Capsaicin Causes Pain, No Gain

Emily Johnson Capsaicin

William Yang presents “Capsaicin suppresses body weight gain and pain reaction in mice” at the Experimental Biology 2016 meeting in San Diego. Credit: Emily Johnson

Capsaicin is a chemical people love or hate. It’s the chemical in hot peppers and spicy foods responsible for their spicy (and sometimes painful) taste, but researchers in Maryland and Pennsylvania think it may have some health benefits. William Yang, a high school student who worked on the project at the Temple University Lewis Katz School of Medicine in Philadelphia, shared their findings at the Experimental Biology meeting in San Diego.

The research team gave mice capsaicin for a total of 90 days. Mice fed capsaicin gained 16.5 percent less weight than mice in the control group, suggesting that capsaicin either changed their appetite or their body’s metabolism. The mice also showed changes in their ability to handle high blood sugar and high insulin levels, indicating that capsaicin has effects on metabolism.

Yang says future studies are underway in the group’s laboratory to discover how and why these changes happened. In the meantime, the findings tell us that the beneficial effects of eating spicy foods might be worth a little bit of pain.


Emily JohnsonEmily Johnson, PhD, is an APS member and a former volunteer editor for the I Spy Physiology blog.

Your Sweet Memory

Emily Johnson Sugar Learning

Esmeralda Morales-Gonzalez presents her poster “Does chronic sweetener intake affect learning?” at the Experimental Biology 2016 meeting in San Diego. Credit: Emily Johnson

Most of us know it’s not healthy to eat a lot of sugar. Overeating sweets for a long time can cause weight gain, cavities, type 2 diabetes and other health problems. But what if sweets also had effects on your brain and memory? Researchers at the Universidad Autónoma del Estado de México reported at the Experimental Biology 2016 meeting in San Diego that consuming too much sugar may have negative effects on memory.

Esmeralda Morales-González and her colleagues in the neuroscience research group gave mice either water, sucralose (an artificial sugar) in water or sucrose (real sugar) in water for five weeks. They tested how well the mice learned to solve a water maze. For five days, mice were allowed to learn the location of a hidden platform in a mouse swimming pool. (The platform allows mice to stand and rest so they want to find the platform as quickly as possible.) On the sixth day, the research group measured how long it took the mice to get to the platform.

Mice in the sugar group took longer to find the platform, suggesting they had not learned as well as the mice in the other two groups. The fact that sugar impaired learning in mice is still an early finding, and Morales-Gonzalez stresses that more tests need to be done to confirm their data could apply to humans. For now, the data suggest that sugary treats may have not-so-sweet effects on memory.

Emily JohnsonEmily Johnson, PhD, is an APS member and a former volunteer editor for the I Spy Physiology blog.

Chemicals in Plastic May Be Bad News for Mothers and Babies

Emily Johnson Plastic Chemicals

Coral Hahn-Townsend presents “Metabolic dysfunction induced by prenatal exposure to Bisphenol-A and Diethylhexyl Phthalate: exacerbation by a high fat diet” at the Experimental Biology 2016 meeting in San Diego. Credit: Emily Johnson

If you’re a health-conscious shopper, you’ve probably noticed a new generation of “healthier” plastics popping up in grocery stores. These new plastics are “BPA-free,” which means a chemical called bisphenol-A (BPA) has been replaced with alternative chemicals. But are chemicals in plastic really something to be concerned about? Researchers from the University of Georgia and Michigan State University who study this question presented their findings at the Experimental Biology meeting in San Diego.

Coral Hahn-Townsend and other members of the research team studied how BPA and another chemical in plastic, diethylhexyl phthalate (DEHP), affected baby rats who were exposed to these chemicals during their mother’s pregnancy. “BPA is kind of like estrogen, and DEHP is an anti-androgen,” meaning they are endocrine disruptors, Hahn-Townsend explains. A lot of people are exposed to these chemicals in the environment, and it’s possible that they have an effect on our body weight and metabolism, she says.

After exposing the pregnant rats to the chemicals, the researchers studied their litters into adult life. Adult rats exposed to BPA and DEHP as fetuses had higher body weight than unexposed rats. They also showed early signs of diabetes, which worsened when the research team fed them high-fat diets.

Plasticizers—chemicals such as BPA and DEHP used to create plastic containers—are extremely common in both food products and the environment. However, scientists are only starting to understand how these chemicals may affect our bodies. Stay tuned for future research on their effects on present and future generations of humans and animals.

Emily Johnson

Emily Johnson, PhD, is an APS member and a former volunteer editor for the I Spy Physiology blog.

To Play Better, Skip the Post-Game Drink

Emily Johnson EB Post-Game Drink

Study authors Rafael Jimenez and Amy Engel present their poster “Effect of post-exercise ethanol on signaling pathways regulating mitochondrial biogenesis” at the Experimental Biology 2016 meeting in San Diego. Credit: Emily Johnson

Sports and alcohol are a famous pair. Whether you’re a fan or an athlete, it’s common to follow up a great game with a drink or two. But does that drink affect your recovery after your workout? Researchers at California Polytechnic State University think that it might.

Rafael Jimenez, Amy Engel and a team of scientists studied this question by exercising rats for 60–90 minutes, then giving some of them ethanol, which is the type of alcohol found in alcoholic beverages. It was a heavy dose of alcohol, Jimenez says, noting that in other studies the dose produced a blood alcohol content of about 0.27 percent. (That’s equivalent to a 140-lb. man having about 9–10 drinks.) Three hours after the rats’ intoxication, the researchers measured the expression of recovery proteins in the rats’ muscles.

In particular, they measured the expression of PGC-1α, an important gene involved with the cell’s recovery response to exercise. PGC-1α is a major player in the creation of new mitochondria—the “engines” that provide cells with energy.

The expression of PGC-1α in muscle cells increased in all the rats after exercise. However, this increase was blunted in the rats that received ethanol. These findings are preliminary, but they suggest that drinking after exercise impairs recovery by keeping the cells from making more mitochondria. So next time you have a great workout, celebrate with a virgin margarita instead of an alcoholic drink to optimize recovery.

Emily Johnson

Emily Johnson, PhD, is an APS member and a former volunteer editor for the I Spy Physiology blog.

Of Ice Swims and Mountain Marathons (and So Much More)

If you regularly read this blog, you may know that the research questions that physiologists ask relate to wide range of topics—cells, tissues and organs, insects and animals, and how the environment influences all of these things. Nowhere is this more apparent than at the annual Experimental Biology meeting. This year, thousands of physiology-based research abstracts were presented over five days. Read on to learn about two research studies on extreme sports that caught our eye.

Glacier Dive

Credit: Ram Barkai

Ice swimming is growing in popularity, with hundreds of athletes worldwide giving this chilly sport a try. Human performance in water this cold—swims must take place in water that’s 5 degrees Celsius or colder—has not been well-studied. In a study presented at the EB meeting, researchers looked at how age, gender and environmental factors such as wind chill affected athletes during one-mile ice swims. Among other results, they found that age doesn’t have a large effect on swim times, suggesting that athletes can be competitive in the sport well into their 30s and 40s. This is significantly older than the average age of the athletes on the most recent U.S. Winter Olympic team (26 years old), giving hope to older athletes as the sport is being considered as a new Winter Olympics event.

Man Running Uphill

Credit: IStock

Fifty kilometer (~31 mile) mountain ultramarathons test athletes aerobic and anaerobic fitness through changes in elevation, terrain and weather. Aerobic fitness refers to how the body uses energy when there is enough oxygen, such as the energy burn that occurs when running at a comfortable pace. Anaerobic fitness refers to the body’s ability to exercise when there’s not enough oxygen, such as during a sprint to the finish line at the end of a race. While it may seem that aerobic fitness would be a better predictor of how fast a person would finish an ultramarathon, researchers found that competitors with the best anaerobic fitness finished faster. That’s why exercises that build anaerobic endurance, such as uphill sprints, would be a worthwhile addition to the training regimen of anyone preparing for this type of race.

These studies were just the tip of the iceberg. Read more physiology research highlights from the EB meeting:

How exercise to protect the blood vessels from stress

Why a high-salt and high-sugar diet is a fast track to high blood pressure

The benefits of gastric bypass surgery that occur before the weight comes off

Elephant seals that protect themselves with CO2

What tobacco hornworms can tell us about fat metabolism

How an inhaler could protect against life-threatening accumulation of fluid in the lungs

Stacy Brooks