Spicy foods may heighten our perception of salt

By American Heart Association News

Adding some spice to food may make you more aware of the taste of salt, a new study suggests.

The findings, published in the journal “Hypertension,” indicate that eating spicy foods may help us consume less salt and, ultimately, lower blood pressure.

According to the World Health Organization, people are eating too much salt across the globe, increasing the prevalence of high blood pressure, heart disease and stroke.

That problem prompted Zhiming Zhu, M.D., a professor of cardiovascular medicine and metabolism at the Chongqing Institute of Hypertension in China, to study alternative ways to reduce salt intake.

He and his colleagues decided to specifically focus on spicy food.

Spicy food has been associated with a healthy heart in the past, Zhu explains. People who consume spicy food almost every day have a 14 percent lower risk of death than those who eat spicy foods less than once a week, a 2015 study shows. Those same people are also less likely to die from diabetes, cancer and ischemic heart disease.

In the study, the team first examined if people who eat and enjoy spicy foods actually have lower blood pressure than those who don’t. Participants’ salty and spicy preferences were gauged with taste tests of solutions that contained varying levels of salt and capsaicin, the compound that makes chili peppers hot. Participants also completed a detailed diet questionnaire about their salty and spicy food habits.

The researchers found that those who enjoyed spicy solutions had lower overall blood pressure. These same people were also more sensitive to the taste of salt.

Participants who enjoyed high-salt solutions, on the other hand, had higher blood pressure overall and tended to dislike spicy solutions.

The team then looked at how the brain reacted to salt and capsaicin. Using PET and CT scans, the researchers recorded activity in the brain after participants ingested different concentrations of salty solutions with and without added capsaicin. Activity was specifically analyzed in the insula and orbitofrontal cortex regions of the brain.

“Previous brain functioning studies in humans and animals indicate that the response, or activity, in the insula is correlated with the intensity of taste an individual perceives,” Zhu explained. “The orbitofrontal cortex is often called the secondary taste cortex; its responses, or activity, are correlated with the pleasantness of taste for an individual.”

The scans showed that higher salt concentrations resulted in higher brain activity in both regions of the brain. However, when capsaicin was added to a lower salt solution, brain activity increased and reflected activity that was seen with higher salt concentrations.

“These results indicate that spicy flavor can modify our perception of salt intensity,” Zhu said. “We speculate that just by adding spices to low-salt foods, we may increase our salt taste and perceive the same saltiness as high-salt foods.”

How capsaicin tricks the brain into thinking there’s more salt is not yet understood. Zhu thinks capsaicin may be activating sodium taste receptors on the tongue, thus increasing the intensity of salty taste signaling that goes to the brain.

Does this mean we should be eating more spicy foods to try to lower blood pressure?

Not exactly, said Cheryl Laffer, M.D., Ph.D., of the Comprehensive Hypertension Center at Vanderbilt University School of Medicine.

“My gut reaction is that while this is potentially useful information, it’s not going to change what I do in practice,” Laffer said. “This is just an association study; the researchers are saying that people who eat spicy food have lower blood pressures, but they have no proof that spicy food actually lowers pressure.”

She added, “But what I do tell my patients is that I am pretty sure that lowering their salt intake will lower their blood pressure.”

Until there’s more proof, both Laffer and Zhu agree that incorporating chili peppers into daily cooking couldn’t hurt.