The Hot History of Chili

By as early as 7500 BC, Mexican Indians have gathered the fruits of Capsicum plants from their surroundings (“Capsicum Peppers”). The fruit (i.e. chili pepper) or fruit extracts were ingested as a food additive but it was also used for medicinal purposes as a topical agent (“Capsicum Peppers”). Asthma, coughs, sore throats and toothaches are some of the conditions that the substance was used to treat (“Capsicum Peppers”). In fact, the plant had become so important for their civilization that between 5200 and 3400 BC, they had succeeded at domesticating certain Capsicum plant varieties to increase supply (“Capsicum Peppers”). 

When these Mexican Indians were discovered by Christopher Columbus in 1493 AD, he acquired samples of Capsicum seeds which he brought back with him to Spain, the emerging centre of spice trade (Govindarajan, 1985). Before long, chili peppers were exported from Spain to different parts of the planet and it eventually became a popular culinary spice in countries such as Thailand, India, Vietnam and Korea (Jing, 2010).

Their history as a food additive is widely popular even today but investigators are beginning to rediscover the efficacy of chili extracts to relieve arthritis pain, chronic back pain, rhinitis, etc. (Derry et al, 2009; Chrubasik et al, 2010; Ciabatti & D’Ascanio, 2009)

Active Component and Preparations

Capsaicin is the chemical responsible for the numerous medicinal applications of chili peppers (“Capsicum Peppers”). Each type of capsaicin-based therapy prepared and administered differently to optimizes capsaicin’s efficacy. In the case of arthritis pains, capsaicin based creams are applied to the sore area for pain relief (“RUBžA535”). Capsaicin has also been used in weight loss pills to increase the body’s metabolic rate in order to burn body fat (Khan, 2010). Nasal sprays with capsaicin also exists for the purpose of relieving sinus and nasal congestion (Sinus Buster, 2010). A recent innovation is the Qutenza transdermal patch which capsaicin as the main active ingredient (Qutenza, 2010). This is used to relieve pain that is specifically due to shingles (Qutenza, 2010).

Medicinal Applications of Capsaicin

Substance P is a neurotransmitter which is secreted by neurons in response to noxicous stimuli or capsaicin (Sicuteri et al, 1990). It binds to the NK receptors of primary sensory neurons which then sends pain signals to the brain (Sicuteri et al, 1990). Repeated application of capsaicin leads to substance P over-secretion and depletion (Sicuteri et al, 1990). NK receptors are left unbound and so the pain is no longer felt (Sicuteri et al, 1990).

With this in mind, the following studies investigated capsaicin’s efficacy to treat soft tissue and chronic back pain and rhinitis.

Study 1:

 

Chrubasik et al (2010) found that Finalgon® which contained capsaicin was effective at improving pain symptoms for chronic soft tissue pain and chronic back pain as seen in the figures. Application of the cream was 3/ day for 3 weeks. 

The only issue with the protocol designed by Chrubasik et al (2010) is that the study was conducted in Germany which may or may not affect the efficacy of the treatment if used for people of different backgrounds. Otherwise, the protocol was sound. The subjects were randomized, the study was double-blind and placebo-controlled. Several outpatient clinics (i.e. 23) were contacted ensuring that results are representative of the actual population in Germany. Strict exclusion criteria were applied to remove patients with psychiatric disorders as well as anything that was expected to reduce compliance (such as drug use). Patients were assured patients that itchiness symptoms were not indicative of efficacy thus maintaining the double-blind nature of the study. Lastly, patients were made to discontinue analgesic medications prior to the study so that the effects of the capsaicin were not confounded with that of the patients’ medications.

Study 2:

Ciabatti & D’Ascanio (2009) have shown capsaicin to be an effective treatment for rhinitis that is of unknown cause (IR). This condition can be induced by substance P secretion by nasal mucosal sensory neurons. Since capsaicin is known to deplete substance P stores, the efficacy of a capsaicin containing nasal spray on IR symptoms was investigated. 

This study showed that a minimum capsaicin dose of 4 micrograms/puff/nostril 3 times each day for three days in a row was required to have a statistically significant improvement in symptoms when compared to placebo.

The study had many strengths which includes but is not limited to strict patient inclusion and exclusion criteria, use of 4 week pre and post treatment observations, and the decision to use different nasal spray doses to see which one would be most effective, if effective at all. The biggest drawback in this experiment was that it was not explicitly described as double blind. Also, results were in the form of pain scores by the patients which are highly subjective. A physiological measurement in addition to the patient scores would have been a more objective means of measuring the efficacy of the treatment.

Conclusion:

Both studies were executed fairly well and so there is provide fairly good evidence that both treatments are efficacious.

Potential Adverse Effects and Drug-Drug Interactions

 In the development of any new medical treatment, adverse reactions must be investigated.

A systematic review by Derry et al (2009) investigated the adverse effects of using capsaicin cream over placebo when treating chronic pain. Local skin reactions such as “burning, stinging, erythema and puritus” were experienced by an average of 63% of capsaicin cream users as opposed to 24% average of placebo users. N. B. these symptoms were mild and transient.

Derry et al (2009) also found that other symptoms such as coughing and sneezing due to dried-cream inhalation were much less common. Symptoms manifested in an average of 9.2% capsaicin cream users as opposed to an average of 1.4% placebo users.

Much more serious adverse effects were rare and not statistically significant from those experienced by placebo users (Derry et al, 2009).

Another study by Babbar et al (2010) determined that capsaicin exposure through ingestion or topical administration is not sufficient to alter functionality of cytochrome P450 (CYP) enzymes which metabolize other pharmaceutical medications used by the patient. This is beneficial because capsaicin treatments can be topically administered with none or minimal drug-drug interaction through CYP enzyme induction or inhibition. 

Ravishing References

Babbar, S., Chanda, S., & Bley, K. (2010). Inhibition and induction of human cytochrome P450 enzymes in vitro by capsaicin. Xenobiotica, 40 (12), 807-816.

Capsicum Peppers. Calantilles. Retrieved Nov 26, 2010, from http://www.calantilles.com/

Chrubasik, S., Weiser, T., & Beime, B. (2010). Effectiveness and safety of topical capsaicin cream in the treatment of chronic soft tissue pain. Phytotherapy Research, 12, 1877-1885.

Ciabatti, P.G., & D’Ascanio, L. (2009). Intranasal Capsicum spray in idiopathic rhinitis : a randomized prospective application regimen trial. Acta Otolaryngol, 129 (4), 367-371.

Cosmetics. Retrieved Nov 27, 2010, from http://www.iso.org/
 
Derry, S., Lloyd, R., Moore, R. A., & McQuay, H. J. (2009). Topical capsaicin for chronic neuropathic pain in adults. Cochrane Database Syst Rev, Oct 7 (4), CD007393.

Eat More Chilies. (2008). Retrieved Nov 28, 2010 from http://www.eatmorechiles.com/

Famous Compounds. Retrieved Nov 27, 2010, from http://www.molecularshirts.com/

Govindarajan, V. S. (1985). Capsicum production, technology, chemistry, and quality. Part 1: History, botany, cultivation, and primary processing. Crit Rev Food Sci Nutr, 22 (2), 109-176.

Hicks. (2009, July 25). What Is Shingles – Symptoms, Treatment and Vaccine Information. Message posted to http://www.clivir.com/

Jing. (2010, July 19). Top 10 Countries That Use Chilies Around the World (Good Paprika Burns Twice...). Message posted to http://foodtrotter.com

Khan, S. (2010, Oct 23). Capsaicin Pills. Message posted to http://www.buzzle.com/

Qutenza. (2010). Neurogesx. Retrieved Nov 27, 2010, from http://www.qutenza.com/

RUBžA535. Arm and Hammer. Retrieved Nov 28, 2010, from http://www.churchdwight.ca/

Sicuteri, F., Fanciullacci M., Nicolodi, M., Geppetti, P., Fusco, B. M., Marabini S., Alessandri, M., & Campagnolo, V. (1990). Substance P theory : a unique focus onthe painful and painless phenomena of cluster headache. Headache, 30 (2), 69-79.

Sinus Buster. (2010). Buster Brands. Retrieved Nov 28, 2010, from http://www.busterbrands.com/

Top Stories- Long-Term Rhinitis Reduces Airflow (2008). American College of Allergy, Asthma & Immunology. Message posted at http://www.news-source.org/

Vidican. (2010). Chili Peppers: Pleasure and Pain. Message posted to http://www.metrolic.com/