Mental Health

Obesity triggers neurodegeneration by inducing brain insulin resistance

In a pivotal study conducted by Mroj Alassaf and colleagues at the Fred Hutchinson Cancer Research Center in the United States, a novel connection between obesity and the onset of neurodegenerative diseases, such as Alzheimer’s, has been uncovered.

The research, employing the biological model of the common fruit fly, indicates that diets high in sugar, which are commonly associated with obesity, lead to insulin resistance within the brain. This resistance hampers the brain’s capacity to eliminate cellular waste, which in turn elevates the risk of neurodegenerative conditions.

The findings, released on November 7 in the open-access publication PLOS Biology, promise to be influential in the development of medical interventions aimed at mitigating the chances of neurodegenerative disease onset.

While the correlation between obesity and neurodegenerative diseases like Alzheimer’s and Parkinson’s has been acknowledged in scientific circles, the causal mechanisms at play have eluded researchers until now.

The team’s research delved into this conundrum by leveraging the genetic and physiological parallels between fruit flies and humans. Building on prior knowledge that a diet rich in sugar instigates insulin resistance in the peripheral tissues of fruit flies, the focus now shifted to their neural tissues. The study zoomed in on glial cells, as abnormalities in microglia are recognised contributors to neuronal decay.

The study measured the protein PI3k—a biomarker for insulin sensitivity in cells. The high-sugar diet was found to diminish PI3k levels in glial cells, suggesting a state of insulin resistance. The team also examined the fruit fly’s version of microglia, known as ensheathing glia, responsible for clearing out neuronal waste, including deteriorating axons.

These glial cells exhibited depleted levels of Draper, a protein integral to their waste-removal function, indicating a compromised ability. Subsequent experiments demonstrated that artificially reducing PI3k levels not only caused insulin resistance but also led to decreased Draper levels in the ensheathing glia. Moreover, when the team inflicted damage on olfactory neurons, the ensheathing glia of sugar-fed flies failed to clear the resulting neuronal debris due to their unresponsive Draper levels.

The researchers conclude by stating that their work with fruit flies has established that high-sugar diets induce insulin resistance in glial cells, which disrupts their neuronal cleanup role. This study sheds light on the potential pathways through which diets leading to obesity may elevate the risk of neurodegenerative diseases.

New research links early adolescent weight gain to higher depression risks in teen years

Recent studies indicate a strong correlation between elevated body mass index (BMI) in children and increased instances of depression during their teenage years. This correlation, as pinpointed in the comprehensive research conducted by King’s College London, has flagged early adolescence as a critical period wherein weight gain can significantly influence the onset of depressive symptoms later on in life.

The King’s College London team analysed data from over 10,000 twins born from 1994 to 1996, charting their height and weight at ages 12, 16, and 21 to determine their BMI. Additionally, the young participants filled out questionnaires that helped monitor depression symptoms such as feelings of loneliness, low moods, and exhaustion.

The insights derived from the research underscored a higher tendency among children with overweight to develop depression, a risk amplified the earlier in life they started to experience weight issues. Particularly, the span between 12 and 16 years was identified as a “sensitive point,” with weight gains during this period more strongly linked to later depression compared to gains between the ages of 16 and 21.

Senior co-author of the study, Thalia Eley, Professor of Developmental Behavioural Genetics, highlighted the significant role of early adolescence in the co-evolution of obesity and depressive tendencies. She further underscored the urgency of adopting a proactive approach to fostering positive body image and wellbeing, as opposed to merely focusing on weight, to thwart the onset of depression in later years.

Echoing these sentiments, the study’s principal author, Dr. Ellen Thompson emphasised the imperative need to unravel the intricacies of the mental health-weight nexus in adolescence to devise timely and effective support mechanisms. While the current study did not delve into the underlying causes of the observed relationship, earlier studies have pointed to factors like body dissatisfaction and external weight-related stigma as potent triggers.

In light of the increasing concerns around obesity and mental health disorders amongst the UK’s youth — a demographic where one-third have overweight or obesity by the time they finish primary school — the researchers propose that educational institutions integrate positive body image narratives in their curriculum.

These recommendations come against a backdrop of an alarming rise in child mental health crises, exacerbated by the COVID-19 pandemic, and sustained school closures which have put unprecedented demand on the NHS’s mental health services for young people. According to recent statistics, one in four older teenagers are grappling with “probable” mental health disorders, a spectrum that encompasses depression and anxiety symptoms.

Furthermore, the persistent pressures from social media and the bottleneck created by long waiting lists for accessing mental health services portray a grim landscape for the younger generation. The scholars behind the study press for urgent interventions to mitigate this rapidly spiralling crisis, urging for a renewed focus on promoting a healthy body image to stave off depression and foster mental wellbeing among youth.

Exercise hormone irisin emerges as potential therapeutic agent in Alzheimer’s research

In the relentless pursuit to find effective treatments for Alzheimer’s disease, researchers have spotlighted a potential new ally: the hormone irisin, which is generated during physical exercise. This revelation brings a beacon of hope, suggesting a potential new frontier in Alzheimer’s therapy.

According to a recent study carried out by a team at the Massachusetts General Hospital in Boston, the elevation of irisin levels, encouraged through physical exercise, showcases promising results in reducing the plaque and tau tangles that are trademarks of Alzheimer’s disease. The role of irisin had been previously linked to the regulation of glucose and lipid metabolism in adipose tissue and the acceleration of the conversion of white fat tissue to brown, a process that augments energy expenditure.

Before delving deeper into irisin’s impact on Alzheimer’s, the team had pioneered the development of 3D human cell culture models of the disease. These models played a pivotal role in understanding how irisin interacts with amyloid-beta, a significant player in the Alzheimer’s landscape, present in the brain.

Previous studies on murine models had affirmed the beneficial effects of physical exercise in diminishing amyloid-beta accumulations, albeit without understanding the precise mechanism. The fresh insights gleaned from this study illuminated that irisin’s influence in this context is closely tied to the enhancement of an enzyme known as neprilysin, which is proficient in degrading amyloid-beta.

Se Hoon Choi, one of the study’s authors, illuminated that treating with irisin led to a “remarkable reduction of amyloid-beta pathology,” an effect steered by the bolstered activity of neprilysin, which is secreted in higher quantities by brain cells called astrocytes, in response to irisin.

Notably, the researchers managed to pinpoint the pathway that prompts cells to amplify neprilysin levels, opening avenues for further exploration and therapy development. The endeavour now stood grounded on a robust foundation of understanding how irisin, once introduced into the bloodstream, can navigate its way to the brain, showcasing its potential utility as a therapeutic agent.

Furthermore, senior author Rudolph Tanzi noted that irisin could be the principal orchestrator behind exercise-induced escalations in neprilysin levels that are instrumental in alleviating the amyloid-beta burden in the brain. Tanzi underscored the significant implications of these findings, propelling irisin to the centre stage as a promising target for preventive and therapeutic strategies against Alzheimer’s disease.
This groundbreaking study, published in the renowned journal Neuron on September 8 2023, brings to light irisin’s pivotal role as a mediator, leveraging the natural, exercise-induced hormone to forge a path towards revolutionary Alzheimer’s treatments. It brings us a step closer to harnessing the potential of physical exercise at a molecular level in battling the devastating impacts of Alzheimer’s, thus offering a new ray of hope in medical science’s quest to conquer this debilitating disease.

Hypothalamic differences discovered in people who are living with overweight or obesity

A groundbreaking study by researchers at the University of Cambridge has provided new insights into the role of the hypothalamus in controlling appetite. This small yet critical region of the brain, which is about the size of an almond, appears to have structural differences in those who are living with overweight or obesity compared to those of healthy weight.

Dr. Stephanie Brown from the Department of Psychiatry and Lucy Cavendish College, University of Cambridge, noted the importance of the hypothalamus in regulating appetite but also acknowledged the difficulty in studying it in living humans due to its small size.

The study team addressed this challenge by using a machine learning algorithm to analyse MRI scans of 1,351 young adults across different BMI categories. Published in Neuroimage: Clinical, their findings revealed that the hypothalamus’s overall volume was significantly larger in those who with overweight or obesity.

These findings offer further evidence to the connection between brain structure, weight, and food consumption, as obesity is a global concern affecting over 1.9 billion people worldwide. The condition increases risks for numerous health problems, including type 2 diabetes, heart disease, stroke, and mental health issues.

The team also explored the possibility that the changes in the hypothalamus might be related to inflammation. Previous animal studies have shown that a high-fat diet could cause inflammation in the hypothalamus, leading to insulin resistance and obesity. In some cases, just three days of a fat-rich diet was enough to trigger inflammation.

Dr. Brown emphasised that if similar processes occur in humans, a high-fat diet could impact our ability to sense when we’ve eaten enough, leading to weight gain. The researchers hypothesised that the brain might react to inflammation by enlarging specialised immune cells, known as glia, causing the hypothalamus to be larger.

Professor Paul Fletcher, the study’s senior author, expressed hope that this new approach to analysing brain scans would deepen our understanding of appetite control in obesity. While the exact implications of these findings are still unclear, more research is needed to confirm whether the increase in hypothalamic volume is a cause or result of being overweight, or if those with larger hypothalami are naturally inclined to eat more.

Supported by the Bernard Wolfe Health Neuroscience Fund, Wellcome, NIHR Cambridge Biomedical Research Centre, and additional funding from Alzheimer’s Research UK, the study presents a transformative view of obesity. It opens new avenues for exploring obesity from a neurological perspective, potentially revolutionising how obesity and overweight conditions are understood and treated. Future studies may provide essential insights into intervention strategies, reshaping the way we approach this global health challenge.

Rising obesity prevalence may have altered perceptions of healthy body weights, study suggests

A concerning trend has emerged, revealing that an increasing number of overweight teenagers do not perceive themselves as being too heavy. This phenomenon raises alarms as it may lead to detrimental lifestyle choices, warn scientists. The trend of underestimating body weight was found to be particularly prevalent among girls, according to a peer-reviewed study. 

The study suggests that the rising prevalence of obesity and the emergence of body trends idealising an athletic, muscular physique may contribute to teenagers underestimating their weight and becoming resistant to adopting healthy diet and exercise habits. However, the researchers acknowledge that other factors, including body image, dieting, changing eating patterns, and migration, may also play a role in these shifting perceptions over time.

Conducted by the International Health Behaviour in School-Aged Children, the study surveyed 11 to 15-year-olds between 2002 and 2018, analysing trends in body weight perception while considering age, gender, and family socioeconomic status. The survey encompassed over 745,000 adolescents from 41 countries across Europe and the United States. These findings are particularly significant for the UK, where more than a third of teenagers have either overweight or obesity.

Lead author of the study, Dr. Anouk Geraets from the Department of Social Sciences at the University of Luxembourg, emphasised the potential impact of body weight perception during this impressionable age on teenagers’ lifestyle choices, including their food consumption and exercise habits. Dr. Geraets expressed concern regarding the trend of fewer adolescents perceiving themselves as overweight, as this could undermine efforts to address the escalating obesity levels among this age group. Teenagers who underestimate their weight may not recognize the need to lose excess weight and may consequently make unhealthy lifestyle choices.

The study revealed an increase in underestimation of weight status and a decrease in overestimation over time, with girls being more susceptible to these perceptions than boys. Scientists worry that shifting trends in perception could diminish the effectiveness of public health interventions targeting young people.

Dr. Geraets emphasised the clinical and public health implications of the study. While the increase in accurate weight perception and the decrease in overestimation may have a positive impact by reducing unnecessary and unhealthy weight loss behaviours among adolescents, the rise in underestimation highlights the need for interventions to strengthen accurate weight perception. Further research is necessary to understand the underlying factors driving these trends and to develop effective public health interventions.
The study’s findings were published in the journal Child and Adolescent Obesity, shedding light on the urgent need to address teenagers’ misperceptions of their weight in order to promote healthier lifestyles and combat the growing obesity crisis among this age group.

Study reveals obesity as a precursor to mental disorders across all ages

A recent study conducted by the Medical University of Vienna in collaboration with the Complexity Science Hub Vienna has uncovered that individuals suffering from obesity face an elevated risk of developing various mental disorders across all age groups. Interestingly, the study reveals that women are more susceptible than men to most of these disorders. The research findings were published in Translational Psychiatry, a renowned scientific journal.

The researchers meticulously analysed a comprehensive dataset, encompassing all inpatient hospitalisations in Austria between 1997 and 2014. The aim was to ascertain the relative risks of coexisting diseases in individuals with obesity and to pinpoint any statistically significant variations between genders. The data illustrated that an obesity diagnosis markedly heightens the likelihood of developing an array of mental disorders, including depression, nicotine addiction, psychosis, anxiety, eating disorders, and personality disorders.

Michael Leutner, who headed the study and is part of the Department of Internal Medicine II at MedUni Vienna, asserted, “The findings highlight the imperative need for increased vigilance toward psychiatric diagnoses in patients with obesity and engaging specialists early on if necessary.”

Elma Dervic, the co-first author of the study from the Complexity Science Hub, expounded on the innovative approach adopted to discern which illness typically manifested before or after an obesity diagnosis. “This novel method enabled us to identify trends and common patterns in the onset of diseases,” Dervic explained. The study revealed that, with the exception of disorders in the psychosis spectrum, obesity was likely to be diagnosed before the emergence of any psychiatric condition.

Contrary to a widely-held belief among physicians that psychopharmacological medications were responsible for the connection between mental disorders and obesity, the study suggests otherwise. “While this might hold true for schizophrenia, our data does not corroborate this for depression or other mental disorders,” elucidated Alexander Kautzky, the first author from the Department of Psychiatry and Psychotherapy at MedUni Vienna. However, it remains uncertain whether obesity directly impacts mental health or if early stages of psychiatric disorders are frequently overlooked.

Notably, the study found women to be more predisposed to nearly all mental disorders, except for schizophrenia and nicotine addiction. Approximately 16.66% of men with obesity were found to have nicotine addiction compared to just 8.58% of women with obesity. Conversely, the rate of diagnosed depression was nearly threefold higher in women with obesity (13.3% in women with obesity compared to 4.8% in women who did not have obesity) than in men with obesity (6.61% in men with obesity compared to 3.21% in men who did not have obesity).

With over 670 million individuals affected by obesity globally, it is well-established that obesity contributes to metabolic disorders and severe cardio-metabolic complications such as diabetes mellitus, arterial hypertension, and dyslipidemia. The revelation that obesity is frequently a precursor to serious mental disorders underscores its significance as a health risk factor, particularly for younger populations where the risk is most pronounced.

Consequently, the researchers stress the urgency for comprehensive mental health screening amongst patients with obesity to enable timely preventive measures or the provision of appropriate treatment.

Obesity alters brain function, hindering weight loss maintenance, study finds

Researchers from Amsterdam UMC and Yale University have recently unveiled a ground-breaking link between obesity and altered brain responses to nutrients. Their study indicates that obesity leads to reduced dopamine release and diminished nutrient-sensing activity in the brain. Worryingly, these changes persist even after weight loss, potentially explaining why maintaining weight loss is so challenging for many.

The research, published in Nature Metabolism, highlights that the brain’s responses to certain nutrients are impaired in individuals with obesity and don’t show improvement even after shedding weight.

Mireille Serlie, the lead researcher and Professor of Endocrinology at Amsterdam UMC, elaborates on the implications of the study, “Our results point toward enduring alterations in the brain among individuals with obesity, which could have a substantial impact on eating behaviour. We observed that, compared to individuals of normal weight, those with obesity exhibited lower dopamine release in a brain region that plays a pivotal role in the motivation associated with food consumption. Dopamine is crucial for the rewarding aspects of eating. Moreover, those with obesity demonstrated diminished brain activity in response to the infusion of nutrients into the stomach. Collectively, these results suggest that the brain’s ability to sense nutrients in the stomach and gut, or to process nutritional signals, is compromised in obesity, which may have significant repercussions on food intake.”

The regulation of food consumption is dependent on a complex interplay of metabolic and neural signals among the brain and various organs, such as the gut, as well as nutritional signals in the blood. This intricate network governs hunger and satiety sensations, regulates food intake, and controls the motivation to seek food. Though advances have been made in understanding these processes in animals, especially regarding metabolic diseases like obesity, less is known about the human mechanisms, mainly due to challenges in creating experimental setups within clinical settings that can elucidate these processes.

Addressing this knowledge gap, Serlie and her team, including colleagues from Yale, conducted a meticulously designed controlled trial. The study involved 30 participants with obesity and 30 of normal weight. It entailed infusing specific nutrients directly into the participants’ stomachs while simultaneously assessing their brain activity using MRI scans and monitoring dopamine release with SPECT scans.

The study discovered that while participants of normal weight showed distinct patterns of brain activity and dopamine release in response to nutrient infusion, these responses were significantly weakened in those with obesity. Furthermore, even after achieving a 10% body weight loss through a 12-week diet, the brain responses in individuals with obesity did not improve. This finding suggests that obesity induces long-term adaptations in the brain that persist even after weight loss.

“The enduring nature of these brain alterations, which do not reverse even after weight loss, might elucidate why so many individuals tend to regain weight following initial successful weight loss,” Serlie concludes.

This discovery brings to light the intricate challenges faced by those striving to lose weight and maintain the loss, suggesting that strategies need to address not only the physical aspects but also the neurological factors entangled with obesity.

AI shows potential as a beneficial aid in mental health treatment, UIC study indicates

A recent pilot study by researchers from the University of Illinois Chicago (UIC) brings forth promising insights into the application of Artificial Intelligence (AI) in mental health treatment. The study demonstrates encouraging correlations between the use of an AI voice assistant named Lumen and improvements in symptoms of depression and anxiety in patients, along with noticeable changes in their brain activity.

The UIC study brings hope for the inclusion of virtual therapy in addressing the existing gaps in mental health care. The limited availability of mental health professionals and unequal access to mental health services, particularly among vulnerable communities, often impede proper treatment. The application of AI could potentially circumvent these obstacles.

Dr. Olusola A. Ajilore, UIC Professor of Psychiatry and a co-author of the study, noted the urgent necessity for innovative treatment methods, especially in the aftermath of COVID-19, which resulted in a surge of anxiety and depression cases. He remarked, “This technology could serve as a bridge. It isn’t meant to supersede traditional therapy, but it could be a vital intermediary measure before someone seeks treatment.”

Lumen, which functions as a skill within the Amazon Alexa application, is the brainchild of Dr. Ajilore, Dr. Jun Ma, the senior author of the study, and their colleagues from Washington University in St. Louis and Pennsylvania State University. The National Institute of Mental Health provided a $2 million grant to support the development of Lumen.

The researchers enlisted over 60 patients for this clinical study, which focused on the effect of the application on mild to moderate symptoms of depression and anxiety. The study also looked at activity in brain areas that have been associated with the advantages of problem-solving therapy. Two-thirds of the participants engaged with Lumen through a study-provided iPad for eight problem-solving therapy sessions. The remaining participants served as a control group that did not receive any intervention.

Upon concluding the intervention, the participants who interacted with the Lumen app exhibited reduced scores for depression, anxiety, and psychological distress in comparison to the control group. Moreover, these participants demonstrated enhanced problem-solving skills and increased activity in the dorsolateral prefrontal cortex, a brain region related to cognitive control. The results showed particular promise among women and underrepresented populations.

Dr. Ma highlighted the significance of problem-solving therapy delivered through the Lumen app. He stated, “It’s about reshaping the way people perceive problems and their approach to solving them without being overwhelmed by emotions.”

A comprehensive trial comparing the efficacy of Lumen to a control group on a waitlist and patients receiving human-guided problem-solving therapy is presently underway. However, Dr. Ma emphasises that the aim of the virtual coach is not to outperform human therapists but to address the critical shortages in the mental health system.

He concluded, “Digital mental health services should be viewed as a means to bridge the gap between the supply and demand of mental health care. We need to identify innovative, effective, and safe ways to deliver treatments to individuals who might otherwise lack access, thereby filling this gap.”

Mediterranean diet linked to fewer signs of Alzheimer’s disease

According to a recent study, following a diet rich in leafy green vegetables, whole grains, nuts, and fish could result in fewer signs of Alzheimer’s disease. The study found that older adults who followed the MIND and Mediterranean diets had fewer amyloid plaques and tau tangles in their brains. While researchers are yet to establish a cause-and-effect relationship, the study showed that consuming specific foods can enhance brain health.

Individuals following the Mediterranean diet had levels of plaque and tangles in their brains similar to that of people 18 years younger than those who consumed the least brain-healthy foods. For those following the MIND diet, the figure was 12 years younger.

The Mediterranean diet contains food items from countries bordering the Mediterranean Sea, such as Italy, Greece, Cyprus, and Spain, including olive oil, dairy products, poultry, fish, fruits, vegetables, whole grains, legumes, nuts, and seeds.

The MIND diet, on the other hand, combines the DASH (Dietary Approaches to Stop Hypertension) and Mediterranean diets. It promotes eating leafy green vegetables, berries, nuts, and whole grains. It is also recommended to consume at least one serving of fish per week.

The study involved 581 older adults who agreed to donate their brains for research after death. Before dying, 39% were diagnosed with dementia, and after death, 66% met the criteria for Alzheimer’s disease. Participants completed yearly questionnaires about their eating habits, which were analysed and scored based on the type and quality of the food they consumed.

One of the most noteworthy findings of the study was that consuming green leafy vegetables corresponded to a lower amount of plaque in the brain, almost 19 years younger than those who ate less. However, researchers could not establish a direct relationship between a healthy diet and fewer brain deposits of amyloid plaques, known as an indicator of Alzheimer’s disease.

Dr. Puja Agarwal, a study author, said that improvement in people’s diets in one area, such as eating green leafy vegetables or not consuming fried foods, was associated with fewer amyloid plaques in the brain, similar to being around four years younger. The study provides evidence for a real food approach to eating, which focuses on natural, unprocessed or minimally processed foods while reducing processed or ultra-processed foods.

Scientists find link between obesity and dementia

According to a new study published in the journal Alzhiemers & Dementia journal , obesity could be a major factor in the development of dementia. Researchers found that having overweight or obesity in mid-life could increase the risk of developing Alzheimer’s disease and other forms of dementia later in life.

The study analysed data from over 1.3 million adults in the United States, Europe, and Asia. It found that people who had overweight or obesity in mid-life had a 31% higher risk of developing dementia than those who were of a normal weight. The risk increased to 82% for those who had severe obesity.

The researchers also found that having type 2 diabetes further increased the risk of developing dementia in individuals with overweight or obesity. This is because obesity and diabetes are both associated with inflammation, insulin resistance, and other metabolic abnormalities that can damage the brain and increase the risk of dementia.

The study’s lead author, Dr. Elina Hyppönen, emphasised that the findings highlight the importance of maintaining a healthy weight throughout life to reduce the risk of dementia. She suggested that lifestyle interventions, such as exercise and a healthy diet, could help prevent obesity and diabetes and lower the risk of dementia.

The study’s findings add to the growing body of evidence linking obesity and dementia. Previous research has suggested that obesity can increase the risk of cognitive decline and reduce brain volume, particularly in the hippocampus, which is critical for memory and learning.

The World Health Organization estimates that around 50 million people worldwide have dementia, and that number is expected to triple by 2050. The study’s authors suggest that preventing obesity and diabetes could be an important strategy for reducing the global burden of dementia.

Can cognitive behavioural therapy (CBT) help with weight loss?

Cognitive behavioural therapy (CBT) is a type of talk therapy that focuses on identifying unhelpful thoughts and behaviours and replacing them with more positive and constructive ones. 

This therapy aims to help people overcome a variety of issues, including anxiety, depression, phobias, substance use disorders, eating disorders, insomnia, relationships, self-esteem, and personality disorders. CBT is not intended to be ongoing, and typically involves regular sessions with a therapist for anywhere from 4 to more than 20 sessions, depending on the issue being addressed.

CBT can be particularly helpful for people who struggle with weight management, as it focuses on changing the behavioural patterns that contribute to weight gain. For example, if someone tends to overeat in response to stress, CBT can help them develop more positive coping strategies to manage their stress. CBT is also considered a preferred treatment for obesity and binge-eating disorder (BED).

To use CBT for weight loss, a therapist will help an individual set specific and attainable goals, such as reaching a target weight range or adopting a healthier lifestyle. The therapist will also encourage self-monitoring to help the individual become aware of their eating behaviours and to identify potential setback triggers, such as boredom or stress eating. 

By identifying these triggers early on, the individual can take steps to correct them and avoid undoing their progress. The therapist may also offer feedback and reinforcement to help the individual stay motivated and track their progress. While CBT can be a highly effective way to change habits and patterns of thinking, it’s important to remember that lifestyle and behavioural training can take time, and progress may not happen overnight.