isopropyl alcohol, or placebo is equally effective in relieving postoperative nausea. Journal of Peri-Anesthesia Nursing, 19, (1), 29-35.
17. Z Tayarani-Najaran, E Talasaz-Firoozi, R Nasiri, N Jalali, Mk Hassanzadeh. Antiemetic activity of volatile oil from Mentha spicata and Mentha× piperita in chemotherapy-induced nausea and vomiting. Ecancermedicalscience. 2013 ;7:290. Epub 2013 Jan 31. PMID: 23390455
18. Silke Nolkemper, Jürgen Reichling, Florian C Stintzing, Reinhold Carle, Paul Schnitzler. Antiviral effect of aqueous extracts from species of the Lamiaceae family against Herpes simplex virus type 1 and type 2 in vitro. Planta Med. 2006 Dec;72(15):1378-82. Epub 2006 Nov 7. PMID: 17091431
19. A Schuhmacher, J Reichling, P Schnitzler. Virucidal effect of peppermint oil on the enveloped viruses herpes simplex virus type 1 and type 2 in vitro. Phytomedicine. 2003;10(6-7):504-10. PMID: 13678235
20. Liang, R. et al. Physical and Antimicrobial Properties of Peppermint Oil Nanoemulsion. J. Agric. Food Chem., 2012, 60 (30), pp 7548–7555. DOI: 10.1021/jf301129k
21. Peppermint, cinnamon bark and lavender essential oils may be useful as antibiotic resistance modifying agents. Phytomedicine. 2013. http://www.ncbi.nlm.nih.gov/pubmed/23537749
22. T Inoue, Y Sugimoto, H Masuda, C Kamei. Effects of peppermint (Mentha piperita L.) extracts on experimental allergic rhinitis in rats. Biol Pharm Bull. 2001 Jan;24(1):92-5. PMID: 11201253
23. V A Shkurupi?, O A Odintsova, N V Kazarinova, K G Tkrachenko. [Use of essential oil of peppermint (Mentha piperita) in the complex treatment of patients with infiltrative pulmonary tuberculosis]. Virol J. 2009 Jan 20;6:8. PMID: 17128800
24. Hanaa A Hassan, Hani S Hafez, Mona S Goda. Mentha piperita as a pivotal neuro-protective agent against gamma irradiation induced DNA fragmentation and apoptosis : Mentha extract as a neuroprotective against gamma irradiation. Cytotechnology. 2013 Jan ;65(1):145-56. Epub 2012 Sep 21. PMID: 23011739
25. Ravindra M Samarth, Meenakshi Samarth. Protection against radiation-induced testicular damage in Swiss albino mice by Mentha piperita (Linn.). Basic Clin Pharmacol Toxicol. 2009 Apr;104(4):329-34. PMID: 19320637
26. Shojaedin Shayegh, Iraj Rasooli, Massoud Taghizadeh, Shakiba Darvish Alipoor Astaneh. Phytotherapeutic inhibition of supragingival dental plaque. Nat Prod Res. 2008 Mar 20;22(5):428-39. PMID: 18404563
27. Iraj Rasooli, Shojaedin Shayegh, Massoud Taghizadeh, Shakiba Darvish Alipoor Astaneh. Phytotherapeutic prevention of dental biofilm formation. Phytother Res. 2008 Sep;22(9):1162-7. PMID: 18729251
28. Göbel H, Schmidt G, Soyka D. Effect of peppermint and eucalyptus oil preparations on neurophysiological and experimental algesimetric headache parameters. Cephalalgia. 1994 Jun;14(3):228-34; discussion 182.
29. Mark Moss, Steven Hewitt, Lucy Moss, Keith Wesnes. Modulation of cognitive performance and mood by aromas of peppermint and ylang-ylang. Nutr Cancer. 2006;55(1):53-62. PMID: 18041606
30. Eun-Jung Park, Su-Hwa Kim, Byung-Joo Kim, Sung-Young Kim, Insuk So, Ju-Hong Jeon. Menthol Enhances an Antiproliferative Activity of 1alpha,25-Dihydroxyvitamin D(3) in LNCaP Cells. J Clin Biochem Nutr. 2009 Mar;44(2):125-30. Epub 2009 Feb 28. PMID: 19308266
31. Meamarbashi A. Instant effects of peppermint essential oil on the physiological parameters and exercise performance. Avicenna Journal of Phytomedicine. 2014;4(1):72-78.
32. Meamarbashi A, Rajabi A. Journal of the International Society of Sports Nutrition 2013, 10:15  doi:10.1186/1550-2783-10-15
33. B Raudenbush, N Corley, W Eppich. Journal of Sport & Exercise Psychology. 2001. 23: 156-160.
34. Riera F, Trong TT, Sinnapah S, Hue O. Physical and Perceptual Cooling with Beverages to Increase Cycle Performance in a Tropical Climate. Hayashi N, ed. PLoS ONE. 2014;9(8):e103718. doi:10.1371/journal.pone.0103718.
35. Simon J Davies, Louise M Harding, Andrew P Baranowski. A novel treatment of postherpetic neuralgia using peppermint oil. Clin J Pain. 2002 May-Jun;18(3):200-2 PMID: 12048423
36. Dresser GK1, Wacher V, Wong S, Wong HT, Bailey DG. Evaluation of peppermint oil and ascorbyl palmitate as inhibitors of cytochrome P4503A4 activity in vitro and in vivo. Clin Pharmacol Ther. 2002 Sep;72(3):247-55.
37. Natural Standard Database. Peppermint Oil. (Professional Database-Subscription Required).
38. Goerg KJ, Spilker TH. Effect of peppermint oil and caraway oil on gastrointestinal motility in healthy volunteers: a pharmacodynamic study using simultaneous determination of gastric and gall-bladder emptying and orocaecal transit time. Aliment Pharmacol Ther. 2003; 17: 445–451.