The Fat-blocking Powers of Fiber

Leafy green vegetables

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An estimated 610,000 people in the U.S. die from heart disease each year. One common cause of heart disease is the narrowing of blood vessels due to the buildup of fatty deposits (plaque). Many factors—including eating a lot of fatty foods—can lead to plaque buildup in blood vessels.

Your liver processes excess fat by packaging it into cholesterol droplets known as low-density lipoproteins (LDLs). LDLs travel throughout the body in the blood. Often, the droplets get stuck to the blood vessel walls, where they accumulate. The buildup of plaque eventually blocks blood flow, most often in the blood vessels that supply blood to your heart. However, eating fiber can help prevent the early stages of heart disease and plaque buildup.

Fiber is a plant’s supply of stored energy, but your gut can’t digest it. During a meal, your small intestine breaks down the food you eat and absorbs nutrients. Fiber resembles a mesh-like structure. Indigestible fiber acts like a large net—think of a butterfly net—to block places where fat can be absorbed. A meal high in dietary fiber blocks some of the absorption of fats, stopping fats from moving outside the gut into the bloodstream.

When there is less fat absorbed from your gut, your liver does not have to package it into LDL droplets, which lowers LDL levels in the blood. In addition, when your liver needs fat to make hormones and bile, it can produce another kind of cholesterol called high-density lipoproteins (HDL). HDL can remove some of the plaque in blood vessels and send it back to the liver. HDL is known as “good cholesterol” for this reason. Consuming meals high in fiber can help HDL with this process.

Recent studies have shown that eating fiber-rich brown rice or taking more than 5 grams of fiber supplements daily can improve some measures of cardiovascular function in adults. Leafy or green vegetables such as spinach, lettuce and broccoli are also good sources of fiber. So make a salad or try adding greens to an entree or a smoothie—I promise you can’t even taste blended spinach in a fiber-packed smoothie. There are plenty of options to fiber up your diet and keep your heart healthy.

Gabrielle RoweGabrielle Rowe is a PhD candidate in the physiology program at the University of Louisville. She is interested in studying small heart vessel function, stem cells and aging.

Spotlight On: Preeclampsia

Pregnant woman holding hands over belly on black background

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Lady Sybil Crawley—the feisty youngest sister of a wealthy British family on the PBS television series “Downton Abbey”—made her way into viewers’ hearts. Devotees of the show were shocked when, in a surprise twist, she died soon after giving birth. Lady Sybil died from high blood pressure during pregnancy (preeclampsia) that developed into a more serious condition called eclampsia in which high blood pressure causes potentially fatal seizures.

Unfortunately, this type of tragedy is not a distant memory from the early 1900s when “Downton Abbey” was set. Preeclampsia still causes too many deaths—or near deaths—in the U.S. each year. However, when diagnosed properly, preeclampsia is manageable.

Preeclampsia develops in about 5–8 percent of all pregnancies. Symptoms include headaches, nausea, vomiting, and excessive swelling of the feet, hands and face.

There are also invisible symptoms, such as damage to internal organs like the liver and kidneys. Preeclampsia occurs when a woman’s blood pressure rises too high (140/90 mmHg or above) during mid- to late-pregnancy (more than 20 weeks of gestation). The increased blood pressure limits the amount of blood that the baby receives and can slow down fetal growth. Babies born to women with preeclampsia are frequently smaller and weigh less than those born to women with normal blood pressure. Preeclampsia is often connected with other health conditions such as obesity, diabetes, kidney disease and a history of high blood pressure.

A woman’s age, race and where she lives can also increase the likelihood of developing preeclampsia. Women over age 40, black women and women from the southern U.S. also have an increased risk of developing high blood pressure during pregnancy. The reasons why Southern women have greater risk are not clear, but it may be linked to the prevalence of obesity and diabetes, especially in the Deep South.

It is important for expectant women and their families to know the symptoms of preeclampsia, talk openly with their doctors about their potential risks and speak up when something doesn’t feel right. May is Preeclampsia Awareness Month. Talk to the pregnant women in your life and learn about preeclampsia together.

Jessica Taylor, PhDJessica C. Taylor, PhD, is the Senior Manager of Higher Education Programs at the American Physiological Society. She is a cardiovascular physiologist, the mother of one and hails from Mississippi.

The Heart Adapts to the Sex of Heart Transplant Recipients

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Peter Kerkhof, PhD, presents his poster, “Sex-Specific Aspects in Cardiac Transplantation Evaluated by Left Ventricular Size in Male and Female Recipients” at Experimental Biology 2018. Credit: Nathalie Fuentes

Whether you are male or female can play a role in your health when it comes to how well you recover and thrive after an organ transplant. Because donated organs are in high demand, the sex of the donor is not taken into consideration when assessing compatibility. However, men and women who receive donated organs can respond differently after transplantation, including in cases when the immune system rejects the transplanted organ. For some people, organ rejection may be influenced by the sex of the donor.

The influence of biological sex on transplant outcome has not been thoroughly studied—even as more than 3,000 people in the U.S. are waiting for a heart transplant on any given day. Peter Kerkhof, PhD, and colleagues at VU University Medical Center in the Netherlands evaluated current knowledge about the impact of biological sex differences in heart transplantation and explored why there is a discrepancy between rejection rates for male and female recipients. Kerkhof presented his team’s research at Experimental Biology 2018.

The researchers analyzed computer tomography scans of 94 patients who had a heart transplant. Forty percent of the transplanted hearts were from male donors, and 60 percent were from females. The research team discovered that the left ventricle—which supplies most of the heart’s pumping power and is essential for normal function—in transplanted hearts is able to adapt to the new body in size and pumping power, even if the recipient was of the opposite sex.

The researchers saw evidence of this adaptation in the ejection fraction of the heart recipients. Ejection fraction compares the amount of blood in the heart to the amount of blood pumped out and was found to be smaller in all female recipients, even those with male donor organs. The smaller ejection fraction in women is similar to what occurs in healthy women when compared to men. Now more research is needed to learn about the mechanisms responsible for sex-specific adaptation in heart transplant recipients.

 

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.

 

Herbal Tea: Healthier Hot or Cold?

herbal tea

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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.

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.

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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.

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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.

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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

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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.

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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

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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

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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

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“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

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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.

Take Care of Yourself while You Take Care of Your Garden

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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. 

 

 

 

Curcumin, the Golden Spice

Family having Indian food

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Growing up, I enjoyed spending time in my grandmother’s kitchen. Her cooking usually involved an array of colorful spices, including a generous mix of curry powder in nearly every Indian recipe. You can’t mistake the tantalizing smell—cooking with this yellow-tinted powder can fill a room quite quickly. But it appears that there is much more to the aromatic spice than first meets the nose. It may help maintain heart health, too.

Turmeric, one of the spices that make up curry powder, contains curcumin. Evidence suggests that consuming curcumin has a wide range of physiological effects that may be beneficial to health. Curcumin is rich in antioxidants and acts as an anti-inflammatory, which may help explain its ability to promote nitric oxide (NO) availability. NO is a key compound in maintaining the health of our blood vessels. Scientists think that the body makes less NO and more becomes inactive as we age. Consequently, there is less available as we get older.

Also as we age, our blood vessels aren’t able to expand (dilate) as well. They become stiffer and less flexible and more likely to become clogged. Older people have a greater risk for developing high blood pressure due to the increased stiffness and reduced flexibility of the blood vessels. This process is called vascular aging. Women appear to experience vascular aging more quickly after menopause when the hormone estrogen is no longer produced.

A study of healthy middle-aged and older women in Japan found that taking curcumin supplements for eight weeks improved the blood vessels’ ability to dilate and reduced stiffening of the carotid artery in the neck. A recent study in the Journal of Applied Physiology found that exercise training alone does not protect against blood vessel stiffening in postmenopausal women. Therefore, combining exercise training with curcumin may be a promising way for women to slow down the steep decline in vascular health after menopause.

Another study of healthy middle-aged and older adults found that 12 weeks of curcumin supplementation improved NO availability and reduced oxidative stress (a type of cell damage) to improve blood vessel function.

These studies show promise for curcumin as a preventive therapy to lower heart disease risk in both men and women.

It seems that this golden spice really is a spice for life and may help prevent cardiovascular disease—the leading cause of death in the United States and worldwide—in older people.

March is National Nutrition Month. Learn more about how eating a balanced diet can improve your health at the Academy of Nutrition and Dietetics website.

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.