The Brain in Your Gut

Relation of human brain and guts, second brain

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Did you know your gut has a brain of its own? It’s called the enteric nervous system. The brain in your gut is embedded in the wall of the digestive tract. Together with your “big brain,” the enteric nervous system helps control gastrointestinal function, including the mixing and grinding of food in the stomach and absorption of nutrients in the intestines.

An adult’s enteric nervous system is made up of 200 to 600 million nerve cells (neurons). That’s as many neurons as are in a cat’s brain or even your spinal cord! The neurons in the enteric nervous system interact with smooth muscle to move food through the digestive system. The brain in your gut also plays an important role in regulating your immune system. It attacks bacteria and viruses (pathogens) that invade the digestive tract by releasing protective substances called peptides that make it harder for pathogens to do harm.

Although the brain in your gut functions independently from the “big brain”—and is the only organ in your body that can do so—normal digestive function requires communication between the enteric nervous system and the brain. The enteric nervous system provides sensory information to the brain to help you decide what, when and how much you eat. When you’re hungry or see something you’re craving (like a piece of chocolate cake or a juicy burger), your brain tells your gut to start the digestion process by producing gastric secretions in the stomach.

Problems with the enteric nervous system can lead to different digestive diseases such as irritable bowel syndrome and functional constipation. Studies have demonstrated that losing some of the neurons in the gut can be a cause of these conditions. Understanding how and why these neurons die is an important topic of research that could result in finding new treatments for digestive diseases.

To learn more about digestive disease, visit the National Institute of Diabetes and Digestive and Kidney Diseases website.

 

Ninotchska DelvalleNinotchska Delvalle is a doctoral candidate in the neuroscience program at Michigan State University. Her research focuses on how specialized cells of the enteric nervous system (enteric glia) contribute to the development of gastrointestinal disease.

Myasthenia Gravis May Be (Literally) All Greek to You

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Myasthenia gravis is a disease that affects the way that muscles receive signals from nerves. Myasthenia is Greek for “muscle weakness,” which is a good description of this disease’s symptoms. Muscle weakness, which worsens after physical activity but gets better with rest, is the primary symptom of the condition.

Weakness may occur in any skeletal muscle, but smaller muscles in the face are commonly affected. This leads to symptoms that may include:

  • difficulty chewing or swallowing,
  • speech impairment,
  • altered facial expression,
  • drooping eyelids, and
  • blurred vision.

Weakness in the limbs is often a symptom when larger muscles are affected. One of the most serious consequences of myasthenia gravis is a myasthenic crisis, which occurs when the respiratory muscles that allow us to breathe are affected. Someone in myasthenic crisis may need a machine (ventilator) to help them breathe if they have trouble on their own.

An understanding of how nerves work with muscles is important to understanding the effects of myasthenia gravis. The brain sends signals through the nerves, telling them which direct body parts to move. The signals travel down nerves to nerve endings, which are located very close to—but not touching—muscle fibers. Nerves release chemicals called neurotransmitters to send signals that bridge the gap between the nerves and muscles. Neurotransmitters bind to molecules on the surface of the muscle cells (receptors) that send a signal inside the cell. Acetylcholine is a neurotransmitter that causes muscle movement when it binds to its receptor. The normal interaction between a neurotransmitter and receptor doesn’t always work as smoothly as it should. In some cases, the immune system interferes, producing proteins called antibodies that are meant to protect the body from substances that might harm it. In the case of myasthenia gravis, the immune system makes antibodies that bind to acetylcholine receptors, which prevents the interaction between the neurotransmitters and receptors.

The disease typically occurs in women under 40 and men over 60, but it can develop at any age. Myasthenia gravis may be debilitating, but the good news is that symptoms can usually be controlled with medication. Steroids can help limit the production of antibodies that target acetylcholine receptors. Drugs called acetylcholinesterase inhibitors increase muscle strength by slowing the breakdown of acetylcholine. When neurotransmitters remain for longer periods of time, signals to the muscles are more likely to go through.

As you enjoy the outdoors and weather during Myasthenia Gravis Awareness Month, keep in mind all the things your muscles and nerves are doing without you even thinking about it.

 

Rebekah Morrow 3Rebekah Morrow, PhD, is an assistant professor of immunology and microbiology at the Alabama College of Osteopathic Medicine.

Like Father, Like Son (and Daughter): How Your Dad’s Past Affects Your Future

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What makes your father the best dad in the world? Maybe it’s his sense of humor or the times he has taken you to the movies or played catch in the yard. Or maybe it’s the fact that he made healthy lifestyle choices before you were born. Recent research suggests that your father’s health before you were conceived (preconception) may change the way your genes behave to affect your future health. It almost sounds like something out of a science fiction movie, but it’s real.

Studies tend to focus on the mother’s preconception health and the risks her baby might face later in life if she’s overweight. But a dad’s weight and early eating habits can also play a role, according to research published in the American Journal of Stem Cells. Researchers found that offspring of men who were obese before reproducing were more likely to have diabetes and be overweight. On the other hand, the researchers also found that fathers who had limited food resources in their early life caused genetic changes that protected their children—and even grandchildren—against cardiovascular disease.

Most people know that exercise is one of the healthiest lifestyle choices you can make to maintain your weight and keep your heart and even your brain healthy. However, research presented at the APS Integrative Biology of Exercise 7 meeting showed that offspring of men who exercised long term before conceiving had a higher likelihood of being obese and developing diabetes. This result was a huge surprise to the research team, but is it a reason to stop exercising? Not really. The study focused on how efficiently the body used energy on a high-fat diet. Limiting dietary fat and being active is still the way to go for most people.

Keeping stress levels low is also a good plan for dads-to-be. One study suggests that a man’s preconception stress may program his kids for mood disorders. Researchers found a pathway in the brain that transmits signals about stress hormones, and it may be passed down to the next generation.  If the signal is passed on to you, then your father’s stress levels could affect your predisposition for anxiety and depression.

These studies represent clues to learning how genetic material is transformed as it passes through generations. It’s also a reminder that following a healthy diet, staying active and maintaining mental health is important for everyone at every age.

Happy Father’s Day!

– Erica Roth

A Healthy Diet: A Prescription for a Healthy Life!

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We have all heard the phrase “You are what you eat.” Not only is there a lot of truth in that little saying, it is also a great reminder for us to be aware of everything we put into our bodies. Everything we eat and drink has an effect on our being and our physical and mental health depends on proper nutrition.

Most people know that nutrition means getting the right amount of nutrients to fuel our bodies and brains. But the difference between the types of nutrients can be less clear.

Nutrients are divided into three categories: micronutrients, macronutrients and water.

Micronutrients are vitamins, minerals and substances such as sodium and potassium called electrolytes. They are essential for growth, development and normal cellular activities. A wide variety of fruits, vegetables and animal products such as meat and dairy are rich in micronutrients.

Macronutrients include carbohydrates (sugar and starches), protein and fats. Macronutrients are extremely important because they give us the calories we need to produce energy. Each person needs a different amount of macronutrients depending on their body size, body composition and level of physical activity. This last point—activity level—is key. We often eat and drink far too many calories for our body’s needs and store the extra calories as fat. The excess fat can become a big problem, causing inflammation, problems with metabolism and cardiovascular issues.

Water is important for maintaining your body’s fluid balance and for functions such as digestion, circulation and body temperature. We also need water to carry nutrients throughout our body and to energize our muscles.

The lack of proper nutrition is still an issue in areas of the U.S. and other Western countries. However, consuming too many calories without enough nutrients is also a critical health problem in the developed world. In fact, the definition of “malnutrition” has been updated to include overnutrition. The expanded definition of malnutrition highlights the serious threat that overnutrition and obesity have on human health.

If you want to learn more about how to fit better nutrition into your life, visit the U.S. Department of Agriculture’s Choose My Plate website. This tool can help jump-start your nutrition knowledge and get you on your way to feeling great.

Audrey Vasauskas

 

In May, Take Steps to Prevent Melanoma

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With the weather getting warmer, you may be tempted to bare more skin in the coming months. However, sunnier days can increase your risk of skin cancer if you don’t protect yourself. May is Melanoma/Skin Cancer Detection and Prevention Month. Read on to learn more about your body’s largest organ and how melanoma grows.

Your skin is composed of three main layers: the layer that you see (epidermis), the layer directly beneath the epidermis (dermis) and the deepest, innermost layer (hypodermis). Melanoma, the most dangerous form of skin cancer, starts with an abnormal growth of cells at the bottom of the epidermis layer of the skin. These cells, called melanocytes, produce melanin to give skin its color.

Exposure to the sun’s ultraviolet (UV) rays is a major risk factor for developing melanoma. Even just a handful of blistering sunburns during childhood or adolescence can double your risk of developing melanoma later in your life. UV exposure can damage and cause mistakes (mutations) in the DNA of the melanocytes. UV-related mutations that occur in molecules important for controlling cell growth can lead to skin cancer.

Although only about 5 percent of all skin-related cancers are melanoma, it’s the deadliest form, causing approximately 10,000 deaths per year in the U.S. People with melanoma that is confined to a small area (primary melanoma) have close to a 90 percent survival rate. However, the recovery rate is significantly lower in melanoma that starts in the skin and spreads to other parts of the body (metastatic melanoma).

Metastatic melanoma most commonly spreads to the liver, lungs, bones and brain. This is troublesome for several reasons. Once cancer has spread, it is extremely difficult to determine the original cancer type, making treatment problematic. Also, cancer cells compete with normal cells for nutrients. Because cancer cells grow quickly, the body often ends up sending more nutrients (sometimes unintentionally) to the cancer, allowing its size to further increase. Early detection of melanoma is extremely important, giving you the best chance for treatment and survival.

Visit the Skin Cancer Foundation to learn how to reduce your risk of developing skin cancer.

 

Adam Morrow

Adam Morrow, PhD, is an assistant professor of biochemistry at the Alabama College of Osteopathic Medicine.

Walking and the Brain, Aromatherapy for Horses and a Whole Lot More!

Physiology, the study of function from microscopic cells to complete organ systems, encompasses a wide range of fascinating topics. The annual Experimental Biology (EB) meeting is a showcase for thousands of researchers studying humans and animals alike. Check out some of the research presented at last month’s meeting in Chicago:

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Most people know that walking is good for heart health, weight management and flexibility. New research from New Mexico Highlands University reveals how your brain also benefits from walking. Each step you take sends pressure waves through your arteries and increases blood flow—and oxygen—to the brain. The researchers found that running also had a beneficial effect on blood flow, while sports like cycling that don’t involve foot impact were less likely to make a significant difference.

Dressage test

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Do you like the calming scent of lavender when the pressure’s turned up? Turns out, you’re not alone. Research out of Albion College studied the effects of aromatherapy on horses. Much like people, competition horses get stressed out when they’re transported from their home to an unfamiliar venue. Stress reduction therapies are highly regulated in competition horses, and non-medicinal treatments could go a long way to calm the animals before they perform. The researcher found that stress hormone levels dropped significantly among trailered horses that were exposed to lavender aromatherapy when compared to distilled water mist.

Two women rowing on a lake

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Olympic-caliber athletes appear to be the picture of strength and power. But new research suggests that high-intensity workouts without a proper recovery period could interfere with optimum bone health. A study of female Olympic rowers from Canada’s Brock University showed that the levels of a protein that stops bone mineral loss dropped during extended periods of heavy training. Bone mineral loss weakens the bones and increases the risk of stress fractures and osteoporosis.

These studies just scratched the surface of all the top-notch physiology research presented at EB. Read more highlights from this year’s meeting:

Why vitamin A and a high-fat diet don’t mix

The role of immune cells in the cause—and treatment of—preeclampsia

How an ice bag on the face can help treat severe blood loss

An “exercise pill” may be in our future

How orange essential oil reduces PTSD symptoms

 

Erica Roth

April Showers Bring May Flowers—and Sneezes

Allergy Sufferers

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There are plenty of things to love about spring. It’s warmer and daylight lasts longer, so you can spend more time outdoors. It’s the end of cold and flu season, so you may be feeling better than you did over the winter. And it seems that everything is in bloom. However, those beautiful spring flowers and trees can cause their own problems in the form of seasonal allergies.

Pollen is the cause of most seasonal allergies. Pollen counts increase in the spring as trees and plants wake from winter dormancy. Trees and other plants release pollen into the air as a method of fertilization (pollination) to produce seeds and fruit.  Pollen travels as tiny particles (particulates) similar to dust. Every time you inhale, you breathe in a lot of particulates. Most of them are not harmful, but if you have seasonal allergies, your immune system reacts to pollen and makes an immune response against it. This immune response happens because your body—rightly so—thinks of pollen particulates as invaders. To fight these invaders, your body makes an inflammatory substance called histamine, which causes the itchy and watering eyes, sneezing and runny nose that are the hallmark symptoms of seasonal allergies. Your body is trying to keep you safe, but ends up making you miserable.

Many anti-allergy medications can help reduce allergy symptoms. Most of them do this by limiting the release of histamine from the immune cells inside your body. You can also reduce your symptoms by:

  • steering clear of outdoor activities as much as possible when pollen counts are high,
  • wearing sunglasses outdoors to help keep pollen out of your eyes,
  • changing your clothes after being outdoors, and
  • keeping the windows and doors closed in your home to limit the amount of pollen coming in and spreading around inside.

The best thing about seasonal allergies is that they are time-limited. Most plants have limited blooming seasons. As soon as the pollen counts drop, you can breathe easy and enjoy spring outdoors again.

 

Rebekah Morrow 3Rebekah Morrow, PhD, is an assistant professor of immunology and microbiology at the Alabama College of Osteopathic Medicine

Desperately Seeking Kidneys: New Future for the Treatment of Chronic Kidney Disease?

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The kidneys are an important pair of organs responsible for filtering water and waste out of the blood to produce urine. They help regulate blood pressure and produce hormones that the body needs to function properly.

Kidney disease is often considered a silent disease because there are usually no detectable symptoms in the early stages. Fourteen percent of adults in the U.S. suffer from chronic (long-term) kidney disease (CKD). Risk factors that can lead to CKD include diabetes, high blood pressure, aging and family history of kidney failure. African Americans, Hispanics and Native Americans have a higher risk of developing CKD.

When CKD progresses to kidney failure—also called end-stage renal disease—the only treatment options are dialysis or kidney transplant. People who receive dialysis are hooked up to a special machine that removes waste and excess water from the blood. It effectively acts as an artificial kidney outside the body. But dialysis is time-consuming. People in kidney failure need to have dialysis several times a week to survive. A kidney transplant requires a matching donor and comes with its own risks, including that transplantation is a major surgery and there is a possibility that the kidney(s) will be rejected.

Currently, there is no drug treatment to stop the progression of CKD. Researchers at the University of Mississippi Medical Center recently published a study in the American Journal of Physiology—Renal Physiology about a new treatment option. A man-made carrier system called elastin-like polypeptide (ELP) complex can be used to deliver a drug directly to the kidney to stop CKD from getting worse.

The ELP system is a new possibility for diseases like CKD that don’t seem to respond to traditional treatments, offering hope to people with kidney failure. The technology has only been studied in animals so far, but research suggests that targeted therapy could be a new frontier for the treatment of kidney disease.

 

Megan RhoadesMegan Rhoads, BS, is a doctoral candidate in the Department of Biology at the University of Kentucky.

 

When’s the Best Time to Eat? Your Body Clock Knows

 

Two teenager girls, sisters, eats fastfood on the street

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The American Heart Association recently released a statement suggesting that when and how often you eat could affect your risk for developing heart disease and stroke. Until now, the focus on diet has been primarily about how much and what you eat. This news—that the time of day you eat may also be important—could change the way people are able to manage their health.

Our bodies have natural daily patterns called circadian rhythms that occur roughly over a 24-hour cycle. Many biological processes are driven by circadian rhythms, including when you go to sleep and wake up, your body temperature, heart rate, blood pressure and the release of various hormones. A “master clock,” a tiny group of cells called the suprachiasmatic nucleus (SCN), located in the hypothalamus area of the brain manages circadian rhythms. This master clock is mostly controlled by changes in light.

Every cell in the body also has its own internal clock called a “peripheral clock.” Peripheral clocks make sure all of the cells’ functions are coordinated with the master clock. Animal studies show us the importance of keeping peripheral clocks in sync with the brain’s master clock. For example, when the peripheral clock in a mouse’s heart is disrupted, the mouse develops heart failure and dies at a much younger age than normal mice.

Unlike the master clock, peripheral clocks are more responsive to the availability of food than changes in light. As a result, eating at the “wrong” time of day could shift the rhythms of the peripheral clocks so they are out of sync with the master clock. For example, shift workers who work in the middle of the night are active when they would normally be asleep and eat at times when their body doesn’t expect food. They are at much greater risk for being overweight, becoming insulin resistant and developing cardiovascular disease because their master and peripheral clocks are likely to be out of sync.

Research in mice has shown that if they consume a high-fat meal at the end of their active period (the equivalent of a high-fat dinner for humans) they gain more weight, develop insulin resistance and have impaired cardiac function compared to mice that eat the same high-fat meal at the beginning of their active phase (breakfast).

Studies in people suggest that eating meals late in the day is linked to negative health effects, but a direct relationship has not been shown. Nevertheless, if when you eat is just as important as what you eat, it might not hurt to eat your larger meals earlier in the day if you can.

 

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.

How Obesity Fuels Inactivity

 

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More than one in three adults and one in six children in the U.S. are obese. Obesity—defined as a serious degree of overweight—is a leading cause of death, disease and disability. Although obesity has been linked to genetic disorders, it is most often caused by unhealthy behaviors and, therefore, is preventable and reversible.

Throughout the day, we get calories from food and we burn the calories off when we move our bodies. When we eat more calories than we burn, our bodies store the excess calories as fat, which accumulates over time. Eating too many calories and not moving enough are two factors that can cause obesity. Only one in five adults in the U.S. meets minimum physical activity recommendations, making physical inactivity a significant contributor to obesity. People who are overweight need to eat fewer calories and/or increase physical activity to lose excess fat. These lifestyle changes are often challenging, and may be compounded by the fact that exercise may be harder to do when you’re obese.

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 The cycle of obesity. Credit: Kim Henige

Carrying excess body weight can make joint pain more likely, which makes physical activity more difficult. Now, researchers may have discovered another reason excess body weight makes physical activity more difficult. A recent study published in the Journal of Applied Physiology shows that the working muscles of obese mice tired out more quickly than those of lean mice. These findings support a cycle of obesity where inactivity leads to obesity, which leads to more inactivity. Breaking the negative cycle of obesity and re-establishing a healthy body weight is possible, but takes considerable dedication and persistence to overcome the barriers and discomfort of the process.

Remember that the path to a healthier weight starts by taking a step! Visit the Centers for Disease Control and Prevention website for weight loss strategies, success stories of people who’ve lost weight and kept it off and more.

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.