Herbal Tea: Healthier Hot or Cold?

herbal tea

Credit: iStock

Tea—the most widely consumed beverage in the world next to water—can be found in almost 80 percent of U.S. households. In 2017, people in the U.S. consumed over 84 billion servings of tea—that’s more than 3.8 billion gallons! Tea is versatile: served hot or iced, anytime, anywhere and for any occasion.

Herbal tea is gaining popularity among consumers. It is made by boiling herbs or dissolved plant compounds in water to extract the active herbal ingredients. Herbal tea infusions are believed to fight off heart attacks, cancer and other diseases. However, whether it’s healthier to drink herbal tea hot or cold is unclear.

Claire Maufrais, PhD, and colleagues from the University of Fribourg in Switzerland studied volunteers who drank unsweetened, caffeinated herbal tea (yerba mate) either cold or hot. Yerba mate is a plant native to the South American rainforests. Some research suggests that yerba mate may improve blood sugar and cholesterol levels. It is also sometimes used as a natural remedy for chronic fatigue, headaches and depression.

The researchers monitored the volunteers’ heart rate, blood flow, blood pressure, amount of oxygen their bodies used, and how much fat was broken down to release energy (fat oxidation) for 90 minutes after each drink was consumed. They found that drinking the tea at cold temperatures boosted a metabolic process in which the body burns calories to produce heat. Compared to hot tea, cold tea also increased fat oxidation without causing stress to the volunteers’ cardiovascular systems. Maufrais’ next goal is to evaluate if cold herbal tea could be effective for weight control.

Read the full study about herbal tea by the University of Fribourg’s research team in Frontiers in Physiology.

Nathalie Fuentes OrtizNathalie Fuentes is a PhD candidate in the biomedical sciences program at Penn State College of Medicine. Her studies in Dr. Patricia Silveyra’s lab include the development of sex-specific therapies to treat lung diseases, sex differences in asthma-related lung inflammation triggered by ground-level ozone and the role of male and female sex hormones in lung disease. Nathalie is originally from Caguas, Puerto Rico.

Nathalie served as a meeting blogger for Experimental Biology 2018.

Do Caffeine and Menstrual Cycles Affect Athletic Performance?

Rutherford IMG_4772 (1)

Mara Rutherford presents her poster, “Effects of Caffeine and Menstrual Phase on Performance of Female Athletes during Heat Stress,” at Experimental Biology 2018. Credit: Nathalie Fuentes

Menstruation and its effect on athletic performance is not often discussed in athletics, even though most female athletes deal with it in their daily lives. However, more researchers have begun to look at this subject, and some are observing how other factors, such as caffeine consumption, could influence a female’s performance during sports.

A recent survey found that 61 percent of women are self-proclaimed coffee addicts. Previous research has shown that that caffeine stimulates the central nervous system to enhance endurance performance. In addition, many female athletes use birth control pills (oral contraceptives) to regulate their menstrual cycle; these pills may also enhance the effects of caffeine.

Maura M. Rutherford, a student in the department of human kinetics at Saint Francis Xavier University in Canada, and other scientists studied the potential impact of caffeine and hormonal changes across the menstrual cycle on women’s athletic performance. Six recreationally active women who were taking oral contraceptives volunteered for this study. They took a caffeine supplement and then ran 5 kilometers (3.1 miles) at different stages of their menstrual cycle. The investigators found that caffeine supplementation improved the athletes’ performance in the early follicular phase, when the follicles that will eventually release an egg during ovulation start to develop. However, caffeine did not improve the running time in the mid-follicular phase (i.e., ovulation) of the menstrual cycle. These results could be due to a sudden increase in fatigue that was observed in this phase.

Nathalie Fuentes OrtizNathalie Fuentes is a PhD candidate in the biomedical sciences program at Penn State College of Medicine. Her studies in Dr. Patricia Silveyra’s lab include the development of sex-specific therapies to treat lung diseases, sex differences in asthma-related lung inflammation triggered by ground-level ozone and the role of male and female sex hormones in lung disease. Nathalie is originally from Caguas, Puerto Rico.

Nathalie served as a meeting blogger for Experimental Biology 2018.

Can Altitude Affect Blood Flow and Your DNA?

An estimated 400 million people—myself included—live at elevations higher than 1,500 meters above sea level. The beautiful scenery, rugged mountains and clean air are part of the appeal to many of us. But interesting changes in the body seem to occur as a response to living at high altitude. Scientists from all over the world are working hard to understand these changes and how and why they happen.

At increasing altitudes, air pressure in the atmosphere (atmospheric pressure) decreases. Atmospheric pressure helps us get air into our lungs and blood. As the air pressure decreases, we inhale less oxygen with each breath, throwing off our normal breathing patterns,which means we don’t get enough oxygen to use for energy. As a result, the blood flow to the brain increases. This is called hypoxia. Carbon dioxide in the blood also decreases (hypocapnia), which causes decreased blood flow in the brain. Two researchers presented posters at the Experimental Biology 2018 meeting in San Diego that explore the role of genetics, cerebral blood flow and altitude on our bodies.

Lafave IMG_4773

Hailey Lafave presents her poster, “Tracking cerebral blood flow regulation during incremental ascent to altitude: Effect of superimposed hypoxia and hypocapnia” at Experimental Biology 2018. Credit: Nathalie Fuentes

Hailey C. Lafave, of Mount Royal University in Alberta, Canada, studied hikers who trekked 4,370 meters above sea level over seven days in the Nepal Himalayas. The hikers’ vital signs were measured at 1,400 meters on day 1; 3,440 meters on day 3; and 4,370 meters on day 7. The study found that the hikers’ blood oxygen levels and blood pressure decreased at higher altitudes. Blood flow increased on the seventh day of hiking (at an elevation of 4,370 meters), but not at lower elevations (3,440 meters) on the third day. This novel finding could be used as a metric to detect hypocapnia on cerebral blood flow regulation at altitude.

Lawrence IMG_4770

Elijah Lawrence’s poster, “Genetic missense variants at the EGLN1 locus associated with high-altitude adaptation in Tibetans are rare in Andeans” at Experimental Biology 2018. Credit: Nathalie Fuentes

Elijah S. Lawrence, of the University of California, San Diego, collaborated with researchers at the Universidad Peruana Cayetano Heredia in Peru to study why people who live at high altitude full-time experience hypoxia. The results demonstrate one of the most rapid evolution observations in humans. Lawrence found differences in the DNA of people living in high versus low altitudes. Genetic variations associated with hypoxia may be why some populations living at high altitude are particularly adapted to their environment and suffer from less severe hypoxia-induced complications.

As we continue to learn how hypoxia and hypocapnia affect the body and how we genetically adapt to our environment, remember to breathe slowly and deeply when you’re at high altitude to decrease your heart rate. This will help your body take in the oxygen it needs.

Nathalie Fuentes OrtizNathalie Fuentes is a PhD candidate in the biomedical sciences program at Penn State College of Medicine. Her studies in Dr. Patricia Silveyra’s lab include the development of sex-specific therapies to treat lung diseases, sex differences in asthma-related lung inflammation triggered by ground-level ozone and the role of male and female sex hormones in lung disease. Nathalie is originally from Caguas, Puerto Rico.

Nathalie served as a meeting blogger for Experimental Biology 2018.

How, What and When to Eat: Scientists Weigh In at Experimental Biology 2018

Each year, scientists who study physiology and other biomedical research fields—including anatomy, biochemistry, pathology and pharmacology—gather at the Experimental Biology (EB) meeting. Scientific meetings such as EB provide a platform to present and learn about new and cutting-edge research and form collaborations with colleagues that can lead to advances in science and medicine. This year’s EB meeting in San Diego featured studies ranging in topics from nutrition and exercise to mental well-being and women’s health. Read on for more about how the food we eat—and when we eat it—affects the body.

glasses of milk

Credit: iStock

You may already know that probiotics—live bacteria found in yogurt and nutritional supplements—are good for digestive health. Now researchers from Auburn University in Alabama have found that drinking kefir, a fermented milk-based beverage, may help lower blood pressure. Their study suggests that probiotic-rich kefir restores balance to bacteria in the intestines and an enzyme in the brain that controls nervous system function. It seems the gut and brain are working together to regulate blood pressure.

Diner: Artificial Sweetener Caddy

Credit: iStock

Have you replaced the sugar in your morning coffee with a no-calorie artificial sweetener? This approach may help you cut calories, but according to researchers from the Medical College of Wisconsin, it may not reduce your risk of obesity or diabetes. Their data suggest that zero-calorie sweeteners change how the body processes fat and gets energy. Moderation with any type of sweetener, artificial or natural, seems to be the key.

eating breakfast

Credit: iStock

Breakfast skippers: New research from the Mayo Clinic suggests that passing on breakfast may be a cause of weight gain. Adult volunteers were found to gain less weight when they ate breakfast at least five days a week when compared to those who broke their fast later in the day. The results appear to confirm what your mother always told you: “Breakfast is the most important meal of the day.”

If you’re considering becoming pregnant, make sure your prenatal multivitamin includes zinc. Researchers at Pennsylvania State University found zinc is crucial for the health of a woman’s eggs. Zinc deficiency seemed to impair the development of eggs very early on, months before they are ready for release (ovulation) and fertilization. Zinc-deficient eggs were smaller and had problems with cell division, which can prevent fertilization from occurring.

Alternate-day fasting is a weight loss method that’s recently become more popular—but does it work? A research team from Kent State University in Ohio found that obesity-prone mice lost more weight when their calories were restricted every other day than lean mice did. This was the case even though the mice burned the same amount of calories on fasting and non-fasting days. The results suggest that alternate-day fasting may be effective in some people, but not as much in others.

Interested in learning about more research presented at the meeting? Read Meditation, Stress and Mental Fatigue: Research from Experimental Biology 2018.

Erica Roth 

Meditation, Stress and Mental Fatigue: Research from Experimental Biology 2018

Each year, scientists who study physiology and other biomedical research fields—including anatomy, biochemistry, pathology and pharmacology—gather at the Experimental Biology (EB) meeting. Scientific meetings such as EB provide a platform to present and learn about new and cutting-edge research and form collaborations with colleagues that can lead to advances in science and medicine. This year’s EB meeting in San Diego featured studies ranging in topics from nutrition and exercise to mental well-being and women’s health. Read on to learn more about the relationship between mind and body.

Close up shot of runner's shoes

Credit: iStock

When you’re physically tired, you may feel like your entire body slows down. You might have trouble keeping your eyes open or putting one foot in front of the other. However, science says something different: In older adults, it’s mental fatigue, not physical energy, that affects walking ability. Researchers from Clarkson University in Potsdam, N.Y. asked a group of seniors to perform a timed walking test that tired them out physically and then gave them math problems to sap their mental energy. They found that the more mentally—not physically—tired the volunteers were, the more their walking speed and stride length decreased.

Meditating at the Office

Credit: iStock

Mindfulness meditation can help calm your mind and body. As it turns out, the practice of focusing on your breathing and thoughts may reduce your risk of heart disease after one 60-minute session. Researchers from Michigan Technological University tested the blood pressure, heart rate and artery stiffness of people with anxiety after an hour-long meditation class. All of these factors improved after a single meditation session. That’s reason enough to get your Zen on.

Woman alone and depressed sitting at the beach

Credit: iStock

“Summertime and the livin’ is easy”… or so you thought. However, a study from Poznan University of Medical Sciences in Poland finds that for some medical students, stress hormones rise in the summer when compared to the colder, darker winter season.

Interested in learning about more research presented at the meeting? Check out these studies focused on women’s health and exercise:

Black moms may burn calories slower than white moms to keep more baby weight

Zinc deficiency before conception may make it harder to conceive

Regular soaks in a hot tub may improve insulin resistance and reduce inflammation in obese women

Drinking water may help exercising seniors stay mentally sharp

Exercising after concussion may help teens recover

Erica Roth

Hypertension: Silent and Unequal

Nurse checking blood pressure for mature African American man

Credit: iStock

High blood pressure has been coined the “silent killer” because it has no symptoms, which causes many people to go undiagnosed. A blood pressure reading that stays high for long periods of time is called hypertension. It’s one of the leading risk factors for heart disease.

In addition to being silent, hypertension is also unequal—rates in black people are much higher than in any other racial group in the U.S. An estimated 46 percent of black adults in the U.S. have hypertension. But because guidelines for diagnosis changed recently, this number is likely to be underestimated.

The physiological reasons behind this racial discrepancy are unclear. Some studies suggest differences in the response to stress. One study showed that young black men had greater nervous system responses than white men when faced with a physically stressful situation—in this case, plunging their hand into an ice water bath.

The researchers looked at activity (called sympathetic activity) in a part of the nervous system that regulates heart rate, force of heart contractions and can decrease the size (constriction) of the blood vessels. Constriction of blood vessels during exercise is good, as it redirects blood and oxygen to the muscles. However, too much sympathetic activity can result in unneeded blood vessel constriction and an increase in heart rate that significantly raises blood pressure. The black participants’ surge in sympathetic activity in the ice water test was accompanied by large spikes in blood pressure, which has been linked to future development of hypertension.

A more recent study suggests that the racial disparity may also lie in the blood vessels’ response to nervous system activity during periods of rest. The researchers inserted a tiny probe into a nerve of the leg to measure sympathetic activity in the muscles. They also looked at blood flow in the artery of the leg and blood pressure throughout the resting period. They found that black men had greater vessel constriction and higher blood pressure than white men, even when accounting for other variables that may affect blood pressure such as weight.

Seeing how blood vessels react—or overreact— to nervous system activity helps scientists understand more about the factors that potentially increase the risk of hypertension in black adults. The next step is to find ways to reduce these responses and lower the risks of hypertension and heart disease in this population.

April is National Minority Health Month. Visit the U.S. Department of Health and Human Services’ Office of Minority Health to learn how people from diverse cultures can stay healthy.

Yasina Somani cropYasina Somani, MS, is a PhD student in the Cardiovascular Aging and Exercise Lab at Penn State. She is interested in studying the effects of novel exercise and nutritional therapies on cardiovascular outcomes in both healthy and clinical populations.

Unusual Allergies: Water, Exercise, Sun and Cold

young woman has enlarged lymph nodes

Credit: iStock

As a graduate student rotating through medical clinics, I once heard a patient say, “Good morning, I think I am allergic to water.”

At the time, the idea of a water allergy seemed absurd to me. But as the human body constantly tries to adapt to a rapidly changing world, unusual allergies are cropping up everywhere.

Up to 50 million Americans, including millions of kids, have some type of allergy. Allergies occur when your immune system overreacts to a foreign substance called an allergen. Allergens cause symptoms that range from sneezing and watery eyes to body rashes and, in severe cases, a life-threatening reaction called anaphylaxis. The best way to control allergies is to avoid or remove the allergen and to treat symptoms.

While it’s not really possible to be allergic to your job—sorry about that!—it may not be your imagination if you think you are allergic to your shower. The most common allergens are food, drugs, pollen, dust and mold, but you can also develop unusual allergies to all kinds of common things, including:

  • Water: Up to 60 percent of the human adult body is water, so it is surprising that you can be allergic to it. Aquagenic urticaria is an incredibly rare—and untreatable—syndrome where the skin erupts in rashes whenever it comes in contact with water. Tears can even trigger symptoms in some people. In severe cases, people with this disorder can have trouble breathing after drinking water.
  • Exercise: Some people are truly allergic to exercise, experiencing severe itching approximately 30 minutes after working out. One type of exercise allergy called cholinergic urticaria seems to be triggered by sweat. Others such as exercise-induced angioedema cause symptoms no matter how intense the physical activity is.
  • Sun: Overexposure to the sun can cause sunburn and other damage in most people. But people with photodermatitis have skin so sensitive that even the mildest exposure causes skin rashes. Those with this disorder must spend most of their lives in darkened areas, going out only at night.
  • Cold: Fifteen to 25 percent of Americans are allergic to the cold (cold urticaria). People who have intense physical reactions to low temperatures may experience skin rashes and hives, swelling, fatigue, anxiety and headaches. Wheezing or trouble breathing may also occur, but these potentially dangerous symptoms are very rare.

Scientists are working hard to eradicate the symptoms and to improve quality of life for people with allergies both common and rare. In Dr. Patricia Silveyra’s lab, we investigate the effect of allergens and environmental pollutants on lung inflammation to develop therapeutic treatments for respiratory diseases.

Nathalie Fuentes OrtizNathalie Fuentes is a PhD candidate in the biomedical sciences program at Penn State College of Medicine. Her studies in Dr. Patricia Silveyra’s lab include the development of sex-specific therapies to treat lung diseases, sex differences in asthma-related lung inflammation triggered by ground-level ozone and the role of male and female sex hormones in lung disease. Nathalie is originally from Caguas, Puerto Rico.

 

Take Care of Yourself while You Take Care of Your Garden

Taking a break from all the work

Credit: iStock

Springtime signals warmer weather and, for many people, more time outside. A garden can be a great place to get sunlight (to support vitamin D production), physical activity and delicious fresh fruits and veggies. When you go out to plant, water and weed your garden this year, keep an eye on how well-watered you are to prevent yourself from getting dehydrated.

Gardening is a hidden form of exercise because you squat, bend and stand without even thinking about it. But the constant changing of positions requires your body to perform a complex balancing act. Every time you stand up, your blood vessels coordinate a rapid sequence of expansion (dilation) and narrowing (constriction) to keep the blood pumping around your body and to your head. The body uses a feedback system called the baroreflex to prevent your blood pressure from getting too high or too low. However, dehydration makes it more difficult for our baroreflex to regulate blood pressure.

Gravity pulls blood from your head toward your feet to regulate blood pressure, making standing up a challenge to the cardiovascular system even in moderate temperatures. It becomes more difficult— particularly for older adults—to be out in the hot sun without drinking enough fluids. When you do not drink enough water, there is less fluid moving through your bloodstream. This can cause blood pressure to dip too low. Blood pressure needs to be high enough to keep your blood flowing to the head to prevent dizziness and fainting.

To avoid passing out when you are picking flowers or tomatoes, keep water nearby to drink. Don’t wait until you feel thirsty to drink—you can lose up to 10 percent of your blood volume before you feel thirsty. Drink water before going outside, sip a cold beverage frequently while you’re out in the heat and continue “watering” yourself after you come inside.

Enjoy the outdoors and the (literal) fruits of your labor this spring, but do so with a water bottle in hand.

Joseph WatsoJoseph C. Watso is a doctoral research fellow in the department of kinesiology and applied physiology at the University of Delaware. Watso is interested in studying the role of lifestyle habits, such as diet and exercise, in maintaining heart and blood vessel health throughout aging. 

 

 

 

Skip the Nightcap: Your Sperm or Eggs May Thank You

Alcoholic Beverages

Credit: iStock

Alcohol may grease the wheels in the short-term and make trying to get pregnant a little more fun, but in the it long run it could throw a wrench in fertility. Roughly 10 percent of men and women in the U.S. report having difficulty getting pregnant. Worldwide, close to 49 million couples were considered to be infertile. Age, weight, smoking status, caffeine intake and fitness level can affect fertility. Moderate-to-heavy drinking can also lead to fertility problems in some people.

The Centers for Disease Control and Prevention defines moderate drinking as one drink per day for women and two for men. Heavy drinking is considered eight drinks or more per week for women and 15 for men. Drinking heavily may disrupt the endocrine system, which controls the hormones essential for healthy reproduction. This disruption may lead to decreased fertility in both women and men.

Long-term drinking may increase the amount of follicle stimulating hormone (FSH) circulating in the bloodstream in women. FSH naturally rises and falls throughout the menstrual cycle and is needed to maintain regular periods and ovarian function. Drinking may also reduce the number of follicles in the ovaries. Ovarian follicles contain the eggs that are released during ovulation. Fewer eggs being released and having irregular periods reduce the chances of getting pregnant each month.

Long-term alcohol use doesn’t just compromise fertility in women. Sperm health may also be affected. Alcohol may lower testosterone and progesterone—hormones that control sperm production and function—in men. Low levels of these hormones may lead to a lower sperm count and less mobile sperm.

Fortunately, not everyone who drinks will have trouble conceiving. Some studies have shown no association between alcohol and infertility, and research even suggests that a bit of wine may shorten the time it takes to get pregnant. So, if you’re trying to get pregnant, limiting yourself to an occasional glass or two of wine may be a good addition to your fertility checklist.

April is Alcohol Awareness Month. Visit the National Council on Alcoholism and Drug Dependence to learn more about boosting public awareness of alcohol-related problems.

Gilman_BigMamma2Casey A. Gilman, MS, is a PhD candidate in the Organismic and Evolutionary Biology graduate program at the University of Massachusetts Amherst. She was the 2016 American Physiological Society-sponsored AAAS Mass Media Science and Engineering Fellow at The Philadelphia Inquirer. Gilman’s research focuses on the postcopulatory sexual selection in lizards. She is also a freelance writer.

 

Food, Friend or Foe: How Our Gut Recognizes Good from Bad

Knight Riding to the Castle Gate

Your gut is like a well-fortified Medieval castle. Credit: IStock

Think about the last time you ate an apple—from the apple’s perspective. Pulverized in your mouth and dunked in a cauldron of stomach acid, the fruit slowly passed through the intestine before its final, unceremonious exit. Digestion is a wild, wacky journey.

Scientists study how the body can both absorb life-sustaining nutrients and keep out harmful invaders. Understanding this balance—and how it can get thrown out of whack—could lead to better treatments for digestive diseases.

Most of the nutrients from food we eat get absorbed in the intestine, which is home to a vast population of bacteria known as the microbiome. These bacteria help break down complex particles that we can’t, such as the fiber in fruits and vegetables. But some gut bacteria, known as pathogens, cause disease. The immune system’s job is daunting: It must protect us from pathogens without targeting healthy gut bacteria or food particles.

The first line of defense is the barrier of cells that line the intestine. These immune cells allow only small particles to pass through, making the intestine a bit like a medieval castle: A small rat can slip through the walls, but people have to get past the guards. This castle has a moat, too: a slippery layer of mucus that keeps organisms from getting too close. And no castle is complete without archers staffing the walls. Immune cells fire off proteins called antibodies that stick to gut bacteria to prevent them from attacking the body.

The immune system also learns to tolerate common foods and gut bacteria so it can recognize them as harmless and unlikely to cause disease. Researchers are studying exactly how this works, but they think that the intestine is naturally wired to permit most foods and beneficial bacteria.

Sometimes, however, the immune system commits friendly fire and attacks the body when it shouldn’t. Two common examples are celiac disease, an immune response to gluten, and inflammatory bowel disease, a response to the microbiome in the gut. Scientists are not sure why people get these diseases, although some studies suggest that specific genes may be involved. But it’s clear that more research is needed to reveal the secret of how the immune system distinguishes food and friend from foe.

Jonathan Wosen 2Jonathan Wosen is a PhD candidate in immunology at Stanford University, where he studies how the cells that line the intestines communicate with the surrounding immune system. Wosen was the 2017 American Physiological Society-sponsored AAAS Mass Media Science and Engineering Fellow at STAT News, a national science news publication based in Boston.