Capsaicin: Could the compound that gives chili peppers their heat treat diabetes and obesity?

Last month, hot pepper expert Ed Currie received an acknowledgement that warmed his heart. His newly bred pepper, which he dubbed “Pepper X,” had been publicly named the hottest pepper in the world by the Guinness Book of World Records. Pepper X took the infamous title from the Carolina Reaper, another of Currie’s devilish creations.

The engine of Pepper X’s heat is capsaicin, the compound that grants peppers their pungent burn. Pepper X is crammed so full of the chemical that it inflicts immediate, mind-numbing pain upon anyone who merely nibbles it — though some masochists for spice find the experience oddly enjoyable, at least in hindsight.

Currie is one of those masochists.

“I was feeling the heat for three-and-a-half hours. Then the cramps came,” Currie told the Associated Press. “Those cramps are horrible. I was laid out flat on a marble wall for approximately an hour in the rain, groaning in pain.”

But Currie doesn’t only create unbearably hot peppers for the pain, he also shares them with medical scientists researching capsaicin’s potential to cure disease and help people who suffer chronic pain.

From masochistic to medicinal

Capsaicin is already used in skin creams and patches to help relieve nerve pain. When used topically, it initially causes a brief burning sensation once absorbed, but then it desensitizes the nerves in the region where it is applied, causing an analgesic effect that lasts for a few hours.

Scientists are now looking to widen capsaicin’s medical reach. As a team of Brazilian researchers recently summarized in a literature review published in the journal Nutrients, lots of early studies show capsaicin’s potential to aid in the control of obesity and diabetes.

In the body, capsaicin acts on TRPV1 receptors. These are most prominently found in peripheral neurons, and when activated, create the sensation of scalding heat and pain. But TRPV1 receptors are also found in fat tissue, the immune system, and liver cells. Activating them with capsaicin reduces body fat, blood pressure, blood glucose, and cholesterol levels in rodents. Research also has shown that capsaicin subtly increases the production of body heat and reduces inflammation. Even more preliminary studies conducted in vitro find that capsaicin slows down the growth of white fat while transforming it into brown fat. White fat is the more common, energy storing-form of fat while brown fat breaks down blood sugar and fat molecules to create heat.

A capsaicin cure?

In summary, a plethora of preliminary yet promising research finds that capsaicin triggers beneficial effects inside the body, especially in regard to metabolism. But what does research in humans say? Observational studies generally find that people who eat more spicy food, and thus more capsaicin, are no more healthy than people who eat less spicy food. However, there are generally too many confounding variables in these studies to make any clear conclusions.

What about randomized controlled trials? Here, dosing is a problem. The beneficial amount for rodents is equivalent to about six times what the average Korean consumes in a day, and Koreans are known for being fans of spicy food. Is that level of discomfort really worth the potential benefits?

That’s why some scientists are now exploring sibling chemicals to capsaicin called capsinoids. Some of these activate TRPV1 receptors in the broader body but not in the oral cavity. However, it’s not clear if they will have the same positive effects as their pungent sibling.

Capsaicin is generally safe, with few side effects beyond its trademark pain, so you can feel free to experiment yourself. Nausea, cramps, numbness, and confusion can accompany higher doses, but these are often fleeting. Unless you eat a Pepper X, of course.