Cayenne pepper (also known as chili or red hot pepper) is the fruit of Capsicum annuum, a shrub that grows to three feet high. It’s in the Solanaceae family, also called the nightshade family. Related plants in this family include potato, eggplant, and tomato. Native to Mexico and Central America, cayenne is now cultivated in tropical regions throughout the world for food and medicine.
Cayenne is used to add spice and heat to food. The hotness comes from a chemical called capsaicin, which is also one of the botanical’s principle therapeutic substances. Other active constituents include carotenoids, vitamins A and C, and volatile oils. Cayenne has been used historically for asthma and upper respiratory infections and to prevent ulcers.
Eating cayenne pepper may also be helpful for weight maintenance and decreasing insulin resistance (in prediabetes and diabetes). Regular dietary intake of cayenne pepper significantly reduced insulin in a clinical trial. In this study, participants who consumed 30 g per day of chili, composed of 55 percent cayenne pepper, showed lower insulin levels after four weeks, compared to those who did not eat this diet. Clinical trials indicate that metabolism increases while appetite and caloric intake are declines in people who add cayenne to their diets.
In addition, research has been conducted on cayenne pepper for its analgesic effects.
The sensation of pain involves complex interactions among the nervous system and hormonal pathways. One signaling molecule that increases the sensation of pain is called substance P. Capsaicin cream can deplete substance P and reduce pain in such conditions as arthritis, neuralgia (nerve pain), and lower back pain.
Most contemporary clinical research into the pain-relieving effects of cayenne pepper focus on the use of capsaicin creams. Commonly available creams contain 0.025 percent or 0.075 percent capsaicin. The topical use of these creams may provide significant relief of pain in people suffering from many conditions, including diabetic neuropathy, cluster headache, osteoarthritis, and rheumatoid arthritis.
The U.S. Food and Drug Administration (FDA) has approved topical capsaicin cream for the treatment of postherpetic neuralgia (nerve pain caused by a herpes zoster virus outbreak). For example, in one study 39 patients with chronic postherpetic neuralgia (average duration 24 months) used 0.025 percent capsaicin cream for 8 weeks. During therapy the patients rated their pain. Of those treated, more than 40 percent had improved substantially, 13 percent elected to stop the therapy because of side effects (burning sensations), and 38.5 percent received no benefit from this approach. The results of this clinical trial are consistent with other studies.
Some patients diagnosed with trigeminal neuralgia (facial pain in the lips, gums, cheek, or chin) who use capsaicin cream on affected areas report complete or partial relief during flare-ups. These results are promising, since surgery has historically been considered the only effective therapy in many cases.
Women who have undergone mastectomy surgery may experience postsurgical pain. In one study, 19 patients with postmastectomy pain applied 0.025 percent capsaicin cream four times daily for eight weeks. Thirteen of the women reported reduced pain and discomfort. Cream containing 0.075 percent capsaicin has demonstrated similar results in a randomized, placebo-controlled trial.
Research supports the use of capsaicin cream in relieving osteoarthritis and rheumatoid arthritis pain. In one study, 14 patients with osteoarthritis rubbed cream containing 0.075 percent capsaicin four times daily into their hands. Capsaicin cream provided symptomatic relief compared to placebo. In a second study, people with rheumatoid arthritis rubbed 0.025 percent capsaicin cream on painful knees four times daily. Those using the capsaicin cream experienced significantly greater pain relief than those in the placebo group. Individuals with rheumatoid arthritis had a 57 percent mean reduction of their pain.
If you enjoy the heat, add cayenne pepper freely to your diet. Capsaicin creams tend to contain 0.025 percent or 0.075 percent capsaicin, and to work effectively, they should be rubbed into the affected areas up to four times daily.
Toxicity and Interactions
The only adverse effect noted with topical capsaicin creams is local burning, which tends to decrease with time and continued use. However, the pain can be severe enough in a minority of people that they elect to discontinue using capsaicin cream.
Dietary consumption of cayenne pepper is regarded as very safe. But since cayenne is quite hot, this pepper may cause pain and discomfort in people with gastric or peptic ulcers. Some reports have also cited an increase in gastric reflux (gastroesophageal reflux disorder, or GERD) among people consuming cayenne pepper. Consuming cayenne may interfere with MAO inhibitors and some blood-pressure medications, while increasing the rate at which the liver metabolizes other drugs.
John Neustadt, ND, is clinic director of Montana Integrative Medicine (www.montanaim.com) and president and CEO of Nutritional Biochemistry, Incorporated (www.nbihealth.com) and NBI Testing and Consulting Corp (www.nbitesting.com), in Bozeman, Montana.