Does Yo-Yo Dieting Drive Compulsive Eating?

New research on rats seems to find a connection between yo-yo dieting and compulsive eating.

According to researchers at the Boston University School of Medicine (BUSM), a chronic cyclic pattern of overeating followed by undereating reduces the brain’s ability to feel reward and may drive compulsive eating.

The finding suggests that future research into the treatment of compulsive eating behavior should focus on rebalancing the mesolimbic dopamine system, the part of the brain responsible for feeling reward or pleasure, researchers say.

“We are just now beginning to understand the addictive-like properties of food and how repeated overconsumption of high sugar — similar to taking drugs — may affect our brains and cause compulsive behaviors,” said corresponding author Pietro Cottone, Ph.D., an associate professor of pharmacology and experimental therapeutics at BUSM and co-director of the Laboratory of Addictive Disorders.

To better understand compulsive and uncontrollable eating, Cottone and his research team performed a series of experiments on two groups of rats. One, the cycled group, received a high-sugar, chocolate-flavored diet for two days each week and a standard control diet the remaining days of the week, while the control group received the control diet all of the time.

The group that cycled between the palatable food and the less palatable food spontaneously developed compulsive, binge eating on the sweet food and refused to eat regular food, the researchers discovered.

Both groups were then injected with a psychostimulant amphetamine, a drug that releases dopamine and produces reward, and their behavior in a battery of behavioral tests was then observed.

While the control group predictably became very hyperactive after receiving amphetamine, the cycled group did not.

Furthermore, in a test of the conditioning properties of amphetamine, the control group was attracted to environments where they previously received amphetamine, whereas the cycled group were not.

Finally, when measuring the effects of amphetamine while directly stimulating the brain reward circuit, the control group was responsive to amphetamine, while the cycled group was not, according to the findings.

After investigating the biochemical and molecular properties of the mesolimbic dopamine system of both groups, the researchers determined that the cycled group had less dopamine overall, released less dopamine in response to amphetamine, and had dysfunctional dopamine transporters — proteins that carry dopamine back into brain cells — due to deficits in the mesolimbic dopamine system.

“We found that the cycled group display similar behavioral and neurobiological changes observed in drug addiction: specifically, a crash in the brain reward system,” Cottone said. “This study adds to our understanding of the neurobiology of compulsive eating behavior.

“Compulsive eating may derive from the reduced ability to feel reward. These findings also provide support to the theory that compulsive eating has similarities to drug addiction.”

“Our data suggest that a chronic cyclic pattern of overeating will reduce the brain’s ability to feel reward — feeling satiated. This results in a vicious circle, where diminished reward sensitivity may in turn be driving further compulsive eating,” said lead author Catherine (Cassie) Moore, Ph.D., a former graduate student in the Laboratory of Addictive Disorders at BUSM.

The study was published in the journal Neuropsychopharmacology.

Source: Boston University School of Medicine

Osteoarthritis May Play a Role in Social Isolation

When older adults become socially isolated, their health and well-being can suffer. Now a new study suggests a link between being socially isolated and osteoarthritis (arthritis), a condition that causes joint pain and can limit a person’s ability to get around.

The findings are published in the Journal of the American Geriatrics Society.

Arthritis patients often have other health issues which may increase their risk of becoming socially isolated. These include anxiety and depression, being afraid to move around (because arthritis makes moving painful), physical inactivity and being unable to take care of themselves.

About 30 percent of adults over 65 have arthritis to some degree, especially in their leg joints. Despite that, until now there has been little research on the link between arthritis and social isolation.

Researchers analyzed data from the European Project on OSteoArthritis (EPOSA) study. They wanted to examine any potential links between arthritis and social isolation, and to identify the disease’s contribution to social isolation.

EPOSA is a study of 2,942 adults between the ages of 65 to 85 years old who live in six European countries: Germany, Italy, the Netherlands, Spain, Sweden, and the UK. In all, 1,967 people, around the age of 73, participated in the study. Half of the participants were women, and almost 30 percent had arthritis.

The researchers looked at whether the participants were socially isolated at the beginning of the study as well as 12 to 18 months later. The participants completed questionnaires that kept track of how often they connected socially with friends and family members and how often they volunteered or participated in social activities.

At the start of the study, almost 20 percent were socially isolated. Those who weren’t socially isolated tended to be younger, had higher incomes and more education. They were also more likely to be physically active, had less physical pain, had faster walking times and were in better all-around health.

Of the 1,585 participants who weren’t considered socially isolated at the beginning of the study, 13 percent had become socially isolated 12 to 18 months later. They reported that their health and osteoarthritis had worsened, they were in more pain, had become less physically active, had slower walking times, and had depression and problems with thinking and making decisions.

The researchers say the findings suggest that osteoarthritis can increase the risk of social isolation. In particular, having problems with thinking and making decisions, as well as having slower walking times, is associated with an increased risk of becoming socially isolated.

Since social isolation can lead to poorer health, the researchers suggest that older adults with arthritis may benefit from engaging in physical activity and social activities. Specifically, they suggest that health care providers might refer people to senior centers where activities are specially designed for people with arthritis.

Source: American Geriatrics Society

 

Hope Can Aid in Recovery from Anxiety Disorders

New research suggests hope is a trait that can predict resilience and recovery from anxiety disorders.

In a new study, clinical psychologist Dr. Matthew Gallager and colleagues examined the role of hope in predicting recovery in a clinical trial of adults in cognitive behavior therapy (CBT) for common anxiety disorders.

Historically, the concept of hope has long stirred opinion. In the 16th century, German theologian Martin Luther celebrated its power, claiming “Everything that is done in this world is done by hope.” Two centuries later, Benjamin Franklin warned that “He that lives upon hope will die fasting.”

In the study, Gallagher — University of Houston associate professor of clinical psychology — assessed the role of hope in predicting recovery among a clinical trial of 223 adults. In the trial, adults were receiving cognitive-behavior therapy (CBT) for one of four common anxiety disorders: social anxiety disorder, panic disorder, generalized anxiety disorder and obsessive-compulsive disorder.

Gallagher discovered that psychotherapy can result in clear increases in hope and that changes in hope are associated with changes in anxiety symptoms. His findings appear in the journal Behavior Therapy.

“In reviewing recovery during CBT among the diverse clinical presentations, hope was a common element and a strong predictor of recovery,” said Gallagher. He also reports that moderate-to-large increases in hope and changes in hope were consistent across the five separate CBT treatment protocols.

In terms of psychotherapy, hope represents the capacity of patients to identify strategies or pathways to achieve goals and the motivation to effectively pursue those pathways.

Significantly, the results of this study indicate that hope gradually increases during the course of CBT, and increases in hope were greater for those in active treatment than for those in the waitlist comparison.

The magnitude of these changes in hope were consistent across different CBT protocols and across the four anxiety disorders examined, which underscores the broad relevance of instilling hope as an important factor in promoting recovery during psychotherapy.

“Our results can lead to a better understanding of how people are recovering and it’s something therapists can monitor. If a therapist is working with a client who isn’t making progress, or is stuck in some way, hope might be an important mechanism to guide the patient forward toward recovery,” said Gallagher.

Hope is closely related to other positive psychology constructs, such as self-efficacy and optimism, that have also been shown to have clear relevance to promoting resilience to and recovery from emotional disorders, said Gallagher.

Gallagher’s research is part of a larger project examining the efficacy of CBT for anxiety disorders led by Dr. David H. Barlow, founder and director emeritus of the Boston University Center for Anxiety and Related Disorders.

Source: University of Houston

Excessive Brain Activity Linked to Shorter Life Span

Video: New research links excess neural activity — the flickering light seen in this image — to reduced longevity. Credit: Yankner lab, Harvard Medical School.

The brain’s neural activity — long implicated in disorders ranging from dementia to epilepsy — also plays a role in how long we live.

The study, led by scientists in the Blavatnik Institute at Harvard Medical School and based on findings from human brains, mice, and worms, suggests that excessive activity in the brain is linked to shorter life spans, while suppressing overactivity can extend life.

Neural activity refers to the constant flicker of electrical currents and transmissions in the brain. Excessive activity, or excitation, could manifest in numerous ways, from a muscle twitch to a change in mood or thought, according to the researchers.

“An intriguing aspect of our findings is that something as transient as the activity state of neural circuits could have such far-ranging consequences for physiology and life span,” said study senior author Dr. Bruce Yankner, a professor of genetics and co-director of the Paul F. Glenn Center for the Biology of Aging.

Neural excitation appears to act along a chain of molecular events famously known to influence longevity — the insulin and insulin-like growth factor (IGF) signaling pathway, the researchers explain.

The key in this signaling cascade appears to be a protein called REST, previously shown by researchers in the Yankner Lab to protect aging brains from dementia and other stresses.

Study results could lead to the design of new therapies for conditions that involve neural overactivity, such as Alzheimer’s disease and bipolar disorder, the researchers said.

The findings also raise the possibility that certain medicines, such as drugs that target REST, or certain behaviors, such as meditation, could extend life span by modulating neural activity, they said.

Human variation in neural activity might have both genetic and environmental causes, which would open future avenues for therapeutic intervention, Yankner added.

The researchers began their investigation by analyzing gene expression patterns — the extent to which various genes are turned on and off — in donated brain tissue from hundreds of people who died at ages ranging from 60 to over 100.

The information was collected through three separate research studies of older adults. Those analyzed in the current study were cognitively intact, meaning they had no dementia, the researchers noted.

The researchers immediately noticed a striking difference between the older and younger study participants, Yankner said. The longest-lived people — those over 85 — had lower expression of genes related to neural excitation than those who died between the ages of 60 and 80.

Next came the question that all scientists confront: Correlation or causation? Was this disparity in neural excitation merely occurring alongside more important factors determining life span or were excitation levels directly affecting longevity? If so, how?

To answer these questions, the researchers conducted a barrage of experiments, including genetic, cell, and molecular biology tests in the model organism Caenorhabditis elegans, analyses of genetically altered mice, and additional brain tissue analyses of people who lived for more than a century.

These experiments revealed that altering neural excitation does indeed affect life span and illuminated what might be happening on a molecular level, the researchers said, noting all signs pointed to the protein REST.

REST, which is known to regulate genes, also suppresses neural excitation, the researchers found.

Blocking REST or its equivalent in the animals led to higher neural activity and earlier deaths, while boosting REST did the opposite.

The researchers also discovered that people who lived to 100 and beyond had significantly more REST in the nuclei of their brain cells than people who died in their 70s or 80s.

“It was extremely exciting to see how all these different lines of evidence converged,” said study co-author Dr. Monica Colaiácovo, a professor of genetics at Harvard Medical School, whose lab collaborated on the C. elegans work.

The researchers found that from worms to mammals, REST suppresses the expression of genes that are centrally involved in neural excitation, such as ion channels, neurotransmitter receptors, and structural components of synapses.

Lower excitation activates a family of proteins known as forkhead transcription factors. These proteins have been shown to mediate a “longevity pathway” via insulin/IGF signaling in many animals. It’s the same pathway that scientists believe can be activated by caloric restriction, according to the researchers.

In addition to its emerging role in staving off neurodegeneration, discovery of REST’s role in longevity provides additional motivation to develop drugs that target the protein, the researchers said.

Although it will take time and many tests to determine whether such treatments reduce neural excitation, promote healthy aging, or extend life span, the concept has captivated some researchers.

“The possibility that being able to activate REST would reduce excitatory neural activity and slow aging in humans is extremely exciting,” said Colaiácovo.

The study was published in Nature.

Source: Harvard Medical School

 

Exercise Can Now Be Prescribed Like Medicine for Cancer Patients

It is well known that regular exercise can help prevent and treat many forms of heart disease, but less commonly known are the benefits of physical activity for cancer patients.

A new initiative called Moving Through Cancer — led by Dr. Kathryn Schmitz, professor of public health sciences at Penn State College of Medicine, and an international team of health practitioners and researchers — is hoping to change that.

According to the researchers, exercise is important for cancer prevention, as it can lower the risk of developing colon, breast, endometrial, kidney, bladder, esophagus and stomach cancers.

Exercise during and after cancer treatment can also help improve fatigue, anxiety, depression, physical function, and quality of life and can also help increase survival rates after a breast, colon or prostate cancer diagnosis.

In their new paper published in CA: A Cancer Journal for Clinicians, Schmitz and her team outline new exercise recommendations for people living with and beyond cancer.

“With more than 43 million cancer survivors worldwide, we have a growing need to address the unique health issues facing people living with and beyond cancer and better understand how exercise may help prevent and control cancer,” said Schmitz, who is also a member of the Penn State Cancer Institute.

“This esteemed, multidisciplinary group of leaders on the forefront of exercise oncology aimed to translate the latest scientific evidence into practical recommendations for clinicians and the public and to create global impact through a unified voice.”

Depending on each patient’s activity levels and abilities, the researchers generally recommend 30 minutes of moderately intense aerobic exercise three times a week and 20 to 30 minutes of resistance exercise twice a week.

But, Schmitz said health care professionals can also customize exercise prescriptions to individual patients.

“Through our research, we’ve reached a point where we can give specific FITT exercise prescriptions — which means frequency, intensity, time and type — for specific outcomes like quality of life, fatigue, pain and others,” Schmitz said.

“For example, if we’re seeing a head and neck cancer patient with a specific set of symptoms, we could give them an exercise prescription personalized to them.”

Schmitz said the recommendations will help with one of the premier goals of Moving Through Cancer: raising public awareness about the benefits of exercise for people living with and beyond cancer by 2029.

“Currently, an average person on the street will know that exercise is good for preventing and treating heart disease, but not for melanoma,” Schmitz said.  “We want to change that. When researchers in the 1950s built an evidence base for exercise and heart disease, there was a shift in public knowledge about that connection. It’s now time for the same thing to happen with exercise and cancer.”

Schmitz said the second piece of the initiative is resources and programs to help get cancer patients moving. The Moving Through Cancer website has an exercise program registry that can help patients, families, health care providers and others find programs near them.

The final piece is policy, Schmitz said, which could be used to increase the chances that health care professionals will talk to their patients about exercise and that patients will be adequately referred as they move through cancer.

“This is the center of my professional heart,” Schmitz said. “My mission for a decade now has been that I want exercise to be as ubiquitous in cancer care as it is in cardiac disease care, only better. The new recommendations and guidance are a tool that can help make that a reality.”

Source: Penn State