Sugars, Fructose and Your Health

sugar

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Early humans were probably jacks of all trades when it came to food—they ate what was available, and the amount of carbohydrates, proteins and fats in their diet varied dramatically depending on where they lived. Except for honey, there were likely no sweeteners to “spice” up their meals. That all changed 200 years ago when table sugar—a combination of the sugar molecules glucose and fructose—began to be manufactured. This provided a steady supply of inexpensive sweeteners to the general population. From that time on, the amount of sweeteners humans ate began to rise drastically. It’s no coincidence that obesity and diabetes rates increased a few decades later. The cost of sweeteners were further reduced (and the availability increased) with the introduction of high-fructose corn syrup (HFCS) 40 years ago. HFCS is a processed form of glucose that can be easily added to many beverages and foods.

High sugar intake may cause physiological changes in the body that can interfere with the way organs are supposed to function and the way the body burns energy (metabolism) attained through food. The average non-obese person has a very low blood fructose concentration that may be as much as 100 times lower than blood glucose levels. Consuming fructose-laden desserts and sodas quickly increases blood fructose levels, flooding liver cells that are not used to such high doses. Fructose is rapidly broken down into easily processed substances (metabolites) that can be building blocks for fats.

Consuming a lot of fructose often leads to a marked increase in fat-forming enzymes and fatty deposits in the liver.  Coincidentally, a decade after HFCS was widely introduced, a new metabolic disease—nonalcoholic fatty liver disease (NAFLD)—cropped up. NAFLD has been linked to overconsumption of fructose and added sugars. A fatty liver is associated with high triglycerides and “bad” cholesterol, increasing the risk for cardiovascular disease and obesity.

The good news is that these associations between added sweeteners, particularly fructose, and metabolic diseases have resulted in serious efforts to reduce consumption, like Mexico’s tax on sugary drinks and New York City’s (unsuccessful) attempt to ban sales of large sodas. In light of these efforts, people in the U.S. now seem to be eating less added sugars.

It is important to remember that moderate consumption of added fructose is most likely fine for most people. Fructose is the sweetest of the naturally occurring sugars and a little goes a long way. This is one case where “less is more.”

Ronaldo FerrarisRonaldo Ferraris, PhD, is a professor of pharmacology, physiology & neuroscience at the New Jersey Medical School at Rutgers University.  He studies intestinal epithelial biology and cell differentiation as well as integrative regulatory processes involving sugar sensing, transport and metabolism in the small intestine.

Dog Gazing: Attachment between Hound and Human

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While walking through Santiago, Chile, you are likely to come across at least one of the countless wandering dogs that live on the busy streets. Homeless dogs are a normal part of Santiago’s culture. They are quick to make friends with anyone who offers a welcoming hand or food. They are not quick, however, to forget their friends. If you make a canine companion in this city, as my classmates and I did, it will probably remember you the next time you come down the street.

The feeling of attachment between the dogs and people of Santiago reminded me of the way a mother and her infant gaze into each other’s eyes. This simple, mutual act of love causes an automatic reaction in both the mom and baby, which increases the levels of oxytocin in the body. Oxytocin is a hormone that plays a major role in social bonding between mothers and infants and between romantic partners. The release of oxytocin promotes a feeling of social well-being and may prevent stress. Interacting with the local dogs in Chile made me wonder if this same sense of happiness and bonding occurs between dogs and people.

A research study looking at the bond between humans and dogs found a similar release—and increase—of oxytocin during social interactions, such as gazing, in both the animals and people. The dogs’ hormone levels also increased when people talked to and petted them. Scientists think this looped interaction reaction (bonding in both directions between pooch and person) may be a reason that humans were able to domesticate wild dogs in the first place. Dogs are one of the only animals known to fully recognize human facial features and expressions. This ability likely helps dogs and people communicate, love and take comfort in one another’s presence.

This mutual interaction is likely the cause of a quick, yet memorable, friendship between humans and dogs both at home and in places like the streets of Santiago. So next time you see a dog in passing, don’t be afraid to gaze into its eyes and form a quick friendship.

 

goff black white dogLogan Goff is an exercise physiology major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes studying nutrition, sports and research in the context of the Chilean culture. This is the final installment in a three-part series (read part one and part two) that spies physiology in this dynamic South American country.  

 

 

 

When Hormones Take Your Breath Away

Pretty woman using her inhaler

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After a healthy childhood, my best friend suddenly started having breathing difficulties when she was 20 years old. The doctor diagnosed her with asthma. With the help of inhaled medications, she was able to control her symptoms. But a year later, the medications were no longer effective and she started having monthly, life-threatening asthma attacks. The severe attacks became more frequent a few days before her menstrual period, and the symptoms disappeared days after her period ended. At that time, I wondered if hormones could be to blame.

As a graduate student investigating the role of male and female hormones in lung inflammation, I know now that asthma can be a hormone-related health issue. Unfortunately, many people are unaware of this relationship. Hormones are chemicals that travel as messengers around the body through the bloodstream. They affect many bodily functions and play a large role in a woman’s life cycle from birth through puberty, adulthood, pregnancy and menopause. In proper balance, hormones help the body communicate and thrive. But sometimes hormone levels can be too high or too low, causing serious health problems, especially in people with asthma.

Although more young boys have asthma than girls, the pattern is reversed in adults: More women have asthma than men. During puberty girls begin to produce higher levels of the sex hormones estrogen and progesterone, which rise and fall throughout their menstrual cycle. About one-third of females with asthma report premenstrual-related asthma symptoms, which may lead to severe attacks. A research study of girls ages 8 to 17 found that those who started menstruating at earlier ages developed more severe asthma after puberty, perhaps because their hormone levels began to change earlier in life. Studies have shown that hormonal changes can disturb the airways and inflammatory responses in the lungs. As hormone levels go up and down, new blood vessels in the lungs form and disappear, affecting the lungs’ ability to take in oxygen. In addition, female hormones do not just cause breathing problems in women with asthma, but also in those who smoke or are overweight.

Researchers are working to discover how sex hormones affect the lungs in order to develop personalized treatments for asthma. Ideally, specialized treatments in the future will be gender-specific and take into consideration a person’s hormonal status.

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.

 

 

Fact or Fiction: Does Coca Candy Prevent Altitude Sickness?

Trekker resting in height mountain

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This summer, I spent a month studying at the Universidad de los Andes in Chile. We visited the Atacama Desert, the driest non-polar desert in the world. It is nestled between two sets of mountains; during one of our excursions we hiked up the Andes Mountains to a village called Socaire, located at an altitude of around 11,000 feet above sea level.

Our site coordinator, physiology professor and “temporary mom,” Anne Crecelius, PhD, kindly offered us coca candy, hoping it might prevent the dizziness, nausea and headaches sometimes associated with altitude sickness. She had asked us to drink more water than we usually do, too, just in case anyone in our group responded badly to being so high up. Coca candy is made in part from coca leaves, a plant that local people have chewed on for thousands of years. Coca leaves contain chemical compounds called alkaloids, which have been shown to reduce hunger and calm the side effects of high-altitude travel.

The question remains whether coca really has physiological benefits. The research is mixed. Some studies, citing the uses of coca throughout history, claim that there are significant benefits to chewing coca leaves. They recount improved energy efficiency during exercise, boosted energy levels—similar to the effect of caffeine in coffee—and decreased thirst and appetite.

However, other researchers suggest that the effects of coca leaves are mostly psychological, similar to a placebo effect (using a fake treatment, or placebo, in a group of people to compare the effects with people using a real treatment). In some cases, the group taking the placebo will also see improvement in their condition.

Even if coca leaves do prevent altitude sickness symptoms, the candies we munched on did not contain enough coca to help much. But perhaps they were enough to create some sort of placebo effect in our group, as no one was sick, just a little out of breath. Nevertheless, we enjoyed the town, the candy and a snowball fight near a very old church. Who knew that a small town at high altitude could be so much fun? Most likely, the locals and generations of indigenous people, who also know of the power of coca.

Andrew KramerAndrew Kramer is an exercise physiology major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes, studying nutrition, sports and research in the context of the Chilean culture. This is the second in a three-part series that spies physiology in this dynamic South American country. Read part one.

 

Being Left (Handed) Is All Right

Little boy writing on green blackboard

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“There’s something I ought to tell you. I’m not left-handed either.” – Westley, The Princess Bride

Throughout history, left-handedness has both fascinated and frightened people. Maybe it is because only about 15 percent of the population is left-handed. Or maybe it is because the reasons for left-handedness remain somewhat of a mystery.

What makes a person left- or right-handed? It seems we can find the answer in our genes, at least partially. Most researchers in the field agree that left- or right-handedness is most likely produced by genetic influences. We inherit our genes from our parents, and the genes that are turned on determine our characteristics. The specific reasons behind these genetic differences are still hotly debated, but many studies seem to point to natural selection as a probable cause.

The human brain is divided into the right and left hemispheres, with nerve fibers connecting the two. Different parts of each half of the brain control different functions of the body. Many evolutionary biologists argue that evolution produced a majority of people who controlled language with their left brain, which also controls the right side of the body, including the right hand. As written language developed, people with genes toward right-handedness had a genetic advantage and passed those genes down to their children. But the question remains: Why are some people left-handed when natural selection seems to be evolutionarily “against” left-handedness?

Scientists have discovered that handedness is influenced by not just one, but a group of genes, and that these genes can be influenced by external and societal pressures. For example, if a person expresses the genes for left-handedness, they may be taught to write with their right hand. In the same way, a person who writes with their right hand can be taught to use their left hand to throw or shoot a ball for a competitive advantage.

Although it may be more difficult to find a pair of scissors or spiral notebook that are easy to use, left-handedness has its advantages. Left-handers have been shown to have greater coordination, and left-handedness has been linked to creativity, especially in men. This may be due to the connection with the right brain, which is the creative hemisphere. Many lefties excel in sports such as tennis and fencing, possibly because there are fewer left-handed opponents.

While research continues into what makes left-handed people unique, we can celebrate our left-handed friends now in honor of Lefthanders Day on August 13.

Audrey Vasauskas

Beer Does a Body Good?

Drinks: Beer Isolated on White Background

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Bone is a living organ that constantly breaks down and rebuilds itself. As we get older, bone breaks down more and rebuilds less, which often leads to weaker bones over time. If we lose too much bone, we increase our risk of fracture and developing osteoporosis.

Women tend to have weaker bones and a faster rate of bone loss—particularly after menopause—than men. Approximately 50 percent of women in the U.S. over the age of 50 will break a bone due to osteoporosis. If the broken bone is in the hip, there is about a 20 percent chance that the individual will die within one year. Breaking a bone in our later years can significantly affect quality of life and the ability to live independently. Therefore, it is important to do everything we can to minimize age-related bone loss.

Lifestyle choices can help minimize bone loss, including:

  • following a healthy diet with enough calcium and vitamin D;
  • participating in regular physical activity; and
  • refraining from smoking.

Believe it or not, drinking a beer now and then may even help.

Researchers in Spain have discovered a link between beer consumption and bone health in women. They found that women who drank moderate amounts of beer—defined in the U.S. as up to one 12-ounce beer per day—had stronger bones than those who did not.

Beer contains two important nutrients that could be beneficial to bone health: phytoestrogens and silicon. Phytoestrogens are naturally occurring nutrients in plants that act similar to the hormone estrogen. Estrogen protects women from bone loss, but levels drop significantly after menopause. Estrogen deficiency is the primary cause of bone loss after menopause. Silicon is a naturally occurring mineral that may be used as a supplement to reduce bone breakdown and increase bone rebuilding in women with osteoporosis. Beer is one of the most plentiful sources of silicon in the Western diet.

It’s likely that the combination of phytoestrogen and silicon in beer helps limit bone loss. This finding has potentially important implications for bone health, although more study is needed.

It is also important to remember that drinking too much alcohol has many negative health effects, including reduced bone strength. Keep beer intake at a moderate level. That said Aug. 4 is International Beer Day. Drink a toast to healthy bones!

 

Kim HenigeKim Henige, EdD, CSCS, ACSM EP-C, is an associate professor and undergraduate program coordinator in the department of kinesiology at California State University, Northridge.

 

Spinal Cord Injury: Let’s Clear the Air(ways)

Human Spine Anatomy

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The spinal cord is the information processing highway in animals (including humans) that have a backbone. In humans, the spinal cord contains nerve cells called motor neurons that control movement in the muscle fibers of the body, similar to the way a puppeteer controls the movements of a puppet.

About 17,000 people in the U.S. sustain new spinal cord injuries (SCI) each year, and roughly 300,000 people in the U.S. live with an SCI. Motor neuron damage in the spinal cord may lead to a variety of problems, including:

  • decreased mobility and independence;
  • loss of independent breathing;
  • injuries associated with using a wheelchair, such as pinched nerves and muscle strain;
  • partial or total inability to control the bowels and/or bladder; and
  • sexual dysfunction.

New research is addressing all of these important problems, but one area that is not as widely studied is airway clearance. Most of the time we can clear our airways ourselves through coughing and sneezing, but these actions become more difficult with SCI. Close to half of all people with SCI have damaged the motor neurons that control their diaphragm, the muscle that sits below the lungs and helps us breathe. As a result, people with SCI have an increased risk of potentially fatal airway infections such as pneumonia.

Fortunately, about 90 percent of these injuries are incomplete, meaning that some of the neurons still function. People with incomplete SCI have some sensation below the injury site and can often breathe on their own. We only need 10 to 20 percent of our diaphragm muscle to activate in order to breathe, but almost the entire muscle needs to be functional to cough and sneeze. When the motor neurons controlling the diaphragm are injured, the organ isn’t able to generate the forces necessary to clear the airways fully.

Over time, the neurons in the diaphragm that still function in an incomplete SCI may adapt to take over other jobs besides just breathing. This is called neuroplasticity. Neuroplasticity in the spinal cord is a valuable topic of research.  Researchers are looking for new ways to manipulate this process to help people with SCI learn new airway clearing methods which would likely reduce their health risks and improve their quality of life.

 

obaid-khurram-15978141Obaid Khurram is a PhD candidate in the biomedical engineering and physiology program at Mayo Clinic Graduate School of Biomedical Sciences. His research focuses on the neuromotor control of the diaphragm muscle, particularly after motor neuron loss or muscle weakness.

 

What Animals Can Teach Humans about Muscle Maintenance

Hiding Groundhog

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We all know the saying “use it or lose it.” Your muscles and nerves are no exception. When people are not active, whether it’s because of bed rest, spinal cord and nerve injury, or other reasons, two big problems arise. First, the muscles shrink by losing protein (a state called atrophy). Second, nerve cells have trouble firing electrical signals to communicate with the muscles. This combination can make it harder for people who are inactive to perform normal activities in their daily lives.

Unlike in humans, inactivity in other animals is not always such a bad thing. Certain animals in the wild need to stay inactive (dormant) to survive in their environment. During times of low food availability and harsh environmental conditions, ground squirrels, frogs, bats, turtles and bears may remain inactive. In the winter, this is called hibernation, and in the summer, it’s known as estivation. Quite often, these animals’ muscles are less active than normal or completely inactive for several months at a time. Some frogs can even survive under water during the winter without using their breathing muscles. Based on the idea of  “use it or lose it,” you might think that hibernating animals wouldn’t be able to run, jump, fly or even breathe normally after months of not using their muscles. Think again!

Understanding how animals immediately return to using their muscles and nerves normally after long stretches of dormancy is a major area of research. By learning how different animals dodge neuromuscular problems related to inactivity, scientists can figure out why human muscles and nerves are not as well-equipped. For example, hibernating animals activate genes that reduce the loss of muscle protein and use less energy during periods of inactivity to avoid atrophy. These discoveries have the potential to provide new treatment options for people who are confined to bed rest or who suffer nerve injuries that leave muscles unable to contract.

Animals have already solved many problems that plague humans, such as nerve and muscle inactivity. Research that compares animal and human function is an example of comparative physiology. Comparative physiology findings can help scientists make important discoveries that would not be possible if the cures hiding inside animals were overlooked.

Joe SantinJoe Santin, PhD, is a postdoctoral fellow at the University of Missouri-Columbia.

 

Can Exercising in Low-Oxygen Conditions Help Breast Cancer Survivors?

Supporting each other in the race against breast cancer

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Physical activity has been linked to a lower risk of developing several types of cancer, including breast cancer. Walking a few hours a week may even decrease the risk of a breast cancer recurrence as well as dying from the disease. The American Cancer Society currently recommends that people recovering from cancer should exercise at least 150 minutes per week.

But people with breast cancer often face a number of challenges to establishing a regular exercise program. Chemotherapy and radiation can affect heart and lung function, and about 60 percent of breast cancer survivors have reduced strength in their legs as a result of a loss of muscle mass. In addition, more than 80 percent of women gain weight after a diagnosis of breast cancer. These factors, along with fatigue from treatment, can prevent breast cancer survivors from being as active as they want to be.

Knowing that exercise is beneficial for people with breast cancer but that they face challenges, researchers at the University of Alabama at Birmingham (UAB) are looking at new ways to improve breast cancer survivors’ response to exercise. Their study compares the effects of exercising under low-oxygen conditions—similar to that seen at an altitude of 7,000 feet—with exercising in normal oxygen conditions at sea level.

Elite athletes sometimes train in mountainous areas—between 5,000 and 8,000 feet above sea level—to improve their performance. The air at high altitudes is thinner and contains less oxygen. Lower oxygen levels help boost the number of red blood cells that carry oxygen around your body. Exercising at high altitudes also lets you train harder without the added stress on your joints and muscles that occur at sea level.

While it is impractical to take cancer survivors to the mountains, UAB researchers are trying to bring the mountains to the patients During exercise sessions, participants wear a mask that is connected to a machine that controls the amount of oxygen they breathe in. This mimics the low-oxygen levels of a high-altitude workout.

The study is ongoing, so it is too soon to know how beneficial exercising under lower oxygen levels will be. However, the researchers predict that exercising in low-oxygen conditions will trigger a number of physiological changes that will let people with breast cancer be more active and improve their overall health. If the results of the study are correct, it may lead to new approaches to help breast cancer survivors lead a more active life.

 
John Chatham

John Chatham, DPhil, is a professor of pathology and director of the Division of Molecular and Cellular Pathology at the University of Alabama at Birmingham.

Not Horsing Around: Therapeutic Effects of Horseback Riding

Anne with students and Paralympians

Anne R. Crecelius, PhD, and students visit with La Roja Paralimpica athletes in Chile.

Choosing your favorite part of a trip can be a difficult decision for travelers. I had countless unforgettable and unique experiences during a recent four-week trip to Chile. One excursion that stands above the rest was a weekend trip to San Pedro de Atacama in Northern Chile.

I was studying with a group of students who had booked a horseback riding tour through the oasis of Sequitor. With the Andes Mountains as our backdrop, we spent two hours enjoying the perfect blue sky, warm sun and crisp air. This small agricultural region is in what is often called the driest desert in the world.

I had never been horseback riding and did not realize how much coordination, strength

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Molly Gearin tries her hand at horseback riding.

and physical and mental stamina it required. I later learned that horseback riding is a type of rehabilitative treatment—called hippotherapy—that may improve coordination, balance and strength in people with physical disabilities, including cerebral palsy (CP).

CP is a neurological disorder that affects body movement and coordination. Studies have shown that hippotherapy can improve joint stability, balance and painful muscle contractions in people with CP. Children with CP may especially benefit from hippotherapy. Therapeutic riding can change how the abdominal and lower back (core) muscles respond to different movements. These physiological benefits can improve posture and the overall quality of life in some children, particularly among those who have the ability to walk, run and jump.

Researching hippotherapy was not the first time I thought about people with CP on our trip to Chile. Another favorite activity was our opportunity to watch La Roja Paralimpica, the Chilean Paralympic Fútbol 7-a-side team, practice. This sport is adapted from traditional fútbol (soccer) to accommodate athletes with disabilities. The modified rules allow Paralympic athletes to enjoy a sport that is at the heart of Chilean culture.

As a future physical therapist, I enjoyed observing elite athletes at work and learning about hippotherapy, an activity that could be of benefit to people with CP.

– Molly Gearin (Anne Crecelius contributed to this post)

Molly Gearin is a pre-physical therapy major at the University of Dayton. Anne R. Crecelius, PhD, is an assistant professor in the Health and Sport Science Department at the University of Dayton. They spent four weeks in Chile as part of a study abroad program in partnership with the Universidad de los Andes studying nutrition, sports and research in the context of the Chilean culture. This is the first in a three-part series that spies physiology in this dynamic South American country.